WorldWideScience

Sample records for underlying paradox formation

  1. Underlying Paradox in the European Union's Multilingualism Policies

    Science.gov (United States)

    Johnson, Fern L.

    2013-01-01

    The European Union (EU) has developed comprehensive policies in recent years to promote multilingualism. In this article, major EU policy statements on multilingualism are analyzed to demonstrate how their underlying language ideology produces paradox by both encouraging multilingualism and regulating its definition within the EU. The first…

  2. Paradox

    OpenAIRE

    Thomson, Amanda

    2015-01-01

    A creative non-fiction piece and photo-essay in a magazine, which was the outcome from Paradox: The Magazine Lab. This was a two day residential workshop for artists, writers and activists at Cove Park, Argyll, organised by Pallabs (www.pallabs.org) with the objective to create a magazine in a weekend.

  3. Professional paradox: identity formation in qualified doctors pursuing further training.

    Science.gov (United States)

    Chan, Mercedes; Pratt, Dan; Poole, Gary; Sidhu, Ravi

    2018-03-01

    Many newly qualified specialists and subspecialists pursue additional training. Although their motivations are many, the pursuit of further training as an alternative to unemployment is an emerging trend. Paradoxically, doctors continue as trainees with a consultant's credentials, and without the guarantee of eventual employment. This study explores seven doctors' experiences, the effects of further training on their professional identity formation (PIF), and how these effects are reconciled on a personal and professional level. This phenomenological study involved interviews with seven qualified Canadian specialists (three were female) who pursued additional training in response to a lack of available positions in their respective specialties. Template analysis generated theoretical constructs of influences on their PIF, and characteristics of their lived experiences. Four themes shaped PIF: setting and context; language and communication; responsibilities and privileges; and participants' visions of their future selves. Professional identity formation (PIF) continued to develop in further training, but was inconsistently affirmed by participants' communities of practice. Four major themes characterised training experiences: prescription; managing multiple masters; limiting access to others and community ties; and constantly questioning the value of extra training. Qualified doctors traverse professional paradoxes as they seek further education with no guarantee of employment and provide consultant-level care as 'trainees'. An identity dissonance emerges that may continue until a clear identity is prescribed for them. Although disruptive to these doctors' PIF and personal and professional lives, the long-term effects of additional training are unknown. Its utility and influence on securing employment and future job satisfaction are areas for further research. © 2017 John Wiley & Sons Ltd and The Association for the Study of Medical Education.

  4. No climate paradox under the faint early Sun.

    Science.gov (United States)

    Rosing, Minik T; Bird, Dennis K; Sleep, Norman H; Bjerrum, Christian J

    2010-04-01

    Environmental niches in which life first emerged and later evolved on the Earth have undergone dramatic changes in response to evolving tectonic/geochemical cycles and to biologic interventions, as well as increases in the Sun's luminosity of about 25 to 30 per cent over the Earth's history. It has been inferred that the greenhouse effect of atmospheric CO(2) and/or CH(4) compensated for the lower solar luminosity and dictated an Archaean climate in which liquid water was stable in the hydrosphere. Here we demonstrate, however, that the mineralogy of Archaean sediments, particularly the ubiquitous presence of mixed-valence Fe(II-III) oxides (magnetite) in banded iron formations is inconsistent with such high concentrations of greenhouse gases and the metabolic constraints of extant methanogens. Prompted by this, and the absence of geologic evidence for very high greenhouse-gas concentrations, we hypothesize that a lower albedo on the Earth, owing to considerably less continental area and to the lack of biologically induced cloud condensation nuclei, made an important contribution to moderating surface temperature in the Archaean eon. Our model calculations suggest that the lower albedo of the early Earth provided environmental conditions above the freezing point of water, thus alleviating the need for extreme greenhouse-gas concentrations to satisfy the faint early Sun paradox.

  5. Institutional paradoxes of vat under developing economy of transition period

    Directory of Open Access Journals (Sweden)

    Dmitriy G. Bachurin

    2016-01-01

    Full Text Available Objective to determine the characteristics of the destructive impact of VAT taxation on the socioeconomic situation of the Russian Federation. Methods the research is based on the complex economic and legal methodology including the institutional approach with the account of the national socioeconomic and legal realities determining the conditions of functioning of branches and particular enterprises in the Russian economy. Results the conditions and characteristics of the introduction of VAT in the Russian Federation are viewed the reasons are revealed for the formation and development of the problemcausing VAT in the domestic tax system the socioeconomic implications of VAT are analyzed the viability of replacing VAT for a turnover tax is demonstrated. Scientific novelty for the first time the conceptual position is articulated that under the realities of the reformed Russian economy the normativelegal outline of the VAT complements the accumulated destructive potential blocking the way to the industrial growth in the national economy enhances the asymmetry of conditions of different forms of ownership while the actual conditions of the transition period in Russia do not correspond to the main idea and purpose of VAT as an institution aimed at the efficient relocation of a significant part of the newly created value added to the social sectors and at the modernizing effect on the productive forces for technological improvement in industry. Practical significance the provisions and conclusions of the article can be used when discussing issues on the need for the VAT reform in the Russian Federation including switching to the turnover tax. nbsp

  6. Neural mechanisms underlying paradoxical performance for monetary incentives are driven by loss aversion.

    Science.gov (United States)

    Chib, Vikram S; De Martino, Benedetto; Shimojo, Shinsuke; O'Doherty, John P

    2012-05-10

    Employers often make payment contingent on performance in order to motivate workers. We used fMRI with a novel incentivized skill task to examine the neural processes underlying behavioral responses to performance-based pay. We found that individuals' performance increased with increasing incentives; however, very high incentive levels led to the paradoxical consequence of worse performance. Between initial incentive presentation and task execution, striatal activity rapidly switched between activation and deactivation in response to increasing incentives. Critically, decrements in performance and striatal deactivations were directly predicted by an independent measure of behavioral loss aversion. These results suggest that incentives associated with successful task performance are initially encoded as a potential gain; however, when actually performing a task, individuals encode the potential loss that would arise from failure. Copyright © 2012 Elsevier Inc. All rights reserved.

  7. [Change in the mental contents in the paradoxical stage and in stage 2 under the effects of a benzodiazepine, flunitrazepam].

    Science.gov (United States)

    Gaillard, J M; Phelippeau, M

    1977-01-01

    In some insomniacs under flunitrazepam treatment is noted on one hand a global increase of dream memories, and on the other hand an increase of dreams with unpleasant or anxious contents. The present investigation is intended first to test the hypothesis of a possible increase of mental contents in sleep outside the paradoxical phases, to account for the increase of dream memories without concomitant increase of paradoxical stage. Second it intends to investigate if the increase of unpleasant dreams may be found in the normal subject in laboratory.

  8. Proximity, network formation and inventive performance: in search of the proximity paradox

    OpenAIRE

    Cassi, Lorenzo; Plunket, Anne

    2013-01-01

    This paper investigates how network relations, proximity and their interplay affect collaboration and their inventive performance. Using patent citations as a proxy for patent quality, we investigate how the network and proximity characteristics of co-inventors enable them to access different sources of knowledge, in different geographical and organizational contexts, and finally affect the quality of inventive collaboration. Our findings enable to address the proximity paradox, which states ...

  9. A blessing I can't afford: factors underlying the paradox of happiness about unintended pregnancy.

    Science.gov (United States)

    Aiken, Abigail R A; Dillaway, Chloe; Mevs-Korff, Natasha

    2015-05-01

    An unresolved paradox in the measurement and interpretation of unintended pregnancy is that women frequently report feeling happy about pregnancies they also classify as unintended (i.e. they have incongruent intentions and feelings). This study explores the underlying reasons why women profess such happiness and how these relate to their motivations to avoid pregnancy. Between September 2013 and February 2014, semi-structured in-depth interviews were conducted with 27 women (8 white, 19 Latina) selected from a longitudinal study measuring prospective pregnancy intentions and feelings among 403 women in Austin, Texas. Women were selected for interview on the basis of wanting no more children and consistently professing either happiness (n = 17) or unhappiness (n = 10) at the prospect of pregnancy. Interviews were coded and analyzed following the principles of grounded theory. We found that it is possible for women to express happiness at the idea of pregnancy while simultaneously earnestly trying to prevent conception. Happiness at the idea of an unintended pregnancy was explained as the result of deep and heartfelt feelings about children taking precedence over practical considerations, the perception that the psychosocial stress resulting from another child would be low, and the ability to rationalize an unintended pregnancy as the result of fate or God's plan. The major exception to the sincerity of professed happiness was that conveyed as a result of social pressure despite truly negative feelings, predominantly expressed by foreign-born Latina women. Overall, equating incongruence with ambivalence about avoiding conception may undermine the sincerity of women's intentions and their desires for highly-effective contraception. At the same time, unintended pregnancies that are greeted with happiness may have different implications for maternal and child health outcomes compared to pregnancies that are greeted with unhappiness. Identifying which unintended

  10. The paradox of high shear granulation : the formation of non-homogeneous granules

    NARCIS (Netherlands)

    Dries, Kaspar van den

    2004-01-01

    Wet granulation is a process used for the particle size enlargement of primary powders. The mixing of a liquid with the powder glues the primary particles together, which results in the formation of the granules. The mixing action can be performed in many ways, like tumbling (drum granulation),

  11. The Paradox of Post-Bureaucracy: Trust Formation among State Administration Employees in Finland

    Directory of Open Access Journals (Sweden)

    JAAKKO KOIVUMÄKI

    2012-07-01

    Full Text Available This paper discusses civil servants’ trust in management under conditions of organizational change. The paper draws on asurvey and qualitative interview material collected from five knowledge-intensive public sector organizations in Finland. Theresults indicate that the post-bureaucratic model of organizing work in Finnish state administration may increase insecurityand decrease trust among employees. The paper serves as a reminder that all organizational models have their costs and benefits.Traditional bureaucracy fosters predictability and longevity in employee relations. In this respect, the post-bureaucratic model oforganizing work may not always be as effective in generating trust as traditional bureaucracy is.

  12. The Gothic shale of the Pennsylvanian Paradox Formation Greater Aneth Field (Aneth Unit) Southeastern Utah U.S.A.: Seal for Hydrocarbons and Carbon Dioxide Storage.

    Energy Technology Data Exchange (ETDEWEB)

    Heath, Jason E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Dewers, Thomas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Chidsey, Thomas C. [Utah Geoglogical Survey, Salt Lake City, UT (United States); Carney, Stephanie M. [Utah Geoglogical Survey, Salt Lake City, UT (United States); Bereskin, S. R. [Bereskin and Associates, Salt Lake City (United States)

    2017-05-01

    Greater Aneth oil field, Utah’s largest oil producer, was discovered in 1956 and has produced over 483 million barrels of oil. Located in the Paradox Basin of southeastern Utah, Greater Aneth is a stratigraphic trap producing from the Pennsylvanian (Desmoinesian) Paradox Formation. Because Greater Aneth is a mature, major oil field in the western U.S., and has a large carbonate reservoir, it was selected to demonstrate combined enhanced oil recovery and carbon dioxide storage. The Aneth Unit in the northwestern part of the field has produced over 160 million barrels of the estimated 386 million barrels of original oil in place—a 42% recovery rate. The large amount of remaining oil made the Aneth Unit ideal to enhance oil recovery by carbon dioxide flooding and demonstrate carbon dioxide storage capacity.

  13. What Paradox?

    DEFF Research Database (Denmark)

    Holt, Robin; Zundel, Mike

    2017-01-01

    This chapter investigates the relationship between paradox and the logical typing of classes and members. Class-based thinking affords efficiency in communication and the progressive, additive development of knowledge, but also creates fissures, shortcuts, truncations, and delimitations that gene...

  14. Paradox phenomena of proton exchange membrane fuel cells operating under dead-end anode mode

    Science.gov (United States)

    Jiang, Dong; Zeng, Rong; Wang, Shumao; Jiang, Lijun; Varcoe, John R.

    2014-11-01

    By using two spatially separated reference electrodes in a single cell proton-exchange membrane fuel cell (PEMFC), the individual potentials of the anode and cathode are recorded under realistic operating conditions. The PEMFC is operated under dead-end anode (DEA) mode, without any humidification, to mitigate water accumulation at the anode. Although N2 crossover from cathode to anode may play an important role in PEMFCs operating under DEA mode, our results unexpectedly show that the over-potentials of both the anode and cathode concomitantly increased or decreased at the same time. The increases of over-potentials correlate to the increase of the high frequency resistance of the cell (Rhf) imply that the water content in the membrane electrode assemblies is critical. However, the subsequent H2 depletion tests suggest that water may accumulate at the interface between the surface of the catalyst and the ultrathin perfluorosulfonic acid (PFSA) ionomer film and this contradicts the above (the increase in Rhf implies the drying out of the MEAs). This study highlights the need for further research into understanding the water transport properties of the ultrathin PFSA ionomer film (<60 nm): it is clear that these exhibit completely different properties to that of bulk proton-exchange membranes (PEM).

  15. The Paradox of Analogy

    Directory of Open Access Journals (Sweden)

    David Botting

    2012-03-01

    Full Text Available I will show that there is a type of analogical reasoning that instantiates a pattern of reasoning in confirmation theory that is considered at best paradoxical and at worst fatal to the entire syntactical approach to confirmation and explanation. However, I hope to elaborate conditions under which this is a sound (although not necessarily strong method of reasoning.

  16. More than just one Methane Paradox? - Methane Production in Oxic Waters and Aerobic Methane Oxidation under Oxygen-Depleted Conditions

    Science.gov (United States)

    Lehmann, M. F.; Niemann, H.; Bartosiewicz, M.; Blees, J.; Steinle, L.; Su, G.; Zopfi, J.

    2016-12-01

    The standing paradigm is that methane (CH4) production through methanogenesis occurs exclusively under anoxic conditions and that at least in freshwater environments most of the biogenic CH4 is oxidized by aerobic methanotrophic bacteria (MOB) under oxic conditions. However, subsurface CH4 accumulation in oxic waters, a phenomenon referred to as the "CH4 paradox", has been observed both in the ocean and in lakes, and suggests in-situ CH4 production or a remarkable tolerance of at least some methanogens to O2. Analogously, MOB seem to thrive also under micro-oxic conditions, i.e., they may be responsible for significant CH4 turnover at extremely low O2 concentrations. O2 availability particularly within the sub-micromolar range is likely one of the key factors controlling the balance between CH4 production and consumption in redox-transition zones of aquatic environments, yet threshold O2 concentrations are poorly constrained. Here we provide multiple lines of evidence for apparent "methanogenesis" in well-oxygenated waters and discuss the potential mechanisms that lead to CH4 accumulation in the oxic epilimnia of two south-alpine lakes. On the other end, we present data from a deep meromictic lake, which indicate aerobic CH4 oxidation (MOx) at O2 concentrations below the detection limit of common O2 sensors. A strong MOx potential throughout the anoxic hyplimnion of the studied lake implies that the MOB community is able to survive prolonged periods of O2 starvation and is capable to rapidly resume microaerobic MOx upon introduction of low levels of O2. This conclusion is qualitatively consistent with field data from a coastal shelf environment in the Baltic Sea, where we observed maximum MOx rates during the summer stratification period when O2 concentrations were lowest, implying that in both environments MOx bacteria are adapted to trace levels of O2. Indeed, laboratory experiments at different manipulated O2 concentration levels suggest a nanomolar O2 optimum

  17. Consumer Capital as the Source of Happiness : The Missing Economic Theory Underlying the Income-Happiness Paradox

    NARCIS (Netherlands)

    van Hoorn, André; Sent, Esther-Mirjam

    2016-01-01

    Self-reported happiness does not generally increase with rising income, as established by Richard Easterlin. We argue that the subsequent debate in economics surrounding this income-happiness paradox has paid too little attention to the theoretical foundation for the expected positive relation

  18. KM PARADOX ON CITY MANAGEMENT

    OpenAIRE

    Sebastian-Ion CEPTUREANU; Eduard-Gabriel CEPTUREANU

    2012-01-01

    This paper presents some thoughts about a relative paradox of knowledge management: both a well established area of science and one of the managerial science domains still under scrutiny for several important inconsistencies and misunderstandings.

  19. MATHEMATICS TEACHER: MOVING KNOWLEDGE UNDER FORMATION

    Directory of Open Access Journals (Sweden)

    Roselaine Machado Albernaz

    2010-07-01

    Full Text Available This essay approaches the Mathematics teacher forming process from his/her experiences in the school system and the set of knowledge that hashistorical, philosophical and politically constituted him/her. This set of knowledge not only comprises academic knowledge, but also involves the subjective effects of knowledge it incorporates. Starting from a tale, the character, called ‘researcher-teacher’, conducts the text throughout questions about the forming processes of teachers of such a particular subject as Mathematics. The character seems to have an “interrogative something” which is peculiar to us, teachers, concerned about our disciplinary field. Having the objective of problematize the formation and knowledge of our character, her ways of being, thinking and perceiving, we intend to question, with and through her, the new requirements that have been demanded towards Mathematics teachers and the set of knowledge that constitute her, the way she is, her way of acting and taking  position in the school universe. The proposed essay seeks for an articulation between the fields of Art, Philosophy, Science and Education. It speaks about the intriguing school world, but not least, the ways we think to treat the forming process of Mathematics teachers from a set of logical, subjective and sensitive knowledge.  Key words: Forming process of teachers; mathematics; aesthetic experience; philosophy of difference.

  20. Identity paradoxes

    Directory of Open Access Journals (Sweden)

    Đurić Jelena

    2010-01-01

    Full Text Available The article considers paradoxical nature of identity that emerges from: 1 the very concept of identity whose abstract generality unites various and even opposite features; 2 the processual nature of reality that is easier to express in the poetical metaphors or abstract principles than in unambiguous conceptual networks; 3 the oppose relationship between being and knowledge, mind and matter, subject and object, self and personality. Entangled in the labyrinth which evade efforts to be conceptually defined, the modern thinking of identity moves towards abandoning the idea of “self” on behalf of the “ego” and towards the misapprehension of identity as being identical. This corresponds to the “time of the lost spirit” stretched between the simultaneous need to find an identity and to give it up.

  1. Rootstock influence on iron uptake responses in Citrus leaves and their regulation under the Fe paradox effect

    Directory of Open Access Journals (Sweden)

    Mary-Rus Martinez-Cuenca

    2017-09-01

    Full Text Available Background and aims This work evaluates the regulation of iron uptake responses in Citrus leaves and their involvement in the Fe paradox effect. Methods Experiments were performed in field-grown ‘Navelina’ trees grafted onto two Cleopatra mandarin × Poncirus trifoliata (L. Raf. hybrids with different Fe-chlorosis symptoms: 030146 (non-chlorotic and 030122 (chlorotic. Results Chlorotic leaves were smaller than non-chlorotic ones for both dry weight (DW and area basis, and exhibited marked photosynthetic state affection, but reduced catalase and peroxidase enzymatic activities. Although both samples had a similar total Fe concentration on DW, it was lower in chlorotic leaves when expressed on an area basis. A similar pattern was observed for the total Fe concentration in the apoplast and cell sap and in active Fe (Fe2+ concentration. FRO2 gene expression and ferric chelate reductase (FC-R activity were also lower in chlorotic samples, while HA1 and IRT1 were more induced. Despite similar apoplasmic pH, K+/Ca2+ was higher in chlorotic leaves, and both citrate and malate concentrations in total tissue and apoplast fluid were lower. Conclusion (1 The rootstock influences Fe acquisition system in the leaf; (2 the increased sensitivity to Fe-deficiency as revealed by chlorosis and decreased biomass, was correlated with lower FC-R activity and lower organic acid level in leaf cells, which could cause a decreased Fe mobility and trigger other Fe-stress responses in this organ to enhance acidification and Fe uptake inside cells; and (3 the chlorosis paradox phenomenon in citrus likely occurs as a combination of a marked FC-R activity impairment in the leaf and the strong growth inhibition in this organ.

  2. The metaphysics of D-CTCs: On the underlying assumptions of Deutsch's quantum solution to the paradoxes of time travel

    Science.gov (United States)

    Dunlap, Lucas

    2016-11-01

    I argue that Deutsch's model for the behavior of systems traveling around closed timelike curves (CTCs) relies implicitly on a substantive metaphysical assumption. Deutsch is employing a version of quantum theory with a significantly supplemented ontology of parallel existent worlds, which differ in kind from the many worlds of the Everett interpretation. Standard Everett does not support the existence of multiple identical copies of the world, which the D-CTC model requires. This has been obscured because he often refers to the branching structure of Everett as a "multiverse", and describes quantum interference by reference to parallel interacting definite worlds. But he admits that this is only an approximation to Everett. The D-CTC model, however, relies crucially on the existence of a multiverse of parallel interacting worlds. Since his model is supplemented by structures that go significantly beyond quantum theory, and play an ineliminable role in its predictions and explanations, it does not represent a quantum solution to the paradoxes of time travel.

  3. Formation process of Malaysian modern architecture under influence of nationalism

    OpenAIRE

    宇高, 雄志; 山崎, 大智

    2001-01-01

    This paper examines the Formation Process of Malaysian Modern Architecture under Influence of Nationalism,through the process of independence of Malaysia. The national style as "Malaysian national architecture" which hasengaged on background of political environment under the post colonial situation. Malaysian urban design is alsodetermined under the balance of both of ethnic culture and the national culture. In Malaysia, they decided to choosethe Malay ethnic culture as the national culture....

  4. Formation of neutrophil extracellular traps under low oxygen level

    Directory of Open Access Journals (Sweden)

    Katja Branitzki-Heinemann

    2016-11-01

    Full Text Available Since their discovery, neutrophil extracellular traps (NETs have been characterized as a fundamental host innate immune defense mechanism. Conversely, excessive NET release may have a variety of detrimental consequences for the host. A fine balance between NET formation and elimination is necessary to sustain a protective effect during an infectious challenge. Our own recently published data revealed that stabilization of hypoxia inducible factor 1α (HIF-1α by the iron chelating HIF-1α-agonist desferoxamine or AKB-4924 enhanced the release of phagocyte extracellular traps. Since HIF-1α is a global regulator of the cellular response to low oxygen, we hypothesized that NET formation may be similarly increased under low oxygen conditions. Hypoxia occurs in tissues during infection or inflammation, mostly due to overconsumption of oxygen by pathogens and recruited immune cells. Therefore, experiments were performed to characterize the formation of NETs under hypoxic oxygen conditions compared to normoxia. Human blood-derived neutrophils were isolated and incubated under normoxic (21% oxygen level and compared to hypoxic (1% conditions. Dissolved oxygen levels were monitored in the primary cell culture using a Fibox4-PSt3 measurement system. The formation of NETs was quantified by fluorescence microscopy in response to the known NET-inducer phorbol 12-myristate 13-acetate (PMA or S. aureus wildtype and a nuclease-deficient mutant. In contrast to our hypothesis, spontaneous NET formation of neutrophils incubated under hypoxia was distinctly reduced compared to control neutrophils incubated under normoxia. Furthermore, neutrophils incubated under hypoxia showed significantly reduced formation of NETs in response to PMA. Gene expression analysis revealed that mRNA level of hif-1α as well as hif-1α target genes was not altered. However, in good correlation to the decreased NET formation under hypoxia, the cholesterol content of the neutrophils was

  5. Subcontact Lens Bubble Formation under Low Atmospheric Pressure Conditions.

    Science.gov (United States)

    1986-08-01

    of subcontact lens bubble formation under scleral lenses at altitudes greater than 18,000 ft. Later, after many advances in contact lens fitting and...Reported here are the results of contact lens bubble studies with soft hydrophilic nd rigid gas-permeable lenses . Testing was accomplished in simulated...ccurred at altitudes greater than 20,000 ft. For soft contact lenses , bubble formation was etected in 22 of 92 eyes tested, and occurred at altitudes

  6. Solutions to Organizational Paradox

    DEFF Research Database (Denmark)

    Li, Xin; Worm, Verner; Peihong, Xie

    Organizations face all kinds of paradoxical problems. There exist various solutions to organizational paradoxes. We develop a typology that lists nine possible logical approaches to understanding the relationship between paradoxical opposites, out of which we identify five types of solutions...... to organizational paradox. Four of the five solutions are explicitly associated with four prominent philosophies. We show the relevance of the five solutions to the real world by applying our scheme to understand different solutions to the generic strategy paradox. Finally, we address the question whether...... there is a superior solution and point out the paradox of paradox resolving, namely, paradoxes cannot be resolved once for all and we have to live with them....

  7. Displacement defect formation in complex oxide crystals under irradiation

    NARCIS (Netherlands)

    Ubizskii, SB; Matkovskii, AO; Mironova-Ulmane, N; Skvortsova, [No Value; Suchocki, A; Zhydachevskii, YA; Potera, P

    The work is devoted to an analysis of formation processes of the radiation displacement defects (RDDs) and colour centres (CCs) in complex oxide crystals under irradiation. The calculation results on: the displacement process simulation as well as an analysis of the RDD and CC accumulation kinetics

  8. DBP formation and disinfection under current and future climates - slides

    Science.gov (United States)

    How to predict and monitoring DBP formation under current and future climate is a challenge and important to water plant operations and water supply security. This presentation summarizes a system approach being developed at the EPA Water Resources Adaptation Program (WRAP).

  9. The Paradox of Bone Formation and Bone Loss in Ankylosing Spondylitis: Evolving New Concepts of Bone Formation and Future Trends in Management.

    Science.gov (United States)

    Magrey, Marina N; Khan, Muhammad A

    2017-04-01

    The purpose of the study is to briefly review the molecular mechanisms that leads to structural damage in ankylosing spondylitis (AS), defined as new bone formation resulting in complete or incomplete ankylosis of the spine, and the impact of treatment with biologics to retard this process. The understanding of molecular mechanisms leading to new bone formation in AS has significantly improved but is still incomplete. Availability of biologics has greatly enhanced the treatment of patients with AS, but its impact on slowing the structural damage is still a matter of debate, although a few observational studies have shown that long term use of TNF-α blockers may slow radiographic progression. The availability of newer biologics targeting IL-17/1L23 has shown some promising results in slowing radiographic progression in AS. Although the availability of TNF-inhibitors has greatly enhanced the treatment options for patients with AS, their impact on slowing the structural damage is still not clearly established. However, preliminary results using newer biologics targeting IL-17/1L23 axis are more encouraging but longer follow-up is needed.

  10. The lunar apatite paradox.

    Science.gov (United States)

    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.

  11. Predicting hydrocarbon potential of an earth formation underlying water

    International Nuclear Information System (INIS)

    Damaison, G.J.; Kaplan, I.R.

    1981-01-01

    A method for the on-site collection and examination of small concentrations of a carbonaceous gas, e.g. methane, dissolved in a body of water overlying an earth formation to predict hydrocarbon potential of the earth formation under the body of water, the formation being a source of carbonaceous gas, comprises at a known geographic location sampling the water at a selected flow rate and at a selected depth; continuously vacuum separating the water into liquid and gas phases; separating a selected carbonaceous gas from interfering gas species in the presence of an air carrier vented to atmosphere at a known flow rate; and quantitatively oxidizing the selected gas and then cryogenically trapping an oxidant thereof in the presence of said air carrier to provide for an accurate isotopic examination. (author)

  12. Endocannabinoids Control Platelet Activation and Limit Aggregate Formation under Flow

    Science.gov (United States)

    De Angelis, Valentina; Koekman, Arnold C.; Weeterings, Cees; Roest, Mark; de Groot, Philip G.; Herczenik, Eszter; Maas, Coen

    2014-01-01

    Background The endocannabinoid system has previously been implicated in the regulation of neurons and inflammatory cells. Additionally, it has been reported that endocannabinoid receptors are present on circulating platelets, but there has been conflicting evidence on their contribution to platelet function. Objectives Our aim was to examine the role of endocannabinoids in platelet function in vitro and in vivo. Methods and Results We studied the effects of the well-characterized endogenous endocannabinoid anandamide on platelet aggregation in suspension, α-granule release, calcium mobilization, Syk phosphorylation, as well as platelet spreading and aggregate formation under flow. Anandamide inhibits platelet aggregation and α-granule release by collagen, collagen-derived peptide CRP-XL, ADP, arachidonic acid and thromboxane A2 analogue U46619. However, activation via thrombin receptor PAR-1 stays largely unaffected. Calcium mobilization is significantly impaired when platelets are stimulated with collagen or CRP-XL, but remains normal in the presence of the other agonists. In line with this finding, we found that anandamide prevents collagen-induced Syk phosphorylation. Furthermore, anandamide-treated platelets exhibit reduced spreading on immobilized fibrinogen, have a decreased capacity for binding fibrinogen in solution and show perturbed platelet aggregate formation under flow over collagen. Finally, we investigated the influence of Cannabis sativa consumption by human volunteers on platelet activation. Similar to our in vitro findings with anandamide, ex vivo collagen-induced platelet aggregation and aggregate formation on immobilized collagen under flow were impaired in whole blood of donors that had consumed Cannabis sativa. Conclusions Endocannabinoid receptor agonists reduce platelet activation and aggregate formation both in vitro and ex vivo after Cannabis sativa consumption. Further elucidation of this novel regulatory mechanism for platelet function

  13. Endocannabinoids control platelet activation and limit aggregate formation under flow.

    Directory of Open Access Journals (Sweden)

    Valentina De Angelis

    Full Text Available The endocannabinoid system has previously been implicated in the regulation of neurons and inflammatory cells. Additionally, it has been reported that endocannabinoid receptors are present on circulating platelets, but there has been conflicting evidence on their contribution to platelet function.Our aim was to examine the role of endocannabinoids in platelet function in vitro and in vivo.We studied the effects of the well-characterized endogenous endocannabinoid anandamide on platelet aggregation in suspension, α-granule release, calcium mobilization, Syk phosphorylation, as well as platelet spreading and aggregate formation under flow. Anandamide inhibits platelet aggregation and α-granule release by collagen, collagen-derived peptide CRP-XL, ADP, arachidonic acid and thromboxane A2 analogue U46619. However, activation via thrombin receptor PAR-1 stays largely unaffected. Calcium mobilization is significantly impaired when platelets are stimulated with collagen or CRP-XL, but remains normal in the presence of the other agonists. In line with this finding, we found that anandamide prevents collagen-induced Syk phosphorylation. Furthermore, anandamide-treated platelets exhibit reduced spreading on immobilized fibrinogen, have a decreased capacity for binding fibrinogen in solution and show perturbed platelet aggregate formation under flow over collagen. Finally, we investigated the influence of Cannabis sativa consumption by human volunteers on platelet activation. Similar to our in vitro findings with anandamide, ex vivo collagen-induced platelet aggregation and aggregate formation on immobilized collagen under flow were impaired in whole blood of donors that had consumed Cannabis sativa.Endocannabinoid receptor agonists reduce platelet activation and aggregate formation both in vitro and ex vivo after Cannabis sativa consumption. Further elucidation of this novel regulatory mechanism for platelet function may prove beneficial in the search

  14. Endocannabinoids control platelet activation and limit aggregate formation under flow.

    Science.gov (United States)

    De Angelis, Valentina; Koekman, Arnold C; Weeterings, Cees; Roest, Mark; de Groot, Philip G; Herczenik, Eszter; Maas, Coen

    2014-01-01

    The endocannabinoid system has previously been implicated in the regulation of neurons and inflammatory cells. Additionally, it has been reported that endocannabinoid receptors are present on circulating platelets, but there has been conflicting evidence on their contribution to platelet function. Our aim was to examine the role of endocannabinoids in platelet function in vitro and in vivo. We studied the effects of the well-characterized endogenous endocannabinoid anandamide on platelet aggregation in suspension, α-granule release, calcium mobilization, Syk phosphorylation, as well as platelet spreading and aggregate formation under flow. Anandamide inhibits platelet aggregation and α-granule release by collagen, collagen-derived peptide CRP-XL, ADP, arachidonic acid and thromboxane A2 analogue U46619. However, activation via thrombin receptor PAR-1 stays largely unaffected. Calcium mobilization is significantly impaired when platelets are stimulated with collagen or CRP-XL, but remains normal in the presence of the other agonists. In line with this finding, we found that anandamide prevents collagen-induced Syk phosphorylation. Furthermore, anandamide-treated platelets exhibit reduced spreading on immobilized fibrinogen, have a decreased capacity for binding fibrinogen in solution and show perturbed platelet aggregate formation under flow over collagen. Finally, we investigated the influence of Cannabis sativa consumption by human volunteers on platelet activation. Similar to our in vitro findings with anandamide, ex vivo collagen-induced platelet aggregation and aggregate formation on immobilized collagen under flow were impaired in whole blood of donors that had consumed Cannabis sativa. Endocannabinoid receptor agonists reduce platelet activation and aggregate formation both in vitro and ex vivo after Cannabis sativa consumption. Further elucidation of this novel regulatory mechanism for platelet function may prove beneficial in the search for new

  15. Candida albicans survival and biofilm formation under starvation conditions.

    Science.gov (United States)

    Ning, Y; Hu, X; Ling, J; Du, Y; Liu, J; Liu, H; Peng, Z

    2013-01-01

    To investigate the survival and biofilm formation capacity of Candida albicans in starvation and under anaerobic conditions. Candida albicans growth and survival were monitored in vitro for up to 8 months. Fungal suspensions from late exponential, stationary and starvation phases were incubated on human dentine, polystyrene and glass slides. Scanning electron microscopy (SEM) was used to observe the process of biofilm formation. 2,3-bis(2-Methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxyanilide inner salt (XTT) reduction assay was performed to quantify the biofilm formation capability, and confocal laser scanning microscopy (CLSM) was used to study and make semi-quantitative comparisons of the ultrastructure of biofilms formed on human dentine. 'XTT bioactivity' and 'COMSTAT results' were analysed by two-way analysis of variance (ANOVA) and one-way ANOVA, respectively. Candida albicans survived for over six months. SEM demonstrated that starving C. albicans produced mature biofilms on different substrata. C. albicans of the same growth phase incubated on human dentine displayed significantly higher biofilm formation capability than on polystyrene or glass slides (P roughness coefficient and surface/volume ratio (P < 0.05). Candida albicans cells can survive and form biofilms in anaerobic and nutrient-limited conditions and may pose a treatment challenge. © 2012 International Endodontic Journal.

