An Applet for the Investigation of Simpson's Paradox

ERIC Educational Resources Information Center

Schneiter, Kady; Symanzik, Jurgen

2013-01-01

This article describes an applet that facilitates investigation of Simpson's Paradox in the context of a number of real and hypothetical data sets. The applet builds on the Baker-Kramer graphical representation for Simpson's Paradox. The implementation and use of the applet are explained. This is followed by a description of how the applet has…

Income Inequality Explains Why Economic Growth Does Not Always Translate to an Increase in Happiness.

PubMed

Oishi, Shigehiro; Kesebir, Selin

2015-10-01

One of the most puzzling social science findings in the past half century is the Easterlin paradox: Economic growth within a country does not always translate into an increase in happiness. We provide evidence that this paradox can be partly explained by income inequality. In two different data sets covering 34 countries, economic growth was not associated with increases in happiness when it was accompanied by growing income inequality. Earlier instances of the Easterlin paradox (i.e., economic growth not being associated with increasing happiness) can thus be explained by the frequent concurrence of economic growth and growing income inequality. These findings suggest that a more even distribution of growth in national wealth may be a precondition for raising nationwide happiness. © The Author(s) 2015.

Space Curvature and the "Heavy Banana 'Paradox.'"

ERIC Educational Resources Information Center

Gruber, Ronald P.; And Others

1991-01-01

Two ways to visually enhance the concept of space curvature are described. Viewing space curvature as a meterstick contraction and the heavy banana "paradox" are discussed. The meterstick contraction is mathematically explained. (KR)

A preliminary and qualitative study of resource ratio theory to nitrifying lab-scale bioreactors.

PubMed

Bellucci, Micol; Ofiţeru, Irina D; Beneduce, Luciano; Graham, David W; Head, Ian M; Curtis, Thomas P

2015-05-01

The incorporation of microbial diversity in design would ideally require predictive theory that would relate operational parameters to the numbers and distribution of taxa. Resource ratio-theory (RRT) might be one such theory. Based on Monod kinetics, it explains diversity in function of resource-ratio and richness. However, to be usable in biological engineered system, the growth parameters of all the bacteria under consideration and the resource supply and diffusion parameters for all the relevant nutrients should be determined. This is challenging, but plausible, at least for low diversity groups with simple resource requirements like the ammonia oxidizing bacteria (AOB). One of the major successes of RRT was its ability to explain the 'paradox of enrichment' which states that diversity first increases and then decreases with resource richness. Here, we demonstrate that this pattern can be seen in lab-scale-activated sludge reactors and parallel simulations that incorporate the principles of RRT in a floc-based system. High and low ammonia and oxygen were supplied to continuous flow bioreactors with resource conditions correlating with the composition and diversity of resident AOB communities based on AOB 16S rDNA clone libraries. Neither the experimental work nor the simulations are definitive proof for the application of RRT in this context. However, it is sufficient evidence that such approach might work and justify a more rigorous investigation. © 2015 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Social diversity promotes the emergence of cooperation in public goods games.

PubMed

Santos, Francisco C; Santos, Marta D; Pacheco, Jorge M

2008-07-10

Humans often cooperate in public goods games and situations ranging from family issues to global warming. However, evolutionary game theory predicts that the temptation to forgo the public good mostly wins over collective cooperative action, and this is often also seen in economic experiments. Here we show how social diversity provides an escape from this apparent paradox. Up to now, individuals have been treated as equivalent in all respects, in sharp contrast with real-life situations, where diversity is ubiquitous. We introduce social diversity by means of heterogeneous graphs and show that cooperation is promoted by the diversity associated with the number and size of the public goods game in which each individual participates and with the individual contribution to each such game. When social ties follow a scale-free distribution, cooperation is enhanced whenever all individuals are expected to contribute a fixed amount irrespective of the plethora of public goods games in which they engage. Our results may help to explain the emergence of cooperation in the absence of mechanisms based on individual reputation and punishment. Combining social diversity with reputation and punishment will provide instrumental clues on the self-organization of social communities and their economical implications.

A rational explanation of wave-particle duality of light

NASA Astrophysics Data System (ADS)

Rashkovskiy, S. A.

2013-10-01

The wave-particle duality is a fundamental property of the nature. At the same time, it is one of the greatest mysteries of modern physics. This gave rise to a whole direction in quantum physics - the interpretation of quantum mechanics. The Wiener experiments demonstrating the wave-particle duality of light are discussed. It is shown that almost all interpretations of quantum mechanics allow explaining the double-slit experiments, but are powerless to explain the Wiener experiments. The reason of the paradox, associated with the wave-particle duality is analyzed. The quantum theory consists of two independent parts: (i) the dynamic equations describing the behavior of a quantum object (for example, the Schrodinger or Maxwell equations), and (ii) the Born's rule, the relation between the wave function and the probability of finding the particle at a given point. It is shown that precisely the Born's rule results in paradox in explaining the wave-particle duality. In order to eliminate this paradox, we propose a new rational interpretation of the wave-particle duality and associated new rule, connecting the corpuscular and wave properties of quantum objects. It is shown that this new rational interpretation of the wave-particle duality allows using the classic images of particle and wave in explaining the quantum mechanical and optical phenomena, does not result in paradox in explaining the doubleslit experiments and Wiener experiments, and does not contradict to the modern quantum mechanical concepts. It is shown that the Born's rule follows immediately from proposed new rules as an approximation.

One-Piece Faraday Generator: A Paradoxical Experiment from 1851

ERIC Educational Resources Information Center

Crooks, M. J.; And Others

1978-01-01

Describes an experiment based on Faraday's one-piece generator, where the rotating disk is replaced by a cylindrical permanent magnet. Explains the apparent paradox that an observer in an inertial frame could measure his absolute velocity. (GA)

Correlations between adult mimicry and larval host plants in ithomiine butterflies.

PubMed

Willmott, Keith R; Mallet, James

2004-08-07

The apparent paradox of multiple coexisting wing pattern mimicry 'rings' in tropical butterflies has been explained as a result of microhabitat partitioning in adults. However, very few studies have tested this hypothesis. In neotropical forests, ithomiine butterflies dominate and display the richest diversity of mimicry rings. We show that co-mimetic species occupy the same larval host-plant species significantly more often than expected in two out of five communities that we surveyed; in one of these, the effect remains significant after phylogenetic correction. This relationship is most probably a result of a third correlated variable, such as microhabitat. Host-plant microhabitat may constrain adult movement, or host-plant choice may depend on butterfly microhabitat preferences and mimicry associations. This link between mimicry and host plant could help explain some host-plant and mimicry shifts, which have been important in the radiation of this speciose tropical group.

Quantum paradoxes, entanglement and their explanation on the basis of quantization of fields

NASA Astrophysics Data System (ADS)

Melkikh, A. V.

2017-01-01

Quantum entanglement is discussed as a consequence of the quantization of fields. The inclusion of quantum fields self-consistently explains some quantum paradoxes (EPR and Hardy’s paradox). The definition of entanglement was introduced, which depends on the maximum energy of the interaction of particles. The destruction of entanglement is caused by the creation and annihilation of particles. On this basis, an algorithm for quantum particle evolution was formulated.

Pricing of drugs with heterogeneous health insurance coverage.

PubMed

Ferrara, Ida; Missios, Paul

2012-03-01

In this paper, we examine the role of insurance coverage in explaining the generic competition paradox in a two-stage game involving a single producer of brand-name drugs and n quantity-competing producers of generic drugs. Independently of brand loyalty, which some studies rely upon to explain the paradox, we show that heterogeneity in insurance coverage may result in higher prices of brand-name drugs following generic entry. With market segmentation based on insurance coverage present in both the pre- and post-entry stages, the paradox can arise when the two types of drugs are highly substitutable and the market is quite profitable but does not have to arise when the two types of drugs are highly differentiated. However, with market segmentation occurring only after generic entry, the paradox can arise when the two types of drugs are weakly substitutable, provided, however, that the industry is not very profitable. In both cases, that is, when market segmentation is present in the pre-entry stage and when it is not, the paradox becomes more likely to arise as the market expands and/or insurance companies decrease deductibles applied on the purchase of generic drugs. Copyright © 2012 Elsevier B.V. All rights reserved.

The explanation of the twin paradox using Poincare transformation and computer algebra system REDUCE

NASA Astrophysics Data System (ADS)

Hermanto, Arief

2012-06-01

We explain the twin (A and B) paradox using Poincare transformation (as the generalization of Lorentz transformation) in Special Relativity. We want to emphasize the fact that the paradox can really be explained in the context of Special Relativity. The twin A stays at home whereas B makes a round trip. We can still stay in Special Relativity if the non-inertial reference frame of B is in the form of a set of two inertial frames (K1 and K2) moving with different velocities with respect to a fixed inertial reference frame (K0) of A. K1 and K2 are each connected to K0 with Poincare Transformation. We use the CAS (computer algebra system) REDUCE to assist the computation. To make the discussion realistic and simpler we use rational numbers (so that we will get exact computational results) instead of symbols. The important point is that we will show how the fact can be understood by both parties (A and B) by simulating numerically the trip from the points of view of each A and B. A will accept the fact that B is younger and B will also accept the fact that A is older at the reunion. We hope the paradox will thus be explained away satisfactorily.

Tensions and Paradoxes in Teaching: Implications for Teacher Education

ERIC Educational Resources Information Center

Ben-Peretz, Miriam; Flores, Maria Assunção

2018-01-01

This paper focuses on the tensions and paradoxes in teaching. At present time, teacher education has the obligation to prepare teachers for diverse student populations, living in a highly varied context. This situation creates several competing expectations of the meaning of teacher education. For instance, preparing for professional autonomy in a…

Diversity, Adult Education and the Future: A Tentative Exploration

ERIC Educational Resources Information Center

Zepke, Nick

2005-01-01

Diversity in its many guises is strongly championed in the adult education literature. To conceive a future for adult education that is not diverse and does not try to address the needs of diverse learners seems absurd. Yet, diversity is not a unitary concept, having many definitions and paradoxical effects. Questions arise about its future in a…

Impact of Measurement Error on Statistical Power: Review of an Old Paradox.

ERIC Educational Resources Information Center

Williams, Richard H.; And Others

1995-01-01

The paradox that a Student t-test based on pretest-posttest differences can attain its greatest power when the difference score reliability is zero was explained by demonstrating that power is not a mathematical function of reliability unless either true score variance or error score variance is constant. (SLD)

A resource-based game theoretical approach for the paradox of the plankton.

PubMed

Huang, Weini; de Araujo Campos, Paulo Roberto; Moraes de Oliveira, Viviane; Fagundes Ferrreira, Fernando

2016-01-01

The maintenance of species diversity is a central focus in ecology. It is not rare to observe more species than the number of limiting resources, especially in plankton communities. However, such high species diversity is hard to achieve in theory under the competitive exclusion principles, known as the plankton paradox. Previous studies often focus on the coexistence of predefined species and ignore the fact that species can evolve. We model multi-resource competitions using evolutionary games, where the number of species fluctuates under extinction and the appearance of new species. The interspecific and intraspecific competitions are captured by a dynamical payoff matrix, which has a size of the number of species. The competition strength (payoff entries) is obtained from comparing the capability of species in consuming resources, which can change over time. This allows for the robust coexistence of a large number of species, providing a possible solution to the plankton paradox.

A resource-based game theoretical approach for the paradox of the plankton

PubMed Central

de Araujo Campos, Paulo Roberto; Moraes de Oliveira, Viviane

2016-01-01

The maintenance of species diversity is a central focus in ecology. It is not rare to observe more species than the number of limiting resources, especially in plankton communities. However, such high species diversity is hard to achieve in theory under the competitive exclusion principles, known as the plankton paradox. Previous studies often focus on the coexistence of predefined species and ignore the fact that species can evolve. We model multi-resource competitions using evolutionary games, where the number of species fluctuates under extinction and the appearance of new species. The interspecific and intraspecific competitions are captured by a dynamical payoff matrix, which has a size of the number of species. The competition strength (payoff entries) is obtained from comparing the capability of species in consuming resources, which can change over time. This allows for the robust coexistence of a large number of species, providing a possible solution to the plankton paradox. PMID:27602293

The Lure of Internationalization: Paradoxical Discourses of Transnational Student Mobility, Linguistic Diversity and Cross-Cultural Exchange

ERIC Educational Resources Information Center

Fabricius, Anne H.; Mortensen, Janus; Haberland, Hartmut

2017-01-01

This paper scrutinizes a set of paradoxes arising from a mismatch between contemporary discourses that praise and promote mobility in and internationalization of higher education, and the everyday effects of mobility and internationalization on university teaching and learning practice. We begin with a general characterization of the discourse of…

Paradoxical Personality and Academic Achievement in College Students From Buenos Aires

PubMed Central

Freiberg Hoffmann, Agustín; Fernández Liporace, María Mercedes

2015-01-01

This paper presents a study on paradoxical personality, defined as a distinctive feature in creative persons, developed with 350 college students from Buenos Aires. Goals aimed at describing and analysing possible significant differences of paradoxical traits in students from diverse majors representing seven different fields of study, and examining the relationship between each bipolar trait and academic achievement. The sample was composed of 7 groups (n = 50 by group) representing fields of study typically offered in public universities, Biology, Computer Science, Engineering, Law, Nutrition, Psychology, and History of Art. Analyses by career provided descriptive information about students of these majors, concerning their paradoxical personality profiles. Correlational studies verified significant associations between academic achievement and most paradoxical traits in majors such as Computer Science, Nutrition and Psychology. Results are discussed regarding practical outcomes and teaching programs. PMID:27247680

Biotic Interactions Shape the Ecological Distributions of Staphylococcus Species

PubMed Central

Kastman, Erik K.; Kamelamela, Noelani; Norville, Josh W.; Cosetta, Casey M.; Dutton, Rachel J.

2016-01-01

ABSTRACT Many metagenomic sequencing studies have observed the presence of closely related bacterial species or genotypes in the same microbiome. Previous attempts to explain these patterns of microdiversity have focused on the abiotic environment, but few have considered how biotic interactions could drive patterns of microbiome diversity. We dissected the patterns, processes, and mechanisms shaping the ecological distributions of three closely related Staphylococcus species in cheese rind biofilms. Paradoxically, the most abundant species (S. equorum) is the slowest colonizer and weakest competitor based on growth and competition assays in the laboratory. Through in vitro community reconstructions, we determined that biotic interactions with neighboring fungi help resolve this paradox. Species-specific stimulation of the poor competitor by fungi of the genus Scopulariopsis allows S. equorum to dominate communities in vitro as it does in situ. Results of comparative genomic and transcriptomic experiments indicate that iron utilization pathways, including a homolog of the S. aureus staphyloferrin B siderophore operon pathway, are potential molecular mechanisms underlying Staphylococcus-Scopulariopsis interactions. Our integrated approach demonstrates that fungi can structure the ecological distributions of closely related bacterial species, and the data highlight the importance of bacterium-fungus interactions in attempts to design and manipulate microbiomes. PMID:27795388

Enjoying Sad Music: Paradox or Parallel Processes?

PubMed Central

Schubert, Emery

2016-01-01

Enjoyment of negative emotions in music is seen by many as a paradox. This article argues that the paradox exists because it is difficult to view the process that generates enjoyment as being part of the same system that also generates the subjective negative feeling. Compensation theories explain the paradox as the compensation of a negative emotion by the concomitant presence of one or more positive emotions. But compensation brings us no closer to explaining the paradox because it does not explain how experiencing sadness itself is enjoyed. The solution proposed is that an emotion is determined by three critical processes—labeled motivational action tendency (MAT), subjective feeling (SF) and Appraisal. For many emotions the MAT and SF processes are coupled in valence. For example, happiness has positive MAT and positive SF, annoyance has negative MAT and negative SF. However, it is argued that in an aesthetic context, such as listening to music, emotion processes can become decoupled. The decoupling is controlled by the Appraisal process, which can assess if the context of the sadness is real-life (where coupling occurs) or aesthetic (where decoupling can occur). In an aesthetic context sadness retains its negative SF but the aversive, negative MAT is inhibited, leaving sadness to still be experienced as a negative valanced emotion, while contributing to the overall positive MAT. Individual differences, mood and previous experiences mediate the degree to which the aversive aspects of MAT are inhibited according to this Parallel Processing Hypothesis (PPH). The reason for hesitancy in considering or testing PPH, as well as the preponderance of research on sadness at the exclusion of other negative emotions, are discussed. PMID:27445752

The quantum measurement problem.

PubMed

Leggett, A J

2005-02-11

Despite the spectacular success of quantum mechanics (QM) over the last 80 years in explaining phenomena observed at the atomic and subatomic level, the conceptual status of the theory is still a topic of lively controversy. Most of the discussion centers around two famous paradoxes (or, as some would have it, pseudoparadoxes) associated, respectively, with the names of Einstein, Podolsky, and Rosen (EPR) and with Schrodinger's cat. In this Viewpoint, I will concentrate on the paradox of Schrodinger's cat or, as it is often known (to my mind somewhat misleadingly), the quantum measurement paradox.

Implementing Parrondo's paradox with two-coin quantum walks

NASA Astrophysics Data System (ADS)

Rajendran, Jishnu; Benjamin, Colin

2018-02-01

Parrondo's paradox is ubiquitous in games, ratchets and random walks. The apparent paradox, devised by J. M. R. Parrondo, that two losing games A and B can produce a winning outcome has been adapted in many physical and biological systems to explain their working. However, proposals on demonstrating Parrondo's paradox using quantum walks failed for a large number of steps. In this work, we show that instead of a single coin if we consider a two-coin initial state which may or may not be entangled, we can observe a genuine Parrondo's paradox with quantum walks. Furthermore, we focus on reasons for this and pin down the asymmetry in initial two-coin state or asymmetry in shift operator, either of which is necessary for observing a genuine Parrondo's paradox. We extend our work to a three-coin initial state too with similar results. The implications of our work for observing quantum ratchet-like behaviour using quantum walks are also discussed.

Implementing Parrondo’s paradox with two-coin quantum walks

PubMed Central

Rajendran, Jishnu

2018-01-01

Parrondo’s paradox is ubiquitous in games, ratchets and random walks. The apparent paradox, devised by J. M. R. Parrondo, that two losing games A and B can produce a winning outcome has been adapted in many physical and biological systems to explain their working. However, proposals on demonstrating Parrondo’s paradox using quantum walks failed for a large number of steps. In this work, we show that instead of a single coin if we consider a two-coin initial state which may or may not be entangled, we can observe a genuine Parrondo’s paradox with quantum walks. Furthermore, we focus on reasons for this and pin down the asymmetry in initial two-coin state or asymmetry in shift operator, either of which is necessary for observing a genuine Parrondo’s paradox. We extend our work to a three-coin initial state too with similar results. The implications of our work for observing quantum ratchet-like behaviour using quantum walks are also discussed. PMID:29515873

The paradox of enrichment in phytoplankton by induced competitive interactions

PubMed Central

Tubay, Jerrold M.; Ito, Hiromu; Uehara, Takashi; Kakishima, Satoshi; Morita, Satoru; Togashi, Tatsuya; Tainaka, Kei-ichi; Niraula, Mohan P.; Casareto, Beatriz E.; Suzuki, Yoshimi; Yoshimura, Jin

2013-01-01

The biodiversity loss of phytoplankton with eutrophication has been reported in many aquatic ecosystems, e.g., water pollution and red tides. This phenomenon seems similar, but different from the paradox of enrichment via trophic interactions, e.g., predator-prey systems. We here propose the paradox of enrichment by induced competitive interactions using multiple contact process (a lattice Lotka-Volterra competition model). Simulation results demonstrate how eutrophication invokes more competitions in a competitive ecosystem resulting in the loss of phytoplankton diversity in ecological time. The paradox is enhanced under local interactions, indicating that the limited dispersal of phytoplankton reduces interspecific competition greatly. Thus, the paradox of enrichment appears when eutrophication destroys an ecosystem either by elevated interspecific competition within a trophic level and/or destabilization by trophic interactions. Unless eutrophication due to human activities is ceased, the world's aquatic ecosystems will be at risk. PMID:24089056

The Paradox of Educational Quality and Education Policy in Hong Kong and Macau: A Postcolonial Perspective

ERIC Educational Resources Information Center

Chou, Bill K. P.

2012-01-01

This article seeks to explain a paradox concerning education qualities and reform in Hong Kong and Macau: Hong Kong is ranked higher than Macau on Program for International Student Assessment and various world university leagues. Even so, the education reform in Hong Kong is more profound and vigorous than that in Macau. From the postcolonial…

Measurement Invariance of the Pay Satisfaction Questionnaire across Gender: Explaining the "Contented Female Worker Paradox" More Thoroughly

ERIC Educational Resources Information Center

De Gieter, S.; Hofmans, J.; De Cooman, R.; Pepermans, R.

2009-01-01

Although women tend to earn less for doing similar jobs, research indicates that they are at least as satisfied with their pay as their male colleagues. In examining explanations for this "paradox of the contented female worker," the Pay Satisfaction Questionnaire (PSQ) is often used to measure and compare the pay satisfaction of both…

Do Attitudes toward School Influence the Underachievement of Turkish and Moroccan Minority Students in Flanders? The Attitude-Achievement Paradox Revisited

ERIC Educational Resources Information Center

D'hondt, Fanny; Van Praag, Lore; Stevens, Peter A. J.; Van Houtte, Mieke

2015-01-01

While many ethnic minority students underachieve compared with their ethnic majority peers, they often hold very positive school attitudes. Mickelson (1990) explained this attitude-achievement paradox by the existence of a double set of attitudes. Abstract attitudes reflect the dominant ideas about schooling, while concrete attitudes refer to a…

Solution of Supplee's submarine paradox through special and general relativity

NASA Astrophysics Data System (ADS)

Vieira, R. S.

2016-12-01

In 1989 Supplee described an apparent relativistic paradox on which a submarine seems to sink to observers at rest within the ocean, but it rather seems to float in the submarine proper frame. In this letter, we show that the paradox arises from a misuse of the Archimedes principle in the relativistic case. Considering first the special relativity, we show that any relativistic force field can be written in the Lorentz form, so that it can always be decomposed into a static (electric-like) and a dynamic (magnetic-like) part. These gravitomagnetic effects provide a relativistic formulation of Archimedes principle, from which the paradox is explained. Besides, if the curved spacetime on the vicinity of the Earth is taken into account, we show that the gravitational force exerted by the Earth on a moving body must increase with the speed of the body. The submarine paradox is then analyzed again with this speed-dependent gravitational force.

Diversity and Diversity Management: Messages from Recent Research

ERIC Educational Resources Information Center

Morrison, Marlene; Lumby, Jacky; Sood, Krishan

2006-01-01

This article explores a paradox, namely the rhetoric of engagement with diversity and social justice among education leaders, yet the paucity in forward-looking critical theory and practice to develop that engagement. It draws upon relatively new as well as established concepts, including the Capabilities Approach, to suggest how and why diversity…

Do I Really Know You? Do You Really Know Me? Empathy amid Diversity in Differing Learning Contexts

ERIC Educational Resources Information Center

Kasl, Elizabeth; Yorks, Lyle

2016-01-01

We explore the need for empathy in diverse groups, conceptualize the epistemology of empathy in relationship to "whole-person dialogue," and examine strategies for creating empathic space that take into consideration the "paradox of diversity." Two examples from our practice illustrate the role of empathic connection in…

Nomadic-colonial life strategies enable paradoxical survival and growth despite habitat destruction

PubMed Central

Tan, Zong Xuan; Cheong, Kang Hao

2017-01-01

Organisms often exhibit behavioral or phenotypic diversity to improve population fitness in the face of environmental variability. When each behavior or phenotype is individually maladaptive, alternating between these losing strategies can counter-intuitively result in population persistence–an outcome similar to the Parrondo’s paradox. Instead of the capital or history dependence that characterize traditional Parrondo games, most ecological models which exhibit such paradoxical behavior depend on the presence of exogenous environmental variation. Here we present a population model that exhibits Parrondo’s paradox through capital and history-dependent dynamics. Two sub-populations comprise our model: nomads, who live independently without competition or cooperation, and colonists, who engage in competition, cooperation, and long-term habitat destruction. Nomads and colonists may alternate behaviors in response to changes in the colonial habitat. Even when nomadism and colonialism individually lead to extinction, switching between these strategies at the appropriate moments can paradoxically enable both population persistence and long-term growth. DOI: http://dx.doi.org/10.7554/eLife.21673.001 PMID:28084993

Cryptosexuality and the Genetic Diversity Paradox in Coffee Rust, Hemileia vastatrix

PubMed Central

Carvalho, Carlos Roberto; Fernandes, Ronaldo C.; Carvalho, Guilherme Mendes Almeida; Barreto, Robert W.; Evans, Harry C.

2011-01-01

Background Despite the fact that coffee rust was first investigated scientifically more than a century ago, and that the disease is one of the major constraints to coffee production - constantly changing the socio-economic and historical landscape of the crop - critical aspects of the life cycle of the pathogen, Hemileia vastatrix, remain unclear. The asexual urediniospores are regarded as the only functional propagule: theoretically, making H. vastatrix a clonal species. However, the well-documented emergence of new rust pathotypes and the breakdown in genetic resistance of coffee cultivars, present a paradox. Methods and Results Here, using computer-assisted DNA image cytometry, following a modified nuclear stoichiometric staining technique with Feulgen, we show that meiosis occurs within the urediniospores. Stages of spore development were categorised based on morphology, from the spore-mother cell through to the germinating spore, and the relative nuclear DNA content was quantified statistically at each stage. Conclusions Hidden sexual reproduction disguised within the asexual spore (cryptosexuality) could explain why new physiological races have arisen so often and so quickly in Hemileia vastatrix. This could have considerable implications for coffee breeding strategies and may be a common event in rust fungi, especially in related genera occupying the same basal phylogenetic lineages. PMID:22102860

Localization of one-photon state in space and Einstein-Podolsky-Rosen paradox in spontaneous parametric down conversion

NASA Technical Reports Server (NTRS)

Penin, A. N.; Reutova, T. A.; Sergienko, A. V.

1992-01-01

An experiment on one-photon state localization in space using a correlation technique in Spontaneous Parametric Down Conversion (SPDC) process is discussed. Results of measurements demonstrate an idea of the Einstein-Podolsky-Rosen (EPR) paradox for coordinate and momentum variables of photon states. Results of the experiment can be explained with the help of an advanced wave technique. The experiment is based on the idea that two-photon states of optical electromagnetic fields arising in the nonlinear process of the spontaneous parametric down conversion (spontaneous parametric light scattering) can be explained by quantum mechanical theory with the help of a single wave function.

Localization of one-photon state in space and Einstein-Podolsky-Rosen paradox in spontaneous parametric down conversion

NASA Astrophysics Data System (ADS)

Penin, A. N.; Reutova, T. A.; Sergienko, A. V.

1992-02-01

An experiment on one-photon state localization in space using a correlation technique in Spontaneous Parametric Down Conversion (SPDC) process is discussed. Results of measurements demonstrate an idea of the Einstein-Podolsky-Rosen (EPR) paradox for coordinate and momentum variables of photon states. Results of the experiment can be explained with the help of an advanced wave technique. The experiment is based on the idea that two-photon states of optical electromagnetic fields arising in the nonlinear process of the spontaneous parametric down conversion (spontaneous parametric light scattering) can be explained by quantum mechanical theory with the help of a single wave function.

Design principles of paradoxical signaling in the immune system

NASA Astrophysics Data System (ADS)

Hart, Yuval

A widespread feature of cell-cell signaling systems is paradoxical pleiotropy: the same secreted signaling molecule can induce opposite effects in the responding cells. For example, the cytokine IL-2 can promote proliferation and death of T-cells. The role of such paradoxical signaling remains unclear. We suggest that this mechanism provides homeostatic concentration of cells, independent of initial conditions. The crux of the paradoxical mechanism is the combination of a positive and a negative feedback loops creating two stable states - an OFF state and an ON state. Experimentally, we found that CD4 + cells grown in culture with a 30-fold difference in initial concentrations reached a homeostatic concentration nearly independent of initial cell levels (ON-state). Below an initial threshold, cell density decayed to extinction (OFF-state). Mathematical modeling explained the observed cell and cytokine dynamics and predicted conditions that shifted cell fate from homeostasis to the OFF-state. We suggest that paradoxical signaling provides cell circuits with specific dynamical features that are robust to environmental perturbations.

The effect of smoking on lung cancer: ethnic differences and the smoking paradox

PubMed Central

2016-01-01

The objectives of this review were to determine whether the smoking paradox still exists and to summarize possible explanations for the smoking paradox. Based on published data, we compared the risk of cigarette smoking for lung cancer in Western and Asian countries. We extracted data from the relevant studies about annual tobacco consumption, lung cancer mortality rates according to smoking status from each country, and possible explanations for the smoking paradox. A significantly greater risk of lung cancer death was found among current smokers in Asian countries than among nonsmokers, with relative risks (RRs) of 4.0 to 4.6 for Koreans, 3.7 to 5.1 for Japanese, and 2.4 to 6.5 for Chinese. Although a significantly greater risk of lung cancer was present among current smokers in Asian countries, the RRs in Asian countries were much lower than those reported in Western countries (range, 9.4 to 23.2). Possible explanations for the smoking paradox included epidemiologic characteristics, such as the smoking amount, age at smoking initiation, and the use of filtered or mild tobacco. The smoking paradox definitely exists, but may be explained by major epidemiologic characteristics. Therefore, the smoking paradox should not be interpreted as indicating that tobacco is safer or less harmful for Asians. PMID:28092929

Diverse Local Literacies and Standardizing Policies

ERIC Educational Resources Information Center

Bomer, Randy; Maloch, Beth

2012-01-01

The authors challenge educators to speculate on how to address local issues in a world that is increasingly diverse and global. This Research and Policy section emphasizes the seemingly paradoxical importance of both local and global literacy, illuminating the tension between the preservation of local literacy and a global standardization of…

Achieving Administrative Diversity. New Directions for Community Colleges, Number 94.

ERIC Educational Resources Information Center

Bowen, Raymond C., Ed.; Muller, Gilbert H., Ed.

1996-01-01

Focusing on the challenge of expanding administrative opportunities for minorities, the 10 essays in this volume explore the problem of underrepresentation of minority administrators at community colleges and suggest strategies for improving diversity. The following articles are provided: (1) "Paradox and Promise: Leadership and the Neglected…

HIV As Trojan Exosome: Immunological Paradox Explained?

PubMed

Hildreth, James E K

2017-01-01

The HIV pandemic is still a major global challenge, despite the widespread availability of antiretroviral drugs. An effective vaccine would be the ideal approach to bringing the pandemic to an end. However, developing an effective HIV vaccine has proven to be an elusive goal. Three major human HIV vaccine trials revealed a strong trend toward greater risk of infection among vaccine recipients versus controls. A similar observation was made in a macaque SIV vaccine study. The mechanism explaining this phenomenon is not known. Here, a model is presented that may explain the troubling results of vaccine studies and an immunological paradox of HIV pathogenesis: preferential infection of HIV-specific T cells. The central hypothesis of this perspective is that as "Trojan exosomes" HIV particles can directly activate HIV-specific T cells enhancing their susceptibility to infection. Understanding the biology of HIV as an exosome may provide insights that enable novel approaches to vaccine development.

Life in the salinity gradient: Discovering mechanisms behind a new biodiversity pattern

NASA Astrophysics Data System (ADS)

Telesh, Irena; Schubert, Hendrik; Skarlato, Sergei

2013-12-01

A recently discovered paradoxical maximum of planktonic protistan species in the salinity gradient of the Baltic Sea revealed an inverse trend of species number/salinity relation in comparison to the previously accepted species-minimum model for macrozoobenthos. Here, we review long-term data on organisms of different size classes and ecological groups to show that eukaryotic and prokaryotic microbes in plankton demonstrate a maximum species richness in the challenging zone of the critical salinity 5-8, where the large-bodied bottom dwellers (macrozoobenthos, macroalgae and aquatic higher plants) experience large-scale salinity stress which leads to an impoverished diversity. We propose a new conceptual model to explain why the diversity of small, fast-developing, rapidly evolving unicellular plankton organisms benefits from relative vacancy of brackish-water ecological niches and impaired competitiveness therein. The ecotone theory, Hutchinson's Ecological Niche Concept, species-area relationships and the Intermediate Disturbance Hypothesis are considered as a theoretical framework for understanding extinctions, speciation and variations in the evolution rates of different aquatic species in ecosystems with the pronounced salinity gradient.

Reverse epidemiology beyond dialysis patients: chronic heart failure, geriatrics, rheumatoid arthritis, COPD, and AIDS.

PubMed

Horwich, Tamara B; Fonarow, Gregg C

2007-01-01

"Reverse epidemiology" refers to paradoxical and counterintuitive epidemiologic associations between survival outcomes and traditional cardiovascular risk factors such as obesity, high blood pressure, and high cholesterol. Reverse epidemiology has been well described in end stage renal disease, but also has been observed in chronic disease states, including chronic heart failure, rheumatoid arthritis, chronic obstructive pulmonary disease, and Acquired Immune Deficiency Syndrome, and in elderly populations. This review will highlight the recent medical literature on reverse epidemiology in these populations. Common pathophysiologic underpinnings in these chronic disease states may help explain the reversal of risk factors observed in these diverse populations. Furthermore, guidelines for the general population for optimal goals of weight, cholesterol levels, and blood pressure may not apply to special populations, including patients with chronic diseases or elderly persons.

Why We Must Continue to Investigate Menthol's Role in the African American Smoking Paradox.

PubMed

Alexander, Linda A; Trinidad, Dennis R; Sakuma, Kari-Lyn K; Pokhrel, Pallav; Herzog, Thaddeus A; Clanton, Mark S; Moolchan, Eric T; Fagan, Pebbles

2016-04-01

The disproportionate burden of tobacco use among African Americans is largely unexplained. The unexplained disparities, referred to as the African American smoking paradox, includes several phenomena. Despite their social disadvantage, African American youth have lower smoking prevalence rates, initiate smoking at older ages, and during adulthood, smoking rates are comparable to whites. Smoking frequency and intensity among African American youth and adults are lower compared to whites and American Indian and Alaska Natives, but tobacco-caused morbidity and mortality rates are disproportionately higher. Disease prediction models have not explained disease causal pathways in African Americans. It has been hypothesized that menthol cigarette smoking, which is disproportionately high among African Americans, may help to explain several components of the African American smoking paradox. This article provides an overview of the potential role that menthol plays in the African American smoking paradox. We also discuss the research needed to better understand this unresolved puzzle. We examined prior synthesis reports and reviewed the literature in PubMed on the menthol compound and menthol cigarette smoking in African Americans. The pharmacological and physiological effects of menthol and their interaction with biological and genetic factors may indirectly contribute to the disproportionate burden of cigarette use and diseases among African Americans. Future studies that examine taste sensitivity, the menthol compound, and their effects on smoking and chronic disease would provide valuable information on how to reduce the tobacco burden among African Americans. Our study highlights four counterintuitive observations related to the smoking risk profiles and chronic disease outcomes among African Americans. The extant literature provides strong evidence of their existence and shows that long-standing paradoxes have been largely unaffected by changes in the social environment. African Americans smoke menthols disproportionately, and menthol's role in the African American smoking paradox has not been thoroughly explored. We propose discrete hypotheses that will help to explain the phenomena and encourage researchers to empirically test menthol's role in smoking initiation, transitions to regular smoking and chronic disease outcomes in African Americans. © The Author 2016. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

[H2O ortho-para spin conversion in aqueous solutions as a quantum factor of Konovalov paradox].

PubMed

Pershin, S M

2014-01-01

Recently academician Konovalov and co-workers observed an increase in electroconductivity and biological activity simultaneously with diffusion slowing (or nanoobject diameter increasing) and extremes of other parameters (ζ-potential, surface tension, pH, optical activity) in low concentration aqueous solutions. This phenomenon completely disappeared when samples were shielded against external electromagnetic fields by a Faraday cage. A conventional theory of water and water solutions couldn't explain "Konovalov paradox" observed in numerous experiments (representative sampling about 60 samples and 7 parameters). The new approach was suggested to describe the physics of water and explain "Konovalov paradox". The proposed concept takes into account the quantum differences of ortho-para spin isomers of H2O in bulk water (rotational spin-selectivity upon hydration and spontaneous formation of ice-like structures, quantum beats and spin conversion induced in the presence of a resonant electromagnetic radiation). A size-dependent self-assembly of amorphous complexes of H2O molecules more than 275 leading to the ice Ih structure observed in the previous experiments supports this concept.

Crozier's paradox revisited: maintenance of genetic recognition systems by disassortative mating.

PubMed

Holman, Luke; van Zweden, Jelle S; Linksvayer, Timothy A; d'Ettorre, Patrizia

2013-09-27

Organisms are predicted to behave more favourably towards relatives, and kin-biased cooperation has been found in all domains of life from bacteria to vertebrates. Cooperation based on genetic recognition cues is paradoxical because it disproportionately benefits individuals with common phenotypes, which should erode the required cue polymorphism. Theoretical models suggest that many recognition loci likely have some secondary function that is subject to diversifying selection, keeping them variable. Here, we use individual-based simulations to investigate the hypothesis that the dual use of recognition cues to facilitate social behaviour and disassortative mating (e.g. for inbreeding avoidance) can maintain cue diversity over evolutionary time. Our model shows that when organisms mate disassortatively with respect to their recognition cues, cooperation and recognition locus diversity can persist at high values, especially when outcrossed matings produce more surviving offspring. Mating system affects cue diversity via at least four distinct mechanisms, and its effects interact with other parameters such as population structure. Also, the attrition of cue diversity is less rapid when cooperation does not require an exact cue match. Using a literature review, we show that there is abundant empirical evidence that heritable recognition cues are simultaneously used in social and sexual behaviour. Our models show that mate choice is one possible resolution of the paradox of genetic kin recognition, and the literature review suggests that genetic recognition cues simultaneously inform assortative cooperation and disassortative mating in a large range of taxa. However, direct evidence is scant and there is substantial scope for future work.

How Employees Remain Happy: Explaining a Paradox

ERIC Educational Resources Information Center

Hutton, Dorothy M.; Atkinson, Barbara; Judd, Priya; Darling, Julie; Tran, Linh; Cummins, Robert A.

2004-01-01

This paper draws on subjective quality of life theory to explain findings from three studies of quality of work life. The studies were conducted with 346 regional process workers, metropolitan employment officers and nurses. The results support the adoption of the theory of homeostasis as an explanation for findings on subjective wellbeing at work…

Scientific progress specific to biology: an epistemological overview.

PubMed

Durrive, Barthélemy

2012-09-01

Progresses in leading edge life sciences are undeniable, but there is more to it: from an epistemological perspective, they rest on a paradox vitalizing the very project of biology. Making our understanding of organic functioning all the more objective, life sciences yet exploit a paradigm which structurally rules out any opportunity to explain why biological phenomena are explainable the way we claim they are. As such a blind spot is constitutive of the disciplinary boundaries that condition and permit objective modelling, evolutions in scientists' mode of thought (i.e. paradigm shifts) may require at crucial points some interaction with epistemologists or historians of sciences. The model case of ontophylogenesis thus shows not only how such cooperation can be useful (both in normal science and in transitional contexts), but mostly why it plays a role in helping biology to get out of its intrinsic paradox. The most innovative feature of ontophylogenesis would thus be the following: to give account for the mode of intelligibility it chose by explaining it - in a truly Darwinian manner -in the core of the theory. Though this epistemic move definitely confirms biology to be an autonomous science as long as it faces its constitutive paradox, the methodological detour such realization implied would go through occasional interplay with "exclusively reflexive approaches" - that is to say, humanities. Copyright © 2012 Elsevier Ltd. All rights reserved.

A Postulated Mechanism That Leads to Materialization and Dematerialization of Matter and to Antigravity.

ERIC Educational Resources Information Center

Bearden, Thomas E.

This document presents a discussion of the postulated mechanism that leads to the materialization and dematerialization of matter and to antigravity. The mechanism also explains why an orbital electron does not radiate energy, in contradiction to classical electromagnetic theory. One of the paradoxes of special relativity is explained. A new model…

A postulated mechanism that leads to materialization and dematerialization of matter and to antigravity. Technical report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bearden, T.E.

1975-10-08

This report presents a discussion of the postulated mechanism that leads to the materialization and dematerialization of matter and to antigravity. The mechanism also explains why an orbital electron does not radiate energy, in contradiction to classical electromagnetic theory. One of the paradoxes of special relativity is explained. A new model of a photon is advanced. The relativistic increase of mass with velocity is explained. (GRA)

Light Stable Isotopic Compositions of Enriched Mantle Sources: Resolving the Dehydration Paradox

NASA Astrophysics Data System (ADS)

Dixon, J. E.; Bindeman, I. N.; Kingsley, R. H.

2017-12-01

An outstanding puzzle in mantle geochemistry has been the origin and evolution of Earth's volatile components. The "dehydration paradox" refers to the following conundrum. Mantle compositions for some enriched mid-ocean ridge (MORB) and ocean island (OIB) basalts basalts require involvement of a mostly dehydrated slab component to explain the trace element ratios and radiogenic isotopic compositions, but a fully hydrated slab component to explain the stable isotopic compositions. Volatile and stable isotopic data on enriched MORB show a diversity of enriched components. Pacific PREMA-type basalts (H2O/Ce = 215 ± 30, δDSMOW = -45 ± 5 ‰) are similar to those in the north Atlantic (H2O/Ce = 220 ± 30; δDSMOW = -30 to -40 ‰). Basalts with EM-type signatures have regionally variable volatile compositions. North Atlantic EM-type basalts are wetter (H2O/Ce = 330 ± 30) and have isotopically heavier hydrogen (δDSMOW = -57 ± 5 ‰) than north Atlantic MORB. South Atlantic EM-type basalts are damp (H2O/Ce = 120 ± 10) with intermediate δDSMOW (-68 ± 2 ‰), similar to dDSMOW for Pacific MORB. North EPR EM-type basalts are dry (H2O/Ce = 110 ± 20) and isotopically light (δDSMOW = -94 ± 3 ‰). Boron and lithium isotopic ratios parallel the trends observed for dDSMOW. A multi-stage metasomatic and melting model accounts for the origin of the enriched components by extending the subduction factory concept down through the mantle transition zone, with slab temperature a key variable. The dehydration paradox is resolved by decoupling of volatiles from lithophile elements, reflecting primary dehydration of the slab followed by secondary rehydration and re-equilibration by fluids derived from subcrustal hydrous phases (e.g., antigorite) in cooler, deeper parts of the slab. The "expanded subduction factory" model includes melting at several key depths, including 1) 180 to 280 km, where EM-type mantle compositions are generated above slabs with average to hot thermal profiles by addition of <1% carbonated sediment-derived supercritical fluids/melts to depleted asthenospheric or subcontinental lithospheric mantle, and 2) 410 to 660 km, where PREMA-type mantle sources are generated, above slabs with average to cool thermal profiles, by addition of <1% carbonated eclogite ± sediment-derived supercritical fluids to depleted mantle.

Feminist activist women are masculinized in terms of digit-ratio and social dominance: a possible explanation for the feminist paradox.

PubMed

Madison, Guy; Aasa, Ulrika; Wallert, John; Woodley, Michael A

2014-01-01

The feminist movement purports to improve conditions for women, and yet only a minority of women in modern societies self-identify as feminists. This is known as the feminist paradox. It has been suggested that feminists exhibit both physiological and psychological characteristics associated with heightened masculinization, which may predispose women for heightened competitiveness, sex-atypical behaviors, and belief in the interchangeability of sex roles. If feminist activists, i.e., those that manufacture the public image of feminism, are indeed masculinized relative to women in general, this might explain why the views and preferences of these two groups are at variance with each other. We measured the 2D:4D digit ratios (collected from both hands) and a personality trait known as dominance (measured with the Directiveness scale) in a sample of women attending a feminist conference. The sample exhibited significantly more masculine 2D:4D and higher dominance ratings than comparison samples representative of women in general, and these variables were furthermore positively correlated for both hands. The feminist paradox might thus to some extent be explained by biological differences between women in general and the activist women who formulate the feminist agenda.

Making Games Not Work: Paradoxes Embedded in Game-Based Training and Concepts for Overcoming Them

NASA Technical Reports Server (NTRS)

Jones, Phillip N.; Cuper, Taryn

2010-01-01

An interest in game-based training solutions is natural. All one has to do is watch someone fully engaged in a modern game to see the potential of harnessing that attention for training. However, the reality of game-based training has not fully satisfied these expectations. This paper explains two paradoxes that must be overcome for games to support training. These paradoxes are a result of the realities of the basic human condition clashing with the requirements of learning theory. 80th paradoxes arise from the concept of "engagement" that is central to games. The first comes from a more robust definition of engagement, which is the condition of Flow or Optimal Experience. Flow is the state game developers want to see in users. One aspect of Flow is loss of sense of self as the individual becomes immersed in the experience. The paradox arises because this loss of self directly contradicts the learning requirement of self-reflection. The second paradox comes from theories of play, which state in part that play requires a level of individual freedom. The contradiction arises when game-based play must be harnessed to an organizational training program or regimen. The paper will discuss these paradoxes in the context of an effort to design a game-based training modality to train combat medics and will close with a review of compensating strategies identified by the designers. The paper will provide information important to anyone interested in conceptualizing and designing game-based training.

The management of cryptogenic stroke in pregnancy

PubMed Central

Orchard, E A; Wilson, N; Ormerod, O J M

2011-01-01

Cerebrovascular accidents (CVAs) during pregnancy are uncommon but can have devastating consequences. The causes of CVA in both the pregnant and the non-pregnant state are diverse and require thorough investigation. Recent studies have indicated that embolic stroke in young adults may be caused by paradoxical emboli through a patent foramen ovale (PFO), suggesting that the presence of a PFO should be specifically sought in pregnant or postpartum women presenting with CVA. This review will outline the causes of CVAs in pregnancy and the role of paradoxical emboli, with a focus on PFO. PMID:27579087

Biotic Interactions Shape the Ecological Distributions of Staphylococcus Species.

PubMed

Kastman, Erik K; Kamelamela, Noelani; Norville, Josh W; Cosetta, Casey M; Dutton, Rachel J; Wolfe, Benjamin E

2016-10-18

Many metagenomic sequencing studies have observed the presence of closely related bacterial species or genotypes in the same microbiome. Previous attempts to explain these patterns of microdiversity have focused on the abiotic environment, but few have considered how biotic interactions could drive patterns of microbiome diversity. We dissected the patterns, processes, and mechanisms shaping the ecological distributions of three closely related Staphylococcus species in cheese rind biofilms. Paradoxically, the most abundant species (S. equorum) is the slowest colonizer and weakest competitor based on growth and competition assays in the laboratory. Through in vitro community reconstructions, we determined that biotic interactions with neighboring fungi help resolve this paradox. Species-specific stimulation of the poor competitor by fungi of the genus Scopulariopsis allows S. equorum to dominate communities in vitro as it does in situ Results of comparative genomic and transcriptomic experiments indicate that iron utilization pathways, including a homolog of the S. aureus staphyloferrin B siderophore operon pathway, are potential molecular mechanisms underlying Staphylococcus-Scopulariopsis interactions. Our integrated approach demonstrates that fungi can structure the ecological distributions of closely related bacterial species, and the data highlight the importance of bacterium-fungus interactions in attempts to design and manipulate microbiomes. Decades of culture-based studies and more recent metagenomic studies have demonstrated that bacterial species in agriculture, medicine, industry, and nature are unevenly distributed across time and space. The ecological processes and molecular mechanisms that shape these distributions are not well understood because it is challenging to connect in situ patterns of diversity with mechanistic in vitro studies in the laboratory. Using tractable cheese rind biofilms and a focus on coagulase-negative staphylococcus (CNS) species, we demonstrate that fungi can mediate the ecological distributions of closely related bacterial species. One of the Staphylococcus species studied, S. saprophyticus, is a common cause of urinary tract infections. By identifying processes that control the abundance of undesirable CNS species, cheese producers will have more precise control on the safety and quality of their products. More generally, Staphylococcus species frequently co-occur with fungi in mammalian microbiomes, and similar bacterium-fungus interactions may structure bacterial diversity in these systems. Copyright © 2016 Kastman et al.

Enceladus-Mimas paradox: a result of different early evolutions of satellites?

NASA Astrophysics Data System (ADS)

Czechowski, L.; Witek, P.

2015-10-01

Thermal history of Mimas and Enceladus is investigated from the beginning of accretion to 400 Myr. The following heat sources are included: short lived and long lived radioactive isotopes, accretion,serpentinization, and phase changes. We find that temperature of Mimas' interior was significantly lower than of Enceladus. Comparison of thermal models of Mimas and Enceladus indicates that conditions favorable for starting tidal heating lasted for short time (~10 7 yr) in Mimas and for ~10 8 yr in Enceladus. This could explain Mimas- Enceladus paradox.

Can Metabolic Mechanisms of Stem Cell Maintenance Explain Aging and the Immortal Germline?

PubMed

Snoeck, Hans-Willem

2015-06-04

The mechanisms underlying the aging process are not understood. Even tissues endowed with somatic stem cells age while the germline appears immortal. I propose that this paradox may be explained by the pervasive use of glycolysis by somatic stem cells as opposed to the predominance of mitochondrial respiration in gametes. Copyright © 2015 Elsevier Inc. All rights reserved.

Personalisation: A Theoretical Possibility to Reinvigorate Children's Interest in Storybook Reading and Facilitate Greater Book Diversity

ERIC Educational Resources Information Center

Kucirkova, Natalia

2016-01-01

Since the early 2010s, there has been a proliferation of new platforms for children's stories (e.g. storybook apps or iBooks), but not necessarily greater diversity of story content or children's greater interest in reading. This article argues for a new approach to address the apparent paradox of a wider availability of children's literature…

Explaining seemingly paradoxical consumer experiences: conjoining weekly road rage and church attendance.

PubMed

Gau, Li-Shiue; Woodside, Arch G; Martin, Drew

2015-02-01

The purposes of the current study are threefold: Provide evidence that an extreme paradoxical group exists-people frequently attending church and exhibiting road rage, profile this group, and frame possible explanations for the seemingly paradoxical behaviors. This study employs data from a national (USA) lifestyle survey conducted by Market Facts with 3,350 American respondents. The major questions asked about church participation and road-rage behavior ("giving a finger" and "flashing headlights"). Nomologically, relevant activities include 3 items for church goers and 3 items for road-rage givers. Additionally, 14 items profiled the lifestyles of the unique paradoxical behavior segment. Utilizing cross-tabulation tables, property space analyses identify the double extreme (XX) group (18 people) and other 6 groups with a significant chi-square test, confirming the extreme group exists. Analyses of variance test results show that comparing nomologically relevant activities among the seven groups is all statistically significant, indicating the nomological validity is met. Overall, the XX group tends to have more males, be younger, and have a higher proportion of people working in sales. The profile of lifestyle analyses shows the XX group members have both high ambitions and expectations, might be very frustrated individuals, and equip with the adventurous and masculine traits related to aggression. The XX behavior group's demographic and psychographic characteristics portray similar lifestyles that differ from other groups. Case-based analyses provide further contextual information of nuances to XX segment individuals. The limited energy theory, the Eagleman's theory of unconscious mind, and justification theory help to explain why people conjointly go to church and commit road rage. Addressing chronic paradoxical behaviors provides implications for social de-marketing to reduce aggressive anti-social behavior such as road rage. Frequent church attendance may help make people more sensitive to their wrongdoings and gradually revise the anti-social behavior.

Salience driven value integration explains decision biases and preference reversal

PubMed Central

Tsetsos, Konstantinos; Chater, Nick; Usher, Marius

2012-01-01

Human choice behavior exhibits many paradoxical and challenging patterns. Traditional explanations focus on how values are represented, but little is known about how values are integrated. Here we outline a psychophysical task for value integration that can be used as a window on high-level, multiattribute decisions. Participants choose between alternative rapidly presented streams of numerical values. By controlling the temporal distribution of the values, we demonstrate that this process underlies many puzzling choice paradoxes, such as temporal, risk, and framing biases, as well as preference reversals. These phenomena can be explained by a simple mechanism based on the integration of values, weighted by their salience. The salience of a sampled value depends on its temporal order and momentary rank in the decision context, whereas the direction of the weighting is determined by the task framing. We show that many known choice anomalies may arise from the microstructure of the value integration process. PMID:22635271

RECONCILING AGN-STAR FORMATION, THE SOLTAN ARGUMENT, AND MEIER’S PARADOX

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garofalo, David; Kim, Matthew I.; Christian, Damian J.

2016-02-01

We provide a theoretical context for understanding the recent work of Kalfountzou et al. showing that star formation is enhanced at lower optical luminosity in radio-loud quasars. Our proposal for coupling the assumption of collimated FRII quasar-jet-induced star formation with lower accretion optical luminosity also explains the observed jet power peak in active galaxies at higher redshift compared to the peak in accretion power, doing so in a way that predicts the existence of a family of radio-quiet active galactic nuclei associated with rapidly spinning supermassive black holes at low redshift, as mounting observations suggest. The relevance of this work liesmore » in its promise to explain the observed cosmological evolution of accretion power, jet power, and star formation in a way that is both compatible with the Soltan argument and resolves the so-called “Meier Paradox.”.« less

Feminist activist women are masculinized in terms of digit-ratio and social dominance: a possible explanation for the feminist paradox

PubMed Central

Madison, Guy; Aasa, Ulrika; Wallert, John; Woodley, Michael A.

2014-01-01

The feminist movement purports to improve conditions for women, and yet only a minority of women in modern societies self-identify as feminists. This is known as the feminist paradox. It has been suggested that feminists exhibit both physiological and psychological characteristics associated with heightened masculinization, which may predispose women for heightened competitiveness, sex-atypical behaviors, and belief in the interchangeability of sex roles. If feminist activists, i.e., those that manufacture the public image of feminism, are indeed masculinized relative to women in general, this might explain why the views and preferences of these two groups are at variance with each other. We measured the 2D:4D digit ratios (collected from both hands) and a personality trait known as dominance (measured with the Directiveness scale) in a sample of women attending a feminist conference. The sample exhibited significantly more masculine 2D:4D and higher dominance ratings than comparison samples representative of women in general, and these variables were furthermore positively correlated for both hands. The feminist paradox might thus to some extent be explained by biological differences between women in general and the activist women who formulate the feminist agenda. PMID:25250010

The Parana paradox: can a model explain the decadal impacts of climate variability and land-cover change?

NASA Astrophysics Data System (ADS)

Lee, E.; Moorcroft, P. R.; Livino, A.; Briscoe, J.

2013-12-01

Since the 1970s, despite a decrease in rainfall, flow in the Parana river has increased. This paradox is explored using the Ecosystem Demography (ED) model. If there were no change in land cover, the modeled runoff decreased from the 1970s to the 2000s by 11.8% (with 1970 land cover) or 18.8% (with 2008 land cover). When the model is run holding climate constant, the decadal average of the modeled runoff increased by 24.4% (with the 1970s climate) or by 33.6% (with 2000s climate). When the model is run allowing both the actual climate and land-cover changes, the model gives an increase in the decadal average of runoff by 8.5%. This agrees well with 10.5% increase in the actual stream flow as measured at Itaipu. There are three main conclusions from this work. First, the ED model is able to explain a major, paradoxical, reality in the Parana basin. Second, it is necessary to take into account both climate and land use changes when exploring past or future changes in river flows. Third, the ED model, now coupled with a regional climate model (i.e., EDBRAMS), is a sound basis for exploring likely changes in river flows in major South American rivers.

Braess's paradox in epidemic game: better condition results in less payoff.

PubMed

Zhang, Hai-Feng; Yang, Zimo; Wu, Zhi-Xi; Wang, Bing-Hong; Zhou, Tao

2013-11-21

Facing the threats of infectious diseases, we take various actions to protect ourselves, but few studies considered an evolving system with competing strategies. In view of that, we propose an evolutionary epidemic model coupled with human behaviors, where individuals have three strategies: vaccination, self-protection and laissez faire, and could adjust their strategies according to their neighbors' strategies and payoffs at the beginning of each new season of epidemic spreading. We found a counter-intuitive phenomenon analogous to the well-known Braess's Paradox, namely a better condition may lead to worse performance. Specifically speaking, increasing the successful rate of self-protection does not necessarily reduce the epidemic size or improve the system payoff. The range and degree of the Braess's Paradox are sensitive to both the parameters characterizing the epidemic spreading and the strategy payoff, while the existence of the Braess's Paradox is insensitive to the network topologies. This phenomenon can be well explained by a mean-field approximation. Our study demonstrates an important fact that a better condition for individuals may yield a worse outcome for the society.

Desire versus Efficacy in Smokers’ Paradoxical Reactions to Pictorial Health Warnings for Cigarettes

PubMed Central

Romer, Daniel; Peters, Ellen; Strasser, Andrew A.; Langleben, Daniel

2013-01-01

Pictorial health warnings on cigarette packs create aversive emotional reactions to smoking and induce thoughts about quitting; however, contrary to models of health behavior change, they do not appear to alter intentions to quit smoking. We propose and test a novel model of intention to quit an addictive habit such as smoking (the efficacy-desire model) that can explain this paradoxical effect. At the core of the model is the prediction that self-efficacy and desire to quit an addictive habit are inversely related. We tested the model in an online experiment that randomly exposed smokers (N = 3297) to a cigarette pack with one of three increasing levels of warning intensity. The results supported the model’s prediction that despite the effects of warnings on aversion to smoking, intention to quit smoking is an inverted U-shape function of the smoker’s self-efficacy for quitting. In addition, smokers with greater (lesser) quit efficacy relative to smoking efficacy increase (decrease) intentions to quit. The findings show that previous failures to observe effects of pictorial warning labels on quit intentions can be explained by the contradictory individual differences that warnings produce. Thus, the model explains the paradoxical finding that quit intentions do not change at the population level, even though smokers recognize the implications of warnings. The model suggests that pictorial warnings are effective for smokers with stronger quit-efficacy beliefs and provides guidance for how cigarette warnings and tobacco control strategies can be designed to help smokers quit. PMID:23383006

Saddle Pulmonary Embolism with Paradoxical Coronary Artery Embolism through a Patent Foramen Ovale.

PubMed

Achesinski, Amber L; Gunther, Wendy M; Pearman, Catherine B

2017-05-01

A 35-year-old male patient was found in cardiac arrest in his vehicle, with no apparent injuries after a minor motor vehicle collision. The decedent was found to have a saddle pulmonary embolus with a thromboembolus impacted across a patent foramen ovale and a paradoxical embolism in the circumflex coronary artery, as well as significant clotting in the deep veins of both lower extremities. There were no risk factors in his history to explain the deep venous thrombosis; family history suggested the possibility of an unrecognized clotting disorder. © 2017 American Academy of Forensic Sciences.

Hypocalcemia-Induced Seizure

PubMed Central

Trinidad, Bradley J.; Shi, Jiong

2015-01-01

Calcium is essential for both neurotransmitter release and muscle contraction. Given these important physiological processes, it seems reasonable to assume that hypocalcemia may lead to reduced neuromuscular excitability. Counterintuitively, however, clinical observation has frequently documented hypocalcemia’s role in induction of seizures and general excitability processes such as tetany, Chvostek’s sign, and bronchospasm. The mechanism of this calcium paradox remains elusive, and very few pathophysiological studies have addressed this conundrum. Nevertheless, several studies primarily addressing other biophysical issues have provided some clues. In this review, we analyze the data of these studies and propose an integrative model to explain this hypocalcemic paradox. PMID:25810356

Gut Microbiota and the Paradox of Cancer Immunotherapy

PubMed Central

Poutahidis, Theofilos; Kleinewietfeld, Markus; Erdman, Susan E.

2014-01-01

It is recently shown that beneficial environmental microbes stimulate integrated immune and neuroendocrine factors throughout the body, consequently modulating regulatory T-lymphocyte phenotypes, maintaining systemic immune balance, and determining the fate of preneoplastic lesions toward regression while sustaining whole body good health. Stimulated by a gut microbiota-centric systemic homeostasis hypothesis, we set out to explore the influence of the gut microbiome to explain the paradoxical roles of regulatory T-lymphocytes in cancer development and growth. This paradigm shift places cancer prevention and treatment into a new broader context of holobiont engineering to cultivate a tumor-suppressive macroenvironment. PMID:24778636

Gut microbiota and the paradox of cancer immunotherapy.

PubMed

Poutahidis, Theofilos; Kleinewietfeld, Markus; Erdman, Susan E

2014-01-01

It is recently shown that beneficial environmental microbes stimulate integrated immune and neuroendocrine factors throughout the body, consequently modulating regulatory T-lymphocyte phenotypes, maintaining systemic immune balance, and determining the fate of preneoplastic lesions toward regression while sustaining whole body good health. Stimulated by a gut microbiota-centric systemic homeostasis hypothesis, we set out to explore the influence of the gut microbiome to explain the paradoxical roles of regulatory T-lymphocytes in cancer development and growth. This paradigm shift places cancer prevention and treatment into a new broader context of holobiont engineering to cultivate a tumor-suppressive macroenvironment.

Resolving the evolutionary paradox of genetic instability: a cost-benefit analysis of DNA repair in changing environments.

PubMed

Breivik, Jarle; Gaudernack, Gustav

2004-04-09

Loss of genetic stability is a critical phenomenon in cancer and antibiotic resistance, and the prevailing dogma is that unstable cells survive because instability provides adaptive mutations. Challenging this view, we have argued that genetic instability arises because DNA repair may be a counterproductive strategy in mutagenic environments. This paradoxical relationship has also been confirmed by explicit experiments, but the underlying evolutionary principles remain controversial. This paper aims to clarify the issue, and presents a model that explains genetic instability from the basic perspective of molecular evolution and information processing.

Molecular pathological epidemiology gives clues to paradoxical findings.

PubMed

Nishihara, Reiko; VanderWeele, Tyler J; Shibuya, Kenji; Mittleman, Murray A; Wang, Molin; Field, Alison E; Giovannucci, Edward; Lochhead, Paul; Ogino, Shuji

2015-10-01

A number of epidemiologic studies have described what appear to be paradoxical associations, where an incongruous relationship is observed between a certain well-established risk factor for disease incidence and favorable clinical outcome among patients with that disease. For example, the "obesity paradox" represents the association between obesity and better survival among patients with a certain disease such as coronary heart disease. Paradoxical observations cause vexing clinical and public health problems as they raise questions on causal relationships and hinder the development of effective interventions. Compelling evidence indicates that pathogenic processes encompass molecular alterations within cells and the microenvironment, influenced by various exogenous and endogenous exposures, and that interpersonal heterogeneity in molecular pathology and pathophysiology exists among patients with any given disease. In this article, we introduce methods of the emerging integrative interdisciplinary field of molecular pathological epidemiology (MPE), which is founded on the unique disease principle and disease continuum theory. We analyze and decipher apparent paradoxical findings, utilizing the MPE approach and available literature data on tumor somatic genetic and epigenetic characteristics. Through our analyses in colorectal cancer, renal cell carcinoma, and glioblastoma (malignant brain tumor), we can readily explain paradoxical associations between disease risk factors and better prognosis among disease patients. The MPE paradigm and approach can be applied to not only neoplasms but also various non-neoplastic diseases where there exists indisputable ubiquitous heterogeneity of pathogenesis and molecular pathology. The MPE paradigm including consideration of disease heterogeneity plays an essential role in advancements of precision medicine and public health.

Switzerland and Its Educational System: From Babylon zu Multiculturalism.