  16. Mathematical fallacies and paradoxes

    CERN Document Server

    Bunch, Bryan

    1982-01-01

    Stimulating, thought-provoking analysis of the most interesting intellectual inconsistencies in mathematics, physics, and language, including being led astray by algebra (De Morgan's paradox). 1982 edition.

  17. Methyl Iodide Formation Under Postulated Nuclear Reactor Accident Conditions

    International Nuclear Information System (INIS)

    Kircher, J.F.; Barnes, R.H.

    1968-01-01

    The formation of methyl iodide under conditions of postulated nuclear reactor accidents is discussed. Although thermodynamic calculations indicate the equilibrium methyl iodide concentrations would be quite low, calculations based on a simple kinetic scheme involving reaction between small hydrocarbon species and iodine indicate that concentrations higher than equilibrium can occur during the course of the reaction. Such calculations were performed over a wide range of initial species concentrations and a range of temperatures representative of some reactor accident situations. These calculations suggest that little methyl iodide would be expected within the core volume where temperatures are maximum. As the gas leaves the core volume and expands into the plenum region, it cools and the concentration of methyl iodide increases. At the intermediate temperatures which might characterize this region, the formation of methyl iodide from thermally induced reactions could reach its maximum rate. The gas continues to cool, however, and it is probable that by the time it leaves the plenum region it has cooled to the point where thermally induced reactions may be of little importance. Although the thermally induced reactions will become slower as the gas expands and cools, the radiation-induced reactions will not be slowed to the same extent. The gases leaving the core carry fission products and hence a radiation source is available to initiate reaction by a temperature-independent process. An investigation of the radiation chemical formation and decomposition of methyl iodide in the presence of steam suggests that radiation-induced methyl iodide formation will generally be rapid under the postulated accident situations. Thus, in the plenum region where thermal reactions have become slow, the radiation-induced reaction can still proceed and may well become the dominant factor. The same situation probably pertains as well to the containment region. (author)

  18. Paradoxes in a family business

    Directory of Open Access Journals (Sweden)

    Horia MOAȘA

    2017-07-01

    Full Text Available Attention to the subject of organizational paradoxes has been increasing in the last several years as organizational scholars have extolled the opportunities offered by tensions, contradictions and oppositions in understanding organizations, organizing and the organized. This paper demonstrates the theoretical and empirical value of applying a paradox lens on family businesses that undergo a fundamental process of change by discussing three interrelated paradoxes: the paradox of ownership, the paradox of consultancy and the family business paradox.

  19. Formation of lysinoalanine in egg white under alkali treatment.

    Science.gov (United States)

    Zhao, Yan; Luo, Xuying; Li, Jianke; Xu, Mingsheng; Tu, Yonggang

    2016-03-01

    To investigate the formation mechanism of lysinoalanine (LAL) in eggs during the alkali treatment process, NaOH was used for the direct alkali treatment of egg white, ovalbumin, and amino acids; in addition, the amount of LAL formed during the alkali treatment process was measured. The results showed that the alkali treatment resulted in the formation of LAL in the egg white. The LAL content increased with increasing pH and temperature, with the LAL content first increasing and then leveling off with increasing time. The amount of LAL formed in the ovalbumin under the alkali treatment condition accounted for approximately 50.51% to 58.68% of the amount of LAL formed in the egg white. Thus, the LAL formed in the ovalbumin was the main source for the LAL in the egg white during the alkali treatment process. Under the alkali treatment condition, free L-serine, L-cysteine, and L-cystine reacted with L-lysine to form LAL; therefore, they are the precursor amino acids of LAL formed in eggs during the alkali treatment process. © 2016 Poultry Science Association Inc.

  20. Global Trends: Paradox of Progress

    Science.gov (United States)

    2017-01-01

    human history . Human and Animal Health Under Pressure. Changing environmental conditions and increasing global connectivity will affect...PARADOX OF PROGRESS A pub l ica t ion o f the Nat ional In te l l i gence Counci l GLOBAL TRENDS JANUARY 2017 NIC 2017-001 ISBN 978-0-16-093614...1 The Map of the Future 5 Trends Transforming the Global Landscape 29 Near Future: Tensions Are Rising 45 Three Scenarios for the Distant Future

  1. Paradoxes in probability theory

    CERN Document Server

    Eckhardt, William

    2013-01-01

    Paradoxes provide a vehicle for exposing misinterpretations and misapplications of accepted principles. This book discusses seven paradoxes surrounding probability theory.  Some remain the focus of controversy; others have allegedly been solved, however the accepted solutions are demonstrably incorrect. Each paradox is shown to rest on one or more fallacies.  Instead of the esoteric, idiosyncratic, and untested methods that have been brought to bear on these problems, the book invokes uncontroversial probability principles, acceptable both to frequentists and subjectivists. The philosophical disputation inspired by these paradoxes is shown to be misguided and unnecessary; for instance, startling claims concerning human destiny and the nature of reality are directly related to fallacious reasoning in a betting paradox, and a problem analyzed in philosophy journals is resolved by means of a computer program.

  2. The first stars: formation under cosmic ray feedback

    Science.gov (United States)

    Hummel, Jacob A.; Stacy, Athena; Bromm, Volker

    2016-08-01

    We explore the impact of a cosmic ray (CR) background generated by supernova explosions from the first stars on star-forming metal-free gas in a minihalo at z ˜ 25. Starting from cosmological initial conditions, we use the smoothed particle hydrodynamics code GADGET-2 to follow gas collapsing under the influence of a CR background up to densities of n = 1012 cm-3, at which point we form sink particles. Using a suite of simulations with two sets of initial conditions and employing a range of CR background models, we follow each simulation for 5000 yr after the first sink forms. CRs both heat and ionize the gas, boosting H2 formation. Additional H2 enhances the cooling efficiency of the gas, allowing it to fulfil the Rees-Ostriker criterion sooner and expediting the collapse, such that each simulation reaches high densities at a different epoch. As it exits the loitering phase, the thermodynamic path of the collapsing gas converges to that seen in the absence of any CR background. By the time the gas approaches sink formation densities, the thermodynamic state of the gas is thus remarkably similar across all simulations. This leads to a robust characteristic mass that is largely independent of the CR background, of order ˜ a few × 10 M⊙ even as the CR background strength varies by five orders of magnitude.

  3. The Simpson's paradox unraveled

    DEFF Research Database (Denmark)

    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....

  4. THE ROLE OF STYLISTIC MEANS IN CREATING PARADOX

    OpenAIRE

    Marina Vladimirovna Lekova

    2017-01-01

    Purpose. Despite the existence of massive scientific literature devoted to paradox this phenomenon does not seem to have received sufficient linguistic coverage. The purpose of the article is to describe stylistic mechanisms underlying paradoxical statements. The investigation was carried out on the material collected from the fairy tales by O. Wilde, the distinguished master of paradoxes. Methodology. The investigation is based on the methods of stylistic identification, classification a...

  5. Plume trajectory formation under stack tip self-enveloping

    Science.gov (United States)

    Gribkov, A. M.; Zroichikov, N. A.; Prokhorov, V. B.

    2017-10-01

    The phenomenon of stack tip self-enveloping and its influence upon the conditions of plume formation and on the trajectory of its motion are considered. Processes are described occurring in the initial part of the plume while the interaction between vertically directed flue gases outflowing from the stack and a horizontally directed moving air flow at high wind velocities that lead to the formation of a flag-like plume. Conditions responsible for the origin and evolution of interaction between these flows are demonstrated. For the first time, a plume formed under these conditions without bifurcation is registered. A photo image thereof is presented. A scheme for the calculation of the motion of a plume trajectory is proposed, the quantitative characteristics of which are obtained based on field observations. The wind velocity and direction, air temperature, and atmospheric turbulence at the level of the initial part of the trajectory have been obtained based on data obtained from an automatic meteorological system (mounted on the outer parts of a 250 m high stack no. 1 at the Naberezhnye Chelny TEPP plant) as well as based on the results of photographing and theodolite sighting of smoke puffs' trajectory taking into account their velocity within its initial part. The calculation scheme is supplemented with a new acting force—the force of self-enveloping. Based on the comparison of the new calculation scheme with the previous one, a significant contribution of this force to the development of the trajectory is revealed. A comparison of the natural full-scale data with the results of the calculation according to the proposed new scheme is made. The proposed calculation scheme has allowed us to extend the application of the existing technique to the range of high wind velocities. This approach would make it possible to simulate and investigate the trajectory and full rising height of the calculated the length above the mouth of flue-pipes, depending on various modal

  6. Electrical Tracking Formation on Silane Epoxy Resin under Various Contaminants

    Directory of Open Access Journals (Sweden)

    NFN Rochmadi

    2013-03-01

    Full Text Available Contamination at the surface of the insulator becomes a serious problem in power system operation, especially for the tropical area. Humidity and rainfall play an important role in wetness by the water at the surface of the insulator, which result in the presence of contaminant and leakage current flowing at the surface of the insulator. This leakage current will generate heat which occurs at the surface of an insulator, so that dry band area will be formed. This ultimately leads to flashover. This paper presents the influence of contaminants to leakage current and formation of electrical tracking at the surface of epoxy resin compound wit silicon rubber. The test was based on Inclined-Planed Tracking method with NH4Cl as contaminants. The industrial and coastal contaminants are used to explain the effect of contaminant at surface tracking process. The flow rate of contaminant was 0.3 ml/min. The 3.5 kV AC high voltage 50 Hz was applied to the top electrodes. It is found that industrial contamination resulting in the smallest surface leakage current is 327.6 mA. Also it is found that coastal contaminant (1420 mS/cm showed the severest damage at surface of test sample. Therefore, special treatment of the sample are needed under these conditions so that the material performance can be improved, especially against the electrical tracking.

  7. Regional modeling of SOA formation under consideration of HOMs

    Science.gov (United States)

    Gatzsche, Kathrin; Iinuma, Yoshiteru; Tilgner, Andreas; Berndt, Torsten; Poulain, Laurent; Wolke, Ralf

    2017-04-01

    Secondary organic aerosol (SOA) is the major burden of the atmospheric organic particulate matter with about 140 - 910 TgC/yr (Hallquist et al., 2009). SOA particles are formed via the oxidation of volatile organic carbons (VOCs), where the volatility of the VOCs is lowered. Therefore, gaseous compounds can either nucleate to form new particles or condense on existing particles. The framework of SOA formation under natural conditions is very complex, because there are a variety of gas-phase precursors, atmospheric degradation pathways and formed oxidation products. Up to now, atmospheric models underpredict the SOA mass. Therefore, improved regional scale model implementations are necessary to achieve a better agreement between model predictions and field measurements. Recently, highly oxidized multifunctional organic compounds (HOMs) were found in the gas phase from laboratory and field studies (Jokinen et al., 2015, Mutzel et al., 2015, Berndt et al., 2016a,b). From box model studies, it is known that HOMs are important for the early aerosol growth, however they are not yet considered in mechanisms applied in regional models. The present study utilizes the state-of-the-art multiscale model system COSMO-MUSCAT (Wolke et al., 2012), which is qualified for process studies in local and regional areas. The established model system was enhanced by a kinetic partitioning approach (Zaveri et al., 2014) for the gas-to-particle transfer of oxidized VOCs. The framework of the partitioning approach and the gas-phase mechanism were tested in a box model and evaluated with chamber studies, before implementing in the 3D model system COSMO-MUSCAT. Moreover, HOMs are implemented in the same way for the regional SOA modeling. 3D simulations were performed with an equilibrium partitioning and diffusion dependent partitioning approach, respectively. The presentation will provide first 3D simulation results including comparisons with field measurements from the TROPOS field site

  8. Parabolic Free Boundary Price Formation Models Under Market Size Fluctuations

    KAUST Repository

    Markowich, Peter A.

    2016-10-04

    In this paper we propose an extension of the Lasry-Lions price formation model which includes uctuations of the numbers of buyers and vendors. We analyze the model in the case of deterministic and stochastic market size uctuations and present results on the long time asymptotic behavior and numerical evidence and conjectures on periodic, almost periodic, and stochastic uctuations. The numerical simulations extend the theoretical statements and give further insights into price formation dynamics.

  9. Paradoxes of aging.

    Science.gov (United States)

    Blagosklonny, Mikhail V

    2007-12-15

    Insightful articles by Kirkwood and other outstanding scientists reveal paradoxes of aging. The source of paradoxes is an assumption that aging is caused by random, cumulative molecular damage. Here I demonstrate that a concept of TOR-driven program-like aging almost automatically resolves eleven paradoxes of aging. This article discusses why the accumulation of molecular damage does not limit life span, why calorie restriction and inhibition of protein synthesis extend life span, why the non-existing 'program' for aging is nevertheless robust, why a key gene for aging cannot be found by knocking it out, why low insulin is associated with good health but low insulin response with bad health, why aging is not a disease but can be treated as a disease, why 'healthy' aging is slow aging, and how we know that calorie restriction actually slows aging in humans.

  10. Nanodefect formation in LiF crystals under gamma irradiation

    International Nuclear Information System (INIS)

    Mussaeva, M.A.; Ibragimova, Eh.M.; Kalanov, M.U.; Muminov, M.I.

    2006-01-01

    One studied the spectra of absorption and of photoluminescence, microhardness and performed X-ray structure analysis of gamma-irradiated LiF crystals in a shutdown reactor and in 60 Co source when gamma-radiation dose rate was equal to 7.65 Gy/s. In addition to formation of point and combined radiation defects one detected the presence of the gamma-irradiation induced 28 nm size nanoparticles of LiOH phase in Li sublattice. Formation of defects is shown to occur more efficiently in a shutdown reactor in contrast to 60 Co source [ru

  11. Sand ripples under sea waves. Part 4. Tile ripple formation

    NARCIS (Netherlands)

    Roos, Pieter C.; Blondeaux, P.

    2001-01-01

    We investigate the formation of small-scale three-dimensional bedforms due to interactions of an erodible bed with a sea wave that obliquely approaches the coast, being partially reflected at the beach. In this case the trajectories of fluid particles at the top of the bottom boundary layer are

  12. Controlling rigid formations of mobile agents under inconsistent measurements

    NARCIS (Netherlands)

    Garcia de Marina Peinado, Hector; Cao, Ming; Jayawardhana, Bayu

    2015-01-01

    —Despite the great success of using gradient-based controllers to stabilize rigid formations of autonomous agents in the past years, surprising yet intriguing undesirable collective motions have been reported recently, when inconsistent measurements are used in the agents’ local controllers. To make

  13. A Magnetic Paradox

    Science.gov (United States)

    Arndt, Ebe

    2006-11-01

    Two recent articles1,2 in this journal described how an air core solenoid connected to an ac power source may restore the magnetization of a bar magnet with an alternating magnetic field (see Figs. 1 and 2). Although we are quite accustomed to using a constant magnetic field in an air core solenoid to remagnetize a ferromagnet, it is puzzling that we can also use an alternating magnetic field to realign the magnetic domains of a ferromagnet. To make the puzzle even more intriguing, the very same setup may be used to degauss a TV screen; that is, the alternating magnetic field of an air core solenoid can also "scramble" the magnetic domains of a ferromagnet! Although the latter phenomenon intuitively makes more sense, we are still left with a confusing paradox: How can an alternating magnetic field align the magnetic domains in one ferromagnet and scramble the magnetic domains in another? Paradoxes like these are ideal for student investigations because they create a natural interest. In fact, since the two articles mentioned above were unable to explain the magnetic paradox, my students and I were intrigued enough to investigate the phenomenon and then try to understand it theoretically. This paper describes how we used the paradoxical phenomenon for a student investigation into nonlinear systems. In order to be successful, students should be familiar with calculus, preferably at the level of an advanced-placement class.

  14. The Amazon's energetic paradox

    International Nuclear Information System (INIS)

    Silva, Marcos Vinicius Miranda da; Bermann, Celio

    1999-01-01

    The main energy sources in Amazon region are hydroelectric, biomass, and natural gas. Although abundance of these resources, the energy consumption in this region is one of the most low of Brazil. The article overviews this paradox. In this context, economical, geopolitical, and technical aspects are presented

  15. Adventures in Paradox

    Science.gov (United States)

    Lynch, Pip; Moore, Kevin

    2004-01-01

    The popularity of adventure recreation and adventure education has arisen, in part, from an assumption that adventure experiences are radically different from those of everyday life in modern societies. A paradox previously pointed out is that those seeking adventurous experiences often make use of technical and technological prosthetics, thus…

  16. A Hydrostatic Paradox Revisited

    Science.gov (United States)

    Ganci, Salvatore

    2012-01-01

    This paper revisits a well-known hydrostatic paradox, observed when turning upside down a glass partially filled with water and covered with a sheet of light material. The phenomenon is studied in its most general form by including the mass of the cover. A historical survey of this experiment shows that a common misunderstanding of the phenomenon…

  17. The Hydrostatic Paradox.

    Science.gov (United States)

    Wilson, Alpha E.

    1995-01-01

    Presents an example demonstrating the quantitative resolution of the hydrostatic paradox which is the realization that the force due to fluid pressure on the bottom of a vessel can be considerably greater or considerably less than the weight of the fluid in the vessel. (JRH)

  18. The happiness paradox

    NARCIS (Netherlands)

    Bollen, Johan; Gonçalves, Bruno; Leemput, van de Ingrid; Ruan, Guangchen

    2017-01-01

    Most individuals in social networks experience a so-called Friendship Paradox: they are less popular than their friends on average. This effect may explain recent findings that widespread social network media use leads to reduced happiness. However the relation between popularity and happiness is

  19. The nuclear paradox

    International Nuclear Information System (INIS)

    Eibenschutz, J.

    1989-01-01

    In this work it is discussed the nuclear paradox. One side, the nuclear power is important for technological development, on the other hand, it has been frequently questioned by society. It is pointed out as well, that many other factors are more dangerous to man such as environment polution. (A.C.A.S.)

  20. The Lunar orbit paradox

    Directory of Open Access Journals (Sweden)

    Tomić Aleksandar S.

    2013-01-01

    Full Text Available Newton's formula for gravity force gives greather force intensity for atraction of the Moon by the Sun than atraction by the Earth. However, central body in lunar (primary orbit is the Earth. So appeared paradox which were ignored from competent specialist, because the most important problem, determination of lunar orbit, was inmediately solved sufficiently by mathematical ingeniosity - introducing the Sun as dominant body in the three body system by Delaunay, 1860. On this way the lunar orbit paradox were not canceled. Vujičić made a owerview of principles of mechanics in year 1998, in critical consideration. As an example for application of corrected procedure he was obtained gravity law in some different form, which gave possibility to cancel paradox of lunar orbit. The formula of Vujičić, with our small adaptation, content two type of acceleration - related to inertial mass and related to gravity mass. So appears carried information on the origin of the Moon, and paradox cancels.

  1. New physics and paradox

    International Nuclear Information System (INIS)

    Van der Spuy, E.

    1983-01-01

    Conflict between the finite and infinite in theoretical physics often results in paradox. By measuring phenomena for which such conflict exists, physicists may be able to discover in each case the basis of the conflict and thus may eventually reformulate physical laws

  2. Obesity Paradox in the Course of Cerebrovascular Diseases.

    Science.gov (United States)

    Brzecka, Anna; Ejma, Maria

    2015-01-01

    Obesity remains an important risk factor of cardiovascular and cerebrovascular diseases. However, it has been observed that increased body fat and body mass index predicted longer survival after the occurrence of a cardiovascular event. This observation has been named the obesity paradox. Initially, the term obesity paradox referred to the observation of the better outcome of cardiovascular diseases, such as heart failure and coronary heart disease, in obese patients as compared to underweight and normal-weight patients. Recently, similar, although fewer, observations confirm the occurrence of the obesity paradox in patients with acute cerebrovascular diseases. The underlying reasons for the protective effects of excessive body fat tissue against the consequences of acute cardiovascular and cerebrovascular diseases are poorly understood. The effect of preconditioning may be associated with the obesity paradox. The issue of the correlation between obesity and better survival of patients with cardiovascular and cerebrovascular diseases still remains largely unexplored. Debates for and against the obesity paradox continue.

  3. Cumulative approaches to track formation under swift heavy ion (SHI) irradiation: Phenomenological correlation with formation energies of Frenkel pairs

    International Nuclear Information System (INIS)

    Crespillo, M.L.; Agulló-López, F.; Zucchiatti, A.

    2017-01-01

    Highlights: • Extensive survey formation energies Frenkel pairs and electronic stopping thresholds. • Correlation: track formation thresholds and the energies for Frenkel pair formation. • Formation energies Frenkel pairs discussed in relation to the cumulative mechanisms. • Amorphous track formation mechanisms: defect accumulation models versus melting. • Advantages cumulative models to deal with new hot topics: nuclear-electronic synergy. - Abstract: An extensive survey for the formation energies of Frenkel pairs, as representative candidates for radiation-induced point defects, is presented and discussed in relation to the cumulative mechanisms (CM) of track formation in dielectric materials under swift heavy ion (SHI) irradiation. These mechanisms rely on the generation and accumulation of point defects during irradiation followed by collapse of the lattice once a threshold defect concentration is reached. The physical basis of those approaches has been discussed by Fecht as a defect-assisted transition to an amorphous phase. Although a first quantitative analysis of the CM model was previously performed for LiNbO 3 crystals, we have, here, adopted a broader phenomenological approach. It explores the correlation between track formation thresholds and the energies for Frenkel pair formation for a broad range of materials. It is concluded that the threshold stopping powers can be roughly scaled with the energies required to generate a critical Frenkel pair concentration in the order of a few percent of the total atomic content. Finally, a comparison with the predictions of the thermal spike model is discussed within the analytical Szenes approximation.

  4. Cumulative approaches to track formation under swift heavy ion (SHI) irradiation: Phenomenological correlation with formation energies of Frenkel pairs

    Energy Technology Data Exchange (ETDEWEB)

    Crespillo, M.L., E-mail: mcrespil@utk.edu [Centro de Microanálisis de Materiales, CMAM-UAM, Cantoblanco, Madrid 28049 (Spain); Department of Materials Science & Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Agulló-López, F., E-mail: fal@uam.es [Centro de Microanálisis de Materiales, CMAM-UAM, Cantoblanco, Madrid 28049 (Spain); Zucchiatti, A. [Centro de Microanálisis de Materiales, CMAM-UAM, Cantoblanco, Madrid 28049 (Spain)

    2017-03-01

    Highlights: • Extensive survey formation energies Frenkel pairs and electronic stopping thresholds. • Correlation: track formation thresholds and the energies for Frenkel pair formation. • Formation energies Frenkel pairs discussed in relation to the cumulative mechanisms. • Amorphous track formation mechanisms: defect accumulation models versus melting. • Advantages cumulative models to deal with new hot topics: nuclear-electronic synergy. - Abstract: An extensive survey for the formation energies of Frenkel pairs, as representative candidates for radiation-induced point defects, is presented and discussed in relation to the cumulative mechanisms (CM) of track formation in dielectric materials under swift heavy ion (SHI) irradiation. These mechanisms rely on the generation and accumulation of point defects during irradiation followed by collapse of the lattice once a threshold defect concentration is reached. The physical basis of those approaches has been discussed by Fecht as a defect-assisted transition to an amorphous phase. Although a first quantitative analysis of the CM model was previously performed for LiNbO{sub 3} crystals, we have, here, adopted a broader phenomenological approach. It explores the correlation between track formation thresholds and the energies for Frenkel pair formation for a broad range of materials. It is concluded that the threshold stopping powers can be roughly scaled with the energies required to generate a critical Frenkel pair concentration in the order of a few percent of the total atomic content. Finally, a comparison with the predictions of the thermal spike model is discussed within the analytical Szenes approximation.

  5. Professions, paradoxes and organizing

    DEFF Research Database (Denmark)

    Juel Jacobsen, Alice

    an ethnographic approach and a concept of paradox as an exploring lens, the paper investigates the micro processes at work. The results of the empirical research point to challenging basic assumptions generated by the classical professions’ theory of autonomous and self-reliant professions. The paper contributes......This paper empirically investigates organizational change in the making as it is constructed in the interaction between managers and professions in a school setting. The empirical basis is three Danish upper secondary schools, all in the process of translating a school reform into practice. Using...... to clarify the particular tensions and paradoxes that emerge in the relational management processes and adds to our understanding of management of professions in schools....

  6. Paradoxes in Biodiversity Conservation

    OpenAIRE

    David Pearce

    2005-01-01

    Biodiversity is important for human wellbeing, but it is declining. Measures to conserve biodiversity are essential but may be a waste of effort if several paradoxes are not addressed. The highest levels of diversity are in nations least able to practise effective conservation. The flow of funds to international biodiversity conservation appears trivial when compared to the scale of biodiversity loss. International agreements may not actually protect or conserve more than what would have been...

  7. The bosonic birthday paradox

    OpenAIRE

    Arkhipov, Alex; Kuperberg, Greg

    2011-01-01

    We motivate and prove a version of the birthday paradox for $k$ identical bosons in $n$ possible modes. If the bosons are in the uniform mixed state, also called the maximally mixed quantum state, then we need $k \\sim \\sqrt{n}$ bosons to expect two in the same state, which is smaller by a factor of $\\sqrt{2}$ than in the case of distinguishable objects (boltzmannons). While the core result is elementary, we generalize the hypothesis and ...

  8. The Paradoxes of Liberalism

    DEFF Research Database (Denmark)

    Thompson, Grahame

    2011-01-01

    Jakob Vestergaard has produced one of the most telling analyses of the international financial architecture by deploying a broadly Foucauldian framework that invokes a novel description of neo-liberal governance, one organized around discipline, conditional exceptions and the pursuit of a ‘proper...... economy’. This review both welcomes but challenges some of Vestergaard's analysis. In so doing it explores further the paradoxes of liberalism and the fate of sovereignty in the current international context....

  9. Hydrogen formation under gamma and heavy ions irradiation of geopolymers

    International Nuclear Information System (INIS)

    Chupin, F.; Dannoux-Papin, A.; D'Espinose de Lacaillerie, J.B.; Ngono Ravache, Y.

    2015-01-01

    This study examines the behavior under irradiation of geo-polymer which is not yet well known and attempts to highlight the importance of water radiolysis. For their use as embedding matrices, stability under ionizing radiation as well as low hydrogen gas released must be demonstrated. Different formulations of geo-polymers have been irradiated either with γ-rays ( 60 Co sources) or 75 MeV 36 Ar ions beams and the production of hydrogen released has been quantified. This paper presents the results of gas analysis in order to identify important structural parameters that influence confined water radiolysis. Indeed, a correlation between pore size, water content on one side, and the hydrogen production radiolytic yield (G(H 2 )) on the other side, has been demonstrated. For the 75 MeV 36 Ar ions irradiation, the effect of porosity has not been well emphasized. For both, the results have revealed the water content influence. (authors)

  10. Emotional Memory Formation Under Lower Versus Higher Stress Conditions

    OpenAIRE

    Kogan, Inna; Richter-Levin, Gal

    2010-01-01

    An exposure to stress can enhance memory for emotionally arousing experiences. The phenomenon is suggested to be amygdala-dependent and in accordance with that view the amygdala was found to modulate mnemonic processes in other brain regions. Previously, we illustrated increased amygdala activation and reduced activation of CA1 following spatial learning under higher versus lower stress conditions. When spatial learning was followed by reversal training interference, impaired retention was de...

  11. Hydrogen formation and control under postulated LMFBR accident conditions

    International Nuclear Information System (INIS)

    Armstrong, G.R.; Wierman, R.W.

    1976-09-01

    The objective of this study is to experimentally investigate the potential for autoignition and combustion of hydrogen-sodium mixtures which may be produced in LMFBR accidents. The purpose and ultimate usefulness of this work is to provide data that will establish the validity and acceptability of mechanisms inherent to the LMFBR that could either prevent or delay the accumulation of hydrogen gas to less than 4 percent (V) in the Reactor Containment Building (RCB) under accident conditions. The results to date indicate that sodium and sodium-hydrogen mixtures such as may be expected during LMFBR postulated accidents will ignite upon entering an air atmosphere and that the hydrogen present will be essentially all consumed until such time that the oxygen concentration is depleted

  12. Earth's inner core nucleation paradox

    Science.gov (United States)

    Huguet, Ludovic; Van Orman, James A.; Hauck, Steven A.; Willard, Matthew A.

    2018-04-01

    The conventional view of Earth's inner core is that it began to crystallize at Earth's center when the temperature dropped below the melting point of the iron alloy and has grown steadily since that time as the core continued to cool. However, this model neglects the energy barrier to the formation of the first stable crystal nucleus, which is commonly represented in terms of the critical supercooling required to overcome the barrier. Using constraints from experiments, simulations, and theory, we show that spontaneous crystallization in a homogeneous liquid iron alloy at Earth's core pressures requires a critical supercooling of order 1000 K, which is too large to be a plausible mechanism for the origin of Earth's inner core. We consider mechanisms that can lower the nucleation barrier substantially. Each has caveats, yet the inner core exists: this is the nucleation paradox. Heterogeneous nucleation on a solid metallic substrate tends to have a low energy barrier and offers the most straightforward solution to the paradox, but solid metal would probably have to be delivered from the mantle and such events are unlikely to have been common. A delay in nucleation, whether due to a substantial nucleation energy barrier, or late introduction of a low energy substrate, would lead to an initial phase of rapid inner core growth from a supercooled state. Such rapid growth may lead to distinctive crystallization texturing that might be observable seismically. It would also generate a spike in chemical and thermal buoyancy that could affect the geomagnetic field significantly. Solid metal introduced to Earth's center before it reached saturation could also provide a nucleation substrate, if large enough to escape complete dissolution. Inner core growth, in this case, could begin earlier and start more slowly than standard thermal models predict.

  13. The Teacher's Paradox

    Science.gov (United States)

    Lilyquist, J. Gary

    1998-06-01

    New findings suggest that the way in which schools conduct their business is blocking our educational system from improving at a rate required to meet society's needs. A ground theory developed by exploring six organizational dimensions: external and internal environment cultures, leadership, strategy, structure, and results, verified the existence of the teacher's paradox. Implications suggest educational reformers must rethink approaches to school improvement by work within cultural boundaries. The forth coming book, "Are schools really like this?" presents "The Balance Alignment Model and Theory" to improve our schools using system thinking.

  14. Preparedness Formation of the Future Vocational Education Teachers to Occupational Adaptation under Conditions of Globalization Processes

    Science.gov (United States)

    Sushentseva, Liliya

    2014-01-01

    The problem of the preparedness formation of future teachers of vocational training to the professional adaptation under conditions of globalization processes in society is considered. The analysis of scientific and educational literature devoted to the study of occupational adaptation and preparedness formation of specialists to it is carried…

  15. Barn and Pole Paradox: Revisited

    Science.gov (United States)

    Cacioppo, Robert; Gangopadhyaya, Asim

    2012-01-01

    Paradoxes have played great instructive roles in many cultures. They provide an excellent paradigm for teaching concepts that require deep reflection. In this article, the authors present two different paradoxes related to the length contraction in special relativity and explain their resolution. They hope that these two Gedanken experiments and…

  16. Unearthing the Banach–Tarski Paradox

    Indian Academy of Sciences (India)

    This goes under the name of Banach–Tarski paradox. The whole magic lies in the word 'pieces'. The pieces ... tinct classes. Let us select one representative point f(¯x) in [0,1) corresponding to each class ¯x. ... ble as 0 ≤ r(n) < r(m) < 1 and E contains only one element from any class. Therefore, we have proved our claims, ...

  17. Paradoxes in aerohydrodynamics

    CERN Document Server

    Yershin, Shakhbaz A

    2017-01-01

    This book, on the general topic of hydroaerodynamics, investigates a number of exciting applications in this field, addressing specifically issues that allow seemingly paradoxical issues to be dealt with. The first part is devoted to the study of channel flows, in particular the lateral flow of a viscous and viscous-plastic liquid in a ring channel formed by coaxial cylinders. Specifically, the problem of dissipation of mechanical energy in channel flows of highly viscous liquids is addressed and solved. Furthermore, the mechanism leading to hydrodynamic erosion in intra-field pipelines (known as "channelized effect") is identified. Subsequently, a theory for channel flows with mass transfer through porous walls is developed. In the second part, viscous liquid free flows (jets) are investigated. In particular, a dispersion law for turbulent flow is derived and the existence of dynamic invariance in wake flows of variable density is demonstrated. The third part presents new insights from both theoretical and e...

  18. Plotting Gothic: A Paradox

    Directory of Open Access Journals (Sweden)

    Stephen Murray

    2014-06-01

    Full Text Available The paradox of the title is that while most historians of medieval architecture agree that a combination of geometric and arithmetic methods was generally used to lay out a medieval church, there has been little consensus on the specifics of the process in relation to the design of any particular edifice. I begin by identifying four premises which underlie the debate. I then ask whether the new technologies — laser scanning and computer assisted design/drafting applications — can help. A case study uses newly generated point cloud data from a laser scan of the choir of Beauvais Cathedral. Finally, the notion of ‘plotting’ introduces essential sociological, anthropological and rhetorical dimensions. In the spirit of Roland Barthes ('Le plaisir du texte' and Peter Brooks ('Reading for the Plot', we can understand the urgency with which the architectural historian may seek to unscramble the hidden codes of the building as compulsive ‘reading for the plot’.

  19. Mimesis, fiction, paradoxes

    Directory of Open Access Journals (Sweden)

    Françoise Lavocat

    2010-04-01

    Full Text Available Les théories contemporaines de la fiction, comme les poétiques de la Renaissance, privilégient une conception de la mimesis fondée sur la vraisemblance : la démonstration du profit cognitif et moral de la fiction passe toujours par une définition de l’imitation (de quelque façon qu’on la définisse fondée sur la rationalité. L’auteur de cet article examine tout d’abord le statut des contradictions et de l’impossible chez quelques théoriciens actuels (principalement J.-M. Schaeffer, M.-L. Ryan, L. Doležel et poéticiens du 16e siècle (L. Castelvetro et F. Patrizi. Sont ensuite étudiées la forme et la fonction que prend l’impossible dans trois fictions narratives de la Renaissance. L’hypothèse majeure qui est défendue est que ces paradoxes permettent de penser le non-existant, dans la continuité de la scolastique médiévale et en relation avec une problématique religieuse, sérieuse ou parodique. Par là même, et en raison de leur auto-référentialité constitutive, les paradoxes inscrivent dans la fiction une réflexion sur elle-même qui n’a rien d’une apologie. La pensée de la fiction s’articule en définitive de façon bien différente dans les théories et dans les fictions elles-mêmes.Like Renaissance poetics, contemporary theories of fiction do favour a conception of mimesis based on likelihood. In order to underscore the benefits of fiction, in terms of cognition or ethics, both ancient and present-day authors usually identify imitation (however this is understood as a kind of rationality. The aim of this article is to question the status of contradictions and impossibilities, first in current theories of fiction (J-M Schaeffer, M.-L. Ryan, L. Doležel, then in two sixteenth century comments of Aristotle (by L. Castelvetro and F. Patrizi. In the following steps, forms and functions of the impossible are studied in three narratives of the Renaissance. The main hypothesis here is the following: in

  20. Fantaisies et paradoxes mathématiques

    CERN Document Server

    Northrop, E P

    1964-01-01

    Qu'est-ce qu'un paradoxe ? ; quelques casse-tête simples (paradoxes pour tous) ; le puissant petit 2 et autres miracles... (paradoxes en arithmétique) ; je le vois, je ne le vois plus... (paradoxes en géométrie) ; tu ne diviseras pas par zéro... (sophismes algébriques) ; le voir, c'est le croire. Peut-être... (sophismes géométriques) ; toujours plus loin... (paradoxes de l'infini) ; combien de chances ? (paradoxes en probabilité) ; cercles vicieux (paradoxes en logique).

  1. Consciousness and the "Causal Paradox"

    OpenAIRE

    Velmans, Max

    1996-01-01

    Viewed from a first-person perspective consciousness appears to be necessary for complex, novel human activity - but viewed from a third-person perspective consciousness appears to play no role in the activity of brains, producing a "causal paradox". To resolve this paradox one needs to distinguish consciousness of processing from consciousness accompanying processing or causing processing. Accounts of consciousness/brain causal interactions switch between first- and third-person perspectives...

  2. Sleep Education for Paradoxical Insomnia

    OpenAIRE

    Geyer, James D.; Lichstein, Kenneth L.; Ruiter, Megan E.; Ward, L. Charles; Carney, Paul R.; Dillard, Stephenie C.

    2011-01-01

    This case study series investigated a new treatment for paradoxical insomnia patients as there is no standard treatment for this patient group at this time. Four paradoxical insomnia patients had a polysomnography (PSG) sleep study, an unsuccessful brief course of behavioral treatment for insomnia, and then a novel sleep education treatment comprising review of their PSG with video and exploration of the discrepancy between their reported and observed sleep experience. Two patients responded ...

  3. Paradoxical therapy in conversion disorder

    OpenAIRE

    ATAOĞLU, Ahmet

    1998-01-01

    Paradoxical therapy consists of suggesting that the patient intentionally engages in the unwanted behaviour, such as performing complusive ritual or bringing on a conversion attack. In this study paradoxical intention (PI) was used with to half of the patients with conversion disorders, while the other half were treated with diazepam in order to examine the efficiency of the PI versus diazepam in conversion disorder. Patients treated with PI appeared to have a greater improvement r...

  4. Altruism and the Transfer Paradox

    OpenAIRE

    Hamada, Kojun

    2011-01-01

    This paper examines whether altruism causes the transfer paradox in the model with two countries and two goods when the consumers of the donor and recipient countries have altruistic utility. We demonstrate that if the Walrasian stability condition is satisfied in the general equilibrium, the transfer paradox can never take place irrespective of the definition of utility. The result suggests that the motivation for transfer cannot beexplained by the donor's enrichment because it is not caused...

  5. Pd-based alloy nanoclusters in ion-implanted silica: Formation and stability under thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Battaglin, G.; Cattaruzza, E.; De Marchi, G.; Gonella, F.; Mattei, G. E-mail: mattei@padova.infm.it; Maurizio, C.; Mazzoldi, P.; Parolin, M.; Sada, C.; Calliari, I

    2002-05-01

    In this work we report on the formation and stability under thermal annealing of Pd-Cu and Pd-Ag alloy nanoclusters obtained by sequential ion implantation in silica. The role of the annealing atmosphere on the alloy cluster formation and stability is investigated. A comparison is made with similar alloy-based systems obtained by sequential ion implantation in silica of Au-Ag or Au-Cu followed by annealing under similar conditions, in order to evidence the peculiar effect of the various metals in controlling the alloy evolution and/or decomposition.

  6. Iron and the oxygen paradox in ischemic hearts

    NARCIS (Netherlands)

    A. Voogd (Arthur)

    1993-01-01

    textabstractReintroduction of oxygen into ischemic tissue causes the formation of reactive oxygen species among which the oxygen radicals. This contributes to the tissue injwy that becomes apparent upon reperfusion. The phenomenon is known as the oxygen paradox. It is known that iron enhances the

  7. The paradox of strategic environmental assessment

    International Nuclear Information System (INIS)

    Bidstrup, Morten; Hansen, Anne Merrild

    2014-01-01

    Strategic Environmental Assessment (SEA) is a tool that can facilitate sustainable development and improve decision-making by introducing environmental concern early in planning processes. However, various international studies conclude that current planning practice is not taking full advantage of the tool, and we therefore define the paradox of SEA as the methodological ambiguity of non-strategic SEA. This article explores causality through at three-step case study on aggregates extraction planning in Denmark, which consists of a document analysis; a questionnaire survey and follow-up communication with key planners. Though the environmental reports on one hand largely lack strategic considerations, practitioners express an inherent will for strategy and reveal that their SEAs in fact have been an integrated part of the planning process. Institutional context is found to be the most significant barrier for a strategy and this suggests that non-strategic planning setups can prove more important than non-strategic planning in SEA practice. Planners may try to execute strategy within the confinements of SEA-restricted planning contexts; however, such efforts can be overlooked if evaluated by a narrow criterion for strategy formation. Consequently, the paradox may also spark from challenged documentation. These findings contribute to the common understanding of SEA quality; however, further research is needed on how to communicate and influence the strategic options which arguably remain inside non-strategic planning realities. - Highlights: • International studies conclude that SEAs are not strategic. = The paradox of SEA. • Even on the highest managerial level, some contexts do not leave room for strategy. • Non-strategic SEA can derive from challenged documentation. • Descriptive and emergent strategy formation can, in practice, be deemed non-strategic

  8. The paradox of comfort.

    Science.gov (United States)

    Morse, J M; Bottorff, J L; Hutchinson, S

    1995-01-01

    Patients who had experienced major illness, surgery, or trauma were asked to "tell their stories." Using a phenomenological method, eight themes emerged that reflected the experience of the lived body (corporeality) associated with discomfort. These were the dis-eased body, the disobedient body, the deceiving body, the vulnerable body, the violated body, the resigned body, the enduring body, and the betraying body. To patients, comfort is not an ultimate state of peace and serenity, but rather the relief, even temporary relief, from the most demanding discomfort. Illness and injury place patients' bodies into the foreground, dominating their attention and disrupting their accustomed orientation to the world. Thus, an understanding of patient comfort that is linked with discomfort and empowers or strengthens patients in relation to their bodies provides important insight. The authors argue that attaining comfort is a paradox best understood by reflecting not on the concept of comfort per se, but on its converse. This supports, rather than negates, the construct of comfort as the goal of nursing care.

  9. Neutral molecular cluster formation of sulfuric acid–dimethylamine observed in real time under atmospheric conditions

    CERN Document Server

    Kürten, Andreas; Simon, Mario; Sipilä, Mikko; Sarnela, Nina; Junninen, Heikki; Adamov, Alexey; Almeida, João; Amorim, Antonio; Bianchi, Federico; Breitenlechner, Martin; Dommen, Josef; Donahue, Neil M; Duplissy, Jonathan; Ehrhart, Sebastian; Flagan, Richard C; Franchin, Alessandro; Hakala, Jani; Hansel, Armin; Heinritzi, Martin; Hutterli, Manuel; Kangasluoma, Juha; Kirkby, Jasper; Laaksonen, Ari; Lehtipalo, Katrianne; Leiminger, Markus; Makhmutov, Vladimir; Mathot, Serge; Onnela, Antti; Petäjä, Tuukka; Praplan, Arnaud P; Riccobono, Francesco; Rissanen, Matti P; Rondo, Linda; Schobesberger, Siegfried; Seinfeld, John H; Steiner, Gerhard; Tomé, António; Tröstl, Jasmin; Winkler, Paul M; Williamson, Christina; Wimmer, Daniela; Ye, Penglin; Baltensperger, Urs; Carslaw, Kenneth S; Kulmala, Markku; Worsnop, Douglas R; Curtius, Joachim

    2014-01-01

    For atmospheric sulfuric acid (SA) concentrations the presence of dimethylamine (DMA) at mixing ratios of several parts per trillion by volume can explain observed boundary layer new particle formation rates. However, the concentration and molecular composition of the neutral (uncharged) clusters have not been reported so far due to the lack of suitable instrumentation. Here we report on experiments from the Cosmics Leaving Outdoor Droplets chamber at the European Organization for Nuclear Research revealing the formation of neutral particles containing up to 14 SA and 16 DMA molecules, corresponding to a mobility diameter of about 2 nm, under atmospherically relevant conditions. These measurements bridge the gap between the molecular and particle perspectives of nucleation, revealing the fundamental processes involved in particle formation and growth. The neutral clusters are found to form at or close to the kinetic limit where particle formation is limited only by the collision rate of SA molecules. Even tho...

  10. Visualization of hot spot formation in energetic materials under periodic mechanical excitation using phosphor thermography

    Science.gov (United States)

    Casey, Alex; Fenoglio, Gabriel; Detrinidad, Humberto

    2017-06-01

    Under mechanical excitation, energy is known to localize within an energetic material resulting in `hot spot' formation. While many formation mechanisms have been proposed, additional insight to heat generation mechanisms, the effect of binder/crystal interfaces, and predication capabilities can be gained by quantifying the initiation and growth of the hot spots. Phosphor thermography is a well established temperature sensing technique wherein an object's temperature is obtained by collecting the temperature dependent luminescence of an optically excited phosphor. Herein, the phosphor thermography technique has been applied to Dow Corning Sylgard® 184/octahydro 1,3,5,7 tetranitro 1,3,5,7 tetrazocine (HMX) composite materials under mechanical excitation in order to visualize the evolution of the temperature field, and thus hot spot formation, within the binder. Funded by AFOSR. Supported by the Department of Defense (DoD) through the National Defense Science & Engineering Graduate Fellowship (NDSEG) Program.

  11. Hydrothermal formation of tobermorite studied by in situ X-ray diffraction under autoclave condition.

    Science.gov (United States)

    Kikuma, Jun; Tsunashima, Masamichi; Ishikawa, Tetsuji; Matsuno, Shin-ya; Ogawa, Akihiro; Matsui, Kunio; Sato, Masugu

    2009-09-01

    Hydrothermal formation of tobermorite from a pre-cured cake has been investigated by transmission X-ray diffraction (XRD) using high-energy X-rays from a synchrotron radiation source in combination with a newly designed autoclave cell. The autoclave cell has a large and thin beryllium window for wide-angle X-ray diffraction; nevertheless, it withstands a steam pressure of more than 1.2 MPa, which enables in situ XRD measurements in a temperature range of 373 to 463 K under a saturated steam pressure. Formation and/or decomposition of several components has been successfully observed during 7.5 h of reaction time. From the intensity changes of the intermediate materials, namely non-crystalline C-S-H and hydroxylellestadite, two pathways for tobermorite formation have been confirmed. Thus, the newly developed autoclave cell can be used for the analyses of reaction mechanisms under specific atmospheres and temperatures.

  12. Paradoxes and Innovation in Family Firms

    DEFF Research Database (Denmark)

    Ingram, Amy E.; Lewis, Marianne W.; Barton, Sid

    2016-01-01

    Scholars stress that family firms are inherently paradoxical, and that tensions, such as tradition versus change, family liquidity versus business growth, and founder control versus successor autonomy, can both inhibit and foster innovation. Further, theorists propose that firms led by paradoxica...... indicate that paradoxical tensions may stymie innovative behavior, but that leaders' paradoxical thinking is positively related to innovative behavior....... thinkers are more likely to manage these tensions and fuel innovative behavior. Leveraging family business and organizational paradox literatures, this multi-stage exploratory study develops measures of paradoxical tensions and paradoxical thinking in family firms, and tests these propositions. Findings...

  13. Law of the Minimum paradoxes.

    Science.gov (United States)

    Gorban, Alexander N; Pokidysheva, Lyudmila I; Smirnova, Elena V; Tyukina, Tatiana A

    2011-09-01

    The "Law of the Minimum" states that growth is controlled by the scarcest resource (limiting factor). This concept was originally applied to plant or crop growth (Justus von Liebig, 1840, Salisbury, Plant physiology, 4th edn., Wadsworth, Belmont, 1992) and quantitatively supported by many experiments. Some generalizations based on more complicated "dose-response" curves were proposed. Violations of this law in natural and experimental ecosystems were also reported. We study models of adaptation in ensembles of similar organisms under load of environmental factors and prove that violation of Liebig's law follows from adaptation effects. If the fitness of an organism in a fixed environment satisfies the Law of the Minimum then adaptation equalizes the pressure of essential factors and, therefore, acts against the Liebig's law. This is the the Law of the Minimum paradox: if for a randomly chosen pair "organism-environment" the Law of the Minimum typically holds, then in a well-adapted system, we have to expect violations of this law.For the opposite interaction of factors (a synergistic system of factors which amplify each other), adaptation leads from factor equivalence to limitations by a smaller number of factors.For analysis of adaptation, we develop a system of models based on Selye's idea of the universal adaptation resource (adaptation energy). These models predict that under the load of an environmental factor a population separates into two groups (phases): a less correlated, well adapted group and a highly correlated group with a larger variance of attributes, which experiences problems with adaptation. Some empirical data are presented and evidences of interdisciplinary applications to econometrics are discussed. © Society for Mathematical Biology 2010

  14. CosmoBon for studying wood formation under exotic gravitational environment for future space agriculture

    Science.gov (United States)

    Tomita-Yokotani, Kaori; Baba, Keiichi; Suzuki, Toshisada; Funada, Ryo; Nakamura, Teruko; Hashimoto, Hirofumi; Yamashita, Masamichi; Cosmobon, Jstwg

    We are proposing to raise woody plants in space for several applications and plant science. Japanese flowering cherry tree is one of a candidate for these studies. Mechanism behind sensing gravity and controlling shape of tree has been studied quite extensively. Even molecular mechanism for the response of plant against gravity has been investigated quite intensively for various species, woody plants are left behind. Morphology of woody branch growth is different from that of stem growth in herbs. Morphology in tree is strongly dominated by the secondary xylem formation. Nobody knows the tree shape grown under the space environment. If whole tree could be brought up to space as research materials, it might provide important scientific knowledge. Furthermore, trees produce excess oxygen, wooden materials for living cabin, and provide biomass for cultivating mushroom and insect as for the space agriculture. Excellent tree shapes which would be deeply related to wood formation improve quality of life under stressful environment in outer space. The serious problem would be their size. Bonsai is one of the Japanese traditional arts. We can study secondly xylem formation, wood formation, under exotic gravitational environment using Bonsai. "CosmoBon" is the small tree Bonsai for our space experiment. It has been recognized that the reaction wood in CosmoBon is formed similar to natural trees. Our goal is to examine feasibility to grow various species of trees in space as bioresource for space agriculture.

  15. Neutral molecular cluster formation of sulfuric acid–dimethylamine observed in real time under atmospheric conditions

    Science.gov (United States)

    Kürten, Andreas; Jokinen, Tuija; Simon, Mario; Sipilä, Mikko; Sarnela, Nina; Junninen, Heikki; Adamov, Alexey; Almeida, João; Amorim, Antonio; Bianchi, Federico; Breitenlechner, Martin; Dommen, Josef; Donahue, Neil M.; Duplissy, Jonathan; Ehrhart, Sebastian; Flagan, Richard C.; Franchin, Alessandro; Hakala, Jani; Hansel, Armin; Heinritzi, Martin; Hutterli, Manuel; Kangasluoma, Juha; Kirkby, Jasper; Laaksonen, Ari; Lehtipalo, Katrianne; Leiminger, Markus; Makhmutov, Vladimir; Mathot, Serge; Onnela, Antti; Petäjä, Tuukka; Praplan, Arnaud P.; Riccobono, Francesco; Rissanen, Matti P.; Rondo, Linda; Schobesberger, Siegfried; Seinfeld, John H.; Steiner, Gerhard; Tomé, António; Tröstl, Jasmin; Winkler, Paul M.; Williamson, Christina; Wimmer, Daniela; Ye, Penglin; Baltensperger, Urs; Carslaw, Kenneth S.; Kulmala, Markku; Worsnop, Douglas R.; Curtius, Joachim

    2014-01-01

    For atmospheric sulfuric acid (SA) concentrations the presence of dimethylamine (DMA) at mixing ratios of several parts per trillion by volume can explain observed boundary layer new particle formation rates. However, the concentration and molecular composition of the neutral (uncharged) clusters have not been reported so far due to the lack of suitable instrumentation. Here we report on experiments from the Cosmics Leaving Outdoor Droplets chamber at the European Organization for Nuclear Research revealing the formation of neutral particles containing up to 14 SA and 16 DMA molecules, corresponding to a mobility diameter of about 2 nm, under atmospherically relevant conditions. These measurements bridge the gap between the molecular and particle perspectives of nucleation, revealing the fundamental processes involved in particle formation and growth. The neutral clusters are found to form at or close to the kinetic limit where particle formation is limited only by the collision rate of SA molecules. Even though the neutral particles are stable against evaporation from the SA dimer onward, the formation rates of particles at 1.7-nm size, which contain about 10 SA molecules, are up to 4 orders of magnitude smaller compared with those of the dimer due to coagulation and wall loss of particles before they reach 1.7 nm in diameter. This demonstrates that neither the atmospheric particle formation rate nor its dependence on SA can simply be interpreted in terms of cluster evaporation or the molecular composition of a critical nucleus. PMID:25288761

  16. Predicting hydrocarbon potential of an earth formation underlying a body of water

    International Nuclear Information System (INIS)

    Kaplan, I.R.; Demaison, G.J.

    1983-01-01

    A method for the on-site collection and examination of small concentrations of methane dissolved in water so as to predict hydrocarbon potential of an earth formation underlying a body of water, said formation being a source of said methane, comprises: (i) sampling the water; (ii) continuously vacuum separating said water into liquid and gas phases; (iii) quantitatively separating interfering gas species from methane; (iv) quantitatively oxidising said methane; (v) cryogenically trapping the resulting gaseous carbon dioxide and water vapor at a trapping station, and (vi) isotopically examining said trapped carbon dioxide and water vapour for carbon and deuterium distribution. (author)

  17. Bacterial exopolysaccharide and biofilm formation stimulate chickpea growth and soil aggregation under salt stress

    Directory of Open Access Journals (Sweden)

    Aisha Waheed Qurashi

    2012-09-01

    Full Text Available To compensate for stress imposed by salinity, biofilm formation and exopolysaccharide production are significant strategies of salt tolerant bacteria to assist metabolism. We hypothesized that two previously isolated salt-tolerant strains Halomonas variabilis (HT1 and Planococcus rifietoensis (RT4 have an ability to improve plant growth, These strains can form biofilm and accumulate exopolysacharides at increasing salt stress. These results showed that bacteria might be involved in developing microbial communities under salt stress and helpful in colonizing of bacterial strains to plant roots and soil particles. Eventually, it can add to the plant growth and soil structure. We investigated the comparative effect of exopolysacharide and biofilm formation in two bacterial strains Halomonas variabilis (HT1 and Planococcus rifietoensis (RT4 in response to varying salt stress. We found that biofilm formation and exopolysaccharide accumulation increased at higher salinity. To check the effect of bacterial inoculation on the plant (Cicer arietinum Var. CM-98 growth and soil aggregation, pot experiment was conducted by growing seedlings under salt stress. Inoculation of both strains increased plant growth at elevated salt stress. Weight of soil aggregates attached with roots and present in soil were added at higher salt concentrations compared to untreated controls. Soil aggregation was higher at plant roots under salinity. These results suggest the feasibility of using above strains in improving plant growth and soil fertility under salinity.

  18. The paradox of scientific expertise

    DEFF Research Database (Denmark)

    Alrøe, Hugo Fjelsted; Noe, Egon

    2011-01-01

    Modern societies depend on a growing production of scientific knowledge, which is based on the functional differentiation of science into still more specialised scientific disciplines and subdisciplines. This is the basis for the paradox of scientific expertise: The growth of science leads to a f...... cross-disciplinary research and in the collective use of different kinds of scientific expertise, and thereby make society better able to solve complex, real-world problems.......Modern societies depend on a growing production of scientific knowledge, which is based on the functional differentiation of science into still more specialised scientific disciplines and subdisciplines. This is the basis for the paradox of scientific expertise: The growth of science leads...... to a fragmentation of scientific expertise. To resolve this paradox, the present paper investigates three hypotheses: 1) All scientific knowledge is perspectival. 2) The perspectival structure of science leads to specific forms of knowledge asymmetries. 3) Such perspectival knowledge asymmetries must be handled...

  19. Four paradoxes about the special theory of relativity

    OpenAIRE

    Li, Xiao-Jun; Chen, Kai; Li, Xiao-Niu; Li, Yong-An

    2016-01-01

    Various paradoxes about the relativity theory have been developed since the birth of this theory. Each paradox somewhat shows people's query about the relativity theory, and solving of each paradox demonstrates the correctness of relativity theory once again. In this paper, four paradoxes about the special theory of relativity are brought forward: displacement paradox, electromagnetic transformation paradox, Doppler paradox and magnetic force paradox. We hope some researchers can reasonably e...

  20. Biofilm formation, phenotypic production of cellulose and gene expression in Salmonella enterica decrease under anaerobic conditions.

    Science.gov (United States)

    Lamas, A; Miranda, J M; Vázquez, B; Cepeda, A; Franco, C M

    2016-12-05

    Salmonella enterica subsp. enterica is one of the main food-borne pathogens. This microorganism combines an aerobic life outside the host with an anaerobic life within the host. One of the main concerns related to S. enterica is biofilm formation and cellulose production. In this study, biofilm formation, morphotype, cellulose production and transcription of biofilm and quorum sensing-related genes of 11 S. enterica strains were tested under three different conditions: aerobiosis, microaerobiosis, and anaerobiosis. The results showed an influence of oxygen levels on biofilm production. Biofilm formation was significantly higher (Penterica strains tested. This gene expression levels were less reduced in S. Typhimurium and S. Enteritidis compared to the tested serotypes. There was a relationship between the expression of biofilm and quorum sensing-related genes. Thus, the results from this study indicate that biofilm formation and cellulose production are highly influenced by atmospheric conditions. This must be taken into account as contamination with these bacteria can occur during food processing under vacuum or modified atmospheres. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Fresh garlic extract inhibits Staphylococcus aureus biofilm formation under chemopreventive and chemotherapeutic conditions

    Directory of Open Access Journals (Sweden)

    Panan Ratthawongjirakul

    2016-08-01

    Full Text Available Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA are the leading aetiological pathogens of nosocomial infections worldwide. These bacteria form biofilms on both biotic and abiotic surfaces causing biofilm-associated infections. Within the biofilm, these bacteria might develop persistent and antimicrobial resistant characteristics resulting in chronic infections and treatment failures. Garlic exhibits broad pharmaceutical properties and inhibitory activities against S. aureus. We investigated the effects of aqueous fresh garlic extract on biofilm formation in S. aureus ATCC25923 and MRSA strains under chemopreventive and chemotherapeutic conditions. The viable bacteria and biofilm levels were quantified through colony count and crystal violet staining, respectively. The use of fresh garlic extract under both conditions significantly inhibited biofilm formation in S. aureus strains ATCC25923 and MRSA. Garlic could be developed as either a prophylactic or therapeutic agent to manage S. aureus biofilm-associated infections.

  2. The Formation of Carbon Nanostructures via Catalytic Pyrolysis of Naphthalene under Its Autogenic Pressure

    Directory of Open Access Journals (Sweden)

    Chao-Gang Wang

    2015-01-01

    Full Text Available The formation of carbon nanotubes (CNTs, spherical carbon nanocapsules (CNCs, and carbon spheres (CSs is accomplished by using the method of reactions under autogenic pressure at elevated temperatures (RAPET. A powder mixture of naphthalene and nickel acetate tetrahydrate is dissociated under its autogenic pressure. The resultant CNTs and CNCs exhibit good graphitic quality, and the diameters range from 50~200 nm. Smooth and monodisperse CSs with the diameter ranging from 5~10 μm can be obtained by pyrolysis of pure naphthalene. Our results show that the reaction temperature and catalyst proportion play a key role in the formation of carbon nanostructures with RAPET method.

  3. Sclerotial formation of Polyporus umbellatus by low temperature treatment under artificial conditions.

    Science.gov (United States)

    Xing, Yong-Mei; Zhang, Li-Chun; Liang, Han-Qiao; Lv, Jing; Song, Chao; Guo, Shun-Xing; Wang, Chun-Lan; Lee, Tae-Soo; Lee, Min-Woong

    2013-01-01

    and inhibited sclerotial formation. Our findings may help to provide new insights into the biological mechanisms underlying sclerotial morphogenesis in P. umbellatus.

  4. Formation of amorphous carbon during microcrystalline graphite melting under the action of laser picosecond pulses

    International Nuclear Information System (INIS)

    Agranat, M.B.; Ashitkov, S.I.; Kirillin, A.V.; Kostanovskij, A.V.; Fortov, V.E.; Anisimov, S.I.; Kondratenko, P.S.

    1997-01-01

    Formation of a liquid phase with a transition to a homogeneous amorphous state under the surface layer solidification is detected under picosecond laser pulse effect on the microcrystalline graphite. A periodic surface structure is produced in the heating region with the period of the order of the length of the heating pulse wave, its strokes following the direction of this pulse polarization. Study of the probing laser pulse reflection kinetics has shown, that the typical time of liquid phase and solidification life makes up ∼ 10 -10 s

  5. Crack formation of steel reinforced concrete structure under stress in construction period

    Directory of Open Access Journals (Sweden)

    Hua Zhu

    2016-03-01

    Full Text Available To obtain deformation rules of steel reinforced concrete structure under stress, this study explored the crack formation in construction period. A novel structure system – steel reinforced concrete structure with shear wall and truss at the bottom was analyzed using on-the-spot test in combination with theoretical simulation analysis with SAP2000 software. It was found that, factors influencing crack formation of steel reinforced concrete structure in construction period included construction load, creep of concrete, shrinkage of concrete, displacement of bond of section steel and concrete as well as leveling. In the construction period, the simulated results and the measured results were highly fitted under the influence of time-variant characteristics such as compressive strength, elasticity modulus, creep and shrinkage. Through processing and analyzing the measured data, we obtained the development rules of crack formation of steel reinforced concrete structure with different strength grades as well as deformation rules of time-varying structure system in construction period, figured out the reason for the difference between the simulated results and the measured results, analyzed the deformation of structural components under stress in construction period and proposed some suggestions. This work is beneficial to ensure safe and high-efficient operation of construction

  6. Resolving the clinico-radiological paradox in multiple sclerosis

    Science.gov (United States)

    Chard, Declan; Trip, S Anand

    2017-01-01

    Understanding the clinico-radiological paradox is important in the search for more sensitive and specific surrogates of relapses and disability progression (such that they can be used to inform treatment choices in individual people with multiple sclerosis) and to gain a better understanding of the pathophysiological basis of disability in multiple sclerosis (to identify and assess key therapeutic targets). In this brief review, we will consider themes and issues underlying the clinico-radiological paradox and recent advances in its resolution. PMID:29093810

  7. Mechanical Paradox: The Uphill Roller

    Science.gov (United States)

    Cortes, Emilio; Cortes-Poza, D.

    2011-01-01

    We analyse in detail the dynamics of a mechanical system which is a rigid body with the geometry of a double cone. This double cone is apparently able to spontaneously roll uphill along inclined rails. The experiment has been known for some centuries, and because of its peculiar behaviour, it has been named "mechanical paradox". Although this…

  8. The Banach-Tarski paradox

    CERN Document Server

    Wagon, Stan

    1985-01-01

    The Banach-Tarski paradox is a most striking mathematical construction: it asserts that a solid ball may be taken apart into finitely many pieces that can be rearranged using rigid motions to form a ball twice as large as the original. This volume explore

  9. Teaching Quantum Physics without Paradoxes

    Science.gov (United States)

    Hobson, Art

    2007-01-01

    Although the resolution to the wave-particle paradox has been known for 80 years, it is seldom presented. Briefly, the resolution is that material particles and photons are the quanta of extended spatially continuous but energetically quantized fields. But because the resolution resides in quantum field theory and is not usually spelled out in…

  10. Spontaneous formation of non-uniform double helices for elastic rods under torsion

    International Nuclear Information System (INIS)

    Li, Hongyuan; Zhao, Shumin; Xia, Minggang; He, Siyu; Yang, Qifan; Yan, Yuming; Zhao, Hanqiao

    2017-01-01

    The spontaneous formation of double helices for filaments under torsion is common and significant. For example, the research on the supercoiling of DNA is helpful for understanding the replication and transcription of DNA. Similar double helices can appear in carbon nanotube yarns, cables, telephone wires and so forth. We noticed that non-uniform double helices can be produced due to the surface friction induced by the self-contact. Therefore an ideal model was presented to investigate the formation of double helices for elastic rods under torque. A general equilibrium condition which is valid for both the smooth surface and the rough surface situations is derived by using the variational method. By adding further constraints, the smooth and rough surface situations are investigated in detail respectively. Additionally, the model showed that the specific process of how to twist and slack the rod can determine the surface friction and hence influence the configuration of the double helix formed by rods with rough surfaces. Based on this principle, a method of manufacturing double helices with designed configurations was proposed and demonstrated. Finally, experiments were performed to verify the model and the results agreed well with the theory. - Highlights: • An ideal model is conceived to investigate the spontaneous formation of double helices for rods under torsion. • Variational method is used to obtain a universal result for the double helix formation process • Self-contact and surface friction is considered to analyze the non-uniform double helix. • A novel method of producing double helix with arbitrary configuration is proposed and demonstrated. • The experiment results agree well with the theory.

  11. Spontaneous formation of non-uniform double helices for elastic rods under torsion

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hongyuan [Department of Applied Physics, School of Science, Xi' an Jiaotong University, Shaanxi 710049 (China); Zhao, Shumin, E-mail: zhaosm@mail.xjtu.edu.cn [Department of Applied Physics, School of Science, Xi' an Jiaotong University, Shaanxi 710049 (China); Xia, Minggang [Department of Optical Information Science and Technology, School of Science, Xi' an Jiaotong University, 710049 (China); Laboratory of Nanostructure and Physics Properties, School of Science, Xi' an Jiaotong University, 710049 (China); He, Siyu [Department of Applied Physics, School of Science, Xi' an Jiaotong University, Shaanxi 710049 (China); Yang, Qifan [Department of Biomedical Engineering, School of Life Science and Technology, Xi' an Jiaotong University, Shaanxi 710049 (China); Yan, Yuming [Department of Electrical Engineering and Automation, School of Electrical Engineering, Xi' an Jiaotong University, Shaanxi 710049 (China); Zhao, Hanqiao [Department of Biomedical Engineering, School of Life Science and Technology, Xi' an Jiaotong University, Shaanxi 710049 (China)

    2017-02-19

    The spontaneous formation of double helices for filaments under torsion is common and significant. For example, the research on the supercoiling of DNA is helpful for understanding the replication and transcription of DNA. Similar double helices can appear in carbon nanotube yarns, cables, telephone wires and so forth. We noticed that non-uniform double helices can be produced due to the surface friction induced by the self-contact. Therefore an ideal model was presented to investigate the formation of double helices for elastic rods under torque. A general equilibrium condition which is valid for both the smooth surface and the rough surface situations is derived by using the variational method. By adding further constraints, the smooth and rough surface situations are investigated in detail respectively. Additionally, the model showed that the specific process of how to twist and slack the rod can determine the surface friction and hence influence the configuration of the double helix formed by rods with rough surfaces. Based on this principle, a method of manufacturing double helices with designed configurations was proposed and demonstrated. Finally, experiments were performed to verify the model and the results agreed well with the theory. - Highlights: • An ideal model is conceived to investigate the spontaneous formation of double helices for rods under torsion. • Variational method is used to obtain a universal result for the double helix formation process • Self-contact and surface friction is considered to analyze the non-uniform double helix. • A novel method of producing double helix with arbitrary configuration is proposed and demonstrated. • The experiment results agree well with the theory.

  12. Influences of surface hydrophilicity on frost formation on a vertical cold plate under natural convection conditions

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhongliang; Zhang, Xinghua; Wang, Hongyan; Meng, Sheng; Cheng, Shuiyuan [Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Ministry of Education and Key Laboratory of Heat Transfer and Energy Conversion, Beijing Education Commission, College of Environmental and Energy Engineering, Beijing University of Technology, Pingleyuan 100, Beijing 100022 (China)

    2007-07-15

    Surface hydrophilicity has a strong influence on frost nucleation according to phase transition theory. To study this effect, a close observation of frost formation and deposition processes on a vertical plate was made under free convection conditions. The formation and shape variation of frost crystals during the initial period are described and the frost thickness variation with time on both hydrophobic and plain copper cold surfaces are presented. The various influencing factors are discussed in depth. The mechanism of surface hydrophilicity influence on frost formation was analyzed theoretically. This revealed that increasing the contact angle can increase the potential barrier and restrain crystal nucleation and growth and thus frost deposition. The experimental results show that the initial water drops formed on a hydrophobic surface are smaller and remain in the liquid state for a longer time compared with ones formed on a plain copper surface. It is also observed that the frost layer deposited on a hydrophobic surface is loose and weak. Though the hydrophobic surface can retard frost formation to a certain extent and causes a looser frost layer, our experimental results show that it does not depress the growth of the frost layer. (author)

  13. Photoinduced fibrils formation of chicken egg white lysozyme under native conditions.

    Science.gov (United States)

    Xie, Jin-Bing; Cao, Yi; Pan, Hai; Qin, Meng; Yan, Zhi-Qiang; Xiong, Xiang; Wang, Wei

    2012-11-01

    Recent findings showed that transiently accessing structurally native-like yet energetically higher conformational states is sufficient to trigger the formation of protein fibrils. Typically, these conformational states are made available through changing solvent conditions or introducing mutations. Here we show a novel way to initialize fibril formation for Chicken egg white lysozyme (CEWL) under native conditions via controlled UV illumination. Through a cassette of tryptophan-based photochemistry, the two terminal disulfide bonds in CEWL can be selectively reduced. The reduced CEWL is then converted to conformational states with the C-terminal fragment floppy upon thermal fluctuation. These states serve as precursors for the fibrillar aggregation. Intriguingly, the CEWL fibrils are stabilized by intermolecular disulfide bonds instead of noncovalent β-sheet structures, distinct from the amyloid-like lysozyme fibrils reported before. Based on the experimental evidences and all-atom molecular dynamics simulation, we proposed a "runaway domain-swapping" model for the structure of the CEWL fibrils, in which each CEWL molecule swaps the C-terminal fragment into the complementary position of the adjacent molecule along the fibrils. We anticipate that this fibrillation mechanism can be extended to many other disulfide-containing proteins. Our study stands for the first example of formation of protein fibrils under native conditions upon UV illumination and poses the potential danger of low UV dose to organisms at the protein level. Copyright © 2012 Wiley Periodicals, Inc.