ERIC Educational Resources Information Center

Allemann-Ghionda, Cristina

1994-01-01

Discusses the paradoxes of the current policies toward multiculturalism and multilingualism in Switzerland. Asserts that policy perspectives lean toward diversity rather than assimilation. Proposes options for an educational concept in a linguistically and culturally plural Switzerland, embedded in Europe. (CFR)

An oligotrophic deep-subsurface community dependent on syntrophy is dominated by sulfur-driven autotrophic denitrifiers

PubMed Central

Kieft, Thomas L.; Kuloyo, Olukayode; Linage-Alvarez, Borja; van Heerden, Esta; Lindsay, Melody R.; Magnabosco, Cara; Wang, Wei; Wiggins, Jessica B.; Guo, Ling; Perlman, David H.; Kyin, Saw; Shwe, Henry H.; Harris, Rachel L.; Oh, Youmi; Yi, Min Joo; Purtschert, Roland; Slater, Greg F.; Ono, Shuhei; Wei, Siwen; Li, Long; Sherwood Lollar, Barbara; Onstott, Tullis C.

2016-01-01

Subsurface lithoautotrophic microbial ecosystems (SLiMEs) under oligotrophic conditions are typically supported by H2. Methanogens and sulfate reducers, and the respective energy processes, are thought to be the dominant players and have been the research foci. Recent investigations showed that, in some deep, fluid-filled fractures in the Witwatersrand Basin, South Africa, methanogens contribute <5% of the total DNA and appear to produce sufficient CH4 to support the rest of the diverse community. This paradoxical situation reflects our lack of knowledge about the in situ metabolic diversity and the overall ecological trophic structure of SLiMEs. Here, we show the active metabolic processes and interactions in one of these communities by combining metatranscriptomic assemblies, metaproteomic and stable isotopic data, and thermodynamic modeling. Dominating the active community are four autotrophic β-proteobacterial genera that are capable of oxidizing sulfur by denitrification, a process that was previously unnoticed in the deep subsurface. They co-occur with sulfate reducers, anaerobic methane oxidizers, and methanogens, which each comprise <5% of the total community. Syntrophic interactions between these microbial groups remove thermodynamic bottlenecks and enable diverse metabolic reactions to occur under the oligotrophic conditions that dominate in the subsurface. The dominance of sulfur oxidizers is explained by the availability of electron donors and acceptors to these microorganisms and the ability of sulfur-oxidizing denitrifiers to gain energy through concomitant S and H2 oxidation. We demonstrate that SLiMEs support taxonomically and metabolically diverse microorganisms, which, through developing syntrophic partnerships, overcome thermodynamic barriers imposed by the environmental conditions in the deep subsurface. PMID:27872277

The evolution of health status and chronic conditions in Catalonia, 1994-2006: the paradox of health revisited using the Blinder - Oaxaca decomposition.

PubMed

García-Altés, Anna; Pinilla, Jaime; Ortún, Vicente

2011-05-23

The paradox of health refers to the improvement in objective measures of health and the increase in the reported prevalence of chronic conditions. The objective of this paper is to test the paradox of health in Catalonia from 1994 to 2006. Longitudinal cross-sectional study using the Catalonia Health Interview Survey of 1994 and 2006. The approach used was the three-fold Blinder - Oaxaca decomposition, separating the part of the differential in mean visual analogue scale value (VAS) due to group differences in the predictors (prevalence effect), due to differences in the coefficients (severity effect), and an interaction term. Variables included were the VAS value, education level, labour status, marital status, all common chronic conditions over the two cross-sections, and a variable for non-common chronic conditions and other conditions. Sample weights have been applied. Results show that there is an increase in mean VAS for men aged 15-44, and a decrease in mean VAS for women aged 65-74 and 75 and more. The increase in mean VAS for men aged 15-44 could be explained by a decrease in the severity effect, which offsets the increase in the prevalence effect. The decrease in mean VAS for women aged 65-74 and 75 and more could be explained by an increase in the prevalence effect, which does not offset the decrease in the severity effect. The results of the present analysis corroborate the paradox of health hypothesis for the population of Catalonia, and highlight the need to be careful when measuring population health over time, as well as their usefulness to detect population's perceptions.

The evolution of health status and chronic conditions in Catalonia, 1994-2006: the paradox of health revisited using the Blinder - Oaxaca decomposition

PubMed Central

2011-01-01

Background The paradox of health refers to the improvement in objective measures of health and the increase in the reported prevalence of chronic conditions. The objective of this paper is to test the paradox of health in Catalonia from 1994 to 2006. Methods Longitudinal cross-sectional study using the Catalonia Health Interview Survey of 1994 and 2006. The approach used was the three-fold Blinder - Oaxaca decomposition, separating the part of the differential in mean visual analogue scale value (VAS) due to group differences in the predictors (prevalence effect), due to differences in the coefficients (severity effect), and an interaction term. Variables included were the VAS value, education level, labour status, marital status, all common chronic conditions over the two cross-sections, and a variable for non-common chronic conditions and other conditions. Sample weights have been applied. Results Results show that there is an increase in mean VAS for men aged 15-44, and a decrease in mean VAS for women aged 65-74 and 75 and more. The increase in mean VAS for men aged 15-44 could be explained by a decrease in the severity effect, which offsets the increase in the prevalence effect. The decrease in mean VAS for women aged 65-74 and 75 and more could be explained by an increase in the prevalence effect, which does not offset the decrease in the severity effect. Conclusions The results of the present analysis corroborate the paradox of health hypothesis for the population of Catalonia, and highlight the need to be careful when measuring population health over time, as well as their usefulness to detect population's perceptions. PMID:21605384

Do-or-die life cycles and diverse post-infection resistance mechanisms limit the evolution of parasite host ranges.

PubMed

Sieber, Michael; Gudelj, Ivana

2014-04-01

In light of the dynamic nature of parasite host ranges and documented potential for rapid host shifts, the observed high host specificity of most parasites remains an ecological paradox. Different variants of host-use trade-offs have become a mainstay of theoretical explanations of the prevalence of host specialism, but empirical evidence for such trade-offs is rare. We propose an alternative theory based on basic features of the parasite life cycle: host selection and subsequent intrahost replication. We introduce a new concept of effective burst size that accounts for the fact that successful host selection does not guarantee intrahost replication. Our theory makes a general prediction that a parasite will expand its host range if its effective burst size is positive. An in silico model of bacteria-phage coevolution verifies our predictions and demonstrates that the tendency for relatively narrow host ranges in parasites can be explained even in the absence of trade-offs. © 2014 John Wiley & Sons Ltd/CNRS.

Mysteries of TGF-β Paradox in Benign and Malignant Cells.

PubMed

Zhang, Qiang; Yu, Nengwang; Lee, Chung

2014-01-01

TGF-β regulates a wide range of biological functions including embryonic development, wound healing, organogenesis, immune modulation, and cancer progression. Interestingly, TGF-β is known to inhibit cell growth in benign cells but promote progression in cancer cells; this phenomenon is known as TGF-β paradox. To date, the mechanism of this paradox still remains a scientific mystery. In this review, we present our experience, along with the literature, in an attempt to answer this mystery. First, we observed that, on TGF-β engagement, there is a differential activation of Erk between benign and cancer cells. Since activated Erk is a major mediator in tumor progression and metastasis, a differentially activated Erk represents the answer to this mystery. Second, we identified a key player, PP2A-B56α, which is differentially recruited by the activated type I TGF-β receptor (TBRI) in benign and tumor cells, resulting in differential Erk activation. Finally, TGF-β stimulation leads to suppressed TBRs in tumor cells but not in benign cells. This differentially suppressed TBRs triggers differential recruitment of PP2A-B56α and, thus, differential activation of Erk. The above three events explain the mysteries of TGF-β paradox. Understanding the mechanism of TGF-β paradox will help us to predict indolent from aggressive cancers and develop novel anti-cancer strategies.

Mysteries of TGF-β Paradox in Benign and Malignant Cells

PubMed Central

Zhang, Qiang; Yu, Nengwang; Lee, Chung

2014-01-01

TGF-β regulates a wide range of biological functions including embryonic development, wound healing, organogenesis, immune modulation, and cancer progression. Interestingly, TGF-β is known to inhibit cell growth in benign cells but promote progression in cancer cells; this phenomenon is known as TGF-β paradox. To date, the mechanism of this paradox still remains a scientific mystery. In this review, we present our experience, along with the literature, in an attempt to answer this mystery. First, we observed that, on TGF-β engagement, there is a differential activation of Erk between benign and cancer cells. Since activated Erk is a major mediator in tumor progression and metastasis, a differentially activated Erk represents the answer to this mystery. Second, we identified a key player, PP2A-B56α, which is differentially recruited by the activated type I TGF-β receptor (TBRI) in benign and tumor cells, resulting in differential Erk activation. Finally, TGF-β stimulation leads to suppressed TBRs in tumor cells but not in benign cells. This differentially suppressed TBRs triggers differential recruitment of PP2A-B56α and, thus, differential activation of Erk. The above three events explain the mysteries of TGF-β paradox. Understanding the mechanism of TGF-β paradox will help us to predict indolent from aggressive cancers and develop novel anti-cancer strategies. PMID:24860782

Extreme diversity in noncalcifying haptophytes explains a major pigment paradox in open oceans

PubMed Central

Liu, Hui; Probert, Ian; Uitz, Julia; Claustre, Hervé; Aris-Brosou, Stéphane; Frada, Miguel; Not, Fabrice; de Vargas, Colomban

2009-01-01

The current paradigm holds that cyanobacteria, which evolved oxygenic photosynthesis more than 2 billion years ago, are still the major light harvesters driving primary productivity in open oceans. Here we show that tiny unicellular eukaryotes belonging to the photosynthetic lineage of the Haptophyta are dramatically diverse and ecologically dominant in the planktonic photic realm. The use of Haptophyta-specific primers and PCR conditions adapted for GC-rich genomes circumvented biases inherent in classical genetic approaches to exploring environmental eukaryotic biodiversity and led to the discovery of hundreds of unique haptophyte taxa in 5 clone libraries from subpolar and subtropical oceanic waters. Phylogenetic analyses suggest that this diversity emerged in Paleozoic oceans, thrived and diversified in the permanently oxygenated Mesozoic Panthalassa, and currently comprises thousands of ribotypic species, belonging primarily to low-abundance and ancient lineages of the “rare biosphere.” This extreme biodiversity coincides with the pervasive presence in the photic zone of the world ocean of 19′-hexanoyloxyfucoxanthin (19-Hex), an accessory photosynthetic pigment found exclusively in chloroplasts of haptophyte origin. Our new estimates of depth-integrated relative abundance of 19-Hex indicate that haptophytes dominate the chlorophyll a-normalized phytoplankton standing stock in modern oceans. Their ecologic and evolutionary success, arguably based on mixotrophy, may have significantly impacted the oceanic carbon pump. These results add to the growing evidence that the evolution of complex microbial eukaryotic cells is a critical force in the functioning of the biosphere. PMID:19622724

Extreme diversity in noncalcifying haptophytes explains a major pigment paradox in open oceans.

PubMed

Liu, Hui; Probert, Ian; Uitz, Julia; Claustre, Hervé; Aris-Brosou, Stéphane; Frada, Miguel; Not, Fabrice; de Vargas, Colomban

2009-08-04

The current paradigm holds that cyanobacteria, which evolved oxygenic photosynthesis more than 2 billion years ago, are still the major light harvesters driving primary productivity in open oceans. Here we show that tiny unicellular eukaryotes belonging to the photosynthetic lineage of the Haptophyta are dramatically diverse and ecologically dominant in the planktonic photic realm. The use of Haptophyta-specific primers and PCR conditions adapted for GC-rich genomes circumvented biases inherent in classical genetic approaches to exploring environmental eukaryotic biodiversity and led to the discovery of hundreds of unique haptophyte taxa in 5 clone libraries from subpolar and subtropical oceanic waters. Phylogenetic analyses suggest that this diversity emerged in Paleozoic oceans, thrived and diversified in the permanently oxygenated Mesozoic Panthalassa, and currently comprises thousands of ribotypic species, belonging primarily to low-abundance and ancient lineages of the "rare biosphere." This extreme biodiversity coincides with the pervasive presence in the photic zone of the world ocean of 19'-hexanoyloxyfucoxanthin (19-Hex), an accessory photosynthetic pigment found exclusively in chloroplasts of haptophyte origin. Our new estimates of depth-integrated relative abundance of 19-Hex indicate that haptophytes dominate the chlorophyll a-normalized phytoplankton standing stock in modern oceans. Their ecologic and evolutionary success, arguably based on mixotrophy, may have significantly impacted the oceanic carbon pump. These results add to the growing evidence that the evolution of complex microbial eukaryotic cells is a critical force in the functioning of the biosphere.

Interrogating the Grammars of Institutions and Injustice

ERIC Educational Resources Information Center

Bradley, Deborah

2017-01-01

This editorial introduction to "Action, Criticism, and Theory for Music Education" "ACT" 16 (3) explores institutions as sites of paradox whose mission statements (or constitutions in the case of government) suggest concerns for diversity and inclusion but whose "grammars" (Bonilla-Silva 2011) frame thought and action…

SES Gradients Among Mexicans in the United States and in Mexico: A New Twist to the Hispanic Paradox?

PubMed Central

Palloni, Alberto; Riosmena, Fernando; Wong, Rebeca

2016-01-01

Recent empirical findings have suggested the existence of a twist in the Hispanic paradox, in which Mexican and other Hispanic foreign-born migrants living in the United States experience shallower socioeconomic status (SES) health disparities than those in the U.S. population. In this article, we seek to replicate this finding and test conjectures that could explain this new observed phenomenon using objective indicators of adult health by educational attainment in several groups: (1) Mexicanborn individuals living in Mexico and in the United States, (2) U.S.-born Mexican Americans, and (3) non-Hispanic American whites. Our analytical strategy improves upon previous research on three fronts. First, we derive four hypotheses from a general framework that has also been used to explain the standard Hispanic paradox. Second, we study biomarkers rather than self-reported health and related conditions. Third, we use a binational data platform that includes both Mexicans living in Mexico (Mexican National Health and Nutrition Survey 2006) and Mexican migrants to the United States (NHANES 1999–2010). We find steep education gradients among Mexicans living in Mexico’s urban areas in five of six biomarkers of metabolic syndrome (MetS) and in the overall MetS score. Mexican migrants living in the United States experience similar patterns to Mexicans living in Mexico in glucose and obesity biomarkers. These results are inconsistent with previous findings, suggesting that Mexican migrants in the United States experience significantly attenuated health gradients relative to the non-Hispanic white U.S. population. Our empirical evidence also contradicts the idea that SES-health gradients in Mexico are shallower than those in the United States and could be invoked to explain shallower gradients among Mexicans living in the United States. PMID:27655408

Astrobiological Phase Transition: Towards Resolution of Fermi's Paradox

NASA Astrophysics Data System (ADS)

Ćirković, Milan M.; Vukotić, Branislav

2008-12-01

Can astrophysics explain Fermi’s paradox or the “Great Silence” problem? If available, such explanation would be advantageous over most of those suggested in literature which rely on unverifiable cultural and/or sociological assumptions. We suggest, instead, a general astrobiological paradigm which might offer a physical and empirically testable paradox resolution. Based on the idea of James Annis, we develop a model of an astrobiological phase transition of the Milky Way, based on the concept of the global regulation mechanism(s). The dominant regulation mechanisms, arguably, are γ-ray bursts, whose properties and cosmological evolution are becoming well-understood. Secular evolution of regulation mechanisms leads to the brief epoch of phase transition: from an essentially dead place, with pockets of low-complexity life restricted to planetary surfaces, it will, on a short (Fermi-Hart) timescale, become filled with high-complexity life. An observation selection effect explains why we are not, in spite of the very small prior probability, to be surprised at being located in that brief phase of disequilibrium. In addition, we show that, although the phase-transition model may explain the “Great Silence”, it is not supportive of the “contact pessimist” position. To the contrary, the phase-transition model offers a rational motivation for continuation and extension of our present-day Search for ExtraTerrestrial Intelligence (SETI) endeavours. Some of the unequivocal and testable predictions of our model include the decrease of extinction risk in the history of terrestrial life, the absence of any traces of Galactic societies significantly older than human society, complete lack of any extragalactic intelligent signals or phenomena, and the presence of ubiquitous low-complexity life in the Milky Way.

SES Gradients Among Mexicans in the United States and in Mexico: A New Twist to the Hispanic Paradox?

PubMed

Beltrán-Sánchez, Hiram; Palloni, Alberto; Riosmena, Fernando; Wong, Rebeca

2016-10-01

Recent empirical findings have suggested the existence of a twist in the Hispanic paradox, in which Mexican and other Hispanic foreign-born migrants living in the United States experience shallower socioeconomic status (SES) health disparities than those in the U.S. In this article, we seek to replicate this finding and test conjectures that could explain this new observed phenomenon using objective indicators of adult health by educational attainment in several groups: (1) Mexican-born individuals living in Mexico and in the United States, (2) U.S.-born Mexican Americans, and (3) non-Hispanic American whites. Our analytical strategy improves upon previous research on three fronts. First, we derive four hypotheses from a general framework that has also been used to explain the standard Hispanic paradox. Second, we study biomarkers rather than self-reported health and related conditions. Third, we use a binational data platform that includes both Mexicans living in Mexico (Mexican National Health and Nutrition Survey 2006) and Mexican migrants to the United States (NHANES 1999-2010). We find steep education gradients among Mexicans living in Mexico's urban areas in five of six biomarkers of metabolic syndrome (MetS) and in the overall MetS score. Mexican migrants living in the United States experience similar patterns to Mexicans living in Mexico in glucose and obesity biomarkers. These results are inconsistent with previous findings, suggesting that Mexican migrants in the United States experience significantly attenuated health gradients relative to the non-Hispanic white U.S. Our empirical evidence also contradicts the idea that SES-health gradients in Mexico are shallower than those in the United States and could be invoked to explain shallower gradients among Mexicans living in the United States.

Astrobiological phase transition: towards resolution of Fermi's paradox.

PubMed

Cirković, Milan M; Vukotić, Branislav

2008-12-01

Can astrophysics explain Fermi's paradox or the "Great Silence" problem? If available, such explanation would be advantageous over most of those suggested in literature which rely on unverifiable cultural and/or sociological assumptions. We suggest, instead, a general astrobiological paradigm which might offer a physical and empirically testable paradox resolution. Based on the idea of James Annis, we develop a model of an astrobiological phase transition of the Milky Way, based on the concept of the global regulation mechanism(s). The dominant regulation mechanisms, arguably, are gamma-ray bursts, whose properties and cosmological evolution are becoming well-understood. Secular evolution of regulation mechanisms leads to the brief epoch of phase transition: from an essentially dead place, with pockets of low-complexity life restricted to planetary surfaces, it will, on a short (Fermi-Hart) timescale, become filled with high-complexity life. An observation selection effect explains why we are not, in spite of the very small prior probability, to be surprised at being located in that brief phase of disequilibrium. In addition, we show that, although the phase-transition model may explain the "Great Silence", it is not supportive of the "contact pessimist" position. To the contrary, the phase-transition model offers a rational motivation for continuation and extension of our present-day Search for ExtraTerrestrial Intelligence (SETI) endeavours. Some of the unequivocal and testable predictions of our model include the decrease of extinction risk in the history of terrestrial life, the absence of any traces of Galactic societies significantly older than human society, complete lack of any extragalactic intelligent signals or phenomena, and the presence of ubiquitous low-complexity life in the Milky Way.

Explaining the 'immigration advantage' and the 'biculturalism paradox': an application of the theory of demoralization.

PubMed

de Figueiredo, John M

2014-03-01

Recent immigrants have better mental health than the natives ('immigration advantage'). Biculturals have better mental health than the monoculturals ('biculturalism paradox'). Mexican immigrants have lower rates of psychopathology than the U.S. population. This is less true for Cubans and not true for Puerto Ricans. The 'advantage' also occurs in other groups. Biculturals have better mental health and endorse both cultures. The theory of demoralization predicts that borrowing values from both cultures and applying them judiciously are more conducive to mental health than indiscriminately subscribing to either culture. The findings are consistent with the theory of demoralization.

Sheldon spectrum and the plankton paradox: two sides of the same coin-a trait-based plankton size-spectrum model.

PubMed

Cuesta, José A; Delius, Gustav W; Law, Richard

2018-01-01

The Sheldon spectrum describes a remarkable regularity in aquatic ecosystems: the biomass density as a function of logarithmic body mass is approximately constant over many orders of magnitude. While size-spectrum models have explained this phenomenon for assemblages of multicellular organisms, this paper introduces a species-resolved size-spectrum model to explain the phenomenon in unicellular plankton. A Sheldon spectrum spanning the cell-size range of unicellular plankton necessarily consists of a large number of coexisting species covering a wide range of characteristic sizes. The coexistence of many phytoplankton species feeding on a small number of resources is known as the Paradox of the Plankton. Our model resolves the paradox by showing that coexistence is facilitated by the allometric scaling of four physiological rates. Two of the allometries have empirical support, the remaining two emerge from predator-prey interactions exactly when the abundances follow a Sheldon spectrum. Our plankton model is a scale-invariant trait-based size-spectrum model: it describes the abundance of phyto- and zooplankton cells as a function of both size and species trait (the maximal size before cell division). It incorporates growth due to resource consumption and predation on smaller cells, death due to predation, and a flexible cell division process. We give analytic solutions at steady state for both the within-species size distributions and the relative abundances across species.

Marine methane paradox explained by bacterial degradation of dissolved organic matter

NASA Astrophysics Data System (ADS)

Repeta, Daniel J.; Ferrón, Sara; Sosa, Oscar A.; Johnson, Carl G.; Repeta, Lucas D.; Acker, Marianne; Delong, Edward F.; Karl, David M.

2016-12-01

Biogenic methane is widely thought to be a product of archaeal methanogenesis, an anaerobic process that is inhibited or outcompeted by the presence of oxygen and sulfate. Yet a large fraction of marine methane delivered to the atmosphere is produced in high-sulfate, fully oxygenated surface waters that have methane concentrations above atmospheric equilibrium values, an unexplained phenomenon referred to as the marine methane paradox. Here we use nuclear magnetic resonance spectroscopy to show that polysaccharide esters of three phosphonic acids are important constituents of dissolved organic matter in seawater from the North Pacific. In seawater and pure culture incubations, bacterial degradation of these dissolved organic matter phosphonates in the presence of oxygen releases methane, ethylene and propylene gas. Moreover, we found that in mutants of a methane-producing marine bacterium, Pseudomonas stutzeri, disrupted in the C-P lyase phosphonate degradation pathway, methanogenesis was also disabled, indicating that the C-P lyase pathway can catalyse methane production from marine dissolved organic matter. Finally, the carbon stable isotope ratio of methane emitted during our incubations agrees well with anomalous isotopic characteristics of seawater methane. We estimate that daily cycling of only about 0.25% of the organic matter phosphonate inventory would support the entire atmospheric methane flux at our study site. We conclude that aerobic bacterial degradation of phosphonate esters in dissolved organic matter may explain the marine methane paradox.

The paradox of vertical σ2 in foreland fold and thrust belts

NASA Astrophysics Data System (ADS)

Tavani, Stefano

2014-05-01

Occurrence of aesthetically appealing thrust systems and associated large scale anticlines, in both active and fossil foreland fold and thrust belts, is commonly interpreted as an evidence for Andersonian compressional framework. Indeed, these structures would testify for a roughly vertical σ3. Such a correlation between thrusts occurrence and stress field orientation, however, frequently fails to explain denser observations at a smaller scale. The syn-orogenic deformation meso-structures hosted in exposed km-scale thrust-related folds, in fact, frequently and paradoxically witness for a syn-thrusting strike-slip stress configuration, with a near-vertical σ2 and a sub-horizontal σ3. This apparent widespread inconsistency between syn-orogenic meso-structures and stress field orientation is here named "the σ2 paradox". A possible explanation for such a paradox is provided by inherited extensional deformation structures commonly developed prior to thrusting, in the flexural foreland basins located ahead of fold and thrust belts. Thrust nucleation and propagation is facilitated and driven by the positive inversion of the extensional inheritances, and their subsequent linkage. This process eventually leads to the development of large reverse fault zones and can occur both in compressive and strike-slip stress configurations.

The ecology of eating: smaller portion sizes in France Than in the United States help explain the French paradox.

PubMed

Rozin, Paul; Kabnick, Kimberly; Pete, Erin; Fischler, Claude; Shields, Christy

2003-09-01

Part of the "French paradox" can be explained by the fact that the French eat less than Americans. We document that French portion sizes are smaller in comparable restaurants, in the sizes of individual portions of foods (but not other items) in supermarkets, in portions specified in cookbooks, and in the prominence of "all you can eat" restaurants in dining guides. We also present data, from observations at McDonald's, that the French take longer to eat than Americans. Our results suggest that in the domain of eating, and more generally, more attention should be paid to ecological factors, even though their mechanism of operation is transparent, and hence less revealing of fundamental psychological processes. Ironically, although the French eat less than Americans, they seem to eat for a longer period of time, and hence have more food experience. The French can have their cake and eat it as well.

Gender disparities in health and healthcare: results from the Portuguese National Health Interview Survey.

PubMed

Perelman, Julian; Fernandes, Ana; Mateus, Céu

2012-12-01

Although women experience poorer health conditions during their lives, they live longer than men. The main explanations for this paradox suggest that women's excess of ill-health is limited to minor illnesses and their different attitudes toward health. The authors test these assumptions by investigating disparities between men and women in health and healthcare in Portugal. Data are used from the Portuguese National Health Interview Survey 2005/2006 (N = 33,662). Multivariate regressions showed that women were more likely to report worse self-rated health, more days with disability, higher prevalence of hypertension, chronic pain, cancer, anxiety and depression, and more medical consultations. Heart disease was significantly more prevalent among men, possibly explaining part of the paradox. Women's more frequent use of medical consultations may reflect their heightened awareness of health problems, which may protect them against early death. Gender differences in socioeconomic status explain part of the differences in health, but fail to provide a complete understanding.

Accounting for Local Dependence with the Rasch Model: The Paradox of Information Increase.

PubMed

Andrich, David

Test theories imply statistical, local independence. Where local independence is violated, models of modern test theory that account for it have been proposed. One violation of local independence occurs when the response to one item governs the response to a subsequent item. Expanding on a formulation of this kind of violation between two items in the dichotomous Rasch model, this paper derives three related implications. First, it formalises how the polytomous Rasch model for an item constituted by summing the scores of the dependent items absorbs the dependence in its threshold structure. Second, it shows that as a consequence the unit when the dependence is accounted for is not the same as if the items had no response dependence. Third, it explains the paradox, known, but not explained in the literature, that the greater the dependence of the constituent items the greater the apparent information in the constituted polytomous item when it should provide less information.

Defend or repair? Explaining responses to in-group moral failure by disentangling feelings of shame, rejection, and inferiority.

PubMed

Gausel, Nicolay; Leach, Colin Wayne; Vignoles, Vivian L; Brown, Rupert

2012-05-01

Research on shame about in-group moral failure has yielded paradoxical results. In some studies, shame predicts self-defensive motivations to withdraw. In other studies, shame predicts pro-social motivations, such as restitution. We think that this paradox can be explained by disentangling the numerous appraisals and feelings subsumed under the label "shame." In 2 studies, we asked community samples of Norwegians about their in-group's discrimination against the Tater minority. Confirmatory factor analysis validated the measures of the appraisals and feelings used in Study 1 (N = 206) and Study 2 (N = 173). In both studies, an appraisal of the in-group as suffering a moral defect best predicted felt shame, whereas an appraisal of concern for condemnation of the in-group best predicted felt rejection. In both studies, felt rejection best predicted self-defensive motivation, whereas felt shame best predicted pro-social motivation. Implications for conceptualizing and studying shame are discussed.

A vulnerability paradox in the cross-national prevalence of post-traumatic stress disorder.

PubMed

Dückers, Michel L A; Alisic, Eva; Brewin, Chris R

2016-10-01

Determinants of cross-national differences in the prevalence of mental illness are poorly understood. To test whether national post-traumatic stress disorder (PTSD) rates can be explained by (a) rates of exposure to trauma and (b) countries' overall cultural and socioeconomic vulnerability to adversity. We collected general population studies on lifetime PTSD and trauma exposure, measured using the WHO Composite International Diagnostic Interview (DSM-IV). PTSD prevalence was identified for 24 countries (86 687 respondents) and exposure for 16 countries (53 038 respondents). PTSD was predicted using exposure and vulnerability data. PTSD is related positively to exposure but negatively to country vulnerability. Together, exposure, vulnerability and their interaction explain approximately 75% of variance in the national prevalence of PTSD. Contrary to expectations based on individual risk factors, we identified a paradox whereby greater country vulnerability is associated with a decreased, rather than increased, risk of PTSD for its citizens. © The Royal College of Psychiatrists 2016.

Diversity and Its Discontents: Cultural Conflict and Common Ground in Contemporary American Society.

ERIC Educational Resources Information Center

Smelser, Neil J., Ed.; Alexander, Jeffrey C., Ed.

Sociologists, political theorists, and social historians explore ideological differences, theoretical disputes, social processes, and institutional change related to cultural conflict and social solidarity in the United States. The essays are: (1) "Introduction: The Ideological Discourses of Cultural Discontent. Paradoxes, Realities, and…

On Stochastic Dependence

ERIC Educational Resources Information Center

Meyer, Joerg M.

2018-01-01

The contrary of stochastic independence splits up into two cases: pairs of events being favourable or being unfavourable. Examples show that both notions have quite unexpected properties, some of them being opposite to intuition. For example, transitivity does not hold. Stochastic dependence is also useful to explain cases of Simpson's paradox.

Relative Deprivation and the Gender Wage Gap.

ERIC Educational Resources Information Center

Jackson, Linda A.

1989-01-01

Discusses how gender differences in the value of pay, based on relative deprivation theory, explain women's paradoxical contentment with lower wages. Presents a model of pay satisfaction to integrate value-based and comparative-referent explanations of the relationship between gender and pay satisfaction. Discusses economic approaches to the…

The Giffen Effect: A Note on Economic Purposes.

ERIC Educational Resources Information Center

Williams, William D.

1990-01-01

Describes the Giffen effect: demand for a commodity increases as price increases. Explains how applying control theory eliminates the paradox that the Giffen effect presents to classic economics supply and demand theory. Notes the differences in how conventional demand theory and control theory treat consumer behavior. (CH)

Neoliberal Paradoxes of Language Learning: Xenophobia and International Communication

ERIC Educational Resources Information Center

Kubota, Ryuko

2016-01-01

Neoliberal ideology compels people to develop language skills as human capital. As English is considered to be the most useful language for global communication, learning, and teaching, English has been promoted in many countries. However, the belief that English connects people from diverse linguistic backgrounds in a borderless society…

The paradox of forest fragmentation genetics

Treesearch

Andrea T. Kramer; Jennifer L. Ison; Mary V. Ashley; Henry F. Howe

2008-01-01

Theory predicts widespread loss of genetic diversity from drift and inbreeding in trees subjected to habitat fragmentation, yet empirical support of this theory is scarce. We argue that population genetics theory may be misapplied in light of ecological realities that, when recognized, require scrutiny of underlying evolutionary assumptions. One ecological reality is...

The Value Paradox--Inducting Undergraduate University Students in a Time of Austerity

ERIC Educational Resources Information Center

Jones, Tim; Upton, Penney; Wilkinson, Dean J.

2013-01-01

The challenges facing UK higher education are both well documented and controversial; however, pitted against this context is the requirement for psychology departments to provide an increasingly rich and diverse university experience for students, whilst ensuring progression and retention remain central to undergraduate provision. Despite the…

Social Capital and Human Mortality: Explaining the Rural Paradox with County-Level Mortality Data

PubMed Central

Jensen, Leif; Haran, Murali

2014-01-01

The “rural paradox” refers to standardized mortality rates in rural areas that are unexpectedly low in view of well-known economic and infrastructural disadvantages there. We explore this paradox by incorporating social capital, a promising explanatory factor that has seldom been incorporated into residential mortality research. We do so while being attentive to spatial dependence, a statistical problem often ignored in mortality research. Analyzing data for counties in the contiguous United States, we find that: (1) the rural paradox is confirmed with both metro/non-metro and rural-urban continuum codes, (2) social capital significantly reduces the impacts of residence on mortality after controlling for race/ethnicity and socioeconomic covariates, (3) this attenuation is greater when a spatial perspective is imposed on the analysis, (4) social capital is negatively associated with mortality at the county level, and (5) spatial dependence is strongly in evidence. A spatial approach is necessary in county-level analyses such as ours to yield unbiased estimates and optimal model fit. PMID:25392565

Differentially expressed microRNAs in lung adenocarcinoma invert effects of copy number aberrations of prognostic genes

PubMed Central

Tokar, Tomas; Pastrello, Chiara; Ramnarine, Varune R.; Zhu, Chang-Qi; Craddock, Kenneth J.; Pikor, Larrisa A.; Vucic, Emily A.; Vary, Simon; Shepherd, Frances A.; Tsao, Ming-Sound; Lam, Wan L.; Jurisica, Igor

2018-01-01

In many cancers, significantly down- or upregulated genes are found within chromosomal regions with DNA copy number alteration opposite to the expression changes. Generally, this paradox has been overlooked as noise, but can potentially be a consequence of interference of epigenetic regulatory mechanisms, including microRNA-mediated control of mRNA levels. To explore potential associations between microRNAs and paradoxes in non-small-cell lung cancer (NSCLC) we curated and analyzed lung adenocarcinoma (LUAD) data, comprising gene expressions, copy number aberrations (CNAs) and microRNA expressions. We integrated data from 1,062 tumor samples and 241 normal lung samples, including newly-generated array comparative genomic hybridization (aCGH) data from 63 LUAD samples. We identified 85 “paradoxical” genes whose differential expression consistently contrasted with aberrations of their copy numbers. Paradoxical status of 70 out of 85 genes was validated on sample-wise basis using The Cancer Genome Atlas (TCGA) LUAD data. Of these, 41 genes are prognostic and form a clinically relevant signature, which we validated on three independent datasets. By meta-analysis of results from 9 LUAD microRNA expression studies we identified 24 consistently-deregulated microRNAs. Using TCGA-LUAD data we showed that deregulation of 19 of these microRNAs explains differential expression of the paradoxical genes. Our results show that deregulation of paradoxical genes is crucial in LUAD and their expression pattern is maintained epigenetically, defying gene copy number status. PMID:29507679

Molecular Pathological Epidemiology Gives Clues to Paradoxical Findings

PubMed Central

Nishihara, Reiko; VanderWeele, Tyler J.; Shibuya, Kenji; Mittleman, Murray A.; Wang, Molin; Field, Alison E.; Giovannucci, Edward; Lochhead, Paul; Ogino, Shuji

2015-01-01

A number of epidemiologic studies have described what appear to be paradoxical associations, where an incongruous relationship is observed between a certain well-established risk factor for disease incidence and favorable clinical outcome among patients with that disease. For example, the “obesity paradox” represents the association between obesity and better survival among patients with a certain disease such as coronary heart disease. Paradoxical observations cause vexing clinical and public health problems as they raise questions on causal relationships and hinder the development of effective interventions. Compelling evidence indicates that pathogenic processes encompass molecular alterations within cells and the microenvironment, influenced by various exogenous and endogenous exposures, and that interpersonal heterogeneity in molecular pathology and pathophysiology exists among patients with any given disease. In this article, we introduce methods of the emerging integrative interdisciplinary field of molecular pathological epidemiology (MPE), which is founded on the unique disease principle and disease continuum theory. We analyze and decipher apparent paradoxical findings, utilizing the MPE approach and available literature data on tumor somatic genetic and epigenetic characteristics. Through our analyses in colorectal cancer, renal cell carcinoma, and glioblastoma (malignant brain tumor), we can readily explain paradoxical associations between disease risk factors and better prognosis among disease patients. The MPE paradigm and approach can be applied to not only neoplasms but also various non-neoplastic diseases where there exists indisputable ubiquitous heterogeneity of pathogenesis and molecular pathology. The MPE paradigm including consideration of disease heterogeneity plays an essential role in advancements of precision medicine and public health. PMID:26445996

The immunomodulatory effects of interferon-gamma on mature B-lymphocyte responses.

PubMed

Jurado, A; Carballido, J; Griffel, H; Hochkeppel, H K; Wetzel, G D

1989-06-15

Interferon-gamma (IFN-gamma) exerts a broad spectrum of activities which affect the responses of mature B-cells. It strongly inhibits B-cell activation, acts as a B-cell growth factor (BCGF), and also induces final differentiation to immunoglobulin (Ig) production. IFN-gamma is deeply involved in the differential control of isotype expression, as it enhances IgG2a production and suppresses both IgG1 and IgE production. Although it is now possible to draw a general scheme of the effects of IFN-gamma on B-cells, a number of paradoxical results still exist in the field. In this manuscript, different experimental systems are analyzed in an attempt to explain these apparent paradoxes.

Detection of verbal discordances during sleep.

PubMed

Perrin, Fabien; Bastuji, Hélène; Garcia-Larrea, Luis

2002-07-19

We used an electrophysiological marker of linguistic discordance, the N400 wave, to investigate how linguistic and pseudo-linguistic stimuli are categorised during sleep as compared to waking. During wakefulness, signs of discordance detection were, as expected, greater for pseudo-words than for real but semantically incongruous words, relative to congruous words. In sleep stage 2 all signs of hierarchic process of discordance disappeared. A new hierarchic process reappeared in paradoxical sleep, which differed from that of waking, responses to pseudo-words being similar to those to congruous words. Linguistic absurdity appears to be accepted in a different manner during paradoxical sleep than during waking, and this might explain why absurd contents are so naturally incorporated into otherwise plausible dream stories.

Repetition Blindness: An Emergent Property of Inter-Item Competition

ERIC Educational Resources Information Center

Morris, Alison L.; Still, Mary L.; Caldwell-Harris, Catherine L.

2009-01-01

Repeating an item in a brief or rapid display usually produces faster or more accurate identification of the item (repetition priming), but sometimes produces the opposite effect (repetition blindness). We present a theory of short-term repetition effects, the "competition hypothesis," which explains these paradoxical outcomes. The central tenet…

Paradoxical Inequalities: Adolescent Peer Relations in Indian Secondary Schools

ERIC Educational Resources Information Center

Milner, Murray, Jr.

2013-01-01

Peer relationships in secondary schools in two different cultural areas of India are compared. A general theory of status relations and a specification of the distinctive cultural features of each area are used to explain the observed differences in peer inequality, clique formation, petty deviance, putdowns, fashion consciousness, romantic…

Resistance Management Techniques of Milton H. Erickson, M.D.: An Application to Nonhypnotic Mental Health Counseling.

ERIC Educational Resources Information Center

Otani, Akira

1989-01-01

Delineates five selected hypnotically based techniques of client resistance management pioneered by Milton H. Erickson: acceptance; paradoxical encouragement; reframing; displacement; dissociation. Explains how techniques can be applied to nonhypnotic mental health counseling. Discusses relevant clinical, theoretical, and empirical issues related…

Is vaccenic acid (18:1t n-7) associated with an increased incidence of hip fracture? An explanation for the calcium paradox.

PubMed

Hamazaki, Kei; Suzuki, Nobuo; Kitamura, Kei-Ichiro; Hattori, Atsuhiko; Nagasawa, Tetsuro; Itomura, Miho; Hamazaki, Tomohito

2016-06-01

High calcium intake may increase hip fracture (HF) incidence. This phenomenon, known as the calcium paradox, might be explained by vaccenic acid (18:1t n-7, VA), the highly specific trans fatty acid (TFA) present in dairy products. First, we ecologically investigated the relationship between 18:1 TFA intake and HF incidence using data from 12 to 13 European countries collected before 2000; then we measured the effects of VA and elaidic acid (18:1t n-9, EA) on osteoblasts from goldfish scales (tissues very similar to mammalian bone), with alkaline phosphatase as a marker; and finally we measured the effect of VA on mRNA expression in the scales for the major bone proteins type I collagen and osteocalcin. HF incidence was significantly correlated with 18:1 TFA intake in men (r=0.57) and women (r=0.65). Incubation with 1μmol/L VA and EA for 48h significantly decreased alkaline phosphatase activity by 25% and 21%, respectively. Incubation of scales with 10μmol/L VA for 48h significantly decreased mRNA expression for type I collagen and osteocalcin (by about 50%). In conclusion, VA may be causatively related to HF and could explain the calcium paradox. It may be prudent to reduce 18:1 TFA intake, irrespective of trans positions, to prevent HF. Copyright © 2016 Elsevier Ltd. All rights reserved.

Paradoxical correlation between signal in functional magnetic resonance imaging and deoxygenated haemoglobin content in capillaries: a new theoretical explanation

NASA Astrophysics Data System (ADS)

Yamamoto, Toru; Kato, Toshinori

2002-04-01

Signal increases in functional magnetic resonance imaging (fMRI) are believed to be a result of decreased paramagnetic deoxygenated haemoglobin (deoxyHb) content in the neural activation area. However, discrepancies in this canonical blood oxygenation level dependent (BOLD) theory have been pointed out in studies using optical techniques, which directly measure haemoglobin changes. To explain the discrepancies, we developed a new theory bridging magnetic resonance (MR) signal and haemoglobin changes. We focused on capillary influences, which have been neglected in most previous fMRI studies and performed a combined fMRI and near-infrared spectroscopy (NIRS) study using a language task. Paradoxically, both the MR signal and deoxyHb content increased in Broca's area. On the other hand, fMRI activation in the auditory area near large veins correlated with a mirror-image decrease in deoxyHb and increase in oxygenated haemoglobin (oxyHb), in agreement with canonical BOLD theory. All fMRI signal changes correlated consistently with changes in oxyHb, the diamagnetism of which is insensitive to MR. We concluded that the discrepancy with the canonical BOLD theory is caused by the fact that the BOLD theory ignores the effect of the capillaries. Our theory explains the paradoxical phenomena of the oxyHb and deoxyHb contributions to the MR signal and gives a new insight into the precise haemodynamics of activation by analysing fMRI and NIRS data.

Solutions to Peto's paradox revealed by mathematical modelling and cross-species cancer gene analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caulin, Aleah F.; Graham, Trevor A.; Wang, Li-San

Whales have 1000-fold more cells than humans and mice have 1000-fold fewer; however, cancer risk across species does not increase with the number of somatic cells and the lifespan of the organism. This observation is known as Peto's paradox. How much would evolution have to change the parameters of somatic evolution in order to equalize the cancer risk between species that differ by orders of magnitude in size? Analysis of previously published models of colorectal cancer suggests that a two- to three-fold decrease in the mutation rate or stem cell division rate is enough to reduce a whale's cancer riskmore » to that of a human. Similarly, the addition of one to two required tumour-suppressor gene mutations would also be sufficient. Also, we surveyed mammalian genomes and did not find a positive correlation of tumour-suppressor genes with increasing body mass and longevity. However, we found evidence of the amplification of TP53 in elephants, MAL in horses and FBXO31 in microbats, which might explain Peto's paradox in those species. Lastly, exploring parameters that evolution may have fine-tuned in large, long-lived organisms will help guide future experiments to reveal the underlying biology responsible for Peto's paradox and guide cancer prevention in humans.« less

Solutions to Peto's paradox revealed by mathematical modelling and cross-species cancer gene analysis

DOE PAGES

Caulin, Aleah F.; Graham, Trevor A.; Wang, Li-San; ...

2015-06-08

Whales have 1000-fold more cells than humans and mice have 1000-fold fewer; however, cancer risk across species does not increase with the number of somatic cells and the lifespan of the organism. This observation is known as Peto's paradox. How much would evolution have to change the parameters of somatic evolution in order to equalize the cancer risk between species that differ by orders of magnitude in size? Analysis of previously published models of colorectal cancer suggests that a two- to three-fold decrease in the mutation rate or stem cell division rate is enough to reduce a whale's cancer riskmore » to that of a human. Similarly, the addition of one to two required tumour-suppressor gene mutations would also be sufficient. Also, we surveyed mammalian genomes and did not find a positive correlation of tumour-suppressor genes with increasing body mass and longevity. However, we found evidence of the amplification of TP53 in elephants, MAL in horses and FBXO31 in microbats, which might explain Peto's paradox in those species. Lastly, exploring parameters that evolution may have fine-tuned in large, long-lived organisms will help guide future experiments to reveal the underlying biology responsible for Peto's paradox and guide cancer prevention in humans.« less

Empirical corroboration of an earlier theoretical resolution to the UV paradox of insect polarized skylight orientation.

PubMed

Wang, Xin; Gao, Jun; Fan, Zhiguo

2014-02-01

It is surprising that many insect species use only the ultraviolet (UV) component of the polarized skylight for orientation and navigation purposes, while both the intensity and the degree of polarization of light from the clear sky are lower in the UV than at longer (blue, green, red) wavelengths. Why have these insects chosen the UV part of the polarized skylight? This strange phenomenon is called the "UV-sky-pol paradox". Although earlier several speculations tried to resolve this paradox, they did this without any quantitative data. A theoretical and computational model has convincingly explained why it is advantageous for certain animals to detect celestial polarization in the UV. We performed a sky-polarimetric approach and built a polarized skylight sensor that models the processing of polarization signals by insect photoreceptors. Using this model sensor, we carried out measurements under clear and cloudy sky conditions. Our results showed that light from the cloudy sky has maximal degree of polarization in the UV. Furthermore, under both clear and cloudy skies the angle of polarization of skylight can be detected with a higher accuracy. By this, we corroborated empirically the soundness of the earlier computational resolution of the UV-sky-pol paradox.

Empirical corroboration of an earlier theoretical resolution to the UV paradox of insect polarized skylight orientation

NASA Astrophysics Data System (ADS)

Wang, Xin; Gao, Jun; Fan, Zhiguo

2014-02-01

It is surprising that many insect species use only the ultraviolet (UV) component of the polarized skylight for orientation and navigation purposes, while both the intensity and the degree of polarization of light from the clear sky are lower in the UV than at longer (blue, green, red) wavelengths. Why have these insects chosen the UV part of the polarized skylight? This strange phenomenon is called the "UV-sky-pol paradox". Although earlier several speculations tried to resolve this paradox, they did this without any quantitative data. A theoretical and computational model has convincingly explained why it is advantageous for certain animals to detect celestial polarization in the UV. We performed a sky-polarimetric approach and built a polarized skylight sensor that models the processing of polarization signals by insect photoreceptors. Using this model sensor, we carried out measurements under clear and cloudy sky conditions. Our results showed that light from the cloudy sky has maximal degree of polarization in the UV. Furthermore, under both clear and cloudy skies the angle of polarization of skylight can be detected with a higher accuracy. By this, we corroborated empirically the soundness of the earlier computational resolution of the UV-sky-pol paradox.

Complex Systems, Interdisciplinary Collaboration, and Institutional Renewal

ERIC Educational Resources Information Center

Plank, Jeffrey; Feldon, David; Sherman, William; Elliot, Jennifer

2011-01-01

Research-intensive universities enjoy--or suffer--a paradoxical reputation: They are thought to be dedicated to both cutting-edge research and to the preservation of the canon. They are seen as broad and diverse communities of scholars with a vibrant collective intellectual life, yet also as silos of disciplinary entrenchment. Most significantly,…

The paradox of cognitive flexibility in autism

PubMed Central

Geurts, Hilde M.; Corbett, Blythe; Solomon, Marjorie

2017-01-01

We present an overview of current literature addressing cognitive flexibility in autism spectrum disorders. Based on recent studies at multiple sites, using diverse methods and participants of different autism subtypes, ages and cognitive levels, no consistent evidence for cognitive flexibility deficits was found. Researchers and clinicians assume that inflexible everyday behaviors in autism are directly related to cognitive flexibility deficits as assessed by clinical and experimental measures. However, there is a large gap between the day-to-day behavioral flexibility and that measured with these cognitive flexibility tasks. To advance the field, experimental measures must evolve to reflect mechanistic models of flexibility deficits. Moreover, ecologically valid measures are required to be able to resolve the paradox between cognitive and behavioral inflexibility. PMID:19138551

Food for Thought.

ERIC Educational Resources Information Center

Murfin, Brian

1998-01-01

The Inuit subsist on a diet of virtually all meat and fat yet avoid deficiency and heart diseases. Explains this paradox and discusses cultural and geographic influences on diet. The Inuit diet is compared with a typical American diet and the diet recommended by the U.S. Department of Agriculture in a laboratory exercise that measures dietary fat.…

"Macho Men" and Preventive Health Care: Implications for Older Men in Different Social Classes

ERIC Educational Resources Information Center

Springer, Kristen W.; Mouzon, Dawne M.

2011-01-01

The gender paradox in mortality--where men die earlier than women despite having more socioeconomic resources--may be partly explained by men's lower levels of preventive health care. Stereotypical notions of masculinity reduce preventive health care; however, the relationship between masculinity, socioeconomic status (SES), and preventive health…

Making Failure Matter: Enacting No Child Left Behind's Standards, Accountabilities, and Classifications

ERIC Educational Resources Information Center

Koyama, Jill P.

2012-01-01

This article ethnographically examines the paradoxical situation in which one high-achieving New York City public school is "constructed" as failing when No Child Left Behind (NCLB) assessments are miscalculated. Drawing upon actor-network theory (ANT)--a perspective that aims to explain how people, their ideas, and the material objects…

Heritability for Adolescent Antisocial Behavior Differs with Socioeconomic Status: Gene-Environment Interaction

ERIC Educational Resources Information Center

Tuvblad, Catherine; Grann, Martin; Lichtenstein, Paul

2006-01-01

Background: Socioeconomic status is often assumed to be of importance for the development of antisocial behavior, yet it explains only a fraction of the variance. One explanation for this paradox could be that socioeconomic status moderates the influence of genetic and environmental effects on antisocial behavior. Method: TCHAD is a Swedish…

DNA Sequence-Mediated, Evolutionarily Rapid Redistribution of Meiotic Recombination Hotspots

PubMed Central

Wahls, Wayne P.; Davidson, Mari K.

2011-01-01

Hotspots regulate the position and frequency of Spo11 (Rec12)-initiated meiotic recombination, but paradoxically they are suicidal and are somehow resurrected elsewhere in the genome. After the DNA sequence-dependent activation of hotspots was discovered in fission yeast, nearly two decades elapsed before the key realizations that (A) DNA site-dependent regulation is broadly conserved and (B) individual eukaryotes have multiple different DNA sequence motifs that activate hotspots. From our perspective, such findings provide a conceptually straightforward solution to the hotspot paradox and can explain other, seemingly complex features of meiotic recombination. We describe how a small number of single-base-pair substitutions can generate hotspots de novo and dramatically alter their distribution in the genome. This model also shows how equilibrium rate kinetics could maintain the presence of hotspots over evolutionary timescales, without strong selective pressures invoked previously, and explains why hotspots localize preferentially to intergenic regions and introns. The model is robust enough to account for all hotspots of humans and chimpanzees repositioned since their divergence from the latest common ancestor. PMID:22084420

The Hispanic Paradox and Predictors of Mortality in an Aging Bi-ethnic Cohort of Mexican Americans and European Americans: The San Antonio Longitudinal Study of Aging

PubMed Central

Espinoza, Sara E.; Jung, Inkyung; Hazuda, Helen

2013-01-01

OBJECTIVES To examine predictors of mortality in aging Mexican Americans (MAs) and European Americans (EAs). DESIGN Longitudinal, observational cohort study. SETTING Socioeconomically diverse neighborhoods in San Antonio, Texas. PARTICIPANTS Three hundred and ninety-four MA and 355 EA community-dwelling older adults (65+) who completed the baseline examination (1992–96) of the San Antonio Longitudinal Study of Aging (SALSA) and for whom vital status was ascertained over an average 8.2 years of follow-up. MEASUREMENTS Ethnic group was classified using a validated algorithm. Hazards ratios (HR) for mortality were estimated using Cox proportional hazards models with age, sex, ethnic group, education, income, frailty, diabetes with and without complications, comorbidity, cognition, depressive symptoms, and body mass index included as predictors in sequential models. RESULTS At baseline, MAs had higher prevalence of diabetes and frailty and lower socioeconomic status (SES) compared to EAs. The age- and sex-adjusted ethnic HR (MA vs. EA) for mortality was 1.54 (95% CI: 1.17–2.03). After adjusting for SES, the ethnic HR was no longer significant (HR = 1.16, 95% CI: 0.83–1.61). In the final model, comorbidity, diabetes with complications, depressive symptoms, and cognitive impairment were significant independent risk factors for mortality. CONCLUSION Contrary to the Hispanic paradox, MAs were at increased risk of mortality. Moreover, this ethnic disparity was largely explained by SES differences. Significant independent predictors of mortality, regardless of ethnic group, included diabetes with complications, comorbidity, depressive symptoms and cognitive impairment. Mortality reduction in older MAs requires attention to both socioeconomic disparities and disease factors. PMID:24000922

The nature-disorder paradox: A perceptual study on how nature is disorderly yet aesthetically preferred.

PubMed

Kotabe, Hiroki P; Kardan, Omid; Berman, Marc G

2017-08-01

Natural environments have powerful aesthetic appeal linked to their capacity for psychological restoration. In contrast, disorderly environments are aesthetically aversive, and have various detrimental psychological effects. But in our research, we have repeatedly found that natural environments are perceptually disorderly. What could explain this paradox? We present 3 competing hypotheses: the aesthetic preference for naturalness is more powerful than the aesthetic aversion to disorder (the nature-trumps-disorder hypothesis ); disorder is trivial to aesthetic preference in natural contexts (the harmless-disorder hypothesis ); and disorder is aesthetically preferred in natural contexts (the beneficial-disorder hypothesis ). Utilizing novel methods of perceptual study and diverse stimuli, we rule in the nature-trumps-disorder hypothesis and rule out the harmless-disorder and beneficial-disorder hypotheses. In examining perceptual mechanisms, we find evidence that high-level scene semantics are both necessary and sufficient for the nature-trumps-disorder effect. Necessity is evidenced by the effect disappearing in experiments utilizing only low-level visual stimuli (i.e., where scene semantics have been removed) and experiments utilizing a rapid-scene-presentation procedure that obscures scene semantics. Sufficiency is evidenced by the effect reappearing in experiments utilizing noun stimuli which remove low-level visual features. Furthermore, we present evidence that the interaction of scene semantics with low-level visual features amplifies the nature-trumps-disorder effect-the effect is weaker both when statistically adjusting for quantified low-level visual features and when using noun stimuli which remove low-level visual features. These results have implications for psychological theories bearing on the joint influence of low- and high-level perceptual inputs on affect and cognition, as well as for aesthetic design. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Geology and total petroleum systems of the Paradox Basin, Utah, Colorado, New Mexico, and Arizona

USGS Publications Warehouse

Whidden, Katherine J.; Lillis, Paul G.; Anna, Lawrence O.; Pearson, Krystal M.; Dubiel, Russell F.

2014-01-01

The most studied source intervals are the Pennsylvanian black shales that were deposited during relative high stands in an otherwise evaporitic basin. These black shales are the source for most of the discovered hydrocarbons in the Paradox Basin. A second oil type can be traced to either a Mississippian or Permian source rock to the west, and therefore requires long-distance migration to explain its presence in the basin. Upper Cretaceous continental to nearshore-marine sandstones are interbedded with coal beds that have recognized coalbed methane potential. Precambrian and Devonian TPSs are considered hypothetical, as both are known to have organic-rich intervals, but no discovered hydrocarbons have been definitively typed back to either of these units.

Metabolic Rate Regulation by the Renin-Angiotensin System: Brain vs. Body

PubMed Central

Grobe, Justin L.; Rahmouni, Kamal; Liu, Xuebo; Sigmund, Curt D.

2013-01-01

Substantial evidence supports a role for the renin-angiotensin system (RAS) in the regulation of metabolic function, but an apparent paradox exists where genetic or pharmacological inhibition of the RAS occasionally have similar physiological effects as chronic angiotensin infusion. Similarly, while RAS targeting in animal models has robust metabolic consequences, effects in humans are more subtle. Here we review the data supporting a role for the RAS in metabolic rate regulation and propose a model where the local brain RAS works in opposition to the peripheral RAS, thus helping to explain the paradoxically similar effects of RAS supplementation and inhibition. Selectively modulating the peripheral RAS or brain RAS may thus provide a more effective treatment paradigm for obesity and obesity-related disorders. PMID:22491893

The lunar apatite paradox.

PubMed

Boyce, J W; Tomlinson, S M; McCubbin, F M; Greenwood, J P; Treiman, A H

2014-04-25

Recent discoveries of water-rich lunar apatite are more consistent with the hydrous magmas of Earth than the otherwise volatile-depleted rocks of the Moon. Paradoxically, this requires H-rich minerals to form in rocks that are otherwise nearly anhydrous. We modeled existing data from the literature, finding that nominally anhydrous minerals do not sufficiently fractionate H from F and Cl to generate H-rich apatite. Hydrous apatites are explained as the products of apatite-induced low magmatic fluorine, which increases the H/F ratio in melt and apatite. Mare basalts may contain hydrogen-rich apatite, but lunar magmas were most likely poor in hydrogen, in agreement with the volatile depletion that is both observed in lunar rocks and required for canonical giant-impact models of the formation of the Moon.

Corporate Diversity Programs and Gender Inequality in the Oil and Gas Industry.

PubMed

Williams, Christine L; Kilanski, Kristine; Muller, Chandra

2014-11-01

Since the 1980s, major U.S. corporations have embraced diversity as a management strategy to increase the number of women in top jobs. Diversity management programs include targeted recruitment, hiring, and promotions policies; mentoring programs; affinity groups; and diversity training. Few of these programs have proven effective in achieving gender diversity in the corporate world, despite their widespread popularity. To explore the reasons for this, the authors investigate the experiences of women scientists in the oil and gas industry who are targeted by these programs. In-depth interviews reveal possible reasons why these programs fail to achieve their intended goals. The authors find that these programs can paradoxically reinforce gender inequality and male dominance in the industry. The authors discuss alternative approaches for addressing gender inequality in work organizations and conclude with implications of their findings for corporate approaches to promoting diversity and for future research.

Corporate Diversity Programs and Gender Inequality in the Oil and Gas Industry

PubMed Central

Williams, Christine L.; Kilanski, Kristine; Muller, Chandra

2014-01-01

Since the 1980s, major U.S. corporations have embraced diversity as a management strategy to increase the number of women in top jobs. Diversity management programs include targeted recruitment, hiring, and promotions policies; mentoring programs; affinity groups; and diversity training. Few of these programs have proven effective in achieving gender diversity in the corporate world, despite their widespread popularity. To explore the reasons for this, the authors investigate the experiences of women scientists in the oil and gas industry who are targeted by these programs. In-depth interviews reveal possible reasons why these programs fail to achieve their intended goals. The authors find that these programs can paradoxically reinforce gender inequality and male dominance in the industry. The authors discuss alternative approaches for addressing gender inequality in work organizations and conclude with implications of their findings for corporate approaches to promoting diversity and for future research. PMID:25558125

Williams' paradox and the role of phenotypic plasticity in sexual systems.

PubMed

Leonard, Janet L

2013-10-01

As George Williams pointed out in 1975, although evolutionary explanations, based on selection acting on individuals, have been developed for the advantages of simultaneous hermaphroditism, sequential hermaphroditism and gonochorism, none of these evolutionary explanations adequately explains the current distribution of these sexual systems within the Metazoa (Williams' Paradox). As Williams further pointed out, the current distribution of sexual systems is explained largely by phylogeny. Since 1975, we have made a great deal of empirical and theoretical progress in understanding sexual systems. However, we still lack a theory that explains the current distribution of sexual systems in animals and we do not understand the evolutionary transitions between hermaphroditism and gonochorism. Empirical data, collected over the past 40 years, demonstrate that gender may have more phenotypic plasticity than was previously realized. We know that not only sequential hermaphrodites, but also simultaneous hermaphrodites have phenotypic plasticity that alters sex allocation in response to social and environmental conditions. A focus on phenotypic plasticity suggests that one sees a continuum in animals between genetically determined gonochorism on the one hand and simultaneous hermaphroditism on the other, with various types of sequential hermaphroditism and environmental sex determination as points along the spectrum. Here I suggest that perhaps the reason we have been unable to resolve Williams' Paradox is because the problem was not correctly framed. First, because, for example, simultaneous hermaphroditism provides reproductive assurance or dioecy ensures outcrossing does not mean that there are no other evolutionary paths that can provide adaptive responses to those selective pressures. Second, perhaps the question we need to ask is: What selective forces favor increased versus reduced phenotypic plasticity in gender expression? It is time to begin to look at the question of sexual system as one of understanding the timing and degree of phenotypic plasticity in gender expression in the life history in terms of selection acting on a continuum, rather than on a set of discrete sexual systems.

My self as an other: on autoimmunity and "other" paradoxes.

PubMed

Cohen, E

2004-06-01

The rubric autoimmunity currently encompasses sixty to seventy diverse illnesses which affect many of the tissues of the human body. Western medical practice asserts that the crisis known as autoimmune disease arises when a biological organism compromises its own integrity by misrecognising parts of itself as other than itself and then seeks to eliminate these unrecognised and hence antagonistic aspects of itself. That is, autoimmune illnesses seem to manifest the contradictory and sometimes deadly proposition that the "identity": body/self both is and is not "itself". Based on the assumption that under normal circumstances "the self" ought to coincide naturally with "the body"-or at the very least the self ought to inhabit the living location of the body more or less unproblematically-this scientific paradigm depicts autoimmune illness as a vital paradox. Yet for those of us who have lived through the experience of an autoimmune crisis, the living paradox that we embody may also lead us to question the basis upon which these medical assumptions rest. This essay raises some of these questions.

Further Evidence of an Engagement-Achievement Paradox among U.S. High School Students

ERIC Educational Resources Information Center

Shernoff, David J.; Schmidt, Jennifer A.

2008-01-01

Achievement, engagement, and students' quality of experience were compared by racial and ethnic group in a sample of students (N = 586) drawn from 13 high schools with diverse ethnic and socioeconomic student populations. Using the Experience Sampling Method (ESM), 3,529 samples of classroom experiences were analyzed along with self-reported…

"Marriage Is More than Being Together": The Meaning of Marriage for Young Adults

ERIC Educational Resources Information Center

Kefalas, Maria J.; Furstenberg, Frank F.; Carr, Patrick J.; Napolitano, Laura

2011-01-01

Based on 424 qualitative interviews with a racially, ethnically, and socio-economically diverse population of young people ranging in age from 21 to 38, the authors ponder the paradox of the evolving role for contemporary marriage within the developmental perspective of the transition to adulthood. The authors identify two groups: marriage…

Exploring the "Obesity Paradox" as a Correlate of Cognitive and Physical Function in Community-dwelling Black and White Older Adults.

PubMed

Skinner, Jeannine S; Abel, Willie Mae; McCoy, Katryna; Wilkins, Consuelo H

2017-01-01

The obesity paradox has been documented in aged populations, yet it remains unclear if this paradox persists for physical and cognitive outcomes in community-dwelling older adult populations. Our study examines associations between body mass index (BMI) classification, cognitive function, and physical function. We also investigate whether these associations are modified by race or age. Cross-sectional study. Senior residential sites and community centers in Saint Louis, Missouri. Study participants included 331 adults, aged >55 years. Age was stratified into young-old (aged 55-74 years) and older (aged ≥75 years). Physical function was measured using the mini-Physical Performance Test (mini-PPT) and grip strength. Cognitive function was assessed with the Short Blessed Test (SBT) and the Trail Making Tests (TMT-A and TMT-B) performance. Older adults who were obese had significantly better cognitive flexibility (TMT-B) performance than normal weight older adults (P=.02), and this association was not influenced by age or race. Adiposity was not associated with psychomotor speed (TMT-A), general cognition (SBT), or measures of physical function (Ps>.05). In a diverse sample of community-dwelling older adults, we found partial support for the controversial obesity paradox. Our results suggest excess adiposity may be protective for executive function processes. Future research is needed to examine the underlying physiological processes linking adiposity to executive function in older adults.

Does Selective Migration Explain the Hispanic Paradox?: A Comparative Analysis of Mexicans in the U.S. and Mexico

PubMed Central

Bostean, Georgiana

2014-01-01

Latino immigrants, particularly Mexican, have some health advantages over U.S.-born Mexicans and Whites. Because of their lower socioeconomic status, this phenomenon has been called the epidemiologic “Hispanic Paradox.” While cultural theories have dominated explanations for the Paradox, the role of selective migration has been inadequately addressed. This study is among the few to combine Mexican and U.S. data to examine health selectivity in activity limitation, self-rated health, and chronic conditions among Mexican immigrants, ages 18 and over. Drawing on theories of selective migration, this study tested the “healthy migrant” and “salmon-bias” hypotheses by comparing the health of Mexican immigrants in the U.S. to non-migrants in Mexico, and to return migrants in Mexico. Results suggest that there are both healthy migrant and salmon-bias effects in activity limitation, but not other health aspects. In fact, consistent with prior research, immigrants are negatively selected on self-rated health. Future research should consider the complexities of migrants’ health profiles and examine selection mechanisms alongside other factors such as acculturation. PMID:22618355

Does selective migration explain the Hispanic paradox? A comparative analysis of Mexicans in the U.S. and Mexico.

PubMed

Bostean, Georgiana

2013-06-01

Latino immigrants, particularly Mexican, have some health advantages over U.S.-born Mexicans and Whites. Because of their lower socioeconomic status, this phenomenon has been called the epidemiologic "Hispanic Paradox." While cultural theories have dominated explanations for the Paradox, the role of selective migration has been inadequately addressed. This study is among the few to combine Mexican and U.S. data to examine health selectivity in activity limitation, self-rated health, and chronic conditions among Mexican immigrants, ages 18 and over. Drawing on theories of selective migration, this study tested the "healthy migrant" and "salmon-bias" hypotheses by comparing the health of Mexican immigrants in the U.S. to non-migrants in Mexico, and to return migrants in Mexico. Results suggest that there are both healthy migrant and salmon-bias effects in activity limitation, but not other health aspects. In fact, consistent with prior research, immigrants are negatively selected on self-rated health. Future research should consider the complexities of migrants' health profiles and examine selection mechanisms alongside other factors such as acculturation.

Mate choice for genetic quality when environments vary: suggestions for empirical progress.

PubMed

Bussière, Luc F; Hunt, John; Stölting, Kai N; Jennions, Michael D; Brooks, Robert

2008-09-01

Mate choice for good-genes remains one of the most controversial evolutionary processes ever proposed. This is partly because strong directional choice should theoretically deplete the genetic variation that explains the evolution of this type of female mating preference (the so-called lek paradox). Moreover, good-genes benefits are generally assumed to be too small to outweigh opposing direct selection on females. Here, we review recent progress in the study of mate choice for genetic quality, focussing particularly on the potential for genotype by environment interactions (GEIs) to rescue additive genetic variation for quality, and thereby resolve the lek paradox. We raise five questions that we think will stimulate empirical progress in this field, and suggest directions for research in each area: (1) How is condition-dependence affected by environmental variation? (2) How important are GEIs for maintaining additive genetic variance in condition? (3) How much do GEIs reduce the signalling value of male condition? (4) How does GEI affect the multivariate version of the lek paradox? (5) Have mating biases for high-condition males evolved because of indirect benefits?

From Chinese model to U.S. symptoms: the paradox of China's health system.

PubMed

Gong, Sen; Walker, Alan; Shi, Guang

2007-01-01

This article explains the paradox of China's recent failure to secure significant improvements in the health of its people despite once being the envy of the developing world for its successful health policies and its huge sustained increases in both economic growth and expenditure on health care. The authors begin with an outline of the organization and financing of China's health services, then track the recent upward trend in health spending and examine its structural features in conjunction with those of spending in other, comparable countries. The main discussion consists of an evaluation of health service system performance in China during the reform era and an explanation of its health paradox. The key elements in this account are the waste of resources, the neglect of proven health interventions, and the lack of fairness in allocation of medical resources--all of which are underpinned by the neoliberal orientation of policy in the reform era. The authors conclude with some policy proposals centering on the restoration of social justice in the health system. The article draws on material previously unavailable in English.

The Effects of Dynamical Rates on Species Coexistence in a Variable Environment: The Paradox of the Plankton Revisited.

PubMed

Li, Lina; Chesson, Peter

2016-08-01

Hutchinson's famous hypothesis for the "paradox of the plankton" has been widely accepted, but critical aspects have remained unchallenged. Hutchinson argued that environmental fluctuations would promote coexistence when the timescale for environmental change is comparable to the timescale for competitive exclusion. Using a consumer-resource model, we do find that timescales of processes are important. However, it is not the time to exclusion that must be compared with the time for environmental change but the time for resource depletion. Fast resource depletion, when resource consumption is favored for different species at different times, strongly promotes coexistence. The time for exclusion is independent of the rate of resource depletion. Therefore, the widely believed predictions of Hutchinson are misleading. Fast resource depletion, as determined by environmental conditions, ensures strong coupling of environmental processes and competition, which leads to enhancement over time of intraspecific competition relative to interspecific competition as environmental shifts favor different species at different times. This critical coupling is measured by the covariance between environment and competition. Changes in this quantity as densities change determine the stability of coexistence and provide the key to rigorous analysis, both theoretically and empirically, of coexistence in a variable environment. These ideas apply broadly to diversity maintenance in variable environments whether the issue is species diversity or genetic diversity and competition or apparent competition.

The High Cost "of" Convenience: Satisfying Short-Term Needs Erodes Long-Term Learning

ERIC Educational Resources Information Center

Zimmerman, Dian P.

2015-01-01

Novel ways of thinking often come from the cross-pollination of language from other professions. The term "satisficing" is one such term and is a powerful construct that fuses two concepts, satisfy and suffice, together to explain something new. Satisficing describes the often-paradoxical results that plague decision making. Depending on…

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

ERIC Educational Resources Information Center

Taylor, Wendy; Stacey, Kaye

2014-01-01

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

Effect of MUC1 Expression on EGFR Endocytosis and Degradation in Human Breast Cancer Cell Lines

DTIC Science & Technology

2007-04-01

AR), heparin-binding EGF (HB-EGF), betacellulin (BTC), epiregulin ( EPR ), and epigen [reviewed in (Schroeder & Lee, 1997) and (Strachan et al., 2001...of erbB1, it also promotes its internalization. This apparent paradox may be explained by one of two non-exclusive hypotheses. The first is that

Generics Pricing: The Greek Paradox.

PubMed

Karafyllis, Ioannis; Variti, Lamprini

2017-01-01

This paper explains and develops a methodological framework to help evaluate the performance of generic pharmaceutical policies and the correct evaluation of generics sales. Until today erroneous recording of generics does not help proper pricing and their penetration in the Greek market. This classifies Greece on the outliners in every study or comparison that is referred on papers or studies.

Explicating the Influences That Explain Intention to Use Technology among English Teachers in China

ERIC Educational Resources Information Center

Teo, Timothy; Huang, Fang; Hoi, Cathy Ka Weng

2018-01-01

Given the paradox between pervasive promotion of technology use in English teaching and lack of studies about teachers' technology acceptance in China, this study aims to examine intentions of English teachers in China to use technology in their classroom teaching. Based on the technology acceptance model, eight variables including perceived…

A Model of Twice-Exceptionality: Explaining and Defining the Apparent Paradoxical Combination of Disability and Giftedness in Childhood

ERIC Educational Resources Information Center

Ronksley-Pavia, Michelle

2015-01-01

The literature on twice-exceptionality suggests one of the main problems facing twice-exceptional children is that there is no consensus on the definition of the terms "disability" or "giftedness" and, consequently, the term "twice-exceptional". Endeavoring to define these specific terms loops back on itself to…

THE EXPOSURE PARADOX IN PARTICULATE MATTER COMMUNITY TIME-SERIES EPIDEMIOLOGY: CAN AMBIENT CONCENTRATIONS OF PM BE USED AS A SURROGATE FOR PERSONAL EXPOSURE TO PM ?

EPA Science Inventory

Objective: Explain why epidemiologic studies find a statistically significant relationship between ambient concentrations of PM and health effects even though only a near-zero correlation is found between ambient concentrations of PM and personal exposures to PM. Method: Consider...

The Obesity Paradox in Recurrent Attacks of Gout in Observational Studies: Clarification and Remedy

PubMed Central

Nguyen, Uyen-Sa D. T.; Zhang, Yuqing; Louie-Gao, Qiong; Niu, Jingbo; Felson, David T.; LaValley, Michael P.; Choi, Hyon K.

2016-01-01

Objective Obesity is strongly associated with incident gout risk; its association with risk of recurrent gout attacks has been null or weak, constituting an obesity paradox. We sought to demonstrate and overcome the methodologic issues associated with the obesity paradox for risk of recurrent gout attacks. Methods Using the MRFIT database, we decomposed the total effect of obesity into its direct and indirect (i.e., mediated) effects using marginal structural models. We also estimated the total effect of BMI change from baseline among incident gout patients. Results Of 11,816 gout-free subjects at baseline, we documented 408 incident gout cases, with 132 developing recurrent gout attacks over a 7-year follow-up. The adjusted odds ratio (OR) for incident gout among obese individuals was 2.6, while that for recurrent gout attacks among gout patients was 0.98 (i.e., the obesity paradox). These ORs correlated well with the ORs for the indirect and direct effects of obesity on risk of recurrent gout attacks (i.e., 2.83 and 0.98, respectively). Compared with no BMI change, the OR of losing vs. gaining >5% of baseline BMI was 0.61 and 1.60 for recurrent gout attacks, respectively (P for trend <0.01), suggesting a dose-response association. Conclusion The obesity paradox for risk of recurrent gout attacks is explained by the absence of the direct effect, which is often measured in conventional analyses and misinterpreted as the intended total effect of interest. In contrast, the BMI change analysis correctly estimated the intended total effect of BMI, and revealed a dose-response relationship. PMID:27331767

The current deconstruction of paradoxes: one sign of the ongoing methodological "revolution".

PubMed

Porta, Miquel; Vineis, Paolo; Bolúmar, Francisco

2015-10-01

The current deconstruction of paradoxes is one among several signs that a profound renewal of methods for clinical and epidemiological research is taking place; perhaps for some basic life sciences as well. The new methodological approaches have already deconstructed and explained long puzzling apparent paradoxes, including the (non-existent) benefits of obesity in diabetics, or of smoking in low birth weight. Achievements of the new methods also comprise the elucidation of the causal structure of long-disputed and highly complex questions, as Berkson's bias and Simpson's paradox, and clarifying reasons for deep controversies, as those on estrogens and endometrial cancer, or on adverse effects of hormone replacement therapy. These are signs that the new methods can go deeper and beyond the methods in current use. A major example of a highly relevant idea is: when we condition on a common effect of a pair of variables, then a spurious association between such pair is likely. The implications of these ideas are potentially vast. A substantial number of apparent paradoxes may simply be the result of collider biases, a source of selection bias that is common not just in epidemiologic research, but in many types of research in the health, life, and social sciences. The new approaches develop a new framework of concepts and methods, as collider, instrumental variables, d-separation, backdoor path and, notably, Directed Acyclic Graphs (DAGs). The current theoretical and methodological renewal-or, perhaps, "revolution"-may be changing deeply how clinical and epidemiological research is conceived and performed, how we assess the validity and relevance of findings, and how causal inferences are made. Clinical and basic researchers, among others, should get acquainted with DAGs and related concepts.

Engaging Gatekeepers, Optimizing Decision Making, and Mitigating Bias: Design Specifications for Systemic Diversity Interventions.

PubMed

Vinkenburg, Claartje J

2017-06-01

In this contribution to the Journal of Applied Behavioral Science Special Issue on Understanding Diversity Dynamics in Systems: Social Equality as an Organization Change Issue, I develop and describe design specifications for systemic diversity interventions in upward mobility career systems, aimed at optimizing decision making through mitigating bias by engaging gatekeepers. These interventions address the paradox of meritocracy that underlies the surprising lack of diversity at the top of the career pyramid in these systems. I ground the design specifications in the limited empirical evidence on "what works" in systemic interventions. Specifically, I describe examples from interventions in academic settings, including a bias literacy program, participatory modeling, and participant observation. The design specifications, paired with inspirational examples of successful interventions, should assist diversity officers and consultants in designing and implementing interventions to promote the advancement to and representation of nondominant group members at the top of the organizational hierarchy.

Engaging Gatekeepers, Optimizing Decision Making, and Mitigating Bias: Design Specifications for Systemic Diversity Interventions

PubMed Central

Vinkenburg, Claartje J.

2017-01-01

In this contribution to the Journal of Applied Behavioral Science Special Issue on Understanding Diversity Dynamics in Systems: Social Equality as an Organization Change Issue, I develop and describe design specifications for systemic diversity interventions in upward mobility career systems, aimed at optimizing decision making through mitigating bias by engaging gatekeepers. These interventions address the paradox of meritocracy that underlies the surprising lack of diversity at the top of the career pyramid in these systems. I ground the design specifications in the limited empirical evidence on “what works” in systemic interventions. Specifically, I describe examples from interventions in academic settings, including a bias literacy program, participatory modeling, and participant observation. The design specifications, paired with inspirational examples of successful interventions, should assist diversity officers and consultants in designing and implementing interventions to promote the advancement to and representation of nondominant group members at the top of the organizational hierarchy. PMID:28546644

"Coming to a 'Place' near You?" The Politics and Possibilities of a Critical Pedagogy of Place-Based Education

ERIC Educational Resources Information Center

McInerney, Peter; Smyth, John; Down, Barry

2011-01-01

It may seem something of a paradox that in a globalised age where notions of interdependence, interconnectedness and common destinies abound, the "local", with its diversity of cultures, languages, histories and geographies, continues to exercise a powerful grip on the human imagination. The ties that bind us have global connections but…

From peds to paradoxes: Linkages between soil biota and their influences on ecological processes

Treesearch

David C. Coleman

2008-01-01

Soils and their biota have been studied by a variety of observational and experimental methods that have allowed biologists to infer their structural and functional interactions. Viewing progress made over the last 10 years, it is apparent that an increasing diversity of analytical and chemical methods are providing much more detailed information about feeding...

From Casual Work to Economic Security; the Paradoxical Case of Self-Employment

ERIC Educational Resources Information Center

Tremblay, Diane-Gabrielle

2008-01-01

The term "casual work" is not well defined in the literature and can include a diversity of types of employment. In this paper, we first present an introduction and definition of concepts related to job security and economic insecurity. Second, a view on the main labour market transformations, their causes and impacts, with more accent on…

Species diversity in the marine microturbellarian Astrotorhynchus bifidus sensu lato (Platyhelminthes: Rhabdocoela) from the Northeast Pacific Ocean.

PubMed

Van Steenkiste, Niels W L; Herbert, Elizabeth R; Leander, Brian S

2018-03-01

Increasing evidence suggests that many widespread species of meiofauna are in fact regional complexes of (pseudo-)cryptic species. This knowledge has challenged the 'Everything is Everywhere' hypothesis and also partly explains the meiofauna paradox of widespread nominal species with limited dispersal abilities. Here, we investigated species diversity within the marine microturbellarian Astrotorhynchus bifidus sensu lato in the Northeast Pacific Ocean. We used a multiple-evidence approach combining multi-gene (18S, 28S, COI) phylogenetic analyses, several single-gene and multi-gene species delimitation methods, haplotype networks and conventional taxonomy to designate Primary Species Hypotheses (PSHs). This included the development of rhabdocoel-specific COI barcode primers, which also have the potential to aid in species identification and delimitation in other rhabdocoels. Secondary Species Hypotheses (SSHs) corresponding to morphospecies and pseudo-cryptic species were then proposed based on the minimum consensus of different PSHs. Our results showed that (a) there are at least five species in the A. bifidus complex in the Northeast Pacific Ocean, four of which can be diagnosed based on stylet morphology, (b) the A. bifidus complex is a mixture of sympatric and allopatric species with regional and/or subglobal distributions, (c) sympatry occurs on local (sample sites), regional (Northeastern Pacific) and subglobal (Northern Atlantic, Arctic, Northeastern Pacific) scales. Mechanisms for this co-occurrence are still poorly understood, but we hypothesize they could include habitat differentiation (spatial and/or seasonal) and life history characteristics such as sexual selection and dispersal abilities. Our results also suggest the need for improved sampling and exploration of molecular markers to accurately map gene flow and broaden our understanding of species diversity and distribution of microturbellarians in particular and meiofauna in general. Copyright © 2017 Elsevier Inc. All rights reserved.

Galectins as self/non-self recognition receptors in innate and adaptive immunity: an unresolved paradox

PubMed Central

Vasta, Gerardo R.; Ahmed, Hafiz; Nita-Lazar, Mihai; Banerjee, Aditi; Pasek, Marta; Shridhar, Surekha; Guha, Prasun; Fernández-Robledo, José A.

2012-01-01

Galectins are characterized by their binding affinity for β-galactosides, a unique binding site sequence motif, and wide taxonomic distribution and structural conservation in vertebrates, invertebrates, protista, and fungi. Since their initial description, galectins were considered to bind endogenous (“self”) glycans and mediate developmental processes and cancer. In the past few years, however, numerous studies have described the diverse effects of galectins on cells involved in both innate and adaptive immune responses, and the mechanistic aspects of their regulatory roles in immune homeostasis. More recently, however, evidence has accumulated to suggest that galectins also bind exogenous (“non-self”) glycans on the surface of potentially pathogenic microbes, parasites, and fungi, suggesting that galectins can function as pattern recognition receptors (PRRs) in innate immunity. Thus, a perplexing paradox arises by the fact that galectins also recognize lactosamine-containing glycans on the host cell surface during developmental processes and regulation of immune responses. According to the currently accepted model for non-self recognition, PRRs recognize pathogens via highly conserved microbial surface molecules of wide distribution such as LPS or peptidoglycan (pathogen-associated molecular patterns; PAMPs), which are absent in the host. Hence, this would not apply to galectins, which apparently bind similar self/non-self molecular patterns on host and microbial cells. This paradox underscores first, an oversimplification in the use of the PRR/PAMP terminology. Second, and most importantly, it reveals significant gaps in our knowledge about the diversity of the host galectin repertoire, and the subcellular targeting, localization, and secretion. Furthermore, our knowledge about the structural and biophysical aspects of their interactions with the host and microbial carbohydrate moieties is fragmentary, and warrants further investigation. PMID:22811679

The Paradox of the Education Race: How to Win the Ranking Game by Sailing to Headwind

ERIC Educational Resources Information Center

Simola, Hannu; Rinne, Risto; Varjo, Janne; Kauko, Jaakko

2013-01-01

In this article, we experiment with the idea of combining path dependency, convergence and contingency in explaining Finnish distinctiveness in education policy and politics since the early 1990s. The focus of this article is on quality assurance and evaluation (QAE) in comprehensive schooling. We elaborate on and contextualise the Finnish QAE…

Modified Hawking Radiation from a Kerr-Newman Black Hole due to Back-Reaction

NASA Astrophysics Data System (ADS)

Liu, Bo; Wang, Gang; Liu, Wenbiao

Hawking radiation from a general Kerr-Newman black hole is investigated using Damour-Ruffini's method. Considering the back-reaction of particle's energy, charge and angular momentum to the spacetime, we obtain a modified nonthermal spectrum. Maybe the information loss paradox can be explained, furthermore, the result is also consistent with the result obtained using Parikh and Wilczek's method.

Why Do Sixty Percent of Young People Feel Their Compatriots Have Blind Faith in Foreign Things?

ERIC Educational Resources Information Center

Shunan, Xiao; Qin, Zhou

2011-01-01

Interview and survey data in China suggest a high degree of patriotism, and Western public opinion polls reveal that many people see China as the world's second most powerful country. Yet Chinese Internet surveys find that Chinese citizens still lack self-confidence in dealing with Westerners. The authors explain this seeming paradox by suggesting…

Explaining the Paradox: Perceived Instructor Benefits and Costs of Contributing to Massachusetts Institute of Technology OpenCourseWare

ERIC Educational Resources Information Center

Parker, Preston Paul

2011-01-01

This study examines perceived benefits and costs of instructors who contributed to the Massachusetts Institute of Technology (MIT) OpenCourseWare (OCW) project. While previous research has investigated the benefits and costs of OCW from the perspectives of the users and institution, the instructor's perspective is the focus of this qualitative…

Metatranscriptome analyses indicate resource partitioning between diatoms in the field.

PubMed

Alexander, Harriet; Jenkins, Bethany D; Rynearson, Tatiana A; Dyhrman, Sonya T

2015-04-28

Diverse communities of marine phytoplankton carry out half of global primary production. The vast diversity of the phytoplankton has long perplexed ecologists because these organisms coexist in an isotropic environment while competing for the same basic resources (e.g., inorganic nutrients). Differential niche partitioning of resources is one hypothesis to explain this "paradox of the plankton," but it is difficult to quantify and track variation in phytoplankton metabolism in situ. Here, we use quantitative metatranscriptome analyses to examine pathways of nitrogen (N) and phosphorus (P) metabolism in diatoms that cooccur regularly in an estuary on the east coast of the United States (Narragansett Bay). Expression of known N and P metabolic pathways varied between diatoms, indicating apparent differences in resource utilization capacity that may prevent direct competition. Nutrient amendment incubations skewed N/P ratios, elucidating nutrient-responsive patterns of expression and facilitating a quantitative comparison between diatoms. The resource-responsive (RR) gene sets deviated in composition from the metabolic profile of the organism, being enriched in genes associated with N and P metabolism. Expression of the RR gene set varied over time and differed significantly between diatoms, resulting in opposite transcriptional responses to the same environment. Apparent differences in metabolic capacity and the expression of that capacity in the environment suggest that diatom-specific resource partitioning was occurring in Narragansett Bay. This high-resolution approach highlights the molecular underpinnings of diatom resource utilization and how cooccurring diatoms adjust their cellular physiology to partition their niche space.

The tobacco paradox in acute coronary syndrome. The prior cessation of smoking as a marker of a better short-term prognosis.

PubMed

Bastos-Amador, P; Almendro-Delia, M; Muñoz-Calero, B; Blanco-Ponce, E; Recio-Mayoral, A; Reina-Toral, A; Cruz-Fernandez, J M; García-Alcántara, A; Hidalgo-Urbano, R; García-Rubira, J C

2016-01-01

The tobacco paradox is a phenomenon insufficiently explained by previous studies. This study analyses the prognostic role of prior or active smoking in patients with acute coronary syndrome. We obtained data from the ARIAM registry, between 2001 and 2012. The study included 42,827 patients with acute coronary syndrome (mean age, 65±13 years; 26.4% women). The influence of smoking and that of being an ex-smoker on mortality was analysed using a multivariate analysis. The smokers were younger, were more often men, had less diabetes, hypertension and prior history of heart failure, stroke, arrhythmia and renal failure and more frequently had ST-elevation and a family history of smoking. The ex-smokers had more dyslipidaemia and history of angina, myocardial infarction, ischemic heart disease, peripheral vasculopathy and chronic bronchial disease. Smokers and ex-smokers less frequently developed cardiogenic shock (smokers 4.2%, ex-smokers 4.7% and nonsmokers 6.9%, P<.001). Hospital mortality was 7.8% for the nonsmokers, 4.9% for the ex-smokers and 3.1% for the smokers (P<.001). In the multivariate analysis, the smoker factor lost its influence in the prognosis (-0.26%, p=.52 using an inverse probability calculation; and+0.26%, P=.691 using a propensity analysis). However, the exsmoker factor showed a significant reduction in mortality in both tests (-2.4% in the inverse probability analysis, P<.001; and -1.5% in the propensity analysis, P=.005). The tobacco paradox is a finding that could be explained by other prognostic factors. Smoking cessation prior to hospitalization for acute coronary syndrome is associated with a better prognosis. Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Medicina Interna (SEMI). All rights reserved.

Differences in neurohormonal activity partially explain the obesity paradox in patients with heart failure: The role of sympathetic activation.

PubMed

Farré, Núria; Aranyó, Júlia; Enjuanes, Cristina; Verdú-Rotellar, José María; Ruiz, Sonia; Gonzalez-Robledo, Gina; Meroño, Oona; de Ramon, Marta; Moliner, Pedro; Bruguera, Jordi; Comin-Colet, Josep

2015-02-15

Obese patients with chronic Heart Failure (HF) have better outcome than their lean counterparts, although little is known about the pathophysiology of this obesity paradox. Our aim was to evaluate the hypothesis that patients with chronic HF and obesity (defined as body mass index (BMI)≥30kg/m(2)), may have an attenuated neurohormonal activation in comparison with non-obese patients. The present study is the post-hoc analysis of a cohort of 742 chronic HF patients from a single-center study evaluating sympathetic activation by measuring baseline levels of norepinephrine (NE). Obesity was present in 33% of patients. Higher BMI and obesity were significantly associated with lower NE levels in multivariable linear regression models adjusted for covariates (p<0.001). Addition to NE in multivariate Cox proportional hazard models attenuated the prognostic impact of BMI in terms of outcomes. Finally, when we explored the prognosis impact of raised NE levels (>70th percentile) carrying out a separate analysis in obese and non-obese patients we found that in both groups NE remained a significant independent predictor of poorer outcomes, despite the lower NE levels in patients with chronic HF and obesity: all-cause mortality hazard ratio=2.37 (95% confidence interval, 1.14-4.94) and hazard ratio=1.59 (95% confidence interval, 1.05-2.4) in obese and non-obese respectively; and cardiovascular mortality hazard ratio=3.08 (95% confidence interval, 1.05-9.01) in obese patients and hazard ratio=2.08 (95% confidence interval, 1.42-3.05) in non-obese patients. Patients with chronic HF and obesity have significantly lower sympathetic activation. This finding may partially explain the obesity paradox described in chronic HF patients. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Restricted utilization of germ-line VH genes in rabbits: implications for inheritance of VH allotypes and generation of antibody diversity.

PubMed

Knight, K L; Becker, R S; DiPietro, L A

1991-01-01

The presence of inherited VH region allotypic specificities, a1, a2 or a3, on nearly all rabbit immunoglobulins has presented a paradox. We know the germline contains hundreds of VH genes, and if we assume that most of these are used in the generation of antibody diversity, then we must ask how have the a allotype-encoding regions been maintained over time? On the other hand, if we assume that only one (or a small number) of these VH gene(s) is (are) used in VDJ gene rearrangements, then, how is antibody diversity generated? To address these questions, we have cloned and determined the nucleotide sequence of the 3'-most germline VH genes from the a1, a2 and a3 chromosomes and shown in each case that the 3'-most H gene, VH1-a1, VH1-a2, or VH1-a3, encodes an a1, a2 or a3 VH region, respectively. Analysis of rearranged VDJ genes from leukemic B cells showed that VH1 was utilized in these rearrangements. Based on these data, we propose that the allelic inheritance of the VH allotypes is explained by the preferential usage of the VH1 gene in VDJ rearrangements. Support for this hypothesis was obtained from analysis of the mutant rabbit Alicia in which most serum Ig molecules do not have VHa allotypic specificities, but instead have so-called VHa-negative Ig molecules. In this rabbit, VH1 is not expressed as it has been deleted. Analysis of cDNA clones from spleen of Alicia rabbits suggests that the expressed VHa-negative molecules also are encoded by a single germline VH gene. Thus, we suggest that nearly all rabbit VH regions are encoded by one to two germline VH genes and that antibody diversity is generated primarily by somatic hypermutation and gene conversion.

Freshwater ecosystems and aquatic insects: a paradox in biological invasions.

PubMed

Fenoglio, Stefano; Bonada, Núria; Guareschi, Simone; López-Rodríguez, Manuel J; Millán, Andrés; Tierno de Figueroa, J Manuel

2016-04-01

Biological invasions have increased significantly in response to global change and constitute one of the major causes of biodiversity loss. Insects make up a large fraction of invasive species, in general, and freshwaters are among the most invaded ecosystems on our planet. However, even though aquatic insects dominate most inland waters, have unparalleled taxonomic diversity and occupy nearly all trophic niches, there are almost no invasive insects in freshwaters. We present some hypotheses regarding why aquatic insects are not common among aquatic invasive organisms, suggesting that it may be the result of a suite of biological, ecological and anthropogenic factors. Such specific knowledge introduces a paradox in the current scientific discussion on invasive species; therefore, a more in-depth understanding could be an invaluable aid to disentangling how and why biological invasions occur. © 2016 The Author(s).

An ecological paradox: high species diversity and low position of the upper forest line in the Andean Depression.

PubMed

Peters, Thorsten; Braeuning, Achim; Muenchow, Jannes; Richter, Michael

2014-06-01

Systematic investigations of the upper forest line (UFL) primarily concentrate on mid and high latitudes of the Northern Hemisphere, whereas studies of Neotropical UFLs are still fragmentary. This article outlines the extraordinary high tree diversity at the UFL within the Andean Depression and unravels the links between the comparatively low position of the local UFL, high tree-species diversity, and climate. On the basis of Gentry's rapid inventory methodology for the tropics, vegetation sampling was conducted at 12 UFL sites, and local climate (temperature, wind, precipitation, and soil moisture) was investigated at six sites. Monotypic forests dominated by Polylepis were only found at the higher located margins of the Andean Depression while the lower situated core areas were characterized by a species-rich forest, which lacked the elsewhere dominant tree-species Polylepis. In total, a remarkably high tree-species number of 255 tree species of 40 different plant families was found. Beta-diversity was also high with more than two complete species turnovers. A non-linear relationship between the floristic similarity of the investigated study sites and elevation was detected. Temperatures at the investigated study sites clearly exceeded 5.5°C, the postulated threshold value for the upper tree growth limit in the tropics. Instead, quasi-permanent trade winds, high precipitation amounts, and high soil water contents affect the local position of the UFL in a negative way. Interestingly, most of the above-mentioned factors are also contributing to the high species richness. The result is a combination of a clearly marked upper forest line depression combined with an extraordinary forest line complexity, which was an almost unknown paradox.

Obesity Paradox in Lung Cancer Prognosis: Evolving Biological Insights and Clinical Implications.

PubMed

Zhang, Xueli; Liu, Yamin; Shao, Hua; Zheng, Xiao

2017-10-01

The survival rate of lung cancer remains low despite the progress of surgery and chemotherapy. With the increasing comorbidity of obesity in patients with lung cancer, new challenges are emerging in the management of this patient population. A key issue of interest is the prognostic effect of obesity on surgical and chemotherapeutic outcomes in patients with lung cancer, which is fueled by the growing observation of survival benefits in overweight or obese patients. This unexpected inverse relationship between obesity and lung cancer mortality, called the obesity paradox, remains poorly understood. The evolving insights into the heterogeneity of obesity phenotypes and associated biological connections with lung cancer progression in recent years may help explain some of the seemingly paradoxical relationship, and well-designed clinical studies looking at the causal role of obesity-associated molecules are expected. Here, we examine potential biological mechanisms behind the protective effects of obesity in lung cancer. We highlight the need to clarify the clinical implications of this relationship toward an updated intervention strategy in the clinical care of patients with lung cancer and obesity. Copyright © 2017 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.

Towards a dialogue between utilitarianism and medicine.

PubMed

Barilan, Y Michael

2004-01-01

Utilitarianism focuses on the optimization of personal well being in ways that seems to make the practice of medicine irrelevant to the well being of the practitioners, unless given external incentives such as money or honor. Care based on indirect incentives is considered inferior to care motivated internally. This leads to the paradox of utilitarian care. Following Nozick's conceptual Pleasure Machine it is argued that in addition to the promotion of personal well being, people care about fulfilling their well being in a world which is real, just, good, and beautiful. Complete mechanization of social and personal life in accordance with a strict utilitarian regime is also incompatible with the kind of world people desire, even if it promises more fulfillments in terms of personal well being. This explains the so-called Taurek-Parfit paradox, according to which sometimes ethics seems "to count the numbers" and sometimes not. The very pursuit of utilitarianism does not contribute to any personal life plan. The helping professions make the world a better place for us to live in, even though they do not necessarily bear directly on the well being of any individual other than the recipients of care. This resolves the paradox of utilitarian care.

From Ends to Causes (and Back Again) by Metaphor: The Paradox of Natural Selection

NASA Astrophysics Data System (ADS)

Blancke, Stefaan; Schellens, Tammy; Soetaert, Ronald; Van Keer, Hilde; Braeckman, Johan

2014-04-01

Natural selection is one of the most famous metaphors in the history of science. Charles Darwin used the metaphor and the underlying analogy to frame his ideas about evolution and its main driving mechanism into a full-fledged theory. Because the metaphor turned out to be such a powerful epistemic tool, Darwin naturally assumed that he could also employ it as an educational tool to inform his contemporaries about his findings. Moreover, by using the metaphor Darwin was able to bring his theory in accordance with both the dominant philosophy of science in his time and the respected tradition of natural theology. However, as he introduced his theory of evolution by natural selection in On the origin of species in 1859, the metaphor also turned out to have a serious downside. Because of its intentional overtones, his contemporaries systematically misunderstood his metaphor not as a natural mechanism causing evolution to occur but as an agent who works towards particular ends. The difference in success between natural selection as an epistemic tool and its failure as an educational tool is labelled as a paradox. We explain the paradox from a cognitive perspective and discuss the implications for teaching evolution.

A dynamic Thurstonian item response theory of motive expression in the picture story exercise: solving the internal consistency paradox of the PSE.

PubMed

Lang, Jonas W B

2014-07-01

The measurement of implicit or unconscious motives using the picture story exercise (PSE) has long been a target of debate in the psychological literature. Most debates have centered on the apparent paradox that PSE measures of implicit motives typically show low internal consistency reliability on common indices like Cronbach's alpha but nevertheless predict behavioral outcomes. I describe a dynamic Thurstonian item response theory (IRT) model that builds on dynamic system theories of motivation, theorizing on the PSE response process, and recent advancements in Thurstonian IRT modeling of choice data. To assess the models' capability to explain the internal consistency paradox, I first fitted the model to archival data (Gurin, Veroff, & Feld, 1957) and then simulated data based on bias-corrected model estimates from the real data. Simulation results revealed that the average squared correlation reliability for the motives in the Thurstonian IRT model was .74 and that Cronbach's alpha values were similar to the real data (<.35). These findings suggest that PSE motive measures have long been reliable and increase the scientific value of extant evidence from motivational research using PSE motive measures. (c) 2014 APA, all rights reserved.

Benevolent Paradox: Integrating Community-Based Empowerment and Transdisciplinary Research Approaches into Traditional Frameworks to Increase Funding and Long-Term Sustainability of Chicano-Community Research Programs

ERIC Educational Resources Information Center

de la Torre, Adela

2014-01-01

Niños Sanos, Familia Sana (NSFS) is a 5-year multi-intervention study aimed at preventing childhood obesity among Mexican-origin children in rural California. Using a transdisciplinary approach and community-based participatory research (CBPR) methodology, NSFS's development included a diversely trained team working in collaboration with community…

Class, Gender, (Hetero)Sexuality and Schooling: Paradoxes within Working-Class Girls' Engagement with Education and Post-16 Aspirations

ERIC Educational Resources Information Center

Archer, Louise; Halsall, Anna; Hollingworth, Sumi

2007-01-01

This paper discusses the ways in which inner-city, ethnically diverse, working-class girls' constructions of hetero-femininities mediate and shape their dis/engagement with education and schooling. Drawing on data from a study conducted with 89 urban, working-class young people in London, attention is drawn to three main ways through which young…

Are Quantum Models for Order Effects Quantum?

NASA Astrophysics Data System (ADS)

Moreira, Catarina; Wichert, Andreas

2017-12-01

The application of principles of Quantum Mechanics in areas outside of physics has been getting increasing attention in the scientific community in an emergent disciplined called Quantum Cognition. These principles have been applied to explain paradoxical situations that cannot be easily explained through classical theory. In quantum probability, events are characterised by a superposition state, which is represented by a state vector in a N-dimensional vector space. The probability of an event is given by the squared magnitude of the projection of this superposition state into the desired subspace. This geometric approach is very useful to explain paradoxical findings that involve order effects, but do we really need quantum principles for models that only involve projections? This work has two main goals. First, it is still not clear in the literature if a quantum projection model has any advantage towards a classical projection. We compared both models and concluded that the Quantum Projection model achieves the same results as its classical counterpart, because the quantum interference effects play no role in the computation of the probabilities. Second, it intends to propose an alternative relativistic interpretation for rotation parameters that are involved in both classical and quantum models. In the end, instead of interpreting these parameters as a similarity measure between questions, we propose that they emerge due to the lack of knowledge concerned with a personal basis state and also due to uncertainties towards the state of world and towards the context of the questions.

The Paradox of Higher Vocational Education: The Teaching Assistant Game, the Pursuit of Capital and the Self

ERIC Educational Resources Information Center

Smith, Paul H.

2018-01-01

This article discusses the reasons offered by one group of paraprofessionals to explain their decision to study for a work-related higher education programme. It reports on an ethnographically inspired piece of research that aimed to capture the initial motives that a group of teaching assistants had for studying for a Foundation degree at a…

Killing the Mockingbird: Systems Failure and a Radical Hope for Re-Grounding Responsibility and Access to Health Care in a Mallee Town Community

ERIC Educational Resources Information Center

Coldwell, Ian

2010-01-01

The plight of Aboriginal health and the question of Aboriginal health care in a remote rural community came into focus when I realised that "the system" was peppered with in-built racist beliefs and values that discriminate against and disadvantage minority groups. Cyborg theory assists the difficulties of explaining the paradoxes that…

Spoiling Childhood: How Well-Meaning Parents Are Giving Children Too Much-But Not What They Need.

ERIC Educational Resources Information Center

Ehrensaft, Diane

Parents today are tagged as a generation preoccupied with work and themselves but at the same time overly focused on their children. This book attempts to explain this paradox. It explores the ways in which social, cultural, and psychological changes have come together with a new definition of the child to create a situation in which parenthood…

Cancer, Warts, or Asymptomatic Infections: Clinical Presentation Matches Codon Usage Preferences in Human Papillomaviruses

PubMed Central

Félez-Sánchez, Marta; Trösemeier, Jan-Hendrik; Bedhomme, Stéphanie; González-Bravo, Maria Isabel; Kamp, Christel; Bravo, Ignacio G.

2015-01-01

Viruses rely completely on the hosts’ machinery for translation of viral transcripts. However, for most viruses infecting humans, codon usage preferences (CUPrefs) do not match those of the host. Human papillomaviruses (HPVs) are a showcase to tackle this paradox: they present a large genotypic diversity and a broad range of phenotypic presentations, from asymptomatic infections to productive lesions and cancer. By applying phylogenetic inference and dimensionality reduction methods, we demonstrate first that genes in HPVs are poorly adapted to the average human CUPrefs, the only exception being capsid genes in viruses causing productive lesions. Phylogenetic relationships between HPVs explained only a small proportion of CUPrefs variation. Instead, the most important explanatory factor for viral CUPrefs was infection phenotype, as orthologous genes in viruses with similar clinical presentation displayed similar CUPrefs. Moreover, viral genes with similar spatiotemporal expression patterns also showed similar CUPrefs. Our results suggest that CUPrefs in HPVs reflect either variations in the mutation bias or differential selection pressures depending on the clinical presentation and expression timing. We propose that poor viral CUPrefs may be central to a trade-off between strong viral gene expression and the potential for eliciting protective immune response. PMID:26139833

In situ relationships between microbiota and potential pathobiota in Arabidopsis thaliana.

PubMed

Bartoli, Claudia; Frachon, Léa; Barret, Matthieu; Rigal, Mylène; Huard-Chauveau, Carine; Mayjonade, Baptiste; Zanchetta, Catherine; Bouchez, Olivier; Roby, Dominique; Carrère, Sébastien; Roux, Fabrice

2018-05-30

A current challenge in microbial pathogenesis is to identify biological control agents that may prevent and/or limit host invasion by microbial pathogens. In natura, hosts are often infected by multiple pathogens. However, most of the current studies have been performed under laboratory controlled conditions and by taking into account the interaction between a single commensal species and a single pathogenic species. The next step is therefore to explore the relationships between host-microbial communities (microbiota) and microbial members with potential pathogenic behavior (pathobiota) in a realistic ecological context. In the present study, we investigated such relationships within root-associated and leaf-associated bacterial communities of 163 ecologically contrasted Arabidopsis thaliana populations sampled across two seasons in southwest of France. In agreement with the theory of the invasion paradox, we observed a significant humped-back relationship between microbiota and pathobiota α-diversity that was robust between both seasons and plant organs. In most populations, we also observed a strong dynamics of microbiota composition between seasons. Accordingly, the potential pathobiota composition was explained by combinations of season-specific microbiota operational taxonomic units. This result suggests that the potential biomarkers controlling pathogen's invasion are highly dynamic.

Regional health inequalities: changes observed in Brazil from 2000-2016.

PubMed

Albuquerque, Mariana Vercesi de; Viana, Ana Luiza d'Ávila; Lima, Luciana Dias de; Ferreira, Maria Paula; Fusaro, Edgard Rodrigues; Iozzi, Fabíola Lana

2017-04-01

Advances in reducing poverty and inequalities in the 2000s had a paradoxical effect in Brazil. This article examines how socioeconomic transformations, and the complexity of health services, are expressed in the regions established for planning purposes and the inter-governmental management of the Brazilian Unified Health System. An effort was made to identify and explain differences in the compositions of the 438 existing health regions and their spatial distribution by comparing situations observed in 2016 with those in 2000. Factor analysis and grouping techniques were used to construct a typology in the two years of the series, which was based on a diverse set of secondary data sources. It was found that there was an evolution in terms of income levels and service provision within the health regions, with a significant improvement in the socioeconomic conditions of the population. These results suggest that there was a positive impact from the combination of strategies related to social, economic and regional policies for the promotion of development, which generated more widespread well-being within the affected areas. However, limitations remain regarding the policies implemented for the universalization of the health system.

The paradox of control: An ethnographic analysis of opiate maintenance treatment in a Norwegian prison.

PubMed

Mjåland, Kristian

2015-08-01

Opiate maintenance treatment (OMT) is increasingly being offered in prisons throughout Europe. The benefits of OMT in prison have been found to be similar to those produced by OMT in community settings. However, prison-based OMT has been a controversial issue because of fear of the diversion of OMT medications and the development of black markets for prescription drugs such as buprenorphine and methadone. Prison-based OMT thus involves a delicate balance between the considerations of control and treatment. This article reports on an ethnographic study of a prison-based OMT programme in a closed Norwegian prison. The data include field notes from eight months of participant observation in the prison as well as qualitative interviews with 23 prisoners and 12 prison staff. Midway through the fieldwork, the prison authorities established a separate unit for OMT-enrolled prisoners to reduce the widespread diversion of buprenorphine. This "natural experiment" is explored in the analysis. The prison-based OMT programme was characterised by strict and repressive control to prevent the diversion of buprenorphine, and the control became even stricter after the establishment of the OMT unit. However, the diversion of buprenorphine increased rather than decreased after the establishment of the OMT unit. To understand this "paradox of control", the article engages with theories of legitimacy, power and resistance. The excessive and repressive control was perceived as illegitimate and unfair by the majority of study participants. In various ways, many prisoners protested, confronted and subverted the OMT programme. The increase in buprenorphine diversion is interpreted as a form of collective resistance towards the perceived unfairness of the OMT programme. The article demonstrates that an unbalanced and control-dominated approach to prison-based OMT may have the opposite effect of what is intended. Copyright © 2015 The Author. Published by Elsevier B.V. All rights reserved.

Teichmuller Space Resolution of the EPR Paradox

NASA Astrophysics Data System (ADS)

Winterberg, Friedwardt

2013-04-01

The mystery of Newton's action-at-a-distance law of gravity was resolved by Einstein with Riemann's non-Euclidean geometry, which permitted the explanation of the departure from Newton's law for the motion of Mercury. It is here proposed that the similarly mysterious non-local EPR-type quantum correlations may be explained by a Teichmuller space geometry below the Planck length, for which an experiment for its verification is proposed.

Unthermal Hawking Radiation from a General Stationary Black Hole

NASA Astrophysics Data System (ADS)

Zhang, Yong-Ping; Dai, Qian; Liu, Wen-Biao

2008-02-01

Using Damour Ruffini's method, Hawking radiation from a general stationary black hole is investigated again deeply. Considering the back reaction of the particle to the space-time and energy conservation, we find that the radiation is not exactly thermal and can take out information from the black hole. This can be used to explain the information loss paradox, and the result is consistent with the works finished before.

Hawking Radiation from a Spherically Symmetric Static Black Hole

NASA Astrophysics Data System (ADS)

Dai, Qian; Liu, Wenbiao

2007-08-01

The massive particles’ Hawking radiation from a spherically symmetric static black hole is investigated with Parikh-Wilczek method, Hamilton Jacobi method and Damour Ruffini’s method. When energy conservation is considered, the same result can be concluded that the radiation spectrum is not precisely thermal. The corrected spectrum is consistent to the underlying unitary quantum theory, which can be used to explain the information loss paradox possibly.

A Solution to the C-Value Paradox and the Function of Junk DNA: The Genome Balance Hypothesis.

PubMed

Freeling, Michael; Xu, Jie; Woodhouse, Margaret; Lisch, Damon

2015-06-01

The Genome Balance Hypothesis originated from a recent study that provided a mechanism for the phenomenon of genome dominance in ancient polyploids: unique 24nt RNA coverage near genes is greater in genes on the recessive subgenome irrespective of differences in gene expression. 24nt RNAs target transposons. Transposon position effects are now hypothesized to balance the expression of networked genes and provide spring-like tension between pericentromeric heterochromatin and microtubules. The balance (coordination) of gene expression and centromere movement is under selection. Our hypothesis states that this balance can be maintained by many or few transposons about equally well. We explain known balanced distributions of junk DNA within genomes and between subgenomes in allopolyploids (and our hypothesis passes "the onion test" for any so-called solution to the C-value paradox). Importantly, when the allotetraploid maize chromosomes delete redundant genes, their nearby transposons are also lost; this result is explained if transposons near genes function. The Genome Balance Hypothesis is hypothetical because the position effect mechanisms implicated are not proved to apply to all junk DNA, and the continuous nature of the centromeric and gene position effects have not yet been studied as a single phenomenon. Copyright © 2015 The Author. Published by Elsevier Inc. All rights reserved.

Vers une approche globale de l'évolution des HominidésTowards an all-round approach to Hominid evolution

NASA Astrophysics Data System (ADS)

Chaline, Jean

1998-03-01

Two models of diversification of the common ancestor of gorillas, chimpanzees and men can be proposed on the basis of the distribution of chromosomal rearrangements in extant species and reconsideration of the role played by climate. The small genetic divergence between chimpanzees and humans is greatly amplified at the morphological level, thus constituting the 'human paradox'. This paradox is resolved by the economical and flexible evolutionary mechanism of mutations in regulator genes and the heterochronies they control, which are the true internal clocks of evolution. Changes in cranial morphology are quantified and used to analyse and explain the steps in the transition from great ape to human morphology. By comparison at the various stages of development, it is suggested that from great apes to modern man numerous heterochronies have occured during ontogeny (hypermorphosis, hypomorphosis and post-displacements).

Dissipative inertial transport patterns near coherent Lagrangian eddies in the ocean.

PubMed

Beron-Vera, Francisco J; Olascoaga, María J; Haller, George; Farazmand, Mohammad; Triñanes, Joaquín; Wang, Yan

2015-08-01

Recent developments in dynamical systems theory have revealed long-lived and coherent Lagrangian (i.e., material) eddies in incompressible, satellite-derived surface ocean velocity fields. Paradoxically, observed drifting buoys and floating matter tend to create dissipative-looking patterns near oceanic eddies, which appear to be inconsistent with the conservative fluid particle patterns created by coherent Lagrangian eddies. Here, we show that inclusion of inertial effects (i.e., those produced by the buoyancy and size finiteness of an object) in a rotating two-dimensional incompressible flow context resolves this paradox. Specifically, we obtain that anticyclonic coherent Lagrangian eddies attract (repel) negatively (positively) buoyant finite-size particles, while cyclonic coherent Lagrangian eddies attract (repel) positively (negatively) buoyant finite-size particles. We show how these results explain dissipative-looking satellite-tracked surface drifter and subsurface float trajectories, as well as satellite-derived Sargassum distributions.

A New Clinical Sign of Lumbrical Plus Finger.

PubMed

Schuind, Frédéric A; Moungondo, Fabian; Van Wetter, Pierre

2018-06-01

Paradoxical finger extension is the classical clinical presentation of the lumbrical plus syndrome. We report a new additional sign, increased metacarpophalangeal flexion of the involved finger when the patient tries to make a fist. Three cases of lumbrical tightness are discussed, illustrating this new sign in 3 different clinical settings. The new sign was present in all 3 cases. Lumbrical tenotomy corrected the paradoxical interphalangeal extension and partly the increased metacarpophalangeal flexion. The lumbrical tendon has a relatively high moment arm relative to the metacarpophalangeal joint, which could explain the basis of this clinical sign. This new physical examination sign may help in diagnosing the lumbrical plus syndrome, a subtle complication of flexor digitorum profundus lesions that is not easily diagnosed but which is easily addressed. Copyright © 2018 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Principles, problems, and paradoxes of cosmogony

NASA Astrophysics Data System (ADS)

Treder, H.-J.

The historical development of scientific theories of cosmogony since Newton and Kant is traced, with emphases on the inherent problems and paradoxes and on the evolution of the solar system. The basic conflict between the Newtonian concept of ahistorical physical processes in reversible time and the thermodynamic principle of irreversible entropy increase is seen as only partially resolved by the modern view that microscale events are reversible while macroscale events are not. It is shown that the theory of an adiabatic isentropic expansion of the universe cannot yet explain the genesis of galaxies of 10 billion stars. Kant's cosmogony of the solar system by condensation from a gas cloud is considered qualitatively valid; quantitative corrections, especially for the planets and their satellites, are discussed and related to the hypotheses of La Place. The observations of Barnard's star by van de Kamp, indicating the existence of Jupiter-like planets in almost circular orbits around it, are considered.

Perceptual belongingness determines the direction of lightness induction depending on grouping stability and intentionality.

PubMed

Murgia, Mauro; Prpic, Valter; Santoro, Ilaria; Sors, Fabrizio; Agostini, Tiziano; Galmonte, Alessandra

2016-09-01

Contrast and assimilation are two opposite perceptual phenomena deriving from the relationships among perceptual elements in a visual field. In contrast, perceptual differences are enhanced; while, in assimilation, they are decreased. Indeed, if contrast or assimilation occurs depends on various factors. Interestingly, Gestalt scientists explained both phenomena as the result of perceptual belongingness, giving rise to an intriguing paradox. Benary suggested that belongingness determines contrast; conversely, Fuchs suggested that it determines assimilation. This paradox can be related both to the grouping stability (stable/multi-stable) and to the grouping intentionality (intentional/non-intentional). In the present work we ran four experiments to test whether the contrast/assimilation outcomes depend on the above-mentioned variables. We found that, intentionality and multi-stability elicit assimilation; while, non-intentionality and stability elicit contrast. Copyright © 2016 Elsevier Ltd. All rights reserved.

The reliability paradox of the Parent-Child Conflict Tactics Corporal Punishment Subscale.

PubMed

Lorber, Michael F; Slep, Amy M Smith

2018-02-01

In the present investigation we consider and explain an apparent paradox in the measurement of corporal punishment with the Parent-Child Conflict Tactics Scale (CTS-PC): How can it have poor internal consistency and still be reliable? The CTS-PC was administered to a community sample of 453 opposite sex couples who were parents of 3- to 7-year-old children. Internal consistency was marginal, yet item response theory analyses revealed that reliability rose sharply with increasing corporal punishment, exceeding .80 in the upper ranges of the construct. The results suggest that the CTS-PC Corporal Punishment subscale reliably discriminates among parents who report average to high corporal punishment (64% of mothers and 56% of fathers in the present sample), despite low overall internal consistency. These results have straightforward implications for the use and reporting of the scale. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

The Faint Young Sun Paradox in the Context of Modern Cosmology

NASA Astrophysics Data System (ADS)

Dumin, Yu. V.

2015-09-01

The Faint Young Sun Paradox comes from the fact that solar luminosity (2-4)x10^9 years ago was insufficient to support the Earth's temperature necessary for the efficient development of geological and biological evolution (particularly, for the existence of considerable volumes of liquid water). It remains unclear by now if the so-called greenhouse effect on the Earth can resolve this problem. An interesting alternative explanation was put forward recently by M.Krizek (New Astron. 2012, 17, 1), who suggested that planetary orbits expand with time due to the local Hubble effect, caused by the uniformly-distributed Dark Energy. Then, under a reasonable value of the local Hubble constant, it is easy to explain why the Earth was receiving an approximately constant amount of solar irradiation for a long period in the past and will continue to do so for a quite long time in future.

Characterization of a gel in the cell wall to elucidate the paradoxical shrinkage of tension wood.

PubMed

Clair, Bruno; Gril, Joseph; Di Renzo, Francesco; Yamamoto, Hiroyuki; Quignard, Françoise

2008-02-01

Wood behavior is characterized by high sensibility to humidity and strongly anisotropic properties. The drying shrinkage along the fibers, usually small due to the reinforcing action of cellulosic microfibrils, is surprisingly high in the so-called tension wood, produced by trees to respond to strong reorientation requirements. In this study, nitrogen adsorption-desorption isotherms of supercritically dried tension wood and normal wood show that the tension wood cell wall has a gel-like structure characterized by a pore surface more than 30 times higher than that in normal wood. Syneresis of the tension wood gel explains its paradoxical drying shrinkage. This result could help to reduce technological problems during drying. Potential applications in biomechanics and biomimetics are worth investigating, considering that, in living trees, tension wood produces tensile growth stresses 10 times higher than that of normal wood.

Flash-lag effect: complicating motion extrapolation of the moving reference-stimulus paradoxically augments the effect.

PubMed

Bachmann, Talis; Murd, Carolina; Põder, Endel

2012-09-01

One fundamental property of the perceptual and cognitive systems is their capacity for prediction in the dynamic environment; the flash-lag effect has been considered as a particularly suggestive example of this capacity (Nijhawan in nature 370:256-257, 1994, Behav brain sci 31:179-239, 2008). Thus, because of involvement of the mechanisms of extrapolation and visual prediction, the moving object is perceived ahead of the simultaneously flashed static object objectively aligned with the moving one. In the present study we introduce a new method and report experimental results inconsistent with at least some versions of the prediction/extrapolation theory. We show that a stimulus moving in the opposite direction to the reference stimulus by approaching it before the flash does not diminish the flash-lag effect, but rather augments it. In addition, alternative theories (in)capable of explaining this paradoxical result are discussed.

Aging and fear of crime: an experimental approach to an apparent paradox.

PubMed

Ziegler, Raphael; Mitchell, David B

2003-01-01

Many fear of crime studies have revealed an interesting paradox: Although older adults are less likely to be victims, they report a higher fear of crime than younger adults. In this study, we experimentally manipulated vicarious exposure to crime. Younger (ages 18-29) and older adults (ages 61-78) were randomly assigned to view either a vivid video reenactment of a violent crime or a crime report newscast. Subjects in the violent video condition demonstrated significantly higher fear than did control group participants, but this effect was reliable only for younger adults. The older adults appeared to be unfazed by the violent video, and reported significantly less fear than the younger group. This could not be explained away on the basis of age group differences in neighborhood crime rates, victimization experience, or media exposure. Thus, when greater fear of crime is found in older adults, "old age" per se is not the cause.

Thinspiration: Self-Improvement Versus Self-Evaluation Social Comparisons with Thin-Ideal Media Portrayals.

PubMed

Knobloch-Westerwick, Silvia

2015-01-01

Much research has demonstrated negative impacts of idealized-body imagery exposure on body satisfaction. Yet, paradoxically, media with such imagery attract mass audiences. Few studies showed women's body satisfaction increased due to thin-ideal exposure. The kind of social comparison women engage in (self-evaluation vs. self-improvement) may explain these inconsistent findings and the paradoxical attraction to thin-ideal messages. Across 5 days, thin-ideal messages were presented to 51 women; self-evaluation and self-improvement social comparisons as well as body satisfaction were measured each day. A linear positive change in body satisfaction emerged. Greater self-improvement social comparisons increased this change, whereas greater self-evaluation social comparisons reduced it. Extent of both social comparison types changed during the prolonged exposure. A greater tendency to compare one's body with others' improved body satisfaction through self-improvement social comparisons and fostered weight-loss behaviors through self-evaluation social comparisons.

[Atherosclerosis, oxidative stress and physical activity. Review].

PubMed

Calderón, Juan Camilo; Fernández, Ana Zita; María de Jesús, Alina Isabel

2008-09-01

Atherosclerosis and related diseases have emerged as the leading cause of morbidity and mortality in the western world and, therefore, as a problem of public health. Free radicals and reactive oxygen species have been suggested to be part of the pathophysiology of these diseases. It is well known that physical activity plays an important role as a public health measure by reducing the risk of developing atherosclerosis-related cardiovascular events in the general population. It is also known that physical activity increases in some tissues, the reactive oxygen species production. In this review the atherosclerosis-oxidative stress-physical activity relationship is focused on the apparent paradox by which physical activity reduces atherosclerosis and cardiovascular risk in parallel with the activation of an apparently damaging mechanism which is an increased oxidative stress. A hypothesis including the experimental and clinical evidence is presented to explain the aforementioned paradox.

Dynamic breaking of a single gold bond

NASA Astrophysics Data System (ADS)

Pobelov, Ilya V.; Lauritzen, Kasper Primdal; Yoshida, Koji; Jensen, Anders; Mészáros, Gábor; Jacobsen, Karsten W.; Strange, Mikkel; Wandlowski, Thomas; Solomon, Gemma C.

2017-07-01

While one might assume that the force to break a chemical bond gives a measure of the bond strength, this intuition is misleading. If the force is loaded slowly, thermal fluctuations may break the bond before it is maximally stretched, and the breaking force will be less than the bond can sustain. Conversely, if the force is loaded rapidly it is more likely that the maximum breaking force is measured. Paradoxically, no clear differences in breaking force were observed in experiments on gold nanowires, despite being conducted under very different conditions. Here we explore the breaking behaviour of a single Au-Au bond and show that the breaking force is dependent on the loading rate. We probe the temperature and structural dependencies of breaking and suggest that the paradox can be explained by fast breaking of atomic wires and slow breaking of point contacts giving very similar breaking forces.

The intelligence paradox; will ET get the metabolic syndrome? Lessons from and for Earth.

PubMed

Nunn, Alistair V W; Guy, Geoffrey W; Bell, Jimmy D

2014-01-01

Mankind is facing an unprecedented health challenge in the current pandemic of obesity and diabetes. We propose that this is the inevitable (and predictable) consequence of the evolution of intelligence, which itself could be an expression of life being an information system driven by entropy. Because of its ability to make life more adaptable and robust, intelligence evolved as an efficient adaptive response to the stresses arising from an ever-changing environment. These adaptive responses are encapsulated by the epiphenomena of "hormesis", a phenomenon we believe to be central to the evolution of intelligence and essential for the maintenance of optimal physiological function and health. Thus, as intelligence evolved, it would eventually reach a cognitive level with the ability to control its environment through technology and have the ability remove all stressors. In effect, it would act to remove the very hormetic factors that had driven its evolution. Mankind may have reached this point, creating an environmental utopia that has reduced the very stimuli necessary for optimal health and the evolution of intelligence - "the intelligence paradox". One of the hallmarks of this paradox is of course the rising incidence in obesity, diabetes and the metabolic syndrome. This leads to the conclusion that wherever life evolves, here on earth or in another part of the galaxy, the "intelligence paradox" would be the inevitable side-effect of the evolution of intelligence. ET may not need to just "phone home" but may also need to "phone the local gym". This suggests another possible reason to explain Fermi's paradox; Enrico Fermi, the famous physicist, suggested in the 1950s that if extra-terrestrial intelligence was so prevalent, which was a common belief at the time, then where was it? Our suggestion is that if advanced life has got going elsewhere in our galaxy, it can't afford to explore the galaxy because it has to pay its healthcare costs.

Obesity paradox and mortality in adults with and without incident type 2 diabetes: a matched population-level cohort study

PubMed Central

Badrick, Ellena; Sperrin, Matthew; Buchan, Iain E

2017-01-01

Objective Among adults with type 2 diabetes (T2D), several (but not all) studies show that being overweight (body mass index (BMI): 25.0–29.9 kg/m2) or obese I (BMI: 30.0–34.9 kg/m2) near the time of diagnosis, is unexpectedly associated with reduced all-cause mortality compared with normal weight—the obesity paradox. We addressed whether this observation is causal (eg, a true protective effect); due to confounding (including effect modification); or due to selection (‘collider’) bias. Research design and methods We performed a matched population-level cohort study using primary care records from Salford, UK (1995–2012) in 10 464 patients with incident T2D paired (1:3) with 31 020 individuals who never developed T2D. We estimated HRs for associations of BMI with all-cause mortality using Cox models, stratified by smoking status. Results Median follow-up was 8.7 years. For never smokers, the hazard of all-cause mortality increased from 25 kg/m2, in a linear manner, with increasing BMI in the T2D cohort (HR per 5 kg/m2: 1.23, ptrend<0.001) and in the non-diabetes cohort (HR per 5 kg/m2: 1.34, ptrend<0.001). In contrast, among ever smokers, BMI-mortality relationships were U-shaped in the T2D and non-diabetes cohorts. Evidence of the obesity paradox in ever smokers, with and without T2D, argued against a selection bias, but supported a contribution of effect modification by smoking (pinteraction=0.009). Results were stable to various sensitivity analyses. Conclusions In this cohort, the obesity paradox is mainly explained by smoking as an effect modifier. These findings indicate that the obesity paradox does not challenge standard weight management recommendations among T2D patients. PMID:28321314

Condition-dependence, genotype-by-environment interactions and the lek paradox.

PubMed

Kokko, Hanna; Heubel, Katja

2008-09-01

The lek paradox states that maintaining genetic variation necessary for 'indirect benefit' models of female choice is difficult, and two interrelated solutions have been proposed. 'Genic capture' assumes condition-dependence of sexual traits, while genotype-by-environment interactions (GEIs) offer an additional way to maintain diversity. However, condition-dependence, particularly with GEIs, implies that environmental variation can blur the relationship between male displays and offspring fitness. These issues have been treated separately in the past. Here we combine them in a population genetic model, and show that predictions change not only in magnitude but also in direction when the timing of dispersal between environments relative to the life cycle is changed. GEIs can dramatically improve the evolution of costly female preferences, but also hamper it if much dispersal occurs between the life history stage where condition is determined and mating. This situation also arises if selection or mutation rates are too high. In general, our results highlight that when evaluating any mechanism promoted as a potential resolution of the lek paradox, it is not sufficient to focus on its effects on genetic variation. It also has to be assessed to what extent the proposed mechanism blurs the association between male attractiveness and offspring fitness; the net balance of these two effects can be positive or negative, and often strongly context-dependent.

Condition-dependence, genotype-by-environment interactions and the lek paradox.