  14. Formation of nitric oxide under action of UV and visible light on S-nitrosocompounds

    Science.gov (United States)

    Stepuro, Ivan I.; Adamchuk, Raisa I.; Anufrik, Slavomir S.; Stepuro, Vitali I.; Maskevich, Sergei A.

    2000-06-01

    It has been shown that NO is released under the exposure of the aqueous solutions of S-nitrosocompounds as well as blood plasma proteins and whole blood of healthy donors to UV and visible light. The NO release from degrading S- nitrosocompounds was monitored both spectrophotometrically (by nitrosohemoglobin formation) and using the quenching of pyrene fluorescence by nitric oxide. In addition to NO, thyil radicals which dismutate to disulfides, were formed under anaerobic conditions. In the presence of oxygen, peroxide compounds, cysteine acid derivatives and S-nitrocompounds are formed apart from disulfides, and NO is mainly converted to NO2-. It is suggested that NO releasing under the actin of UV and visible light from physiological depots induces vascular relaxation, which enhances the blood flow.

  15. Single- and multi-pulse formation of surface structures under static femtosecond irradiation

    Science.gov (United States)

    Guillermin, M.; Garrelie, F.; Sanner, N.; Audouard, E.; Soder, H.

    2007-07-01

    Femtosecond surface structure modifications are investigated under irradiation with laser pulses of 150 fs at 800 nm, on copper and silicon. We report sub-wavelength periodic structures formation (ripples) with a periodicity of 500 nm for both materials. These ripples are perpendicular to the laser polarization and can be obtained with only one pulse. The formation of these ripples corresponds to a fluence threshold of 1 J/cm 2 for copper and 0.15 J/cm 2 for silicon. We find several morphologies when more pulses are applied: larger ripples parallel to the polarization are formed with a periodicity of 1 μm and degenerate into a worm-like morphology with a higher number of pulses. In addition, walls of deep holes also show sub-wavelength and large ripples.

  16. Type IIA photosensitivity and formation of pores in optical fibers under intense ultraviolet irradiation

    International Nuclear Information System (INIS)

    Kukushkin, S. A.; Shlyagin, M. G.; Swart, P. L.; Chtcherbakov, A. A.; Osipov, A. V.

    2007-01-01

    Formation of the type IIA Bragg gratings in germanosilicate optical fibers is studied. We report the observation of such a type of gratings in the standard single-mode fiber (Corning SMF-28) under different experimental conditions. A mechanism for the type IIA photosensitivity in optical fibers is proposed which is based on nucleation and evolution of pores from vacancy-type defects in fiber areas where a high level of mechanical stress is induced under intense ultraviolet (UV) light. Evolution of fiber core temperature under influence of a single 20 ns light pulse from a KrF excimer laser was measured and compared with theoretical calculations. It was shown that transient thermoinduced stress in the fiber core can achieve a level sufficient for effective nucleation of pores. A theory describing formation of pores in optical fibers has been developed and was used to estimate the pore nucleation rate, concentration, and other parameters of pore evolution for different levels of UV fluence and fiber core stress

  17. Seismicity of the Paradox Basin and the Colorado Plateau interior

    International Nuclear Information System (INIS)

    Wong, I.G.

    1984-04-01

    National Waste Terminal Storage Program site qualification criteria require that a nuclear waste repository be located so that ground motion associated with the maximum credible and maximum probable earthquakes or other earthquake-associated effects will not have an unacceptable adverse impact on system performance. To determine whether a potential repository site located in the Paradox salt formation in the Paradox Basin of southeastern Utah satisfies these criteria, seismological studies were undertaken by Woodward-Clyde Consultants (WCC) in March 1978. These studies included: (1) analysis of historical seismicity; (2) analysis of contemporary seismicity and tectonics of both the Paradox Basin and surrounding Colorado Plateau, including an extensive program of microearthquake monitoring; (3) evaluation of the Paradox Basin crustal structure; (4) evaluation of mining-induced seismicity; and (5) characterization of design-related earthquake-induced ground motions pertinent to a potential repository site through studies of attentation and subsurface ground motions. A detailed discussion of the results of the seismological studies performed through December 1980 is contained in WCC (1982). The purpose of this topical report is to update and summarize the studies on the local, regional, and mining-induced seismicity conducted through December 1982. The limitations of any interpretations are also discussed and additional information that remains to be acquired is identified. 56 references, 45 figures, 4 tables

  18. The role of stable α-synuclein oligomers in the molecular events underlying amyloid formation

    DEFF Research Database (Denmark)

    Lorenzen, Nikolai; Nielsen, Søren Bang; Buell, Alexander K.

    2014-01-01

    α-synuclein (αSN), whose aggregation is strongly implicated in the development of Parkinson’s disease (PD). The two types of oligomers are both formed under conditions where amyloid fibril formation is observed but differ in molecular weight by an order of magnitude. Both possess a degree of β......, either as precursors of fibrils or as species involved in the fibril elongation process or instead if they are associated with an aggregation process that is distinct from that generating mature fibrils. Here we describe and characterize in detail two well-defined oligomeric species formed by the protein...

  19. Geologic characterization report for the Paradox Basin Study Region, Utah Study Areas. Volume 6. Salt Valley

    International Nuclear Information System (INIS)

    1984-12-01

    Surface landforms in the Salt Valley Area are generally a function of the Salt Valley anticline and are characterized by parallel and subparallel cuestaform ridges and hogbacks and flat valley floors. The most prominent structure in the Area is the Salt Valley anticline. Erosion resulting from the Tertiary uplift of the Colorado Plateau led to salt dissolution and subsequent collapse along the crest of the anticline. Continued erosion removed the collapse material, forming an axial valley along the crest of the anticline. Paleozoic rocks beneath the salt bearing Paradox Formation consist of limestone, dolomite, sandstone, siltstone and shale. The salt beds of the Paradox Formation occur in distinct cycles separated by an interbed sequence of anhydrite, carbonate, and clastic rocks. The Paradox Formation is overlain by Pennsylvanian limestone; Permian sandstone; and Mesozoic sandstone, mudstone, conglomerate and shale. No earthquakes have been reported in the Area during the period of the historic record and contemporary seismicity appears to be diffusely distributed, of low level and small magnitude. The upper unit includes the Permian strata and upper Honaker Trail Formation. The current data base is insufficient to estimate ground-water flow rates and directions in this unit. The middle unit includes the evaporites in the Paradox Formation and no laterally extensive flow systems are apparent. The lower unit consists of the rocks below the Paradox Formation where permeabilities vary widely, and the apparent flow direction is toward the west. 108 refs., 39 figs., 9 tabs

  20. Brown Backstops versus the Green Paradox (Replaced by CentER DP 2011-110)

    NARCIS (Netherlands)

    Michielsen, T.O.

    2011-01-01

    Imperfect climate policies may be ineffective when fossil fuel owners respond by shifting their supply spatially (coined carbon leakage) or intertemporally (the green paradox). Though these effects are usually analyzed separately, the underlying mechanisms are similar. Exhaustibleffossil fuel owners

  1. Nonequilibrium self-organization in alloys under irradiation leading to the formation of nano composites

    CERN Document Server

    Enrique, R A; Averback, R S; Bellon, P

    2003-01-01

    Alloys under irradiation are continuously driven away from equilibrium: Every time an external particle interacts with the atoms in the solid, a perturbation very localized in space and time is produced. Under this external forcing, phase and microstructural evolution depends ultimately on the dynamical interaction between the external perturbation and the internal recovery kinetics of the alloy. We consider the nonequilibrium steady state of an immiscible binary alloy subject to mixing by heavy-ion irradiation. It has been found that the range of the forced atomic relocations taking place during collision cascades plays an important role on the final microstructure: when this range is large enough, it can lead to the spontaneous formation of compositional patterns at the nanometer scale. These results were rationalized in the framework of a continuum model solved by deriving a nonequilibrium thermodynamic potential. Here we derive the nonequilibrium structure factor by including the role of fluctuations. In ...

  2. Coarsening and pattern formation during true morphological phase separation in unstable thin films under gravity

    Science.gov (United States)

    Kumar, Avanish; Narayanam, Chaitanya; Khanna, Rajesh; Puri, Sanjay

    2017-12-01

    We address in detail the problem of true morphological phase separation (MPS) in three-dimensional or (2 +1 )-dimensional unstable thin liquid films (>100 nm) under the influence of gravity. The free-energy functionals of these films are asymmetric and show two points of common tangency, which facilitates the formation of two equilibrium phases. Three distinct patterns formed by relative preponderance of these phases are clearly identified in "true MPS". Asymmetricity induces two different pathways of pattern formation, viz., defect and direct pathway for true MPS. The pattern formation and phase-ordering dynamics have been studied using statistical measures such as structure factor, correlation function, and growth laws. In the late stage of coarsening, the system reaches into a scaling regime for both pathways, and the characteristic domain size follows the Lifshitz-Slyozov growth law [L (t ) ˜t1 /3] . However, for the defect pathway, there is a crossover of domain growth behavior from L (t ) ˜t1 /4→t1 /3 in the dynamical scaling regime. We also underline the analogies and differences behind the mechanisms of MPS and true MPS in thin liquid films and generic spinodal phase separation in binary mixtures.

  3. Microbial mediated formation of Fe-carbonate minerals under extreme acidic conditions.

    Science.gov (United States)

    Sánchez-Román, Mónica; Fernández-Remolar, David; Amils, Ricardo; Sánchez-Navas, Antonio; Schmid, Thomas; San Martin-Uriz, Patxi; Rodríguez, Nuria; McKenzie, Judith A; Vasconcelos, Crisogono

    2014-04-23

    Discovery of Fe-carbonate precipitation in Rio Tinto, a shallow river with very acidic waters, situated in Huelva, South-western Spain, adds a new dimension to our understanding of carbonate formation. Sediment samples from this low-pH system indicate that carbonates are formed in physico-chemical conditions ranging from acid to neutral pH. Evidence for microbial mediation is observed in secondary electron images (Fig. 1), which reveal rod-shaped bacteria embedded in the surface of siderite nanocrystals. The formation of carbonates in Rio Tinto is related to the microbial reduction of ferric iron coupled to the oxidation of organic compounds. Herein, we demonstrate for the first time, that Acidiphilium sp. PM, an iron-reducing bacterium isolated from Rio Tinto, mediates the precipitation of siderite (FeCO3) under acidic conditions and at a low temperature (30°C). We describe nucleation of siderite on nanoglobules in intimate association with the bacteria cell surface. This study has major implications for understanding carbonate formation on the ancient Earth or extraterrestrial planets.

  4. A model of social network formation under the impact of structural balance

    Science.gov (United States)

    Li, Pei; Cheng, Jiajun; Chen, Yingwen; Wang, Hui

    2016-03-01

    Social networks have attracted remarkable attention from both academic and industrial societies and it is of great importance to understand the formation of social networks. However, most existing research cannot be applied directly to investigate social networks, where relationships are heterogeneous and structural balance is a common phenomenon. In this paper, we take both positive and negative relationships into consideration and propose a model to characterize the process of social network formation under the impact of structural balance. In this model, a new node first establishes a link with an existing node and then tries to connect to each of the newly connected node’s neighbors. If a new link is established, the type of this link is determined by structural balance. Then we analyze the degree distribution of the generated network theoretically, and estimate the fractions of positive and negative links. All analysis results are verified by simulations. These results are of importance to understand the formation of social networks, and the model can be easily extended to consider more realistic situations.

  5. Estenose Aórtica Paradoxal

    OpenAIRE

    Andreia Filipa Oliveira Campinas

    2017-01-01

    Trabalho final de mestrado integrado em Medicina (Cardiologia), apresentado à Faculdade de Medicina da Universidade de Coimbra. A estenose aórtica paradoxal define-se por uma área valvular aórtica ≤ 1 cm2, um volume sistólico indexado 50%). Caracteriza-se por uma marcada remodelagem concêntrica do ventrículo esquerdo, com predomínio de disfunção diastólic...

  6. Reinterpretaion of the friendship paradox

    Science.gov (United States)

    Fu, Jingcheng; Wu, Jianliang

    The friendship paradox (FP) is a sociological phenomenon stating that most people have fewer friends than their friends do. It is to say that in a social network, the number of friends that most individuals have is smaller than the average number of friends of friends. This has been verified by Feld. We call this interpreting method mean value version. But is it the best choice to portray the paradox? In this paper, we propose a probability method to reinterpret this paradox, and we illustrate that the explanation using our method is more persuasive. An individual satisfies the FP if his (her) randomly chosen friend has more friends than him (her) with probability not less than 1/2. Comparing the ratios of nodes satisfying the FP in networks, rp, we can see that the probability version is stronger than the mean value version in real networks both online and offline. We also show some results about the effects of several parameters on rp in random network models. Most importantly, rp is a quadratic polynomial of the power law exponent γ in Price model, and rp is higher when the average clustering coefficient is between 0.4 and 0.5 in Petter-Beom (PB) model. The introduction of the probability method to FP can shed light on understanding the network structure in complex networks especially in social networks.

  7. Clay mineral formation under oxidized conditions and implications for paleoenvironments and organic preservation on Mars

    Energy Technology Data Exchange (ETDEWEB)

    Gainey, Seth R.; Hausrath, Elisabeth M.; Adcock, Christopher T.; Tschauner, Oliver; Hurowitz, Joel A.; Ehlmann, Bethany L.; Xiao, Yuming; Bartlett, Courtney L. (CIW); (UNLV); (CIT); (SBU)

    2017-11-01

    Clay mineral-bearing locations have been targeted for martian exploration as potentially habitable environments and as possible repositories for the preservation of organic matter. Although organic matter has been detected at Gale Crater, Mars, its concentrations are lower than expected from meteoritic and indigenous igneous and hydrothermal reduced carbon. We conducted synthesis experiments motivated by the hypothesis that some clay mineral formation may have occurred under oxidized conditions conducive to the destruction of organics. Previous work has suggested that anoxic and/or reducing conditions are needed to synthesize the Fe-rich clay mineral nontronite at low temperatures. In contrast, our experiments demonstrated the rapid formation of Fe-rich clay minerals of variable crystallinity from aqueous Fe3+ with small amounts of aqueous Mg2+. Our results suggest that Fe-rich clay minerals such as nontronite can form rapidly under oxidized conditions, which could help explain low concentrations of organics within some smectite-containing rocks or sediments on Mars.

  8. Neural mechanisms underlying migrating motor complex formation in mouse isolated colon

    Science.gov (United States)

    Brierley, Stuart M; Nichols, Kim; Grasby, Dallas J; Waterman, Sally A

    2001-01-01

    Little is known about the intrinsic enteric reflex pathways associated with migrating motor complex (MMC) formation. Acetylcholine (ACh) mediates the rapid component of the MMC, however a non-cholinergic component also exists. The present study investigated the possible role of endogenous tachykinins (TKs) in the formation of colonic MMCs and the relative roles of excitatory and inhibitory pathways.MMCs were recorded from the circular muscle at four sites (proximal, proximal-mid, mid-distal and distal) along the mouse colon using force transducers.The tachykinin (NK1 and NK2) receptor antagonists SR-140 333 (250 nM) and SR-48 968 (250 nM) reduced the amplitude of MMCs at all recording sites, preferentially abolishing the long duration contraction. Residual MMCs were abolished by the subsequent addition of atropine (1 μM).The neuronal nitric oxide synthase inhibitor, Nωnitro-L-arginine (L-NOARG, 100 μM), increased MMC amplitude in the distal region, whilst reducing the amplitude in the proximal region. In preparations where MMCs did not migrate to the distal colon, addition of L-NOARG resulted in the formation of MMCs. Subsequent addition of apamin (250 nM) or suramin (100 μM) further increased MMC amplitude in the distal region, whilst suramin increased MMC amplitude in the mid-distal region. Apamin but not suramin reduced MMC amplitude in the proximal region. Subsequent addition of SR-140 333 and SR-48 968 reduced MMC amplitude at all sites. Residual MMCs were abolished by atropine (1 μM).In conclusion, TKs, ACh, nitric oxide (NO) and ATP are involved in the neural mechanisms underlying the formation of MMCs in the mouse colon. Tachykinins mediate the long duration component of the MMC via NK1 and NK2 receptors. Inhibitory pathways may be involved in determining whether MMCs are formed. PMID:11159701

  9. Humic acid-induced silver nanoparticle formation under environmentally relevant conditions.

    Science.gov (United States)

    Akaighe, Nelson; Maccuspie, Robert I; Navarro, Divina A; Aga, Diana S; Banerjee, Sarbajit; Sohn, Mary; Sharma, Virender K

    2011-05-01

    The formation of silver nanoparticles (AgNPs) via reduction of silver ions (Ag(+)) in the presence of humic acids (HAs) under various environmentally relevant conditions is described. HAs tested originated from the Suwannee River (SUW), and included samples of three sedimentary HAs (SHAs), and five soils obtained across the state of Florida. The time required to form AgNPs varied depending upon the type and concentration of HA, as well as temperature. SUW and all three SHAs reduced Ag(+) at 22 °C. However, none of the soil HAs formed absorbance-detectable AgNPs at room temperature when allowed to react for a period of 25 days, at which time experiments were halted. The appearance of the characteristic surface plasmon resonance (SPR) of AgNPs was observed by ultraviolet-visible spectroscopy in as few as 2-4 days at 22 °C for SHAs and SUW. An elevated temperature of 90 °C resulted in the accelerated appearance of the SPR within 90 min for SUW and all SHAs. The formation of AgNPs at 90 °C was usually complete within 3 h. Transmission electron microscopy and atomic force microscopy images showed that the AgNPs formed were typically spherical and had a broad size distribution. Dynamic light scattering also revealed polydisperse particle size distributions. HAs appeared to colloidally stabilize AgNPs based on lack of any significant change in the spectral characteristics over a period of two months. The results suggest the potential for direct formation of AgNPs under environmental conditions from Ag(+) sources, implying that not all AgNPs observed in natural waters today may be of anthropogenic origin.

  10. Corrosion Behavior and Oxide Film Formation of T91 Steel under Different Water Chemistry Operation Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, D. Q.; Shi, C.; Li, J.; Gao, L. X. [Shanghai University of Electric Power, Shanghai (China); Lee, K. Y. [Dalian University of Technology, Dalian (China)

    2017-02-15

    The corrosion behavior of a ferritic/martensitic steel T91 exposed to an aqueous solution containing chloride and sulfate ions is investigated depending on the stimulated all-volatile treatment (AVT) and under oxygenated treatment (OT) conditions. The corrosion of T91 steel under OT condition is severe, while the corrosion under AVT condition is not. The co-existence of chloride and sulfate ions has antagonistic effect on the corrosion of T91 steel in both AVT and OT conditions. Unlike to corrosion resistance in the aqueous solution, OT pretreatment provides T91 steel lower oxidation-resistance than VAT pretreatment. From scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) and X-ray diffraction (XRD) analysis, the lower corrosion resistance in the aqueous solution by VAT conditions possibly is due to the formation of pits. In addition, the lower oxidation resistance of T91 steel pretreated by OT conditions is explained as follows: the cracks formed during the immersion under OT conditions accelerated peeling-off rate of the oxide film.

  11. Paradoxical Leadership to Enable Strategic Agility

    OpenAIRE

    Lewis, M. W.; Andriopoulos, C.; Smith, W. K.

    2014-01-01

    Strategic agility evokes contradictions, such as stability-flexibility, commitment-change, and established routines-novel approaches. These competing demands pose challenges that require paradoxical leadership—practices seeking creative, both/and solutions that can enable fast-paced, adaptable decision making. Why is managing paradox critical to strategic agility? And which practices enable leaders to effectively manage tensions? This article describes the paradoxical nature of strategic agil...

  12. A flow cell for in situ synchrotron x-ray diffraction studies of scale formation under Bayer processing conditions

    Science.gov (United States)

    Webster, Nathan A. S.; Madsen, Ian C.; Loan, Melissa J.; Scarlett, Nicola V. Y.; Wallwork, Kia S.

    2009-08-01

    The design, construction, and commissioning of a stainless steel flow cell for in situ synchrotron x-ray diffraction studies of scale formation under Bayer processing conditions is described. The use of the cell is demonstrated by a study of Al(OH)3 scale formation on a mild steel substrate from synthetic Bayer liquor at 70 °C. The cell design allows for interchangeable parts and substrates and would be suitable for the study of scale formation in other industrial processes.

  13. Paradoxes in carcinogenesis: New opportunities for research directions

    Directory of Open Access Journals (Sweden)

    Kramer Barnett S

    2007-08-01

    Full Text Available Abstract Background The prevailing paradigm in cancer research is the somatic mutation theory that posits that cancer begins with a single mutation in a somatic cell followed by successive mutations. Much cancer research involves refining the somatic mutation theory with an ever increasing catalog of genetic changes. The problem is that such research may miss paradoxical aspects of carcinogenesis for which there is no likely explanation under the somatic mutation theory. These paradoxical aspects offer opportunities for new research directions that should not be ignored. Discussion Various paradoxes related to the somatic mutation theory of carcinogenesis are discussed: (1 the presence of large numbers of spatially distinct precancerous lesions at the onset of promotion, (2 the large number of genetic instabilities found in hyperplastic polyps not considered cancer, (3 spontaneous regression, (4 higher incidence of cancer in patients with xeroderma pigmentosa but not in patients with other comparable defects in DNA repair, (5 lower incidence of many cancers except leukemia and testicular cancer in patients with Down's syndrome, (6 cancer developing after normal tissue is transplanted to other parts of the body or next to stroma previously exposed to carcinogens, (7 the lack of tumors when epithelial cells exposed to a carcinogen were transplanted next to normal stroma, (8 the development of cancers when Millipore filters of various pore sizes were was inserted under the skin of rats, but only if the holes were sufficiently small. For the latter paradox, a microarray experiment is proposed to try to better understand the phenomena. Summary The famous physicist Niels Bohr said "How wonderful that we have met with a paradox. Now we have some hope of making progress." The same viewpoint should apply to cancer research. It is easy to ignore this piece of wisdom about the means to advance knowledge, but we do so at our peril.

  14. The St. Petersburg paradox: An experimental solution

    Science.gov (United States)

    Da Silva, Sergio; Matsushita, Raul

    2016-03-01

    The St. Petersburg paradox refers to a gamble of infinite expected value, where people are likely to spend only a small entrance fee for it. There is a huge volume of literature that mostly concentrates on the psychophysics of the game; experiments are scant. Here, rather than focusing on the psychophysics, we offer an experimental, "physical" solution as if robots played the game. After examining the time series formed by one billion plays, we: confirm that there is no characteristic scale for this game; explicitly formulate the implied power law; and identify the type of α-stable distribution associated with the game. We find an α = 1 and, thus, the underlying distribution of the game is a Cauchy flight, as hinted by Paul Samuelson.

  15. Healthcare leadership's diversity paradox.

    Science.gov (United States)

    Silver, Reginald

    2017-02-06

    Purpose The purpose of this research study was to obtain healthcare executives' perspectives on diversity in executive healthcare leadership. The study focused on identifying perspectives about diversity and its potential impact on the access of healthcare services by people of color. The study also identified perspectives about factors that influence the attainment of executive healthcare roles by people of color. Design/methodology/approach A convenience sample of healthcare executives was obtained. The executives identified themselves as belonging to one of two subgroups, White healthcare executives or executives of color. Participants were interviewed telephonically in a semi-structured format. The interviews were transcribed and entered into a qualitative software application. The data were codified and important themes were identified. Findings The majority of the study participants perceive that diversity of the executive healthcare leadership team is important. There were differences in perspective among the subgroups as it relates to solutions to improve access to healthcare by people of color. There were also differences in perspective among the subgroups, as it relates to explaining the underrepresentation of people of color in executive healthcare leadership roles. Research limitations/implications This research effort benefited from the subject matter expertise of 24 healthcare executives from two states. Expansion of the number of survey participants and broadening the geographical spread of where participants were located may have yielded more convergence and/or more divergence in perspectives about key topics. Practical implications The findings from this research study serve to add to the existing body of literature on diversity in executive healthcare leadership. The findings expand on the importance of key elements in contemporary literature such as diversity, cultural competency and perspectives about the need for representation of people of

  16. The three-box paradox revisited

    International Nuclear Information System (INIS)

    Ravon, Tamar; Vaidman, Lev

    2007-01-01

    The classical three-box paradox of Kirkpatrick (2003 J. Phys. A: Math. Gen. 36 4891) is compared to the original quantum three-box paradox of Aharonov and Vaidman (1991 J. Phys. A: Math. Gen. 24 2315). It is argued that the quantum three-box experiment is a 'quantum paradox' in the sense that it is an example of a classical task which cannot be accomplished using classical means, but can be accomplished using quantum devices. It is shown that Kirkpatrick's card game is analogous to a different game with a particle in three boxes which does not contain paradoxical features

  17. Cerebral tuberculoma as a manifestation of paradoxical reaction in patients with pulmonary and extrapulmonary tuberculosis

    Directory of Open Access Journals (Sweden)

    Anirban Das

    2012-01-01

    Full Text Available Expansion of cerebral tuberculomas or their new appearance as a manifestation of paradoxical reaction in patients under antituberculous chemotherapy is well documented. Distinguishing paradoxical reaction from disease progression or treatment failure is an important issue in tuberculosis management. Five cases of cerebral tuberculomas are reported here as manifestations of paradoxical reaction in patients with pulmonary and extrapulmonary tuberculosis on antituberculous treatment. Case 1 and 2 had tuberculous meningitis, Case 3 had miliary tuberculosis, Case 4 had miliary tuberculosis and destructive vertebral lesions, and Case 5 had pulmonary tuberculosis. Continuation of antituberculous drugs and addition of steroids led to full recovery of all patients.

  18. The Paradox of Precaution

    International Nuclear Information System (INIS)

    Bechmann, Gotthard

    2009-12-01

    The precautionary principle cannot rid itself of risk. In the area of precaution it re-emerges as the risk of precaution. This is due to the fact that precaution is a disposition of the future which can only be decided in the medium of probability/lack of probability. With this type of calculation, we take advantage of the uncertainty of the future and at the same time our own uncertainty to make decisions in the present that can be confirmed or refuted by future states of the present. We will never reach the safe side since the future as future is inherently uncertain. If we take this realisation as a basis, we see that precaution does not mean creating a future free of risk or danger, but that the precautionary principle is a meta-rule how this basic uncertainty can be, and is, processed communicatively, i.e. at the societal level. On this topic a number of remarks: - There are no apodeictic judgements possible with respect to issues of the future, in particular when these are possible catastrophes. Whoever operates in such cases with true assertions disqualifies himself. As we know, this has ruined the political reputation of scientific experts. - We must further do without consensus on principles or on the priority of certain values. Negotiations on decisions must be formulated and understood in a way that they are compatible with a disagreement on principle. Current coordination is then more important than correspondence in the cognitive and evaluative foundations of the assessment of future. - Communication itself is better set up not as communicative action in the sense of Habermas, but on the contrary as strategic action under conditions of uncertainty, that is we have to stay aware that debates related to the future are social constructions and not true statements. - All in all, the demand for 'participation' should be downplayed in favour of strengthening the right to information in order to able to develop the largest possible number of constructs. - The

  19. The Paradox of Precaution

    Energy Technology Data Exchange (ETDEWEB)

    Bechmann, Gotthard [Forschungszentrum Karlsruhe Technik und Umwelt, Inst. fuer Technikfolgeabschaetzung und Systemanalyse (ITAS), Karlsruhe (Germany)], e-mail: bechmann@itas.fzk.de

    2009-12-15

    The precautionary principle cannot rid itself of risk. In the area of precaution it re-emerges as the risk of precaution. This is due to the fact that precaution is a disposition of the future which can only be decided in the medium of probability/lack of probability. With this type of calculation, we take advantage of the uncertainty of the future and at the same time our own uncertainty to make decisions in the present that can be confirmed or refuted by future states of the present. We will never reach the safe side since the future as future is inherently uncertain. If we take this realisation as a basis, we see that precaution does not mean creating a future free of risk or danger, but that the precautionary principle is a meta-rule how this basic uncertainty can be, and is, processed communicatively, i.e. at the societal level. On this topic a number of remarks: - There are no apodeictic judgements possible with respect to issues of the future, in particular when these are possible catastrophes. Whoever operates in such cases with true assertions disqualifies himself. As we know, this has ruined the political reputation of scientific experts. - We must further do without consensus on principles or on the priority of certain values. Negotiations on decisions must be formulated and understood in a way that they are compatible with a disagreement on principle. Current coordination is then more important than correspondence in the cognitive and evaluative foundations of the assessment of future. - Communication itself is better set up not as communicative action in the sense of Habermas, but on the contrary as strategic action under conditions of uncertainty, that is we have to stay aware that debates related to the future are social constructions and not true statements. - All in all, the demand for 'participation' should be downplayed in favour of strengthening the right to information in order to able to develop the largest possible number of

  20. The Paradox of Precaution

    Energy Technology Data Exchange (ETDEWEB)

    Bechmann, Gotthard (Forschungszentrum Karlsruhe Technik und Umwelt, Inst. fuer Technikfolgeabschaetzung und Systemanalyse (ITAS), Karlsruhe (Germany)), e-mail: bechmann@itas.fzk.de

    2009-12-15

    The precautionary principle cannot rid itself of risk. In the area of precaution it re-emerges as the risk of precaution. This is due to the fact that precaution is a disposition of the future which can only be decided in the medium of probability/lack of probability. With this type of calculation, we take advantage of the uncertainty of the future and at the same time our own uncertainty to make decisions in the present that can be confirmed or refuted by future states of the present. We will never reach the safe side since the future as future is inherently uncertain. If we take this realisation as a basis, we see that precaution does not mean creating a future free of risk or danger, but that the precautionary principle is a meta-rule how this basic uncertainty can be, and is, processed communicatively, i.e. at the societal level. On this topic a number of remarks: - There are no apodeictic judgements possible with respect to issues of the future, in particular when these are possible catastrophes. Whoever operates in such cases with true assertions disqualifies himself. As we know, this has ruined the political reputation of scientific experts. - We must further do without consensus on principles or on the priority of certain values. Negotiations on decisions must be formulated and understood in a way that they are compatible with a disagreement on principle. Current coordination is then more important than correspondence in the cognitive and evaluative foundations of the assessment of future. - Communication itself is better set up not as communicative action in the sense of Habermas, but on the contrary as strategic action under conditions of uncertainty, that is we have to stay aware that debates related to the future are social constructions and not true statements. - All in all, the demand for 'participation' should be downplayed in favour of strengthening the right to information in order to able to develop the largest possible number of

  1. Physio-chemical hydrodynamic mechanism underlying the formation of thin adsorbed boundary films.

    Science.gov (United States)

    Chong, W W F; Teodorescu, M; Rahnejat, H

    2012-01-01

    The formation of low shear strength surface-adhered thin films mitigates excessive friction in mixed or boundary regimes of lubrication. Tribo-films are formed as a consequence of molecular chemical reactions with the surfaces. The process is best viewed in the context of a lubricant-surface system. Therefore, it is usually surmised that the adsorption of lubricant molecular species to the contact surfaces is underlying to the formation of ultra-thin lubricant films. The paper considers contact between smooth surfaces at close separation. This may be regarded as the contact of a pair of asperity summits, whose dimensions, however small, are far larger than the size of fluid molecules within the conjunction. In such diminishing separations the constraining effect of relatively smooth solid barriers causes oscillatory solvation of fluid molecules. This effect accounts for the conjunctional load capacity but does not contribute to mitigating friction, except when molecular adsorption is taken into account with long chain molecules which tend to inhibit solvation. The paper presents an analytical predictive model based on the Ornstein-Zernike method with the Percus-Yevick approximation of a narrow interaction potential between conjunctional composition. The predictions confirm the above stated physical facts in a fundamental manner.

  2. Formation of ‘Crioula’ guava rootstock under saline water irrigation and nitrogen doses

    Directory of Open Access Journals (Sweden)

    Leandro de P. Souza

    Full Text Available ABSTRACT The objective of this research was to evaluate the growth and formation of fresh and dry weight of ‘Crioula’ guava rootstock irrigated with waters of different saline levels and nitrogen (N doses, in an experiment conducted in plastic tubes under greenhouse conditions. The experimental design was randomized blocks, in a 5 x 4 factorial scheme with four replicates, and the treatments consisted of five levels of water electrical conductivity - ECw (0.3, 1.1, 1.9, 2.7 and 3.5 dS m-1 and four N doses (70, 100, 130 and 160% of the N dose recommended for the cultivation of guava seedlings, cv. ‘Paluma’. The dose referring to 100% corresponds to 773 mg of N dm-3. The highest growth of ‘Crioula’ guava rootstock was obtained with ECw of 0.3 dS m-1 and fertilization of 541.1 mg N dm-3 of soil; increasing N doses did not reduce the deleterious effect of the salt stress on the growth and phytomass formation of ‘Crioula’ guava rootstock; irrigation with water of up to 1.75 dS m-1, in the production of guava rootstocks, promotes acceptable reduction of 10% in growth and quality of the seedlings.

  3. Field measurements of key parameters associated with nocturnal OBT formation in vegetables grown under Canadian conditions

    International Nuclear Information System (INIS)

    Kim, S.B.; Workman, W.G.; Korolevych, V.; Davis, P.A.