PubMed

Kokko, Hanna; Heubel, Katja

2008-02-01

The lek paradox states that maintaining genetic variation necessary for 'indirect benefit' models of female choice is difficult, and two interrelated solutions have been proposed. 'Genic capture' assumes condition-dependence of sexual traits, while genotype-by-environment interactions (GEIs) offer an additional way to maintain diversity. However, condition-dependence, particularly with GEIs, implies that environmental variation can blur the relationship between male displays and offspring fitness. These issues have been treated separately in the past. Here we combine them in a population genetic model, and show that predictions change not only in magnitude but also in direction when the timing of dispersal between environments relative to the life cycle is changed. GEIs can dramatically improve the evolution of costly female preferences, but also hamper it if much dispersal occurs between the life history stage where condition is determined and mating. This situation also arises if selection or mutation rates are too high. In general, our results highlight that when evaluating any mechanism promoted as a potential resolution of the lek paradox, it is not sufficient to focus on its effects on genetic variation. It also has to be assessed to what extent the proposed mechanism blurs the association between male attractiveness and offspring fitness; the net balance of these two effects can be positive or negative, and often strongly context-dependent.

Barcoding against a paradox? Combined molecular species delineations reveal multiple cryptic lineages in elusive meiofaunal sea slugs

PubMed Central

2012-01-01

Background Many marine meiofaunal species are reported to have wide distributions, which creates a paradox considering their hypothesized low dispersal abilities. Correlated with this paradox is an especially high taxonomic deficit for meiofauna, partly related to a lower taxonomic effort and partly to a high number of putative cryptic species. Molecular-based species delineation and barcoding approaches have been advocated for meiofaunal biodiversity assessments to speed up description processes and uncover cryptic lineages. However, these approaches show sensitivity to sampling coverage (taxonomic and geographic) and the success rate has never been explored on mesopsammic Mollusca. Results We collected the meiofaunal sea-slug Pontohedyle (Acochlidia, Heterobranchia) from 28 localities worldwide. With a traditional morphological approach, all specimens fall into two morphospecies. However, with a multi-marker genetic approach, we reveal multiple lineages that are reciprocally monophyletic on single and concatenated gene trees in phylogenetic analyses. These lineages are largely concordant with geographical and oceanographic parameters, leading to our primary species hypothesis (PSH). In parallel, we apply four independent methods of molecular based species delineation: General Mixed Yule Coalescent model (GMYC), statistical parsimony, Bayesian Species Delineation (BPP) and Automatic Barcode Gap Discovery (ABGD). The secondary species hypothesis (SSH) is gained by relying only on uncontradicted results of the different approaches (‘minimum consensus approach’), resulting in the discovery of a radiation of (at least) 12 mainly cryptic species, 9 of them new to science, some sympatric and some allopatric with respect to ocean boundaries. However, the meiofaunal paradox still persists in some Pontohedyle species identified here with wide coastal and trans-archipelago distributions. Conclusions Our study confirms extensive, morphologically cryptic diversity among meiofauna and accentuates the taxonomic deficit that characterizes meiofauna research. We observe for Pontohedyle slugs a high degree of morphological simplicity and uniformity, which we expect might be a general rule for meiofauna. To tackle cryptic diversity in little explored and hard-to-sample invertebrate taxa, at present, a combined approach seems most promising, such as multi-marker-barcoding (i.e., molecular systematics using mitochondrial and nuclear markers and the criterion of reciprocal monophyly) combined with a minimum consensus approach across independent methods of molecular species delineation to define candidate species. PMID:23244441

The multiple facets of Peto's paradox: a life-history model for the evolution of cancer suppression

PubMed Central

Brown, Joel S.; Cunningham, Jessica J.; Gatenby, Robert A.

2015-01-01

Large animals should have higher lifetime probabilities of cancer than small animals because each cell division carries an attendant risk of mutating towards a tumour lineage. However, this is not observed—a (Peto's) paradox that suggests large and/or long-lived species have evolved effective cancer suppression mechanisms. Using the Euler–Lotka population model, we demonstrate the evolutionary value of cancer suppression as determined by the ‘cost’ (decreased fecundity) of suppression verses the ‘cost’ of cancer (reduced survivorship). Body size per se will not select for sufficient cancer suppression to explain the paradox. Rather, cancer suppression should be most extreme when the probability of non-cancer death decreases with age (e.g. alligators), maturation is delayed, fecundity rates are low and fecundity increases with age. Thus, the value of cancer suppression is predicted to be lowest in the vole (short lifespan, high fecundity) and highest in the naked mole rat (long lived with late female sexual maturity). The life history of pre-industrial humans likely selected for quite low levels of cancer suppression. In modern humans that live much longer, this level results in unusually high lifetime cancer risks. The model predicts a lifetime risk of 49% compared with the current empirical value of 43%. PMID:26056365

The intermediate disturbance hypothesis applies to tropical forests, but disturbance contributes little to tree diversity.

PubMed

Bongers, Frans; Poorter, Lourens; Hawthorne, William D; Sheil, Douglas

2009-08-01

The intermediate disturbance hypothesis (IDH) predicts local species diversity to be maximal at an intermediate level of disturbance. Developed to explain species maintenance and diversity patterns in species-rich ecosystems such as tropical forests, tests of IDH in tropical forest remain scarce, small-scale and contentious. We use an unprecedented large-scale dataset (2504 one-hectare plots and 331,567 trees) to examine whether IDH explains tree diversity variation within wet, moist and dry tropical forests, and we analyse the underlying mechanism by determining responses within functional species groups. We find that disturbance explains more variation in diversity of dry than wet tropical forests. Pioneer species numbers increase with disturbance, shade-tolerant species decrease and intermediate species are indifferent. While diversity indeed peaks at intermediate disturbance levels little variation is explained outside dry forests, and disturbance is less important for species richness patterns in wet tropical rain forests than previously thought.

Sexual Networks of Racially Diverse Young MSM Differ in Racial Homophily But Not Concurrency.

PubMed

Janulis, Patrick; Phillips, Gregory; Birkett, Michelle; Mustanski, Brian

2018-04-15

Substantial racial disparities exist in HIV infection among young men who have sex with men (YMSM). However, evidence suggests black YMSM do not engage in greater levels of risk behavior. Sexual networks may help explain this paradox. This study used egocentric exponential random graph models to examine variation in concurrency (ie, 2 or more simultaneous partners) and homophily (ie, same race/ethnicity partners) across race/ethnicity groups in a diverse sample of YMSM. Data for this study come from a longitudinal cohort study of YMSM. Participants (n = 1012) provided data regarding their sexual contacts during the 6 months before their first study visit. A series of egocentric exponential random graph models examined how providing separate estimates for homophily and concurrency parameters across race/ethnicity improved the fit of these models. Networks were simulated using these parameters to examine how local network characteristics impact risk at the whole network level. Results indicated that homophily, but not concurrency, varied across race/ethnicity. Black participants witnessed significantly higher race/ethnicity homophily compared with white and Latino peers. Extrapolating from these models, black individuals were more likely to be in a connected component with an HIV-positive individual and closer to HIV-positive individuals. However, white individuals were more likely to be in large connected components. These findings suggest that high racial homophily combined with existing disparities in HIV help perpetuate the spread of HIV among black YMSM. Nonetheless, additional work is required to understand these disparities given that homophily alone cannot sustain them indefinitely.

Utopian Vision: A Grand Solution for a Scholarly Dilemma.

PubMed

Watts, Roderick J

2017-06-01

Reconciling the Zen-like paradox on the back of every red penny-"out of many, one"-is not for the faint of heart. It is a diversity motto, and a lofty desire that the United States claims to covet. But can its citizens, undocumented or otherwise, even agree on what it is? Is not the desire to maintain a strong sense of community in conflict with a Noah's Ark conception of diversity? Using my personal experience in an intentional community determined to foster racial integration, I explore the complicated possibility of having it both ways. To do so, however, we must construct a notion of community, diversity, and The Good Life that will make us believe and work for this synthesis. Our reactions to the word "utopia" offer a glimpse of the challenges ahead. © Society for Community Research and Action 2017.

The Paradox of German Foreign and Security Policy: With Respect to National Energy Security

DTIC Science & Technology

2009-05-21

analysis from an historical perspective and first published post- materialist theory. It builds on Maslow ‟s hierarchy of needs and seeks to explain how...and maintaining the data needed , and completing and reviewing this collection of information. Send comments regarding this burden estimate or any...policy. Being strategically prepared when market forces fail to balance contradictory interests becomes a necessity for many countries. Based on Germany

TeV-photon paradox and space with SU(2) fuzziness

NASA Astrophysics Data System (ADS)

Shariati, A.; Khorrami, M.; Fatollahi, A. H.

2008-02-01

The possibility is examined that a model based on space noncommutativity of linear type can explain why photons from distant sources with multi-TeV energies can reach the Earth. In particular within a model in which space coordinates satisfy the algebra of the SU(2) Lie group, it is shown that there is a possibility that the pair production through the reaction of CMB and energetic photons be forbidden kinematically.

Complex Teichmüller Space below the Planck Length for the Interpretation of Quantum Mechanics

NASA Astrophysics Data System (ADS)

Winterberg, Friedwardt

2014-03-01

As Newton's mysterious action at a distance law of gravity was explained as a Riemannian geometry by Einstein, it is proposed that the likewise mysterious non-local quantum mechanics is explained by the analytic continuation below the Planck length into a complex Teichmüller space. Newton's theory worked extremely well, as does quantum mechanics, but no satisfactory explanation has been given for quantum mechanics. In one space dimension, sufficient to explain the EPR paradox, the Teichmüller space is reduced to a space of complex Riemann surfaces. Einstein's curved space-time theory of gravity was confirmed by a tiny departure from Newton's theory in the motion of the planet Mercury, and an experiment is proposed to demonstrate the possible existence of a Teichmüller space below the Planck length.

Weight Loss, the Obesity Paradox, and the Risk of Death in Rheumatoid Arthritis

PubMed Central

Baker, Joshua F.; Billig, Erica; Michaud, Kaleb; Ibrahim, Said; Caplan, Liron; Cannon, Grant W.; Stokes, Andrew; Majithia, Vikas; Mikuls, Ted R.

2016-01-01

Objective In contrast to what is observed in the general population, a low body mass index (BMI) has been associated with accelerated mortality in patients with rheumatoid arthritis (RA). The aim of this study was to assess whether weight loss might explain these seemingly paradoxical observations. Methods Our study included patients identified from the Veterans Affairs (VA) RA Registry. Dates of death were abstracted from VA electronic medical records. The BMI at each study visit and the change from the previous visit were determined. The maximum BMI of each patient was also obtained from medical records. The annualized rate of BMI loss was determined from the slope of change (per year) in BMI over visits within the preceding 13 months. Cox multivariable proportional hazards models were used to assess associations between BMI measures and mortality. Results In a sample of 1,674 patients, 312 deaths occurred over 9,183 person-years. A loss in BMI of ≥1 kg/m2 was associated with a greater risk of death, after adjustment for demographics, comorbidities, BMI, smoking, and RA therapies (hazard ratio [HR] 1.99, 95% confidence interval [95% CI] 1.53–2.59, P < 0.001). This association remained significant in a subsample analysis adjusting for C-reactive protein and physical function (HR 1.81, 95% CI 1.36–2.41, P < 0.001). Weight loss at an annualized rate of ≥3 kg/m2 was associated with the greatest risk of death (HR 2.49, 95% CI 1.73–3.57, P < 0.001). Low BMI (<20 kg/m2) in patients with a history of obesity (>30 kg/m2) was associated with the greatest risk (HR 8.52, 95% CI 4.10–17.71, P < 0.001). Conclusion Weight loss is a strong predictor of death in patients with RA. These observations may explain the observed obesity paradox and do not support a biologically protective role of obesity. PMID:25940140

The obesity paradox in men with coronary heart disease and heart failure: the role of muscle mass and leptin.

PubMed

Wannamethee, S Goya; Shaper, A Gerald; Whincup, Peter H; Lennon, Lucy; Papacosta, Olia; Sattar, Naveed

2014-01-15

We have investigated the role of muscle mass, natriuretic peptides and adipokines in explaining the obesity paradox. The obesity paradox relates to the association between obesity and increased survival in patients with coronary heart disease (CHD) or heart failure (HF). Prospective study of 4046 men aged 60-79 years followed up for a mean period of 11 years, during which 1340 deaths occurred. The men were divided according to the presence of doctor diagnosed CHD and HF: (i) no CHD or HF ii), with CHD (no HF) and (iii) with HF. Overweight (BMI 25-9.9 kg/m(2)) and obesity (BMI ≥ 30 kg/m(2)) were associated with lower mortality risk compared to men with normal weight (BMI 18.5-24.9 kg/m(2)) in those with CHD [hazards ratio (HR) 0.71 (0.56,0.91) and 0.77 (0.57,1.04); p=0.04 for trend] and in those with HF [HR 0.57 (0.28,1.16) and 0.41 (0.16,1.09; p=0.04 for trend). Adjustment for muscle mass and NT-proBNP attenuated the inverse association in those with CHD (no HF) [HR 0.78 (0.61,1.01) and 0.96 (0.68,1.36) p=0.60 for trend) but made minor differences to those with HF [p=0.05]. Leptin related positively to mortality in men without HF but inversely to mortality in those with HF; adjustment for leptin abolished the BMI mortality association in men with HF [HR 0.82 (0.31,2.20) and 0.99 (0.27,3.71); p=0.98 for trend]. The lower mortality risk associated with excess weight in men with CHD without HF may be due to higher muscle mass. In men with HF, leptin (possibly reflecting cachexia) explain the inverse association. Copyright © 2013. Published by Elsevier Ireland Ltd.

Weight Loss, the Obesity Paradox, and the Risk of Death in Rheumatoid Arthritis.

PubMed

Baker, Joshua F; Billig, Erica; Michaud, Kaleb; Ibrahim, Said; Caplan, Liron; Cannon, Grant W; Stokes, Andrew; Majithia, Vikas; Mikuls, Ted R

2015-07-01

In contrast to what is observed in the general population, a low body mass index (BMI) has been associated with accelerated mortality in patients with rheumatoid arthritis (RA). The aim of this study was to assess whether weight loss might explain these seemingly paradoxical observations. Our study included patients identified from the Veterans Affairs (VA) RA Registry. Dates of death were abstracted from VA electronic medical records. The BMI at each study visit and the change from the previous visit were determined. The maximum BMI of each patient was also obtained from medical records. The annualized rate of BMI loss was determined from the slope of change (per year) in BMI over visits within the preceding 13 months. Cox multivariable proportional hazards models were used to assess associations between BMI measures and mortality. In a sample of 1,674 patients, 312 deaths occurred over 9,183 person-years. A loss in BMI of ≥1 kg/m(2) was associated with a greater risk of death, after adjustment for demographics, comorbidities, BMI, smoking, and RA therapies (hazard ratio [HR] 1.99, 95% confidence interval [95% CI] 1.53-2.59, P < 0.001). This association remained significant in a subsample analysis adjusting for C-reactive protein and physical function (HR 1.81, 95% CI 1.36-2.41, P < 0.001). Weight loss at an annualized rate of ≥3 kg/m(2) was associated with the greatest risk of death (HR 2.49, 95% CI 1.73-3.57, P < 0.001). Low BMI (<20 kg/m(2) ) in patients with a history of obesity (>30 kg/m(2) ) was associated with the greatest risk (HR 8.52, 95% CI 4.10-17.71, P < 0.001). Weight loss is a strong predictor of death in patients with RA. These observations may explain the observed obesity paradox and do not support a biologically protective role of obesity. © 2015, American College of Rheumatology.

Ancestral Rocky Mountian Tectonics: A Sedimentary Record of Ancestral Front Range and Uncompahgre Exhumation

NASA Astrophysics Data System (ADS)

Smith, T. M.; Saylor, J. E.; Lapen, T. J.

2015-12-01

The Ancestral Rocky Mountains (ARM) encompass multiple crustal provinces with characteristic crystallization ages across the central and western US. Two driving mechanisms have been proposed to explain ARM deformation. (1) Ouachita-Marathon collision SE of the ARM uplifts has been linked to an E-to-W sequence of uplift and is consistent with proposed disruption of a larger Paradox-Central Colorado Trough Basin by exhumation of the Uncompahgre Uplift. Initial exhumation of the Amarillo-Wichita Uplift to the east would provide a unique ~530 Ma signal absent from source areas to the SW, and result in initial exhumation of the Ancestral Front Range. (2) Alternatively, deformation due to flat slab subduction along a hypothesized plate boundary to the SW suggests a SW-to-NE younging of exhumation. This hypothesis suggests a SW-derived Grenville signature, and would trigger uplift of the Uncompahgre first. We analyzed depositional environments, sediment dispersal patterns, and sediment and basement zircon U-Pb and (U-Th)/He ages in 3 locations in the Paradox Basin and Central Colorado Trough (CCT). The Paradox Basin exhibits an up-section transition in fluvial style that suggests a decrease in overbank stability and increased lateral migration. Similarly, the CCT records a long-term progradation of depositional environments from marginal marine to fluvial, indicating that sediment supply in both basins outpaced accommodation. Preliminary provenance results indicate little to no input from the Amarillo-Wichita uplift in either basin despite uniformly westward sediment dispersal systems in both basins. Results also show that the Uncompahgre Uplift was the source for sediment throughout Paradox Basin deposition. These observations are inconsistent with the predictions of scenario 1 above. Rather, they suggest either a synchronous response to tectonic stress across the ARM provinces or an SW-to-NE pattern of deformation.

Disentangling vegetation diversity from climate–energy and habitat heterogeneity for explaining animal geographic patterns

USGS Publications Warehouse

Jimenez-Alfaro, Borja; Chytry, Milan; Mucina, Ladislav; Grace, James B.; Rejmanek, Marcel

2016-01-01

Broad-scale animal diversity patterns have been traditionally explained by hypotheses focused on climate–energy and habitat heterogeneity, without considering the direct influence of vegetation structure and composition. However, integrating these factors when considering plant–animal correlates still poses a major challenge because plant communities are controlled by abiotic factors that may, at the same time, influence animal distributions. By testing whether the number and variation of plant community types in Europe explain country-level diversity in six animal groups, we propose a conceptual framework in which vegetation diversity represents a bridge between abiotic factors and animal diversity. We show that vegetation diversity explains variation in animal richness not accounted for by altitudinal range or potential evapotranspiration, being the best predictor for butterflies, beetles, and amphibians. Moreover, the dissimilarity of plant community types explains the highest proportion of variation in animal assemblages across the studied regions, an effect that outperforms the effect of climate and their shared contribution with pure spatial variation. Our results at the country level suggest that vegetation diversity, as estimated from broad-scale classifications of plant communities, may contribute to our understanding of animal richness and may be disentangled, at least to a degree, from climate–energy and abiotic habitat heterogeneity.

Monogamy in large bee societies: a stingless paradox.

PubMed

Jaffé, Rodolfo; Pioker-Hara, Fabiana C; Dos Santos, Charles F; Santiago, Leandro R; Alves, Denise A; de M P Kleinert, Astrid; Francoy, Tiago M; Arias, Maria C; Imperatriz-Fonseca, Vera L

2014-03-01

High genetic diversity is important for the functioning of large insect societies. Across the social Hymenoptera (ants, bees, and wasps), species with the largest colonies tend to have a high colony-level genetic diversity resulting from multiple queens (polygyny) or queens that mate with multiple males (polyandry). Here we studied the genetic structure of Trigona spinipes, a stingless bee species with colonies an order of magnitude larger than those of polyandrous honeybees. Genotypes of adult workers and pupae from 43 nests distributed across three Brazilian biomes showed that T. spinipes colonies are usually headed by one singly mated queen. Apart from revealing a notable exception from the general incidence of high genetic diversity in large insect societies, our results reinforce previous findings suggesting the absence of polyandry in stingless bees and provide evidence against the sperm limitation hypothesis for the evolution of polyandry. Stingless bee species with large colonies, such as T. spinipes, thus seem promising study models to unravel alternative mechanisms to increase genetic diversity within colonies or understand the adaptive value of low genetic diversity in large insect societies.

Monogamy in large bee societies: a stingless paradox

NASA Astrophysics Data System (ADS)

Jaffé, Rodolfo; Pioker-Hara, Fabiana C.; dos Santos, Charles F.; Santiago, Leandro R.; Alves, Denise A.; de M. P. Kleinert, Astrid; Francoy, Tiago M.; Arias, Maria C.; Imperatriz-Fonseca, Vera L.

2014-03-01

High genetic diversity is important for the functioning of large insect societies. Across the social Hymenoptera (ants, bees, and wasps), species with the largest colonies tend to have a high colony-level genetic diversity resulting from multiple queens (polygyny) or queens that mate with multiple males (polyandry). Here we studied the genetic structure of Trigona spinipes, a stingless bee species with colonies an order of magnitude larger than those of polyandrous honeybees. Genotypes of adult workers and pupae from 43 nests distributed across three Brazilian biomes showed that T. spinipes colonies are usually headed by one singly mated queen. Apart from revealing a notable exception from the general incidence of high genetic diversity in large insect societies, our results reinforce previous findings suggesting the absence of polyandry in stingless bees and provide evidence against the sperm limitation hypothesis for the evolution of polyandry. Stingless bee species with large colonies, such as T. spinipes, thus seem promising study models to unravel alternative mechanisms to increase genetic diversity within colonies or understand the adaptive value of low genetic diversity in large insect societies.

Coal ball formation and a soil extinction near the P-Tr boundary

NASA Astrophysics Data System (ADS)

Breecker, D.; Royer, D. L.

2017-12-01

Coal balls are calcium carbonate accumulations that commonly permineralize paleotropical PermoCarboniferous coal deposits and preserve exceptional specimens of the coal swamp flora. A widely applicable model for the origin of coal balls is lacking despite the study of these deposits for over a century. Two characteristics of coal balls have been particularly challenging to explain: 1) their temporal range is restricted to the PermoCarboniferous and 2) their typical oxygen isotope and elemental compositions paradoxically indicate freshwater and marine origins, respectively. We propose a new model for coal ball formation. The first step in our model is the episodic delivery of seawater and marine carbonate sediment to coastal mires. Next, these waters are diluted by freshwater and the carbonates dissolve at the elevated pCO2 of the mire subsurface. Finally, as waters flow laterally through stands of arborescent lycopsids, aqueous CO2 in the pore spaces of the peat escapes by diffusion through the air-filled lycopsid rootlets into the overlying water column, where some rootlets are thought to have extended. The CO2 escape drives calcite precipitation in the soil zone. This model explains the narrow temporal occurrence of coal balls, which coincides with the peak diversity of arborescent lycopsids. It also resolves the geochemical conundrum; dilution by freshwater can result in relatively low pore water δ18O values without preventing high-Mg calcite formation. Furthermore, we show mathematically that for published densities of arborescent lycopsid root mats and for reasonable rates of lateral water flow and vertical peat accumulation, CO2 could escape rapidly enough through the rootlets to fill >35% of the porosity with calcite before substantial burial (top several decimeters of peat), explaining the exceptional preservation of coal swamp flora. Therefore, we suggest that coal balls are pedogenic in origin and that their disappearance from the rock record represents the first documented soil extinction on a vegetated planet.

Another look at North Sea pole tide dynamics

NASA Technical Reports Server (NTRS)

Dickman, S. R.; Preisig, J. R.

1986-01-01

The mechanism proposed by Wunsch (1974) to explain pole tide observations in the North Sea is evaluated. Wunsch's equations governing pole tide in the North Sea are presented, and solutions for correcting the depth, stream function, and deviation of the tidal height from the equilibrium values are described. The similarity between the Stokes paradox and the tidal equations of the North Sea, and the need for inclusion of inertial terms in the tidal equations are discussed.

Weak measurements measure probability amplitudes (and very little else)

NASA Astrophysics Data System (ADS)

Sokolovski, D.

2016-04-01

Conventional quantum mechanics describes a pre- and post-selected system in terms of virtual (Feynman) paths via which the final state can be reached. In the absence of probabilities, a weak measurement (WM) determines the probability amplitudes for the paths involved. The weak values (WV) can be identified with these amplitudes, or their linear combinations. This allows us to explain the ;unusual; properties of the WV, and avoid the ;paradoxes; often associated with the WM.

Hitherto unknown shear rupture mechanism as a source of instability in intact hard rocks at highly confined compression

NASA Astrophysics Data System (ADS)

Tarasov, Boris G.

2014-05-01

Today, frictional shear resistance along pre-existing faults is considered to be the lower limit on rock shear strength for confined conditions corresponding to the seismogenic layer. This paper introduces a recently identified shear rupture mechanism providing a paradoxical feature of hard rocks - the possibility of shear rupture propagation through the highly confined intact rock mass at shear stress levels significantly less than frictional strength. In the new mechanism, the rock failure associated with consecutive creation of small slabs (known as ‘domino-blocks') from the intact rock in the rupture tip is driven by a fan-shaped domino structure representing the rupture head. The fan-head combines such unique features as: extremely low shear resistance, self-sustaining stress intensification, and self-unbalancing conditions. Due to this the failure process caused by the mechanism is very dynamic and violent. This makes it impossible to directly observe and study the mechanism and can explain why the mechanism has not been detected before. This paper provides physical motivation for the mechanism, based upon side effects accompanying the failure process. Physical and mathematical models of the mechanism presented in the paper explain unique and paradoxical features of the mechanism. The new shear rupture mechanism allows a novel point of view for understanding the nature of spontaneous failure processes in hard rocks including earthquakes.

Quantum Quasi-Paradoxes and Quantum Sorites Paradoxes

NASA Astrophysics Data System (ADS)

Smarandache, Florentin

2009-03-01

There can be generated many paradoxes or quasi-paradoxes that may occur from the combination of quantum and non-quantum worlds in physics. Even the passage from the micro-cosmos to the macro-cosmos, and reciprocally, can generate unsolved questions or counter-intuitive ideas. We define a quasi-paradox as a statement which has a prima facie self-contradictory support or an explicit contradiction, but which is not completely proven as a paradox. We present herein four elementary quantum quasi-paradoxes and their corresponding quantum Sorites paradoxes, which form a class of quantum quasi-paradoxes.

Contrasting changes in taxonomic vs. functional diversity of tropical fish communities after habitat degradation.

PubMed

Villéger, Sébastien; Ramos Miranda, Julia; Flores Hernández, Domingo; Mouillot, David

2010-09-01

Human activities have strong impacts on ecosystem functioning through their effect on abiotic factors and on biodiversity. There is also growing evidence that species functional traits link changes in species composition and shifts in ecosystem processes. Hence, it appears to be of utmost importance to quantify modifications in the functional structure of species communities after human disturbance in addition to changes in taxonomic structure. Despite this fact, there is still little consensus on the actual impacts of human-mediated habitat alteration on the components of biodiversity, which include species functional traits. Therefore, we studied changes in taxonomic diversity (richness and evenness), in functional diversity, and in functional specialization of estuarine fish communities facing drastic environmental and habitat alterations. The Terminos Lagoon (Gulf of Mexico) is a tropical estuary of primary concern for its biodiversity, its habitats, and its resource supply, which have been severely impacted by human activities. Fish communities were sampled in four zones of the Terminos Lagoon 18 years apart (1980 and 1998). Two functions performed by fish (food acquisition and locomotion) were studied through the measurement of 16 functional traits. Functional diversity of fish communities was quantified using three independent components: richness, evenness, and divergence. Additionally, we measured the degree of functional specialization in fish communities. We used a null model to compare the functional and the taxonomic structure of fish communities between 1980 and 1998. Among the four largest zones studied, three did not show strong functional changes. In the northern part of the lagoon, we found an increase in fish richness but a significant decrease of functional divergence and functional specialization. We explain this result by a decline of specialized species (i.e., those with particular combinations of traits), while newly occurring species are redundant with those already present. The species that decreased in abundance have functional traits linked to seagrass habitats that regressed consecutively to increasing eutrophication. The paradox found in our study highlights the need for a multifaceted approach in the assessment of biodiversity changes in communities under pressure.

The placenta: a multifaceted, transient organ

PubMed Central

Burton, Graham J.; Fowden, Abigail L.

2015-01-01

The placenta is arguably the most important organ of the body, but paradoxically the most poorly understood. During its transient existence, it performs actions that are later taken on by diverse separate organs, including the lungs, liver, gut, kidneys and endocrine glands. Its principal function is to supply the fetus, and in particular, the fetal brain, with oxygen and nutrients. The placenta is structurally adapted to achieve this, possessing a large surface area for exchange and a thin interhaemal membrane separating the maternal and fetal circulations. In addition, it adopts other strategies that are key to facilitating transfer, including remodelling of the maternal uterine arteries that supply the placenta to ensure optimal perfusion. Furthermore, placental hormones have profound effects on maternal metabolism, initially building up her energy reserves and then releasing these to support fetal growth in later pregnancy and lactation post-natally. Bipedalism has posed unique haemodynamic challenges to the placental circulation, as pressure applied to the vena cava by the pregnant uterus may compromise venous return to the heart. These challenges, along with the immune interactions involved in maternal arterial remodelling, may explain complications of pregnancy that are almost unique to the human, including pre-eclampsia. Such complications may represent a trade-off against the provision for a large fetal brain. PMID:25602070

Antagonistic Phenomena in Network Dynamics

NASA Astrophysics Data System (ADS)

Motter, Adilson E.; Timme, Marc

2018-03-01

Recent research on the network modeling of complex systems has led to a convenient representation of numerous natural, social, and engineered systems that are now recognized as networks of interacting parts. Such systems can exhibit a wealth of phenomena that not only cannot be anticipated from merely examining their parts, as per the textbook definition of complexity, but also challenge intuition even when considered in the context of what is now known in network science. Here, we review the recent literature on two major classes of such phenomena that have far-reaching implications: (a) antagonistic responses to changes of states or parameters and (b) coexistence of seemingly incongruous behaviors or properties - both deriving from the collective and inherently decentralized nature of the dynamics. They include effects as diverse as negative compressibility in engineered materials, rescue interactions in biological networks, negative resistance in fluid networks, and the Braess paradox occurring across transport and supply networks. They also include remote synchronization, chimera states, and the converse of symmetry breaking in brain, power-grid, and oscillator networks as well as remote control in biological and bioinspired systems. By offering a unified view of these various scenarios, we suggest that they are representative of a yet broader class of unprecedented network phenomena that ought to be revealed and explained by future research.

Androgenesis: where males hijack eggs to clone themselves

PubMed Central

2016-01-01

Androgenesis is a form of quasi-sexual reproduction in which a male is the sole source of the nuclear genetic material in the embryo. Two types of androgenesis occur in nature. Under the first type, females produce eggs without a nucleus and the embryo develops from the male gamete following fertilization. Evolution of this type of androgenesis is poorly understood as the parent responsible for androgenesis (the mother) gains no benefit from it. Ultimate factors driving the evolution of the second type of androgenesis are better understood. In this case, a zygote is formed between a male and a female gamete, but the female genome is eliminated. When rare, androgenesis with genome elimination is favoured because an androgenesis-determining allele has twice the reproductive success of an allele that determines sexual reproduction. Paradoxically, except in hermaphrodites, a successful androgenetic strain can drive such a male-biased sex ratio that the population goes extinct. This likely explains why androgenesis with genome elimination appears to be rarer than androgenesis via non-nucleate eggs, although both forms are either very rare or remain largely undetected in nature. Nonetheless, some highly invasive species including ants and freshwater clams are androgenetic, for reasons that are largely unexplained. This article is part of the themed issue ‘Weird sex: the underappreciated diversity of sexual reproduction’. PMID:27619698

Effects of sub-clinical psychosis and cognitive insight on psychological well-being: a structural equation model.

PubMed

Weintraub, Marc J; Weisman de Mamani, Amy

2015-03-30

Psychological well-being has been widely researched along the psychosis spectrum, and increased psychotic symptoms are generally associated with worse well-being. Additionally, the construct of insight has been extensively studied in schizophrenia. While having greater insight has many benefits for those with schizophrenia, a paradox exists in which greater insight is also associated with poorer psychological well-being. However, it is unclear whether the link between insight and poor well-being occurs only once serious psychopathology has been established, or whether this is a more universal process seen even at lower levels on the psychosis spectrum. We used a structural modeling approach in an ethnically diverse, non-clinical sample of 420 undergraduates to evaluate the association between sub-clinical psychosis, cognitive insight and psychological well-being. As hypothesized, results indicated that sub-clinical psychotic symptoms were negatively associated with psychological well-being. The insight paradox was also substantiated, as greater cognitive insight was associated with worse psychological well-being. However, cognitive insight did not moderate the association between symptoms and well-being. The link between sub-clinical psychotic symptoms and psychological well-being as well as the insight paradox appears to emerge even before reaching threshold for a psychotic disorder. Research and clinical implications are discussed. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Non-B-Form DNA Is Enriched at Centromeres

PubMed Central

Henikoff, Steven

2018-01-01

Abstract Animal and plant centromeres are embedded in repetitive “satellite” DNA, but are thought to be epigenetically specified. To define genetic characteristics of centromeres, we surveyed satellite DNA from diverse eukaryotes and identified variation in <10-bp dyad symmetries predicted to adopt non-B-form conformations. Organisms lacking centromeric dyad symmetries had binding sites for sequence-specific DNA-binding proteins with DNA-bending activity. For example, human and mouse centromeres are depleted for dyad symmetries, but are enriched for non-B-form DNA and are associated with binding sites for the conserved DNA-binding protein CENP-B, which is required for artificial centromere function but is paradoxically nonessential. We also detected dyad symmetries and predicted non-B-form DNA structures at neocentromeres, which form at ectopic loci. We propose that centromeres form at non-B-form DNA because of dyad symmetries or are strengthened by sequence-specific DNA binding proteins. This may resolve the CENP-B paradox and provide a general basis for centromere specification. PMID:29365169

Saturn's F Ring Core: Calm in the Midst of Chaos

NASA Technical Reports Server (NTRS)

Cuzzi, J. N.; Whizin, A. D.; Hogan, R. C.; Dobrovolskis, A. R.; Dones, L.; Showalter. M. R.; Colwell, J. E.; Scargle, J. D.

2013-01-01

The long-term stability of the narrow F Ring core has been hard to understand. Instead of acting as "shepherds", Prometheus and Pandora together stir the vast preponderance of the region into a chaotic state, consistent with the orbits of newly discovered objects like S/2004S6. We show how a comb of very narrow radial locations of high stability in semimajor axis is embedded within this otherwise chaotic region. The stability of these semimajor axes relies fundamentally on the unusual combination of rapid apse precession and long synodic period which characterizes the region. This situation allows stable "antiresonances" to fall on or very close to traditional Lindblad resonances which, under more common circumstances, are destabilizing. We present numerical integrations of tens of thousands of test particles over tens of thousands of Prometheus orbits that map out the effect. The stable antiresonance zones are most stable in a subset of the region where Prometheus first-order resonances are least cluttered by Pandora resonances. This region of optimum stability is paradoxically closer to Prometheus than a location more representative of "torque balance", helping explain a longstanding paradox. One stable zone corresponds closely to the currently observed semimajor axis of the F Ring core. While the model helps explain the stability of the narrow F Ring core, it does not explain why the F Ring material all shares a common apse longitude; we speculate that collisional damping at the preferred semimajor axis (not included in the current simulations) may provide that final step. Essentially, we find that the F Ring core is not confined by a combination of Prometheus and Pandora, but a combination of Prometheus and precession.

Nitrogen loss and oxygen paradox in full-scale biofiltration for drinking water treatment.

PubMed

Yu, Xin; Qi, Zhihua; Zhang, Xiaojian; Yu, Ping; Liu, Bo; Zhang, Limin; Fu, Liang

2007-04-01

The nitrogen loss and DO paradox in full-scale biofiltration for drinking water treatment and the possible pathway responsible for them were investigated. A highly contaminated source water was treated at Pinghu Surface Water Plant using four biofilters, which resulted in a steady removal of NH(4)(+)-N (2.67mg/L), a great DO consumption (8.86 mg/L) and an increase in the concentration of NO(3)(-)-N (1.77mg/L). The nitrogen and DO balances indicated that about 13 NH(4)(+)-N was lost and the actual DO consumption was about 30% lower than the theoretical DO demand if nitrification was regarded as the only pathway to remove NH(4)(+)-N. The analysis of correlation coefficients analysis between several factors and the nitrogen loss suggested that "Aerobic deammonification", the coupling of shortcut nitrification and the anaerobic ammonia oxidation (Anammox) in an aerobic environment, might be the most probable pathways to explain the occurrence of these phenomena. According to this mechanism, about 57% NH(4)(+)-N was removed through complete nitrification and about 21.5% NH(4)(+)-N was incompletely nitrified into NO(2)(-)-N. The latter then involved in Anammox as the electron acceptor with the remaining NH(4)(+)-N as the electron donor. Since the Anammox reaction is anaerobic, the nitrogen loss and DO paradox can be justified.

Fuzzy spaces topology change and BH thermodynamics

NASA Astrophysics Data System (ADS)

Silva, C. A. S.; Landim, R. R.

2014-03-01

What is the ultimate fate of something that falls into a black hole? From this question arises one of the most intricate problems of modern theoretical physics: the black hole information loss paradox. Bekenstein and Hawking have been shown that the entropy in a black hole is proportional to the surface area of its event horizon, which should be quantized in a multiple of the Planck area. This led G.'t Hooft and L. Susskind to propose the holographic principle which states that all the information inside the black hole can be stored on its event horizon. From this results, one may think if the solution to the information paradox could lies in the quantum properties of the black hole horizon. One way to quantize the event horizon is to see it as a fuzzy sphere, which posses a closed relation with Hopf algebras. This relation makes possible a topology change process where a fuzzy sphere splits in two others. In this work it will be shown that, if one quantize the black hole event horizon as a fuzzy sphere taking into account its quantum symmetry properties, a topology change process to black holes can be defined without break unitarity or locality, and we can obtain a possible solution to the information paradox. Moreover, we show that this model can explain the origin of the black hole entropy, and why black holes obey a generalized second law of thermodynamics.

Theoretical implications of the neurotic paradox as a problem in behavior theory: An experimental resolution

PubMed Central

Stampfl, Thomas G.

1987-01-01

Why do human phobias last for months or years when such behavior should undergo extinction? This failure of extinction or persistence of self-defeating behavior of human disorders was labeled by Mowrer as the neurotic paradox. The paradox is cited by an ever-increasing number of critics who challenge any laboratory-based learning model of human psychopathology. Laboratory research, of course, omits essential requirements in the analysis of behavior, and the principles derived from such analyses must be combined in order to explain complex human behavaior. Validation for a behavioral model can thus be achieved if (a) basic principles inferred from observation of humans treated with a laboratory-derived extinction procedure (e.g., implosive therapy) are combined with (b) principles examined in laboratory research that are combined to generate unique predictions that correspond to known features of human phobic behavior. The latter evidence is briefly reviewed in research demonstrating sustained responding over one thousand consecutive active avoidance responses with complete avoidance of the “phobic” CS for an initial single shock trial. Differential reinforcement for responses to early sequential stimuli depends on minimal work requirement, and reinforcement by timeout from avoidance. This combination of factors effectively precludes extinction to main conditioned aversive stimuli for nonhumans, as it does for human phobias. Support for a laboratory model of human phobia is thereby attained. PMID:22477974

The multiple facets of Peto's paradox: a life-history model for the evolution of cancer suppression.

PubMed

Brown, Joel S; Cunningham, Jessica J; Gatenby, Robert A

2015-07-19

Large animals should have higher lifetime probabilities of cancer than small animals because each cell division carries an attendant risk of mutating towards a tumour lineage. However, this is not observed--a (Peto's) paradox that suggests large and/or long-lived species have evolved effective cancer suppression mechanisms. Using the Euler-Lotka population model, we demonstrate the evolutionary value of cancer suppression as determined by the 'cost' (decreased fecundity) of suppression verses the 'cost' of cancer (reduced survivorship). Body size per se will not select for sufficient cancer suppression to explain the paradox. Rather, cancer suppression should be most extreme when the probability of non-cancer death decreases with age (e.g. alligators), maturation is delayed, fecundity rates are low and fecundity increases with age. Thus, the value of cancer suppression is predicted to be lowest in the vole (short lifespan, high fecundity) and highest in the naked mole rat (long lived with late female sexual maturity). The life history of pre-industrial humans likely selected for quite low levels of cancer suppression. In modern humans that live much longer, this level results in unusually high lifetime cancer risks. The model predicts a lifetime risk of 49% compared with the current empirical value of 43%. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Explaining the apparent paradox of persistent selection for early flowering.

PubMed

Austen, Emily J; Rowe, Locke; Stinchcombe, John R; Forrest, Jessica R K

2017-08-01

Decades of observation in natural plant populations have revealed pervasive phenotypic selection for early flowering onset. This consistent pattern seems at odds with life-history theory, which predicts stabilizing selection on age and size at reproduction. Why is selection for later flowering rare? Moreover, extensive evidence demonstrates that flowering time can and does evolve. What maintains ongoing directional selection for early flowering? Several non-mutually exclusive processes can help to reconcile the apparent paradox of selection for early flowering. We outline four: selection through other fitness components may counter observed fecundity selection for early flowering; asymmetry in the flowering-time-fitness function may make selection for later flowering hard to detect; flowering time and fitness may be condition-dependent; and selection on flowering duration is largely unaccounted for. In this Viewpoint, we develop these four mechanisms, and highlight areas where further study will improve our understanding of flowering-time evolution. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

A neural basis for the spatial suppression of visual motion perception

PubMed Central

Liu, Liu D; Haefner, Ralf M; Pack, Christopher C

2016-01-01

In theory, sensory perception should be more accurate when more neurons contribute to the representation of a stimulus. However, psychophysical experiments that use larger stimuli to activate larger pools of neurons sometimes report impoverished perceptual performance. To determine the neural mechanisms underlying these paradoxical findings, we trained monkeys to discriminate the direction of motion of visual stimuli that varied in size across trials, while simultaneously recording from populations of motion-sensitive neurons in cortical area MT. We used the resulting data to constrain a computational model that explained the behavioral data as an interaction of three main mechanisms: noise correlations, which prevented stimulus information from growing with stimulus size; neural surround suppression, which decreased sensitivity for large stimuli; and a read-out strategy that emphasized neurons with receptive fields near the stimulus center. These results suggest that paradoxical percepts reflect tradeoffs between sensitivity and noise in neuronal populations. DOI: http://dx.doi.org/10.7554/eLife.16167.001 PMID:27228283

"Macho men" and preventive health care: implications for older men in different social classes.

PubMed

Springer, Kristen W; Mouzon, Dawne M

2011-06-01

The gender paradox in mortality--where men die earlier than women despite having more socioeconomic resources--may be partly explained by men's lower levels of preventive health care. Stereotypical notions of masculinity reduce preventive health care; however, the relationship between masculinity, socioeconomic status (SES), and preventive health care is unknown. Using the Wisconsin Longitudinal Study, the authors conduct a population-based assessment of masculinity beliefs and preventive health care, including whether these relationships vary by SES. The results show that men with strong masculinity beliefs are half as likely as men with more moderate masculinity beliefs to receive preventive care. Furthermore, in contrast to the well-established SES gradient in health, men with strong masculinity beliefs do not benefit from higher education and their probability of obtaining preventive health care decreases as their occupational status, wealth, and/or income increases. Masculinity may be a partial explanation for the paradox of men's lower life expectancy, despite their higher SES.

Species mtDNA genetic diversity explained by infrapopulation size in a host-symbiont system.

PubMed

Doña, Jorge; Moreno-García, Marina; Criscione, Charles D; Serrano, David; Jovani, Roger

2015-12-01

Understanding what shapes variation in genetic diversity among species remains a major challenge in evolutionary ecology, and it has been seldom studied in parasites and other host-symbiont systems. Here, we studied mtDNA variation in a host-symbiont non-model system: 418 individual feather mites from 17 feather mite species living on 17 different passerine bird species. We explored how a surrogate of census size, the median infrapopulation size (i.e., the median number of individual parasites per infected host individual), explains mtDNA genetic diversity. Feather mite species genetic diversity was positively correlated with mean infrapopulation size, explaining 34% of the variation. As expected from the biology of feather mites, we found bottleneck signatures for most of the species studied but, in particular, three species presented extremely low mtDNA diversity values given their infrapopulation size. Their star-like haplotype networks (in contrast with more reticulated networks for the other species) suggested that their low genetic diversity was the consequence of severe bottlenecks or selective sweeps. Our study shows for the first time that mtDNA diversity can be explained by infrapopulation sizes, and suggests that departures from this relationship could be informative of underlying ecological and evolutionary processes.

Network-specific mechanisms may explain the paradoxical effects of carbamazepine and phenytoin.

PubMed

Thomas, Evan A; Petrou, Steven

2013-07-01

A common notion of the mechanism by which the antiepileptic drugs (AEDs) carbamazepine and phenytoin act is that they block sodium channels by binding preferentially to the inactivated state, thereby allowing normal neuronal firing while blocking ictal activity. However, these drugs have unpredictable efficacy and, in some cases, may exacerbate seizures. Previous studies have suggested that reducing sodium channel availability in the dentate gyrus (DG) paradoxically increases excitability. We used a biophysically detailed computer model of the DG to test the hypothesis that AEDs increase excitability by disproportionately reducing negative feedback mechanisms. We built a Markov model of sodium channel gating that reproduces responses to voltage clamp experiments in the presence of carbamazepine and phenytoin. We incorporated this validated Markov model into a biophysically realistic computer model of DG neurons and networks. Simulated drug concentrations were similar to those measured in cerebral spinal fluid in medicated patients. Single neuron models were stimulated with current injections, and networks were stimulated with perforant path synaptic input. In the network model, environmental effects were studied by introducing mossy fiber sprouting. As expected, drugs reduced sodium channel availability, which in turn reduced action potential amplitude. This had only a small effect on action potential (AP) firing rate during brief (100 msec) current injections. Paradoxically, long current injections (2,500 msec) increased AP firing rates. This was caused by reduced calcium entry and consequently reduced activation of calcium activated potassium channels. It is important to note that the main determinant of drug effect was resting membrane potential (RMP) and not action potential firing rate. Binding of phenytoin and carbamazepine is slow and, thus drug effects are largely determined by the long term state of the RMP. This paradoxical AP firing increase was dependent on the unusually large calcium-activated potassium conductances expressed by DG granule cells. This predicts that drug efficacy in a given network will depend on the precise makeup of conductances in the network. RMP is expected to vary with the level of activity in the network. We simulated the effects of drugs on single shot stimulus responses in networks with mossy fiber sprouting and varied the RMP in all neurons as a model for network activity. For an RMP of -50 mV, representing an active network, drugs had no effect, or in some cases, increased excitability. Drugs had an increasingly larger inhibitory effect on network responses as RMP decreased. An important prediction is that drugs will be unable to block ictal activity invading an active network. Our key findings are that drug effects depend on both intrinsic properties of the network and its behavioral state. This may explain the paradoxical and unpredictable effects of some AEDs on seizure control in some patients. Wiley Periodicals, Inc. © 2013 International League Against Epilepsy.

South Asian ethnicity and cardiovascular risk: the known, the unknown, and the paradox.

PubMed

Ahmed, Emad; El-Menyar, Ayman

2015-05-01

South Asians (SAs), in their countries or after migration, are at high risk of coronary artery disease (CAD) and mortality compared to other ethnic groups. It has been shown that >90% of CAD global risk could be attributed to 9 modifiable risk factors (RFs) worldwide. However, these conventional RFs may not fully explain this high risk of CAD among SAs. Therefore, attention has been directed toward nonconventional RFs. In this narrative review, we evaluate the conventional and emerging cardiovascular RFs characterizing SAs. These factors may explain the high morbidity and mortality among SAs. Further prospective studies are urgently needed to set algorithms for the optimal management of these RFs in high-risk populations like SAs. © The Author(s) 2014.

Sheet-like assemblies of spherical particles with point-symmetrical patches.

PubMed

Mani, Ethayaraja; Sanz, Eduardo; Roy, Soumyajit; Dijkstra, Marjolein; Groenewold, Jan; Kegel, Willem K

2012-04-14

We report a computational study on the spontaneous self-assembly of spherical particles into two-dimensional crystals. The experimental observation of such structures stabilized by spherical objects appeared paradoxical so far. We implement patchy interactions with the patches point-symmetrically (icosahedral and cubic) arranged on the surface of the particle. In these conditions, preference for self-assembly into sheet-like structures is observed. We explain our findings in terms of the inherent symmetry of the patches and the competition between binding energy and vibrational entropy. The simulation results explain why hollow spherical shells observed in some Keplerate-type polyoxometalates (POM) appear. Our results also provide an explanation for the experimentally observed layer-by-layer growth of apoferritin--a quasi-spherical protein.

Is life supernatural?

NASA Astrophysics Data System (ADS)

Levin, Gilbert V.

2015-09-01

The big question of the origin of life is examined. The paradox created by Pasteur's resounding edict: Life only comes from life, pitted against the need for spontaneous generation is explored. This seemingly dead-end conundrum contrasts sharply with the great progress we have made in understanding the evolution of the species since Darwin's revolutionary insight. The conditions and sources of energy that might have promoted non-living molecules and compounds to cross the sharp line from inert to living are contemplated. Abiotic synthesis might help explain the origin, but still fails to explain the moment of vitalization. A different approach to discovering when the inert becomes alive is proposed. The need for, and a way to bring forth, a "Bio-Einstein" to solve this penultimate question of life's origin are presented.

Factors influencing geographic patterns in diversity of forest bird communities of eastern Connecticut, USA

USGS Publications Warehouse

Craig, Robert J.; Klaver, Robert W.

2012-01-01

At regional scales, the most important variables associated with diversity are latitudinally-based temperature and net primary productivity, although diversity is also influenced by habitat. We examined bird species richness, community density and community evenness in forests of eastern Connecticut to determine whether: 1) spatial and seasonal patterns exist in diversity, 2) energy explains the greatest proportion of variation in diversity parameters, 3) variation in habitat explains remaining diversity variance, and 4) seasonal shifts in diversity provide clues about how environmental variables shape communities. We sought to discover if our data supported predictions of the species–energy hypothesis. We used the variable circular plot technique to estimate bird populations and quantified the location, elevation, forest type, vegetation type, canopy cover, moisture regime, understory density and primary production for the study sites. We found that 1) summer richness and population densities are roughly equal in northeastern and southeastern Connecticut, whereas in winter both concentrate toward the coast, 2) variables linked with temperature explained much of the patterns in winter diversity, but energy-related variables showed little relationship to summer diversity, 3) the effect of habitat variables on diversity parameters predominated in summer, although their effect was weak, 4) contrary to theory, evenness increased from summer to winter, and 5) support for predictions of species–energy theory was primarily restricted to winter data. Although energy and habitat played a role in explaining community patterns, they left much of the variance in regional diversity unexplained, suggesting that a large stochastic component to diversity also may exist.

Health impact assessment in multinationals: A case study of the Royal Dutch/Shell Group

DOE Office of Scientific and Technical Information (OSTI.GOV)

Birley, Martin

2005-10-15

Health impact assessment is part of the risk management process of multinational corporations/companies. Sexually transmitted infections, including HIV/AIDS, and the 'paradox of plenty' are used as examples of the challenges they face. The 'business case' for impact assessment is explained. The policies, procedures, standards, and activities used by Shell to manage such risks are described. An approach to capacity building and competency development is presented that applies to both company staff and external contractors.

Dirac Particles' Hawking Radiation from a Schwarzschild Black Hole

NASA Astrophysics Data System (ADS)

He, Xiao-Kai; Liu, Wen-Biao

2007-08-01

Considering energy conservation and the backreaction of particles to spacetime, we investigate the massless/massive Dirac particles' Hawking radiation from a Schwarzschild black hole. The exact expression of the emission rate near the horizon is obtained and the result indicates that Hawking radiation spectrum is not purely thermal. The result obtained is consistent with the results obtained before. It satisfies the underlying unitary theory and offers a possible mechanism to explain the information loss paradox. Whereas the improved Damour-Ruffini method is more concise and understandable.

Simpson's Paradox, Lord's Paradox, and Suppression Effects are the same phenomenon – the reversal paradox

PubMed Central

Tu, Yu-Kang; Gunnell, David; Gilthorpe, Mark S

2008-01-01

This article discusses three statistical paradoxes that pervade epidemiological research: Simpson's paradox, Lord's paradox, and suppression. These paradoxes have important implications for the interpretation of evidence from observational studies. This article uses hypothetical scenarios to illustrate how the three paradoxes are different manifestations of one phenomenon – the reversal paradox – depending on whether the outcome and explanatory variables are categorical, continuous or a combination of both; this renders the issues and remedies for any one to be similar for all three. Although the three statistical paradoxes occur in different types of variables, they share the same characteristic: the association between two variables can be reversed, diminished, or enhanced when another variable is statistically controlled for. Understanding the concepts and theory behind these paradoxes provides insights into some controversial or contradictory research findings. These paradoxes show that prior knowledge and underlying causal theory play an important role in the statistical modelling of epidemiological data, where incorrect use of statistical models might produce consistent, replicable, yet erroneous results. PMID:18211676

Environmental Predictors of Diversity in Recent Planktonic Foraminifera as Recorded in Marine Sediments

PubMed Central

Pearson, Paul N.; Dunkley Jones, Tom; Purvis, Andy

2016-01-01

Global diversity patterns are thought to result from a combination of environmental and historical factors. This study tests the set of ecological and evolutionary hypotheses proposed to explain the global variation in present-day coretop diversity in the macroperforate planktonic foraminifera, a clade with an exceptional fossil record. Within this group, marine surface sediment assemblages are thought to represent an accurate, although centennial to millennial time-averaged, representation of recent diversity patterns. Environmental variables chosen to capture ocean temperature, structure, productivity and seasonality were used to model a range of diversity measures across the world’s oceans. Spatial autoregressive models showed that the same broad suite of environmental variables were important in shaping each of the four largely independent diversity measures (rarefied species richness, Simpson’s evenness, functional richness and mean evolutionary age). Sea-surface temperature explains the largest portion of diversity in all four diversity measures, but not in the way predicted by the metabolic theory of ecology. Vertical structure could be linked to increased diversity through the strength of stratification, but not through the depth of the mixed layer. There is limited evidence that seasonal turnover explains diversity patterns. There is evidence for functional redundancy in the low-latitude sites. The evolutionary mechanism of deep-time stability finds mixed support whilst there is relatively little evidence for an out-of-the-tropics model. These results suggest the diversity patterns of planktonic foraminifera cannot be explained by any one environmental variable or proposed mechanism, but instead reflect multiple processes acting in concert. PMID:27851751

Environmental Predictors of Diversity in Recent Planktonic Foraminifera as Recorded in Marine Sediments.

PubMed

Fenton, Isabel S; Pearson, Paul N; Dunkley Jones, Tom; Purvis, Andy

2016-01-01

Global diversity patterns are thought to result from a combination of environmental and historical factors. This study tests the set of ecological and evolutionary hypotheses proposed to explain the global variation in present-day coretop diversity in the macroperforate planktonic foraminifera, a clade with an exceptional fossil record. Within this group, marine surface sediment assemblages are thought to represent an accurate, although centennial to millennial time-averaged, representation of recent diversity patterns. Environmental variables chosen to capture ocean temperature, structure, productivity and seasonality were used to model a range of diversity measures across the world's oceans. Spatial autoregressive models showed that the same broad suite of environmental variables were important in shaping each of the four largely independent diversity measures (rarefied species richness, Simpson's evenness, functional richness and mean evolutionary age). Sea-surface temperature explains the largest portion of diversity in all four diversity measures, but not in the way predicted by the metabolic theory of ecology. Vertical structure could be linked to increased diversity through the strength of stratification, but not through the depth of the mixed layer. There is limited evidence that seasonal turnover explains diversity patterns. There is evidence for functional redundancy in the low-latitude sites. The evolutionary mechanism of deep-time stability finds mixed support whilst there is relatively little evidence for an out-of-the-tropics model. These results suggest the diversity patterns of planktonic foraminifera cannot be explained by any one environmental variable or proposed mechanism, but instead reflect multiple processes acting in concert.

Island phytophagy: explaining the remarkable diversity of plant-feeding insects

PubMed Central

Joy, Jeffrey B.; Crespi, Bernard J.

2012-01-01

Plant-feeding insects have undergone unparalleled diversification among different plant taxa, yet explanations for variation in their diversity lack a quantitative, predictive framework. Island biogeographic theory has been applied to spatially discrete habitats but not to habitats, such as host plants, separated by genetic distance. We show that relationships between the diversity of gall-inducing flies and their host plants meet several fundamental predictions from island biogeographic theory. First, plant-taxon genetic distinctiveness, an integrator for long-term evolutionary history of plant lineages, is a significant predictor of variance in the diversity of gall-inducing flies among host-plant taxa. Second, range size and structural complexity also explain significant proportions of the variance in diversity of gall-inducing flies among different host-plant taxa. Third, as with other island systems, plant-lineage age does not predict species diversity. Island biogeographic theory, applied to habitats defined by genetic distance, provides a novel, comprehensive framework for analysing and explaining the diversity of plant-feeding insects and other host-specific taxa. PMID:22553094

Island phytophagy: explaining the remarkable diversity of plant-feeding insects.

PubMed

Joy, Jeffrey B; Crespi, Bernard J

2012-08-22

Plant-feeding insects have undergone unparalleled diversification among different plant taxa, yet explanations for variation in their diversity lack a quantitative, predictive framework. Island biogeographic theory has been applied to spatially discrete habitats but not to habitats, such as host plants, separated by genetic distance. We show that relationships between the diversity of gall-inducing flies and their host plants meet several fundamental predictions from island biogeographic theory. First, plant-taxon genetic distinctiveness, an integrator for long-term evolutionary history of plant lineages, is a significant predictor of variance in the diversity of gall-inducing flies among host-plant taxa. Second, range size and structural complexity also explain significant proportions of the variance in diversity of gall-inducing flies among different host-plant taxa. Third, as with other island systems, plant-lineage age does not predict species diversity. Island biogeographic theory, applied to habitats defined by genetic distance, provides a novel, comprehensive framework for analysing and explaining the diversity of plant-feeding insects and other host-specific taxa.

Interspecific diversity reduces and functionally substitutes for intraspecific variation in biofilm communities

PubMed Central

Kelvin Lee, Kai Wei; Hoong Yam, Joey Kuok; Mukherjee, Manisha; Periasamy, Saravanan; Steinberg, Peter D; Kjelleberg, Staffan; Rice, Scott A

2016-01-01

Diversity has a key role in the dynamics and resilience of communities and both interspecific (species) and intraspecific (genotypic) diversity can have important effects on community structure and function. However, a critical and unresolved question for understanding the ecology of a community is to what extent these two levels of diversity are functionally substitutable? Here we show, for a mixed-species biofilm community composed of Pseudomonas aeruginosa, P. protegens and Klebsiella pneumoniae, that increased interspecific diversity reduces and functionally substitutes for intraspecific diversity in mediating tolerance to stress. Biofilm populations generated high percentages of genotypic variants, which were largely absent in biofilm communities. Biofilms with either high intra- or interspecific diversity were more tolerant to SDS stress than biofilms with no or low diversity. Unexpectedly, genotypic variants decreased the tolerance of biofilm communities when experimentally introduced into the communities. For example, substituting P. protegens wild type with its genotypic variant within biofilm communities decreased SDS tolerance by twofold, apparently due to perturbation of interspecific interactions. A decrease in variant frequency was also observed when biofilm populations were exposed to cell-free effluents from another species, suggesting that extracellular factors have a role in selection against the appearance of intraspecific variants. This work demonstrates the functional substitution of inter- and intraspecific diversity for an emergent property of biofilms. It also provides a potential explanation for a long-standing paradox in microbiology, in which morphotypic variants are common in laboratory grown biofilm populations, but are rare in diverse, environmental biofilm communities. PMID:26405829

Genetic Risk Score of NOS Gene Variants Associated with Myocardial Infarction Correlates with Coronary Incidence across Europe

PubMed Central

Carreras-Torres, Robert; Kundu, Suman; Zanetti, Daniela; Esteban, Esther

2014-01-01

Coronary artery disease (CAD) mortality and morbidity is present in the European continent in a four-fold gradient across populations, from the South (Spain and France) with the lowest CAD mortality, towards the North (Finland and UK). This observed gradient has not been fully explained by classical or single genetic risk factors, resulting in some cases in the so called Southern European or Mediterranean paradox. Here we approached population genetic risk estimates using genetic risk scores (GRS) constructed with single nucleotide polymorphisms (SNP) from nitric oxide synthases (NOS) genes. These SNPs appeared to be associated with myocardial infarction (MI) in 2165 cases and 2153 controls. The GRSs were computed in 34 general European populations. Although the contribution of these GRS was lower than 1% between cases and controls, the mean GRS per population was positively correlated with coronary incidence explaining 65–85% of the variation among populations (67% in women and 86% in men). This large contribution to CAD incidence variation among populations might be a result of colinearity with several other common genetic and environmental factors. These results are not consistent with the cardiovascular Mediterranean paradox for genetics and support a CAD genetic architecture mainly based on combinations of common genetic polymorphisms. Population genetic risk scores is a promising approach in public health interventions to develop lifestyle programs and prevent intermediate risk factors in certain subpopulations with specific genetic predisposition. PMID:24806096

Paradoxes of thermodynamics of swelling equilibria of polymers in liquids and vapors.

PubMed

Davankov, Vadim A; Pastukhov, Alexander V

2011-12-29

An automatic registration of the changing size of a single spherical microbead of a cross-linked polymer was applied for studying the swelling process of the bead by the sorption of vapors and/or liquids. Many representatives of all three basic types of polymeric networks, gel-type, hypercrosslinked, and macroporous, were examined. Only the first two display large volume changes and prove suitable for following the kinetics and extent of swelling by the above dilatometric technique. The results unambiguously prove that swelling of all polymeric networks in liquids is always higher than in corresponding saturated vapors (Schroeder's paradox). The general nature of this phenomenon implies that the absolute activity of any sorbate in its liquid form is always larger than in the form of its saturated vapor. Surprisingly, gels with any solvent contents, which fall into the broad range between the vapor-equilibrated and liquid-equilibrated extreme contents, retain their volumes constant in the saturated vapor atmosphere. This paradox of a wide range of gels swollen to a different extent and, nevertheless, standing in equilibrium with saturated vapor is explained by the specificity of the network polymers, namely, that the energy of the solvent-polymer interactions is easily compensated by the energy of remaining between-chain interactions at any solvent content in the above range. Therefore, the strain-free swollen gels do not generate enhanced vapor pressure, but neither display the ability to take up more sorbate from its vapor. © 2011 American Chemical Society

The paradox of non-evidence based, publicly funded complementary alternative medicine in the English National Health Service: An explanation.

PubMed

Sheppard, Maria K

2015-10-01

Despite the unproven effectiveness of many practices that are under the umbrella term 'complementary alternative medicine' (CAM), there is provision of CAM within the English National Health Service (NHS). Moreover, although the National Institute for Health and Care Excellence was established to promote scientifically validated medicine in the NHS, the paradox of publicly funded, non-evidence based CAM can be explained as linked with government policy of patient choice and specifically patient treatment choice. Patient choice is useful in the political and policy discourse as it is open to different interpretations and can be justified by policy-makers who rely on the traditional NHS values of equity and universality. Treatment choice finds expression in the policy of personalised healthcare linked with patient responsibilisation which finds resonance in the emphasis CAM places on self-care and self-management. More importantly, however, policy-makers also use patient choice and treatment choice as a policy initiative with the objective of encouraging destabilisation of the entrenched healthcare institutions and practices considered resistant to change. This political strategy of system reform has the unintended, paradoxical consequence of allowing for the emergence of non-evidence based, publicly funded CAM in the NHS. The political and policy discourse of patient choice thus trumps evidence based medicine, with patients that demand access to CAM becoming the unwitting beneficiaries. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

The immigrant paradox among Asian American women: are disparities in the burden of depression and anxiety paradoxical or explicable?