    2012-01-01

    The objective of this study was to provide the parameter values required to model OBT formation in the edible parts of plants following a hypothetical accidental tritium release to the atmosphere at night. The parameters considered were leaf area index, stomatal resistance, photosynthesis rate, the photosynthetic production rate of starch, the nocturnal hydrolysis rate of starch, the fraction of starch produced daily by photosynthesis that appears in the fruits, and the mass of the fruit. Values of these parameters were obtained in the summer of 2002 for lettuce, radishes and tomatoes grown under typical Canadian environmental conditions. Based on the maximum observed photosynthetic rate and growth rate, the fraction of starch translocated to the fruit was calculated to be 17% for tomato fruit and 14% for radish root. - Highlights: ► Plant physiological parameters affecting nocturnal OBT formation have been investigated. ► The fraction of starch produced daily by photosynthesis in the leaves that appears in the fruit was calculated. ► Realistic estimates of OBT concentrations following a nighttime accidental HTO release to the atmosphere.

  4. The formation of cubic ice under conditions relevant to Earth's atmosphere.

    Science.gov (United States)

    Murray, Benjamin J; Knopf, Daniel A; Bertram, Allan K

    2005-03-10

    An important mechanism for ice cloud formation in the Earth's atmosphere is homogeneous nucleation of ice in aqueous droplets, and this process is generally assumed to produce hexagonal ice. However, there are some reports that the metastable crystalline phase of ice, cubic ice, may form in the Earth's atmosphere. Here we present laboratory experiments demonstrating that cubic ice forms when micrometre-sized droplets of pure water and aqueous solutions freeze homogeneously at cooling rates approaching those found in the atmosphere. We find that the formation of cubic ice is dominant when droplets freeze at temperatures below 190 K, which is in the temperature range relevant for polar stratospheric clouds and clouds in the tropical tropopause region. These results, together with heat transfer calculations, suggest that cubic ice will form in the Earth's atmosphere. If there were a significant fraction of cubic ice in some cold clouds this could increase their water vapour pressure, and modify their microphysics and ice particle size distributions. Under specific conditions this may lead to enhanced dehydration of the tropopause region.

  5. Texture formation in orthorhombic alpha-uranium under simple compression and rolling to high strains

    Science.gov (United States)

    Zecevic, Miroslav; Knezevic, Marko; Beyerlein, Irene J.; McCabe, Rodney J.

    2016-05-01

    We study the mechanical response and texture evolution of alpha-uranium during simple compression and rolling at 573 K. In order to determine the underlying mechanisms governing plasticity and texture formation, we perform detailed characterizations using electron backscattered diffraction and constitutive modeling using a dislocation-density based hardening law within a visco-plastic self-consistent homogenization. We show that the model achieves good agreement with experimental measurements in terms of texture and stress-strain response. From detailed comparison of experimental and modeling results, we infer that in both through-thickness compression (TTC) and rolling at 573K, the active slip modes are floor slip (001)[100] and chimney slip 1 / 2 { 110 } with slightly different ratios. However, { 130 } twinning is not active in TTC compression but profuse during rolling. Further analysis indicates that during rolling, floor slip (001)[100] results in the formation of two pronounced (001) texture peaks tilted 10-15° away from the normal toward the rolling direction.

  6. Phase formation polycrystalline vanadium oxide via thermal annealing process under controlled nitrogen pressure

    Science.gov (United States)

    Jessadaluk, S.; Khemasiri, N.; Rahong, S.; Rangkasikorn, A.; Kayunkid, N.; Wirunchit, S.; Horprathum, M.; Chananonnawathron, C.; Klamchuen, A.; Nukeaw, J.

    2017-09-01

    This article provides an approach to improve and control crystal phases of the sputtering vanadium oxide (VxOy) thin films by post-thermal annealing process. Usually, as-deposited VxOy thin films at room temperature are amorphous phase: post-thermal annealing processes (400 °C, 2 hrs) under the various nitrogen (N2) pressures are applied to improve and control the crystal phase of VxOy thin films. The crystallinity of VxOy thin films changes from amorphous to α-V2O5 phase or V9O17 polycrystalline, which depend on the pressure of N2 carrier during annealing process. Moreover, the electrical resistivity of the VxOy thin films decrease from 105 Ω cm (amorphous) to 6×10-1 Ω cm (V9O17). Base on the results, our study show a simply method to improve and control phase formation of VxOy thin films.

  7. The mechanism for diamagnetic products formation under the radiolysis of alkali nitrates

    Energy Technology Data Exchange (ETDEWEB)

    Anan' ev, Vladimir [Department of Analytical Chemistry, Kemerovo State University, Krasnaya Street, 6, Kemerovo 650043 (Russian Federation)], E-mail: eprlab@kemsu.ru

    2009-06-15

    Based on optical measurements, the kinetics of peroxynitrite accumulation in alkali nitrate crystals {gamma}-irradiated at 310 K has been investigated. The initial radiation chemical yields were calculated to be 0.60{+-}0.05, 0.14{+-}0.03, 0.35{+-}0.03, 0.65{+-}0.04 (100 eV){sup -1} for NaNO{sub 3}, KNO{sub 3}, RbNO{sub 3}, and CsNO{sub 3}, respectively. The mechanism for the radiolysis of crystalline alkali nitrates is interpreted in terms of formation of the peroxynitrite ions and the nitrite ions from high-energy singlet and triplet excited states of the nitrate ions, respectively. These states can be generating under the radiationless transitions of electrons from the cation conductivity band into the anion conductivity band accompanied by the Auger excitation of the nitrate ions.

  8. Expression--An Experimental Field for Investigation and Management of the Paradox of Education (With Illustrations from Voice Education)

    Science.gov (United States)

    Nohavová, Alena; Slavík, Jan

    2012-01-01

    This article introduces and explains the concept of the "paradox of education" for capturing the polarity between autonomy and heteronomy in education. The paradox of education is an essential part of the curriculum and, if not under control, manifests itself in the discrepancy between the teaching process, its objectives and evaluation…

  9. A Note on Faraday Paradoxes

    CERN Document Server

    Auchmann, Bernhard; Russenschuck, Stephan

    2014-01-01

    The validity of the flux rule to determine the electromotive force in a cycle, epsilon = -d Phi/dt, has been the subject of a large amount of controversy since the beginning of electrical technology. Although most authors reach correct conclusions for a class of problems called Faraday paradoxes, the arguments that are used vary and often rely on ad-hoc physical reasoning. A didactic and insightful treatment should be based solely on Maxwell's equations, the constitutive laws, and a detailed study of the mathematics involved.

  10. Mechanism Underlying the Spatial Pattern Formation of Dominant Tree Species in a Natural Secondary Forest.

    Directory of Open Access Journals (Sweden)

    Guodong Jia

    Full Text Available Studying the spatial pattern of plant species may provide significant insights into processes and mechanisms that maintain stand stability. To better understand the dynamics of naturally regenerated secondary forests, univariate and bivariate Ripley's L(r functions were employed to evaluate intra-/interspecific relationships of four dominant tree species (Populus davidiana, Betula platyphylla, Larix gmelinii and Acer mono and to distinguish the underlying mechanism of spatial distribution. The results showed that the distribution of soil, water and nutrients was not fragmented but presented clear gradients. An overall aggregated distribution existed at most distances. No correlation was found between the spatial pattern of soil conditions and that of trees. Both positive and negative intra- and interspecific relationships were found between different DBH classes at various distances. Large trees did not show systematic inhibition of the saplings. By contrast, the inhibition intensified as the height differences increased between the compared pairs. Except for Larix, universal inhibition of saplings by upper layer trees occurred among other species, and this reflected the vertical competition for light. Therefore, we believe that competition for light rather than soil nutrients underlies the mechanism driving the formation of stand spatial pattern in the rocky mountainous areas examined.

  11. Miniinvasive paracentetic drain surgical interventions under ultrasonic control concerning liquid formations of abdominal cavity

    Directory of Open Access Journals (Sweden)

    G.I. Ohrimenko

    2013-08-01

    Full Text Available Entry. Presently miniinvasive surgical interventions under ultrasonic control became the method of choice in treatment of quite a number of abdominal and retroperitoneal organs diseases, and their complications. These operations have a row of advantages, as compared to open and laparoscopic ones: comparative simplicity, insignificant infecting of abdominal region, least of intra- and postoperative complications. Actuality of problem is conditioned by that indications to the use of paracentetic drain surgical interventions, most optimal methods of preoperative diagnostic, features of postoperative treatment of patients remain not enough studied. Research aim. To study the results of diagnostics and treatment of patients with liquid formations of abdominal cavity that were exposed to miniinvasive surgical interventions under ultrasonic control and, on the basis of it, to work out an optimal curative diagnostic algorithm. Materials and research methods. The results of treatment of 25 patients with liquid formations of abdominal cavity are analyzed. They were submitted to miniinvasive paracentetic drain surgical interventions under ultrasonic control. The pseudocysts of pancreas were in 16 patients, abscesses of abdominal cavity – in 2 patients. Research results. Intraoperative complications were not marked. Postoperative complications were observed in 5 patients. Among them there were inadequate drainage of all cavities of multicamerate abscess of the liver in 2 patients, progress of sacculated uremic peritonitis developing in presence of ascites in one patient, and arrosive hemorrhage in the cavity of pancreas pseudocyst in 2 persons. It is determined that it is necessary to include the spiral computer tomography to the complex of preoperative inspection of patients that allows to diagnose multicamerate abscess of the liver in time and to drain all the additional cavities adequately. 2 patients after paracentetic drain surgical interventions

  12. Quantum Zeno and anti-Zeno paradoxes

    Indian Academy of Sciences (India)

    anti-Zeno paradox. Here we discuss the quantum Zeno and anti-Zeno paradoxes which arise due to infinitely frequent measurements of time independent and .... follow a presentation due to Martin [11]. Consider an unstable particle B decaying into particles c + D, ... etc. B c + D,.... (10). Suppose that the total Hamiltonian H ...

  13. Negative freedom and the liberal paradoxes

    NARCIS (Netherlands)

    van Hees, M.V.B.P.M

    In their game-theoretic formulations, the liberal paradoxes of Amartya Sm and Alan Gibbard show a tension between freedom on the one hand, and Pareto optimality and stability on the other. This article examines what happens to the liberal paradoxes if a negative conception of freedom is used. Given

  14. New Paradoxes of Risky Decision Making

    Science.gov (United States)

    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.…

  15. Unearthing the Banach–Tarski Paradox

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 22; Issue 10. Unearthing the Banach–Tarski Paradox. B Sury. General Article Volume 22 Issue 10 October ... The paradox of the title can be informally described as follows.Consider the earth including the inside stuff. It is possibleto decompose this solid ...

  16. Quantum Zeno and anti-Zeno paradoxes

    Indian Academy of Sciences (India)

    Abstract. Continuous observation of a time independent projection operator is known to prevent change of state (the quantum Zeno paradox). We discuss the recent result that generic continuous measurement of time dependent projection operators will in fact ensure change of state: an anti-Zeno paradox.

  17. Tippe top paradox in relativity

    Science.gov (United States)

    Basu, Aniket; Saraswat, R. S.; Khare, Kedar B.; Sastry, G. P.; Bose, Sougato

    2002-05-01

    If a tippe top is held by its stem and spun fast on a table, it eventually tips over and stands spinning on its stem. For this to happen, the ratios of its principal moments of inertia should fall in a certain regime. Let such a top be observed from a rocket frame in which the top and the table move with a relativistic velocity. The cross-section of the top now appears elliptical due to the length contraction along the line of motion. For a fast enough rocket frame, it is possible that the ratios of the principal moments of inertia go out of the regime required for the top to tip over. However, this is paradoxical. A top that tips over in one frame should tip over in all frames. The paradox is resolved by applying the Lorentz transformation formulae to the equation of motion of the particles of the top, and going over to the spinning coordinates. All the relativistic effects such as the length contraction, time dilation, velocity addition and the lack of synchronization of clocks make their appearance. The orbits of the particles are studied analytically as well as by computer simulation. The movies on the monitor screen reveal the picturesque motion of the particles of the spinning top in the rocket frame, and show in detail how the notion of a rigid body fails in relativistic mechanics. The source code for the computer simulation is included in the appendix.

  18. [Five paradoxes in health promotion].

    Science.gov (United States)

    López-Dicastillo, Olga; Canga-Armayor, Navidad; Mujika, Agurtzane; Pardavila-Belio, Miren Idoia; Belintxon, Maider; Serrano-Monzó, Inmaculada; Pumar-Méndez, María J

    The World Health Organization states that health promotion is a key strategy to improve health, and it is conceived as a global process of enabling people to increase control over, and to improve, their health. Health promotion does not focus solely on empowering individuals dealing with their knowledge, attitudes and skills, but it also takes political, social, economic and environmental aspects influencing health and wellbeing into account. The complexity of applying these concepts is reflected in the five paradoxes in health promotion; these arise in between the rhetoric in health promotion and implementation. The detected paradoxes which are described herein involve the patient versus the person, the individual versus the group, disease professionals versus health professionals, disease indicators versus health indicators, and health as an expense versus health as an investment. Making these contradictions explicit can help determine why it is so complex to put the concepts related to health promotion into practice. It can also help to put forward aspects that need further work if health promotion is to put into practice. Copyright © 2017 SESPAS. Publicado por Elsevier España, S.L.U. All rights reserved.

  19. Computational Study of Thrombus Formation and Clotting Factor Effects under Venous Flow Conditions

    Science.gov (United States)

    2016-04-26

    generation biochemistry , and fibrin formation and function, and was able to predict essential dynamic features of the thrombus formation pro- cess observed in...Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Fort Detrick, MarylandABSTRACT A comprehensive... biochemistry , structural biology, and rheology have been extensively investigated. Such studies provide in- formation about the biochemical reactions

  20. Evaluation of seismic reflection data in the Davis and Lavender Canyons study area, Paradox Basin, Utah

    International Nuclear Information System (INIS)

    Kitcho, C.A.; Wong, I.G.; Turcotte, F.T.

    1986-08-01

    Seismic reflection data purchased from petroleum industry brokers and acquired through group speculative surveys were interpreted for information on the regional subsurface geologic structure and stratigraphy within and surrounding the Davis and Lavender Canyons study area in the Paradox Basin of southeastern Utah. Structures of interest were faults, folds, joints, and collapse structures related to salt dissolution. The seismic reflection data were used to interpret stratigraphy by identifying continuous and discontinuous reflectors on the seismic profiles. Thickening and thinning of strata and possible areas of salt flowage or dissolution could be identified from the seismic data. Identifiable reflectors included the tops of the Precambrian and Mississippian, a distinctive interbed close to the middle of the Pennsylvanian Paradox salt formation (probably the interval between Salt Cycles 10 and 13), and near the top of the Paradox salt. Of the 56 faults identified from the seismic reflection interpretation, 33 trend northwest, west-northwest, or west, and most affect only the deeper part of the stratigraphic section. These faults are part of the deep structural system found throughout the Paradox Basin, including the fold and fault belt in the northeast part of the basin. The faults bound basement Precambrian blocks that experienced minor activity during Mississippian and early Pennsylvanian deposition, and showed major displacement during early Paradox salt deposition as the Paradox Basin subsided. Based on the seismic data, most of these faults appear to have an upward terminus between the top of the Mississippian and the salt interbed reflector

  1. Modelling of fast jet formation under explosion collision of two-layer alumina/copper tubes

    Directory of Open Access Journals (Sweden)

    I Balagansky

    2017-09-01

    Full Text Available Under explosion collapse of two-layer tubes with an outer layer of high-modulus ceramics and an inner layer of copper, formation of a fast and dense copper jet is plausible. We have performed a numerical simulation of the explosion collapse of a two-layer alumina/copper tube using ANSYS AUTODYN software. The simulation was performed in a 2D-axis symmetry posting on an Eulerian mesh of 3900x1200 cells. The simulation results indicate two separate stages of the tube collapse process: the nonstationary and the stationary stage. At the initial stage, a non-stationary fragmented jet is moving with the velocity of leading elements up to 30 km/s. The collapse velocity of the tube to the symmetry axis is about 2 km/s, and the pressure in the contact zone exceeds 700 GPa. During the stationary stage, a dense jet is forming with the velocity of 20 km/s. Temperature of the dense jet is about 2000 K, jet failure occurs when the value of effective plastic deformation reaches 30.

  2. Representation and judgement of possible host rock formations and areas under consideration of geology and safety

    International Nuclear Information System (INIS)

    2005-08-01

    This comprehensive report issued by the Swiss National Cooperative for the Disposal of Radioactive Waste NAGRA takes a look at the representation and judgement of possible host rock formations and areas as far as safety and geological aspects are concerned. Nagra has to demonstrate the basic feasibility of the safe disposal of spent fuel (SF), vitrified high-level waste (HLW) and long-lived intermediate-level waste (ILW) in a deep geological repository, The report shows which possibilities for the disposal of SF, HLW and ILW exist in Switzerland and summarises the current state of general academic and applied geo-scientific research as well as the project-specific knowledge base that has been developed by Nagra over the past 30 years. The descriptions and assessments of the potential host rocks and areas are based on attributes that take into account experience gained both in Switzerland and abroad and are in agreement with international practice. An assessment of potential siting areas is looked at, in view of the preparation of a General Licence application, Nagra will also have to consider land-use planning and socio-economic aspects. This will be carried out in the next step according to the Sectoral Plan for Geological Disposal under the guidance of the relevant Swiss authorities

  3. MD simulations of onset of tungsten fuzz formation under helium irradiation

    International Nuclear Information System (INIS)

    Lasa, A.; Henriksson, K.O.E.; Nordlund, K.

    2013-01-01

    When helium (He) escapes a fusion reactor plasma, a tungsten (W)-based divertor may, under some conditions, form a fuzz-like nano-morphology. This is a highly undesired phenomenon for the divertor, and is not well understood. We performed molecular dynamics simulations of high fluence He and also C-seeded He (He+C) irradiation on W, focusing on the effect of the high fluence, the temperature and the impurities on the onset of the structure formation. We concluded that MD reproduces the experimentally found square root of time dependence of the surface growth. The He atomic density decreases when increasing the number of He atoms in the cell. A higher temperature causes a larger bubble growth and desorption activity, specially for the pure He irradiation cases. It also it leads to W recrystallization for the He+C irradiation cases. Carbon acts as a local He trap for small clusters or single atoms and causes a larger loss of crystallinity of the W surface

  4. Formation of sputtered silver clusters under bombardment with SF sub 5 sup + ions

    CERN Document Server

    Ghalab, S; Maksimov, S E; Mazarov, P; Tugushev, V I; Dzhemilev, N K; Wucher, A

    2002-01-01

    The formation of Ag sub n clusters and Ag sub n sup + cluster ions under bombardment of a silver surface with SF sub 5 sup + and Xe sup + projectile ions was investigated experimentally. In order to obtain information about the relative abundance of clusters among the flux of sputtered particles independent of their charge state, mass spectra of both secondary ions and sputtered neutral particles were recorded. The neutral species were post-ionized prior to mass analysis by means of photo-ionization using an intense UV laser at a wavelength of 193 nm. It is found that measured Ag sub n sup + signals increase significantly if SF sub 5 sup + projectiles are used instead of rare gas (Ar sup + or Xe sup +) ions of the same kinetic impact energy. The signals of neutral Ag atoms and Ag sub n clusters, on the other hand, exhibit only a relatively small increase, thus indicating that the enhancement observed for the secondary ions is predominantly caused by an increased ionization probability of sputtered particles u...

  5. CARBON STOCK IN SOIL UNDER DIFFERENT FOREST FORMATIONS, CHAPECÓ, SANTA CATARINA STATE

    Directory of Open Access Journals (Sweden)

    Rosiane Berenice Nicoloso Denardin

    2014-03-01

    Full Text Available http://dx.doi.org/10.5902/1980509813323The adoption of management practices that ensure the stability of soil organic matter also maintain the stabilityor quantitative increase of carbon (C in the lithosphere, reducing the amount of CO2 in theatmosphere. You can also minimize the losses of C to the atmosphere by using conservation practices,or using cover crops to keep the soil C stocks, and the forest cover are considered great abductionand forest systems considered large reservoirs of C. This work was performed on a property located inChapecó, Santa Catarina state, where soils were sampled from different forest formations distributedin a homogeneous soil range. The local climate is mesothermal, rainy, and the soil was characterizedas an association Cambissolo Háplico/Neossolo Litólico. The objectives were to estimate the C stocksin soils and estimate the C losses occurred due to the change of soil cover. It was evaluated soils undernatural forest (FN, of secondary stage, with a high degree of preservation; planted forest of eucalyptus(Eucalyptus saligna (PE, with eight years of cultivation, preceded by 17 years under crop conventionaltillage; and a planted forest of herb mate (Ilex paraguariensis (EM, with 25 years of cultivation underconventional system (cutting interval of 18 months, with removal of all waste produced and maintenanceof the ground without cover, with periodic use of herbicide - glyphosate. In each area were opened fourtrenches with 50 cm deep, where soil samples were collected in depths of: 0-5 cm, 5-10 cm, 10-20 cm,20-30 cm, 30-40 cm, and 40-50 cm, with kopeck rings. It was possible to determine the bulk density (Mgm-3, the soil volume per layer (depth and per hectare, and the concentration of soil C in the differentstudied areas. To quantify the C stocks equal amounts of soil were used for each depth evaluated. Itwas observed higher densities of soils and under PE and EM, to FN the lowest density are explained bythe

  6. Hydro-mechanical behaviour of two reference Belgian clay formations under non-isothermal conditions

    International Nuclear Information System (INIS)

    Lima, A.; Romero, E.; Gens, A.; Li, X.L.

    2012-01-01

    Document available in extended abstract form only. Two deep clay formations are being investigated in Belgium in connection with the design of a repository for 'High-Level Radioactive Waste': Boom clay BC at Mol (located between 160 and 270 m depths), considered the reference host formation, and Ypresian clay YC at Kallo (located between 300 and 450 m depths) as an alternative one. A comprehensive experimental programme has been carried out on these materials to explore water permeability at different temperatures and sample orientations, as well as to analyse volume change behaviour on loading/unloading at different temperatures and sample orientations (including pre and post-yield compressibility, yield properties and volume changes on drained thermal loading). Table 1 summarises some properties of BC and YC. Figure 1 presents the pore size distribution PSD curves of both clays obtained by mercury intrusion porosimetry. They display contrasting features (bi-modal pore network in YP with larger dominant pore sizes). Larger water permeability values are expected on YC as indicated in Table 1 and Figure 2, not only as a consequence of its higher void ratio but also due to these double porosity features. Water retention properties, of particular concern on sample retrieval from large depths, are also affected due to desaturation processes that are associated with the double porosity network of YP and its effects on air-entry value (a lower initial suction is measured on YP, despite being retrieved from larger depths). Figure 2 shows vertical and horizontal water permeability results under constant volume conditions and different temperatures. BC and YC display small anisotropy at sample scale - permeability is slightly larger on horizontal direction-. With regard to temperature effects, the figure shows that water permeability dependency on temperature in YC is slightly higher than the water viscosity prediction for both orientations. Instead BC displayed a thermal

  7. Paradoxical Behavior of Granger Causality

    Science.gov (United States)

    Witt, Annette; Battaglia, Demian; Gail, Alexander

    2013-03-01

    Granger causality is a standard tool for the description of directed interaction of network components and is popular in many scientific fields including econometrics, neuroscience and climate science. For time series that can be modeled as bivariate auto-regressive processes we analytically derive an expression for spectrally decomposed Granger Causality (SDGC) and show that this quantity depends only on two out of four groups of model parameters. Then we present examples of such processes whose SDGC expose paradoxical behavior in the sense that causality is high for frequency ranges with low spectral power. For avoiding misinterpretations of Granger causality analysis we propose to complement it by partial spectral analysis. Our findings are illustrated by an example from brain electrophysiology. Finally, we draw implications for the conventional definition of Granger causality. Bernstein Center for Computational Neuroscience Goettingen

  8. Paradoxes unbounded: Practising community making

    Directory of Open Access Journals (Sweden)

    Tess Maginess

    2011-10-01

    Full Text Available The first section of this paper is a discussion of the paradoxes contained in definitionsof the word 'community' and deliberately foregrounds and makes problematicconflicting meanings before arguing for a third definition and practice of community.This third definition and practice celebrates and even transcends contradictions withinan active learning model of education in the community, aimed at tackling inequalityand prejudice. The second section offers an autocritical narrative account of aneducation in the community project that illustrates how such a practice of communitymaking can be achieved within an educational framework in which pupil is teacher andteacher is pupil and in which an imaginative, creative approach is deployed toconstruct a community making practice. The paper draws on understandings fromcommunity development, inclusive and creative education, emancipatory actionresearch, postcolonial and post-structuralist theory.

  9. Standard format and content of financial assurance mechanisms required for decommissioning under 10 CFR parts 30, 40, 70, and 72

    International Nuclear Information System (INIS)

    1990-06-01

    The purpose of this regulatory guide, ''Standard Format and Content of Financial Assurance Mechanisms Required for Decommissioning Under 10 CFR Parts 30, 40, 70, and 72,'' is to provide guidance acceptable to the NRC staff on the information to be provided for establishing financial assurance for decommissioning and to establish a standard format for presenting the information. Use of the standard format will help ensure that the financial instruments contain the information required by 10 CFR Parts 30, 40, 70, and 72; aid the applicant and NRC staff in ensuring that the information is complete; and help persons reading the financial instruments to locate information. This guide address financial assurance for decommissioning of facilities under materials licenses granted under Parts 30, 40, 70, and 72. These parts include licensees in the following categories: Part 30, Byproduct Material; Part 40, Source Material; Part 70, Special Nuclear Material; and Part 72, Independent Spent Fuel Storage Installations

  10. Formation of dwarf ellipticals and dwarf irregular galaxies by interaction of giant galaxies under environmental influence

    OpenAIRE

    Chattopadhyay, Tanuka; Debsarma, Suma; Karmakar, Pradip; Davoust, Emmanuel

    2014-01-01

    A model is proposed for the formation of gas-rich dwarf irregular galaxies and gas-poor, rotating dwarf elliptical galaxies following the interaction between two giant galaxies as a function of space density. The formation of dwarf galaxies is considered to depend on a random variable, the tidal index theta, an environmental parameter defined by Karachentsev et al. (2004), such that for theta less than zero, the formation of dwarf irregular galaxy is assured whereas for theta greater than zer...

  11. Distributed Formation State Estimation Algorithms Under Resource and Multi-Tasking Constraints, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Recent work has developed a number of architectures and algorithms for accurately estimating spacecraft and formation states. The estimation accuracy achievable...

  12. Dynamical pattern formation in a low-concentration magnetorheological fluid under two orthogonal sinusoidal fields

    International Nuclear Information System (INIS)

    Yépez, L.D.; Carrillo, J.L.; Donado, F.; Sausedo-Solorio, J.M.; Miranda-Romagnoli, P.

    2016-01-01

    The dynamical pattern formation of clusters of magnetic particles in a low-concentration magnetorheological fluid, under the influence of a superposition of two perpendicular sinusoidal fields, is studied experimentally. By varying the frequency and phase shift of the perpendicular fields, this configuration enables us to experimentally analyze a wide range of field configurations, including the case of a pure rotating field and the case of an oscillating unidirectional field. The fields are applied parallel to the horizontal plane where the fluid lies or in the vertical plane. For fields applied in the horizontal plane, we observed that, when the ratio of the frequencies increases, the average cluster size exhibits a kind of periodic resonances. When the phase shift between the fields is varied, the average chain length reaches maximal values for the cases of the rotating field and the unidirectional case. We analyze and discuss these results in terms of a weighted average of the time-dependent Mason number. In the case of a rotating field on the vertical plane, we also observe that the competition between the magnetic and the viscous forces determines the average cluster size. We show that this configuration generates a series of physically meaningful self-organization of clusters and transport phenomena. - Highlights: • A weighted average of the time-dependent Mason number is proposed. • The self-propelling clusters appear when a vertical rotating magnetic field is applied. • The largest average chain lengths are reached when frequencies are multiples one another. • Rotating and unidirectional alternating fields produce the largest average chain length values.

  13. Dynamical pattern formation in a low-concentration magnetorheological fluid under two orthogonal sinusoidal fields

    Energy Technology Data Exchange (ETDEWEB)

    Yépez, L.D.; Carrillo, J.L. [Instituto de Física de la Universidad Autónoma de Puebla, Ciudad Universitaria, Edif. 110 A, Puebla 72570 (Mexico); Donado, F.; Sausedo-Solorio, J.M.; Miranda-Romagnoli, P. [Instituto de Ciencias Básicas e Ingeniería Universidad Autónoma del Estado de Hidalgo, Pachuca 42090, Pachuca (Mexico)

    2016-06-15

    The dynamical pattern formation of clusters of magnetic particles in a low-concentration magnetorheological fluid, under the influence of a superposition of two perpendicular sinusoidal fields, is studied experimentally. By varying the frequency and phase shift of the perpendicular fields, this configuration enables us to experimentally analyze a wide range of field configurations, including the case of a pure rotating field and the case of an oscillating unidirectional field. The fields are applied parallel to the horizontal plane where the fluid lies or in the vertical plane. For fields applied in the horizontal plane, we observed that, when the ratio of the frequencies increases, the average cluster size exhibits a kind of periodic resonances. When the phase shift between the fields is varied, the average chain length reaches maximal values for the cases of the rotating field and the unidirectional case. We analyze and discuss these results in terms of a weighted average of the time-dependent Mason number. In the case of a rotating field on the vertical plane, we also observe that the competition between the magnetic and the viscous forces determines the average cluster size. We show that this configuration generates a series of physically meaningful self-organization of clusters and transport phenomena. - Highlights: • A weighted average of the time-dependent Mason number is proposed. • The self-propelling clusters appear when a vertical rotating magnetic field is applied. • The largest average chain lengths are reached when frequencies are multiples one another. • Rotating and unidirectional alternating fields produce the largest average chain length values.

  14. Formation of Fine Structures in Uniform Suspension under Standing Waves Action

    Science.gov (United States)

    Kalinichenko, V. F.; Chashechkin, Yu. D.

    2012-04-01

    Structurization of initially uniform suspension in fields of standing gravity waves was studied in a rectangular tank oscillating in vertical direction. The tank with aspect ratio of 50:4 was placed at shaker table with a low level of horizontal components of acceleration during the motion. Diluted aluminum powder suspension in water filled in tank with was undergone wave action in frequency range corresponding to first and second modes of intrinsic oscillations. For visualizations and tracers velocity measurements a digital high-speed video camera was used. The formation of large and small scale structures in initially uniform suspension was registered. Experiments were performed in tanks with flat smooth and rough bottom as well as with water above stationary ripples and deformable sand riffles. Large and small scales irregularities of initially smooth field of concentration were observed in the whole volume of the fluid. Large voids with shapes reminding the bottom topography features were formed first. Later the fine extended filaments were observed. Their horizontal scales were determined by bed forms extension, and the vertical scale grows in time. Depending on the wave mode the filament structures arose from the bottom or sank from the free surface. The evolution of the structure geometrical parameters were measured both in vertical and horizontal directions. The difference of dynamical behaviour of suspension concentration in vicinity and far from free surface, flat bottom or bed topography was determined and discussed. In theoretical description of the flow compete fundamental set of governing equations. Complete solution of the set contains family of thin singular perturbed components which are characterized by singular perturbed functions. These flow components can accumulate of admixtures and maintain non-uniform pattern of admixture concentration. The presented experiments were performed on set-up USU "HPC IPMec RAS" under support of Ministry of

  15. Arbuscular mycorrhiza formation and its function under elevated atmospheric O3: A meta-analysis.

    Science.gov (United States)

    Wang, Shuguang; Augé, Robert M; Toler, Heather D

    2017-07-01

    We quantitatively evaluated the effects of elevated O 3 on arbuscular mycorrhiza (AM) formation and on AM role in promoting plant growth in regard to several moderating variables (O 3 levels, O 3 exposure duration, plant types, AM fungi family, and additional stress) by means of meta-analysis of published data. The analysis consisted of 117 trials representing 20 peer-reviewed articles and 16 unpublished trials. Relative to non-mycorrhizal controls, AM inoculation did not significantly alter plant growth (shoot biomass, root biomass, total biomass and plant height) when O 3 concentration was less than 80 ppb, but at concentrations above 80 ppb symbiosis was associated with increases of 68% in shoot biomass and 131% in root biomass. AM effects on plant growth were affected by the duration of O 3 exposure but did not differ much with AM fungi taxa or plant type. AM symbiosis has also led to higher yields under O 3 stress, relative to the non-mycorrhizal plants, and the AM effects have been more pronounced as O 3 concentration increases. As with biomass, AM effects on yield have been affected by the duration of O 3 exposure, with the greatest increase (100%) occurring at 61-90 d. AM-induced promotion of yield differed with fungal species but not with plant type or other abiotic stress. Colonization of roots by AM fungi has been negatively affected by elevated O 3 compared to ambient O 3 ; total mycorrhizal colonization rate (MCR), arbuscular MCR, vesicular MCR and hyphal coil MCR declined as O 3 levels rose. AM colonization rates were affected by duration of O 3 exposure, plant type, AM fungal taxa and other concurrent stresses in most cases. The analysis showed that AM inoculation has the potential to ameliorate detrimental effects of elevated O 3 on plant growth and productivity, despite colonization rates being negatively affected by elevated O 3 . Copyright © 2017. Published by Elsevier Ltd.

  16. Chemistry teacher initial formation under the eye of the coordinators of the courses

    Directory of Open Access Journals (Sweden)

    Roberta Guimarães Corrêa

    2016-05-01

    Full Text Available Despite the recognition of the need for change and the constant production of studies on initial formation, the degree courses still have questions that need to be discussed. These issues are related to the difficulty to overcome the lack of teachers in basic education and the type of formation offered in undergraduate courses, which does not seem to meet the current Brazilian educational demands. This paper presents data from a qualitative study conducted with coordinators of seven higher education institutions in the state of São Paulo. Despite the different institutional realities presented in this work, the difficulty of effectively contribute to the formation of chemistry teachers is common to all the institutions. Lack of interest in initial formation teacher’s courses, evasion problems, relationship between the initial formation of chemical teachers and chemistry’s professionals and the lack of commitment of teachers marked the reports of the coordinators of the courses.