PubMed

Lau, Anna S; Tsai, William; Shih, Josephine; Liu, Lisa L; Hwang, Wei-Chin; Takeuchi, David T

2013-10-01

We evaluated potential explanations for advantaged mental health status among immigrant Asian American women compared to U.S.-born Asian American women. In a nationally representative sample of 1,030 women (185 U.S.-born, 368 early-life immigrants [arrived before 25 years of age], 477 late-life immigrants), we examined the hypothesis that increased exposure to social risk factors mediate nativity-based differences in lifetime prevalence of depression and anxiety disorders. Indicators of social class were also examined as protective factors enjoyed by U.S.-born women that may suppress observed nativity-based disparities. We also examined whether there were group differences in reactivity to stress in predicting disorder. U.S.-born women were twice as likely as late-life immigrants to report lifetime history of depression (odds ratio [OR] = 2.03, 95% CI [1.35, 4.54]) and anxiety (OR = 2.12, 95% CI [1.34, 5.19]). Nativity differences in perceived discrimination, family conflict, and cultural conflict explained disparities in rates of disorder. There was no support for the contention that immigrant women were more psychologically hardy or resilient to social stress. Findings suggest that the gap in mental health status between U.S.- and foreign-born Asian American women would indeed be magnified if differences in social status were accounted for, but also that ready explanations for the so-called immigrant paradox are found in differential levels of reported stress exposure. (c) 2013 APA, all rights reserved.

The paradox of falling job satisfaction with rising job stickiness in the German nursing workforce between 1990 and 2013.

PubMed

Alameddine, Mohamad; Bauer, Jan Michael; Richter, Martin; Sousa-Poza, Alfonso

2017-08-29

Literature reports a direct relation between nurses' job satisfaction and their job retention (stickiness). The proper planning and management of the nursing labor market necessitates the understanding of job satisfaction and retention trends. The objectives of the study are to identify trends in, and the interrelation between, the job satisfaction and job stickiness of German nurses in the 1990-2013 period using a flexible specification for job satisfaction that includes different time periods and to also identify the main determinants of nurse job stickiness in Germany and test whether these determinants have changed over the last two decades. The development of job stickiness in Germany is depicted by a subset of data from the German Socio-Economic Panel (1990-2013), with each survey respondent assigned a unique identifier used to calculate the year-to-year transition probability of remaining in the current position. The changing association between job satisfaction and job stickiness is measured using job satisfaction data and multivariate regressions assessing whether certain job stickiness determinants have changed over the study period. Between 1990 and 2013, the job stickiness of German nurses increased from 83 to 91%, while their job satisfaction underwent a steady and gradual decline, dropping by 7.5%. We attribute this paradoxical result to the changing association between job satisfaction and job stickiness; that is, for a given level of job (dis)satisfaction, nurses show a higher stickiness rate in more recent years than in the past, which might be partially explained by the rise in part-time employment during this period. The main determinants of stickiness, whose importance has not changed in the past two decades, are wages, tenure, personal health, and household structure. The paradoxical relation between job satisfaction and job stickiness in the German nursing context could be explained by historical downsizing trends in hospitals, an East-West German nurse compensation gap, and an increase in the proportion of nurses employed on a part-time basis. A clearer analysis of each of these trends is thus essential for the development of evidence-based policies that enhance the job satisfaction and efficiency of the German nursing workforce.

Body mass index and mortality in acutely decompensated heart failure across the world: a global obesity paradox.

PubMed

Shah, Ravi; Gayat, Etienne; Januzzi, James L; Sato, Naoki; Cohen-Solal, Alain; diSomma, Salvatore; Fairman, Enrique; Harjola, Veli-Pekka; Ishihara, Shiro; Lassus, Johan; Maggioni, Aldo; Metra, Marco; Mueller, Christian; Mueller, Thomas; Parenica, Jiri; Pascual-Figal, Domingo; Peacock, William Frank; Spinar, Jindrich; van Kimmenade, Roland; Mebazaa, Alexandre

2014-03-04

This study sought to define the relationship between body mass index (BMI) and mortality in heart failure (HF) across the world and to identify specific groups in whom BMI may differentially mediate risk. Obesity is associated with incident HF, but it is paradoxically associated with better prognosis during chronic HF. We studied 6,142 patients with acute decompensated HF from 12 prospective observational cohorts followed-up across 4 continents. Primary outcome was all-cause mortality. Cox proportional hazards models and net reclassification index described associations of BMI with all-cause mortality. Normal-weight patients (BMI 18.5 to 25 kg/m(2)) were older with more advanced HF and lower cardiometabolic risk. Despite worldwide heterogeneity in clinical features across obesity categories, a higher BMI remained associated with decreased 30-day and 1-year mortality (11% decrease at 30 days; 9% decrease at 1 year per 5 kg/m(2); p < 0.05), after adjustment for clinical risk. The BMI obtained at index admission provided effective 1-year risk reclassification beyond current markers of clinical risk (net reclassification index 0.119, p < 0.001). Notably, the "protective" association of BMI with mortality was confined to persons with older age (>75 years; hazard ratio [HR]: 0.82; p = 0.006), decreased cardiac function (ejection fraction <50%; HR: 0.85; p < 0.001), no diabetes (HR: 0.86; p < 0.001), and de novo HF (HR: 0.89; p = 0.004). A lower BMI is associated with age, disease severity, and a higher risk of death in acute decompensated HF. The "obesity paradox" is confined to older persons, with decreased cardiac function, less cardiometabolic illness, and recent-onset HF, suggesting that aging, HF severity/chronicity, and metabolism may explain the obesity paradox. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Smoking paradox in the development of psoriatic arthritis among patients with psoriasis: a population-based study.

PubMed

Nguyen, Uyen-Sa D T; Zhang, Yuqing; Lu, Na; Louie-Gao, Qiong; Niu, Jingbo; Ogdie, Alexis; Gelfand, Joel M; LaValley, Michael P; Dubreuil, Maureen; Sparks, Jeffrey A; Karlson, Elizabeth W; Choi, Hyon K

2018-01-01

Smoking is associated with an increased risk of psoriatic arthritis (PsA) in the general population, but not among patients with psoriasis. We sought to clarify the possible methodological mechanisms behind this paradox. Using 1995-2015 data from The Health Improvement Network, we performed survival analysis to examine the association between smoking and incident PsA in the general population and among patients with psoriasis. We clarified the paradox using mediation analysis and conducted bias sensitivity analyses to evaluate the potential impact of index event bias and quantify its magnitude from uncontrolled/unmeasured confounders. Of 6.65 million subjects without PsA at baseline, 225 213 participants had psoriasis and 7057 developed incident PsA. Smoking was associated with an increased risk of PsA in the general population (HR 1.27; 95% CI 1.19 to 1.36), but with a decreased risk among patients with psoriasis (HR 0.91; 95% CI 0.84 to 0.99). Mediation analysis showed that the effect of smoking on the risk of PsA was mediated almost entirely through its effect on psoriasis. Bias-sensitivity analyses indicated that even when the relation of uncontrolled confounders to either smoking or PsA was modest (both HRs=~1.5), it could reverse the biased effect of smoking among patients with psoriasis (HR=0.9). In this large cohort representative of the UK general population, smoking was positively associated with PsA risk in the general population, but negatively associated among patients with psoriasis. Conditioning on a causal intermediate variable (psoriasis) may even reverse the association between smoking and PsA, potentially explaining the smoking paradox for the risk of PsA among patients with psoriasis. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Management outline of oral and maxillofacial missile injuries in Iraq: the value of the intermediate phase.

PubMed

Maki, Mohammed Hashim

2009-05-01

Oral and maxillofacial surgeons in Iraq are practicing in a paradoxical situation where a high number of extensive injuries are accompanied by limited resources. Steps of management should be followed cautiously in attempts to reduce residual deformities that characterize the end results of severe missile injuries. This study elucidate lessons extirpated from surgical experience in the management of diversity of causalities with special emphasis on the intermediate phase of management as well as different modalities of treatment, trying to get best benefit from available resources.

Tree aboveground carbon storage correlates with environmental gradients and functional diversity in a tropical forest

PubMed Central

Shen, Yong; Yu, Shixiao; Lian, Juyu; Shen, Hao; Cao, Honglin; Lu, Huanping; Ye, Wanhui

2016-01-01

Tropical forests play a disproportionately important role in the global carbon (C) cycle, but it remains unclear how local environments and functional diversity regulate tree aboveground C storage. We examined how three components (environments, functional dominance and diversity) affected C storage in Dinghushan 20-ha plot in China. There was large fine-scale variation in C storage. The three components significantly contributed to regulate C storage, but dominance and diversity of traits were associated with C storage in different directions. Structural equation models (SEMs) of dominance and diversity explained 34% and 32% of variation in C storage. Environments explained 26–44% of variation in dominance and diversity. Similar proportions of variation in C storage were explained by dominance and diversity in regression models, they were improved after adding environments. Diversity of maximum diameter was the best predictor of C storage. Complementarity and selection effects contributed to C storage simultaneously, and had similar importance. The SEMs disengaged the complex relationships among the three components and C storage, and established a framework to show the direct and indirect effects (via dominance and diversity) of local environments on C storage. We concluded that local environments are important for regulating functional diversity and C storage. PMID:27278688

How Can Intergroup Interaction Be Bad If Intergroup Contact Is Good? Exploring and Reconciling an Apparent Paradox in the Science of Intergroup Relations

PubMed Central

Page-Gould, Elizabeth

2015-01-01

The outcomes of social interactions among members of different groups (e.g., racial groups, political groups, sexual orientation groups) have long been of interest to psychologists. Two related literatures on the topic have emerged—the intergroup interaction literature and the intergroup contact literature—in which divergent conclusions have been reported. Intergroup interaction is typically found to have negative effects tied to intergroup bias, producing heightened stress, intergroup anxiety, or outgroup avoidance, whereas intergroup contact is typically found to have positive effects tied to intergroup bias, predicting lower intergroup anxiety and lower prejudice. We examine these paradoxical findings, proposing that researchers contributing to the two literatures are examining different levels of the same phenomenon and that methodological differences can account for the divide between the literatures. Further, we introduce a mathematical model by which the findings of the two literatures can be reconciled. We believe that adopting this model will streamline thinking in the field and will generate integrative new research in which investigators examine how a person’s experiences with diversity unfold. PMID:25987510

Relative importance of local habitat complexity and regional factors for assemblages of oribatid mites (Acari: Oribatida) in Sphagnum peat bogs.

PubMed

Minor, M A; Ermilov, S G; Philippov, D A; Prokin, A A

2016-11-01

We investigated communities of oribatid mites in five peat bogs in the north-west of the East European plain. We aimed to determine the extent to which geographic factors (latitude, separation distance), local environment (Sphagnum moss species, ground water level, biogeochemistry) and local habitat complexity (diversity of vascular plants and bryophytes in the surrounding plant community) influence diversity and community composition of Oribatida. There was a significant north-to-south increase in Oribatida abundance. In the variance partitioning, spatial factors explained 33.1 % of variability in abundance across samples; none of the environmental factors were significant. Across all bogs, Oribatida species richness and community composition were similar in Sphagnum rubellum and Sphagnum magellanicum, but significantly different and less diverse in Sphagnum cuspidatum. Sphagnum microhabitat explained 52.2 % of variability in Oribatida species richness, whereas spatial variables explained only 8.7 %. There was no distance decay in community similarity between bogs with increased geographical distance. The environmental variables explained 34.9 % of the variance in community structure, with vascular plants diversity, bryophytes diversity, and ground water level all contributing significantly; spatial variables explained 15.1 % of the total variance. Overall, only 50 % of the Oribatida community variance was explained by the spatial structure and environmental variables. We discuss relative importance of spatial and local environmental factors, and make general inferences about the formation of fauna in Sphagnum bogs.

Client cognitive responses to counselor paradoxical and nonparadoxical directives.

PubMed

Lee, D Y; Rossiter, B; Martin, J; Uhlemann, M R

1990-09-01

Client cognitive responses to counselor paradoxical and nonparadoxical directives were examined. It was predicted (a) that clients who received paradoxical symptom prescriptions would display a greater negativity toward the counselor and counseling than those who received nonparadoxical directives; and (b) that clients who received no rationale for the paradoxical directives would display a greater negativity than those who received a rationale. Thirty clients who had reported performance anxiety received one 45-minute counseling interview. Ten clients received paradoxical directives with a rationale, 10 received paradoxical directives with no rationale, and 10 received nonparadoxical directives. Results showed no significant differences in either client in-session negativity or out-of-session implementation of directives between the paradoxical and nonparadoxical conditions and between the rationale and no rationale paradoxical conditions. Possible implications of the findings are discussed.

Paying for health.

PubMed Central

Black, D

1991-01-01

Health care systems, irrespective of how they are financed, present the paradox that to some observers they appear as a major component of social benefits, while to other observers they seem both excessively costly and limited in their effectiveness. These differing perceptions may be explained in part by the diversity of the determinants of health and disease, only some of which are amenable to those preventive or therapeutic measures encompassed in a health care system--the majority of determinants being genetic, societal, or else uninfluenced by those interventions at present available within a health service. The share of national resources which should be devoted to health care, and the method of raising resources, are primarily matters for political decision; but a national system has advantages both of economy and of comprehensiveness. But when it comes to allocation of resources within the established health budget, the knowledge and skills of health professionals are essential to informed decision-making. The possibilities depend critically on the 'state of the art' at a given time, as is illustrated by the radical changes over time in what could be done for patients with renal failure; and health professionals are likely to be most aware of current options, and of how to choose between them. More speculatively, they are also less likely to confuse the attitudes appropriate to providing a service with those required to run a business. PMID:1941951

Modified Hawking radiation in a BTZ black hole using Damour Ruffini method

NASA Astrophysics Data System (ADS)

He, Xiaokai; Liu, Wenbiao

2007-09-01

Considering energy conservation, angular momentum conservation, and the particles' back reaction to space-time, the scalar particles' Hawking radiation from a BTZ black hole was investigated using Damour-Ruffini method. The exact expression of the emission rate near the horizon is obtained and the result indicates that Hawking radiation spectrum is not purely thermal. The result obtained is consistent with the previous literatures. It is in agreement with an underlying unitary theory and offers a possible mechanism to explain the information loss paradox. Whereas, the method is more concise and understandable.

An entangled web of crime: Bell's theorem as a short story

NASA Astrophysics Data System (ADS)

Jacobs, Kurt; Wiseman, Howard M.

2005-10-01

Nonlocality of the type first elucidated by Bell in 1964 is a difficult concept to explain to nonspecialists and undergraduates. We attempt to do so by showing how nonlocality can be used to solve a problem in which someone might find themselves as the result of a series of normal, even if somewhat unlikely, events. Our story is told in the style of a Sherlock Holmes mystery, and is based on Mermin's formulation of the "paradoxical" illustration of quantum nonlocality discovered by Greenberger, Horne, and Zeilinger.

The paradoxical advantages and disadvantages of natural selection: the case history of Charles Darwin.

PubMed

Lieb, J

2007-01-01

The biology of natural selection is an enduring mystery, as is the nature of Charles Darwin's chronic illness. Of the theories advanced to explain the latter, Oedipal conflicts and Chagas' disease are preeminent. Hypomania, however, propelled Darwin to the pinnacle of scientific achievement and good health, the depression that followed condemning him to intellectual stagnation, lethargy, impaired memory and concentration, and incapacitating gastrointestinal disorders. Examples of natural selection in humans are much sought after when, ironically, one need look no further than Darwin himself.

Jekyll and Hyde revisited: paradoxes in the appreciation of drug experiences and their effects on creativity.

PubMed

ten Berge, Jos

2002-01-01

Historically, states of intoxication--like dreams and madness--are seen in either one of two opposed ways. The intoxicated are either "possessed" or "under the influence" of an external agency, or revealing hidden feelings or truths (in vino veritas). Along the same lines, artists who worked during LSD, mescalin or psilocybin intoxication often refer to feelings of either being "possessed" or "liberated," a difference that can be explained partly by their expectations and partly by their evaluations, which both tend to conform to the cultural dichotomy in interpreting the irrational. Both interpretations, however, tend to obscure not only the other, but also-it is posited-the paradoxical nature of the drug experience itself. Analysis of a protocol shows that intoxication might comprise feelings of "possession" as well as "liberation" almost simultaneously, and mediumistic and some psychedelic art shows stylistic traits that can be seen as the visual expressions of both these feelings. It seems that the "demoniacal" and "psychedelic" mode come together in experiential reality, only to be divided in the cultural sphere.

Seed dispersal and seedling establishment of Sarracenia purpurea (Sarraceniaceae).

PubMed

Ellison, Aaron M; Parker, Jerelyn N

2002-06-01

Plant ecologists continue to grapple with Reid's paradox, the observation that dispersal distances of most herbs and trees are too limited to account for their recolonization of northern latitudes following glacial recession. As global climate changes and natural habitats become increasingly fragmented, understanding patterns of seed dispersal and the potential for long-distance colonization takes on new importance. We studied the dispersal and establishment of the northern pitcher plant Sarracenia purpurea, which grows commonly in isolated bogs throughout Canada and eastern North America. Median dispersal distance of S. purpurea is only 5 cm, which is insufficient to explain its occurrence throughout formerly glaciated regions of North America. Establishment probability of seeds in the field is approximately 5%, and juveniles are normally found clustered around adult plants. The large-scale population genetic structure of this species can be accounted for by rare long-distance dispersal events, but its predictable occurrence in isolated habitats requires additional explanation. Reid's paradox remains an open question, and predicting long-range colonization into fragmented habitats by species with limited dispersal ability is a novel challenge.

Sedentary behavior and sleep: paradoxical effects in association with childhood obesity.

PubMed

Must, A; Parisi, S M

2009-04-01

Sedentary behavior and sleep may be working in concert to increase the likelihood of a child becoming overweight, but in paradoxical ways. Reduction of sedentary behavior (that is, media screen time) has been extensively researched and touted as an intervention target. Inadequate sleep as a putative risk factor for obesity is only beginning to be explored. In this paper, we review the current state of research regarding these factors, and describe the existing evidence and mechanisms proposed to explain these relationships. Whereas the association between weight and sedentary behavior has been consistently shown in observational studies, effect sizes are small, and multiple mechanisms appear to be operating. Recent cross-sectional and longitudinal evidence suggests a link between short sleep duration and weight. Possible mechanisms here include direct metabolic effects as well as indirect behavioral pathways, including the presence of electronic media in children's bedrooms. Measurement issues present a challenge to both areas of research. Prospective studies that include more accurate measures of both sedentary behavior and of sleep will be needed to clarify causal pathways.

'Superluminal paradox' in wave packet propagation and its quantum mechanical resolution

NASA Astrophysics Data System (ADS)

Sokolovski, D.; Akhmatskaya, E.

2013-12-01

We analyse in detail the reshaping mechanism leading to apparently 'superluminal' advancement of a wave packet traversing a classically forbidden region. In the coordinate representation, a barrier is shown to act as an effective beamsplitter, recombining envelopes of the freely propagating pulse with various spacial shifts. Causality ensures that none of the constituent envelopes are advanced with respect to free propagation, yet the resulting pulse is advanced due to a peculiar interference effect, similar to the one responsible for 'anomalous' values which occur in Aharonov's 'weak measurements'. In the momentum space, the effect is understood as a bandwidth phenomenon, where the incident pulse probes local, rather than global, analytical properties of the transmission amplitude T(p). The advancement is achieved when T(p) mimics locally an exponential behaviour, similar to the one occurring in Berry's 'superoscillations'. Seen in a broader quantum mechanical context, the 'paradox' is but a consequence of an attempt to obtain 'which way?' information without destroying the interference between the pathways of interest. This explains, to a large extent, the failure to adequately describe tunnelling in terms of a single 'tunnelling time'.

Programming stress-induced altruistic death in engineered bacteria

PubMed Central

Tanouchi, Yu; Pai, Anand; Buchler, Nicolas E; You, Lingchong

2012-01-01

Programmed death is often associated with a bacterial stress response. This behavior appears paradoxical, as it offers no benefit to the individual. This paradox can be explained if the death is ‘altruistic': the killing of some cells can benefit the survivors through release of ‘public goods'. However, the conditions where bacterial programmed death becomes advantageous have not been unambiguously demonstrated experimentally. Here, we determined such conditions by engineering tunable, stress-induced altruistic death in the bacterium Escherichia coli. Using a mathematical model, we predicted the existence of an optimal programmed death rate that maximizes population growth under stress. We further predicted that altruistic death could generate the ‘Eagle effect', a counter-intuitive phenomenon where bacteria appear to grow better when treated with higher antibiotic concentrations. In support of these modeling insights, we experimentally demonstrated both the optimality in programmed death rate and the Eagle effect using our engineered system. Our findings fill a critical conceptual gap in the analysis of the evolution of bacterial programmed death, and have implications for a design of antibiotic treatment. PMID:23169002

The dichotomous role of H2S in cancer cell biology? Déjà vu all over again.

PubMed

Kashfi, Khosrow

2018-03-01

Nitric oxide (NO) a gaseous free radical is one of the ten smallest molecules found in nature, while hydrogen sulfide (H 2 S) is a gas that bears the pungent smell of rotten eggs. Both are toxic yet they are gasotransmitters of physiological relevance. There appears to be an uncanny resemblance between the general actions of these two gasotransmitters in health and disease. The role of NO and H 2 S in cancer has been quite perplexing, as both tumor promotion and inflammatory activities as well as anti-tumor and antiinflammatory properties have been described. These paradoxes have been explained for both gasotransmitters in terms of each having a dual or biphasic effect that is dependent on the local flux of each gas. In this review/commentary, I have discussed the major roles of NO and H 2 S in carcinogenesis, evaluating their dual nature, focusing on the enzymes that contribute to this paradox and evaluate the pros and cons of inhibiting or inducing each of these enzymes. Copyright © 2018 Elsevier Inc. All rights reserved.

The role of glucocorticoids in emotional memory reconsolidation.

PubMed

Meir Drexler, Shira; Wolf, Oliver T

2017-07-01

Glucocorticoids are secreted following exposure to stressful events. Their modulating role on memory reconsolidation, a post-retrieval process of re-stabilization, has been investigated only recently, at times with conflicting results. The goal of this review is twofold. First, to establish the modulating role of glucocorticoids on memory reconsolidation. Second, to point the potential factors and confounds that might explain the seemingly paradoxical findings. Here we review recent pharmacological studies, conducted in rodents and humans, which suggest a critical role of glucocorticoids in this post-retrieval process. In particular, the activation of glucocorticoid receptors in the amygdala and hippocampus is suggested to be involved in emotional memories reconsolidation, pointing to a similarity between post-retrieval reconsolidation and initial memory consolidation. In addition, based on the general reconsolidation literature, we suggest several factors that might play a role in determining the direction and strength of the reconsolidation effect following glucocorticoids treatment: memory-related factors, manipulation-related factors, and individual differences. We conclude that only when taking these additional factors into account can the paradox be resolved. Copyright © 2016 Elsevier Inc. All rights reserved.

Are Men Aging as Oaks and Women as Reeds? A Behavioral Hypothesis to Explain the Gender Paradox of French Centenarians

PubMed Central

Balard, Frédéric; Beluche, Isabelle; Romieu, Isabelle; Willcox, Donald Craig; Robine, Jean-Marie

2011-01-01

Since the 1990s, several studies involving French centenarians have shown a gender paradox in old age. Even if women are more numerous in old age and live longer than men, men are in better physical and cognitive health, are higher functioning, and have superior vision. If better health should lead to a longer life, why are men not living longer than women? This paper proposes a hypothesis based on the differences in the generational habitus between men and women who were born at the beginning of the 20th century. The concept of generational habitus combines the generation theory of Mannheim with the habitus concept of Bourdieu based on the observation that there exists a way of being, thinking, and doing for each generation. We hypothesized that this habitus still influences many gender-linked behaviours in old age. Men, as “oaks,” seem able to delay the afflictions of old age until a breaking point, while women, as “reeds,” seem able to survive despite an accumulation of health deficits. PMID:22175018

AGU journals should ask authors to publish results

NASA Astrophysics Data System (ADS)

Agnew, Duncan Carr

2012-07-01

The title of this Forum is meant to sound paradoxical: Isn't the publication of results what AGU journals are for? I argue that in some ways they aren't, and suggest how to fix this. Explaining this apparent paradox requires that we look at the structure of a published paper and of the research project that produced it. Any project involves many steps; for those using data to examine some problem the first step (step A) is for researchers to collect the relevant raw data. Next (step B), they analyze these data to learn about some phenomenon of interest; this analysis is very often purely computational. Then (step C), the researchers (we can now call them "the authors") arrange the results of this analysis in a way that shows the reader the evidence for the conclusions of the paper. Sometimes these results appear as a table, but more often they are shown pictorially, as, for example, a plot of a time series, a map, a correlation plot, or a cross-section. Finally (step D), the authors state the conclusions to be drawn from the results presented.

Who really pays for health insurance? The incidence of employer-provided health insurance with sticky nominal wages.

PubMed

Sommers, Benjamin D

2005-03-01

This paper addresses two seeming paradoxes in the realm of employer-provided health insurance: First, businesses consistently claim that they bear the burden of the insurance they provide for employees, despite theory and empirical evidence indicating that workers bear the full incidence. Second, benefit generosity and the percentage of premiums paid by employers have decreased in recent decades, despite the preferential tax treatment of employer-paid benefits relative to wages-trends unexplained by the standard incidence model. This paper offers a revised incidence model based on nominal wage rigidity, in an attempt to explain these paradoxes. The model predicts that when the nominal wage constraint binds, some of the burden of increasing insurance premiums will fall on firms, particularly small companies with low-wage employees. In response, firms will reduce employment, decrease benefit generosity, and require larger employee premium contributions. Using Current Population Survey data from 2000-2001, I find evidence for this kind of wage rigidity and its associated impact on the employment and premium contributions of low-wage insured workers during a period of rapid premium growth.

Successful child psychotherapy of attention deficit/hyperactive disorder: an agitated depression explanation.

PubMed

Seitler, Burton Norman

2008-09-01

Science tries to explain phenomena in ways that are demonstrable and replicable to develop logical, coherent, parsimonious, and predictive theoretical systems. Yet hyperactive children are given stimulants to "calm" them down, despite the fact that science would predict stimulants would increase hyperactivity. Bradley (1937, 1950) observed that half of the behavior-problem children to whom he administered a stimulant for one week became subdued. He called this finding paradoxical, speculating that inhibitory centers of the central nervous system were stimulated. While Bradley's assertion of a paradoxical reverse effect in children may be an empirical observation, it is not an explanation. The Attention Deficit/Hyperactive Disorder (ADHD) is inferred to exist from hyperactive behavior, which in turn, is inferred to be neurological in origin, a circular argument. An inevitable consequence of the belief in the hypothetical neurological etiology of ADHD is that children are typically given stimulants. Using the case of a seven-year old child, described as experiencing ADHD, who was treated successfully without medication as an illustration, the author provides an alternative, more parsimonious explanation of the etiology, suggesting that ADHD is related to agitated depression.

Gypsum Formation during the Messinian Salinity Crisis: an Alternative Model

NASA Astrophysics Data System (ADS)

Grothe, A.; Krijgsman, W.; Sangiorgi, F.; Vasiliev, I.; Baak, C. V.; Wolthers, M.; Stoica, M.; Reichart, G. J.; Davies, G.

2016-12-01

During the Messinian Salinity Crisis (MSC; 5.97 - 5.33 Myr ago), thick packages of evaporites (gypsum and halite) were deposited in the Mediterranean Basin. Traditionally, the occurrence of these evaporites is explained by the so-called "desiccation-model", in which evaporites are considered to result from a (partly) desiccated basin. In the last decade, it was thought that changes in the Mediterranean-Atlantic connectivity could explain the formation of gypsum. Stable isotope studies, however, show that the gypsum formed under influence of large freshwater input. Here we present new strontium isotope data from two well-dated Messinian sections in the Black and Caspian Seas. Our Sr isotope records suggest a persistent Mediterranean-Black Sea connection throughout the salinity crisis, which implies a large additional freshwater source to the Mediterranean. We claim that low saline waters from the Black Sea region are a prerequisite for gypsum formation in the Mediterranean and speculate about the mechanisms explaining this apparent paradox.

The Paradox of Restoring Native River Landscapes and Restoring Native Ecosystems in the Colorado River System

NASA Astrophysics Data System (ADS)

Schmidt, J. C.

2014-12-01

Throughout the Colorado River basin (CRb), scientists and river managers collaborate to improve native ecosystems. Native ecosystems have deteriorated due to construction of dams and diversions that alter natural flow, sediment supply, and temperature regimes, trans-basin diversions that extract large amounts of water from some segments of the channel network, and invasion of non-native animals and plants. These scientist/manager collaborations occur in large, multi-stakeholder, adaptive management programs that include the Lower Colorado River Multi-Species Conservation Program, the Glen Canyon Dam Adaptive Management Program, and the Upper Colorado River Endangered Species Recovery Program. Although a fundamental premise of native species recovery is that restoration of predam flow regimes inevitably leads to native species recovery, such is not the case in many parts of the CRb. For example, populations of the endangered humpback chub (Gila cypha) are largest in the sediment deficit, thermally altered conditions of the Colorado River downstream from Glen Canyon Dam, but these species occur in much smaller numbers in the upper CRb even though the flow regime, sediment supply, and sediment mass balance are less perturbed. Similar contrasts in the physical and biological response of restoration of predam flow regimes occurs in floodplains dominated by nonnative tamarisk (Tamarix spp.) where reestablishment of floods has the potential to exacerbate vertical accretion processes that disconnect the floodplain from the modern flow regime. A significant challenge in restoring segments of the CRb is to describe this paradox of physical and biological response to reestablishment of pre-dam flow regimes, and to clearly identify objectives of environmentally oriented river management. In many cases, understanding the nature of the perturbation to sediment mass balance caused by dams and diversions and understanding the constraints imposed by societal commitments to provide assured water supplies and hydroelectricity constrains the opportunities for rehabilitation and limits the management objectives to focus either on restoring predam physical processes or recovering native fish fauna and/or recovering native plant communities.

Residential segregation and cultural dissemination: An Axelrod-Schelling model

NASA Astrophysics Data System (ADS)

Gracia-Lázaro, C.; Lafuerza, L. F.; Floría, L. M.; Moreno, Y.

2009-10-01

In the Axelrod’s model of cultural dissemination, we consider the mobility of cultural agents through the introduction of a density of empty sites and the possibility that agents in a dissimilar neighborhood can move to them if their mean cultural similarity with the neighborhood is below some threshold. While for low values of the density of empty sites, the mobility enhances the convergence to a global culture, for high enough values of it, the dynamics can lead to the coexistence of disconnected domains of different cultures. In this regime, the increase in initial cultural diversity paradoxically increases the convergence to a dominant culture. Further increase in diversity leads to the fragmentation of the dominant culture into domains, forever changing in shape and number, as an effect of the never ending eroding activity of cultural minorities.

Frequency-dependent selection predicts patterns of radiations and biodiversity.

PubMed

Melián, Carlos J; Alonso, David; Vázquez, Diego P; Regetz, James; Allesina, Stefano

2010-08-26

Most empirical studies support a decline in speciation rates through time, although evidence for constant speciation rates also exists. Declining rates have been explained by invoking pre-existing niches, whereas constant rates have been attributed to non-adaptive processes such as sexual selection and mutation. Trends in speciation rate and the processes underlying it remain unclear, representing a critical information gap in understanding patterns of global diversity. Here we show that the temporal trend in the speciation rate can also be explained by frequency-dependent selection. We construct a frequency-dependent and DNA sequence-based model of speciation. We compare our model to empirical diversity patterns observed for cichlid fish and Darwin's finches, two classic systems for which speciation rates and richness data exist. Negative frequency-dependent selection predicts well both the declining speciation rate found in cichlid fish and explains their species richness. For groups like the Darwin's finches, in which speciation rates are constant and diversity is lower, speciation rate is better explained by a model without frequency-dependent selection. Our analysis shows that differences in diversity may be driven by incipient species abundance with frequency-dependent selection. Our results demonstrate that genetic-distance-based speciation and frequency-dependent selection are sufficient to explain the high diversity observed in natural systems and, importantly, predict decay through time in speciation rate in the absence of pre-existing niches.

Simpson's paradox: A statistician's case study.

PubMed

Chu, Kevin H; Brown, Nathan J; Pelecanos, Anita; Brown, Anthony Ft

2018-02-26

Gender equality and workforce diversity has recently been in the forefront of College discussions. Reasons for the difference between various groups may not be as they initially appeared. The results of comparing the outcome between two groups can sometimes be confounded and even reversed by an unrecognised third variable. This concept is known as Simpson's Paradox, and is illustrated here using a renowned case study on potential gender bias for acceptance to Graduate School at the University of California, Berkeley.  The investigation showed that males were 1.8 times more likely to be admitted to Graduate School than females in 1973. Initially it appeared that women were discriminated against in the selection process. However, when admissions were re-examined at individual Departments of the School, admission tended to be better for women than men in four of six Departments. This contradiction or paradox tells us that the association between admission and gender was dependent upon on Department.  The confounding effect of Department was defined by two characteristics. Firstly, a strong association between Department and admission: some Departments admitted much smaller percentages of applicants than others. Secondly, a strong association between Department and gender: females tended to apply to Departments with lower admission rates.  The explanation of differences between groups can be multifactorial. A search for possible confounders will assist in this understanding. This could apply whenever two groups initially appear to differ, but on closer analysis this difference is either unfounded, or even reversed by reference to a third, confounding variable. © 2018 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

Protective Factors as an Explanation for the "Paradox" of Black-White Differences in Heavy Drinking.

PubMed

Mulia, Nina; Ye, Yu; Karriker-Jaffe, Katherine J; Zemore, Sarah E; Jones-Webb, Rhonda

2018-04-02

African Americans are generally known to have lower heavy drinking prevalence than Whites despite often greater individual and community risk factors. While it is supposed that their protective resources explain this "paradox," studies have not explicitly examined this. Assess the contribution of protective resources to Black-White differences in heavy drinking, and (secondarily) whether protective resources operate by reducing heavy drinking and/or increasing abstinence. Using data from the 2009-2010 U.S. National Alcohol Survey (N = 3,133 Whites and 1,040 Blacks ages 18+), we applied propensity score (PS) weighting to estimate racial differences in heavy drinking and abstinence under hypothetical conditions in which Whites are similar to Blacks in: (1) age and marital status; (2) socioeconomic position and unfair treatment; (3) neighborhood socioeconomic conditions and alcohol outlet density; and (4) protective resources (proscriptive religiosity, area-level religiosity, "drier" network drinking norms and patterns, and family social support). The Black-White gap in male and female drinkers' baseline heavy drinking increased after weighting adjustments for demographics. In women, this gap was reduced after weighting on disadvantage and eliminated after adjusting for protective resources. In men, adjustment for disadvantage increased the racial gap, and protective resources reduced it. Protective resources had a stronger effect on Black-White differences in men's abstinence than heavy drinking, but similar effects on these outcomes in women. Protective resources help explain Black-White differences in men's and particularly women's heavy drinking. Future research is needed to elucidate mechanisms of action and additional factors underlying racial differences in men's heavy drinking.

Biome-scale nitrogen fixation strategies selected by climatic constraints on nitrogen cycle.

PubMed

Sheffer, Efrat; Batterman, Sarah A; Levin, Simon A; Hedin, Lars O

2015-11-23

Dinitrogen fixation by plants (in symbiosis with root bacteria) is a major source of new nitrogen for land ecosystems(1). A long-standing puzzle(2) is that trees capable of nitrogen fixation are abundant in nitrogen-rich tropical forests, but absent or restricted to early successional stages in nitrogen-poor extra-tropical forests. This biome-scale pattern presents an evolutionary paradox(3), given that the physiological cost(4) of nitrogen fixation predicts the opposite pattern: fixers should be out-competed by non-fixers in nitrogen-rich conditions, but competitively superior in nitrogen-poor soils. Here we evaluate whether this paradox can be explained by the existence of different fixation strategies in tropical versus extra-tropical trees: facultative fixers (capable of downregulating fixation(5,6) by sanctioning mutualistic bacteria(7)) are common in the tropics, whereas obligate fixers (less able to downregulate fixation) dominate at higher latitudes. Using a game-theoretic approach, we assess the ecological and evolutionary conditions under which these fixation strategies emerge, and examine their dependence on climate-driven differences in the nitrogen cycle. We show that in the tropics, transient soil nitrogen deficits following disturbance and rapid tree growth favour a facultative strategy and the coexistence of fixers and non-fixers. In contrast, sustained nitrogen deficits following disturbance in extra-tropical forests favour an obligate fixation strategy, and cause fixers to be excluded in late successional stages. We conclude that biome-scale differences in the abundance of nitrogen fixers can be explained by the interaction between individual plant strategies and climatic constraints on the nitrogen cycle over evolutionary time.

Partitioning the impact of environment and spatial structure on alpha and beta components of taxonomic, functional, and phylogenetic diversity in European ants.

PubMed

Arnan, Xavier; Cerdá, Xim; Retana, Javier

2015-01-01

We analyze the relative contribution of environmental and spatial variables to the alpha and beta components of taxonomic (TD), phylogenetic (PD), and functional (FD) diversity in ant communities found along different climate and anthropogenic disturbance gradients across western and central Europe, in order to assess the mechanisms structuring ant biodiversity. To this aim we calculated alpha and beta TD, PD, and FD for 349 ant communities, which included a total of 155 ant species; we examined 10 functional traits and phylogenetic relatedness. Variation partitioning was used to examine how much variation in ant diversity was explained by environmental and spatial variables. Autocorrelation in diversity measures and each trait's phylogenetic signal were also analyzed. We found strong autocorrelation in diversity measures. Both environmental and spatial variables significantly contributed to variation in TD, PD, and FD at both alpha and beta scales; spatial structure had the larger influence. The different facets of diversity showed similar patterns along environmental gradients. Environment explained a much larger percentage of variation in FD than in TD or PD. All traits demonstrated strong phylogenetic signals. Our results indicate that environmental filtering and dispersal limitations structure all types of diversity in ant communities. Strong dispersal limitations appear to have led to clustering of TD, PD, and FD in western and central Europe, probably because different historical and evolutionary processes generated different pools of species. Remarkably, these three facets of diversity showed parallel patterns along environmental gradients. Trait-mediated species sorting and niche conservatism appear to structure ant diversity, as evidenced by the fact that more variation was explained for FD and that all traits had strong phylogenetic signals. Since environmental variables explained much more variation in FD than in PD, functional diversity should be a better indicator of community assembly processes than phylogenetic diversity.

Experimental joint weak measurement on a photon pair as a probe of Hardy's paradox.

PubMed

Lundeen, J S; Steinberg, A M

2009-01-16

It has been proposed that the ability to perform joint weak measurements on postselected systems would allow us to study quantum paradoxes. These measurements can investigate the history of those particles that contribute to the paradoxical outcome. Here we experimentally perform weak measurements of joint (i.e., nonlocal) observables. In an implementation of Hardy's paradox, we weakly measure the locations of two photons, the subject of the conflicting statements behind the paradox. Remarkably, the resulting weak probabilities verify all of these statements but, at the same time, resolve the paradox.

Lessons from the margins of globalization: appreciating the Cuban health paradox.

PubMed

Spiegel, Jerry M; Yassi, Annalee

2004-01-01

It is widely recognized that Cuba, despite poor economic performance, has achieved and sustained health indices comparable to those in developed countries--the Cuban Paradox. There has been, however, remarkably little scholarship evaluating how this has been accomplished, especially during a period of extreme economic hardship. Cuba's exclusion from the mainstream of "globalization," moreover, allows us to gain insights into the population health impact of policies that have accompanied globalization. Cuba's experience challenges the conventional assumption that generating wealth is the fundamental precondition for improving health. As peoples around the world search for cost-effective ways to improve well-being, they might want to learn how alternative public policy approaches, such as those used in Cuba, may be effective. We therefore reviewed the literature on the health-wealth relationship in this globalizing era; then systematically examined public policy in Cuba, not only for health services (financing, vertical and horizontal integration, prevention and primary-care focus, inter-sectoral linkages, etc.) but for non-medical determinants of health as well. These included education, housing, nutrition, employment, etc. plus the community mobilization and social cohesion that the Cuban system has generated. It appears that the active implementation of public policy affecting a wide variety of health determinants explains the Cuban paradox, and that the international community can learn from Cuba's experience. The prospect for healthy public policy can thus exist within, rather than only on the margins of globalization. The importance of monitoring how Cuba sustains such policies as it faces growing challenges in this globalizing era is increasingly worth observing.

Biofeedback defaecation training for anismus.

PubMed

Lestàr, B; Penninckx, F; Kerremans, R

1991-11-01

Anismus, paradoxical external sphincter function, spastic pelvic floor syndrome, rectoanal dysnergia, abdomino-levator incoordination for abdominopelvic asychronism, are all due to paradoxical contraction of the striated sphincter apparatus during voiding and is characterised by prolonged and excessive straining at stool. Biofeedback is the treatment of choice and has to be introduced at an early stage. We present the results of an ambulatory approach based on the integration of simulated balloon defaecation with small (50 ml) as well as constant rectal sensation volume, defaecometry and anal manometry. The pathophysiology visualised by the patient's own anorectal pressure recordings on the screen of a personal computer is explained and corrected. Sixteen patients were treated and followed for at least 1 year. Manometric data were normal except for an increased minimum residual pressure and rectal compliance. Nine patients could not evacuate a 50 ml bolus initially. Simulated defaecation became possible in seven out of these nine patients when the bolus was increased up to the individual constant rectal sensation volume. Two patients could not evacuate this volume either, while defaecation was made much less laborious in the other seven patients. Paradoxical contraction was immediately corrected in 7/16 cases. Also, as an immediate, objective benefit of a single training session, improved defaecation of a 50 ml bolus was observed in 11 patients. This effect was preserved after 6 weeks in nine cases; symptomatic recurrence did not occur in these patients during follow-up. This method of defaecation training has many advantages as compared with sphincter training using EMG electrodes eventually performed in the absence of a desire to defaecate or in lying position.(ABSTRACT TRUNCATED AT 250 WORDS)

Timing paradox of stepping and falls in ageing: not so quick and quick(er) on the trigger

PubMed Central

Mille, Marie‐Laure

2016-01-01

Abstract Physiological and degenerative changes affecting human standing balance are major contributors to falls with ageing. During imbalance, stepping is a powerful protective action for preserving balance that may be voluntarily initiated in recognition of a balance threat, or be induced by an externally imposed mechanical or sensory perturbation. Paradoxically, with ageing and falls, initiation slowing of voluntary stepping is observed together with perturbation‐induced steps that are triggered as fast as or faster than for younger adults. While age‐associated changes in sensorimotor conduction, central neuronal processing and cognitive functions are linked to delayed voluntary stepping, alterations in the coupling of posture and locomotion may also prolong step triggering. It is less clear, however, how these factors may explain the accelerated triggering of induced stepping. We present a conceptual model that addresses this issue. For voluntary stepping, a disruption in the normal coupling between posture and locomotion may underlie step‐triggering delays through suppression of the locomotion network based on an estimation of the evolving mechanical state conditions for stability. During induced stepping, accelerated step initiation may represent an event‐triggering process whereby stepping is released according to the occurrence of a perturbation rather than to the specific sensorimotor information reflecting the evolving instability. In this case, errors in the parametric control of induced stepping and its effectiveness in stabilizing balance would be likely to occur. We further suggest that there is a residual adaptive capacity with ageing that could be exploited to improve paradoxical triggering and other changes in protective stepping to impact fall risk. PMID:26915664

Evaluating paradox walnut rootstocks for resistance to Armillaria root disease

USDA-ARS?s Scientific Manuscript database

The most common Juglans regia (English walnut) rootstock in California is Paradox, a hybrid between J. hindsii (Northern California black walnut) and J. regia. Unfortuntely, Paradox rootstock is highly susceptible to Armillaria root disease. The relative resistance of new clonal, Paradox rootstock...

Concentration and Diversity of Availability and Use in Information Systems: A Positive Reinforcement Model.

ERIC Educational Resources Information Center

Rousseau, Ronald

1992-01-01

Proposes a mathematical model to explain the observed concentration or diversity of nominal classes in information retrieval systems. The Lorenz Curve is discussed, Information Production Process (IPP) is explained, and a heuristic explanation of circumstances in which the model might be used is offered. (30 references) (LRW)

[Effects of environmental factors on β diversity of zooplankton community in thermal discharge seawaters near Guohua Power Plant in Xiangshan Bay, Zhejiang, China].

PubMed

Zhu, Yi-feng; Dai, Mei-xia; Zhou, Xiao-hong; Lin, Xia; Mao, Shuo-qian; Yan, Xiao-jun

2015-08-01

Zooplankton samples were seasonally collected at 10 stations in thermal discharge seawaters near Guohua Power Plant in Xiangshan Bay. The abundance data from these samples were pooled and further combined with field environmental factors, then generalised dissimilarity modelling (GDM) was used to explore the effects of environmental factors on β diversity of zooplankton community. The results showed that altogether 95 species of zooplankton belonging to 14 taxa were found. In these taxa, small zooplankton with 62.6% of abundance was the main taxa, while copepods dominated in adult groups, which abundance accounted for 35.3%. According to Whittaker's definition and additive partition, a diversity accounted for 36.3% and β diversity 63.7%. Environmental factors explained 43.8% of β diversity, and geographical distance between sampling sites had no effect on β diversity. However, there were still 19.9% of β diversity remained to be explained. After GDM fitting, there were nine environmental variables affecting zooplankton β diversity and explaining 68.8% of β diversity. The variables contributing to β diversity from high to low were seasonal water temperature, dissolved oxygen, seawater temperature increment, conductivity, suspended particulate matter, salinity, transparency, water depth and redox potential, respectively. Seasonal water temperature, dissolved oxygen and seawater temperature increment were the most important factors for driving β diversity changes, and accounted for 23.9%, 13.7% and 9.7% of absolute contribution to the interpretable portion of the β diversity, respectively. When seasonal water temperature, dissolved oxygen and seawater temperature increment were below 25 °C, greater than 5 mg · L(-1) and over 1 °C, respectively, β diversity rapidly increased with the increasing variable gradients. Furthermore, other predictors had little effect on β diversity.

Low major histocompatibility complex diversity in the Tasmanian devil predates European settlement and may explain susceptibility to disease epidemics

PubMed Central

Morris, Katrina; Austin, Jeremy J.; Belov, Katherine

2013-01-01

The Tasmanian devil (Sarcophilus harrisii) is at risk of extinction owing to the emergence of a contagious cancer known as devil facial tumour disease (DFTD). The emergence and spread of DFTD has been linked to low genetic diversity in the major histocompatibility complex (MHC). We examined MHC diversity in historical and ancient devils to determine whether loss of diversity is recent or predates European settlement in Australia. Our results reveal no additional diversity in historical Tasmanian samples. Mainland devils had common modern variants plus six new variants that are highly similar to existing alleles. We conclude that low MHC diversity has been a feature of devil populations since at least the Mid-Holocene and could explain their tumultuous history of population crashes. PMID:23221872

Revisiting Hardy's paradox: counterfactual statements, real measurements, entanglement and weak values

NASA Astrophysics Data System (ADS)

Aharonov, Yakir; Botero, Alonso; Popescu, Sandu; Reznik, Benni; Tollaksen, Jeff

2002-08-01

Hardy's paradox is revisited. Usually the paradox is dismissed on grounds of counterfactuality, i.e., because the paradoxical effects appear only when one considers results of experiments which do not actually take place. We suggest a new set of measurements in connection with Hardy's scheme, and show that when they are actually performed, they yield strange and surprising outcomes. More generally, we claim that counterfactual paradoxes point to a deeper structure inherent to quantum mechanics.

Metacommunity composition of web-spiders in a fragmented neotropical forest: relative importance of environmental and spatial effects.

PubMed

Baldissera, Ronei; Rodrigues, Everton N L; Hartz, Sandra M

2012-01-01

The distribution of beta diversity is shaped by factors linked to environmental and spatial control. The relative importance of both processes in structuring spider metacommunities has not yet been investigated in the Atlantic Forest. The variance explained by purely environmental, spatially structured environmental, and purely spatial components was compared for a metacommunity of web spiders. The study was carried out in 16 patches of Atlantic Forest in southern Brazil. Field work was done in one landscape mosaic representing a slight gradient of urbanization. Environmental variables encompassed plot- and patch-level measurements and a climatic matrix, while principal coordinates of neighbor matrices (PCNMs) acted as spatial variables. A forward selection procedure was carried out to select environmental and spatial variables influencing web-spider beta diversity. Variation partitioning was used to estimate the contribution of pure environmental and pure spatial effects and their shared influence on beta-diversity patterns, and to estimate the relative importance of selected environmental variables. Three environmental variables (bush density, land use in the surroundings of patches, and shape of patches) and two spatial variables were selected by forward selection procedures. Variation partitioning revealed that 15% of the variation of beta diversity was explained by a combination of environmental and PCNM variables. Most of this variation (12%) corresponded to pure environmental and spatially environmental structure. The data indicated that (1) spatial legacy was not important in explaining the web-spider beta diversity; (2) environmental predictors explained a significant portion of the variation in web-spider composition; (3) one-third of environmental variation was due to a spatial structure that jointly explains variation in species distributions. We were able to detect important factors related to matrix management influencing the web-spider beta-diversity patterns, which are probably linked to historical deforestation events.

Habituated Reason: Aristotle and the "Paradox of Moral Education"

ERIC Educational Resources Information Center

Kristjansson, Kristjan

2006-01-01

R.S. Peters coined the term "paradox of moral education". In this article, the author identifies two subordinate paradoxes: how habituated reason is psychologically possible and how heteronomously formed autonomy is morally/politically possible and justifiable. He sketches possible Aristotelian solutions of those paradoxes and argues that for…

Phylogenomics of the killer whale indicates ecotype divergence in sympatry.

PubMed

Moura, A E; Kenny, J G; Chaudhuri, R R; Hughes, M A; Reisinger, R R; de Bruyn, P J N; Dahlheim, M E; Hall, N; Hoelzel, A R

2015-01-01

For many highly mobile species, the marine environment presents few obvious barriers to gene flow. Even so, there is considerable diversity within and among species, referred to by some as the 'marine speciation paradox'. The recent and diverse radiation of delphinid cetaceans (dolphins) represents a good example of this. Delphinids are capable of extensive dispersion and yet many show fine-scale genetic differentiation among populations. Proposed mechanisms include the division and isolation of populations based on habitat dependence and resource specializations, and habitat release or changing dispersal corridors during glacial cycles. Here we use a phylogenomic approach to investigate the origin of differentiated sympatric populations of killer whales (Orcinus orca). Killer whales show strong specialization on prey choice in populations of stable matrifocal social groups (ecotypes), associated with genetic and phenotypic differentiation. Our data suggest evolution in sympatry among populations of resource specialists.

Safety becomes danger: dilemmas of drug-use in public space.

PubMed

Dovey, K; Fitzgerald, J; Choi, Y

2001-12-01

This paper provides a socio-spatial analysis of injecting drug-use in public space. It focuses on one urban district in Melbourne, Australia, which has become strongly identified with heroin sale and use in public space. Selling activities are camouflaged within a diverse street life while injecting sites are dispersed through a broad diversity of laneways, car parks and toilets. These injecting zones occupy liminal places which slide between categories of private and public, and which mediate complex and paradoxical relations between safety and danger. Those who inject in public space are caught in a dilemma--needing both privacy and exposure in the event of an overdose, safety from police becomes danger from an overdose. This empirical work, based on interview and spatial analysis, is presented as a basis for theorizing the socio-spatial construction of heroin use and for assessing the prospects for safe injecting.

Phylogenomics of the killer whale indicates ecotype divergence in sympatry

PubMed Central

Moura, A E; Kenny, J G; Chaudhuri, R R; Hughes, M A; Reisinger, R R; de Bruyn, P J N; Dahlheim, M E; Hall, N; Hoelzel, A R

2015-01-01

For many highly mobile species, the marine environment presents few obvious barriers to gene flow. Even so, there is considerable diversity within and among species, referred to by some as the ‘marine speciation paradox'. The recent and diverse radiation of delphinid cetaceans (dolphins) represents a good example of this. Delphinids are capable of extensive dispersion and yet many show fine-scale genetic differentiation among populations. Proposed mechanisms include the division and isolation of populations based on habitat dependence and resource specializations, and habitat release or changing dispersal corridors during glacial cycles. Here we use a phylogenomic approach to investigate the origin of differentiated sympatric populations of killer whales (Orcinus orca). Killer whales show strong specialization on prey choice in populations of stable matrifocal social groups (ecotypes), associated with genetic and phenotypic differentiation. Our data suggest evolution in sympatry among populations of resource specialists. PMID:25052415

Connections between survey calibration estimators and semiparametric models for incomplete data

PubMed Central

Lumley, Thomas; Shaw, Pamela A.; Dai, James Y.

2012-01-01

Survey calibration (or generalized raking) estimators are a standard approach to the use of auxiliary information in survey sampling, improving on the simple Horvitz–Thompson estimator. In this paper we relate the survey calibration estimators to the semiparametric incomplete-data estimators of Robins and coworkers, and to adjustment for baseline variables in a randomized trial. The development based on calibration estimators explains the ‘estimated weights’ paradox and provides useful heuristics for constructing practical estimators. We present some examples of using calibration to gain precision without making additional modelling assumptions in a variety of regression models. PMID:23833390

Paradoxical false memory for objects after brain damage.

PubMed

McTighe, Stephanie M; Cowell, Rosemary A; Winters, Boyer D; Bussey, Timothy J; Saksida, Lisa M

2010-12-03

Poor memory after brain damage is usually considered to be a result of information being lost or rendered inaccessible. It is assumed that such memory impairment must be due to the incorrect interpretation of previously encountered information as being novel. In object recognition memory experiments with rats, we found that memory impairment can take the opposite form: a tendency to treat novel experiences as familiar. This impairment could be rescued with the use of a visual-restriction procedure that reduces interference. Such a pattern of data can be explained in terms of a recent representational-hierarchical view of cognition.

Retail growth and consumer changes in a declining urban economy: Antwerp (1650-1750).

PubMed

Blondé, Bruno; van Damme, Ilja

2010-01-01

This article examines the interplay between retail changes and transformations in the material culture of Antwerp, a provincial town in the southern Netherlands. We argue that major changes in the eighteenth-century material culture and retail sector were not significantly linked to preconditions of economic growth and urbanization. The Antwerp 'retail paradox' is that of a shrinking economic horizon running parallel to material culture and retail transformations, usually connected to expanding urban economies and societies. Changing retail and consumer practices explain the growing and prospering retail sector, rather than a growing economy.

Nonthermal Hawking radiation from NUT-Taub-like black hole

NASA Astrophysics Data System (ADS)

Zhao, GuoMing; Li, PengZhang

2012-04-01

Using Damour-Ruffini method, we investigate Hawking radiation from NUT-Taub-like (NT-like) black hole. Considering the total energy conservation and the back reaction of the particle to the spacetime, we get the radiation spectrum on the black hole event horizon, which is related to the change of Bekenstein-Hawking entropy. Meanwhile, we find that the radiation is not exactly thermal, and can take out information from the black hole, which can be used to explain the information loss paradox. The result that we get satisfies the unitary theory of quantum mechanics and is consistent with the work finished before.

Paradox, reprimand and extinction in adults with mental handicap.

PubMed

Wood, V E; Chamove, A S

1991-08-01

To assess the efficacy of paradoxical directives, levels of challenging behaviour during 2 weeks of paradox, reprimand and extinction were compared with baseline levels in four adults with mental handicaps attending a day centre. Paradox was the most effective procedure for reducing the frequency and severity of challenging behaviour by an average of over 70% by the end of 2 weeks and up to 90% in certain subjects; extinction was least effective. Paradox was most effective with more defiant subjects, when staff rated treatment success as low, when improvement using extinction and reprimand was poorest, and in reducing aggressive behaviour. The present authors suggest the overjustification effect offers an explanation for the effects of paradox.

An assessment of the hypervariable domains of the 16S rRNA genes for their value in determining microbial community diversity: the paradox of traditional ecological indices.

PubMed

Mills, DeEtta K; Entry, James A; Voss, Joshua D; Gillevet, Patrick M; Mathee, Kalai

2006-09-01

Amplicon length heterogeneity PCR (LH-PCR) was investigated for its ability to distinguish between microbial community patterns from the same soil type under different land management practices. Natural sagebrush and irrigated mouldboard-ploughed soils from Idaho were queried as to which hypervariable domains, or combinations of 16S rRNA gene domains, were the best molecular markers. Using standard ecological indices to measure richness, diversity and evenness, the combination of three domains, V1, V3 and V1+V2, or the combined V1 and V3 domains were the markers that could best distinguish the undisturbed natural sagebrush communities from the mouldboard-ploughed microbial communities. Bray-Curtis similarity and multidimensional scaling were found to be better metrics to ordinate and cluster the LH-PCR community profiling data. The use/misuse of traditional ecological indices such as diversity and evenness to study microbial community profiles will remain a major point to consider when performing metagenomic studies.

A novel biological 'twin-father' temporal paradox of General Relativity in a Gödel universe - Where reproductive biology meets theoretical physics.

PubMed

Ashrafian, Hutan

2018-03-01

Several temporal paradoxes exist in physics. These include General Relativity's grandfather and ontological paradoxes and Special Relativity's Langevin-Einstein twin-paradox. General relativity paradoxes can exist due to a Gödel universe that follows Gödel's closed timelike curves solution to Einstein's field equations. A novel biological temporal paradox of General Relativity is proposed based on reproductive biology's phenomenon of heteropaternal fecundation. Herein, dizygotic twins from two different fathers are the result of concomitant fertilization during one menstrual cycle. In this case an Oedipus-like individual exposed to a Gödel closed timelike curve would sire a child during his maternal fertilization cycle. As a consequence of heteropaternal superfecundation, he would father his own dizygotic twin and would therefore generate a new class of autofraternal superfecundation, and by doing so creating a 'twin-father' temporal paradox. Copyright © 2017 Elsevier Ltd. All rights reserved.

Paradoxical response to dexamethasone and spontaneous hypocortisolism in Cushing's disease

PubMed Central

Lila, Anurag R; Sarathi, Vijaya; Bandgar, Tushar R; Shah, Nalini S

2013-01-01

Paradoxical response to dexamethasone and spontaneous development of hypocortisolism are rare features of Cushing's disease. We report a 13-year-old boy with Cushing's disease owing to a pituitary macroadenoma. On initial evaluation, he had partial suppression of serum cortisol by dexamethasone. He developed transient hypocortisolism after first adenomectomy, but the disease recurred after 1 year. Repeat evaluation showed recurrent hypercortisolism and paradoxical response to dexamethasone. He underwent second surgery and, postoperatively, hypercostisolism persisted even after 2 years of surgery. Repeat evaluations after 8 years of second surgery revealed persistent hypocortisolism despite residual tumour of same size and similar plasma adrenocorticotropic hormone (ACTH) levels. We have also shown that the paradoxical increase in serum cortisol was preceded by a paradoxical increase in ACTH. The paradoxical response persisted despite hypocortisolism. This patient with Cushing's disease had two very rare features: paradoxical response to dexamethasone and spontaneous development of hypocortisolism. PMID:23365169

Multisetting Greenberger-Horne-Zeilinger paradoxes

NASA Astrophysics Data System (ADS)

Tang, Weidong; Yu, Sixia; Oh, C. H.

2017-01-01

The Greenberger-Horne-Zeilinger (GHZ) paradox provides an all-versus-nothing test for the quantum nonlocality. In most of the GHZ paradoxes known so far each observer is allowed to measure only two alternative observables. Here we present a general construction for GHZ paradoxes in which each observer measures more than two observables given that the system is prepared in the n -qudit GHZ state. By doing so we are able to construct a multisetting GHZ paradox for the n -qubit GHZ state, with n being arbitrary, which is genuine n -partite; i.e., no GHZ paradox exists when restricted to a subset of a number of observers for a given set of Mermin observables. Our result fills up the gap of the absence of a genuine GHZ paradox for the GHZ state of an even number of qubits, especially the four-qubit GHZ state as used in GHZ's original proposal.

SOCIOECONOMIC, CULTURAL, AND BEHAVIORAL FACTORS AFFECTING HISPANIC HEALTH OUTCOMES

PubMed Central

MORALES, LEO S.; LARA, MARIELENA; KINGTON, RAYNARD S.; VALDEZ, ROBERT O.; ESCARCE, JOSÉ J.

2006-01-01

Evidence suggests that social and economic factors are important determinants of health. Yet, despite higher poverty rates, less education, and worse access to health care, health outcomes of many Hispanics living in the United States today are equal to, or better than, those of non-Hispanic whites. This paradox is described in the literature as the epidemiological paradox or Hispanic health paradox. In this paper, the authors selectively review data and research supporting the existence of the epidemiological paradox. They find substantial support for the existence of the epidemiological paradox, particularly among Mexican Americans. Census undercounts of Hispanics, misclassification of Hispanic deaths, and emigration of Hispanics do not fully account for the epidemiological paradox. Identifying protective factors underlying the epidemiological paradox, while improving access to care and the economic conditions among Hispanics, are important research and policy implications of this review. PMID:12407964

Chasing our tails: psychological, institutional and societal paradoxes in natural resource management, sustainability, and climate change in Australia.

PubMed

Browne, A L; Bishop, B J

2011-06-01

Natural Resource Management (NRM) and Ecologically Sustainable Development (ESD) have been guiding frameworks in Australia for a number of decades. Recently, NRM and ESD have become central to climate change mitigation. In this paper, we explore the psychological paradoxes that function within climate change settings, with particular attention devoted to the way that research and development reinforces these paradoxes by advocating for participatory forms of inquiry. Paradox emerges in NRM at psychological, institutional, and organisational levels. Paradoxes are also features of different forms of democracy such as neoliberal and participatory democracy. Although NRM, ESD and climate change are often conceptualised as distinct issue domains, these policy areas are fundamentally interconnected in both theory and in practice. This interconnection between these policy and research settings, reflections on paradox, and the experience of incorporating community psychology into the paradoxical settings of NRM and climate change are captured in this paper.

Direct vs. Microclimate-Driven Effects of Tree Species Diversity on Litter Decomposition in Young Subtropical Forest Stands.

PubMed

Seidelmann, Katrin N; Scherer-Lorenzen, Michael; Niklaus, Pascal A

2016-01-01

Effects of tree species diversity on decomposition can operate via a multitude of mechanism, including alterations of microclimate by the forest canopy. Studying such effects in natural settings is complicated by the fact that topography also affects microclimate and thus decomposition, so that effects of diversity are more difficult to isolate. Here, we quantified decomposition rates of standard litter in young subtropical forest stands, separating effects of canopy tree species richness and topography, and quantifying their direct and micro-climate-mediated components. Our litterbag study was carried out at two experimental sites of a biodiversity-ecosystem functioning field experiment in south-east China (BEF-China). The field sites display strong topographical heterogeneity and were planted with tree communities ranging from monocultures to mixtures of 24 native subtropical tree species. Litter bags filled with senescent leaves of three native tree species were placed from Nov. 2011 to Oct. 2012 on 134 plots along the tree species diversity gradient. Topographic features were measured for all and microclimate in a subset of plots. Stand species richness, topography and microclimate explained important fractions of the variations in litter decomposition rates, with diversity and topographic effects in part mediated by microclimatic changes. Tree stands were 2-3 years old, but nevertheless tree species diversity explained more variation (54.3%) in decomposition than topography (7.7%). Tree species richness slowed litter decomposition, an effect that slightly depended on litter species identity. A large part of the variance in decomposition was explained by tree species composition, with the presence of three tree species playing a significant role. Microclimate explained 31.4% of the variance in decomposition, and was related to lower soil moisture. Within this microclimate effect, species diversity (without composition) explained 8.9% and topography 34.4% of variance. Topography mainly affected diurnal temperature amplitudes by varying incident solar radiation.