  17. Geologic appraisal of Paradox basin salt deposits for water emplacement

    Science.gov (United States)

    Hite, Robert J.; Lohman, Stanley William

    1973-01-01

    Thick salt deposits of Middle Pennsylvanian age are present in an area of 12,000 square miles in the Paradox basin of southeast Utah and southwest Colorado. The deposits are in the Paradox Member of the Hermosa Formation. The greatest thickness of this evaporite sequence is in a troughlike depression adjacent to the Uncompahgre uplift on the northeast side of the basin.The salt deposits consist of a cyclical sequence of thick halite units separated by thin units of black shale, dolomite, and anhydrite. Many halite units are several hundred feet thick and locally contain economically valuable potash deposits.Over much of the Paradox basin the salt deposits occur at depths of more than 5,000 feet. Only in a series of salt anticlines located along the northeastern side of the basin do the salt deposits rise to relatively shallow depths. The salt anticlines can be divided geographically and structurally into five major systems. Each system consists of a long undulating welt of thickened salt over which younger rocks are arched in anticlinal form. Locally there are areas along the axes of the anticlines where the Paradox Member was never covered by younger sediments. This allowed large-scale migration of Paradox strata toward and up through these holes in the sediment cover forming diapiric anticlines.The central or salt-bearing cores of the anticlines range in thickness from about 2,500 to 14,000 feet. Structure in the central core of the salt anticlines is the result of both regional-compression and flowage of the Paradox Member into the anticlines from adjacent synclines. Structure in the central cores of the salt anticlines ranges from relatively undeformed beds to complexly folded and faulted masses, in which stratigraphic continuity is undemonstrable.The presence of thick cap rock .over many of the salt anticlines is evidence of removal of large volumes of halite by groundwater. Available geologic and hydrologic information suggests that this is a relatively slow

  18. Growth of silicone-immobilized bacteria on polycarbonate membrane filters, a technique to study microcolony formation under anaerobic conditions.

    OpenAIRE

    Højberg, O; Binnerup, S J; Sørensen, J

    1997-01-01

    A technique was developed to study microcolony formation by silicone-immobilized bacteria on polycarbonate membrane filters under anaerobic conditions. A sudden shift to anaerobiosis was obtained by submerging the filters in medium which was depleted for oxygen by a pure culture of bacteria. The technique was used to demonstrate that preinduction of nitrate reductase under low-oxygen conditions was necessary for nonfermenting, nitrate-respiring bacteria, e.g., Pseudomonas spp., to cope with a...

  19. six six six paradox : [luuletused] / Triin Tasuja

    Index Scriptorium Estoniae

    Tasuja, Triin

    2008-01-01

    Sisu: six six six paradox ; cat stevens ; "vahel tundub, et mu ümber..." ; sääse ; Salaalaealised ; kolkalapsed ; longin mööda lumiseid tänavaid ; punkrock dekadents ; "Igast kirjaneitsist..." ; "mina olengi see saikochick..."

  20. Distributed Adaptive Finite-Time Approach for Formation-Containment Control of Networked Nonlinear Systems Under Directed Topology.

    Science.gov (United States)

    Wang, Yujuan; Song, Yongduan; Ren, Wei

    2017-07-06

    This paper presents a distributed adaptive finite-time control solution to the formation-containment problem for multiple networked systems with uncertain nonlinear dynamics and directed communication constraints. By integrating the special topology feature of the new constructed symmetrical matrix, the technical difficulty in finite-time formation-containment control arising from the asymmetrical Laplacian matrix under single-way directed communication is circumvented. Based upon fractional power feedback of the local error, an adaptive distributed control scheme is established to drive the leaders into the prespecified formation configuration in finite time. Meanwhile, a distributed adaptive control scheme, independent of the unavailable inputs of the leaders, is designed to keep the followers within a bounded distance from the moving leaders and then to make the followers enter the convex hull shaped by the formation of the leaders in finite time. The effectiveness of the proposed control scheme is confirmed by the simulation.

  1. The Formation of Teacher Work Teams under Adverse Conditions: Towards a More Realistic Scenario for Schools in Distress

    Science.gov (United States)

    Mintrop, Rick; Charles, Jessica

    2017-01-01

    Group formation studies are rare in the literature on teacher professional learning communities (PLCs). But they are needed to render realistic scenarios and design interventions for practitioners who work in schools where teachers encounter distress and social adversity. Under these conditions, we may need approaches to PLC development that are…

  2. Patent Foramen Ovale: Is Stroke Due to Paradoxical Embolism?

    Science.gov (United States)

    Ranoux, D.; Cohen, A.; Cabanes, L.; Amarenco, P.; Bousser, M. G.; Mas, J. L.

    1993-01-01

    Background and Purpose: A patent foramen ovale has been reported to be significantly more frequent in young stroke patients than in matched control subjects, and paradoxical embolism has been suggested as the main mechanism of stroke in-this situation. The present study was designed to test this hypothesis. Methods: Sixty-eight consecutive patients under 55 years of age presenting with an ischemic stroke had an extensive workup, including transesophageal echocardiography with contrast. We compared the prevalence of criteria for the diagnosis of paradoxical embolism in patients with and without a patent foramen ovale. Results: A patent foramen ovale was found in 32 patients (47%). A Valsalva-provoking activity was present at stroke onset in six patients with a patent foramen ovale and in eight patients with no patent foramen ovale (X(sup 2)=0.1, nonsignificant). Clinical/radiological features suggestive of an embolic mechanism were not more frequent in patients with a patent foramen ovale. Clinical evidence of deep vein thrombosis was present in one patient with a patent foramen ovale and in none of the others. No occult venous thrombosis was found in a subgroup of patients with a patent foramen ovale and no definite cause for stroke who underwent venography (n=13). Conclusions. Our results do not support the hypothesis that paradoxical embolism is the primary mechanism of stroke in patients with a patent foramen ovale. (Stroke 1993;24:31-34) KEY WORDS e cerebral ischemia e embolism foramen ovale, patent

  3. The diagnosis and treatment of paradoxical embolism: a systematic review

    Directory of Open Access Journals (Sweden)

    Atooshe Rohani

    2016-11-01

    Full Text Available One in five adults has patent foramen ovale (PFO, which is typically without symptoms. Because of the low pressure in both atria and the anatomical position of the septum secundum, there is no left-to-right shunting and little right-to-left shunting in the general condition; however, when the right atrial pressure increases, this slit-like flap separates and allows right-to-left shunting. According to the Johnson criteria, simultaneous occurrences of arterial emboli, such as those caused by cerebrovascular accident or pulmonary embolism, demonstrate the presence of paradoxical embolism through a PFO. When a patient presents with multivascular arterial embolism, the clinician should perform a contrast transthoracic echo, a transesophageal (TEE, a real-time three-dimensional TEE, and even an intracardiac echocardiography (ICE in order to differentiate between PFO, flat atrial septal defect (ASD and hybrid defects. The randomized trials that have assessed therapeutic interventions for paradoxical embolism have not produced any clear guidelines as to how best to treat this condition. The classic treatment is surgical embolectomy with exploration of the right chambers and the pulmonary arteries under full cardiopulmonary bypass. Patients with a history of ≥1 paradoxical embolism may be indicated for device PFO closure.

  4. Distributed Formation State Estimation Algorithms Under Resource and Multi-Tasking Constraints, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Recent work on distributed multi-spacecraft systems has resulted in a number of architectures and algorithms for accurate estimation of spacecraft and formation...

  5. Scale Formation under Blended Phosphate Treatment for a Utility with Lead Pipes

    Science.gov (United States)

    Conventional wisdom hypothesizes that the orthophosphate component of blended phosphate corrosion inhibitors causes the formation of low solubility lead-orthophosphate solids which inhibit lead release into drinking water. This study characterized the composition and morphology o...

  6. Evidence for the role of organics in aerosol particle formation under atmospheric conditions

    International Nuclear Information System (INIS)

    Metzger, A.; Dommen, J.; Duplissy, J.; Prevot, A.S.H.; Weingartner, E.; Baltensperger, U.; Verheggen, B.; Riipinen, I.; Kulmala, M.; Spracklen, D.V.; Carslaw, K.S.

    2010-01-01

    New particle formation in the atmosphere is an important parameter in governing the radiative forcing of atmospheric aerosols. However, detailed nucleation mechanisms remain ambiguous, as laboratory data have so far not been successful in explaining atmospheric nucleation. We investigated the formation of new particles in a smog chamber simulating the photochemical formation of H2SO4 and organic condensable species. Nucleation occurs at H2SO4 concentrations similar to those found in the ambient atmosphere during nucleation events. The measured particle formation rates are proportional to the product of the concentrations of H2SO4 and an organic molecule. This suggests that only one H2SO4 molecule and one organic molecule are involved in the rate-limiting step of the observed nucleation process. Parameterizing this process in a global aerosol model results in substantially better agreement with ambient observations compared to control runs.

  7. Chemistry teacher initial formation under the eye of the coordinators of the courses

    OpenAIRE

    Roberta Guimarães Corrêa; Rosebelly Nunes Marques

    2016-01-01

    Despite the recognition of the need for change and the constant production of studies on initial formation, the degree courses still have questions that need to be discussed. These issues are related to the difficulty to overcome the lack of teachers in basic education and the type of formation offered in undergraduate courses, which does not seem to meet the current Brazilian educational demands. This paper presents data from a qualitative study conducted with coordinators of seven higher ed...

  8. Paradoxical tuberculosis-associated immune reconstitution inflammatory syndrome in children.

    Science.gov (United States)

    Van Rie, Annelies; Sawry, Shobna; Link-Gelles, Ruth; Madhi, Shabir; Fairlie, Lee; Verwey, Charl; Mahomed, Nasreen; Murdoch, David; Moultrie, Harry

    2016-02-01

    Paradoxical tuberculosis (TB)-associated Immune Reconstitution Inflammatory Syndrome (IRIS) is a common complication of combination antiretroviral treatment (cART) initiation in adults residing in resource-limited regions. Little is known about the burden and presentation of TB-IRIS in children initiating cART while receiving TB treatment. Prospective cohort study of South African children initiating cART while on TB treatment. Children were assessed clinically and by chest x-ray before starting cART and at 2, 4, 6, and 12 weeks post cART initiation. All children who presented with any signs or symptoms suggestive of paradoxical TB-IRIS were classified according to the consensus adult TB-IRIS case definition developed by the International Network for Study of HIV-associated IRIS (INSHI) and reviewed by an independent expert panel. In 7 of the 104 children enrolled in the cohort, symptoms and/or clinical or radiological signs suggestive of paradoxical TB-IRIS developed after a median of 14 days of cART. In two of these cases, there was agreement between the INSHI case definition and the expert panel. In an additional 3 cases, the INSHI criteria were fulfilled but the expert panel made an alternative diagnosis of pneumonia (n = 2) and poor adherence to cART (n = 1). The burden of paradoxical TB-IRIS in children with underlying TB initiating cART is low. Including response to antibiotic treatment for pneumonia as a criterion for an alternative diagnosis may improve the specificity of the INSHI case definition. © 2015 Wiley Periodicals, Inc.

  9. Biodegradation of triclosan and formation of methyl-triclosan in activated sludge under aerobic conditions

    DEFF Research Database (Denmark)

    Chen, Xijuan; Nielsen, Jeppe Lund; Furgal, Karolina

    2011-01-01

    of triclosan- methyl was investigated in activated sludge from a standard activated sludge WWTP equipped with enhanced biological phosphorus removal. The removal was found to occur mainly under aerobic conditions while under anoxic (nitrate reducing) and anaerobic conditions rather low removal rates were...... determined. In a laboratory-scale activated sludge reactor 75% of the triclosan was removed under aerobic conditions within 150 h, while no removal was observed under anaerobic or anoxic conditions. One percent of the triclosan was converted to triclosan-methyl under aerobic conditions, less under anoxic...

  10. Cannabis and sex: multifaceted paradoxes.

    Science.gov (United States)

    Cohen, S

    1982-01-01

    At the present level of ignorance about sexuality and cannabis, what rational position can be adopted? First, it must be recognized that even without cannabis, current involvement in sex-related activities may well have been called "promiscuous" by a preceding generation or two. The general loosening of morality, the erosion of family, church and other authoritarian controls, The Pill, antibiotics and other recent developments have contributed to current casual attitudes. Although one may not perceive it, counterculture beliefs have had their impact on the dominant culture. Marijuana has some enhancing effect upon sexual proceedings for some individuals. It may be sexually evocative and gratifying. Nonspecific factors play an important role in this matter. Opposite effects also occur, and an endocrinologic basis for actual diminution of drives and potency may exist. The final paradox is that cannabis' employment for sexual arousal is predominantly an activity of young adults. The older age groups most in need of sexual support and assistance are less frequently involved in its use. It is unclear why this dichotomy between need and utilization exists.

  11. The Paradox of Equal Opportunities

    Directory of Open Access Journals (Sweden)

    Mitja Sardoč

    2014-06-01

    Full Text Available The basic assumption of the idea of equal opportunities is based on the assertion that all individuals competing for an advantaged social position should have equal opportunities, i.e., that each and every one of them should have fair opportunities to achieve a particular goal. Despite the fact that equal opportunities is one of the basic mechanisms for a just distribution of advantageous social positions, the idea of fair equality of opportunity remains divided between different competing political projects, e.g., egalitarian liberalism, libertarian political theory, multiculturalism, etc. This paper examines two basic dimensions of equal opportunities to which existing conceptions fail to offer a unanimous answer, i.e., a the issue of fairness and b the issue of the currency of fairness. The concluding part of this paper presents two basic paradoxes that determine both the direction of the discussion as well as the possible solutions to the achievement of fair equal opportunities as part of any process for competing for advantageous social positions.

  12. [Mechanistic modelling allows to assess pathways of DNA lesion interactions underlying chromosome aberration formation].

    Science.gov (United States)

    Eĭdel'man, Iu A; Slanina, S V; Sal'nikov, I V; Andreev, S G

    2012-12-01

    The knowledge of radiation-induced chromosomal aberration (CA) mechanisms is required in many fields of radiation genetics, radiation biology, biodosimetry, etc. However, these mechanisms are yet to be quantitatively characterised. One of the reasons is that the relationships between primary lesions of DNA/chromatin/chromosomes and dose-response curves for CA are unknown because the pathways of lesion interactions in an interphase nucleus are currently inaccessible for direct experimental observation. This article aims for the comparative analysis of two principally different scenarios of formation of simple and complex interchromosomal exchange aberrations: by lesion interactions at chromosome territories' surface vs. in the whole space of the nucleus. The analysis was based on quantitative mechanistic modelling of different levels of structures and processes involved in CA formation: chromosome structure in an interphase nucleus, induction, repair and interactions of DNA lesions. It was shown that the restricted diffusion of chromosomal loci, predicted by computational modelling of chromosome organization, results in lesion interactions in the whole space of the nucleus being impossible. At the same time, predicted features of subchromosomal dynamics agrees well with in vivo observations and does not contradict the mechanism of CA formation at the surface of chromosome territories. On the other hand, the "surface mechanism" of CA formation, despite having certain qualities, proved to be insufficient to explain high frequency of complex exchange aberrations observed by mFISH technique. The alternative mechanism, CA formation on nuclear centres is expected to be sufficient to explain frequent complex exchanges.

  13. Temperature dependence of underdense nanostructure formation in tungsten under helium irradiation

    International Nuclear Information System (INIS)

    Valles, G.; Martin-Bragado, I.; Nordlund, K.; Lasa, A.; Björkas, C.; Safi, E.; Perlado, J.M.; Rivera, A.

    2017-01-01

    Recently, tungsten has been found to form a highly underdense nanostructured morphology (“W fuzz”) when bombarded by an intense flux of He ions, but only in the temperature window 900–2000 K. Using object kinetic Monte Carlo simulations (pseudo-3D simulations) parameterized from first principles, we show that this temperature dependence can be understood based on He and point defect clustering, cluster growth, and detrapping reactions. At low temperatures (<900 K), fuzz does not grow because almost all He is trapped in very small He-vacancy clusters. At high temperatures (>2300 K), all He is detrapped from clusters, preventing the formation of the large clusters that lead to fuzz growth in the intermediate temperature range. - Highlights: •OKMC simulation of temperature window for fuzz formation. •Stable He-V clusters prevent fuzz formation at low temperatures. •Dissociation of He-V clusters prevent fuzz formation at high temperatures. •Fuzz formation rate increases with increasing temperature. •An incubation fluence observed in the simulations, similar to experimental observations.

  14. High-Burnup-Structure (HBS): Model Development in MARMOT for HBS Formation and Stability Under Radiation and High Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, K. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Bai, X. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zhang, Y. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Biner, B. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-09-01

    A detailed phase field model for the formation of High Burnup Structure (HBS) was developed and implemented in MARMOT. The model treats the HBS formation as an irradiation-induced recrystallization. The model takes into consideration the stored energy associated with dislocations formed under irradiation. The accumulation of radiation damage, hence, increases the system free energy and triggers recrystallization. The increase in the free energy due to the formation of new grain boundaries is offset by the reduction in the free energy by creating dislocation-free grains at the expense of the deformed grains. The model was first used to study the growth of recrystallized flat and circular grains. The model reults were shown to agree well with theorrtical predictions. The case of HBS formation in UO2 was then investigated. It was found that a threshold dislocation density of (or equivalently a threshold burn-up of 33-40 GWd/t) is required for HBS formation at 1200K, which is in good agrrement with theory and experiments. In future studies, the presence of gas bubbles and their effect on the formation and evolution of HBS will be considered.

  15. High-Burnup-Structure (HBS): Model Development in MARMOT for HBS Formation and Stability Under Radiation and High Temperature

    International Nuclear Information System (INIS)

    Ahmed, K.; Bai, X.; Zhang, Y.; Biner, B.

    2016-01-01

    A detailed phase field model for the formation of High Burnup Structure (HBS) was developed and implemented in MARMOT. The model treats the HBS formation as an irradiation-induced recrystallization. The model takes into consideration the stored energy associated with dislocations formed under irradiation. The accumulation of radiation damage, hence, increases the system free energy and triggers recrystallization. The increase in the free energy due to the formation of new grain boundaries is offset by the reduction in the free energy by creating dislocation-free grains at the expense of the deformed grains. The model was first used to study the growth of recrystallized flat and circular grains. The model results were shown to agree well with theoretical predictions. The case of HBS formation in UO2 was then investigated. It was found that a threshold dislocation density of (or equivalently a threshold burn-up of 33-40 GWd/t) is required for HBS formation at 1200K, which is in good agreement with theory and experiments. In future studies, the presence of gas bubbles and their effect on the formation and evolution of HBS will be considered.

  16. Molecular Mechanisms Underlying the Link between Nuclear Receptor Function and Cholesterol Gallstone Formation

    Directory of Open Access Journals (Sweden)

    Mary Carmen Vázquez

    2012-01-01

    Full Text Available Cholesterol gallstone disease is highly prevalent in western countries, particularly in women and some specific ethnic groups. The formation of water-insoluble cholesterol crystals is due to a misbalance between the three major lipids present in the bile: cholesterol, bile salts, and phospholipids. Many proteins implicated in biliary lipid secretion in the liver are regulated by several transcription factors, including nuclear receptors LXR and FXR. Human and murine genetic, physiological, pathophysiological, and pharmacological evidence is consistent with the relevance of these nuclear receptors in gallstone formation. In addition, there is emerging data that also suggests a role for estrogen receptor ESR1 in abnormal cholesterol metabolism leading to gallstone disease. A better comprehension of the role of nuclear receptor function in gallstone formation may help to design new and more effective therapeutic strategies for this highly prevalent disease condition.

  17. Multishell structure formation in Ni nanowire under uniaxial strain along <0 0 1> crystallographic direction: A molecular dynamics simulation

    Energy Technology Data Exchange (ETDEWEB)

    Wang Li, E-mail: wanglihxf@sdu.edu.c [School of Mechanical and Electrical Engineering, Shandong University at Weihai, 180 Wenhuaxi Road, Weihai 264209 (China); Peng Chuanxiao [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Gong Jianhong [School of Mechanical and Electrical Engineering, Shandong University at Weihai, 180 Wenhuaxi Road, Weihai 264209 (China)

    2010-04-01

    Molecular dynamics simulations based upon embedded-atom-method potential are employed to explore the fracture behavior of Ni nanowire along <0 0 1> crystallographic direction at temperature of 300 K. We find the formation of (5,5) multishell structure (MS), which is transformed from (6,5) MS at the necking region of nanowire under the strain rate of 0.02%ps{sup -1}. A reorientation transformation from <0 0 1> to <1 1 0> is first detected before formation of (6,5) MS. The formed (5,5) MS is more stable and can be tensioned longer as lower strain rate is loaded.

  18. Professional Motivation Formation of Future Specialists under the Conditions of Regional Educational Complex

    Science.gov (United States)

    Kargina, Elena Mikhaylovna

    2015-01-01

    Motivation plays the leading role in the organization of the personality structure. It is a driving force of the activity. Motivation accounts for the behavior and activity and has a great impact on professional self-determination and person's satisfaction with the work. The problem of professional motivation formation of a future specialist is…

  19. Forces of Change: Mechanics Underlying Formation of Functional 3D Organ Buds

    OpenAIRE

    Wrighton, Paul J.; Kiessling, Laura L.

    2015-01-01

    3D organ buds that can recapitulate organ function have myriad applications for regenerative and personalized medicine. Here, Takebe et al. (2015) describe a generalized method for organ bud formation, demonstrating that mechanosensitive mesenchymal stem cells drive condensation of heterotypic cell mixtures to create buds from diverse organs.

  20. Forces of Change: Mechanics Underlying Formation of Functional 3D Organ Buds.

    Science.gov (United States)

    Wrighton, Paul J; Kiessling, Laura L

    2015-05-07

    3D organ buds that can recapitulate organ function have myriad applications for regenerative and personalized medicine. Here, Takebe et al. (2015) describe a generalized method for organ bud formation, demonstrating that mechanosensitive mesenchymal stem cells drive condensation of heterotypic cell mixtures to create buds from diverse organs. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Formation of Ni/C based polyacrylonitrile nanocomposites under IR-radiation

    Directory of Open Access Journals (Sweden)

    Dmitriy G. Muratov

    2016-09-01

    By calculating the total Gibbs energy of possible reduction reactions of nickel chloride and oxide pyrolysis PAN products we have shown the possibility of the formation of nanocomposites comprising nickel oxide nanoparticles which can be reduced to zero-valence state at higher temperature IR heating (more than 5000 °C.

  2. Formation and adaptation of memory : Neurobiological mechanisms underlying learning and reversal learning

    NARCIS (Netherlands)

    Havekes, Robbert

    2008-01-01

    The hippocampus is a brain region that plays a critical role in memory formation. In addition, it has been suggested that this brain region is important for ‘updating’ information that is incorrect or outdated. The main goal of this thesis project was to investigate which neurobiological processes

  3. FORMATION OF PYROMORPHITE IN ANGLESITE-HYDROXYAPATITE SUSPENSIONS UNDER VARYING PH CONDITIONS

    Science.gov (United States)

    Addition of phosphate to lead [Pb(II)] contaminated soil to immobilize soil Pb by formation of pyromorphite has been proposed as an alternative remediation technique. Lead sulfate (PbSO4, anglesite), a Pb-bearing form found in contaminated soils and wastes, was reacted with a sy...

  4. Nanotwin Formation in High-Manganese Austenitic Steels Under Explosive Shock Loading

    Science.gov (United States)

    Canadinc, D.; Uzer, B.; Elmadagli, M.; Guner, F.

    2018-04-01

    The micro-deformation mechanisms active in a high-manganese austenitic steel were investigated upon explosive shock loading. Single system of nanotwins forming within primary twins were shown to govern the deformation despite the elevated temperatures attained during testing. The benefits of nanotwin formation for potential armor materials were demonstrated.

  5. Electrochemical studies of the film formation on lithium in propylene carbonate solutions under open circuit conditions

    Energy Technology Data Exchange (ETDEWEB)

    Geronov, Y. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Schwager, F. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Muller, R. H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    1981-06-01

    The nature of protective surface layers formed on lithium in propylene carbonate solutions of and at open circuit has been investigated by electrochemical pulse measurements. The results are consistent with the fast formation of a compact thin layer resulting from the reaction with residual water. This layer acts as a solid ionic conductor. Slow corrosion or decomposition processes produce a thicker porous overlayer.

  6. Formation of imines by selective gold-catalysed aerobic oxidative coupling of alcohols and amines under ambient conditions

    DEFF Research Database (Denmark)

    Kegnæs, Søren; Mielby, Jerrik Jørgen; Mentzel, Uffe Vie

    2010-01-01

    The formation of imines by aerobic oxidative coupling of mixtures of alcohols and amines was studied using gold nanoparticles supported on titanium dioxide, TiO2, as a heterogeneous catalyst. The reactions were performed at ambient conditions (room temperature and atmospheric pressure) and occurr......-product represents a new green reaction protocol for imine formation.......The formation of imines by aerobic oxidative coupling of mixtures of alcohols and amines was studied using gold nanoparticles supported on titanium dioxide, TiO2, as a heterogeneous catalyst. The reactions were performed at ambient conditions (room temperature and atmospheric pressure) and occurred...... with excellent selectivity (above 98%) at moderate conversion under optimized conditions. The effect of catalytic amounts of different bases was studied, along with reaction temperature and time. Utilisation of a selective catalyst system that uses dioxygen as an oxidant and only produces water as by...

  7. Nod factor supply under water stress conditions modulates cytokinin biosynthesis and enhances nodule formation and N nutrition in soybean.

    Science.gov (United States)

    Prudent, Marion; Salon, Christophe; Smith, Donald L; Emery, R J Neil

    2016-09-01

    Nod factors (NF) are molecules produced by rhizobia which are involved in the N 2 -fixing symbiosis with legume plants, enabling the formation of specific organs called nodules. Under drought conditions, nitrogen acquisition by N 2 -fixation is depressed, resulting in low legume productivity. In this study, we evaluated the effects of NF supply on nitrogen acquisition and on cytokinin biosynthesis of soybean plants grown under drought. NF supply to water stressed soybeans increased the CK content of all organs. The profile of CK metabolites also shifted from t-Z to cis-Z and an accumulation of nucleotide and glucoside conjugates. The changes in CK coincided with enhanced nodule formation with sustained nodule specific activity, which ultimately increased the total nitrogen fixed by the plant.

  8. Response Surface Methodology Study on Magnetite Nanoparticle Formation under Hydrothermal Conditions

    Directory of Open Access Journals (Sweden)

    Naoya Mizutani

    2015-05-01

    Full Text Available In a hydrothermal preparation of crystalline magnetite (Fe3O4 nanoparticles, the influence of the experimental parameters (initial molar ratio of ferrous/ferric ions, initial concentration of ferrous ions, and heating time, and their interactions, on the particle formation was studied using response surface methodology (RSM, based on a statistical design of experiments (DOE. As indices indicating particle formation and crystallization, the variation in the particle diameter and crystallite size with the synthesis conditions was examined. The crystallite size was greatly affected by both the initial ferrous/ ferric ion molar ratio and the heating time, whereas the particle diameter strongly depended on the heating time, and on the interaction between the initial ferrous/ferric ion molar ratio and the initial concentration of ferrous ions. The results from a statistical analysis suggest that the polycrystalline Fe3O4 nanoparticles form via crystal growth and/or thermal aggregation, after nucleation during hydrothermal treatment.

  9. Liquid-liquid phase separation and cluster formation at deposition of metals under inhomogeneous magnetic field

    Science.gov (United States)

    Gorobets, O. Yu; Gorobets, Yu I.; Rospotniuk, V. P.; Grebinaha, V. I.; Kyba, A. A.

    2017-10-01

    The formation and dynamic of expansion and deformation of the liquid-liquid interface of an electrolyte at deposition of metals at the surface of the magnetized steel ball is considered in this paper. The electrochemical processes were investigated in an external magnetic field directed at an arbitrary angle to the force of gravity. These processes are accompanied by the formation of effectively paramagnetic clusters of electrochemical products - magnions. Tyndall effect was used for detection of the presence of magnions near the magnetized steel electrode in a solution. The shape of the interface separating the regions with different concentration of magnions, i.e. different magnetic susceptibilities, was described theoretically based on the equation of hydrostatic equilibrium which takes into account magnetic, hydrostatic and osmotic pressures.

  10. Structural and energetic factors controlling the enantioselectivity of dinucleotide formation under prebiotic conditions

    Czech Academy of Sciences Publication Activity Database

    Šponer, Judit E.; Mládek, Arnošt; Šponer, Jiří

    2013-01-01

    Roč. 15, č. 17 (2013), s. 6235-6242 ISSN 1463-9076 R&D Projects: GA ČR GAP208/10/2302 Grant - others:GA MŠk(CZ) ED1.1.00/02.0068 Program:ED Institutional research plan: CEZ:AV0Z50040702 Institutional support: RVO:68081707 Keywords : APPROXIMATE COULOMB POTENTIALS * PEPTIDE-BOND FORMATION * ZETA VALENCE QUALITY Subject RIV: BO - Biophysics Impact factor: 4.198, year: 2013

  11. Biofilm formation by Salmonella spp. in catfish mucus extract under industrial conditions.

    Science.gov (United States)

    Dhowlaghar, Nitin; De Abrew Abeysundara, Piumi; Nannapaneni, Ramakrishna; Schilling, Mark W; Chang, Sam; Cheng, Wen-Hsing; Sharma, Chander S

    2018-04-01

    The objective of this study was to determine the effect of strain and temperature on the growth and biofilm formation of Salmonella spp. in high and low concentrations of catfish mucus extract on different food-contact surfaces at 22 °C and 10 °C. The second objective of this study was to evaluate the efficacy of disinfectants at recommended concentrations and contact times for removing Salmonella biofilms cells on a stainless steel surface containing catfish mucus extract. Growth and biofilm formation of all Salmonella strains increased with higher concentrations of catfish mucus extract at both 10 °C and 22 °C. In 15 μg/ml of catfish mucus extract inoculated with 3 log CFU/ml, the biofilm levels of Salmonella on stainless steel surface reached to 3.5 log CFU/cm 2 at 10 °C or 5.5 log CFU/cm 2 at 22 °C in 7 days. In 375 μg/ml of catfish mucus extract inoculated with 3 log CFU/ml, the biofilm levels of Salmonella on the stainless steel surface reached 4.5 log CFU/cm 2 at 10 °C and 6.5 log CFU/cm 2 at 22 °C in 7 days. No differences were observed between Salmonella strains tested for biofilm formation in catfish mucus extract on the stainless steel surface. The biofilm formation by Salmonella Blockley (7175) in catfish mucus extract was less (P Salmonella biofilm cells were not detectable on the stainless steel surface after treatment with a mixture of disinfectants but were still present when single compound disinfectants were used. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Electrochemical studies of the film formation on lithium in propylene carbonate solutions under open circuit conditions

    Energy Technology Data Exchange (ETDEWEB)

    Geronov, Y.; Schwager, F.; Muller, R.H.

    1981-04-01

    The nature of protective surface layers formed on lithium in propylene carbonate solutions of LiClO/sub 4/ and LiAsF/sub 6/ at open circuit has been investigated by electrochemical pulse measurements and other techniques. The results are consistent with the fast formation of a compact thin layer of Li/sub 2/O by reaction with residual water. This layer acts as a solid ionic conductor. Slow corrosion processes produce a thicker porous overlayer.

  13. Rons formation under restrictive reperfusion does not affect organ dysfunction early after hemorrhage and trauma.

    Science.gov (United States)

    Zifko, Clara; Kozlov, Andrey V; Postl, Astrid; Redl, Heinz; Bahrami, Soheyl

    2010-10-01

    Reactive oxygen species have been implicated in the pathophysiology of early reperfusion. We aimed to determine 1) reactive oxygen and nitrogen species (RONS) formation in organs of rats and 2) its pathophysiological relevance during a phase of restrictive reperfusion after hemorrhagic/traumatic shock (HTS). Fifty-seven male Sprague-Dawley rats were subjected to a clinically relevant HTS model, featuring laparotomy, bleeding, and a phase of restrictive reperfusion. The RONS scavenger 1-hydroxy-3-carboxy-2,2,5,5-tetramethyl-pyrrolidine hydrochloride (continuous i.v. infusion) and electron paramagnetic resonance spectroscopy were applied for RONS (primarily superoxide and peroxynitrite) detection. Compared with sham-operated animals, the organ-specific distribution of RONS changed during restrictive reperfusion after HTS. Reactive oxygen and nitrogen species formation increased during restrictive reperfusion in red blood cells and ileum only but decreased in the kidney and remained unchanged in other organs. Hemorrhagic traumatic shock followed by restrictive reperfusion resulted in metabolic acidosis, dysfunction of liver and kidney, and increased oxidative burst capacity in circulating cells. Plasma RONS correlated with shock severity and organ dysfunction. However, RONS scavenging neither affected organ dysfunction nor oxidative burst capacity nor myeloperoxidase activity in lung when compared with the shock controls. In summary, a phase of restrictive reperfusion does not increase RONS formation in most organs except in intestine and red blood cells. Moreover, scavenging of RONS does not affect the early organ dysfunction manifested at the end of a phase of restrictive reperfusion.

  14. Paradoxical empowerment of produsers in the context of informational capitalism

    Science.gov (United States)

    Proulx, Serge; Heaton, Lorna; Kwok Choon, Mary Jane; Millette, Mélanie

    2011-04-01

    This article develops a critical perspective on how online contribution practices participate in the creation of economic value under informational capitalism. It discusses the theoretical relevance of the concept of empowerment for exploring online contribution practices. We argue that produsage practices are paradoxical insofar as they can be simultaneously alienating and emancipatory. This theoretical lens allows us to take a fresh look at the collective intelligence of produsers and the role of communities in the collective production of content. We illustrate the fruitfulness of this conceptual approach with two case studies: Facebook and TelaBotanica, a platform for the collaborative production of scientific knowledge.

  15. Nietzsche et les paradoxes de la force

    Directory of Open Access Journals (Sweden)

    Arnaud François

    2011-06-01

    Full Text Available According to this paper, the Nietzschean notion of force actually consists of a number of paradoxes, which I seek to formulate through the philosophical problems they pose. These paradoxes revolve around this fundamental paradox: on the one hand, force is able to rise and fall, but precisely how could such an increase and such a decrease be designed, as far as only what is given once for all can accept quantitative determinations? I come to draw two methods to answer this question (contrariety between two positive forces, reactivity of one force against the other, which suggest two ways of posing the biological and medical problems today, related to the notions of health and disease, in the scope of which Nietzsche has encountered it.