Direct vs. Microclimate-Driven Effects of Tree Species Diversity on Litter Decomposition in Young Subtropical Forest Stands

PubMed Central

Seidelmann, Katrin N.; Scherer-Lorenzen, Michael; Niklaus, Pascal A.

2016-01-01

Effects of tree species diversity on decomposition can operate via a multitude of mechanism, including alterations of microclimate by the forest canopy. Studying such effects in natural settings is complicated by the fact that topography also affects microclimate and thus decomposition, so that effects of diversity are more difficult to isolate. Here, we quantified decomposition rates of standard litter in young subtropical forest stands, separating effects of canopy tree species richness and topography, and quantifying their direct and micro-climate-mediated components. Our litterbag study was carried out at two experimental sites of a biodiversity-ecosystem functioning field experiment in south-east China (BEF-China). The field sites display strong topographical heterogeneity and were planted with tree communities ranging from monocultures to mixtures of 24 native subtropical tree species. Litter bags filled with senescent leaves of three native tree species were placed from Nov. 2011 to Oct. 2012 on 134 plots along the tree species diversity gradient. Topographic features were measured for all and microclimate in a subset of plots. Stand species richness, topography and microclimate explained important fractions of the variations in litter decomposition rates, with diversity and topographic effects in part mediated by microclimatic changes. Tree stands were 2–3 years old, but nevertheless tree species diversity explained more variation (54.3%) in decomposition than topography (7.7%). Tree species richness slowed litter decomposition, an effect that slightly depended on litter species identity. A large part of the variance in decomposition was explained by tree species composition, with the presence of three tree species playing a significant role. Microclimate explained 31.4% of the variance in decomposition, and was related to lower soil moisture. Within this microclimate effect, species diversity (without composition) explained 8.9% and topography 34.4% of variance. Topography mainly affected diurnal temperature amplitudes by varying incident solar radiation. PMID:27490180

How Managers Use the Stockdale Paradox to Balance "the Now and the Next"

ERIC Educational Resources Information Center

Von Bergen, C. W.; Bressler, Martin S.

2017-01-01

Recent discussions of leadership paradoxes have suggested that managers who can hold seemingly opposed, yet interrelated perspectives, are more adaptive and effective. One such paradox that has received relatively little attention is the "Stockdale Paradox," named after Admiral James Stockdale, an American naval officer who was held…

Simpson's paradox in psychological science: a practical guide

PubMed Central

Kievit, Rogier A.; Frankenhuis, Willem E.; Waldorp, Lourens J.; Borsboom, Denny

2013-01-01

The direction of an association at the population-level may be reversed within the subgroups comprising that population—a striking observation called Simpson's paradox. When facing this pattern, psychologists often view it as anomalous. Here, we argue that Simpson's paradox is more common than conventionally thought, and typically results in incorrect interpretations—potentially with harmful consequences. We support this claim by reviewing results from cognitive neuroscience, behavior genetics, clinical psychology, personality psychology, educational psychology, intelligence research, and simulation studies. We show that Simpson's paradox is most likely to occur when inferences are drawn across different levels of explanation (e.g., from populations to subgroups, or subgroups to individuals). We propose a set of statistical markers indicative of the paradox, and offer psychometric solutions for dealing with the paradox when encountered—including a toolbox in R for detecting Simpson's paradox. We show that explicit modeling of situations in which the paradox might occur not only prevents incorrect interpretations of data, but also results in a deeper understanding of what data tell us about the world. PMID:23964259

Autism As a Disorder of High Intelligence

PubMed Central

Crespi, Bernard J.

2016-01-01

A suite of recent studies has reported positive genetic correlations between autism risk and measures of mental ability. These findings indicate that alleles for autism overlap broadly with alleles for high intelligence, which appears paradoxical given that autism is characterized, overall, by below-average IQ. This paradox can be resolved under the hypothesis that autism etiology commonly involves enhanced, but imbalanced, components of intelligence. This hypothesis is supported by convergent evidence showing that autism and high IQ share a diverse set of convergent correlates, including large brain size, fast brain growth, increased sensory and visual-spatial abilities, enhanced synaptic functions, increased attentional focus, high socioeconomic status, more deliberative decision-making, profession and occupational interests in engineering and physical sciences, and high levels of positive assortative mating. These findings help to provide an evolutionary basis to understanding autism risk as underlain in part by dysregulation of intelligence, a core human-specific adaptation. In turn, integration of studies on intelligence with studies of autism should provide novel insights into the neurological and genetic causes of high mental abilities, with important implications for cognitive enhancement, artificial intelligence, the relationship of autism with schizophrenia, and the treatment of both autism and intellectual disability. PMID:27445671

Race/ethnicity and all-cause mortality in US adults: revisiting the Hispanic paradox.

PubMed

Borrell, Luisa N; Lancet, Elizabeth A

2012-05-01

We examined the association between race/ethnicity and all-cause mortality risk in US adults and whether this association differs by nativity status. We used Cox proportional hazards regression to estimate all-cause mortality rates in 1997 through 2004 National Health Interview Survey respondents, relating the risk for Hispanic subgroup, non-Hispanic Black, and other non-Hispanic to non-Hispanic White adults before and after controlling for selected characteristics stratified by age and gender. We observed a Hispanic mortality advantage over non-Hispanic Whites among women that depended on nativity status: US-born Mexican Americans aged 25 to 44 years had a 90% (95% confidence interval [CI] = 0.03, 0.31) lower death rate; island- or foreign-born Cubans and other Hispanics aged 45 to 64 years were more than two times less likely to die than were their non-Hispanic White counterparts. Island- or foreign-born Puerto Rican and US-born Mexican American women aged 65 years and older exhibited at least a 25% lower rate of dying than did their non-Hispanics White counterparts. The "Hispanic paradox" may not be a static process and may change with this population growth and its increasing diversity over time.

Autism As a Disorder of High Intelligence.

PubMed

Crespi, Bernard J

2016-01-01

A suite of recent studies has reported positive genetic correlations between autism risk and measures of mental ability. These findings indicate that alleles for autism overlap broadly with alleles for high intelligence, which appears paradoxical given that autism is characterized, overall, by below-average IQ. This paradox can be resolved under the hypothesis that autism etiology commonly involves enhanced, but imbalanced, components of intelligence. This hypothesis is supported by convergent evidence showing that autism and high IQ share a diverse set of convergent correlates, including large brain size, fast brain growth, increased sensory and visual-spatial abilities, enhanced synaptic functions, increased attentional focus, high socioeconomic status, more deliberative decision-making, profession and occupational interests in engineering and physical sciences, and high levels of positive assortative mating. These findings help to provide an evolutionary basis to understanding autism risk as underlain in part by dysregulation of intelligence, a core human-specific adaptation. In turn, integration of studies on intelligence with studies of autism should provide novel insights into the neurological and genetic causes of high mental abilities, with important implications for cognitive enhancement, artificial intelligence, the relationship of autism with schizophrenia, and the treatment of both autism and intellectual disability.

Exploring Molecular Mechanisms of Paradoxical Activation in the BRAF Kinase Dimers: Atomistic Simulations of Conformational Dynamics and Modeling of Allosteric Communication Networks and Signaling Pathways

PubMed Central

Tse, Amanda; Verkhivker, Gennady M.

2016-01-01

The recent studies have revealed that most BRAF inhibitors can paradoxically induce kinase activation by promoting dimerization and enzyme transactivation. Despite rapidly growing number of structural and functional studies about the BRAF dimer complexes, the molecular basis of paradoxical activation phenomenon is poorly understood and remains largely hypothetical. In this work, we have explored the relationships between inhibitor binding, protein dynamics and allosteric signaling in the BRAF dimers using a network-centric approach. Using this theoretical framework, we have combined molecular dynamics simulations with coevolutionary analysis and modeling of the residue interaction networks to determine molecular determinants of paradoxical activation. We have investigated functional effects produced by paradox inducer inhibitors PLX4720, Dabrafenib, Vemurafenib and a paradox breaker inhibitor PLX7904. Functional dynamics and binding free energy analyses of the BRAF dimer complexes have suggested that negative cooperativity effect and dimer-promoting potential of the inhibitors could be important drivers of paradoxical activation. We have introduced a protein structure network model in which coevolutionary residue dependencies and dynamic maps of residue correlations are integrated in the construction and analysis of the residue interaction networks. The results have shown that coevolutionary residues in the BRAF structures could assemble into independent structural modules and form a global interaction network that may promote dimerization. We have also found that BRAF inhibitors could modulate centrality and communication propensities of global mediating centers in the residue interaction networks. By simulating allosteric communication pathways in the BRAF structures, we have determined that paradox inducer and breaker inhibitors may activate specific signaling routes that correlate with the extent of paradoxical activation. While paradox inducer inhibitors may facilitate a rapid and efficient communication via an optimal single pathway, the paradox breaker may induce a broader ensemble of suboptimal and less efficient communication routes. The central finding of our study is that paradox breaker PLX7904 could mimic structural, dynamic and network features of the inactive BRAF-WT monomer that may be required for evading paradoxical activation. The results of this study rationalize the existing structure-functional experiments by offering a network-centric rationale of the paradoxical activation phenomenon. We argue that BRAF inhibitors that amplify dynamic features of the inactive BRAF-WT monomer and intervene with the allosteric interaction networks may serve as effective paradox breakers in cellular environment. PMID:27861609

Oscillatory activity in the basal ganglia and deep brain stimulation.

PubMed

Guridi, Jorge; Alegre, Manuel

2017-01-01

Over the past 10 years, research into the neurophysiology of the basal ganglia has provided new insights into the pathophysiology of movement disorders. The presence of pathological oscillations at specific frequencies has been linked to different signs and symptoms in PD and dystonia, suggesting a new model to explain basal ganglia dysfunction. These advances occurred in parallel with improvements in imaging and neurosurgical techniques, both of which having facilitated the more widespread use of DBS to modulate dysfunctional circuits. High-frequency stimulation is thought to disrupt pathological activity in the motor cortex/basal ganglia network; however, it is not easy to explain all of its effects based only on changes in network oscillations. In this viewpoint, we suggest that a return to classic anatomical concepts might help to understand some apparently paradoxical findings. © 2016 International Parkinson and Movement Disorder Society. © 2016 International Parkinson and Movement Disorder Society.

Gas Retention in a Heated Plastic Bonded Explosive (LX-14).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hobbs, Michael L.; Kaneshige, Michael J.; Erikson, William W.

In prior work, we found that the nitroplasticizer in the plastic bonded explosive PBX 9501 played a crucial role in cookoff, especially when predicting response in larger systems [1]. We have recently completed experiments with a similar explosive, LX-14, that has a relatively nonreactive binder. We expected the ignition times for LX-14 to be longer than PBX 9501 since PBX 9501 has a more reactive binder. However, our experiments show the opposite trend. This paradox can be explained by retention of reactive gases within the interior of LX-14 by the higher strength binder resulting in faster ignition times. In contrast,more » the binder in PBX 9501 melts at low temperatures and does not retain decomposition gases as well as the LX-14 binder. Retention of reactive gases in LX-14 may also explain the more violent response in oblique impact tests [2] when compared to PBX 9501.« less

Collective Behavior of Brain Tumor Cells: the Role of Hypoxia

NASA Astrophysics Data System (ADS)

Khain, Evgeniy; Katakowski, Mark; Hopkins, Scott; Szalad, Alexandra; Zheng, Xuguang; Jiang, Feng; Chopp, Michael

2013-03-01

We consider emergent collective behavior of a multicellular biological system. Specifically we investigate the role of hypoxia (lack of oxygen) in migration of brain tumor cells. We performed two series of cell migration experiments. The first set of experiments was performed in a typical wound healing geometry: cells were placed on a substrate, and a scratch was done. In the second set of experiments, cell migration away from a tumor spheroid was investigated. Experiments show a controversy: cells under normal and hypoxic conditions have migrated the same distance in the ``spheroid'' experiment, while in the ``scratch'' experiment cells under normal conditions migrated much faster than under hypoxic conditions. To explain this paradox, we formulate a discrete stochastic model for cell dynamics. The theoretical model explains our experimental observations and suggests that hypoxia decreases both the motility of cells and the strength of cell-cell adhesion. The theoretical predictions were further verified in independent experiments.

Does an immigrant health paradox exist among Asian Americans? Associations of nativity and occupational class with self-rated health and mental disorders.

PubMed

John, Dolly A; de Castro, A B; Martin, Diane P; Duran, Bonnie; Takeuchi, David T

2012-12-01

A robust socioeconomic gradient in health is well-documented, with higher socioeconomic status (SES) associated with better health across the SES spectrum. However, recent studies of U.S. racial/ethnic minorities and immigrants show complex SES-health patterns (e.g., flat gradients), with individuals of low SES having similar or better health than their richer, U.S.-born and more acculturated counterparts, a so-called "epidemiological paradox" or "immigrant health paradox". To examine whether this exists among Asian Americans, we investigate how nativity and occupational class (white-collar, blue-collar, service, unemployed) are associated with subjective health (self-rated physical health, self-rated mental health) and 12-month DSM-IV mental disorders (any mental disorder, anxiety, depression). We analyzed data from 1530 Asian respondents to the 2002-2003 National Latino and Asian American Study in the labor force using hierarchical multivariate logistic regression models controlling for confounders, subjective social status (SSS), material and psychosocial factors theorized to explain health inequalities. Compared to U.S.-born Asians, immigrants had worse socioeconomic profiles, and controlling for age and gender, increased odds for reporting fair/poor mental health and decreased odds for any DSM-IV mental disorder and anxiety. No strong occupational class-health gradients were found. The foreign-born health-protective effect persisted after controlling for SSS but became nonsignificant after controlling for material and psychosocial factors. Speaking fair/poor English was strongly associated with all outcomes. Material and psychosocial factors were associated with some outcomes--perceived financial need with subjective health, uninsurance with self-rated mental health and depression, social support, discrimination and acculturative stress with all or most DSM-IV outcomes. Our findings caution against using terms like "immigrant health paradox" which oversimplify complex patterns and mask negative outcomes among underserved sub-groups (e.g., speaking fair/poor English, experiencing acculturative stress). We discuss implications for better measurement of SES and health given the absence of a gradient and seemingly contradictory finding of nativity-related differences in self-rated health and DSM-IV mental disorders. Copyright © 2012 Elsevier Ltd. All rights reserved.

Geological sulfur isotopes indicate elevated OCS in the Archean atmosphere, solving faint young sun paradox.

PubMed

Ueno, Yuichiro; Johnson, Matthew S; Danielache, Sebastian O; Eskebjerg, Carsten; Pandey, Antra; Yoshida, Naohiro

2009-09-01

Distributions of sulfur isotopes in geological samples would provide a record of atmospheric composition if the mechanism producing the isotope effects could be described quantitatively. We determined the UV absorption spectra of 32SO2, 33SO2, and 34SO2 and use them to interpret the geological record. The calculated isotopic fractionation factors for SO2 photolysis give mass independent distributions that are highly sensitive to the atmospheric concentrations of O2, O3, CO2, H2O, CS2, NH3, N2O, H2S, OCS, and SO2 itself. Various UV-shielding scenarios are considered and we conclude that the negative Delta33S observed in the Archean sulfate deposits can only be explained by OCS shielding. Of relevant Archean gases, OCS has the unique ability to prevent SO2 photolysis by sunlight at lambda >202 nm. Scenarios run using a photochemical box model show that ppm levels of OCS will accumulate in a CO-rich, reducing Archean atmosphere. The radiative forcing, due to this level of OCS, is able to resolve the faint young sun paradox. Further, the decline of atmospheric OCS may have caused the late Archean glaciation.

Differences in cognitive functions between cytomegalovirus-infected and cytomegalovirus-free university students: a case control study.

PubMed

Chvátalová, Veronika; Šebánková, Blanka; Hrbáčková, Hana; Tureček, Petr; Flegr, Jaroslav

2018-03-28

Cytomegalovirus (CMV) is the herpetic virus, which infects 45-100% people worldwide. Many reports suggest that CMV could impair cognitive functions of infected subjects. Here we searched for indices of effects of CMV on infected subjects' intelligence and knowledge. The Intelligence Structure Test I-S-T 2000 R was used to compare IQ of 148 CMV-infected and 135 CMV-free university students. Infected students expressed higher intelligence. Paradoxically, their IQ decreased with decreasing concentration of anti-CMV antibodies, which can be used, statistically, as a proxy of the time passed from the moment of infection in young subjects when the age of subjects is statistically controlled. The paradox of seemingly higher intelligence of CMV infected subjects could be explained by the presence of the subpopulation of about 5-10% CMV-positive individuals in the population of "CMV-negative students". These false negative subjects had probably not only the oldest infections and therefore the lowest concentration of anamnestic antibodies, but also the lowest intelligence among the infected students. Prevalence of CMV infection in all countries is very high, approaching sometimes 90%. Therefore, the total impact of CMV on human intelligence may be large.

Influence of sleep deprivation and auditory intensity on reaction time and response force.

PubMed

Włodarczyk, Dariusz; Jaśkowski, Piotr; Nowik, Agnieszka

2002-06-01

Arousal and activation are two variables supposed to underlie change in response force. This study was undertaken to explain these roles, specifically, for strong auditory stimuli and sleep deficit. Loud auditory stimuli can evoke phasic overarousal whereas sleep deficit leads to general underarousal. Moreover, Van der Molen and Keuss (1979, 1981) showed that paradoxically long reaction times occurred with extremely strong auditory stimuli when the task was difficult, e.g., choice reaction or Simon paradigm. It was argued that this paradoxical behavior related to reaction time is due to active disconnecting of the coupling between arousal and activation to prevent false responses. If so, we predicted that for extremely loud stimuli and for difficult tasks, the lengthening of reaction time should be associated with reduction of response force. The effects of loudness and sleep deficit on response time and force were investigated in three different tasks: simple response, choice response, and Simon paradigm. According to our expectation, we found a detrimental effect of sleep deficit on reaction time and on response force. In contrast to Van der Molen and Keuss, we found no increase in reaction time for loud stimuli (up to 110 dB) even on the Simon task.

Thermodynamic approach to the paradox of diamond formation with simultaneous graphite etching in the low pressure synthesis of diamond

NASA Astrophysics Data System (ADS)

Hwang, Nong M.; Yoon, Duk Y.

1996-03-01

In spite of the critical handicap from the thermodynamic point of view, the atomic hydrogen hypothesis is strongly supported by experimental observations of diamond deposition with simultaneous graphite etching. Thermodynamic analysis of the CH system showed that at ˜ 1500 K, carbon solubility in the gas phase is minimal and thus, the equilibrium fraction of solid carbon is maximal. Depending on whether gas phase nucleation takes place or not, the driving force is for deposition or for etching of solid carbon below ˜ 1500 K for the input gas of the typical mixture of 1% CH 499% H 2. The previous observation of etching of the graphite substrate is not expected unless solid carbon precipitated in the gas phase. By rigorous thermodynamic analysis of the previous experimental observations of diamond deposition with simultaneous graphite etching, we suggested that the previous implicit assumption that diamond deposits by an atomic unit should be the weakest point leading to the thermodynamic paradox. The experimental observations could be successfully explained without violating thermodynamics by assuming that the diamond phase had nucleated in the gas phase as fine clusters.

An increased frequency of patent foramen ovale in patients with transient global amnesia. Analysis of 53 consecutive patients.

PubMed

Klötzsch, C; Sliwka, U; Berlit, P; Noth, J

1996-06-01

Alerted by the number of patients with transient global amnesia (TGA) in whom Valsalvalike activities immediately preceded the onset of TGA, we have investigated the frequency of patent foramen ovale (PFO) as the prerequisite for paradoxical embolism. Case series with comparison to a control group. Hospitalized and ambulatory patients at the neurological departments of the Alfried Krupp Hospital, Essen, Germany, and the Rheinisch-Westfälische-Technische Hochschule, Aachen, Germany. Fifty-three consecutive patients with TGA were evaluated by the 2 centers between 1988 and 1995. Using contrast transcranial Doppler sonography we have observed a PFO in 55% of the patients with TGA, compared with 27% of a control group of 100 patients. This difference was statistically significant (P < .01). Twenty-five patients with TGA (47%), 15 of them with a proven PFO, reported a precipitating activity, such as the lifting of heavy weights, immediately before the TGA occurred. In addition to other pathological mechanisms, paradoxical embolism with temporobasal ischemia could possibly play a role in the clinical syndrome of TGA. This hypothesis could explain the frequent observation of preceding Valsalvalike activities in patients with TGA.

Selection on skewed characters and the paradox of stasis

PubMed Central

Bonamour, Suzanne; Teplitsky, Céline; Charmantier, Anne; Crochet, Pierre-André; Chevin, Luis-Miguel

2018-01-01

Observed phenotypic responses to selection in the wild often differ from predictions based on measurements of selection and genetic variance. An overlooked hypothesis to explain this paradox of stasis is that a skewed phenotypic distribution affects natural selection and evolution. We show through mathematical modelling that, when a trait selected for an optimum phenotype has a skewed distribution, directional selection is detected even at evolutionary equilibrium, where it causes no change in the mean phenotype. When environmental effects are skewed, Lande and Arnold’s (1983) directional gradient is in the direction opposite to the skew. In contrast, skewed breeding values can displace the mean phenotype from the optimum, causing directional selection in the direction of the skew. These effects can be partitioned out using alternative selection estimates based on average derivatives of individual relative fitness, or additive genetic covariances between relative fitness and trait (Robertson-Price identity). We assess the validity of these predictions using simulations of selection estimation under moderate samples size. Ecologically relevant traits may commonly have skewed distributions, as we here exemplify with avian laying date – repeatedly described as more evolutionarily stable than expected –, so this skewness should be accounted for when investigating evolutionary dynamics in the wild. PMID:28921508

The Effect of Life History on Retroviral Genome Invasions

PubMed Central

Kanda, Ravinder K.; Coulson, Tim

2015-01-01

Endogenous retroviruses (ERV), or the remnants of past retroviral infections that are no longer active, are found in the genomes of most vertebrates, typically constituting approximately 10% of the genome. In some vertebrates, particularly in shorter-lived species like rodents, it is not unusual to find active endogenous retroviruses. In longer-lived species, including humans where substantial effort has been invested in searching for active ERVs, it is unusual to find them; to date none have been found in humans. Presumably the chance of detecting an active ERV infection is a function of the length of an ERV epidemic. Intuitively, given that ERVs or signatures of past ERV infections are passed from parents to offspring, we might expect to detect more active ERVs in species with longer generation times, as it should take more years for an infection to run its course in longer than in shorter lived species. This means the observation of more active ERV infections in shorter compared to longer-lived species is paradoxical. We explore this paradox using a modeling approach to investigate factors that influence ERV epidemic length. Our simple epidemiological model may explain why we find evidence of active ERV infections in shorter rather than longer-lived species. PMID:25692467

Exploring risk factors in Latino cardiovascular disease: the role of education, nativity, and gender.

PubMed

Dinwiddie, Gniesha Y; Zambrana, Ruth E; Garza, Mary A

2014-09-01

We examined 3 cardiovascular disease risk factors by nativity and gender, evaluating evidence for education and health behaviors in explaining the "Hispanic Health Paradox." We analyzed 2001-2008 National Health and Nutrition Examination Survey data for adults (n = 6032) to compare hypertension, high waist circumference, and diabetes for US- and foreign-born Mexican men and women. We controlled for age, depression, and health insurance. Cardiovascular disease risk factors differed by education, nativity, and gender. Higher education was associated with higher odds of hypertension and high waist circumference for men and women regardless of nativity. As education increased, the odds of diabetes increased for US-born women, showing a gradient for this population. Finally, foreign-born Mexican women with 5 to 19 years in the United States conferred the highest odds of having diabetes, whereas foreign-born men with less than 5 years in the United States had the lowest odds for high waist circumference and presence of diabetes. Results contest assumptions of the Hispanic Health Paradox and suggest new approaches. New research can yield accurate information to ensure the development of appropriate interventions, decreasing health disparities endemic to a subgroup of Latinos.

A conceptual model for the growth, persistence, and blooming behavior of the benthic mat-forming diatom Didymosphenia geminata (Invited)

NASA Astrophysics Data System (ADS)

Cullis, J. D.; Gillis, C.; Bothwell, M.; Kilroy, C.; Packman, A. I.; Hassan, M. A.

2010-12-01

The nuisance diatom Didymosphenia geminata (didymo) presents an ecological paradox. How can this benthic algae produce such large amounts of biomass in cold, fast flowing, low nutrient streams? The aim of this paper is to present a conceptual model for the growth, persistence, and blooming behavior of this benthic mat-forming diatom that may help to explain this paradox. The conceptual model highlights the importance of distinguishing between mat thickness and cell growth. It presents evidence gathered from a range of existing studies around the world to support the proposed relationship between growth and light, nutrients and temperature as well as the importance of flood events and bed disturbance in mat removal. It is anticipated that this conceptual model will not only help in identifying the key controlling variables and set a framework for future studies but also support the future management of this nuisance algae. Summary of the conceptual model for didymo growth showing the proposed relationships for the growth of cells and mats with nutrients, radiation and water temperature and the dependence of removal on bed shear stress and the potential for physical bed disturbance.

Paradoxical psychometric functions (“swan functions”) are explained by dilution masking in four stimulus dimensions

PubMed Central

Baker, Daniel H.; Meese, Tim S.; Georgeson, Mark A.

2013-01-01

The visual system dissects the retinal image into millions of local analyses along numerous visual dimensions. However, our perceptions of the world are not fragmentary, so further processes must be involved in stitching it all back together. Simply summing up the responses would not work because this would convey an increase in image contrast with an increase in the number of mechanisms stimulated. Here, we consider a generic model of signal combination and counter-suppression designed to address this problem. The model is derived and tested for simple stimulus pairings (e.g. A + B), but is readily extended over multiple analysers. The model can account for nonlinear contrast transduction, dilution masking, and signal combination at threshold and above. It also predicts nonmonotonic psychometric functions where sensitivity to signal A in the presence of pedestal B first declines with increasing signal strength (paradoxically dropping below 50% correct in two-interval forced choice), but then rises back up again, producing a contour that follows the wings and neck of a swan. We looked for and found these “swan” functions in four different stimulus dimensions (ocularity, space, orientation, and time), providing some support for our proposal. PMID:23799185

Excessive Weight Favours Skin Physiology - Up to a Point: Another Expression of the Obesity Paradox.

PubMed

Monteiro Rodrigues, Luís Monteiro; Palma, Lídia; Santos, Osvaldo; Almeida, Maria Angélica; Bujan, Julia; Tavares, Liliana

2017-01-01

Recently classified as an epidemic by the WHO, obesity (as well as the state of being overweight) clearly affects significant populations across all ages. The relationship between obesity and some diseases (e.g. cardiovascular ones) is known, although many paradoxes remain to be explained. Very little information is available, however, regarding its impact on skin physiology and skin disease. This study aims to examine the influence of excessive weight on epidermal hydration and transepidermal water loss, key variables of skin water balance and skin biomechanics. A convenience sample of 89 healthy female volunteers was selected and divided into 4 groups, according to their BMI (body mass index), as normal (control), overweight, obese (I and II), and morbid. Skin physiology was quantitatively assessed in all individuals in 4 anatomical areas using non-invasive biometrical analysis by reference instrumentation. Descriptive and comparative statistics were applied, adopting a confidence level of 95%. A non-linear alteration for all variables was detected as a function of BMI. Results suggest that excessive weight might favour skin performance within certain limits, reflecting a particular adaptation of the skin to the weight gain and body contour. © 2017 S. Karger AG, Basel.

Geological sulfur isotopes indicate elevated OCS in the Archean atmosphere, solving faint young sun paradox

PubMed Central

Ueno, Yuichiro; Johnson, Matthew S.; Danielache, Sebastian O.; Eskebjerg, Carsten; Pandey, Antra; Yoshida, Naohiro

2009-01-01

Distributions of sulfur isotopes in geological samples would provide a record of atmospheric composition if the mechanism producing the isotope effects could be described quantitatively. We determined the UV absorption spectra of 32SO2, 33SO2, and 34SO2 and use them to interpret the geological record. The calculated isotopic fractionation factors for SO2 photolysis give mass independent distributions that are highly sensitive to the atmospheric concentrations of O2, O3, CO2, H2O, CS2, NH3, N2O, H2S, OCS, and SO2 itself. Various UV-shielding scenarios are considered and we conclude that the negative Δ33S observed in the Archean sulfate deposits can only be explained by OCS shielding. Of relevant Archean gases, OCS has the unique ability to prevent SO2 photolysis by sunlight at λ >202 nm. Scenarios run using a photochemical box model show that ppm levels of OCS will accumulate in a CO-rich, reducing Archean atmosphere. The radiative forcing, due to this level of OCS, is able to resolve the faint young sun paradox. Further, the decline of atmospheric OCS may have caused the late Archean glaciation. PMID:19706450

Filtering the reality: functional dissociation of lateral and medial pain systems during sleep in humans.

PubMed

Bastuji, Hélène; Mazza, Stéphanie; Perchet, Caroline; Frot, Maud; Mauguière, François; Magnin, Michel; Garcia-Larrea, Luis

2012-11-01

Behavioral reactions to sensory stimuli during sleep are scarce despite preservation of sizeable cortical responses. To further understand such dissociation, we recorded intracortical field potentials to painful laser pulses in humans during waking and all-night sleep. Recordings were obtained from the three cortical structures receiving 95% of the spinothalamic cortical input in primates, namely the parietal operculum, posterior insula, and mid-anterior cingulate cortex. The dynamics of responses during sleep differed among cortical sites. In sleep Stage 2, evoked potential amplitudes were similarly attenuated relative to waking in all three cortical regions. During paradoxical, or rapid eye movements (REM), sleep, opercular and insular potentials remained stable in comparison with Stage 2, whereas the responses from mid-anterior cingulate abated drastically, and decreasing below background noise in half of the subjects. Thus, while the lateral operculo-insular system subserving sensory analysis of somatic stimuli remained active during paradoxical-REM sleep, mid-anterior cingulate processes related to orienting and avoidance behavior were suppressed. Dissociation between sensory and orienting-motor networks might explain why nociceptive stimuli can be either neglected or incorporated into dreams without awakening the subject. Copyright © 2011 Wiley Periodicals, Inc.

Can signalling theory and the semaphoric nature of information systems explain clinicians' ambivalence to informatics?

PubMed

Meyer, Derek; Cox, Benita

2010-01-01

Investment in information systems has traditionally been justified in terms of productivity or value-added gain. From this point of view the slow rate of adoption of IT in the healthcare sector appears paradoxical because the rapid increase in medical costs has created an urgent need for productivity improvements. Spence's market signal theory may explain why some information system investment decisions are made and may, in part, explains the reluctance of clinicians to embrace informatics. Case studies are presented where we argue that information system investment was made primarily to send a market signal. We call information systems that are used primarily to send a market signal, semaphoric information systems. Characteristics of semaphoric information systems are presented. It is postulated that the therapeutic relationship between doctor and patient is central to current models of healthcare, and that the semaphoric 'message' of the current generation of IT systems may be detrimental to this relationship. This suggests that clinicians will continue to be reluctant to embrace information systems until information systems are developed that can send signals that enhance the doctor-patient relationship.

Why genes don't count (for racial differences in health).

PubMed Central

Goodman, A H

2000-01-01

There is a paradoxical relationship between "race" and genetics. Whereas genetic data were first used to prove the validity of race, since the early 1970s they have been used to illustrate the invalidity of biological races. Indeed, race does not account for human genetic variation, which is continuous, complexly structured, constantly changing, and predominantly within "races." Despite the disproof of race-as-biology, genetic variation continues to be used to explain racial differences. Such explanations require the acceptance of 2 disproved assumptions: that genetic variation explains variation in disease and that genetic variation explains racial variation in disease. While the former is a form of geneticization, the notion that genes are the primary determinants of biology and behavior, the latter represents a form of racialization, an exaggeration of the salience of race. Using race as a proxy for genetic differences limits understandings of the complex interactions among political-economic processes, lived experiences, and human biologies. By moving beyond studies of racialized genetics, we can clarify the processes by which varied and interwoven forms of racialization and racism affect individuals "under the skin." PMID:11076233

Why genes don't count (for racial differences in health).

PubMed

Goodman, A H

2000-11-01

There is a paradoxical relationship between "race" and genetics. Whereas genetic data were first used to prove the validity of race, since the early 1970s they have been used to illustrate the invalidity of biological races. Indeed, race does not account for human genetic variation, which is continuous, complexly structured, constantly changing, and predominantly within "races." Despite the disproof of race-as-biology, genetic variation continues to be used to explain racial differences. Such explanations require the acceptance of 2 disproved assumptions: that genetic variation explains variation in disease and that genetic variation explains racial variation in disease. While the former is a form of geneticization, the notion that genes are the primary determinants of biology and behavior, the latter represents a form of racialization, an exaggeration of the salience of race. Using race as a proxy for genetic differences limits understandings of the complex interactions among political-economic processes, lived experiences, and human biologies. By moving beyond studies of racialized genetics, we can clarify the processes by which varied and interwoven forms of racialization and racism affect individuals "under the skin."

Entrepreneurial Regions: Do Macro-Psychological Cultural Characteristics of Regions Help Solve the "Knowledge Paradox" of Economics?

PubMed

Obschonka, Martin; Stuetzer, Michael; Gosling, Samuel D; Rentfrow, Peter J; Lamb, Michael E; Potter, Jeff; Audretsch, David B

2015-01-01

In recent years, modern economies have shifted away from being based on physical capital and towards being based on new knowledge (e.g., new ideas and inventions). Consequently, contemporary economic theorizing and key public policies have been based on the assumption that resources for generating knowledge (e.g., education, diversity of industries) are essential for regional economic vitality. However, policy makers and scholars have discovered that, contrary to expectations, the mere presence of, and investments in, new knowledge does not guarantee a high level of regional economic performance (e.g., high entrepreneurship rates). To date, this "knowledge paradox" has resisted resolution. We take an interdisciplinary perspective to offer a new explanation, hypothesizing that "hidden" regional culture differences serve as a crucial factor that is missing from conventional economic analyses and public policy strategies. Focusing on entrepreneurial activity, we hypothesize that the statistical relation between knowledge resources and entrepreneurial vitality (i.e., high entrepreneurship rates) in a region will depend on "hidden" regional differences in entrepreneurial culture. To capture such "hidden" regional differences, we derive measures of entrepreneurship-prone culture from two large personality datasets from the United States (N = 935,858) and Great Britain (N = 417,217). In both countries, the findings were consistent with the knowledge-culture-interaction hypothesis. A series of nine additional robustness checks underscored the robustness of these results. Naturally, these purely correlational findings cannot provide direct evidence for causal processes, but the results nonetheless yield a remarkably consistent and robust picture in the two countries. In doing so, the findings raise the idea of regional culture serving as a new causal candidate, potentially driving the knowledge paradox; such an explanation would be consistent with research on the psychological characteristics of entrepreneurs.

Turnover of plant lineages shapes herbivore phylogenetic beta diversity along ecological gradients.

PubMed

Pellissier, Loïc; Ndiribe, Charlotte; Dubuis, Anne; Pradervand, Jean-Nicolas; Salamin, Nicolas; Guisan, Antoine; Rasmann, Sergio

2013-05-01

Understanding drivers of biodiversity patterns is of prime importance in this era of severe environmental crisis. More diverse plant communities have been postulated to represent a larger functional trait-space, more likely to sustain a diverse assembly of herbivore species. Here, we expand this hypothesis to integrate environmental, functional and phylogenetic variation of plant communities as factors explaining the diversity of lepidopteran assemblages along elevation gradients in the Swiss Western Alps. According to expectations, we found that the association between butterflies and their host plants is highly phylogenetically structured. Multiple regression analyses showed the combined effect of climate, functional traits and phylogenetic diversity in structuring butterfly communities. Furthermore, we provide the first evidence that plant phylogenetic beta diversity is the major driver explaining butterfly phylogenetic beta diversity. Along ecological gradients, the bottom up control of herbivore diversity is thus driven by phylogenetically structured turnover of plant traits as well as environmental variables. © 2013 Blackwell Publishing Ltd/CNRS.

Regional-scale drivers of marine nematode distribution in Southern Ocean continental shelf sediments

NASA Astrophysics Data System (ADS)

Hauquier, Freija; Verleyen, Elie; Tytgat, Bjorn; Vanreusel, Ann

2018-07-01

Many marine meiofauna taxa seem to possess cosmopolitan species distributions, despite their endobenthic lifestyle and restricted long-distance dispersal capacities. In light of this paradox we used a metacommunity framework to study spatial turnover in free-living nematode distribution and assess the importance of local environmental conditions in explaining differences between communities in surface and subsurface sediments of the Southern Ocean continental shelf. We analysed nematode community structure in two sediment layers (0-3 cm and 3-5 cm) of locations maximum 2400 km apart. We first focused on a subset of locations to evaluate whether the genus level is sufficiently taxonomically fine-grained to study large-scale patterns in nematode community structure. We subsequently used redundancy and variation partitioning analyses to quantify the unique and combined effects of local environmental conditions and spatial descriptors on genus-level community composition. Macroecological patterns in community structure were highly congruent at the genus and species level. Nematode community composition was highly divergent between both depth strata, likely as a result of local abiotic conditions. Variation in community structure between the different regions largely stemmed from turnover (i.e. genus/species replacement) rather than nestedness (i.e. genus/species loss). The level of turnover among communities increased with geographic distance and was more pronounced in subsurface layers compared to surface sediments. Variation partitioning analysis revealed that both environmental and spatial predictors significantly explained variation in community structure. Moreover, the shared fraction of both sets of variables was high, which suggested a substantial amount of spatially structured environmental variation. Additionally, the effect of space independent of environment was much higher than the effect of environment independent of space, which shows the importance of including spatial descriptors in meiofauna and nematode community ecology. Large-scale assessment of free-living nematode diversity and abundance in the Southern Ocean shelf zone revealed strong horizontal and vertical spatial structuring in response to local environmental conditions, in combination with (most likely) dispersal limitation.

The landscape of sex-differential transcriptome and its consequent selection in human adults.

PubMed

Gershoni, Moran; Pietrokovski, Shmuel

2017-02-07

The prevalence of several human morbid phenotypes is sometimes much higher than intuitively expected. This can directly arise from the presence of two sexes, male and female, in one species. Men and women have almost identical genomes but are distinctly dimorphic, with dissimilar disease susceptibilities. Sexually dimorphic traits mainly result from differential expression of genes present in both sexes. Such genes can be subject to different, and even opposing, selection constraints in the two sexes. This can impact human evolution by differential selection on mutations with dissimilar effects on the two sexes. We comprehensively mapped human sex-differential genetic architecture across 53 tissues. Analyzing available RNA-sequencing data from 544 adults revealed thousands of genes differentially expressed in the reproductive tracts and tissues common to both sexes. Sex-differential genes are related to various biological systems, and suggest new insights into the pathophysiology of diverse human diseases. We also identified a significant association between sex-specific gene transcription and reduced selection efficiency and accumulation of deleterious mutations, which might affect the prevalence of different traits and diseases. Interestingly, many of the sex-specific genes that also undergo reduced selection efficiency are essential for successful reproduction in men or women. This seeming paradox might partially explain the high incidence of human infertility. This work provides a comprehensive overview of the sex-differential transcriptome and its importance to human evolution and human physiology in health and in disease.

Targeted deletion of MKK4 in cancer cells: a detrimental phenotype manifests as decreased experimental metastasis and suggests a counterweight to the evolution of tumor-suppressor loss.

PubMed

Cunningham, Steven C; Gallmeier, Eike; Hucl, Tomas; Dezentje, David A; Calhoun, Eric S; Falco, Geppino; Abdelmohsen, Kotb; Gorospe, Myriam; Kern, Scott E

2006-06-01

Tumor-suppressors have commanded attention due to the selection for their inactivating mutations in human tumors. However, relatively little is understood about the inverse, namely, that tumors do not select for a large proportion of seemingly favorable mutations in tumor-suppressor genes. This could be explained by a detrimental phenotype accruing in a cell type-specific manner to most cells experiencing a biallelic loss. For example, MKK4, a tumor suppressor gene distinguished by a remarkably consistent mutational rate across diverse tumor types and an unusually high rate of loss of heterozygosity, has the surprisingly low rate of genetic inactivation of only approximately 5%. To explore this incongruity, we engineered a somatic gene knockout of MKK4 in human cancer cells. Although the null cells resembled the wild-type cells regarding in vitro viability and proliferation in plastic dishes, there was a marked difference in a more relevant in vivo model of experimental metastasis and tumorigenesis. MKK4(-/-) clones injected i.v. produced fewer lung metastases than syngeneic MKK4-competent cells (P = 0.0034). These findings show how cell type-specific detrimental phenotypes can offer a paradoxical and yet key counterweight to the selective advantage attained by cells as they experiment with genetic null states during tumorigenesis, the resultant balance then determining the observed biallelic mutation rate for a given tumor-suppressor gene.

Human Keratinocytes Are Vanilloid Resistant

PubMed Central

Pecze, László; Szabó, Kornélia; Széll, Márta; Jósvay, Katalin; Kaszás, Krisztián; Kúsz, Erzsébet; Letoha, Tamás; Prorok, János; Koncz, István; Tóth, András; Kemény, Lajos; Vizler, Csaba; Oláh, Zoltán

2008-01-01

Background Use of capsaicin or resiniferatoxin (RTX) as analgesics is an attractive therapeutic option. RTX opens the cation channel inflammatory pain/vanilloid receptor type 1 (TRPV1) permanently and selectively removes nociceptive neurons by Ca2+-cytotoxicity. Paradoxically, not only nociceptors, but non-neuronal cells, including keratinocytes express full length TRPV1 mRNA, while patient dogs and experimental animals that underwent topical treatment or anatomically targeted molecular surgery have shown neither obvious behavioral, nor pathological side effects. Methods To address this paradox, we assessed the vanilloid sensitivity of the HaCaT human keratinocyte cell line and primary keratinocytes from skin biopsies. Results Although both cell types express TRPV1 mRNA, neither responded to vanilloids with Ca2+-cytotoxicity. Only ectopic overproduction of TRPV1 rendered HaCaT cells sensitive to low doses (1–50 nM) of vanilloids. The TRPV1-mediated and non-receptor specific Ca2+-cytotoxity ([RTX]>15 µM) could clearly be distinguished, thus keratinocytes were indeed resistant to vanilloid-induced, TRPV1-mediated Ca2+-entry. Having a wider therapeutic window than capsaicin, RTX was effective in subnanomolar range, but even micromolar concentrations could not kill human keratinocytes. Keratinocytes showed orders of magnitudes lower TRPV1 mRNA level than sensory ganglions, the bona fide therapeutic targets in human pain management. In addition to TRPV1, TRPV1b, a dominant negative splice variant was also noted in keratinocytes. Conclusion TRPV1B expression, together with low TRPV1 expression, may explain the vanilloid paradox: even genuinely TRPV1 mRNA positive cells can be spared with therapeutic (up to micromolar) doses of RTX. This additional safety information might be useful for planning future human clinical trials. PMID:18852901

Timing paradox of stepping and falls in ageing: not so quick and quick(er) on the trigger.

PubMed

Rogers, Mark W; Mille, Marie-Laure

2016-08-15

Physiological and degenerative changes affecting human standing balance are major contributors to falls with ageing. During imbalance, stepping is a powerful protective action for preserving balance that may be voluntarily initiated in recognition of a balance threat, or be induced by an externally imposed mechanical or sensory perturbation. Paradoxically, with ageing and falls, initiation slowing of voluntary stepping is observed together with perturbation-induced steps that are triggered as fast as or faster than for younger adults. While age-associated changes in sensorimotor conduction, central neuronal processing and cognitive functions are linked to delayed voluntary stepping, alterations in the coupling of posture and locomotion may also prolong step triggering. It is less clear, however, how these factors may explain the accelerated triggering of induced stepping. We present a conceptual model that addresses this issue. For voluntary stepping, a disruption in the normal coupling between posture and locomotion may underlie step-triggering delays through suppression of the locomotion network based on an estimation of the evolving mechanical state conditions for stability. During induced stepping, accelerated step initiation may represent an event-triggering process whereby stepping is released according to the occurrence of a perturbation rather than to the specific sensorimotor information reflecting the evolving instability. In this case, errors in the parametric control of induced stepping and its effectiveness in stabilizing balance would be likely to occur. We further suggest that there is a residual adaptive capacity with ageing that could be exploited to improve paradoxical triggering and other changes in protective stepping to impact fall risk. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

The implant infection paradox: why do some succeed when others fail? Opinion and discussion paper.

PubMed

Yue, C; Zhao, B; Ren, Y; Kuijer, R; van der Mei, H C; Busscher, H J; Rochford, E T J

2015-06-05

Biomaterial-implants are frequently used to restore function and form of human anatomy. However, the presence of implanted biomaterials dramatically elevates infection risk. Paradoxically, dental-implants placed in a bacteria-laden milieu experience moderate failure-rates, due to infection (0.0-1.1%), similar to the ones of joint-arthroplasties placed in a near-sterile environment (0.1-1.3%). Transcutaneous bone-fixation pins breach the immune-barrier of the epidermis, exposing underlying sterile-tissue to an unsterile external environment. In contrast to dental-implants, also placed in a highly unsterile environment, these pins give rise to relatively high infection-associated failure-rates of up to 23.0%. Herein, we attempt to identify causes as to why dental-implants so often succeed, where others fail. The major part of all implants considered are metal-made, with similar surface-finishes. Material choice was therefore discarded as underlying the paradox. Antimicrobial activity of saliva has also been suggested as a cause for the success of dental-implants, but was discarded because saliva is the implant-site-fluid from which viable bacteria adhere. Crevicular fluid was discarded as it is largely analogous to serum. Instead, we attribute the relative success of dental-implants to (1) ability of oral tissues to heal rapidly in the continuous presence of commensal bacteria and opportunistic pathogens, and (2) tolerance of the oral immune-system. Inability of local tissue to adhere, spread and grow in presence of bacteria and an intolerant immune-system are identified as the likely main causes explaining the susceptibility of other implants to infection-associated failure. In conclusion, it is the authors' belief that new anti-infection strategies for a wide range of biomaterial-implants may be derived from the relative success of dental-implants.

Obesity and coronary artery calcification: Can it explain the obesity-paradox?

PubMed

Aljizeeri, Ahmed; Coutinho, Thais; Pen, Ally; Chen, Li; Yam, Yeung; Dent, Robert; McPherson, Ruth; Chow, Benjamin J W

2015-06-01

The inverse relationship between obesity and adverse cardiovascular outcomes has been coined the 'obesity-paradox'. We sought to determine the relationship between measures of obesity [body mass index (BMI), body surface area (BSA) and body fat percentage (BF%)] and coronary artery calcification (CAC). We retrospectively analyzed patients who underwent CAC using the Agatston score. Baseline demographics were collected and BMI, BSA and BF% were calculated. A two-stage regression modeling approach was used to evaluate the association between BMI, BSA, BF% and Agatston score. Of the 6661 patients [mean age = 57.1 ± 10.8 years, men = 54.3%, median Agatston score = 14 (0, 163)], 0.1% were underweight, 21.3% had normal BMI, 39.1% were overweight and 39.4% were obese. The mean BMI, BSA and BF% were 29.6 ± 6.1 kg/m(2), 1.97 ± 0.25 m(2) and 37 ± 10 %, respectively. There was an independent association between the presence of CAC and BMI (5 kg/m(2) increments) (OR 1.05, CI 1.00-1.11, P = 0.038) and BF% (OR 2.38, CI 1.05-5.41, P = 0.038). Neither BMI categories nor large BSA independently predicted the presence of CAC. BF% predicted the extent of CAC in men but not in women, and higher BF% was associated with higher category of CAC severity in men only. BMI and BF% were independent predictors of the presence of CAC. BF% was associated with the extent of CAC and higher BF% was associated with higher category of CAC severity in men only. These results suggest that further study is needed to better understand the obesity-paradox.

Qualities and Inequalities in Online Social Networks through the Lens of the Generalized Friendship Paradox.

PubMed

Momeni, Naghmeh; Rabbat, Michael

2016-01-01

The friendship paradox is the phenomenon that in social networks, people on average have fewer friends than their friends do. The generalized friendship paradox is an extension to attributes other than the number of friends. The friendship paradox and its generalized version have gathered recent attention due to the information they provide about network structure and local inequalities. In this paper, we propose several measures of nodal qualities which capture different aspects of their activities and influence in online social networks. Using these measures we analyse the prevalence of the generalized friendship paradox over Twitter and we report high levels of prevalence (up to over 90% of nodes). We contend that this prevalence of the friendship paradox and its generalized version arise because of the hierarchical nature of the connections in the network. This hierarchy is nested as opposed to being star-like. We conclude that these paradoxes are collective phenomena not created merely by a minority of well-connected or high-attribute nodes. Moreover, our results show that a large fraction of individuals can experience the generalized friendship paradox even in the absence of a significant correlation between degrees and attributes.

Improvement of Antitumor Therapies Based on Vaccines and Immune-Checkpoint Inhibitors by Counteracting Tumor-Immunostimulation.

PubMed

Chiarella, Paula; Vermeulen, Mónica; Montagna, Daniela R; Vallecorsa, Pablo; Strazza, Ariel Ramiro; Meiss, Roberto P; Bustuoabad, Oscar D; Ruggiero, Raúl A; Prehn, Richmond T

2018-01-01

Immune-checkpoint inhibitors and antitumor vaccines may produce both tumor-inhibitory and tumor-stimulatory effects on growing tumors depending on the stage of tumor growth at which treatment is initiated. These paradoxical results are not necessarily incompatible with current tumor immunology but they might better be explained assuming the involvement of the phenomenon of tumor immunostimulation. This phenomenon was originally postulated on the basis that the immune response (IR) evoked in Winn tests by strong chemical murine tumors was not linear but biphasic, with strong IR producing inhibition and weak IR inducing stimulation of tumor growth. Herein, we extended those former observations to weak spontaneous murine tumors growing in pre-immunized, immune-competent and immune-depressed mice. Furthermore, we demonstrated that the interaction of specifical T cells and target tumor cells at low stimulatory ratios enhanced the production of chemokines aimed to recruit macrophages at the tumor site, which, upon activation of toll-like receptor 4 and p38 signaling pathways, would recruit and activate more macrophages and other inflammatory cells which would produce growth-stimulating signals leading to an accelerated tumor growth. On this basis, the paradoxical effects achieved by immunological therapies on growing tumors could be explained depending upon where the therapy-induced IR stands on the biphasic IR curve at each stage of tumor growth. At stages where tumor growth was enhanced (medium and large-sized tumors), counteraction of the tumor-immunostimulatory effect with anti-inflammatory strategies or, more efficiently, with selective inhibitors of p38 signaling pathways enabled the otherwise tumor-promoting immunological strategies to produce significant inhibition of tumor growth.

Improvement of Antitumor Therapies Based on Vaccines and Immune-Checkpoint Inhibitors by Counteracting Tumor-Immunostimulation

PubMed Central

Chiarella, Paula; Vermeulen, Mónica; Montagna, Daniela R.; Vallecorsa, Pablo; Strazza, Ariel Ramiro; Meiss, Roberto P.; Bustuoabad, Oscar D.; Ruggiero, Raúl A.; Prehn, Richmond T.

2018-01-01

Immune-checkpoint inhibitors and antitumor vaccines may produce both tumor-inhibitory and tumor-stimulatory effects on growing tumors depending on the stage of tumor growth at which treatment is initiated. These paradoxical results are not necessarily incompatible with current tumor immunology but they might better be explained assuming the involvement of the phenomenon of tumor immunostimulation. This phenomenon was originally postulated on the basis that the immune response (IR) evoked in Winn tests by strong chemical murine tumors was not linear but biphasic, with strong IR producing inhibition and weak IR inducing stimulation of tumor growth. Herein, we extended those former observations to weak spontaneous murine tumors growing in pre-immunized, immune-competent and immune-depressed mice. Furthermore, we demonstrated that the interaction of specifical T cells and target tumor cells at low stimulatory ratios enhanced the production of chemokines aimed to recruit macrophages at the tumor site, which, upon activation of toll-like receptor 4 and p38 signaling pathways, would recruit and activate more macrophages and other inflammatory cells which would produce growth-stimulating signals leading to an accelerated tumor growth. On this basis, the paradoxical effects achieved by immunological therapies on growing tumors could be explained depending upon where the therapy-induced IR stands on the biphasic IR curve at each stage of tumor growth. At stages where tumor growth was enhanced (medium and large-sized tumors), counteraction of the tumor-immunostimulatory effect with anti-inflammatory strategies or, more efficiently, with selective inhibitors of p38 signaling pathways enabled the otherwise tumor-promoting immunological strategies to produce significant inhibition of tumor growth. PMID:29435437

Induced seismicity constraints on subsurface geological structure, Paradox Valley, Colorado

NASA Astrophysics Data System (ADS)

Block, Lisa V.; Wood, Christopher K.; Yeck, William L.; King, Vanessa M.

2015-02-01

Precise relative hypocentres of seismic events induced by long-term fluid injection at the Paradox Valley Unit (PVU) brine disposal well provide constraints on the subsurface geological structure and compliment information available from deep seismic reflection and well data. We use the 3-D spatial distribution of the hypocentres to refine the locations, strikes, and throws of subsurface faults interpre­ted previously from geophysical surveys and to infer the existence of previously unidentified subsurface faults. From distinct epicentre lineations and focal mechanism trends, we identify a set of conjugate fracture orientations consistent with shear-slip reactivation of late-Palaeozoic fractures over a widespread area, as well as an additional fracture orientation present only near the injection well. We propose simple Mohr-Coulomb fracture models to explain these observations. The observation that induced seismicity preferentially occurs along one of the identified conjugate fracture orientations can be explained by a rotation in the direction of the regional maximum compressive stress from the time when the fractures were formed to the present. Shear slip along the third fracture orientation observed near the injection well is inconsistent with the current regional stress field and suggests a local rotation of the horizontal stresses. The detailed subsurface model produced by this analysis provides important insights for anticipating spatial patterns of future induced seismicity and for evaluation of possible additional injection well sites that are likely to be seismically and hydrologically isolated from the current well. In addition, the interpreted fault patterns provide constraints for estimating the maximum magnitude earthquake that may be induced, and for building geomechanical models to simulate pore pressure diffusion, stress changes and earthquake triggering.

Self field electromagnetism and quantum phenomena

NASA Astrophysics Data System (ADS)

Schatten, Kenneth H.

1994-07-01

Quantum Electrodynamics (QED) has been extremely successful inits predictive capability for atomic phenomena. Thus the greatest hope for any alternative view is solely to mimic the predictive capability of quantum mechanics (QM), and perhaps its usefulness will lie in gaining a better understanding of microscopic phenomena. Many ?paradoxes? and problematic situations emerge in QED. To combat the QED problems, the field of Stochastics Electrodynamics (SE) emerged, wherein a random ?zero point radiation? is assumed to fill all of space in an attmept to explain quantum phenomena, without some of the paradoxical concerns. SE, however, has greater failings. One is that the electromagnetic field energy must be infinit eto work. We have examined a deterministic side branch of SE, ?self field? electrodynamics, which may overcome the probelms of SE. Self field electrodynamics (SFE) utilizes the chaotic nature of electromagnetic emissions, as charges lose energy near atomic dimensions, to try to understand and mimic quantum phenomena. These fields and charges can ?interact with themselves? in a non-linear fashion, and may thereby explain many quantum phenomena from a semi-classical viewpoint. Referred to as self fields, they have gone by other names in the literature: ?evanesccent radiation?, ?virtual photons?, and ?vacuum fluctuations?. Using self fields, we discuss the uncertainty principles, the Casimir effects, and the black-body radiation spectrum, diffraction and interference effects, Schrodinger's equation, Planck's constant, and the nature of the electron and how they might be understood in the present framework. No new theory could ever replace QED. The self field view (if correct) would, at best, only serve to provide some understanding of the processes by which strange quantum phenomena occur at the atomic level. We discuss possible areas where experiments might be employed to test SFE, and areas where future work may lie.

Smoking and mortality in stroke survivors: can we eliminate the paradox?

PubMed

Levine, Deborah A; Walter, James M; Karve, Sudeep J; Skolarus, Lesli E; Levine, Steven R; Mulhorn, Kristine A

2014-07-01

Many studies have suggested that smoking does not increase mortality in stroke survivors. Index event bias, a sample selection bias, potentially explains this paradoxical finding. Therefore, we compared all-cause, cardiovascular disease (CVD), and cancer mortality by cigarette smoking status among stroke survivors using methods to account for index event bias. Among 5797 stroke survivors of 45 years or older who responded to the National Health Interview Survey years 1997-2004, an annual, population-based survey of community-dwelling US adults, linked to the National Death Index, we estimated all-cause, CVD, and cancer mortality by smoking status using Cox proportional regression and propensity score analysis to account for demographic, socioeconomic, and clinical factors. Mean follow-up was 4.5 years. From 1997 to 2004, 18.7% of stroke survivors smoked. There were 1988 deaths in this stroke survivor cohort, with 50% of deaths because of CVD and 15% because of cancer. Current smokers had an increased risk of all-cause mortality (hazard ratio [HR], 1.36; 95% confidence interval [CI], 1.14-1.63) and cancer mortality (HR, 3.83; 95% CI, 2.48-5.91) compared with never smokers, after controlling for demographic, socioeconomic, and clinical factors. Current smokers had an increased risk of CVD mortality controlling for age and sex (HR, 1.29; 95% CI, 1.01-1.64), but this risk did not persist after controlling for socioeconomic and clinical factors (HR, 1.15; 95% CI, .88-1.50). Stroke survivors who smoke have an increased risk of all-cause mortality, which is largely because of cancer mortality. Socioeconomic and clinical factors explain stroke survivors' higher risk of CVD mortality associated with smoking. Published by Elsevier Inc.

Paradoxical reaction to antituberculosis therapy in a patient with lupus vulgaris.

PubMed

Santesteban, R; Bonaut, B; Córdoba, A; Yanguas, I

2015-03-01

Patients receiving treatment for tuberculosis may experience an unexpected deterioration of their disease; this is known as a paradoxical reaction. We present the case of a 59-year-old man with lupus vulgaris who experienced a paradoxical deterioration of cutaneous lesions after starting antituberculosis therapy. The reaction was self-limiting; the lesions gradually improved, and the final outcome was very good. Paradoxical reactions are well-known in patients with human immunodeficiency virus (HIV) infection who start antiretroviral therapy, but they can also occur in non-HIV-infected patients with tuberculosis who start antituberculosis therapy. In the literature reviewed, paradoxical reactions involving skin lesions were described in patients with miliary tuberculosis. The case we report is the first of a paradoxical reaction in lupus vulgaris. The increasing frequency of tuberculosis in Spain could lead to a rise in the number of paradoxical reactions. Copyright © 2014 Elsevier España, S.L.U. y AEDV. All rights reserved.

From the BMI paradox to the obesity paradox: the obesity-mortality association in coronary heart disease.

PubMed

Antonopoulos, A S; Oikonomou, E K; Antoniades, C; Tousoulis, D

2016-10-01

Despite a strong association between body weight and mortality in the general population, clinical evidence suggests better clinical outcome of overweight or obese individuals with established coronary heart disease. This finding has been termed the 'obesity paradox', but its existence remains a point of debate, because it is mostly observed when body mass index (BMI) is used to define obesity. Inherent limitations of BMI as an index of adiposity, as well as methodological biases and the presence of confounding factors, may account for the observed findings of clinical studies. In this review, our aim is to present the data that support the presence of a BMI paradox in coronary heart disease and then explore whether next to a BMI paradox a true obesity paradox exists as well. We conclude by attempting to link the obesity paradox notion to available translational research data supporting a 'healthy', protective adipose tissue phenotype. © 2016 World Obesity. © 2016 World Obesity.

Generalized Hardy's Paradox

NASA Astrophysics Data System (ADS)

Jiang, Shu-Han; Xu, Zhen-Peng; Su, Hong-Yi; Pati, Arun Kumar; Chen, Jing-Ling

2018-01-01

Here, we present the most general framework for n -particle Hardy's paradoxes, which include Hardy's original one and Cereceda's extension as special cases. Remarkably, for any n ≥3 , we demonstrate that there always exist generalized paradoxes (with the success probability as high as 1 /2n -1) that are stronger than the previous ones in showing the conflict of quantum mechanics with local realism. An experimental proposal to observe the stronger paradox is also presented for the case of three qubits. Furthermore, from these paradoxes we can construct the most general Hardy's inequalities, which enable us to detect Bell's nonlocality for more quantum states.

Self-Interacting Dark Matter Can Explain Diverse Galactic Rotation Curves

NASA Astrophysics Data System (ADS)

Kamada, Ayuki; Kaplinghat, Manoj; Pace, Andrew B.; Yu, Hai-Bo

2017-09-01

The rotation curves of spiral galaxies exhibit a diversity that has been difficult to understand in the cold dark matter (CDM) paradigm. We show that the self-interacting dark matter (SIDM) model provides excellent fits to the rotation curves of a sample of galaxies with asymptotic velocities in the 25 - 300 km /s range that exemplify the full range of diversity. We assume only the halo concentration-mass relation predicted by the CDM model and a fixed value of the self-interaction cross section. In dark-matter-dominated galaxies, thermalization due to self-interactions creates large cores and reduces dark matter densities. In contrast, thermalization leads to denser and smaller cores in more luminous galaxies and naturally explains the flatness of rotation curves of the highly luminous galaxies at small radii. Our results demonstrate that the impact of the baryons on the SIDM halo profile and the scatter from the assembly history of halos as encoded in the concentration-mass relation can explain the diverse rotation curves of spiral galaxies.

Self-Interacting Dark Matter Can Explain Diverse Galactic Rotation Curves.

PubMed

Kamada, Ayuki; Kaplinghat, Manoj; Pace, Andrew B; Yu, Hai-Bo

2017-09-15

The rotation curves of spiral galaxies exhibit a diversity that has been difficult to understand in the cold dark matter (CDM) paradigm. We show that the self-interacting dark matter (SIDM) model provides excellent fits to the rotation curves of a sample of galaxies with asymptotic velocities in the 25-300  km/s range that exemplify the full range of diversity. We assume only the halo concentration-mass relation predicted by the CDM model and a fixed value of the self-interaction cross section. In dark-matter-dominated galaxies, thermalization due to self-interactions creates large cores and reduces dark matter densities. In contrast, thermalization leads to denser and smaller cores in more luminous galaxies and naturally explains the flatness of rotation curves of the highly luminous galaxies at small radii. Our results demonstrate that the impact of the baryons on the SIDM halo profile and the scatter from the assembly history of halos as encoded in the concentration-mass relation can explain the diverse rotation curves of spiral galaxies.

Cranial biomechanics underpins high sauropod diversity in resource-poor environments

PubMed Central

Button, David J.; Rayfield, Emily J.; Barrett, Paul M.

2014-01-01

High megaherbivore species richness is documented in both fossil and contemporary ecosystems despite their high individual energy requirements. An extreme example of this is the Late Jurassic Morrison Formation, which was dominated by sauropod dinosaurs, the largest known terrestrial vertebrates. High sauropod diversity within the resource-limited Morrison is paradoxical, but might be explicable through sophisticated resource partitioning. This hypothesis was tested through finite-element analysis of the crania of the Morrison taxa Camarasaurus and Diplodocus. Results demonstrate divergent specialization, with Camarasaurus capable of exerting and accommodating greater bite forces than Diplodocus, permitting consumption of harder food items. Analysis of craniodental biomechanical characters taken from 35 sauropod taxa demonstrates a functional dichotomy in terms of bite force, cranial robustness and occlusal relationships yielding two polyphyletic functional ‘grades’. Morrison taxa are widely distributed within and between these two morphotypes, reflecting distinctive foraging specializations that formed a biomechanical basis for niche partitioning between them. This partitioning, coupled with benefits associated with large body size, would have enabled the high sauropod diversities present in the Morrison Formation. Further, this provides insight into the mechanisms responsible for supporting the high diversities of large megaherbivores observed in other Mesozoic and Cenozoic communities, particularly those occurring in resource-limited environments. PMID:25297869

Mapping and determinism of soil microbial community distribution across an agricultural landscape

PubMed Central

Constancias, Florentin; Terrat, Sébastien; Saby, Nicolas P A; Horrigue, Walid; Villerd, Jean; Guillemin, Jean-Philippe; Biju-Duval, Luc; Nowak, Virginie; Dequiedt, Samuel; Ranjard, Lionel; Chemidlin Prévost-Bouré, Nicolas

2015-01-01

Despite the relevance of landscape, regarding the spatial patterning of microbial communities and the relative influence of environmental parameters versus human activities, few investigations have been conducted at this scale. Here, we used a systematic grid to characterize the distribution of soil microbial communities at 278 sites across a monitored agricultural landscape of 13 km². Molecular microbial biomass was estimated by soil DNA recovery and bacterial diversity by 16S rRNA gene pyrosequencing. Geostatistics provided the first maps of microbial community at this scale and revealed a heterogeneous but spatially structured distribution of microbial biomass and diversity with patches of several hundreds of meters. Variance partitioning revealed that both microbial abundance and bacterial diversity distribution were highly dependent of soil properties and land use (total variance explained ranged between 55% and 78%). Microbial biomass and bacterial richness distributions were mainly explained by soil pH and texture whereas bacterial evenness distribution was mainly related to land management. Bacterial diversity (richness, evenness, and Shannon index) was positively influenced by cropping intensity and especially by soil tillage, resulting in spots of low microbial diversity in soils under forest management. Spatial descriptors also explained a small but significant portion of the microbial distribution suggesting that landscape configuration also shapes microbial biomass and bacterial diversity. PMID:25833770

The role of competition – colonization tradeoffs and spatial heterogeneity in promoting trematode coexistence

USGS Publications Warehouse

Mordecai, Erin A.; Jaramillo, Alejandra G.; Ashford, Jacob E.; Hechinger, Ryan F.; Lafferty, Kevin D.

2016-01-01

Competition – colonization tradeoffs occur in many systems, and theory predicts that they can strongly promote species coexistence. However, there is little empirical evidence that observed competition – colonization tradeoffs are strong enough to maintain diversity in natural systems. This is due in part to a mismatch between theoretical assumptions and biological reality in some systems. We tested whether a competition – colonization tradeoff explains how a diverse trematode guild coexists in California horn snail populations, a system that meets the requisite criteria for the tradeoff to promote coexistence. A field experiment showed that subordinate trematode species tended to have higher colonization rates than dominant species. This tradeoff promoted coexistence in parameterized models but did not fully explain trematode diversity and abundance, suggesting a role of additional diversity maintenance mechanisms. Spatial heterogeneity is an alternative way to promote coexistence if it isolates competing species. We used scale transition theory to expand the competition – colonization tradeoff model to include spatial variation. The parameterized model showed that spatial variation in trematode prevalence did not isolate most species sufficiently to explain the overall high diversity, but could benefit some rare species. Together, the results suggest that several mechanisms combine to maintain diversity, even when a competition – colonization tradeoff occurs.

Seedling growth responses to light and mineral N form are predicted by species ecologies and can help explain tree diversity

Treesearch

Michael B. Walters; John L. Willis; Kurt W. Gottschalk

2014-01-01

Tree species distributions and diversity could be explained by rank changes in performance over multiple spatiotemporal resource gradients, i.e., resource partitioning. For 14 species planted in 45 harvest gap and closed canopy locations in a mesic northern hardwood forest community, Michigan, USA, we asked the following questions: (i) are species growth responses to...

Paradoxical aortic stenosis: A systematic review.

PubMed

Cavaca, Rita; Teixeira, Rogério; Vieira, Maria João; Gonçalves, Lino

2017-04-01

Aortic stenosis (AS) is a complex systemic valvular and vascular disease with a high prevalence in developed countries. The new entity "paradoxical low-flow, low-gradient aortic stenosis" refers to cases in which patients have severe AS based on assessment of aortic valve area (AVA) (≤1 cm 2 ) or indexed AVA (≤0.6 cm 2 /m 2 ), but paradoxically have a low mean transvalvular gradient (<40 mmHg) and a low stroke volume index (≤35 ml/m 2 ), despite preserved left ventricular ejection fraction (≥50%). A search was carried out in the PubMed database on paradoxical AS for the period 2007-2014. A total of 57 articles were included for this review. The prevalence of paradoxical AS ranged from 3% to 35% of the population with severe degenerative AS. It was more frequent in females and in older patients. Paradoxical AS was associated with characteristic left ventricular remodeling as well as an increase in systemic arterial stiffness. It was noted that there may be errors and inaccuracies in the calculation of AVA by the continuity equation, which could erroneously suggest the paradoxical phenotype. There are new diagnostic methods to facilitate the study of AS, such as aortic valve calcium score, valvuloarterial impedance and the longitudinal mechanics of the left ventricle. With regard to its natural history, it is not clear whether paradoxical AS corresponds to an advance stage of the disease or if paradoxical AS patients have a distinct phenotype with specific characteristics. Valve replacement, either surgical or percutaneous, may be indicated in patients with severe and symptomatic paradoxical AS. Copyright © 2016 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.

Middle ground approach to paradox: Within- and between-culture examination of the creative benefits of paradoxical frames.

PubMed

Leung, Angela K-Y; Liou, Shyhnan; Miron-Spektor, Ella; Koh, Brandon; Chan, David; Eisenberg, Roni; Schneider, Iris

2018-03-01

Thriving in increasingly complex and ambiguous environments requires creativity and the capability to reconcile conflicting demands. Recent evidence with Western samples has suggested that paradoxical frames, or mental templates that encourage individuals to recognize and embrace contradictions, could produce creative benefits. We extended the timely, but understudied, topic by studying the nuances of for whom and why creative advantages of paradoxical frames emerge. We suggest that people endorsing a middle ground approach are less likely to scrutinize conflict and reconcile with integrative solutions, thus receiving less creative benefits of paradoxical frames. Five studies that examined individual and cultural differences in middle ground endorsement support our theory. Study 1 found that paradoxical frames increased creativity, but failed to replicate that experienced conflict mediated the relationship in a Taiwanese sample. In both within- and between-culture analysis, we showed that the creative advantages of thinking paradoxically and experiencing conflict emerged among individuals who endorse lower (vs. higher) levels of middle ground (Study 2) and among Israelis whose culture predominantly endorses middle ground strategy less, but not among Singaporeans whose culture predominantly endorses middle ground more (Study 3). Study 4 further demonstrated the causal role of middle ground in the paradox-conflict-creativity link. To answer "why," Study 5 situationally induced integrative complex thinking that sets distinctions and forms syntheses among contradictory elements, and found that low endorsers of middle ground performed more creatively when they engaged integrative complex thinking to cope with paradoxes. This program of studies offers important insights on harnessing paradoxical experiences to catalyze creativity. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

CD47: A Master Regulator of Stemness | Center for Cancer Research

Cancer.gov

Identifying the pathways cells use to regulate proliferation, differentiation, and survival are essential for designing new treatments to stimulate organ and tissue repair following injury and for diseases as diverse as cancer and diabetes. The thrombospondin-1 receptor CD47 seems to limit cell survival and regeneration after stress. At the same time, CD47 levels are increased on the surface of cancer cells, which show enhanced proliferation and survival. To understand this apparent paradox, David Roberts, Ph.D., in CCR’s Laboratory of Pathology and his colleagues decided to investigate CD47’s mechanism of action using CD47- and thrombospondin-1-null mice.

First Impressions From Faces.

PubMed

Zebrowitz, Leslie A

2017-06-01

Although cultural wisdom warns 'don't judge a book by its cover,' we seem unable to inhibit this tendency even though it can produce inaccurate impressions of people's psychological traits and has significant social consequences. One explanation for this paradox is that first impressions of faces overgeneralize our adaptive impressions of categories of people that those faces resemble (including babies, familiar or unfamiliar people, unfit people, emotional people). Research testing these 'overgeneralization' hypotheses elucidates why we form first impressions from faces, what impressions we form, and what cues influence these impressions. This article focuses on commonalities in impressions across diverse perceivers. However, brief attention is given to individual differences in impressions and impression accuracy.

Unveiling consumer's privacy paradox behaviour in an economic exchange.

PubMed

Motiwalla, Luvai F; Li, Xiao-Bai

2016-01-01

Privacy paradox is of great interest to IS researchers and firms gathering personal information. It has been studied from social, behavioural, and economic perspectives independently. However, prior research has not examined the degrees of influence these perspectives contribute to the privacy paradox problem. We combine both economic and behavioural perspectives in our study of the privacy paradox with a price valuation of personal information through an economic experiment combined with a behavioural study on privacy paradox. Our goal is to reveal more insights on the privacy paradox through economic valuation on personal information. Results indicate that general privacy concerns or individual disclosure concerns do not have a significant influence on the price valuation of personal information. Instead, prior disclosure behaviour in specific scenario, like with healthcare providers or social networks, is a better indicator of consumer price valuations.

Unveiling consumer’s privacy paradox behaviour in an economic exchange

PubMed Central

Li, Xiao-Bai

2015-01-01

Privacy paradox is of great interest to IS researchers and firms gathering personal information. It has been studied from social, behavioural, and economic perspectives independently. However, prior research has not examined the degrees of influence these perspectives contribute to the privacy paradox problem. We combine both economic and behavioural perspectives in our study of the privacy paradox with a price valuation of personal information through an economic experiment combined with a behavioural study on privacy paradox. Our goal is to reveal more insights on the privacy paradox through economic valuation on personal information. Results indicate that general privacy concerns or individual disclosure concerns do not have a significant influence on the price valuation of personal information. Instead, prior disclosure behaviour in specific scenario, like with healthcare providers or social networks, is a better indicator of consumer price valuations. PMID:27708687

Ecological and evolutionary drivers of the elevational gradient of diversity.

PubMed

Laiolo, Paola; Pato, Joaquina; Obeso, José Ramón

2018-05-02

Ecological, evolutionary, spatial and neutral theories make distinct predictions and provide distinct explanations for the mechanisms that control the relationship between diversity and the environment. Here, we test predictions of the elevational diversity gradient focusing on Iberian bumblebees, grasshoppers and birds. Processes mediated by local abundance and regional diversity concur in explaining local diversity patterns along elevation. Effects expressed through variation in abundance were similar among taxa and point to the overriding role of a physical factor, temperature. This determines how energy is distributed among individuals and ultimately how the resulting pattern of abundance affects species incidence. Effects expressed through variation in regional species pools depended instead on taxon-specific evolutionary history, and lead to diverging responses under similar environmental pressures. Local filters and regional variation also explain functional diversity gradients, in line with results from species richness that indicate an (local) ecological and (regional) historical unfolding of diversity-elevation relationships. © 2018 John Wiley & Sons Ltd/CNRS.

Biogeographical Interpretation of Elevational Patterns of Genus Diversity of Seed Plants in Nepal

PubMed Central

Li, Miao; Feng, Jianmeng

2015-01-01

This study tests if the biogeographical affinities of genera are relevant for explaining elevational plant diversity patterns in Nepal. We used simultaneous autoregressive (SAR) models to investigate the explanatory power of several predictors in explaining the diversity-elevation relationships shown in genera with different biogeographical affinities. Delta akaike information criterion (ΔAIC) was used for multi-model inferences and selections. Our results showed that both the total and tropical genus diversity peaked below the mid-point of the elevational gradient, whereas that of temperate genera had a nearly symmetrical, unimodal relationship with elevation. The proportion of temperate genera increased markedly with elevation, while that of tropical genera declined. Compared to tropical genera, temperate genera had wider elevational ranges and were observed at higher elevations. Water-related variables, rather than mid-domain effects (MDE), were the most significant predictors of elevational patterns of tropical genus diversity. The temperate genus diversity was influenced by energy availability, but only in quadratic terms of the models. Though climatic factors and mid-domain effects jointly explained most of the variation in the diversity of temperate genera with elevation, the former played stronger roles. Total genus diversity was most strongly influenced by climate and the floristic overlap of tropical and temperate floras, while the influences of mid-domain effects were relatively weak. The influences of water-related and energy-related variables may vary with biogeographical affinities. The elevational patterns may be most closely related to climatic factors, while MDE may somewhat modify the patterns. Caution is needed when investigating the causal factors underlying diversity patterns for large taxonomic groups composed of taxa of different biogeographical affinities. Right-skewed diversity-elevation patterns may be produced by the differential response of taxa with varying biogeographical affinities to climatic factors and MDE. PMID:26488164

Biogeographical Interpretation of Elevational Patterns of Genus Diversity of Seed Plants in Nepal.

PubMed

Li, Miao; Feng, Jianmeng

2015-01-01

This study tests if the biogeographical affinities of genera are relevant for explaining elevational plant diversity patterns in Nepal. We used simultaneous autoregressive (SAR) models to investigate the explanatory power of several predictors in explaining the diversity-elevation relationships shown in genera with different biogeographical affinities. Delta akaike information criterion (ΔAIC) was used for multi-model inferences and selections. Our results showed that both the total and tropical genus diversity peaked below the mid-point of the elevational gradient, whereas that of temperate genera had a nearly symmetrical, unimodal relationship with elevation. The proportion of temperate genera increased markedly with elevation, while that of tropical genera declined. Compared to tropical genera, temperate genera had wider elevational ranges and were observed at higher elevations. Water-related variables, rather than mid-domain effects (MDE), were the most significant predictors of elevational patterns of tropical genus diversity. The temperate genus diversity was influenced by energy availability, but only in quadratic terms of the models. Though climatic factors and mid-domain effects jointly explained most of the variation in the diversity of temperate genera with elevation, the former played stronger roles. Total genus diversity was most strongly influenced by climate and the floristic overlap of tropical and temperate floras, while the influences of mid-domain effects were relatively weak. The influences of water-related and energy-related variables may vary with biogeographical affinities. The elevational patterns may be most closely related to climatic factors, while MDE may somewhat modify the patterns. Caution is needed when investigating the causal factors underlying diversity patterns for large taxonomic groups composed of taxa of different biogeographical affinities. Right-skewed diversity-elevation patterns may be produced by the differential response of taxa with varying biogeographical affinities to climatic factors and MDE.

An Acid Hydrocarbon: A Chemical Paradox

ERIC Educational Resources Information Center

Burke, Jeffrey T.

2004-01-01

The chemical paradox of cyclopentadiene, a hydrocarbon, producing bubbles like a Bronsted acid is observed. The explanation that it is the comparative thermodynamic constancy of the fragrant cyclopentadienyl anion, which produces the powerful effect, resolves the paradox.

Einstein-Podolsky-Rosen paradox and quantum steering in pulsed optomechanics

NASA Astrophysics Data System (ADS)

He, Q. Y.; Reid, M. D.

2013-11-01

We describe how to generate an Einstein-Podolsky-Rosen (EPR) paradox between a mesoscopic mechanical oscillator and an optical pulse. We find two types of paradox, defined by whether it is the oscillator or the pulse that shows the effect Schrödinger called “steering”. Only the oscillator paradox addresses the question of mesoscopic local reality for a massive system. In that case, EPR's “elements of reality” are defined for the oscillator, and it is these elements of reality that are falsified (if quantum mechanics is complete). For this sort of paradox, we show that a thermal barrier exists, meaning that a threshold level of pulse-oscillator interaction is required for a given thermal occupation n0 of the oscillator. We find there is no equivalent thermal barrier for the entanglement of the pulse with the oscillator or for the EPR paradox that addresses the local reality of the optical system. Finally, we examine the possibility of an EPR paradox between two entangled oscillators. Our work highlights the asymmetrical effect of thermal noise on quantum nonlocality.

The Second Law and Quantum Physics

NASA Astrophysics Data System (ADS)

Bennett, Charles H.

2008-08-01

In this talk, I discuss the mystery of the second law and its relation to quantum information. There are many explanations of the second law, mostly satisfactory and not mutually exclusive. Here, I advocate quantum mechanics and quantum information as something that, through entanglement, helps resolve the paradox or the puzzle of the origin of the second law. I will discuss the interpretation called quantum Darwinism and how it helps explain why our world seems so classical, and what it has to say about the permanence or transience of information. And I will discuss a simple model illustrating why systems away from thermal equilibrium tend to be more complicated.

The four antinomies of the death instinct.

PubMed

Blanco, Ignacio Matte

2005-10-01

Matte Blanco examines four paradoxical positions that arise out of Freud's writings on the death instinct. He notes that death is not a content known to the unconscious. Furthermore, the absence of time and space in the unconscious means that the conditions necessary for any process such as instinct are similarly absent. Matte Blanco demonstrates the way in which the antinomies that he explores can be explained in terms of the logics that obtain in the unconscious, and he suggests that the concept of the death instinct is one of the most profound expressions of the relationship between the modes that underlie conscious and unconscious logic.

Economic Growth Evens Out Happiness: Evidence from Six Surveys.

PubMed

Clark, Andrew E; Flèche, Sarah; Senik, Claudia

2016-09-01

In spite of the great U-turn that saw income inequality rise in Western countries in the 1980s, happiness inequality has fallen in countries that have experienced income growth (but not in those that did not). Modern growth has reduced the share of both the "very unhappy" and the "perfectly happy". Lower happiness inequality is found both between and within countries, and between and within individuals. Our cross-country regression results argue that the extension of various public goods helps to explain this greater happiness homogeneity. This new stylised fact arguably comes as a bonus to the Easterlin paradox, offering a somewhat brighter perspective for developing countries.

Skyscrapers in the Desert: Observing Ongoing, Active Star Formation in the Low-Density Wing of the Small Magellanic Cloud

NASA Astrophysics Data System (ADS)

Fulmer, Leah M.; Gallagher, John S.; Hamann, Wolf-Rainer; Oskinova, Lida; Ramachandran, Varsha

2018-01-01

The low-density Wing of the Small Magellanic Cloud exhibits ongoing, active star formation despite a distinctive lack of dense ambient gas and dust, or resources from which to form stars. Our continued work in studying this region reveals that these paradoxical observations may be explained by a process of sequential star formation. We present photometric, clustering, and spatial analyses in support of this scenario, along with a proposed star formation history based on the following evidence: matches to isochrone models, stellar and ionized gas kinematics (VLT, SALT), and regional HI gas kinematics (ATCA, PKS).

Unthermal Charged Massive Hawking Radiation from a Reissner-Nordström Black Hole

NASA Astrophysics Data System (ADS)

Zhou, Shiwei; Liu, Wenbiao

2008-03-01

Using Damour-Ruffini’s method, the massive charged particles’ Hawking radiation from a Reissner-Nordström black hole is investigated. When the back-reaction of particles’ energy and charge to spacetime is considered, we get the unthermal spectrum. It is possible that the information will get out from the black hole with the corrected spectrum. It can be used to explain the information loss paradox, and the underlying unitary theory will be satisfied. The same conclusion as the works finished before can be drawn. However, our work is different from them, and the method is more simple and explicit.

Contralateral pulmonary metastases in lung cancer

PubMed Central

Onuigbo, Wilson I. B.

1974-01-01

Onuigbo, W. I. B. (1974).Thorax, 29, 132-133. Contralateral pulmonary metastases in lung cancer. It has long been known that lung cancer may attack many organs and yet spare the opposite lung. In 100 cases of this tumour studied at necropsy, only 22 showed contralateral pulmonary spread. Contralateral deposits are generally small and may be related to damaged tissues. Although tissue unsuitability is supposed to underlie the limitation of metastases in recipient organs, this does not apply to the contralateral lung. Since lung tissue is readily accessible to bloodborne cancer cells, research should be directed towards explaining the paradoxical paucity of the metastases. PMID:4825544

Relationships between plant diversity and grasshopper diversity and abundance in the Little Missouri National Grassland

USDA-ARS?s Scientific Manuscript database

A continuing challenge in Orthoptera ecology is to understand what determines grasshopper species diversity at a given site. In this study, the objective was to determine if variation in grasshopper abundance and diversity between 23 sites in western North Dakota (USA) could be explained by variatio...

Considering risk contexts in explaining the paradoxical HIV increase among female sex workers in Mumbai and Thane, India.

PubMed

Bandewar, Sunita V S; Bharat, Shalini; Kongelf, Anine; Pisal, Hemlata; Collumbien, Martine

2016-01-28

The period 2006-2009 saw intensive scale-up of HIV prevention efforts and an increase in reported safer sex among brothel and street-based sex workers in Mumbai and Thane (Maharashtra, India). Yet during the same period, the prevalence of HIV increased in these groups. A better understanding of sex workers' risk environment is needed to explain this paradox. In this qualitative study we conducted 36 individual interviews, 9 joint interviews, and 10 focus group discussions with people associated with HIV interventions between March and May 2012. Dramatic changes in Mumbai's urban landscape dominated participants' accounts, with dwindling sex worker numbers in traditional brothel areas attributed to urban restructuring. Gentrification and anti-trafficking efforts explained an escalation in police raids. This contributed to dispersal of sex work with the sex-trade management adapting by becoming more hidden and mobile, leading to increased vulnerability. Affordable mobile phone technology enabled independent sex workers to trade in more hidden ways and there was an increased dependence on lovers for support. The risk context has become ever more challenging, with animosity against sex work amplified since the scale up of targeted interventions. Focus on condom use with sex workers inadvertently contributed to the diversification of the sex trade as clients seek out women who are less visible. Sex workers and other marginalised women who sell sex all strictly prioritise anonymity. Power structures in the sex trade continue to pose insurmountable barriers to reaching young and new sex workers. Economic vulnerability shaped women's decisions to compromise on condom use. Surveys monitoring HIV prevalence among 'visible' street and brothel-bases sex workers are increasingly un-representative of all women selling sex and self-reported condom use is no longer a valid measure of risk reduction. Targeted harm reduction programmes with sex workers fail when implemented in complex urban environments that favour abolition. Increased stigmatisation and dispersal of risk can no longer be considered as unexpected. Reaching the increasing proportion of sex workers who intentionally avoid HIV prevention programmes has become the main challenge. Future evaluations need to incorporate building 'dark logic' models to predict potential harms.

The complex roles of space and environment in structuring functional, taxonomic and phylogenetic beta diversity of frogs in the Atlantic Forest

PubMed Central

Luiz, Amom Mendes; Sawaya, Ricardo J.

2018-01-01

Ecological communities are complex entities that can be maintained and structured by niche-based processes such as environmental conditions, and spatial processes such as dispersal. Thus, diversity patterns may be shaped simultaneously at different spatial scales by very distinct processes. Herein we assess whether and how functional, taxonomic, and phylogenetic beta diversities of frog tadpoles are explained by environmental and/or spatial predictors. We implemented a distance–based redundancy analysis to explore variation in components of beta diversity explained by pure environmental and pure spatial predictors, as well as their interactions, at both fine and broad spatial scales. Our results indicated important but complex roles of spatial and environmental predictors in structuring phylogenetic, taxonomic and functional beta diversities. The pure fine-scales spatial fraction was more important in structuring all beta diversity components, especially to functional and taxonomical spatial turnover. Environmental variables such as canopy cover and vegetation structure were important predictors of all components, but especially to functional and taxonomic beta diversity. We emphasize that distinct factors related to environment and space are affecting distinct components of beta diversity in different ways. Although weaker, phylogenetic beta diversity, which is structured more on biogeographical scales, and thus can be represented by spatially structured processes, was more related to broad spatial processes than other components. However, selected fine-scale spatial predictors denoted negative autocorrelation, which may be revealing the existence of differences in unmeasured habitat variables among samples. Although overall important, local environmental-based processes explained better functional and taxonomic beta diversity, as these diversity components carry an important ecological value. We highlight the importance of assessing different components of diversity patterns at different scales by spatially explicit models in order to improve our understanding of community structure and help to unravel the complex nature of biodiversity. PMID:29672575

Simpson's Paradox: Examples.

PubMed

Wang, Bokai; Wu, Pan; Kwan, Brian; Tu, Xin M; Feng, Changyong

2018-04-25

Simpson's paradox is very prevalent in many areas. It characterizes the inconsistency between the conditional and marginal interpretations of the data. In this paper, we illustrate through some examples how the Simpson's paradox can happen in continuous, categorical, and time-to-event data.

Epidemiology of Myocardial Infarction Caused by Presumed Paradoxical Embolism via a Patent Foramen Ovale.

PubMed

Kleber, Franz X; Hauschild, Telse; Schulz, Antonia; Winkelmann, Anne; Bruch, Leonhard

2017-09-25

Despite several negative prospective randomized trials on the efficacy of patent foramen ovale (PFO) occlusion, the discussion on indications is ongoing. Because the incidence of paradoxical coronary embolism through a PFO is unknown, we investigated the risk of paradoxical embolic myocardial infarction over a period of 13 years.Methods and Results:We conducted a retrospective and a prospective study. In the former, we searched the hospital database of a tertiary referral center for cases of acute myocardial infarction (AMI) during the past 10 years and screened them for possible paradoxical MIs. On this basis we started a prospective evaluation over 39 months in another tertiary referral center. All patients with AMI and normal coronary arteries were screened for PFO and if no other reason for the AMI could be found, the case was judged as presumed paradoxical embolism. In the retrospective analysis we found 22 cases (0.45%) of presumed paradoxical coronary artery embolism under 4,848 AMI. In the prospective study there were 11 presumed paradoxical coronary artery embolisms among 1,654 patients with AMI, representing an incidence of 0.67%. Our findings demonstrated that well below 1% of AMIs are caused by paradoxical embolism via an interatrial communication. Although this percentage appears low, it is not a negligible number of patients based on the huge number of MIs occurring in the industrialized world.

Perspectives on Intracluster Enrichment and the Stellar Initial Mass Function in Elliptical Galaxies

NASA Technical Reports Server (NTRS)

Lowenstein, Michael

2013-01-01

The amount of metals in the Intracluster Medium (ICM) in rich galaxy clusters exceeds that expected based on the observed stellar population by a large factor. We quantify this discrepancy--which we term the "cluster elemental abundance paradox"--and investigate the required properties of the ICM-enriching population. The necessary enhancement in metal enrichment may, in principle, originate in the observed stellar population if a larger fraction of stars in the supernova-progenitor mass range form from an initial mass function (IMF) that is either bottom-light or top-heavy, with the latter in some conflict with observed ICM abundance ratios. Other alternatives that imply more modest revisions to the IMF, mass return and remnant fractions, and primordial fraction, posit an increase in the fraction of 3-8 solar mass stars that explode as SNIa or assume that there are more stars than conventionally thought--although the latter implies a high star formation efficiency. We discuss the feasibility of these various solutions and the implications for the diversity of star formation, the process of elliptical galaxy formation, and the nature of this hidden source of ICM metal enrichment in light of recent evidence of an elliptical galaxy IMF that, because it is skewed to low masses, deepens the paradox.

Postcopulatory sexual selection: Darwin's omission and its consequences

PubMed Central

Eberhard, William G.

2009-01-01

In one of his few major oversights, Darwin failed to appreciate that male–male competition and sexual selection can continue even after copulation has begun. The postcopulatory equivalents of both direct male–male battles (sperm competition) and female choice (cryptic female choice) occur within the female's body. Recognition of this hidden, but intense, sexual competition provides new insights into a variety of fields. These include the hyperdiverse and paradoxically elaborate morphology of both sperm and male genitalia, the equally puzzling and elaborate morphology of nongenitalic male structures that are specialized to grasp and stimulate females, powerful manipulative effects of substances in male semen on female reproductive physiology, paradoxical male courtship behavior that occurs after copulation has already begun, variability in parental investments, and the puzzlingly complex and diverse interactions between sperm and female products that surround animal eggs and between male gametophytes and female tissues in flowering plants. Many bizarre traits are involved, including male genitalia that are designed to explode or fall apart during copulation leaving behind parts within the female, male genitalia that “sing” during copulation, potent seminal products that invade the female's body cavity and her nervous system to influence her behavior, and a virtual Kama Sutra of courtship behavior performed after rather than before genital coupling, including male–female dialogues during copulation. PMID:19528642

Ca2+ paradox injury mediated through TRPC channels in mouse ventricular myocytes

PubMed Central

Kojima, Akiko; Kitagawa, Hirotoshi; Omatsu-Kanbe, Mariko; Matsuura, Hiroshi; Nosaka, Shuichi

2010-01-01

BACKGROUND AND PURPOSE The Ca2+ paradox is an important phenomenon associated with Ca2+ overload-mediated cellular injury in myocardium. The present study was undertaken to elucidate molecular and cellular mechanisms for the development of the Ca2+ paradox. EXPERIMENTAL APPROACH Fluorescence imaging was performed on fluo-3 loaded quiescent mouse ventricular myocytes using confocal laser scanning microscope. KEY RESULTS The Ca2+ paradox was readily evoked by restoration of the extracellular Ca2+ following 10–20 min of nominally Ca2+-free superfusion. The Ca2+ paradox was significantly reduced by blockers of transient receptor potential canonical (TRPC) channels (2-aminoethoxydiphenyl borate, Gd3+, La3+) and anti-TRPC1 antibody. The sarcoplasmic reticulum (SR) Ca2+ content, assessed by caffeine application, gradually declined during Ca2+-free superfusion, which was further accelerated by metabolic inhibition. Block of SR Ca2+ leak by tetracaine prevented Ca2+ paradox. The Na+/Ca2+ exchange (NCX) blocker KB-R7943 significantly inhibited Ca2+ paradox when applied throughout superfusion period, but had little effect when added for a period of 3 min before and during Ca2+ restoration. The SR Ca2+ content was better preserved during Ca2+ depletion by KB-R7943. Immunocytochemistry confirmed the expression of TRPC1, in addition to TRPC3 and TRPC4, in mouse ventricular myocytes. CONCLUSIONS AND IMPLICATIONS These results provide evidence that (i) the Ca2+ paradox is primarily mediated by Ca2+ entry through TRPC (probably TRPC1) channels that are presumably activated by SR Ca2+ depletion; and (ii) reverse mode NCX contributes little to the Ca2+ paradox, whereas inhibition of NCX during Ca2+ depletion improves SR Ca2+ loading, and is associated with reduced incidence of Ca2+ paradox in mouse ventricular myocytes. PMID:20718730

Mapping and determinism of soil microbial community distribution across an agricultural landscape.

PubMed

Constancias, Florentin; Terrat, Sébastien; Saby, Nicolas P A; Horrigue, Walid; Villerd, Jean; Guillemin, Jean-Philippe; Biju-Duval, Luc; Nowak, Virginie; Dequiedt, Samuel; Ranjard, Lionel; Chemidlin Prévost-Bouré, Nicolas

2015-06-01

Despite the relevance of landscape, regarding the spatial patterning of microbial communities and the relative influence of environmental parameters versus human activities, few investigations have been conducted at this scale. Here, we used a systematic grid to characterize the distribution of soil microbial communities at 278 sites across a monitored agricultural landscape of 13 km². Molecular microbial biomass was estimated by soil DNA recovery and bacterial diversity by 16S rRNA gene pyrosequencing. Geostatistics provided the first maps of microbial community at this scale and revealed a heterogeneous but spatially structured distribution of microbial biomass and diversity with patches of several hundreds of meters. Variance partitioning revealed that both microbial abundance and bacterial diversity distribution were highly dependent of soil properties and land use (total variance explained ranged between 55% and 78%). Microbial biomass and bacterial richness distributions were mainly explained by soil pH and texture whereas bacterial evenness distribution was mainly related to land management. Bacterial diversity (richness, evenness, and Shannon index) was positively influenced by cropping intensity and especially by soil tillage, resulting in spots of low microbial diversity in soils under forest management. Spatial descriptors also explained a small but significant portion of the microbial distribution suggesting that landscape configuration also shapes microbial biomass and bacterial diversity. © 2015 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

Social Justice and Cultural Diversity Issues

ERIC Educational Resources Information Center

Harley, Debra A.; Alston, Reginald J.; Turner-Whittaker, Tyra

2008-01-01

Early definitions of cultural diversity focused primarily on race/ethnicity, with subsequent inclusion of age, gender, sexual orientation, class, religion, geography, and a combination of positionalities. More recently, social justice has resurfaced as a component of cultural diversity to explain experiences of people of color, women, and…

Debating Diversity: Ethics and Controversial Public Issues

ERIC Educational Resources Information Center

Darr, Christopher R.

2016-01-01

Courses: Ethics, Organizational Communication, Political Communication. Objectives: After completing this unit activity, students should be able to (1) apply multiple ethical perspectives to real-world diversity issues in a debate format, and (2) explain the role of informational and social category diversity in current controversies.

The "Paradox of Interdisciplinarity" in Australian Research Governance

ERIC Educational Resources Information Center

Woelert, Peter; Millar, Victoria

2013-01-01

This paper identifies what can be called the "paradox of interdisciplinarity" (Weingart 2000) in Australian higher education research governance and explores some of its constitutive dimensions. In the Australian context, the paradox of interdisciplinarity primarily concerns the proliferation of a programmatic discourse of…

The Simpson's paradox unraveled

PubMed Central

Hernán, Miguel A; Clayton, David; Keiding, Niels

2011-01-01

Background In a famous article, Simpson described a hypothetical data example that led to apparently paradoxical results. Methods We make the causal structure of Simpson's example explicit. Results We show how the paradox disappears when the statistical analysis is appropriately guided by subject-matter knowledge. We also review previous explanations of Simpson's paradox that attributed it to two distinct phenomena: confounding and non-collapsibility. Conclusion Analytical errors may occur when the problem is stripped of its causal context and analyzed merely in statistical terms. PMID:21454324

No information or horizon paradoxes for Th. Smiths

NASA Astrophysics Data System (ADS)

Maes, Christian

2015-10-01

The Statistical mechanician in the street (our Th. Smiths) must be surprised upon hearing popular versions of some of today's most discussed paradoxes in astronomy and cosmology. In fact, rather standard reminders of the meaning of thermal probabilities in statistical mechanics appear to answer the horizon problem (one of the major motivations for inflation theory) and the information paradox (related to black hole physics), at least as they are usually presented. Still the paradoxes point to interesting gaps in our statistical understanding of (quantum) gravitational effects.

Herbivory enhances the diversity of primary producers in pond ecosystems.

PubMed

Leibold, Mathew A; Hall, Spencer R; Smith, Val H; Lytle, David A

2017-01-01

Diversity of primary producer is often surprisingly high, despite few limiting factors such as nutrients and light to facilitate species coexistence. In theory, the presence of herbivores could increase the diversity of primary producers, resolving this "paradox of the plankton." Little experimental evidence supports this natural enemies hypothesis, but previous tests suffer from several deficiencies. Previous experiments often did not allow for multigeneration effects; utilized low diversity assemblages of herbivores; and limited opportunities for new primary producer and herbivore species to colonize and undergo species sorting that favors some species over others. Using pond plankton, we designed a mesocosm experiment that overcame these problems by allowing more time for interactions over multiple generations, openness to allow new colonists, and manipulated higher diversity of primary producers and grazers than have previous studies. With this design, the presence of zooplankton grazers doubled phytoplankton richness. The additional phytoplankton species in grazed mesocosms were larger, and therefore likely more grazer resistant. Furthermore, phytoplankton richness in grazed mesocosms was similar to that observed in natural ponds whereas it was much lower in mesocosms without grazers. However, stoichiometric imbalance caused by variation in nitrogen : phosphorus ratios and light supply did not alter phytoplankton richness. Therefore, grazers enhanced primary producer richness more strongly than ratios of nutrient supply (even though both grazing and ratios of resource supply altered composition of primary producer assemblages). Taken together, these experimental and field data show that grazing from a diverse assemblage of herbivores greatly elevated richness of phytoplankton producers in pond ecosystems. © 2016 by the Ecological Society of America.

Paradoxical (REM) sleep deprivation in mice using the small-platforms-over-water method: polysomnographic analyses and melanin-concentrating hormone and hypocretin/orexin neuronal activation before, during and after deprivation.

PubMed

Arthaud, Sebastien; Varin, Christophe; Gay, Nadine; Libourel, Paul-Antoine; Chauveau, Frederic; Fort, Patrice; Luppi, Pierre-Herve; Peyron, Christelle

2015-06-01

Studying paradoxical sleep homeostasis requires the specific and efficient deprivation of paradoxical sleep and the evaluation of the subsequent recovery period. With this aim, the small-platforms-over-water technique has been used extensively in rats, but only rare studies were conducted in mice, with no sleep data reported during deprivation. Mice are used increasingly with the emergence of transgenic mice and technologies such as optogenetics, raising the need for a reliable method to manipulate paradoxical sleep. To fulfil this need, we refined this deprivation method and analysed vigilance states thoroughly during the entire protocol. We also studied activation of hypocretin/orexin and melanin-concentrating hormone neurones using Fos immunohistochemistry to verify whether mechanisms regulating paradoxical sleep in mice are similar to those in rats. We showed that 48 h of deprivation was highly efficient, with a residual amount of paradoxical sleep of only 2.2%. Slow wave sleep and wake quantities were similar to baseline, except during the first 4 h of deprivation, where slow wave sleep was strongly reduced. After deprivation, we observed a 124% increase in paradoxical sleep quantities during the first hour of rebound. In addition, 34% of hypocretin/orexin neurones were activated during deprivation, whereas melanin-concentrated hormone neurones were activated only during paradoxical sleep rebound. Corticosterone level showed a twofold increase after deprivation and returned to baseline level after 4 h of recovery. In summary, a fairly selective deprivation and a significant rebound of paradoxical sleep can be obtained in mice using the small-platforms-over-water method. As in rats, rebound is accompanied by a selective activation of melanin-concentrating hormone neurones. © 2014 European Sleep Research Society.

Greenberger-Horne-Zeilinger paradoxes from qudit graph states.

PubMed

Tang, Weidong; Yu, Sixia; Oh, C H

2013-03-08

One fascinating way of revealing quantum nonlocality is the all-versus-nothing test due to Greenberger, Horne, and Zeilinger (GHZ) known as the GHZ paradox. So far genuine multipartite and multilevel GHZ paradoxes are known to exist only in systems containing an odd number of particles. Here we shall construct GHZ paradoxes for an arbitrary number (greater than 3) of particles with the help of qudit graph states on a special kind of graphs, called GHZ graphs. Furthermore, based on the GHZ paradox arising from a GHZ graph, we derive a Bell inequality with two d-outcome observables for each observer, whose maximal violation attained by the corresponding graph state, and a Kochen-Specker inequality testing the quantum contextuality in a state-independent fashion.

Emotion and false memory: The context-content paradox.

PubMed

Bookbinder, S H; Brainerd, C J

2016-12-01

False memories are influenced by a variety of factors, but emotion is a variable of special significance, for theoretical and practical reasons. Interestingly, emotion's effects on false memory depend on whether it is embedded in the content of to-be-remembered events or in our moods, where mood is an aspect of the context in which events are encoded. We sketch the theoretical basis for this content-context dissociation and then review accumulated evidence that content and context effects are indeed different. Paradoxically, we find that in experiments on spontaneous and implanted false memories, negatively valenced content foments distortion, but negatively valenced moods protect against it. In addition, correlational data show that enduring negative natural moods (e.g., depression) foment false memory. Current opponent-process models of false memory, such as fuzzy-trace theory, are able to explain the content-context dissociation: Variations in emotional content primarily affect memory for the gist of events, whereas variations in emotional context primarily affect memory for events' exact verbatim form. Important questions remain about how these effects are modulated by variations in memory tests and in arousal. Promising methods of tackling those questions are outlined, especially designs that separate the gist and verbatim influences of emotion. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Demography of Symbiotic Nitrogen-Fixing Trees Explains Their Rarity and Successional Decline in Temperate Forests in the United States.

PubMed

Liao, Wenying; Menge, Duncan N L

2016-01-01

Symbiotic nitrogen (N) fixation is the major N input to many ecosystems. Although temperate forests are commonly N limited, symbiotic N-fixing trees ("N fixers") are rare and decline in abundance as succession proceeds-a challenging paradox that remains unexplained. Understanding demographic processes that underlie N fixers' rarity and successional decline would provide a proximate answer to the paradox. Do N fixers grow slower, die more frequently, or recruit less in temperate forests? We quantified demographic rates of N-fixing and non-fixing trees across succession using U.S. forest inventory data. We used an individual-based model to evaluate the relative contribution of each demographic process to community dynamics. Compared to non-fixers, N fixers had lower growth rates, higher mortality rates, and lower recruitment rates throughout succession. The mortality effect contributed more than the growth effect to N fixers' successional decline. Canopy and understory N fixers experienced these demographic disadvantages, indicating that factors in addition to light limitation likely contribute to N fixers' successional decline. We show that the rarity and successional decline of N-fixing trees in temperate forests is due more to their survival disadvantage than their growth disadvantage, and a recruitment disadvantage might also play a large role.

Use of medicines by older people in a large British national survey, and their relation to vitamin status indices.

PubMed

Bates, C J; Walmsley, C M; Prentice, A; Finch, S

1999-03-01

To describe the extent of use of medicines by older people living in Britain, and to explore relationships with vitamin status indices. The National Diet and Nutrition Survey of people aged 65 years and over collected data from a British sample during 1994-95. The present study has made novel use of it, to relate medicine use with biochemical indices of vitamin status. Eighty postcode areas, selected randomly from mainland Britain. 1506 people, 65 years and over gave information about use of medication, and a 4-day weighed food record. Three-quarters gave blood for status indices. 78% of those living in the community and 93% of those in institutions were using medication. Certain vitamin status indices: plasma retinol, erythrocyte folate and riboflavin, paradoxically suggested better status in users than in non-users of antihypertensive, gastrointestinal, central nervous system, corticosteroid or diabetic drugs. There was evidence of a link with renal insufficiency, especially for plasma retinol, but neither this nor increased nutrient intake, acute phase effects or haemoconcentration could explain the paradoxical associations. Caution is needed in interpreting certain vitamin status indices, especially in older people who are extensively using medicines. New vitamin indices are needed, to avoid confounding interferences.

Less is more: Patient-level meta-analysis reveals paradoxical dose-response effects of a computer-based social anxiety intervention targeting attentional bias.

PubMed

Price, Rebecca B; Kuckertz, Jennie M; Amir, Nader; Bar-Haim, Yair; Carlbring, Per; Wallace, Meredith L

2017-12-01

The past decade of research has seen considerable interest in computer-based approaches designed to directly target cognitive mechanisms of anxiety, such as attention bias modification (ABM). By pooling patient-level datasets from randomized controlled trials of ABM that utilized a dot-probe training procedure, we assessed the impact of training "dose" on relevant outcomes among a pooled sample of 693 socially anxious adults. A paradoxical effect of the number of training trials administered was observed for both posttraining social anxiety symptoms and behavioral attentional bias (AB) toward threat (the target mechanism of ABM). Studies administering a large (>1,280) number of training trials showed no benefit of ABM over control conditions, while those administering fewer training trials showed significant benefit for ABM in reducing social anxiety (P = .02). These moderating effects of dose were not better explained by other examined variables and previously identified moderators, including patient age, training setting (laboratory vs. home), or type of anxiety assessment (clinician vs. self-report). Findings inform the optimal dosing for future dot-probe style ABM applications in both research and clinical settings, and suggest several novel avenues for further research. © 2017 Wiley Periodicals, Inc.

Changes in cerebral metabolism in patients with a minimally conscious state responding to zolpidem

PubMed Central

Chatelle, Camille; Thibaut, Aurore; Gosseries, Olivia; Bruno, Marie-Aurélie; Demertzi, Athena; Bernard, Claire; Hustinx, Roland; Tshibanda, Luaba; Bahri, Mohamed A.; Laureys, Steven

2014-01-01

Background: Zolpidem, a short-acting non-benzodiazepine GABA agonist hypnotic, has been shown to induce paradoxical responses in some patients with disorders of consciousness (DOC), leading to recovery of arousal and cognitive abilities. We here assessed zolpidem-induced changes in regional brain metabolism in three patients with known zolpidem response in chronic post-anoxic minimally conscious state (MCS). Methods: [18F]-fluorodeoxyglucose positron emission tomography (FDG-PET) and standardized clinical assessments using the Coma Recovery Scale-Revised were performed after administration of 10 mg zolpidem or placebo in a randomized double blind 2-day protocol. PET data preprocessing and comparison with a healthy age-matched control group were performed using statistical parametric mapping (SPM8). Results: Behaviorally, all patients recovered functional communication after administration of zolpidem (i.e., emergence from the MCS). FDG-PET showed increased metabolism in dorsolateral prefrontal and mesiofrontal cortices after zolpidem but not after placebo administration. Conclusion: Our data show a metabolic activation of prefrontal areas, corroborating the proposed mesocircuit hypothesis to explain the paradoxical effect of zolpidem observed in some patients with DOC. It also suggests the key role of the prefrontal cortices in the recovery of functional communication and object use in hypoxic patients with chronic MCS. PMID:25520636

Demography of Symbiotic Nitrogen-Fixing Trees Explains Their Rarity and Successional Decline in Temperate Forests in the United States

PubMed Central

Liao, Wenying; Menge, Duncan N. L.

2016-01-01

Symbiotic nitrogen (N) fixation is the major N input to many ecosystems. Although temperate forests are commonly N limited, symbiotic N-fixing trees (“N fixers”) are rare and decline in abundance as succession proceeds–a challenging paradox that remains unexplained. Understanding demographic processes that underlie N fixers’ rarity and successional decline would provide a proximate answer to the paradox. Do N fixers grow slower, die more frequently, or recruit less in temperate forests? We quantified demographic rates of N-fixing and non-fixing trees across succession using U.S. forest inventory data. We used an individual-based model to evaluate the relative contribution of each demographic process to community dynamics. Compared to non-fixers, N fixers had lower growth rates, higher mortality rates, and lower recruitment rates throughout succession. The mortality effect contributed more than the growth effect to N fixers’ successional decline. Canopy and understory N fixers experienced these demographic disadvantages, indicating that factors in addition to light limitation likely contribute to N fixers’ successional decline. We show that the rarity and successional decline of N-fixing trees in temperate forests is due more to their survival disadvantage than their growth disadvantage, and a recruitment disadvantage might also play a large role. PMID:27780268

Selection on skewed characters and the paradox of stasis.

PubMed

Bonamour, Suzanne; Teplitsky, Céline; Charmantier, Anne; Crochet, Pierre-André; Chevin, Luis-Miguel

2017-11-01

Observed phenotypic responses to selection in the wild often differ from predictions based on measurements of selection and genetic variance. An overlooked hypothesis to explain this paradox of stasis is that a skewed phenotypic distribution affects natural selection and evolution. We show through mathematical modeling that, when a trait selected for an optimum phenotype has a skewed distribution, directional selection is detected even at evolutionary equilibrium, where it causes no change in the mean phenotype. When environmental effects are skewed, Lande and Arnold's (1983) directional gradient is in the direction opposite to the skew. In contrast, skewed breeding values can displace the mean phenotype from the optimum, causing directional selection in the direction of the skew. These effects can be partitioned out using alternative selection estimates based on average derivatives of individual relative fitness, or additive genetic covariances between relative fitness and trait (Robertson-Price identity). We assess the validity of these predictions using simulations of selection estimation under moderate sample sizes. Ecologically relevant traits may commonly have skewed distributions, as we here exemplify with avian laying date - repeatedly described as more evolutionarily stable than expected - so this skewness should be accounted for when investigating evolutionary dynamics in the wild. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

Predator interference effects on biological control: The "paradox" of the generalist predator revisited

NASA Astrophysics Data System (ADS)

Parshad, Rana D.; Bhowmick, Suman; Quansah, Emmanuel; Basheer, Aladeen; Upadhyay, Ranjit Kumar

2016-10-01

An interesting conundrum in biological control questions the efficiency of generalist predators as biological control agents. Theory suggests, generalist predators are poor agents for biological control, primarily due to mutual interference. However field evidence shows they are actually quite effective in regulating pest densities. In this work we provide a plausible answer to this paradox. We analyze a three species model, where a generalist top predator is introduced into an ecosystem as a biological control, to check the population of a middle predator, that in turn is depredating on a prey species. We show that the inclusion of predator interference alone, can cause the solution of the top predator equation to blow-up in finite time, while there is global existence in the no interference case. This result shows that interference could actually cause a population explosion of the top predator, enabling it to control the target species, thus corroborating recent field evidence. Our results might also partially explain the population explosion of certain species, introduced originally for biological control purposes, such as the cane toad (Bufo marinus) in Australia, which now functions as a generalist top predator. We also show both Turing instability and spatio-temporal chaos in the model. Lastly we investigate time delay effects.

The moral status of the embryo: an attempt at an analysis with the aid of David Hume's ethics.

PubMed

Engel, J B; Hönig, A; Segerer, S; Häusler, S F M; Dietl, J; Djakovic, A

2010-12-01

This article applies the moral sentimentalism founded by David Hume to the moral status of the embryo. It will attempt to explain the paradoxical fact that in Germany abortion is common and socially accepted while preimplantation genetic diagnosis is banned with the aid of an approach based on moral sentimentalism. David Hume established the thesis that the human being is guided by the emotions and not by reason when making moral decisions. Scientific innovations often create a feeling of anxiety. Consequently, the initial moral judgment about it is negative. Due to this habit, the innovation is often accepted after a phase of indifference. This phenomenon has been observed in the case of heart transplantation, as well as for IVF. Consequently, the apparent contradiction in the varying degrees of the embryo's worthiness of protection in the womb and in the Petri dish is due to the simple fact that these are different stages of habituation. Therefore, the ethics of Hume cannot stipulate the embryo's moral status for once and for all; however, they can paradoxically raise the ongoing current debate to a more rational level through the insight that the underlying moral concepts are not based on reason alone. Copyright © 2010 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

The impact of physical impairment on emotional well-being in ALS.

PubMed

Abdulla, Susanne; Vielhaber, Stefan; Kollewe, Katja; Machts, Judith; Heinze, Hans-Jochen; Dengler, Reinhard; Petri, Susanne

2014-09-01

There has been evidence that subjective quality of life in patients with amyotrophic lateral sclerosis (ALS) is comparatively good, unrelated to the state of physical functioning, so called 'disability paradox'. Other studies show weak to moderate correlations between disease severity and emotional well-being. Our aim was to analyse the impact of physical impairment on emotional well-being when assessed disease-specifically and seen through the patient's eyes with additional clinical evaluation. In 121 patients emotional functioning was evaluated by the ALS Assessment Questionnaire (ALSAQ-40). Physical status was assessed by the ALS Functional Rating Scale-Extension (ALSFRS-EX) and Borg dyspnoea scales and by clinical examination (muscle strength and pulmonary function). Multiple regression and correlation analyses were performed. Results showed that physical impairment and progression rate of physical deterioration had a significant impact and explained some variance in emotional well-being (adjusted R(2) = 0.22). Pulmonary function and the sense of dyspnoea correlated significantly on a weak to moderate level with emotional well-being. In conclusion, disease-specific patient- reported outcome measurement instruments revealed a moderate but distinct impact of physical impairment on emotional well-being. This study challenges the 'disability paradox' and has relevant findings that can support the timely delivery of care for ALS patients.

Modern Fysics Phallacies: The Best Way Not to Unify Physics

NASA Astrophysics Data System (ADS)

Beichler, James E.

Too many physicists believe the `phallacy' that the quantum is more fundamental than relativity without any valid supporting evidence, so the earliest attempts to unify physics based on the continuity of relativity have been all but abandoned. This belief is probably due to the wealth of pro-quantum propaganda and general `phallacies in fysics' that were spread during the second quarter of the twentieth century, although serious `phallacies' exist throughout physics on both sides of the debate. Yet both approaches are basically flawed because both relativity and the quantum theory are incomplete and grossly misunderstood as they now stand. Had either side of the quantum versus relativity controversy sought common ground between the two worldviews, total unification would have been accomplished long ago. The point is, literally, that the discrete quantum, continuous relativity, basic physical geometry, theoretical mathematics and classical physics all share one common characteristic that has never been fully explored or explained - a paradoxical duality between a dimensionless point (discrete) and an extended length (continuity) in any dimension - and if the problem of unification is approached from an understanding of how this paradox relates to each paradigm, all of physics and indeed all of science could be unified under a single new theoretical paradigm.

Exploring Risk Factors in Latino Cardiovascular Disease: The Role of Education, Nativity, and Gender

PubMed Central

Zambrana, Ruth E.; Garza, Mary A.

2014-01-01

Objectives. We examined 3 cardiovascular disease risk factors by nativity and gender, evaluating evidence for education and health behaviors in explaining the “Hispanic Health Paradox.” Methods. We analyzed 2001–2008 National Health and Nutrition Examination Survey data for adults (n = 6032) to compare hypertension, high waist circumference, and diabetes for US- and foreign-born Mexican men and women. We controlled for age, depression, and health insurance. Results. Cardiovascular disease risk factors differed by education, nativity, and gender. Higher education was associated with higher odds of hypertension and high waist circumference for men and women regardless of nativity. As education increased, the odds of diabetes increased for US-born women, showing a gradient for this population. Finally, foreign-born Mexican women with 5 to 19 years in the United States conferred the highest odds of having diabetes, whereas foreign-born men with less than 5 years in the United States had the lowest odds for high waist circumference and presence of diabetes. Conclusions. Results contest assumptions of the Hispanic Health Paradox and suggest new approaches. New research can yield accurate information to ensure the development of appropriate interventions, decreasing health disparities endemic to a subgroup of Latinos. PMID:24028268

Gliding flight: drag and torque of a hawk and a falcon with straight and turned heads, and a lower value for the parasite drag coefficient.

PubMed

Tucker, V A

2000-12-01

Raptors - falcons, hawks and eagles in this study - such as peregrine falcons (Falco peregrinus) that attack distant prey from high-speed dives face a paradox. Anatomical and behavioral measurements show that raptors of many species must turn their heads approximately 40 degrees to one side to see the prey straight ahead with maximum visual acuity, yet turning the head would presumably slow their diving speed by increasing aerodynamic drag. This paper investigates the aerodynamic drag part of this paradox by measuring the drag and torque on wingless model bodies of a peregrine falcon and a red-tailed hawk (Buteo jamaicensis) with straight and turned heads in a wind tunnel at a speed of 11.7 m s(-)(1). With a turned head, drag increased more than 50 %, and torque developed that tended to yaw the model towards the direction in which the head pointed. Mathematical models for the drag required to prevent yawing showed that the total drag could plausibly more than double with head-turning. Thus, the presumption about increased drag in the paradox is correct. The relationships between drag, head angle and torque developed here are prerequisites to the explanation of how a raptor could avoid the paradox by holding its head straight and flying along a spiral path that keeps its line of sight for maximum acuity pointed sideways at the prey. Although the spiral path to the prey is longer than the straight path, the raptor's higher speed can theoretically compensate for the difference in distances; and wild peregrines do indeed approach prey by flying along curved paths that resemble spirals. In addition to providing data that explain the paradox, this paper reports the lowest drag coefficients yet measured for raptor bodies (0.11 for the peregrine and 0.12 for the red-tailed hawk) when the body models with straight heads were set to pitch and yaw angles for minimum drag. These values are markedly lower than value of the parasite drag coefficient (C(D,par)) of 0.18 previously used for calculating the gliding performance of a peregrine. The accuracy with which drag coefficients measured on wingless bird bodies in a wind tunnel represent the C(D,par) of a living bird is unknown. Another method for determining C(D,par) selects values that improve the fit between speeds predicted by mathematical models and those observed in living birds. This method yields lower values for C(D,par) (0.05-0.07) than wind tunnel measurements, and the present study suggests a value of 0.1 for raptors as a compromise.

Zeno Meets Modern Science

NASA Astrophysics Data System (ADS)

Silagadze, Z. K.

2005-10-01

``No one has ever touched Zeno without refuting him''. We will not refute Zeno in this paper. Instead we review some unexpected encounters of Zeno with modern science. The paper begins with a brief biography of Zeno of Elea followed by his famous paradoxes of motion. Reflections on continuity of space and time lead us to Banach and Tarski and to their celebrated paradox, which is in fact not a paradox at all but a strict mathematical theorem, although very counterintuitive. Quantum mechanics brings another flavour in Zeno paradoxes. Quantum Zeno and anti-Zeno effects are really paradoxical but now experimental facts. Then we discuss supertasks and bifurcated supertasks. The concept of localisation leads us to Newton and Wigner and to interesting phenomenon of quantum revivals. At last we note that the paradoxical idea of timeless universe, defended by Zeno and Parmenides at ancient times, is still alive in quantum gravity. The list of references that follows is necessarily incomplete but we hope it will assist interested reader to fill in details.

Navigating Instructional Dialectics: Empirical Exploration of Paradox in Teaching

ERIC Educational Resources Information Center

Thompson, Blair; Rudick, C. Kyle; Kerssen-Griep, Jeff; Golsan, Kathryn

2018-01-01

Navigating contradiction represents an integral part of the teaching process. While educational literature has discussed the paradoxes that teachers experience in the classroom, minimal empirical research has analyzed the strategies teachers employ to address these paradoxes. Using relational dialectics as a theoretical framework for understanding…

Water flux management and phytoplankton communities in a Mediterranean coastal lagoon. Part II: Mixotrophy of dinoflagellates as an adaptive strategy?

PubMed

Cecchi, P; Garrido, M; Collos, Y; Pasqualini, V

2016-07-15

Dinoflagellate proliferation is common in coastal waters, and trophic strategies are often advanced to explain the success of these organisms. The Biguglia lagoon is a Mediterranean brackish ecosystem where eutrophication has long been an issue, and where dominance of dinoflagellates has persisted for several years. Monthly monitoring of fluorescence-based properties of phytoplankton communities carried out in 2010 suggested that photosynthesis alone could not support the observed situation all year round. Contrasting food webs developed depending on the hydrological season, with a gradual shift from autotrophy to heterotrophy. Progressively, microphytoplankton assemblages became unequivocally dominated by a Prorocentrum minimum bloom, which exhibited very weak effective photosynthetic performance, whereas paradoxically its theoretical capacities remained fully operational. Different environmental hypotheses explaining this discrepancy were examined, but rejected. We conclude that P. minimum bloom persistence is sustained by mixotrophic strategies, with complex compromises between phototrophy and phagotrophy, as evidenced by fluorescence-based observations. Copyright © 2016 Elsevier Ltd. All rights reserved.

Collective behavior of brain tumor cells: The role of hypoxia

NASA Astrophysics Data System (ADS)

Khain, Evgeniy; Katakowski, Mark; Hopkins, Scott; Szalad, Alexandra; Zheng, Xuguang; Jiang, Feng; Chopp, Michael

2011-03-01

We consider emergent collective behavior of a multicellular biological system. Specifically, we investigate the role of hypoxia (lack of oxygen) in migration of brain tumor cells. We performed two series of cell migration experiments. In the first set of experiments, cell migration away from a tumor spheroid was investigated. The second set of experiments was performed in a typical wound-healing geometry: Cells were placed on a substrate, a scratch was made, and cell migration into the gap was investigated. Experiments show a surprising result: Cells under normal and hypoxic conditions have migrated the same distance in the “spheroid” experiment, while in the “scratch” experiment cells under normal conditions migrated much faster than under hypoxic conditions. To explain this paradox, we formulate a discrete stochastic model for cell dynamics. The theoretical model explains our experimental observations and suggests that hypoxia decreases both the motility of cells and the strength of cell-cell adhesion. The theoretical predictions were further verified in independent experiments.

Preference reversal in quantum decision theory.

PubMed

Yukalov, Vyacheslav I; Sornette, Didier

2015-01-01

We consider the psychological effect of preference reversal and show that it finds a natural explanation in the frame of quantum decision theory. When people choose between lotteries with non-negative payoffs, they prefer a more certain lottery because of uncertainty aversion. But when people evaluate lottery prices, e.g., for selling to others the right to play them, they do this more rationally, being less subject to behavioral biases. This difference can be explained by the presence of the attraction factors entering the expression of quantum probabilities. Only the existence of attraction factors can explain why, considering two lotteries with close utility factors, a decision maker prefers one of them when choosing, but evaluates higher the other one when pricing. We derive a general quantitative criterion for the preference reversal to occur that relates the utilities of the two lotteries to the attraction factors under choosing vs. pricing and test successfully its application on experiments by Tversky et al. We also show that the planning paradox can be treated as a kind of preference reversal.

The Missing Mantle Paradox, and the Statistical Argument for Repeated Hit and Run Collisions

NASA Astrophysics Data System (ADS)

Asphaug, E.; Reufer, A.

2015-10-01

Mercury's formation can be explained by a giant impact. However, a direct hit blasting off the mantle [1] leaves debris stranded in orbitabout the Sun,to be re-accumulated back onto Mercury. A hit and run collision [2] provides a cleaner solution, and in most cases,much lower levels of shock and potentially greater retention of volatiles. However, hit and run is usually followed by subsequent re-collision, and ultimate accretion; an embryo's survival after being a hit and run projectile is unlikely in any single instance. Most of the original planetary embryoshave been accreted by Earth and Venus; unaccreted planets are lucky. Here we show that the surviving terrestrial planet population is likely to have about as many hit and run survivors, as it is to have untouched survivors. That is, the differences between Mercury and Mars can be explained in a statistical manner as a consequence of accretionary attrition. We consider applications to asteroids, meteorites and exoplanets.

The Aviation Paradox: Why We Can 'Know' Jetliners But Not Reactors.

PubMed

Downer, John

2017-01-01

Publics and policymakers increasingly have to contend with the risks of complex, safety-critical technologies, such as airframes and reactors. As such, 'technological risk' has become an important object of modern governance, with state regulators as core agents, and 'reliability assessment' as the most essential metric. The Science and Technology Studies (STS) literature casts doubt on whether or not we should place our faith in these assessments because predictively calculating the ultra-high reliability required of such systems poses seemingly insurmountable epistemological problems. This paper argues that these misgivings are warranted in the nuclear sphere, despite evidence from the aviation sphere suggesting that such calculations can be accurate. It explains why regulatory calculations that predict the reliability of new airframes cannot work in principle, and then it explains why those calculations work in practice. It then builds on this explanation to argue that the means by which engineers manage reliability in aviation is highly domain-specific, and to suggest how a more nuanced understanding of jetliners could inform debates about nuclear energy.

Beyond parental control and authoritarian parenting style: understanding Chinese parenting through the cultural notion of training.

PubMed

Chao, R K

1994-08-01

This study addresses a paradox in the literature involving the parenting style of Asians: Chinese parenting has often been described as "controlling" or "authoritarian". These styles of parenting have been found to be predictive of poor school achievement among European-Americans, and yet the Chinese are performing quite well in school. This study suggests that the concepts of authoritative and authoritarian are somewhat ethnocentric and do not capture the important features of Chinese child rearing, especially for explaining their school success. Immigrant Chinese and European-American mothers of preschool-aged children were administered standard measures of parental control and authoritative-authoritarian parenting style as well as Chinese child-rearing items involving the concept of "training." After controlling for their education, and their scores on the standard measures, the Chinese mothers were found to score significantly higher on the "training" ideologies. This "training" concept has important features, beyond the authoritarian concept, that may explain Chinese school success.