  16. Thermoeconomic diagnosis and entropy generation paradox

    DEFF Research Database (Denmark)

    Sigthorsson, Oskar; Ommen, Torben Schmidt; Elmegaard, Brian

    2017-01-01

    In the entropy generation paradox, the entropy generation number, as a function of heat exchanger effectiveness, counter-intuitively approaches zero in two limits symmetrically from a single maximum. In thermoeconomic diagnosis, namely in the characteristic curve method, the exergy destruction...... to the entropy generation paradox, as a decreased heat exchanger effectiveness (as in the case of an operation anomaly in the component) can counter-intuitively result in decreased exergy destruction rate of the component. Therefore, along with an improper selection of independent variables, the heat exchanger...... increases in case of an operation anomaly in a component. The normalised exergy destruction rate as the dependent variable therefore resolves the relation of the characteristic curve method with the entropy generation paradox....

  17. Formation of Glycerol through Hydrogenation of CO Ice under Prestellar Core Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Fedoseev, G.; Chuang, K.-J.; Qasim, D.; Linnartz, H. [Sackler Laboratory for Astrophysics, Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 RA Leiden (Netherlands); Ioppolo, S. [School of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Dishoeck, E. F. van, E-mail: gfedo@oact.inaf.it [Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 RA Leiden (Netherlands)

    2017-06-10

    Observational studies reveal that complex organic molecules (COMs) can be found in various objects associated with different star formation stages. The identification of COMs in prestellar cores, i.e., cold environments in which thermally induced chemistry can be excluded and radiolysis is limited by cosmic rays and cosmic-ray-induced UV photons, is particularly important as this stage sets up the initial chemical composition from which ultimately stars and planets evolve. Recent laboratory results demonstrate that molecules as complex as glycolaldehyde and ethylene glycol are efficiently formed on icy dust grains via nonenergetic atom addition reactions between accreting H atoms and CO molecules, a process that dominates surface chemistry during the “CO freeze-out stage” in dense cores. In the present study we demonstrate that a similar mechanism results in the formation of the biologically relevant molecule glycerol—HOCH{sub 2}CH(OH)CH{sub 2}OH—a three-carbon-bearing sugar alcohol necessary for the formation of membranes of modern living cells and organelles. Our experimental results are fully consistent with a suggested reaction scheme in which glycerol is formed along a chain of radical–radical and radical–molecule interactions between various reactive intermediates produced upon hydrogenation of CO ice or its hydrogenation products. The tentative identification of the chemically related simple sugar glyceraldehyde—HOCH{sub 2}CH(OH)CHO—is discussed as well. These new laboratory findings indicate that the proposed reaction mechanism holds much potential to form even more complex sugar alcohols and simple sugars.

  18. Formation of Glycerol through Hydrogenation of CO Ice under Prestellar Core Conditions

    Science.gov (United States)

    Fedoseev, G.; Chuang, K.-J.; Ioppolo, S.; Qasim, D.; van Dishoeck, E. F.; Linnartz, H.

    2017-06-01

    Observational studies reveal that complex organic molecules (COMs) can be found in various objects associated with different star formation stages. The identification of COMs in prestellar cores, I.e., cold environments in which thermally induced chemistry can be excluded and radiolysis is limited by cosmic rays and cosmic-ray-induced UV photons, is particularly important as this stage sets up the initial chemical composition from which ultimately stars and planets evolve. Recent laboratory results demonstrate that molecules as complex as glycolaldehyde and ethylene glycol are efficiently formed on icy dust grains via nonenergetic atom addition reactions between accreting H atoms and CO molecules, a process that dominates surface chemistry during the “CO freeze-out stage” in dense cores. In the present study we demonstrate that a similar mechanism results in the formation of the biologically relevant molecule glycerol—HOCH2CH(OH)CH2OH—a three-carbon-bearing sugar alcohol necessary for the formation of membranes of modern living cells and organelles. Our experimental results are fully consistent with a suggested reaction scheme in which glycerol is formed along a chain of radical-radical and radical-molecule interactions between various reactive intermediates produced upon hydrogenation of CO ice or its hydrogenation products. The tentative identification of the chemically related simple sugar glyceraldehyde—HOCH2CH(OH)CHO—is discussed as well. These new laboratory findings indicate that the proposed reaction mechanism holds much potential to form even more complex sugar alcohols and simple sugars.

  19. Effect of a marginal inclination on pattern formation in a binary liquid mixture under thermal stress.

    Science.gov (United States)

    Croccolo, Fabrizio; Scheffold, Frank; Vailati, Alberto

    2013-07-05

    Convective motions in a fluid layer are affected by its orientation with respect to the gravitational field. We investigate the long-term stability of a thermally stressed layer of a binary liquid mixture and show that pattern formation is strongly affected by marginal inclinations as small as a few milliradians. At small Rayleigh numbers, the mass transfer is dominated by the induced large scale shear flow, while at larger Rayleigh numbers, it is dominated by solutal convection. At the transition, the balance between the solutal and shear flows gives rise to drifting columnar flows moving in opposite directions along parallel lanes in a superhighway configuration.

  20. Formation of microspheres under the action of femtosecond laser radiation on titanium samples in hydrocarbons

    Science.gov (United States)

    Kochuev, D. A.; Khorkov, K. S.; Ivashchenko, A. V.; Prokoshev, V. G.; Arakelian, S. M.

    2018-01-01

    This work describes the original method of laser synthesis of microspheres which contain titanium carbide. The formation of microspheres is carried out by the action of femtosecond laser radiation on the surface of titanium in the reaction medium - the ultimate hydrocarbon. The resulting microspheres have a high surface smoothness, a narrow particle size distribution, an average size of 1-3 μm. They can be used in applications of additive engineering, powder metallurgy as the main raw material, or as an alloying additive.

  1. Anisotropy effect of crater formation on single crystal silicon surface under intense pulsed ion beam irradiation

    Science.gov (United States)

    Shen, Jie; Yu, Xiao; Zhang, Jie; Zhong, Haowen; Cui, Xiaojun; Liang, Guoying; Yu, Xiang; Huang, Wanying; Shahid, Ijaz; Zhang, Xiaofu; Yan, Sha; Le, Xiaoyun

    2018-04-01

    Due to the induced extremely fast thermal and dynamic process, Intense Pulsed Ion Beam (IPIB) is widely applied in material processing, which can bring enhanced material performance and surface craters as well. To investigate the craters' formation mechanism, a specific model was built with Finite Element Methods (FEM) to simulate the thermal field on irradiated single crystal silicon. The direct evidence for the existence of the simulated 6-fold rotational symmetric thermal distribution was provided by electron microscope images obtained on single crystal silicon. The correlation of the experiment and simulation is of great importance to understand the interaction between IPIB and materials.

  2. The Paradox of Isochrony in the Evolution of Human Rhythm

    Directory of Open Access Journals (Sweden)

    Andrea Ravignani

    2017-11-01

    Full Text Available Isochrony is crucial to the rhythm of human music. Some neural, behavioral and anatomical traits underlying rhythm perception and production are shared with a broad range of species. These may either have a common evolutionary origin, or have evolved into similar traits under different evolutionary pressures. Other traits underlying rhythm are rare across species, only found in humans and few other animals. Isochrony, or stable periodicity, is common to most human music, but isochronous behaviors are also found in many species. It appears paradoxical that humans are particularly good at producing and perceiving isochronous patterns, although this ability does not conceivably confer any evolutionary advantage to modern humans. This article will attempt to solve this conundrum. To this end, we define the concept of isochrony from the present functional perspective of physiology, cognitive neuroscience, signal processing, and interactive behavior, and review available evidence on isochrony in the signals of humans and other animals. We then attempt to resolve the paradox of isochrony by expanding an evolutionary hypothesis about the function that isochronous behavior may have had in early hominids. Finally, we propose avenues for empirical research to examine this hypothesis and to understand the evolutionary origin of isochrony in general.

  3. Crack initiation and potential hot-spot formation around a cylindrical defect under dynamic compression

    Science.gov (United States)

    Ma, Xiao; Li, Xinguo; Zheng, Xianxu; Li, Kewu; Hu, Qiushi; Li, Jianling

    2017-11-01

    In recent decades, the hot-spot theory of condensed-phase explosives has been a compelling focus of scientific investigation attracting many researchers. The defect in the polymeric binder of the polymer-bonded explosive is called the intergranular defect. In this study, the real polymeric binder was substituted by poly(methyl methacrylate) (PMMA) as it is transparent and has similar thermodynamic properties to some binders. A set of modified split Hopkinson pressure bars equipped with a time-resolved shadowgraph was used to study the process of crack initiation and potential hot-spot formation around a cylindrical defect in PMMA. The new and significant phenomenon that the opening-mode crack emerged earlier than the shearing-mode crack from the cylindrical defect has been published for the first time in this paper. Furthermore, a two-dimensional numerical simulation was performed to show the evolution of both the stress field and the temperature field. The simulation results were in good agreement with the experiment. Finally, the law of potential hot-spot formation is discussed in detail.

  4. In situ diffraction studies of scale formation under Bayer processing conditions

    International Nuclear Information System (INIS)

    Webster, N.; Madsen, I.; Loan, J.

    2009-01-01

    Full text: The Bayer process is used to extract alumina (A I 203) from bauxite ore. The efficiency of the proc severely compromised by the build-up of insoluble species (scale) on the surfaces of mild process equipment, which impedes the material flow through, and heat transfer to, the pr streams [1]. In precipitation areas operating at 60-8 C gibbsite, AI(OHh, scales predominate the spent liquor heaters which typically operate at 150-250 0 C, sodalite and cancrinite-type s aluminosilicate scales are formed (1). An improved understanding of the scale formation mechanism may lead to the development of a practical and economic method for scale prevention. Characterisation of the structure, composition and crystallographic orientation of phases present early stages of formation is crucial for this understanding, making x-ray and neutron diffraction important analytical techniques. In situ synchrotron x-ray diffraction experiments were performed Australian Synchrotron during AI(OHh deposition on mild steel substrates using a purpose built stainless steel flow cell (3). The high resolution data enabled identification of three polymors AI(OH)3 (gibbsite, bayerite and nordtsrandite) in the deposited material, each displaying ori growth along (001). Additional in situ synchrotron XRD experiments, where AI(OH)3 precipitatiol 'seeded' with various iron oxides and oxyhydroxides, have also been performed and some ' results will be discussed. Similar neutron diffraction experiments on Wombat are planned investigations of seeded aluminosilicate precipitation at 150-250 0 C using an Inconel hydrothermal cell.

  5. Deactivating Carbon Formation on a Ni/Al2O3 Catalyst under Methanation Conditions

    DEFF Research Database (Denmark)

    Olesen, Sine Ellemann; Andersson, Klas J.; Damsgaard, Christian Danvad

    2017-01-01

    The carbon formation causing deactivation during CO methanation was studied for a Ni/Al2O3 catalyst. Sulfur-free methanation at low temperature (573 K) for various lengths of time was followed by temperature-programmed hydrogenation (TPH) providing information on carbon types involved in the deac......The carbon formation causing deactivation during CO methanation was studied for a Ni/Al2O3 catalyst. Sulfur-free methanation at low temperature (573 K) for various lengths of time was followed by temperature-programmed hydrogenation (TPH) providing information on carbon types involved...... in the deactivation of the catalyst.Three main carbon hydrogenation peaks were evident from TPHs following methanation: ∼460, ∼650, and ∼775 K. It is suggested that the ∼460 K TPH peak was composed of two peaks: a surface carbide peak at 445–460 K, and a peak due to carbon dissolved into the nickel at 485 K based...... on CO and CH4 adsorption measurements and XRD analysis. The 650 and 775 K temperature peaks are assigned to polymerized carbon structures and the ∼775K peak was found to be the primary cause of deactivation as judged by a linear correlation between its amount and the degree of catalyst deactivation...

  6. Dynamics of Plug Formation in a Circular Cylinder Under Low Bond Number Conditions: Experiment and Simulation

    Science.gov (United States)

    Hallaby, Ghazi; Kizito, John P.

    2016-08-01

    The goal of the current study is to investigate the dynamics of two phase interface under a low Bond number condition. Silicone oil is injected into a cylinder under a Bond number of about 0.47 via a side tube forming a T-junction with the former. The time evolution of the interface of silicon oil in a cylinder is captured using a high speed camera. The volume at which the plug is formed is then determined using an image processing tool to analyze the captured images. A numerical simulation is carried out where fluid is injected into a cylinder, under a less than unity Bond number condition, via a side tube. Numerical and experimental results are then compared.

  7. Formation and Characterization of TiO2/CNT Nanomaterials Dried under Supergravity Conditions

    Directory of Open Access Journals (Sweden)

    Minerva Vargas

    2009-01-01

    Full Text Available The elaboration of bilayer TiO2/CNT films dried under terrestrial gravity conditions (g and on a centrifuge with 1.3g and 7g is reported. The changes in microstructure and thickness of these coatings under supergravity environment cause a red-shift tendency in the optical properties at increasing values of acceleration. Experiments of a drop under enhanced gravity force in the range of 3.7 < Bo (bond number < 51.5 suggest the incomplete elimination of surfactant-water molecules in the TiO2/CNT bilayer film. Increasing acceleration up to 14g will widen the optical differences found, proving the layer-by-layer solution-chemical method in combination with these drying protocols, an alternative to produce thickness-sensitive solar-selective absorbing coatings.

  8. Resolving the paradox of suboptimal choice.

    Science.gov (United States)

    Zentall, Thomas R

    2016-01-01

    When humans engage in commercial (totally probabilistic) gambling they are making suboptimal choices because the return is generally less than the investment. This review (a) examines the literature on pigeon suboptimal choice, (b) describes the conditions under which it occurs, (c) identifies the mechanisms that appear to be responsible for the effect, and (d) suggests that similar processes may be able to account for analogous suboptimal choice when humans engage in commercial gambling. Pigeons show suboptimal choice when they choose between 1 alternative that 20% of the time provides them with a signal that they will always get fed or 80% of the time with a signal that they will not get fed (overall 20% reinforcement) and a second alternative that 100% of the time provides them with a signal that they will get fed 50% of the time (overall 50% reinforcement). The pigeons' strong preference for the suboptimal choice was investigated in a series of experiments that found the preference for the suboptimal alternative was determined by the value of the signal that predicted reinforcement, rather its frequency and that the frequency of the signal that predicted nonreinforcement had little effect on the suboptimal choice. Paradoxically, this account makes the prediction that pigeons will be indifferent between an alternative that 50% of the time provides a fully predictive stimulus for reinforcement and an alternative that 100% of the time provides a fully predictive stimulus for reinforcement. The similarities and differences of this suboptimal choice task to human gambling are discussed. (c) 2016 APA, all rights reserved).

  9. Standard format and content of financial assurance mechanisms required for decommissioning under 10 CFR parts 30, 40, 70, and 72

    International Nuclear Information System (INIS)

    1990-01-01

    The Nuclear Regulatory Commission (NRC) has established technical and financial regulations for decommissioning licensed nuclear facilities (53 FR 24018, June 27, 1988). The regulations address decommissioning planning needs, timing, funding methods, and environmental review requirements for public and private facilities holding licenses under 10 CFR Parts 30, 40, 50, 70, and 72, with the exception of uranium mills. The intent of the regulations is to ensure that the decommissioning of all licensed facilities will be accomplished in a safe and timely manner and that licensees will provide adequate funds to cover all costs associated with decommissioning. The purpose of this regulatory guide, ''Standard Format and Content of Financial Assurance Mechanisms Required for Decommissioning Under 10 CFR Parts 30, 40, 70, and 72,'' is to provide guidance acceptable to the NRC staff on the information to be provided for establishing financial assurance for decommissioning and to establish a standard format for presenting the information. Use of the standard format will (1) help ensure that the financial instruments contain the information required by 10 CFR Parts 30, 40, 70, and 72, (2) aid the applicant and NRC staff in ensuring that the information is complete, and (3) help persons reading the financial instruments to locate information. 5 refs., 13 figs

  10. The thermodynamics of molecular cloud fragmentation : Star formation under non-Milky Way conditions

    NARCIS (Netherlands)

    Hocuk, S.; Spaans, M.

    Context. Properties of candidate stars, forming out of molecular clouds, depend on the ambient conditions of the parent cloud. We present a series of 2D and 3D simulations of fragmentation of molecular clouds in starburst regions, as well as of clouds under conditions in dwarf galaxies, leading to

  11. Effective Strategy Formation Models for Inventory Management under the Conditions of Uncertainty

    Science.gov (United States)

    Kosorukov, Oleg Anatolyevich; Sviridova, Olga Alexandrovna

    2015-01-01

    The article deals with the problem of modeling the commodity flows management of a trading company under the conditions of uncertain demand and long supply. The Author presents an analysis of modifications of diversified inventory management system with random demand, for which one can find the optimal inventory control strategies, including those…

  12. Monitoring of biofilm formation and activity in drinking water distribution networks under oligotrophic conditions

    DEFF Research Database (Denmark)

    Boe-Hansen, Rasmus; Martiny, Adam Camillo; Arvin, Erik

    2003-01-01

    In this study, the construction a model distribution system suitable for studies of attached and suspended microbial activity in drinking water under controlled circumstances is outlined. The model system consisted of two loops connected in series with a total of 140 biofilm sampling points...

  13. Thin block copolymer films : film formation and corrugation under the AFM tip

    NARCIS (Netherlands)

    Maas, J.H.; Cohen Stuart, M.A.; Fleer, G.J.

    2000-01-01

    The tip of an atomic force microscope was used to induce nanoscale ordering in thin films of polystyrene-poly(4-vinyl pyridine) block copolymers under low force. The AFM tip produces rims on a mesoscopic scale oriented perpendicularly to the scanning direction. A wide range of molecular weights of

  14. Growth of silicone-immobilized bacteria on polycarbonate membrane filters, a technique to study microcolony formation under anaerobic conditions

    DEFF Research Database (Denmark)

    Højberg, Ole; Binnerup, S. J.; Sørensen, Jan

    1997-01-01

    A technique was developed to study microcolony formation by silicone- immobilized bacteria on polycarbonate membrane filters under anaerobic conditions. A sudden shift to anaerobiosis was obtained by submerging the filters in medium which was depleted for oxygen by a pure culture of bacteria....... The technique was used to demonstrate that preinduction of nitrate reductase under low-oxygen conditions was necessary for nonfermenting, nitrate-respiring bacteria, e.g., Pseudomonas spp., to cope with a sudden lack of oxygen. In contrast, nitrate-respiring, fermenting bacteria, e.g., Bacillus and Escherichia...... spp, formed microcolonies under anaerobic conditions with or without the presence of nitrate and irrespective of aerobic or anaerobic preculture conditions....

  15. Formation of Biogenic Amines in Chicken Meat Stored under Modified Atmosphere

    Directory of Open Access Journals (Sweden)

    Leo Gallas

    2010-01-01

    Full Text Available The aim of the study was to investigate the effects of two modified atmospheres with a different combination of gases on selected groups of microorganisms and on concentrations of biogenic amines (BAs in samples of poultry breast muscle. The samples were packaged under modified atmosphere A (75% O2 a 25% CO2 or B (75% N2 and 25% CO2 and stored at temperatures from +2 to +4 °C for 14 days. During the storage period, O2 concentrations in modified atmosphere A (MA A decreased from the initial 74.8 ± 0.3% to 55.9 ± 6.6% at the end of the storage period. In all samples, counts of psychrotrophic bacteria counts, Brochothrix thermosphacta, lactic acid bacteria and coliform microorganism were determined. The tests were made on the packaging day, and then after three, nine and fourteen days of storage. At the end of the storage period, higher numbers of psychrotrophic bacteria (6.5 ± 0.7 log10 cfu g-1, Brochothrix thermosphacta (4.8 ± 0.3 log10 cfu g-1 and lactic acid bacteria (1.7 ± 0.4 log10 cfu g-1 were found on samples packaged under MA A. Samples packaged under modified atmosphere B on the other hand contained higher numbers of coliform bacteria (4.1 ± 0.6 log10 cfu g-1 at the end of the storage period. In addition to microbiological indicators, concentrations of biogenic amines (putrescine, cadaverine, histamine, tyramine, spermine, spermidine and β-phenylethylamine were also determined. In fresh samples and after three days of storage, only spermine and spermidine were found. After 9 and 14 days, also other BAs were detected. The biogenic amine totals at the end of the storage period was 60.0 ± 13.2 mg kg-1 in samples packaged under MA A and 129.0 ± 41.3 mg kg-1 in samples packaged under MA B. The most abundantly represented biogenic amines in samples packaged under MA A were putrescine and spermine (49.7 and 24.8%, respectively, at the end of the storage period, and putrescine and cadaverine in samples packaged under MA B (47.0 and 32

  16. A Model of Digital Payment Infrastructure Formation and Development Under a Emerging SEPA Regime

    DEFF Research Database (Denmark)

    Staykova, Kalina; Damsgaard, Jan

    The Single Euro Payments Area (SEPA) is probably the most ambitious self-regulatory project aimed at creating a single integrated European digital payments market since the introduction of the Euro. SEPA aims to make EU more innovative and competitive. When considering the SEPA initiative...... and combining it with the disruptive and innovative nature the mobile phone permeates, the result is a market that is rapidly transforming from well-established into a state of flux. We build a model to understand and explain this transformation of the digital payment infrastructure. The model captures...... the formation and development of digital payment infrastructure with a particular emphasis on the regulator´s perspective. It consists of four stages characterized by slow incremental change following by short rapid bursts of discontinuity. Each stage is portrayed by its evolutionary dynamics, the nature...

  17. Surface modification and droplet formation of tungsten under hot plasma irradiation at the GOL-3

    Science.gov (United States)

    Arzhannikov, A. V.; Bataev, V. A.; Bataev, I. A.; Burdakov, A. V.; Ivanov, I. A.; Ivantsivsky, M. V.; Kuklin, K. N.; Mekler, K. I.; Rovenskikh, A. F.; Polosatkin, S. V.; Postupaev, V. V.; Sinitsky, S. L.; Shoshin, A. A.

    2013-07-01

    The paper presents experimental investigations of tungsten surface modification after plasma loads at the multimirror trap GOL-3. Energy loads on tungsten surface varied from 2 up to 4 MJ/m2 per shot with sets from 1 to 9 repetitive irradiations that corresponds to loads higher than tungsten melting threshold and is close to ITER giant ELM loads. Targets surface modification and transverse microsections after irradiation was studied by optical microscopy, SEM and hardness tester. Formation on tungsten surface of three different crack networks with typical cell sizes of 1000, 10 and 0.3 μm and bubbles are identified. The network of large cracks extend perpendicularly to the irradiated sample surface to a depth of 50-350 μm. Erosion depth depends on energy loads - rises from 20 to 200 μm at 2 and 4 MJ/m2 correspondingly. Cracking, development of tungsten surface morphology and droplets splashing are discussed.

  18. Surface modification and droplet formation of tungsten under hot plasma irradiation at the GOL-3

    International Nuclear Information System (INIS)

    Arzhannikov, A.V.; Bataev, V.A.; Bataev, I.A.; Burdakov, A.V.; Ivanov, I.A.; Ivantsivsky, M.V.; Kuklin, K.N.; Mekler, K.I.; Rovenskikh, A.F.; Polosatkin, S.V.; Postupaev, V.V.; Sinitsky, S.L.; Shoshin, A.A.

    2013-01-01

    The paper presents experimental investigations of tungsten surface modification after plasma loads at the multimirror trap GOL-3. Energy loads on tungsten surface varied from 2 up to 4 MJ/m 2 per shot with sets from 1 to 9 repetitive irradiations that corresponds to loads higher than tungsten melting threshold and is close to ITER giant ELM loads. Targets surface modification and transverse microsections after irradiation was studied by optical microscopy, SEM and hardness tester. Formation on tungsten surface of three different crack networks with typical cell sizes of 1000, 10 and 0.3 μm and bubbles are identified. The network of large cracks extend perpendicularly to the irradiated sample surface to a depth of 50–350 μm. Erosion depth depends on energy loads – rises from 20 to 200 μm at 2 and 4 MJ/m 2 correspondingly. Cracking, development of tungsten surface morphology and droplets splashing are discussed

  19. Microstructure formation features of the V-4Ti-4Cr alloy under severe plastic deformations

    International Nuclear Information System (INIS)

    Ditenberg, I.; Tyumentsev, A.; Pinzhin, Y.P.; Potapenko, M.M.; Korotaev, A.D.; Chernov, V.M.

    2007-01-01

    Full text of publication follows: Transmission electron microscopy was used to examine the microstructure formed under severe deformations (ε≥93%) in V-4Ti-4Cr alloys rolled at room temperature. Micro-band nano-structured states and high-energy defect substructures have been detected that feature a high curvature (up to x ij ≅ 20 deg. μm -1 ) of the crystal lattice, a high density (δΘ/δr ≥ 20 deg. μm -1 ) of partial disclinations at the micro-band boundaries, and local internal stresses reaching σ ≅ E/30 (E being Young's modulus). It has been shown that important features of the micro-band structure are the prevailing reorientation of the micro-bands around type directions and the high density of large angle boundaries with reorientation vectors Θ = (50-60) deg. . It has been supposed that these features result from the plastic deformation and reorientation of the crystal lattice through mechanisms of local martensitic type reversible transformations (direct plus reverse transformations accompanied by a change of the reverse transformation system) in fields of high local stresses. The most important factors involved in the new deformation mechanism and the prerequisites to its realization are discussed, namely, the degree of phase instability of the material, the intensity of local internal stresses, and the possibility of the relaxation of these stresses by ordinary plastic flow mechanisms. Theoretical analysis of the atomic mechanisms and distortions of the above transformations has shown that the most important features of the carriers of this deformation mode are the absence of any effective obstacles, under severe deformations included, and the possibility of the high-defect structural states formed under these conditions to intensely relax. It is supposed that the combined effect of these two factors underlies the phenomenon of ultrahigh technological plasticity of the alloys under investigation: very high (practically unlimited) plastic

  20. Evaluating paradox walnut rootstocks for resistance to Armillaria root disease

    Science.gov (United States)

    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...

  1. Reversal of a Suspected Paradoxical Reaction to Zopiclone with Flumazenil

    DEFF Research Database (Denmark)

    Jordahn, Zarah; Andersen, Cheme; Aaberg, Anne Marie Roust

    2016-01-01

    ), the patient became agitated and was confused, a possible paradoxical reaction to benzodiazepines. These symptoms were immediately resolved after treatment with flumazenil, usually used to reverse the adverse effects of benzodiazepines or NBRAs and to reverse paradoxical reactions to benzodiazepines. This case...... indicates that zopiclone induced behavioral changes resembling a paradoxical reaction to benzodiazepines and these symptoms may be treated with flumazenil....

  2. Formation and deposition of platinum nanoparticles under boiling water reactor conditions

    Science.gov (United States)

    Grundler, Pascal V.; Veleva, Lyubomira; Ritter, Stefan

    2017-10-01

    Stress corrosion cracking (SCC) is a well-known degradation mechanism for components of boiling water reactors (BWRs). Therefore the mitigation of SCC is important for ensuring the integrity of the reactor system. Noble metal chemical application (NMCA) has been developed by General Electric to mitigate SCC and reduce the negative side-effects of hydrogen water chemistry used initially for SCC mitigation. NMCA is now widely applied as an online process (OLNC) during power operation. However, the understanding of the parameters that control the formation and deposition of the noble metal (Pt) particles in a BWR was still incomplete. To fill this knowledge gap, systematic studies on the formation and deposition behaviour of Pt particles in simulated and real BWR environment were performed in the framework of a research project at PSI. The present paper summarizes the most important findings. Experiments in a sophisticated high-temperature water loop revealed that the flow conditions, water chemistry, the Pt injection rate, and the pre-conditioning of the stainless steel surfaces have an impact on the Pt deposition behaviour. Slower Pt injection rates and stoichiometric excess of H2 over O2 produce smaller particles, which may increase the efficiency of the OLNC technique in mitigating SCC. Surfaces with a well-developed oxide layer retain more Pt particles. Furthermore, the pre- and post-OLNC exposure times play an important role for the Pt deposition on specimens exposed at the KKL power plant. Redistribution of Pt in the plant takes place, but most of the Pt apparently does not redeposit on the steel surfaces in the reactor system. Comparison of lab and plant results also demonstrated that plant OLNC applications can be simulated reasonably well on the lab scale.

  3. The Faint Young Sun Paradox: A Simplified Thermodynamic Approach

    Directory of Open Access Journals (Sweden)

    F. Angulo-Brown

    2012-01-01

    Full Text Available Classical models of the Sun suggest that the energy output in the early stage of its evolution was 30 percent less than today. In this context, radiative balance alone between The Sun and the Earth was not sufficient to explain the early presence of liquid water on Earth’s surface. This difficulty is called the faint young Sun paradox. Many proposals have been published to solve this paradox. In the present work, we propose an oversimplified finite-time thermodynamic approach that describes the air convective cells in the Earth atmosphere. This model introduces two atmospheric modes of thermodynamic performance: a first mode consisting in the maximization of the power output of the convective cells (maximum power regime and a second mode that consists in maximizing a functional representing a good trade-off between power output and entropy production (the ecological regime. Within the assumptions of this oversimplified model, we present different scenarios of albedo and greenhouse effects that seem realistic to preserve liquid water on the Earth in the early stage of formation.

  4. Solving Strategic Paradoxes through Organizational Ambidexterity - A Foray into the Literature -

    Directory of Open Access Journals (Sweden)

    Ogrean Claudia

    2016-08-01

    Full Text Available In a world of unprecedented (diachronic and synchronic complexities like ours, firms are forced to deal with an increasing number of organizational paradoxes that challenge their strategic choices. Under these circumstances, ambidexterity could become a (dynamic core competence for firms, making the ambidextrous organization an imperative for businesses more than ever before. The paper aims to explore, based on an integrative approach, the most relevant literature on the interdependencies between the two topics (strategic paradoxes and organizational ambidexterity, in order to identify the most important thesis, arguments and solutions that support the ambidextrous organization, four decades after its first introduction into the academic literature (Duncan, 1976.

  5. A Case of Tuberculous Meningitis with Paradoxical Response in a 14-Year-Old Boy

    Directory of Open Access Journals (Sweden)

    Murat Özer

    2016-01-01

    Full Text Available A clinical or radiological worsening of already existing lesions or an emergence of new lesions after beginning treatment in patients with tuberculosis (TB is referred to as the paradoxical response. This has aroused suspicion regarding the accuracy of diagnosis, the possibilities of treatment failure, or the presence of another underlying disease, and thus it is an important topic for clinicians to understand. In this article, the development of a paradox reaction in a 14-year-old male patient diagnosed with and treated for tuberculosis meningitis is reported. This pediatric patient with a healthy immune system is treated with steroids successfully and reported to elucidate the importance of managing the paradox of TB progression in spite of the appropriate anti-TB medications.

  6. Mechanisms underlying reductant-induced reactive oxygen species formation by anticancer copper(II) compounds

    OpenAIRE

    Kowol, Christian R.; Heffeter, Petra; Miklos, Walter; Gille, Lars; Trondl, Robert; Cappellacci, Loredana; Berger, Walter; Keppler, Bernhard K.

    2011-01-01

    Intracellular generation of reactive oxygen species (ROS) via thiol-mediated reduction of copper(II) to copper(I) has been assumed as the major mechanism underlying the anticancer activity of copper(II) complexes. The aim of this study was to compare the anticancer potential of copper(II) complexes of Triapine (3-amino-pyridine-2-carboxaldehyde thiosemicarbazone; currently in phase II clinical trials) and its terminally dimethylated derivative with that of 2-formylpyridine thiosemicarbazone a...

  7. STRATEGIC ENERGY SECURITY OUTLOOK FORMATION OF UKRAINE UNDER EUROPEAN INTEGRATION PROCESS

    OpenAIRE

    Voynarenko, Mykhaylo Petrovych; Mykolyuk, Oksana Anatoliyivna

    2017-01-01

    Urgency of the research. Energy security affects the competitiveness of national production in the world markets and the competitiveness of the national economy under globalization. Target setting. Implementation of existing potential requires a deep reform of the regulatory and legal framework and the requirements of international agreements in full. Actual scientific researches and issues analysis. Some aspects of energy security in terms of European integration exploring Barannik V., V. Ge...

  8. Formation and dimensions of marketing culture under the contemporary conditions of competition

    OpenAIRE

    Urbanskienė, Rūta; Žostautienė, Daiva

    2002-01-01

    Companies seeking to retain their position in the market are in search for competitive advantages. Alas, under contemporary conditions only traditional advantages are not sufficient; such as price, nicer or more convenient package, as competitors rapidly emulate such advantages. The advantages that would not be immediately emulated and the consumer could evaluate them as an exclusive attribute of the company’s activities are necessary nowadays. Such advantages may be provided by marketing cul...

  9. The Glocal Teacher: The Paradox Agency of Teaching in a Glocalised World

    Science.gov (United States)

    Trippestad, Tom Are

    2016-01-01

    The article presents the concept of rhetorical agency to understand and analyse the parallel and paradoxical agencies teachers are offered, and limited by, under discourses of globalisation within education. The paper identifies typical arguments, reactions, narratives and metaphors of globalisation. It discusses some of the consequences these…

  10. The Mexican Health Paradox: Expanding the Explanatory Power of the Acculturation Construct

    Science.gov (United States)

    Horevitz, Elizabeth; Organista, Kurt C.

    2013-01-01

    The Mexican health paradox refers to initially favorable health and mental health outcomes among recent Mexican immigrants to the United States. The subsequent rapid decline in Mexican health outcomes has been attributed to the process of acculturation to U.S. culture. However, the construct of acculturation has come under significant criticism…

  11. A Paradox in Radiation Heat Transfer

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 4. A Paradox in Radiation Heat Transfer. J Srinivasan. Classroom Volume 12 Issue 4 April 2007 pp 85-91. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/012/04/0085-0091. Keywords. Radiation ...