Socioeconomic dynamics of water quality in the Egyptian Nile

NASA Astrophysics Data System (ADS)

Malik, Maheen; Nisar, Zainab; Karakatsanis, Georgios

2016-04-01

The Nile River remains the most important source of freshwater for Egypt as it accounts for nearly all of the country's drinking and irrigation water. About 95% of the total population is accounted to live along the Banks of the Nile(1). Therefore, water quality deterioration in addition to general natural scarcity of water in the region(2) is the main driver for carrying out this study. What further aggravates this issue is the water conflict in the Blue Nile region. The study evaluates different water quality parameters and their concentrations in the Egyptian Nile; further assessing the temporal dynamics of water quality in the area with (a) the Environmental Kuznets Curve (EKC)(3) and (b) the Jevons Paradox (JP)(4) in order to identify water quality improvements or degradations using selected socioeconomic variables(5). For this purpose various environmental indicators including BOD, COD, DO, Phosphorus and TDS were plotted against different economic variables including Population, Gross Domestic Product (GDP), Annual Fresh Water Withdrawal and Improved Water Source. Mathematically, this was expressed by 2nd and 3rd degree polynomial regressions generating the EKC and JP respectively. The basic goal of the regression analysis is to model and highlight the dynamic trend of water quality indicators in relation to their established permissible limits, which will allow the identification of optimal future water quality policies. The results clearly indicate that the dependency of water quality indicators on socioeconomic variables differs for every indicator; while COD was above the permissible limits in all the cases despite of its decreasing trend in each case, BOD and phosphate signified increasing concentrations for the future, if they continue to follow the present trend. This could be an indication of rebound effect explained by the Jevons Paradox i.e. water quality deterioration after its improvement, either due to increase of population or intensification of economic activities related to these indicators. Keywords: Water quality dynamics, Environmental Kuznets Curve (EKC), Jevons Paradox (JP), economic variables, polynomial regressions, environmental indicators, permissible limit References: (1)Evans, A. (2007). River of Life River Nile. (2)Egypt's Water Crisis - Recipe for Disaster. (2016). [Blog] EcoMENA- Echoing Sustainability. (3)Alstine, J. and Neumayer, E. (2010). The Environmental Kuznets Curve. (4)Garrett, T. (2014). Rebound, Backfire, and the Jevons Paradox. [Blog] (5)Data.worldbank.org

Central adiposity and the overweight risk paradox in aging: follow-up of 130,473 UK Biobank participants.

PubMed

Bowman, Kirsty; Atkins, Janice L; Delgado, João; Kos, Katarina; Kuchel, George A; Ble, Alessandro; Ferrucci, Luigi; Melzer, David

2017-07-01

Background: For older groups, being overweight [body mass index (BMI; in kg/m 2 ): 25 to <30] is reportedly associated with a lower or similar risk of mortality than being normal weight (BMI: 18.5 to <25). However, this "risk paradox" is partly explained by smoking and disease-associated weight loss. This paradox may also arise from BMI failing to measure fat redistribution to a centralized position in later life. Objective: This study aimed to estimate associations between combined measurements of BMI and waist-to-hip ratio (WHR) with mortality and incident coronary artery disease (CAD). Design: This study followed 130,473 UK Biobank participants aged 60-69 y (baseline 2006-2010) for ≤8.3 y ( n = 2974 deaths). Current smokers and individuals with recent or disease-associated (e.g., from dementia, heart failure, or cancer) weight loss were excluded, yielding a "healthier agers" group. Survival models were adjusted for age, sex, alcohol intake, smoking history, and educational attainment. Population and sex-specific lower and higher WHR tertiles were <0.91 and ≥0.96 for men and <0.79 and ≥0.85 for women, respectively. Results: Ignoring WHR, the risk of mortality for overweight subjects was similar to that for normal-weight subjects (HR: 1.09; 95% CI: 0.99, 1.19; P = 0.066). However, among normal-weight subjects, mortality increased for those with a higher WHR (HR: 1.33; 95% CI: 1.08, 1.65) compared with a lower WHR. Being overweight with a higher WHR was associated with substantial excess mortality (HR: 1.41; 95% CI: 1.25, 1.61) and greatly increased CAD incidence (sub-HR: 1.64; 95% CI: 1.39, 1.93) compared with being normal weight with a lower WHR. There was no interaction between physical activity and BMI plus WHR groups with respect to mortality. Conclusions: For healthier agers (i.e., nonsmokers without disease-associated weight loss), having central adiposity and a BMI corresponding to normal weight or overweight is associated with substantial excess mortality. The claimed BMI-defined overweight risk paradox may result in part from failing to account for central adiposity, rather than reflecting a protective physiologic effect of higher body-fat content in later life.

Losing Stuff Down a Black Hole

NASA Astrophysics Data System (ADS)

Okon, Elias; Sudarsky, Daniel

2018-03-01

Over the years, the so-called black hole information loss paradox has generated an amazingly diverse set of (often radical) proposals. However, 40 years after the introduction of Hawking's radiation, there continues to be a debate regarding whether the effect does, in fact, lead to an actual problem. In this paper we try to clarify some aspect of the discussion by describing two possible perspectives regarding the landscape of the information loss issue. Moreover, we advance a fairly conservative point of view regarding the relation between evaporating black holes and the rest of physics, which leads us to advocate a generalized breakdown of unitarity. We conclude by exploring some implications of our proposal in relation with conservation laws.

First Impressions From Faces

PubMed Central

Zebrowitz, Leslie A

2016-01-01

Although cultural wisdom warns ‘don’t judge a book by its cover,’ we seem unable to inhibit this tendency even though it can produce inaccurate impressions of people’s psychological traits and has significant social consequences. One explanation for this paradox is that first impressions of faces overgeneralize our adaptive impressions of categories of people that those faces resemble (including babies, familiar or unfamiliar people, unfit people, emotional people). Research testing these ‘overgeneralization’ hypotheses elucidates why we form first impressions from faces, what impressions we form, and what cues influence these impressions. This article focuses on commonalities in impressions across diverse perceivers. However, brief attention is given to individual differences in impressions and impression accuracy. PMID:28630532

Paradox in AI - AI 2.0: The Way to Machine Consciousness

NASA Astrophysics Data System (ADS)

Palensky, Peter; Bruckner, Dietmar; Tmej, Anna; Deutsch, Tobias

Artificial Intelligence, the big promise of the last millennium, has apparently made its way into our daily lives. Cell phones with speech control, evolutionary computing in data mining or power grids, optimized via neural network, show its applicability in industrial environments. The original expectation of true intelligence and thinking machines lies still ahead of us. Researchers are, however, optimistic as never before. This paper tries to compare the views, challenges and approaches of several disciplines: engineering, psychology, neuroscience, philosophy. It gives a short introduction to Psychoanalysis, discusses the term consciousness, social implications of intelligent machines, related theories, and expectations and shall serve as a starting point for first attempts of combining these diverse thoughts.

Genetic diversity is largely unpredictable but scales with museum occurrences in a species-rich clade of Australian lizards

PubMed Central

Huang, Huateng; Title, Pascal O.; Donnellan, Stephen C.; Holmes, Iris; Rabosky, Daniel L.

2017-01-01

Genetic diversity is a fundamental characteristic of species and is affected by many factors, including mutation rate, population size, life history and demography. To better understand the processes that influence levels of genetic diversity across taxa, we collected genome-wide restriction-associated DNA data from more than 500 individuals spanning 76 nominal species of Australian scincid lizards in the genus Ctenotus. To avoid potential biases associated with variation in taxonomic practice across the group, we used coalescent-based species delimitation to delineate 83 species-level lineages within the genus for downstream analyses. We then used these genetic data to infer levels of within-population genetic diversity. Using a phylogenetically informed approach, we tested whether variation in genetic diversity could be explained by population size, environmental heterogeneity or historical demography. We find that the strongest predictor of genetic diversity is a novel proxy for census population size: the number of vouchered occurrences in museum databases. However, museum occurrences only explain a limited proportion of the variance in genetic diversity, suggesting that genetic diversity might be difficult to predict at shallower phylogenetic scales. PMID:28469025

Genetic diversity is largely unpredictable but scales with museum occurrences in a species-rich clade of Australian lizards.

PubMed

Singhal, Sonal; Huang, Huateng; Title, Pascal O; Donnellan, Stephen C; Holmes, Iris; Rabosky, Daniel L

2017-05-17

Genetic diversity is a fundamental characteristic of species and is affected by many factors, including mutation rate, population size, life history and demography. To better understand the processes that influence levels of genetic diversity across taxa, we collected genome-wide restriction-associated DNA data from more than 500 individuals spanning 76 nominal species of Australian scincid lizards in the genus Ctenotus To avoid potential biases associated with variation in taxonomic practice across the group, we used coalescent-based species delimitation to delineate 83 species-level lineages within the genus for downstream analyses. We then used these genetic data to infer levels of within-population genetic diversity. Using a phylogenetically informed approach, we tested whether variation in genetic diversity could be explained by population size, environmental heterogeneity or historical demography. We find that the strongest predictor of genetic diversity is a novel proxy for census population size: the number of vouchered occurrences in museum databases. However, museum occurrences only explain a limited proportion of the variance in genetic diversity, suggesting that genetic diversity might be difficult to predict at shallower phylogenetic scales. © 2017 The Author(s).

Anthropogenic-based regional-scale factors most consistently explain plot-level exotic diversity in grasslands

USDA-ARS?s Scientific Manuscript database

Invasion is viewed as a dominant threat to Earth’s biological diversity, but evidence linking the accumulation of exotic species to the simultaneous suppression of native diversity is equivocal, relying heavily on data from studies using different methods and designs. Fine-scale studies often descr...

The Chinese Classroom Paradox: A Cross-Cultural Comparison of Teacher Controlling Behaviors

ERIC Educational Resources Information Center

Zhou, Ning; Lam, Shui-Fong; Chan, Kam Chi

2012-01-01

Chinese classrooms present an intriguing paradox to the claim of self-determination theory that autonomy facilitates learning. Chinese teachers appear to be controlling, but Chinese students do not have poor academic performance in international comparisons. The present study addressed this paradox by examining the cultural differences in…

New Paradoxes of Risky Decision Making

ERIC Educational Resources Information Center

Birnbaum, Michael H.

2008-01-01

During the last 25 years, prospect theory and its successor, cumulative prospect theory, replaced expected utility as the dominant descriptive theories of risky decision making. Although these models account for the original Allais paradoxes, 11 new paradoxes show where prospect theories lead to self-contradiction or systematic false predictions.…

Virtue Acquisition: The Paradox of Striving

ERIC Educational Resources Information Center

Snow, Nancy

2016-01-01

Aristotelian-inspired accounts of virtue acquisition stress guided practice and habituated action to develop virtue. This emphasis on action can lead to the "paradox of striving". The paradox occurs when we try too hard to act well and thereby spoil our efforts. I identify four forms of striving--forcing, impulsivity, overthinking, and…

Paradox and Double Binds in Adventure-Based Education.

ERIC Educational Resources Information Center

Bacon, Stephen Barcia

Paradox and therapeutic double bind techniques are used to overcome resistance in students with a history of success avoidance. Predictions of failure, restraining comments, and the use of paradox in the midst of an activity are defended theoretically by presenting historical roots and a rationale of effectiveness. A skill-building approach…

A new transport phenomenon in nanostructures: a mesoscopic analog of the Braess paradox encountered in road networks

PubMed Central

2012-01-01

The Braess paradox, known for traffic and other classical networks, lies in the fact that adding a new route to a congested network in an attempt to relieve congestion can degrade counterintuitively the overall network performance. Recently, we have extended the concept of the Braess paradox to semiconductor mesoscopic networks, whose transport properties are governed by quantum physics. In this paper, we demonstrate theoretically that, alike in classical systems, congestion plays a key role in the occurrence of a Braess paradox in mesoscopic networks. PMID:22913510

Paradoxical response preceding control of Scedosporium apiospermum mycetoma with posaconazole treatment.

PubMed

Béraud, Guillaume; Desbois, Nicole; Coyo, Caroline; Quist, Danièle; Rozé, Benoit; Savorit, Luc; Cabié, André

2015-01-01

Mycetoma is a chronic granulomatous infection that is difficult to treat, notably when due to fungi such as Scedosporium apiospermum. Recent antifungal agents could be an option, but cases are rarely reported, and none with posaconazole. Paradoxical responses, defined as initial clinical worsening despite appropriate treatment, are common in tuberculosis but rare in deep mycoses in non-immunocompromised hosts. Hence, paradoxical responses in context other than mycobacterial infection in an immunocompromised host could provide insights into the pathophysiology and the optimal strategy for treatment. We report the first case of a mycetoma caused by S. apiospermum with bone involvement treated with posaconazole, and the paradoxical response observed at the beginning of the treatment. As with mycobacterial infections, a paradoxical response in deep mycosis could represent the earliest marker of therapeutic efficacy.

Patent foramen ovale and paradoxical embolization: a historical perspective.

PubMed

Lippmann, H; Rafferty, T

1993-01-01

The use of transesophageal echocardiography for intraoperative management of critically ill patients allows for routine evaluation of foramen ovale patency. The high prevalence of preoperatively unrecognized flow-patency of this structure has led investigators to emphasize the potential for paradoxical embolization in any patient undergoing anesthesia. This perspective led us to research earliest documentation of paradoxical embolization through a patent foramen ovale as a historical issue with present day relevance. This report examines the 1877 text of Julius Cohnheim in which he described a fatal case of paradoxical embolization to the middle meningeal artery. The 1880 manuscript of Moritz Litten documenting paradoxical embolization to the lower extremity is also presented. Both translations, to our knowledge, represent the first such representations of both the original 1877 edition of Cohnheim's work and Litten's journal article.

Parrondo's games based on complex networks and the paradoxical effect.

PubMed

Ye, Ye; Wang, Lu; Xie, Nenggang

2013-01-01

Parrondo's games were first constructed using a simple tossing scenario, which demonstrates the following paradoxical situation: in sequences of games, a winning expectation may be obtained by playing the games in a random order, although each game (game A or game B) in the sequence may result in losing when played individually. The available Parrondo's games based on the spatial niche (the neighboring environment) are applied in the regular networks. The neighbors of each node are the same in the regular graphs, whereas they are different in the complex networks. Here, Parrondo's model based on complex networks is proposed, and a structure of game B applied in arbitrary topologies is constructed. The results confirm that Parrondo's paradox occurs. Moreover, the size of the region of the parameter space that elicits Parrondo's paradox depends on the heterogeneity of the degree distributions of the networks. The higher heterogeneity yields a larger region of the parameter space where the strong paradox occurs. In addition, we use scale-free networks to show that the network size has no significant influence on the region of the parameter space where the strong or weak Parrondo's paradox occurs. The region of the parameter space where the strong Parrondo's paradox occurs reduces slightly when the average degree of the network increases.

The fermi paradox is neither Fermi's nor a paradox.

PubMed

Gray, Robert H

2015-03-01

The so-called Fermi paradox claims that if technological life existed anywhere else, we would see evidence of its visits to Earth--and since we do not, such life does not exist, or some special explanation is needed. Enrico Fermi, however, never published anything on this topic. On the one occasion he is known to have mentioned it, he asked "Where is everybody?"--apparently suggesting that we do not see extraterrestrials on Earth because interstellar travel may not be feasible, but not suggesting that intelligent extraterrestrial life does not exist or suggesting its absence is paradoxical. The claim "they are not here; therefore they do not exist" was first published by Michael Hart, claiming that interstellar travel and colonization of the Galaxy would be inevitable if intelligent extraterrestrial life existed, and taking its absence here as proof that it does not exist anywhere. The Fermi paradox appears to originate in Hart's argument, not Fermi's question. Clarifying the origin of these ideas is important, because the Fermi paradox is seen by some as an authoritative objection to searching for evidence of extraterrestrial intelligence--cited in the U.S. Congress as a reason for killing NASA's SETI program on one occasion. But evidence indicates that it misrepresents Fermi's views, misappropriates his authority, deprives the actual authors of credit, and is not a valid paradox.

Climate-driven range shifts explain the distribution of extant gene pools and predict future loss of unique lineages in a marine brown alga.

PubMed

Assis, J; Serrão, E A; Claro, B; Perrin, C; Pearson, G A

2014-06-01

The climate-driven dynamics of species ranges is a critical research question in evolutionary ecology. We ask whether present intraspecific diversity is determined by the imprint of past climate. This is an ongoing debate requiring interdisciplinary examination of population genetic pools and persistence patterns across global ranges. Previously, contrasting inferences and predictions have resulted from distinct genomic coverage and/or geographical information. We aim to describe and explain the causes of geographical contrasts in genetic diversity and their consequences for the future baseline of the global genetic pool, by comparing present geographical distribution of genetic diversity and differentiation with predictive species distribution modelling (SDM) during past extremes, present time and future climate scenarios for a brown alga, Fucus vesiculosus. SDM showed that both atmospheric and oceanic variables shape the global distribution of intertidal species, revealing regions of persistence, extinction and expansion during glacial and postglacial periods. These explained the distribution and structure of present genetic diversity, consisting of differentiated genetic pools with maximal diversity in areas of long-term persistence. Most of the present species range comprises postglacial expansion zones and, in contrast to highly dispersive marine organisms, expansions involved only local fronts, leaving distinct genetic pools at rear edges. Besides unravelling a complex phylogeographical history and showing congruence between genetic diversity and persistent distribution zones, supporting the hypothesis of niche conservatism, range shifts and loss of unique genetic diversity at the rear edge were predicted for future climate scenarios, impoverishing the global gene pool. © 2014 John Wiley & Sons Ltd.

Figurative language processing in atypical populations: the ASD perspective

PubMed Central

Vulchanova, Mila; Saldaña, David; Chahboun, Sobh; Vulchanov, Valentin

2015-01-01

This paper is intended to provide a critical overview of experimental and clinical research documenting problems in figurative language processing in atypical populations with a focus on the Autistic Spectrum. Research in the comprehension and processing of figurative language in autism invariably documents problems in this area. The greater paradox is that even at the higher end of the spectrum or in the cases of linguistically talented individuals with Asperger syndrome, where structural language competence is intact, problems with extended language persist. If we assume that figurative and extended uses of language essentially depend on the perception and processing of more concrete core concepts and phenomena, the commonly observed failure in atypical populations to understand figurative language remains a puzzle. Various accounts have been offered to explain this issue, ranging from linking potential failure directly to overall structural language competence (Norbury, 2005; Brock et al., 2008) to right-hemispheric involvement (Gold and Faust, 2010). We argue that the dissociation between structural language and figurative language competence in autism should be sought in more general cognitive mechanisms and traits in the autistic phenotype (e.g., in terms of weak central coherence, Vulchanova et al., 2012b), as well as failure at on-line semantic integration with increased complexity and diversity of the stimuli (Coulson and Van Petten, 2002). This perspective is even more compelling in light of similar problems in a number of conditions, including both acquired (e.g., Aphasia) and developmental disorders (Williams Syndrome). This dissociation argues against a simple continuity view of language interpretation. PMID:25741261

Figurative language processing in atypical populations: the ASD perspective.

PubMed

Vulchanova, Mila; Saldaña, David; Chahboun, Sobh; Vulchanov, Valentin

2015-01-01

This paper is intended to provide a critical overview of experimental and clinical research documenting problems in figurative language processing in atypical populations with a focus on the Autistic Spectrum. Research in the comprehension and processing of figurative language in autism invariably documents problems in this area. The greater paradox is that even at the higher end of the spectrum or in the cases of linguistically talented individuals with Asperger syndrome, where structural language competence is intact, problems with extended language persist. If we assume that figurative and extended uses of language essentially depend on the perception and processing of more concrete core concepts and phenomena, the commonly observed failure in atypical populations to understand figurative language remains a puzzle. Various accounts have been offered to explain this issue, ranging from linking potential failure directly to overall structural language competence (Norbury, 2005; Brock et al., 2008) to right-hemispheric involvement (Gold and Faust, 2010). We argue that the dissociation between structural language and figurative language competence in autism should be sought in more general cognitive mechanisms and traits in the autistic phenotype (e.g., in terms of weak central coherence, Vulchanova et al., 2012b), as well as failure at on-line semantic integration with increased complexity and diversity of the stimuli (Coulson and Van Petten, 2002). This perspective is even more compelling in light of similar problems in a number of conditions, including both acquired (e.g., Aphasia) and developmental disorders (Williams Syndrome). This dissociation argues against a simple continuity view of language interpretation.

First Do No Harm: Euthanasia of Patients with Dementia in Belgium

PubMed Central

Cohen-Almagor, Raphael

2016-01-01

In Memory of Ed Pellegrino Euthanasia in Belgium is not limited to terminally ill patients. It may be applied to patients with chronic degenerative diseases. Currently, people in Belgium wish to make it possible to euthanize incompetent patients who suffer from dementia. This article explains the Belgian law and then explores arguments for and against euthanasia of patients with dementia. It probes the dementia paradox by elucidating Dworkin’s distinction between critical and experiential interests, arguing that at the end-of-life this distinction is not clearcut. It argues against euthanasia for patients with dementia, for respecting patients’ humanity and for providing them with more care, compassion, and good doctoring. PMID:26661050

Centromeres Drive a Hard Bargain

PubMed Central

Rosin, Leah F.; Mellone, Barbara G.

2017-01-01

Centromeres are essential chromosomal structures that mediate the accurate distribution of genetic material during meiotic and mitotic cell divisions. In most organisms, centromeres are epigenetically specified and propagated by nucleosomes containing the centromere-specific H3 variant, CENP-A. Although centromeres perform a critical and conserved function, CENP-A and the underlying centromeric DNA are rapidly evolving. This paradox has been explained by the centromere drive hypothesis, which proposes that CENP-A is undergoing an evolutionary tug-of-war with selfish centromeric DNA. Here, we review our current understanding of CENP-A evolution in relation to centromere drive and discuss classical and recent advances, including new evidence implicating CENP-A chaperones in this conflict. PMID:28069312

Unthermal charged massive Hawking radiation from a Reissner-Nordström-de Sitter black hole

NASA Astrophysics Data System (ADS)

Khayrul Hasan, M.

2015-05-01

We investigate the massive charged particles' Hawking radiation from a Reissner-Nordström-de Sitter (RNdS) black hole by Damour-Ruffini's method. We get the unthermal spectrum when the back-reaction of particles' energy and charge to spacetime is considered. The information will get out from the black hole with the corrected spectrum. The radiation is not exactly thermal and because the derivation obeys conservation laws, the non thermal Hawking radiation can carry information from the black hole. In our work the method is more simple and explicit and it can be used to explain the black hole information loss paradox, and the process satisfies underlying unitary theory.

Gushing metal chain

NASA Astrophysics Data System (ADS)

Belyaev, Alexander; Sukhanov, Alexander; Tsvetkov, Alexander

2016-03-01

This article addresses the problem in which a chain falls from a glass from some height. This phenomenon demonstrates a paradoxical rise of the chain over the glass. To explain this effect, an initial hypothesis and an appropriate theory are proposed for calculating the steady fall parameters of the chain. For this purpose, the modified Cayley's problem of falling chain given its rise due to the centrifugal force of upward inertia is solved. Results show that the lift caused by an increase in linear density at the part of chain where it is being bent (the upper part) is due to the convergence of the chain balls to one another. The experiments confirm the obtained estimates of the lifting chain.

Spatial sorting promotes the spread of maladaptive hybridization

USGS Publications Warehouse

Lowe, Winsor H.; Muhlfeld, Clint C.; Allendorf, Fred W.

2015-01-01

Invasive hybridization is causing loss of biodiversity worldwide. The spread of such introgression can occur even when hybrids have reduced Darwinian fitness, which decreases the frequency of hybrids due to low survival or reproduction through time. This paradox can be partially explained by spatial sorting, where genotypes associated with dispersal increase in frequency at the edge of expansion, fueling further expansion and allowing invasive hybrids to increase in frequency through space rather than time. Furthermore, because all progeny of a hybrid will be hybrids (i.e., will possess genes from both parental taxa), nonnative admixture in invaded populations can increase even when most hybrid progeny do not survive. Broader understanding of spatial sorting is needed to protect native biodiversity.

Economic Growth Evens Out Happiness: Evidence from Six Surveys

PubMed Central

Clark, Andrew E.; Flèche, Sarah; Senik, Claudia

2015-01-01

In spite of the great U-turn that saw income inequality rise in Western countries in the 1980s, happiness inequality has fallen in countries that have experienced income growth (but not in those that did not). Modern growth has reduced the share of both the “very unhappy” and the “perfectly happy”. Lower happiness inequality is found both between and within countries, and between and within individuals. Our cross-country regression results argue that the extension of various public goods helps to explain this greater happiness homogeneity. This new stylised fact arguably comes as a bonus to the Easterlin paradox, offering a somewhat brighter perspective for developing countries. PMID:27616797

Pregnancy presenting as hyperthyroidism with negative urine pregnancy test.

PubMed

Jindal, Rita; Deepak, Desh; Ghosh, Gopal Chandra; Gupta, Mamta

2014-05-20

A 22-year-old lactating mother presented with symptoms of uneasiness, palpitation, tachycardia and exophthalmos. She had an abdominal lump suggestive of 26 weeks uterine size but her urine pregnancy test was negative. Her thyroid profile was suggestive of hyperthyroidism. Gynaecological and ultrasonographic findings revealed a hydatidiform mole. She had a low β-human chorionic gonadotropin level that surprisingly increased after suction and evacuation. The paradoxical findings that appeared as erroneous laboratory results could be explained by the 'high-dose hook effect' after a review of literature. One week after the evacuation, the patient's thyroid profile and symptoms resolved completely without any treatment for hyperthyroidism. 2014 BMJ Publishing Group Ltd.

Black Hole Information Problem and Wave Bursts

NASA Astrophysics Data System (ADS)

Gogberashvili, Merab; Pantskhava, Lasha

2018-06-01

By reexamination of the boundary conditions of wave equation on a black hole horizon it is found not harmonic, but real-valued exponentially time-dependent solutions. This means that quantum particles probably do not cross the Schwarzschild horizon, but are absorbed and some are reflected by it, what potentially can solve the famous black hole information paradox. To study this strong gravitational lensing we are introducing an effective negative cosmological constant between the Schwarzschild and photon spheres. It is shown that the reflected particles can obtain their additional energy in this effective AdS space and could explain properties of some unusually strong signals, like LIGO events, gamma ray and fast radio bursts.

The potential of using quantum theory to build models of cognition.

PubMed

Wang, Zheng; Busemeyer, Jerome R; Atmanspacher, Harald; Pothos, Emmanuel M

2013-10-01

Quantum cognition research applies abstract, mathematical principles of quantum theory to inquiries in cognitive science. It differs fundamentally from alternative speculations about quantum brain processes. This topic presents new developments within this research program. In the introduction to this topic, we try to answer three questions: Why apply quantum concepts to human cognition? How is quantum cognitive modeling different from traditional cognitive modeling? What cognitive processes have been modeled using a quantum account? In addition, a brief introduction to quantum probability theory and a concrete example is provided to illustrate how a quantum cognitive model can be developed to explain paradoxical empirical findings in psychological literature. © 2013 Cognitive Science Society, Inc.

Paradoxical articular manifestations in patients with inflammatory bowel diseases treated with infliximab.

PubMed

Thiebault, Henri; Boyard-Lasselin, Pauline; Guignant, Caroline; Guillaume, Nicolas; Wacrenier, Adrien; Sabbagh, Charles; Rebibo, Lionel; Brazier, Franck; Meynier, Jonathan; Nguyen-Khac, Eric; Dupas, Jean-Louis; Goëb, Vincent; Fumery, Mathurin

2016-08-01

Articular involvement is the most common extraintestinal manifestation associated with inflammatory bowel diseases (IBDs). Manifestations are 'paradoxical' when they occur during treatment, notably with anti-tumor necrosis factor (anti-TNF) drugs, which are expected to prevent or treat them. The aim of this study was to assess the frequency, characteristics, and associated factors of paradoxical articular manifestations in patients with IBD treated with anti-TNF. In this prospective single-center study, an examination by a rheumatologist was systematically offered to all patients with IBD treated with infliximab (IFX) to assess the prevalence of articular manifestations and distinguish between those related to treatment and those associated with intestinal disease. Paradoxical manifestations were defined as the occurrence of articular manifestations (excluding induced lupus and hypersensitivity reactions) during anti-TNF therapy in patients with intestinal remission. Measures of biological inflammatory, immunological markers, HLA-B27 allele, IFX trough levels, and anti-IFX antibody (Ab) were performed for all patients. Between May 2013 and April 2014, 65 patients with Crohn's disease and 15 with patients ulcerative colitis treated with IFX were included. The median duration of anti-TNF therapy was 66 months [quartile (Q)1=23 months-Q3=81 months]. Articular manifestations were observed in 50 (62%) patients treated with IFX. Eleven percent (n=9) were considered to be associated with IBD and 16% (n=13) to be associated with anti-TNF therapy. Among articular manifestations associated with anti-TNF therapy, nine (11%) patients were considered paradoxical, two (2%) as drug-induced lupus, and two (2%) as a hypersensitivity reaction. Among the nine patients with paradoxical manifestations, all had Crohn's disease in clinical remission, three patients presented a spondyloarthropathy, and three developed associated paradoxical psoriasis. No patient discontinued anti-TNF because of the articular manifestations. Methotrexate was effective on articular symptoms in two of the three treated patients with paradoxical manifestations. No clinical or biological factors, including IFX trough levels, were associated with the occurrence of paradoxical manifestations. Paradoxical articular manifestations in IBD patients treated by anti-TNF are common, affecting more than 10% of patients. These events are generally mild and do not need discontinuation of anti-TNF therapy.

Managing frame diversity in environmental participatory processes - Example from the Fogera woreda in Ethiopia.

PubMed

Hassenforder, Emeline; Brugnach, Marcela; Cullen, Beth; Ferrand, Nils; Barreteau, Olivier; Daniell, Katherine Anne; Pittock, Jamie

2016-07-15

Many participatory processes fail to generate social change and collaborative outcomes. This failure can partly be explained by how divergent stakeholders' frames are handled. This paper builds on the framing and participation literature to explain how facilitators can manage frame diversity and foster collaborative outcomes. It suggests two pragmatic steps: identifying frames and managing frames. The two steps are applied to a participatory process for natural resource management in Fogera, Ethiopia. Effectiveness of facilitators' strategies to manage frame diversity in the Fogera case is discussed. Two main elements challenging effectiveness are identified: counter-strategies used by facilitators and most-powerful stakeholders, and the constraining factors knowledge, champions and frame sponsorship. We argue that these elements need to be taken into account by participatory process facilitators when managing frame diversity. Copyright © 2016 Elsevier Ltd. All rights reserved.

Paradox Lost? No, Paradox Found! Reply to Tomasello and Akhtar (2003).

ERIC Educational Resources Information Center

Naigles, Letitia R.

2003-01-01

Asserts that the posited paradox between infancy and toddlerhood language was not eliminated by Tomasello and Akhtar's appeal to infants' robust statistical learning abilities. Maintains that scrutiny of their studies supports the resolution that abstracting linguistic form is easy for infants and that toddlers find it difficult to integrate…

Killing Mosquitoes and Keeping Practice: Teacher Education as Sustaining Paradox

ERIC Educational Resources Information Center

Keiser, David Lee

2013-01-01

The moral and ethical charge of teaching and teacher education includes sustaining equanimity and paradox, and maintaining poise amongst contradicting policies and interests. This paper draws upon the wisdom of the Tao Te Ching to address some paradoxes in education and teacher preparation. Specifically, the article looks at four chapters of the…

The Role of Cognitive Disposition in Re-Examining the Privacy Paradox: A Neuroscience Study

ERIC Educational Resources Information Center

Mohammed, Zareef

2017-01-01

The privacy paradox is a phenomenon whereby individuals continue to disclose their personal information, contrary to their claim of concerns for the privacy of their personal information. This study investigated the privacy paradox to better understand individuals' decisions to disclose or withhold their personal information. The study argued that…

CROWN GALL INCIDENCE: SEEDLING PARADOX WALNUT ROOTSTOCK VERSUS OWN-ROOTED ENGLISH WALNUT TREES

USDA-ARS?s Scientific Manuscript database

Seedling Paradox (Juglans hindsii x J. regia) has been the rootstock of choice for English walnut in California because of its vigor and greater tolerance of wet soil conditions. However, seedling Paradox rootstock is highly susceptible to crown gall, a disease caused by the soil-borne bacterium Agr...

The Power of Why: Engaging the Goal Paradox in Program Evaluation

ERIC Educational Resources Information Center

Friedman, Victor J.; Rothman, Jay; Withers, Bill

2006-01-01

Clearly defined and measurable goals are commonly considered prerequisites for effective evaluation. Goal setting, however, presents a paradox to evaluators because it takes place at the interface of rationality and values. The objective of this article is to demonstrate a method for unlocking this paradox by making goal setting a process of…

What Do Police Academy Instructors and STEM Teachers Have in Common? The "Mission Paradox"

ERIC Educational Resources Information Center

Even Zahav, Anat; Shahar, Sigalit; Hazzan, Orit

2016-01-01

This article presents the "Mission Paradox," shared by two public sector organizations in Israel: the police training system and the post-primary STEM education system. The "Mission Paradox" was identified in data analysis of two doctoral studies, which implemented a qualitative methodology. The study's purpose was to analyze…

Yule-Simpson's Paradox in Research

ERIC Educational Resources Information Center

Goltz, Heather Honore; Smith, Matthew Lee

2010-01-01

Yule (1903) and Simpson (1951) described a statistical paradox that occurs when data is aggregated. In such situations, aggregated data may reveal a trend that directly contrasts those of sub-groups trends. In fact, the aggregate data trends may even be opposite in direction of sub-group trends. To reveal Yule-Simpson's paradox (YSP)-type…

Biochemical pharmacology of paradoxical sleep

PubMed Central

Gaillard, J. -M.

1983-01-01

1 The role of noradrenergic cells in the regulation of paradoxical sleep is still controversial, and experimental data have given rise to contradictory interpretations. 2 Early investigations focused primarily on chemical neurotransmissions. However, the process of information transmission between cells involves many other factors, and the cell surface is an important site for transduction of messages into modifications of the activity of postsynaptic cells. 3 α-adrenoceptors are believed to play an important role in the control of wakefulness and paradoxical sleep. Experimental evidence suggests that physiological modulation of receptor sensitivity, possibly by specific neuro-modulators, may be a key mechanism in synaptic transmission. 4 In the investigation of the mechanisms involved in paradoxical sleep regulation, lesions of the locus coeruleus have given equivocal results. Collateral inhibition, probably mediated by α2-adrenoceptors, appears to be a powerful mechanism. The exact temporal relationship between noradrenergic cell activation and paradoxical sleep production is not established, but 5-HT appears to be involved. Differences between paradoxical sleep and waking may be related to a physiological modulation of α2-adrenoceptor sensitivity. PMID:6140943

Aristotle Meets Zeno: Psychophysiological Evidence

PubMed Central

Papageorgiou, Charalabos; Stachtea, Xanthi; Papageorgiou, Panos; Alexandridis, Antonio T.

2016-01-01

This study, a tribute to Aristotle's 2400 years, used a juxtaposition of valid Aristotelian arguments to the paradoxes formulated by Zeno the Eleatic, in order to investigate the electrophysiological correlates of attentional and /or memory processing effects in the course of deductive reasoning. Participants undertook reasoning tasks based on visually presented arguments which were either (a) valid (Aristotelian) statements or (b) paradoxes. We compared brain activation patterns while participants maintained the premises / conclusions of either the valid statements or the paradoxes in working memory (WM). Event-related brain potentials (ERPs), specifically the P300 component of ERPs, were recorded during the WM phase, during which participants were required to draw a logical conclusion regarding the correctness of the valid syllogisms or the paradoxes. During the processing of paradoxes, results demonstrated a more positive event-related potential deflection (P300) across frontal regions, whereas processing of valid statements was associated with noticeable P300 amplitudes across parieto-occipital regions. These findings suggest that paradoxes mobilize frontal attention mechanisms, while valid deduction promotes parieto-occipital activity associated with attention and/or subsequent memory processing. PMID:28033333

Aristotle Meets Zeno: Psychophysiological Evidence.

PubMed

Papageorgiou, Charalabos; Stachtea, Xanthi; Papageorgiou, Panos; Alexandridis, Antonio T; Tsaltas, Eleftheria; Angelopoulos, Elias

2016-01-01

This study, a tribute to Aristotle's 2400 years, used a juxtaposition of valid Aristotelian arguments to the paradoxes formulated by Zeno the Eleatic, in order to investigate the electrophysiological correlates of attentional and /or memory processing effects in the course of deductive reasoning. Participants undertook reasoning tasks based on visually presented arguments which were either (a) valid (Aristotelian) statements or (b) paradoxes. We compared brain activation patterns while participants maintained the premises / conclusions of either the valid statements or the paradoxes in working memory (WM). Event-related brain potentials (ERPs), specifically the P300 component of ERPs, were recorded during the WM phase, during which participants were required to draw a logical conclusion regarding the correctness of the valid syllogisms or the paradoxes. During the processing of paradoxes, results demonstrated a more positive event-related potential deflection (P300) across frontal regions, whereas processing of valid statements was associated with noticeable P300 amplitudes across parieto-occipital regions. These findings suggest that paradoxes mobilize frontal attention mechanisms, while valid deduction promotes parieto-occipital activity associated with attention and/or subsequent memory processing.

Towards an Einstein-Podolsky-Rosen paradox between two macroscopic atomic ensembles at room temperature

NASA Astrophysics Data System (ADS)

He, Q. Y.; Reid, M. D.

2013-06-01

Experiments have reported the entanglement of two spatially separated macroscopic atomic ensembles at room temperature (Krauter et al 2011 Phys. Rev. Lett. 107 080503; Julsgaard et al 2001 Nature 413 400). We show how an Einstein-Podolsky-Rosen (EPR) paradox is realizable with this experiment. Our proposed test involves violation of an inferred Heisenberg uncertainty principle, which is a sufficient condition for an EPR paradox. This is a stronger test of nonlocality than entanglement. Our proposal would enable the first definitive confirmation of quantum EPR paradox correlations between two macroscopic objects at room temperature. This is a necessary intermediate step towards a nonlocal experiment with causal measurement separations. As well as having fundamental significance, the realization of an atomic EPR paradox could provide a resource for novel applications in quantum technology.

Paradoxical self-esteem and selectivity in the processing of social information.

PubMed

Tafarodi, R W

1998-05-01

Paradoxical self-esteem is defined as contrasting levels of self-liking and self-competence. Consideration of the social and motivational implications of this uncommon form of self-esteem suggests that heightened selectivity in the processing of social information may be behind its persistence. Two experiments were conducted to confirm the prediction of heightened selectivity in paradoxicals. As expected, those paradoxically low in self-liking were more negatively biased in their memory for personality feedback (Study 1) and interpretation of valuatively ambiguous phrases (Study 2) than were their counterparts who shared the same low self-liking but were also low in self-competence. Symmetrical with this result, those paradoxically high in self-liking exhibited a heightened positive bias relative to those who were high in both self-liking and self-competence. The findings are discussed in relation to attitudes and motivation.

A simple explanation of the classic hydrostatic paradox

NASA Astrophysics Data System (ADS)

Kontomaris, Stylianos-Vasileios; Malamou, Anna

2016-07-01

An interesting problem in fluid mechanics, with significant educational importance, is the classic hydrostatic paradox. The hydrostatic paradox states the fact that in different shaped containers, with the same base area, which are filled with a liquid of the same height, the applied force by the liquid on the base of each container is exactly the same. However, if the shape of the container is different, the amount of the liquid (and as a consequence the weight) can greatly vary. In this paper, a simple explanation of the hydrostatic paradox, specifically designed and implemented for educational purposes regarding secondary education, is provided.

Connecting Diversity Efforts in the Workplace with Business Mission, Goals, and Objectives.

ERIC Educational Resources Information Center

Johnson, Sandra J.

1994-01-01

Discusses the management and evaluation of diversity in the workforce and emphasizes the need to link diversity issues with organizational goals and performance needs. Differences between a "quick fix" and systematic action are examined; distinctions between a program and a process are explained; and measuring results of diversity…

Diversity in Teacher Education: New Expectations.

ERIC Educational Resources Information Center

Dilworth, Mary E., Ed.

The increasing racial and ethnic diversity of classrooms in the United States presents a significant challenge to the next generation of teachers and to those responsible for their training. This book explains the steps teacher educators and policymakers must take in order to prepare a teaching force that is both culturally diverse and culturally…

Relationships between Adaptive Behaviours, Personal Factors, and Participation of Young Children.

PubMed

Killeen, Hazel; Shiel, Agnes; Law, Mary; O'Donovan, Donough J; Segurado, Ricardo; Anaby, Dana

2017-12-19

To examine the extent to which personal factors (age, socioeconomic grouping, and preterm birth) and adaptive behaviour explain the participation patterns of young children. 65 Children 2-5 years old with and without a history of preterm birth and no physical or intellectual disability were selected by convenience sampling from Galway University Hospital, Ireland. Interviews with parents were conducted using the Adaptive Behaviour Assessment System, Second Edition (ABAS-II) and the Assessment of Preschool Children's Participation (APCP). Linear regression models were used to identify associations between the ABAS-II scores, personal factors, and APCP scores for intensity and diversity of participation. Adaptive behaviour explained 21% of variance in intensity of play, 18% in intensity of Skill Development, 7% in intensity of Active Physical Recreation, and 6% in intensity of Social Activities controlling for age, preterm birth, and socioeconomic grouping. Age explained between 1% and 11% of variance in intensity of participation scores. Adapted behaviour (13%), Age (17%), and socioeconomic grouping (5%) explained a significant percentage of variance in diversity of participation controlling for the other variables.  Adaptive behaviour had a unique contribution to children's intensity and diversity of participation, suggesting its importance.

Environment and host as large-scale controls of ectomycorrhizal fungi.

PubMed

van der Linde, Sietse; Suz, Laura M; Orme, C David L; Cox, Filipa; Andreae, Henning; Asi, Endla; Atkinson, Bonnie; Benham, Sue; Carroll, Christopher; Cools, Nathalie; De Vos, Bruno; Dietrich, Hans-Peter; Eichhorn, Johannes; Gehrmann, Joachim; Grebenc, Tine; Gweon, Hyun S; Hansen, Karin; Jacob, Frank; Kristöfel, Ferdinand; Lech, Paweł; Manninger, Miklós; Martin, Jan; Meesenburg, Henning; Merilä, Päivi; Nicolas, Manuel; Pavlenda, Pavel; Rautio, Pasi; Schaub, Marcus; Schröck, Hans-Werner; Seidling, Walter; Šrámek, Vít; Thimonier, Anne; Thomsen, Iben Margrete; Titeux, Hugues; Vanguelova, Elena; Verstraeten, Arne; Vesterdal, Lars; Waldner, Peter; Wijk, Sture; Zhang, Yuxin; Žlindra, Daniel; Bidartondo, Martin I

2018-06-06

Explaining the large-scale diversity of soil organisms that drive biogeochemical processes-and their responses to environmental change-is critical. However, identifying consistent drivers of belowground diversity and abundance for some soil organisms at large spatial scales remains problematic. Here we investigate a major guild, the ectomycorrhizal fungi, across European forests at a spatial scale and resolution that is-to our knowledge-unprecedented, to explore key biotic and abiotic predictors of ectomycorrhizal diversity and to identify dominant responses and thresholds for change across complex environmental gradients. We show the effect of 38 host, environment, climate and geographical variables on ectomycorrhizal diversity, and define thresholds of community change for key variables. We quantify host specificity and reveal plasticity in functional traits involved in soil foraging across gradients. We conclude that environmental and host factors explain most of the variation in ectomycorrhizal diversity, that the environmental thresholds used as major ecosystem assessment tools need adjustment and that the importance of belowground specificity and plasticity has previously been underappreciated.

A test of multiple hypotheses for the species richness gradient of South American owls.

PubMed

Diniz-Filho, José Alexandre Felizola; Rangel, Thiago F L V B; Hawkins, Bradford A

2004-08-01

Many mechanisms have been proposed to explain broad scale spatial patterns in species richness. In this paper, we evaluate five explanations for geographic gradients in species richness, using South American owls as a model. We compared the explanatory power of contemporary climate, landcover diversity, spatial climatic heterogeneity, evolutionary history, and area. An important aspect of our analyses is that very different hypotheses, such as history and area, can be quantified at the same observation scale and, consequently can be incorporated into a single analytical framework. Both area effects and owl phylogenetic history were poorly associated with richness, whereas contemporary climate, climatic heterogeneity at the mesoscale and landcover diversity explained ca. 53% of the variation in species richness. We conclude that both climate and environmental heterogeneity should be retained as plausible explanations for the diversity gradient. Turnover rates and scaling effects, on the other hand, although perhaps useful for detecting faunal changes and beta diversity at local and regional scales, are not strong explanations for the owl diversity gradient.

Habitat connectivity and in-stream vegetation control temporal variability of benthic invertebrate communities.

PubMed

Huttunen, K-L; Mykrä, H; Oksanen, J; Astorga, A; Paavola, R; Muotka, T

2017-05-03

One of the key challenges to understanding patterns of β diversity is to disentangle deterministic patterns from stochastic ones. Stochastic processes may mask the influence of deterministic factors on community dynamics, hindering identification of the mechanisms causing variation in community composition. We studied temporal β diversity (among-year dissimilarity) of macroinvertebrate communities in near-pristine boreal streams across 14 years. To assess whether the observed β diversity deviates from that expected by chance, and to identify processes (deterministic vs. stochastic) through which different explanatory factors affect community variability, we used a null model approach. We observed that at the majority of sites temporal β diversity was low indicating high community stability. When stochastic variation was unaccounted for, connectivity was the only variable explaining temporal β diversity, with weakly connected sites exhibiting higher community variability through time. After accounting for stochastic effects, connectivity lost importance, suggesting that it was related to temporal β diversity via random colonization processes. Instead, β diversity was best explained by in-stream vegetation, community variability decreasing with increasing bryophyte cover. These results highlight the potential of stochastic factors to dampen the influence of deterministic processes, affecting our ability to understand and predict changes in biological communities through time.

Historical factors shaped species diversity and composition of Salix in eastern Asia.

PubMed

Wang, Qinggang; Su, Xiangyan; Shrestha, Nawal; Liu, Yunpeng; Wang, Siyang; Xu, Xiaoting; Wang, Zhiheng

2017-02-08

Ambient energy, niche conservatism, historical climate stability and habitat heterogeneity hypothesis have been proposed to explain the broad-scale species diversity patterns and species compositions, while their relative importance have been controversial. Here, we assessed the relative contributions of contemporary climate, historical climate changes and habitat heterogeneity in shaping Salix species diversity and species composition in whole eastern Asia as well as mountains and lowlands using linear regressions and distance-based redundancy analyses, respectively. Salix diversity was negatively related with mean annual temperature. Habitat heterogeneity was more important than contemporary climate in shaping Salix diversity patterns, and their relative contributions were different in mountains and lowlands. In contrast, the species composition was strongly influenced by contemporary climate and historical climate change than habitat heterogeneity, and their relative contributions were nearly the same both in mountains and lowlands. Our findings supported niche conservatism and habitat heterogeneity hypotheses, but did not support ambient energy and historical climate stability hypotheses. The diversity pattern and species composition of Salix could not be well-explained by any single hypothesis tested, suggesting that other factors such as disturbance history and diversification rate may be also important in shaping the diversity pattern and composition of Salix species.

Historical factors shaped species diversity and composition of Salix in eastern Asia

PubMed Central

Wang, Qinggang; Su, Xiangyan; Shrestha, Nawal; Liu, Yunpeng; Wang, Siyang; Xu, Xiaoting; Wang, Zhiheng

2017-01-01

Ambient energy, niche conservatism, historical climate stability and habitat heterogeneity hypothesis have been proposed to explain the broad-scale species diversity patterns and species compositions, while their relative importance have been controversial. Here, we assessed the relative contributions of contemporary climate, historical climate changes and habitat heterogeneity in shaping Salix species diversity and species composition in whole eastern Asia as well as mountains and lowlands using linear regressions and distance-based redundancy analyses, respectively. Salix diversity was negatively related with mean annual temperature. Habitat heterogeneity was more important than contemporary climate in shaping Salix diversity patterns, and their relative contributions were different in mountains and lowlands. In contrast, the species composition was strongly influenced by contemporary climate and historical climate change than habitat heterogeneity, and their relative contributions were nearly the same both in mountains and lowlands. Our findings supported niche conservatism and habitat heterogeneity hypotheses, but did not support ambient energy and historical climate stability hypotheses. The diversity pattern and species composition of Salix could not be well-explained by any single hypothesis tested, suggesting that other factors such as disturbance history and diversification rate may be also important in shaping the diversity pattern and composition of Salix species. PMID:28176816

Eastward shift and maintenance of Arabian Sea oxygen minimum zone: Understanding the paradox

NASA Astrophysics Data System (ADS)

Acharya, Shiba Shankar; Panigrahi, Mruganka K.

2016-09-01

The dominance of Oxygen Minimum Zone in the eastern part of the Arabian Sea (ASOMZ) instead of the more bio-productive and likely more oxygen consuming western part is the first part of the paradox. The sources of oxygen to the ASOMZ were evaluated through the distributions of different water masses using the extended optimum multiparameter (eOMP) analysis, whereas the sinks of oxygen were evaluated through the organic matter remineralization, using the apparent oxygen utilization (AOU). The contributions of major source waters to the Arabian Sea viz. Indian Deep water (dIDW), Indian Central water (ICW), Persian Gulf Water (PGW) and Red Sea Water (RSW) have been quantified through the eOMP analysis which shows that the PGW and RSW are significant for the eastward shift of ASOMZ instead of voluminous ICW and dIDW. The distribution of Net Primary Production (NPP) and AOU clearly suggest the transport of organic detritus from the highly productive western Arabian Sea to its eastern counterpart which adds to the eastward shifting of ASOMZ. A revised estimate of the seasonal variation of areal extent and volume occupied by ASOMZ through analysis of latest available data reveals a distinct intensification of ASOMZ by 30% and increase in its volume by 5% during the spring-summer transition. However, during this seasonal transition the productivity in the Arabian Sea shows 100% increase in mean NPP. This disparity between ASOMZ and monsoonal variation of productivity is the other part of the paradox, which has been constrained through apparent oxygen utilization, Net Primary Production along with a variation of core depths of source waters. This study reveals a subtle balance between the circulation of marginal oxygen-rich water masses from the western Arabian Sea and organic matter remineralization in the eastern Arabian Sea in different seasons that explains the maintenance of ASOMZ throughout the year.

The intelligence paradox; will ET get the metabolic syndrome? Lessons from and for Earth

PubMed Central

2014-01-01

Mankind is facing an unprecedented health challenge in the current pandemic of obesity and diabetes. We propose that this is the inevitable (and predictable) consequence of the evolution of intelligence, which itself could be an expression of life being an information system driven by entropy. Because of its ability to make life more adaptable and robust, intelligence evolved as an efficient adaptive response to the stresses arising from an ever-changing environment. These adaptive responses are encapsulated by the epiphenomena of “hormesis”, a phenomenon we believe to be central to the evolution of intelligence and essential for the maintenance of optimal physiological function and health. Thus, as intelligence evolved, it would eventually reach a cognitive level with the ability to control its environment through technology and have the ability remove all stressors. In effect, it would act to remove the very hormetic factors that had driven its evolution. Mankind may have reached this point, creating an environmental utopia that has reduced the very stimuli necessary for optimal health and the evolution of intelligence – “the intelligence paradox”. One of the hallmarks of this paradox is of course the rising incidence in obesity, diabetes and the metabolic syndrome. This leads to the conclusion that wherever life evolves, here on earth or in another part of the galaxy, the “intelligence paradox” would be the inevitable side-effect of the evolution of intelligence. ET may not need to just “phone home” but may also need to “phone the local gym”. This suggests another possible reason to explain Fermi’s paradox; Enrico Fermi, the famous physicist, suggested in the 1950s that if extra-terrestrial intelligence was so prevalent, which was a common belief at the time, then where was it? Our suggestion is that if advanced life has got going elsewhere in our galaxy, it can’t afford to explore the galaxy because it has to pay its healthcare costs. PMID:25089149

Successful ageing: A study of the literature using citation network analysis.

PubMed

Kusumastuti, Sasmita; Derks, Marloes G M; Tellier, Siri; Di Nucci, Ezio; Lund, Rikke; Mortensen, Erik Lykke; Westendorp, Rudi G J

2016-11-01

Ageing is accompanied by an increased risk of disease and a loss of functioning on several bodily and mental domains and some argue that maintaining health and functioning is essential for a successful old age. Paradoxically, studies have shown that overall wellbeing follows a curvilinear pattern with the lowest point at middle age but increases thereafter up to very old age. To shed further light on this paradox, we reviewed the existing literature on how scholars define successful ageing and how they weigh the contribution of health and functioning to define success. We performed a novel, hypothesis-free and quantitative analysis of citation networks exploring the literature on successful ageing that exists in the Web of Science Core Collection Database using the CitNetExplorer software. Outcomes were visualized using timeline-based citation patterns. The clusters and sub-clusters of citation networks identified were starting points for in-depth qualitative analysis. Within the literature from 1902 through 2015, two distinct citation networks were identified. The first cluster had 1146 publications and 3946 citation links. It focused on successful ageing from the perspective of older persons themselves. Analysis of the various sub-clusters emphasized the importance of coping strategies, psycho-social engagement, and cultural differences. The second cluster had 609 publications and 1682 citation links and viewed successful ageing based on the objective measurements as determined by researchers. Subsequent sub-clustering analysis pointed to different domains of functioning and various ways of assessment. In the current literature two mutually exclusive concepts of successful ageing are circulating that depend on whether the individual himself or an outsider judges the situation. These different points of view help to explain the disability paradox, as successful ageing lies in the eyes of the beholder. Copyright © 2016 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Introducing the Levinthal's Protein Folding Paradox and Its Solution

ERIC Educational Resources Information Center

Martínez, Leandro

2014-01-01

The protein folding (Levinthal's) paradox states that it would not be possible in a physically meaningful time to a protein to reach the native (functional) conformation by a random search of the enormously large number of possible structures. This paradox has been solved: it was shown that small biases toward the native conformation result…

Bolzano's Approach to the Paradoxes of Infinity: Implications for Teaching

ERIC Educational Resources Information Center

Waldegg, Guillermina

2005-01-01

In this paper we analyze excerpts of "Paradoxes of the Infinite", the posthumous work of Bernard Bolzano (1781-1848), in order to show that Georg Cantor's (1845-1918) approach to the problem of defining actual mathematical infinity is not the most natural. In fact, Bolzano's approach to the paradoxes of infinity is more intuitive, while remaining…

The Use of Paradoxical Intention in the Treatment of Panic Attacks.

ERIC Educational Resources Information Center

Dattilio, Frank M.

1987-01-01

Discusses the counseling use of paradoxical intention, in which clients are told to perform responses that seem incompatible with the goal for which they are seeking help. The use of paradoxical intention in the treatment of panic attacks is described and a case example is included. The nature and implementation of the technique are discussed.…

Ethics and Social Justice within the New DEEL: Addressing the Paradox of Control/Democracy

ERIC Educational Resources Information Center

Shapiro, Joan Poliner

2006-01-01

This paper addresses the ethical and social justice implications of an educational movement called, The New DEEL (Democratic Ethical Educational Leadership). In particular, this paper emphasizes the ethical underpinnings of this movement by focusing on the paradox in the form of the dyad of control/democracy. This important paradox is developed…

(Information) Paradox Regained? A Brief Comment on Maudlin on Black Hole Information Loss

NASA Astrophysics Data System (ADS)

Manchak, J. B.; Weatherall, James Owen

2018-04-01

We discuss some recent work by Tim Maudlin concerning Black Hole Information Loss. We argue, contra Maudlin, that there is a paradox, in the straightforward sense that there are propositions that appear true, but which are incompatible with one another. We discuss the significance of the paradox and Maudlin's response to it.

Two Paradoxes of the "Seller's Market" of Chinese Higher Education

ERIC Educational Resources Information Center

Huang, J.

2005-01-01

In recent years, two "paradoxes" have emerged in the "seller's market" of Chinese higher education. One is a strong demand for buying educational services and a weak demand for consumption; a second is the coexistence of an entry to the seller's market and an exit point from the buyer's market. These two "paradoxes"…

Shade Tolerance of Festuca paradoxa Desv., a Cool-Season Grass Native to North America

Treesearch

Nadia Navarrete-Tindall; Larry Mechlin; J. W. Van Sambeek

2003-01-01

Paradox grass (Festuca paradoxa Desv.) is a native cool-season grass found in prairies and forest openings. Paradox grass has not been included in tree plantings. To determine paradox grass adaptation to shaded environmmts, we established a pot experiment in the shade laboratory at the University of Missouri Horticulture and Agroforestry Research...

Facing Paradox Everyday: A Heideggerian Approach to the Ethics of Teaching

ERIC Educational Resources Information Center

d'Agnese, Vasco

2016-01-01

In this paper, I wish to offer insight into the role of paradox in teaching. I will do so by analyzing teachers' everyday work, taking a qualitative approach and constructing a small-scale empirical study. Philosophically, my attempt is framed by Heidegger's thought. Drawing from research data, I argue the following: (a) paradoxes and dilemmas are…

A Simple Explanation of the Classic Hydrostatic Paradox

ERIC Educational Resources Information Center

Kontomaris, Stylianos-Vasileios; Malamou, Anna

2016-01-01

An interesting problem in fluid mechanics, with significant educational importance, is the classic hydrostatic paradox. The hydrostatic paradox states the fact that in different shaped containers, with the same base area, which are filled with a liquid of the same height, the applied force by the liquid on the base of each container is exactly the…

Positive diversity–invasibility relationship in species-rich semi-natural grassland at the neighbourhood scale

PubMed Central

Zeiter, Michaela; Stampfli, Andreas

2012-01-01

Background and Aims Attempts to answer the old question of whether high diversity causes high invasion resistance have resulted in an invasion paradox: while large-scale studies often find a positive relationship between diversity and invasibility, small-scale experimental studies often find a negative relationship. Many of the small-scale studies are conducted in artificial communities of even-aged plants. Species in natural communities, however, do not represent one simultaneous cohort and occur at various levels of spatial aggregation at different scales. This study used natural patterns of diversity to assess the relationship between diversity and invasibility within a uniformly managed, semi-natural community. Methods In species-rich grassland, one seed of each of ten species was added to each of 50 contiguous 16 cm2 quadrats within seven plots (8 × 100 cm). The emergence of these species was recorded in seven control plots, and establishment success was measured in relation to the species diversity of the resident vegetation at two spatial scales, quadrat (64 cm2) within plots (800 cm2) and between plots within the site (approx. 400 m2) over 46 months. Key Results Invader success was positively related to resident species diversity and richness over a range of 28–37 species per plot. This relationship emerged 7 months after seed addition and remained over time despite continuous mortality of invaders. Conclusions Biotic resistance to plant invasion may play only a sub-ordinate role in species-rich, semi-natural grassland. As possible alternative explanations for the positive diversity–invasibility relationship are not clear, it is recommended that future studies elaborate fine-scale environmental heterogeneity in resource supplies or potential resource flows from resident species to seedlings by means of soil biological networks established by arbuscular mycorrhizal fungi. PMID:22956533

General Relationships between Abiotic Soil Properties and Soil Biota across Spatial Scales and Different Land-Use Types

PubMed Central

Birkhofer, Klaus; Schöning, Ingo; Alt, Fabian; Herold, Nadine; Klarner, Bernhard; Maraun, Mark; Marhan, Sven; Oelmann, Yvonne; Wubet, Tesfaye; Yurkov, Andrey; Begerow, Dominik; Berner, Doreen; Buscot, François; Daniel, Rolf; Diekötter, Tim; Ehnes, Roswitha B.; Erdmann, Georgia; Fischer, Christiane; Foesel, Bärbel; Groh, Janine; Gutknecht, Jessica; Kandeler, Ellen; Lang, Christa; Lohaus, Gertrud; Meyer, Annabel; Nacke, Heiko; Näther, Astrid; Overmann, Jörg; Polle, Andrea; Pollierer, Melanie M.; Scheu, Stefan; Schloter, Michael; Schulze, Ernst-Detlef; Schulze, Waltraud; Weinert, Jan; Weisser, Wolfgang W.; Wolters, Volkmar; Schrumpf, Marion

2012-01-01

Very few principles have been unraveled that explain the relationship between soil properties and soil biota across large spatial scales and different land-use types. Here, we seek these general relationships using data from 52 differently managed grassland and forest soils in three study regions spanning a latitudinal gradient in Germany. We hypothesize that, after extraction of variation that is explained by location and land-use type, soil properties still explain significant proportions of variation in the abundance and diversity of soil biota. If the relationships between predictors and soil organisms were analyzed individually for each predictor group, soil properties explained the highest amount of variation in soil biota abundance and diversity, followed by land-use type and sampling location. After extraction of variation that originated from location or land-use, abiotic soil properties explained significant amounts of variation in fungal, meso- and macrofauna, but not in yeast or bacterial biomass or diversity. Nitrate or nitrogen concentration and fungal biomass were positively related, but nitrate concentration was negatively related to the abundances of Collembola and mites and to the myriapod species richness across a range of forest and grassland soils. The species richness of earthworms was positively correlated with clay content of soils independent of sample location and land-use type. Our study indicates that after accounting for heterogeneity resulting from large scale differences among sampling locations and land-use types, soil properties still explain significant proportions of variation in fungal and soil fauna abundance or diversity. However, soil biota was also related to processes that act at larger spatial scales and bacteria or soil yeasts only showed weak relationships to soil properties. We therefore argue that more general relationships between soil properties and soil biota can only be derived from future studies that consider larger spatial scales and different land-use types. PMID:22937029

Immune reconstitution inflammatory syndrome associated with toxoplasmic encephalitis in HIV-infected patients.

PubMed

van Bilsen, Ward P H; van den Berg, Charlotte H S B; Rijnders, Bart J A; Brinkman, Kees; Mulder, Jan W; Gelinck, Luc B S; Hoepelman, Andy I M; Wit, Ferdinand W N M; van de Beek, Diederik; Prins, Jan M

2017-06-19

To investigate the incidence and risk factors of immune reconstitution inflammatory syndrome (IRIS) associated with toxoplasmic encephalitis (TE) in patients starting combination antiretroviral therapy (cART). A historical multicenter cohort study. We included all HIV-infected patients diagnosed with toxoplasmic encephalitis in six Dutch hospitals between 1996 and 2016. Diagnosis of TE-IRIS was made using predefined IRIS criteria. We distinguished paradoxical TE-IRIS (worsening of underlying treated infection) from unmasking TE-IRIS (unmasking of subclinical infection after start of cART). We compared CD4 cell count, plasma viral load and timing of cART initiation between patients with and without paradoxical TE-IRIS. A total of 211 toxoplasmic encephalitis cases were included. Among 143 cases at risk for paradoxical TE-IRIS, we identified five cases of paradoxical TE-IRIS (3.5%). In six other cases, we could not differentiate paradoxical TE-IRIS from recurrence of disease due to inadequate secondary Toxoplasma prophylaxis. There was no difference in time between start of toxoplasmic encephalitis treatment and cART initiation for patients who did or did not develop paradoxical TE-IRIS (P = 0.50). Within the group of 2228 patients who started cART while having a CD4 cell count below 200 × 10 cells/l and receiving adequate primary prophylaxis, we identified eight cases of unmasking TE-IRIS (0.36%). Unmasking TE-IRIS could not be differentiated from a newly occurring toxoplasmic encephalitis in six other patients, as they were not receiving adequate primary prophylaxis against Toxoplasma. Unmasking TE-IRIS was rare in this cohort, whereas paradoxical TE-IRIS did occur more often. We found no relationship between the timing of cART initiation and the occurrence of paradoxical TE-IRIS.