  12. Micro-Macro Paradoxes of Entrepreneurship

    DEFF Research Database (Denmark)

    Søgaard, Villy

    2008-01-01

    Artiklen tager afsæt i det såkaldte micro-macro paradox fra Aids-Efficiency litteraturen og argumenterer for, at en tilsvarende problemstilling bør inddrages i vurderingen af f.eks. de beskæftigelsesmæssige konsekvenser af entrepreneuriel virksomhed. Den påviser også i en gennemgang af litteratur...

  13. Art's Pedagogical Paradox

    Science.gov (United States)

    Kalin, Nadine M.

    2014-01-01

    This article contributes to conversations concerning art education futures through engaging alternative relations between art, education, and democracy that mobilize education as art projects associated with the "pedagogical turn" as sites of liminality and paradox. An analysis of the art project, Pedagogical Factory, is used to outline…

  14. Gender paradoxes and agricultural monopoly in Nigeria ...

    African Journals Online (AJOL)

    This is essentially paradoxical. While policies and scholarly attempts have focused the roles of mechanization, processing, subsidies, redistribution, export and, recently, climate change, the role of gender relative to sustainability, social justice, exclusion/inclusion and agricultural optimization for food security remains largely ...

  15. The Neuroethological Paradox of Animal Consciousness.

    Science.gov (United States)

    Gutfreund, Yoram

    2017-04-01

    The more advanced our understanding of the brain of an animal is, the less likely that this animal is a conscious being. This provocative logical paradox is explained and analyzed, leading to the conclusion that to advance understanding of animal consciousness it is necessary to resolve first how our consciousness is produced by our brain. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Understanding Kinetic Energy paradox in Quantum Mechanics

    OpenAIRE

    Kornyushin, Yuri

    2008-01-01

    A concept of Kinetic Energy in Quantum Mechanics is analyzed. Kinetic Energy is not zero in many cases where there are no motion and flux. This paradox can be understood, using expansion of the wave function in Fourier integral, that is on the basis of virtual plane waves.

  17. The Paradox of the Excluded Child

    Science.gov (United States)

    Haynes, Bruce

    2005-01-01

    A paradox seems to exist where a child, of compulsory schooling age, is excluded from a school. The practice of exclusion has evolved over the almost two centuries of compulsory schooling. Abolition of corporal punishment in Western Australia and elsewhere has tended to focus attention on exclusion and the grounds justifying such action by school…

  18. The Einstein-Podolsky-Rosen paradox

    International Nuclear Information System (INIS)

    Roy, S.M.

    1980-01-01

    The celebrated arguments of Einstein, Podolsky and Rosen claiming that quantum mechanics cannot be a complete theory are reviewed. Recent research climaxed by Bell's theorem shows that Einstein's locality or ''no telepathy'' postulate conflicts with quantum theory. It adds a new dimension to the paradox by catapulting the problem from the domain of metaphysics into that of experimental physics. (auth.)

  19. Inducible defences and the paradox of enrichment.

    NARCIS (Netherlands)

    Vos, M.; Kooi, B.W.; Mooij, W.M.; DeAngelis, D.L.

    2004-01-01

    In order to evaluate the effects of inducible defences on community stability and persistence, we analyzed models of bitrophic and tritrophic food chains that incorporate consumer-induced polymorphisms. These models predict that intraspecific heterogeneity in defence levels resolves the paradox of

  20. Inducible defences and the paradox of enrichment

    NARCIS (Netherlands)

    Vos, M.; Kooi, B.W.; DeAngelis, D.L.; Mooij, W.M.

    2004-01-01

    In order to evaluate the effects of inducible defences on community stability and persistence, we analyzed models of bitrophic and tritrophic food chains that incorporate consumer-induced polymorphisms. These models predict that intra-specific heterogeneity in defence levels resolves the paradox of

  1. On a paradox of probability theory

    International Nuclear Information System (INIS)

    Stuart, C.I.J.M.

    1989-01-01

    Costa de Beauregard's proposal concerning physical retrocausality has been shown to fail on two crucial points. However, it is argued that his proposal still merits serious attention. The argument arises from showing that his proposal reveals a paradox involving relations between conditional probabilities, statistical correlations and reciprocal causalities of the type exhibited by cooperative dynamics in physical systems. 4 refs. (Author)

  2. Biofuel Mandating and the Green Paradox

    NARCIS (Netherlands)

    Okullo, Samuel; Reynes, F.; Hofkes, M.

    2016-01-01

    The theory on the green paradox has focused primarily on the consumption of a clean substitute produced using a static technology. In reality, we observe the gradual accumulation of the clean substitute’s capacity, suggesting that supply decisions for the clean substitute and finite carbon resource

  3. An alternative resolution to the Mansuripur paradox

    Science.gov (United States)

    Redfern, Francis

    2016-04-01

    In 2013 an article published online by the journal Science declared that the paradox proposed by Masud Mansuripur was resolved. This paradox concerns a point charge-Amperian magnetic dipole system as seen in a frame of reference where they are at rest and one in which they are moving. In the latter frame an electric dipole appears on the magnetic dipole. A torque is then exerted upon the electric dipole by the point charge, a torque that is not observed in the at-rest frame. Mansuripur points out this violates the relativity principle and suggests the Lorentz force responsible for the torque be replaced by the Einstein-Laub force. The resolution of the paradox reported by Science, based on numerous papers in the physics literature, preserves the Lorentz force but depends on the concept of hidden momentum. Here I propose a different resolution based on the overlooked fact that the charge-magnetic dipole system contains linear and angular electromagnetic field momentum. The time rate of change of the field angular-momentum in the frame through which the system is moving cancels that due to the charge-electric dipole interaction. From this point of view hidden momentum is not needed in the resolution of the paradox.

  4. Quantum information paradox: Real or fictitious?

    Indian Academy of Sciences (India)

    https://www.ias.ac.in/article/fulltext/pram/073/03/0615-0622. Keywords. Quantum information paradox; black hole; eternally collapsing object. Abstract. One of the outstanding puzzles of theoretical physics is whether quantum information indeed gets lost in the case of black hole (BH) evaporation or accretion. Let us recall ...

  5. "Peasants in Cities": Paradox or Conceptual Muddle?

    Science.gov (United States)

    Isaac, Barry L.

    1974-01-01

    Written in response to T. G. McGee's recent discussion of the "peasants in cities" paradox (see EJ080361), this article argues that a modified version of Eric Wolf's definition of "peasants" is the most useful one currently available. (Author/KM)

  6. Quantum Zeno and anti-Zeno paradoxes

    Indian Academy of Sciences (India)

    Continuous observation of a time independent projection operator is known to prevent change of state (the quantum Zeno paradox). We discuss the recent result that ... Author Affiliations. S M Roy1. Department of Theoretical Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India ...

  7. Zeno's paradox in quantum cellular automata

    International Nuclear Information System (INIS)

    Groessing, G.; Zeilinger, A.

    1991-01-01

    The effect of Zeno's paradox in quantum theory is demonstrated with the aid of quantum mechanical cellular automata. It is shown that the degree of non-unitarity of the cellular automaton evolution and the frequency of consecutive measurements of cellular automaton states are operationally indistinguishable. (orig.)

  8. Joblessness in the Arctic: The Alaskan Paradox.

    Science.gov (United States)

    Bland, Laurel L.

    Alaska is in the paradoxical position of having more jobs available than people, and at the same time maintaining one of the highest unemployment rates in the nation. This report discusses the nature and skills of the unemployed and underemployed, and presents tables of demographic information. While a fair percentage of Alaskan native youth…

  9. Jack London: The Paradox of Individualism.

    Science.gov (United States)

    Deane, Paul

    1968-01-01

    Because of their interest in naturalism and socialism, critics often overlook the major intellectual conflict in Jack London's work: the paradox of individualism. London regards society as affecting the individual in two ways: it either promotes individuality or it demands a conformity that undermines individualism. When society fails Buck in…

  10. Micro-Macro Paradoxes of Entrepreneurship

    DEFF Research Database (Denmark)

    Søgaard, Villy

    2008-01-01

    Artiklen tager afsæt i det såkaldte micro-macro paradox fra Aids-Efficiency litteraturen og argumenterer for, at en tilsvarende problemstilling bør inddrages i vurderingen af f.eks. de beskæftigelsesmæssige konsekvenser af entrepreneuriel virksomhed. Den påviser også i en gennemgang af litteraturen...

  11. Formation and coalescence of nanobubbles under controlled gas concentration and species

    Science.gov (United States)

    Li, Chenliang; Zhang, A.-Man; Wang, Shiping; Cui, Pu

    2018-01-01

    Using molecular dynamics simulations, the effects of gas concentration and species on the coalescence and growth of nanobubbles were systematically investigated. With increasing gas concentration, not only surface nanobubbles but also bulk nanobubbles are formed. The bulk nanobubble in water is less explored so far. Here, its coalescence, stability, movement trajectory and velocity are discussed. A comparison of the motion and coalescence of the bulk nanobubble to the surface nanobubble, directly demonstrates that the three-phase contact line plays a crucial role for surface nanobubble stability. Compared with the bubble size, the distance between surface nanobubbles is a more important factor to decide the merging order among three nanobubbles. The study also shows that three factors including the oversaturated gas concentration, the distance between surface nanobubbles, and the stronger solid-gas interactions influence the formation of the gas-enrichment layer at the solid-liquid interface. The result has an important significance to enhancing the boundary slip due to the presence of nanobubbles.

  12. Shock Formation by Plasma Filaments of Microwave Discharge under Atmospheric Pressure

    International Nuclear Information System (INIS)

    Takahashi, Masayuki; Ohnishi, Naofumi

    2016-01-01

    A one-dimensional compressible fluid calculation was coupled with a finite- difference time-domain code and a particle-in-cell code with collision to reproduce propagation of electromagnetic wave, ionization process of plasma, and shock wave formation in atmospheric microwave discharge. Plasma filaments are driven toward the microwave source at 1 atm, and the distance between each filament is one-fifth of the wavelength of the incident microwave. The strong shock wave is generated due to the high plasma density at the atmospheric pressure. A simple analysis of the microwave propagation into the plasma shows that cut-off density of the microwave becomes smaller with the pressure decrease in a collisional plasma. At the lower pressure, the smaller density plasma is obtained with a diffusive pattern because of the smaller cut-off density and the larger diffusion effect. In contrast with the 1-atm case, the weak shock wave is generated at a rarefied condition, which lowers performance of microwave thruster. (paper)

  13. Effect of soil invertebrates on the formation of humic substances under laboratory conditions

    Science.gov (United States)

    Frouz, J.; Li, X.; Brune, A.; Pizl, V.; Abakumov, E. V.

    2011-08-01

    The complete polymerization of phenols and proteins (one of the processes involved in the formation of humic substances) was explained. It was shown that fly ( Bibio marci) larvae and earthworms ( Aporrectodea caliginosa) participate in the complete polymerization of phenols and proteins. In a laboratory experiment, invertebrates participated in the degradation of organic matter and the synthesis of humic substances, which was proved in experiments with 14C-labeled phenols and proteins. The same organic substances (phenols and proteins) without the impact of invertebrates were used as the control substances. The distributions of the 14C isotope in alkaline extracts separated by solubility in acids (humic and fulvic acids) was compared to those of the control substances. The portion of the 14C isotope in the humic acids in the excrements of Bibio marci was higher than that in the control substances. The content of 14C-labeled humic substances in the excrements of the earthworm Aporrectodea caliginosa exceeded the control values only in the experiment with proteins. When clay material was added to the organic substances, the portion of the 14C isotope in the humic acids increased in both experiments with phenols and proteins. When these substrates passed through the digestive tracts of the invertebrates, the polymerization of organic substances and the inclusion of proteins and phenols into humic acids occurred.

  14. Jet formation in spallation of metal film from substrate under action of femtosecond laser pulse

    International Nuclear Information System (INIS)

    Inogamov, N. A.; Zhakhovskii, V. V.; Khokhlov, V. A.

    2015-01-01

    It is well known that during ablation by an ultrashort laser pulse, the main contribution to ablation of the substance is determined not by evaporation, but by the thermomechanical spallation of the substance. For identical metals and pulse parameters, the type of spallation is determined by film thickness d f . An important gauge is metal heating depth d T at the two-temperature stage, at which electron temperature is higher than ion temperature. We compare cases with d f < d T (thin film) and d f ≫ d T (bulk target). Radius R L of the spot of heating by an optical laser is the next (after d f ) important geometrical parameter. The morphology of film bulging in cases where d f < d T on the substrate (blistering) changes upon a change in radius R L in the range from diffraction limit R L ∼ λ to high values of R L ≫ λ, where λ ∼ 1 μm is the wavelength of optical laser radiation. When d f < d T , R L ∼ λ, and F abs > F m , gold film deposited on the glass target acquires a cupola-shaped blister with a miniature frozen nanojet in the form of a tip on the circular top of the cupola (F abs and F m are the absorbed energy and the melting threshold of the film per unit surface area of the film). A new physical mechanism leading to the formation of the nanojet is proposed

  15. Still under the ancestors' shadow? Ancestor worship and family formation in contemporary China

    Directory of Open Access Journals (Sweden)

    Anning Hu

    2018-01-01

    Full Text Available Background: Ancestor worship in China used to be an indispensable component of marriage and family life because it fostered an orientation toward perpetuating the family line. However, whether or not ancestor worship still matters in contemporary China is an open question. Objective: This article presents a comprehensive study of the association between ancestor worship practices and 1 the timing of transition to first marriage, 2 the pattern of childbearing, and 3 the orientation toward son preference. Methods: Drawing on the adult sample from the Chinese Family Panel Studies 2010, several multivariate models (Cox proportional hazard model, probit regression model, negative binomial regression models, and ordered probit model were fitted, corresponding to different types of outcome. Results: All else being equal, involvement in ancestor worship practices is correlated with 1 an early transition to marriage, 2 a larger number of children, 3 a higher probability of having at least one son, and 4 a larger number of sons. Conclusions: The relevance of the kinship tradition to family formation persists in contemporary China and has not faded away. Contribution: By highlighting the demographic implications of ancestor worship, this study illustrates the ongoing connection between culture and demography.

  16. Spherical particles formation under biaxial cyclic loading due to mesotunneling effect

    Directory of Open Access Journals (Sweden)

    A. Shanyavskiy

    2015-07-01

    Full Text Available Fatigue fracture surfaces of Al-based alloys with fatigue striations pattern and such wear debris pattern as spherical particles were investigated fractographically, on the bases of the OG’e spectroscopic analysis. The sequence of events during fatigue crack edges opening was discovered when the elliptical or spherical shapes of wear debris build up on the fracture surface in crosspieces between mesotunnels under mode III of mode I fatigue crack opening because of volume rotation. The cause of black colour of places with fretting patterns on the fracture surfaces of Al-based alloys is discussed.

  17. Mercury Toxicity on Sodium Pump and Organoseleniums Intervention: A Paradox

    Directory of Open Access Journals (Sweden)

    Ige Joseph Kade

    2012-01-01

    Full Text Available Mercury is an environmental poison, and the damage to living system is generally severe. The severity of mercury poisoning is consequent from the fact that it targets the thiol-containing enzymes, irreversibly oxidizing their critical thiol groups, consequently leading to an inactivation of the enzyme. The Na+/K+-ATPase is a sulfhydryl protein that is sensitive to Hg2+ assault. On the other hand, organoseleniums are a class of pharmacologically promising compounds with potent antioxidant effects. While Hg2+ oxidizes sulfhydryl groups of Na+/K+-ATPase under in vitro and in vivo conditions, the organoselenium compounds inhibit Na+/K+-ATPase in vitro but enhance its activities under in vivo conditions with concomitant increase in the level of endogenous thiols. Paradoxically, it appears that these two thiol oxidants can be used to counteract one another under in vivo conditions, and this hypothesis serves as the basis for this paper.

  18. New measurements on water ice photodesorption and product formation under ultraviolet irradiation

    Science.gov (United States)

    Cruz-Diaz, Gustavo A.; Martín-Doménech, Rafael; Moreno, Elena; Muñoz Caro, Guillermo M.; Chen, Yu-Jung

    2018-03-01

    The photodesorption of icy grain mantles has been claimed to be responsible for the abundance of gas-phase molecules towards cold regions. Being water a ubiquitous molecule, it is crucial to understand its role in photochemistry and its behaviour under an ultraviolet field. We report new measurements on the ultraviolet (UV) photodesorption of water ice and its H2, OH, and O2 photoproducts using a calibrated quadrupole mass spectrometer. Solid water was deposited under ultra-high-vacuum conditions and then UV-irradiated at various temperatures starting from 8 K with a microwave discharged hydrogen lamp. Deuterated water was used for confirmation of the results. We found a photodesorption yield of 1.3 × 10-3 molecules per incident photon for water and 0.7 × 10-3 molecules per incident photon for deuterated water at the lowest irradiation temperature, 8 K. The photodesorption yield per absorbed photon is given and comparison with astrophysical scenarios, where water ice photodesorption could account for the presence of gas-phase water towards cold regions in the absence of a thermal desorption process, is addressed.

  19. A model of disordered zone formation in Cu3Au under cascade-producing irradiation

    International Nuclear Information System (INIS)

    Kapinos, V.G.; Bacon, D.J.

    1995-01-01

    A model to describe the disordering of ordered Cu 3 Au under irradiation is proposed. For the thermal spike phase of a displacement cascade, the processes of heat evolution and conduction in the cascade region are modelled by solving the thermal conduction equation by a discretization method for a medium that can melt and solidify under appropriate conditions. The model considers disordering to result from cascade core melting, with the final disordered zone corresponding to the largest molten zone achieved. The initial conditions for this treatment are obtained by simulation of cascades by the MARLOWE code. The contrast of disordered zones imaged in a superlattice dark-field reflection and projected on the plane parallel to the surface of a thin foil was calculated. The average size of images from hundreds of cascades created by incident Cu + ions were calculated for different ion energies and compared with experimental transmission electron microscopy data. The model is in reasonable quantitative agreement with the experimentally observed trends. (author)

  20. Squeezout phenomena and boundary layer formation of a model ionic liquid under confinement and charging

    Science.gov (United States)

    Capozza, R.; Vanossi, A.; Benassi, A.; Tosatti, E.

    2015-02-01

    Electrical charging of parallel plates confining a model ionic liquid down to nanoscale distances yields a variety of charge-induced changes in the structural features of the confined film. That includes even-odd switching of the structural layering and charging-induced solidification and melting, with important changes of local ordering between and within layers, and of squeezout behavior. By means of molecular dynamics simulations, we explore this variety of phenomena in the simplest charged Lennard-Jones coarse-grained model including or excluding the effect a neutral tail giving an anisotropic shape to one of the model ions. Using these models and open conditions permitting the flow of ions in and out of the interplate gap, we simulate the liquid squeezout to obtain the distance dependent structure and forces between the plates during their adiabatic approach under load. Simulations at fixed applied force illustrate an effective electrical pumping of the ionic liquid, from a thick nearly solid film that withstands the interplate pressure for high plate charge to complete squeezout following melting near zero charge. Effective enthalpy curves obtained by integration of interplate forces versus distance show the local minima that correspond to layering and predict the switching between one minimum and another under squeezing and charging.

  1. The Arabidopsis Transcription Factor MYB112 Promotes Anthocyanin Formation during Salinity and under High Light Stress.

    Science.gov (United States)

    Lotkowska, Magda E; Tohge, Takayuki; Fernie, Alisdair R; Xue, Gang-Ping; Balazadeh, Salma; Mueller-Roeber, Bernd

    2015-11-01

    MYB transcription factors (TFs) are important regulators of flavonoid biosynthesis in plants. Here, we report MYB112 as a formerly unknown regulator of anthocyanin accumulation in Arabidopsis (Arabidopsis thaliana). Expression profiling after chemically induced overexpression of MYB112 identified 28 up- and 28 down-regulated genes 5 h after inducer treatment, including MYB7 and MYB32, which are both induced. In addition, upon extended induction, MYB112 also positively affects the expression of PRODUCTION OF ANTHOCYANIN PIGMENT1, a key TF of anthocyanin biosynthesis, but acts negatively toward MYB12 and MYB111, which both control flavonol biosynthesis. MYB112 binds to an 8-bp DNA fragment containing the core sequence (A/T/G)(A/C)CC(A/T)(A/G/T)(A/C)(T/C). By electrophoretic mobility shift assay and chromatin immunoprecipitation coupled to quantitative polymerase chain reaction, we show that MYB112 binds in vitro and in vivo to MYB7 and MYB32 promoters, revealing them as direct downstream target genes. We further show that MYB112 expression is up-regulated by salinity and high light stress, environmental parameters that both require the MYB112 TF for anthocyanin accumulation under these stresses. In contrast to several other MYB TFs affecting anthocyanin biosynthesis, MYB112 expression is not controlled by nitrogen limitation or an excess of carbon. Thus, MYB112 constitutes a regulator that promotes anthocyanin accumulation under abiotic stress conditions. © 2015 American Society of Plant Biologists. All Rights Reserved.

  2. Modeling of metal nanocluster growth on patterned substrates and surface pattern formation under ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Numazawa, Satoshi

    2012-11-01

    This work addresses the metal nanocluster growth process on prepatterned substrates, the development of atomistic simulation method with respect to an acceleration of the atomistic transition states, and the continuum model of the ion-beam inducing semiconductor surface pattern formation mechanism. Experimentally, highly ordered Ag nanocluster structures have been grown on pre-patterned amorphous SiO{sub 2} surfaces by oblique angle physical vapor deposition at room temperature. Despite the small undulation of the rippled surface, the stripe-like Ag nanoclusters are very pronounced, reproducible and well-separated. The first topic is the investigation of this growth process with a continuum theoretical approach to the surface gas condensation as well as an atomistic cluster growth model. The atomistic simulation model is a lattice-based kinetic Monte-Carlo (KMC) method using a combination of a simplified inter-atomic potential and experimental transition barriers taken from the literature. An effective transition event classification method is introduced which allows a boost factor of several thousand compared to a traditional KMC approach, thus allowing experimental time scales to be modeled. The simulation predicts a low sticking probability for the arriving atoms, millisecond order lifetimes for single Ag monomers and {approx}1 nm square surface migration ranges of Ag monomers. The simulations give excellent reproduction of the experimentally observed nanocluster growth patterns. The second topic specifies the acceleration scheme utilized in the metallic cluster growth model. Concerning the atomistic movements, a classical harmonic transition state theory is considered and applied in discrete lattice cells with hierarchical transition levels. The model results in an effective reduction of KMC simulation steps by utilizing a classification scheme of transition levels for thermally activated atomistic diffusion processes. Thermally activated atomistic movements

  3. Jet formation in spallation of metal film from substrate under action of femtosecond laser pulse

    Energy Technology Data Exchange (ETDEWEB)

    Inogamov, N. A., E-mail: nailinogamov@googlemail.com [Russian Academy of Sciences, Landau Institute for Theoretical Physics (Russian Federation); Zhakhovskii, V. V. [Dukhov All-Russia Research Institute of Automatics (Russian Federation); Khokhlov, V. A. [Russian Academy of Sciences, Landau Institute for Theoretical Physics (Russian Federation)

    2015-01-15

    It is well known that during ablation by an ultrashort laser pulse, the main contribution to ablation of the substance is determined not by evaporation, but by the thermomechanical spallation of the substance. For identical metals and pulse parameters, the type of spallation is determined by film thickness d{sub f}. An important gauge is metal heating depth d{sub T} at the two-temperature stage, at which electron temperature is higher than ion temperature. We compare cases with d{sub f} < d{sub T} (thin film) and d{sub f} ≫ d{sub T} (bulk target). Radius R{sub L} of the spot of heating by an optical laser is the next (after d{sub f}) important geometrical parameter. The morphology of film bulging in cases where d{sub f} < d{sub T} on the substrate (blistering) changes upon a change in radius R{sub L} in the range from diffraction limit R{sub L} ∼ λ to high values of R{sub L} ≫ λ, where λ ∼ 1 μm is the wavelength of optical laser radiation. When d{sub f} < d{sub T}, R{sub L} ∼ λ, and F{sub abs} > F{sub m}, gold film deposited on the glass target acquires a cupola-shaped blister with a miniature frozen nanojet in the form of a tip on the circular top of the cupola (F{sub abs} and F{sub m} are the absorbed energy and the melting threshold of the film per unit surface area of the film). A new physical mechanism leading to the formation of the nanojet is proposed.

  4. Response of Xylella fastidiosa to zinc: decreased culturability, increased exopolysaccharide production, and formation of resilient biofilms under flow conditions.

    Science.gov (United States)

    Navarrete, Fernando; De La Fuente, Leonardo

    2014-02-01

    The bacterial plant pathogen Xylella fastidiosa produces biofilm that accumulates in the host xylem vessels, affecting disease development in various crops and bacterial acquisition by insect vectors. Biofilms are sensitive to the chemical composition of the environment, and mineral elements being transported in the xylem are of special interest for this pathosystem. Here, X. fastidiosa liquid cultures were supplemented with zinc and compared with nonamended cultures to determine the effects of Zn on growth, biofilm, and exopolysaccharide (EPS) production under batch and flow culture conditions. The results show that Zn reduces growth and biofilm production under both conditions. However, in microfluidic chambers under liquid flow and with constant bacterial supplementation (closer to conditions inside the host), a dramatic increase in biofilm aggregates was seen in the Zn-amended medium. Biofilms formed under these conditions were strongly attached to surfaces and were not removed by medium flow. This phenomenon was correlated with increased EPS production in stationary-phase cells grown under high Zn concentrations. Zn did not cause greater adhesion to surfaces by individual cells. Additionally, viability analyses suggest that X. fastidiosa may be able to enter the viable but nonculturable state in vitro, and Zn can hasten the onset of this state. Together, these findings suggest that Zn can act as a stress factor with pleiotropic effects on X. fastidiosa and indicate that, although Zn could be used as a bactericide treatment, it could trigger the undesired effect of stronger biofilm formation upon reinoculation events.

  5. Simulation of Patterned Glass Film Formation in the Evaporating Colloidal Liquid under IR Heating

    Science.gov (United States)

    Kolegov, K. S.

    2017-12-01

    The paper theoretically studies the method of evaporative lithography in combination with external infrared heating. This method makes it possible to form solid microstructures of the required relief shape as a result of evaporation of the liquid film of the colloidal solution under the mask. The heated particles are sintered easier, so there are no cracks in the obtained structure, unlike the structure obtained employing the standard method of evaporative lithography. The paper puts forward a modification of the mathematical model which allows to describe not only heat and mass transfer at the initial stage of the process, but also the phase transition of colloidal solution into glass. Aqueous latex is taken as an example. The resulting final form of solid film is in good agreement with the experimental data of other authors.

  6. On the number of neurons and time scale of integration underlying the formation of percepts in the brain.

    Science.gov (United States)

    Wohrer, Adrien; Machens, Christian K

    2015-03-01

    All of our perceptual experiences arise from the activity of neural populations. Here we study the formation of such percepts under the assumption that they emerge from a linear readout, i.e., a weighted sum of the neurons' firing rates. We show that this assumption constrains the trial-to-trial covariance structure of neural activities and animal behavior. The predicted covariance structure depends on the readout parameters, and in particular on the temporal integration window w and typical number of neurons K used in the formation of the percept. Using these predictions, we show how to infer the readout parameters from joint measurements of a subject's behavior and neural activities. We consider three such scenarios: (1) recordings from the complete neural population, (2) recordings of neuronal sub-ensembles whose size exceeds K, and (3) recordings of neuronal sub-ensembles that are smaller than K. Using theoretical arguments and artificially generated data, we show that the first two scenarios allow us to recover the typical spatial and temporal scales of the readout. In the third scenario, we show that the readout parameters can only be recovered by making additional assumptions about the structure of the full population activity. Our work provides the first thorough interpretation of (feed-forward) percept formation from a population of sensory neurons. We discuss applications to experimental recordings in classic sensory decision-making tasks, which will hopefully provide new insights into the nature of perceptual integration.

  7. Formation of Frenkel pairs and diffusion of self-interstitial in Si under normal and hydrostatic pressure: Quantumchemical simulation

    International Nuclear Information System (INIS)

    Gusakov, Vasilii; Belko, Victor; Dorozhkin, Nikolai

    2009-01-01

    A theoretical modeling of the formation of Frenkel pairs and the diffusion of a self-interstitial atom in silicon crystals at normal and high (hydrostatic) pressures has been performed using quantum-chemical (NDDO-PM5), methods. It is shown that, in a silicon crystal, the most stable configuration of a self-interstitial atom in the neutral charge state (I 0 ) is the split configuration . The tetrahedral configuration is not stable, an interstitial atom being shifted from T position in a new position T 1 on a distance Δd=0.2 A. The hexagonal configuration is not stable in NDDO approximation. The split interstitial configuration remains the more stable configuration under hydrostatic pressure (P a ( →T 1 )=0.59 eV, E a (T 1 →neighboring T 1 )=0.1 eV and E a (T 1 → )=0.23 eV. The hydrostatic pressure (P<80 kbar) increases the activation barrier for diffusion of self-interstitial atoms in silicon crystals. The energies of the formation of a separate Frenkel pair, a self-interstitial atom, and a vacancy are determined. It is demonstrated that the hydrostatic pressure decreases the energy of the formation of Frenkel pairs.

  8. Experimental Behavior of Sulfur Under Primitive Planetary Differentiation Processes, the Sulfide Formations in Enstatite Meteorites and Implications for Mercury.

    Science.gov (United States)

    Malavergne, V.; Brunet, F.; Righter, K.; Zanda, B.; Avril, C.; Borensztajn, S.; Berthet, S.

    2012-01-01

    Enstatite meteorites are the most reduced naturally-occuring materials of the solar system. The cubic monosulfide series with the general formula (Mg,Mn,Ca,Fe)S are common phases in these meteorite groups. The importance of such minerals, their formation, composition and textural relationships for understanding the genesis of enstatite chondrites (EC) and aubrites, has long been recognized (e.g. [1]). However, the mechanisms of formation of these sulfides is still not well constrained certainly because of possible multiple ways to produce them. We propose to simulate different models of formation in order to check their mineralogical, chemical and textural relevancies. The solubility of sulfur in silicate melts is of primary interest for planetary mantles, particularly for the Earth and Mercury. Indeed, these two planets could have formed, at least partly, from EC materials (e.g. [2, 3, 4]). The sulfur content in silicate melts depends on the melt composition but also on pressure (P), temperature (T) and oxygen fugacity fO2. Unfortunately, there is no model of general validity in a wide range of P-T-fO2-composition which describes precisely the evolution of sulfur content in silicate melts, even if the main trends are now known. The second goal of this study is to constrain the sulfur content in silicate melts under reducing conditions and different temperatures.

  9. Mechanisms for the Formations of the Thymine Under Astrophysical Conditions and Implications for the Origin of Life

    Science.gov (United States)

    Bera, Partha P.; Nuevo, Michel; Materese, Christopher K.; Sandford, Scott A.; Lee, Timothy J.

    2016-01-01

    Nucleobases are the carriers of the genetic information in ribonucleic acid and deoxyribonucleic acid (DNA) for all life on Earth. Their presence in meteorites clearly indicates that compounds of biological importance can form via non-biological processes in extraterrestrial environments. Recent experimental studies have shown that the pyrimidine-based nucleobases uracil and cytosine can be easily formed from the ultraviolet irradiation of pyrimidine in H2O-rich ice mixtures that simulate astrophysical processes. In contrast, thymine, which is found only in DNA, is more difficult to form under the same experimental conditions, as its formation usually requires a higher photon dose. Earlier quantum chemical studies confirmed that the reaction pathways were favorable provided that several H2O molecules surrounded the reactants. However, the present quantum chemical study shows that the formation of thymine is limited because of the inefficiency of the methylation of pyrimidine and its oxidized derivatives in an H2O ice, as supported by the laboratory studies. Our results constrain the formation of thymine in astrophysical environments and thus the inventory of organic molecules delivered to the early Earth and have implications for the role of thymine and DNA in the origin of life.

  10. Induced leaf intercellular CO₂, photosynthesis, potassium and nitrate retention and strawberry early fruit formation under macronutrient limitation.

    Science.gov (United States)

    Li, Hong; Li, Tingxian; Fu, Gang; Katulanda, Panchali

    2013-07-01

    Relationships between induced high leaf intercellular CO₂ concentrations, leaf K⁺ and NO₃⁻ ion movement and early fruit formation under macronutrient limitation are not well understood. We examined the effects and interactions of reduced K/N input treatments on leaf intercellular CO₂, photosynthesis rate, carboxylation and water use efficiency, berry formation as well as leaf/fruit K⁺, NO₃⁻ and photosynthate retention of strawberry (Fragaria × ananassa Duch.) to enhance low-input agriculture. The field study was conducted in Nova Scotia, eastern Canada during 2009-2010. The experimental treatments consisted of five K₂O rates (0, 6, 12, 18, and 24 kg ha(-1)) and five N rates (0, 5, 10, 15, and 20 kg ha(-1)), representing respectively, 0, 25, 50, 75, and 100 % of regular macronutrient recommendations based on the soil testing. The treatments were arranged in a split-plot design with three blocks in the field. The cultivar was 'Mira', a June-bearing crop. The results showed that strawberry plants treated with 25 %-reduced inputs could induce significantly higher leaf intercellular CO₂ concentrations to improve plant photosynthesis, carboxylation and water use efficiency and translocation of leaf/fruit K⁺ and dissolved solids, which could advance berry formation by 6 days and produce significantly higher marketable yields (P < 0.05). Higher leaf intercellular CO₂ inhibited leaf/fruit NO₃⁻ ion retention, but this inhibition did not occur in leaf/fruit K⁺ retention. Linear interactions of the K/N treatments were significant on fruit marketable yields, intercellular CO₂, net photosynthesis, leaf transpiration rates, and leaf temperatures (P < 0.05). It was concluded that higher leaf CO₂ could enhance plant photosynthesis, promote plant carboxylation and water use efficiency, and advance berry formation, but it could inhibit leaf NO₃⁻ retention. This inhibition did not find in leaf K⁺ ion and dissolved solid retention. Overlay co

  11. Socioeconomic data base report for the Paradox Basin, Utah

    International Nuclear Information System (INIS)

    1984-11-01

    This report is published as a product of the Civilian Radioactive Waste Management (CRWM) Program. The objective of this program is to develop terminal waste storage facilities in deep, stable geologic formations for high-level nuclear wastes, including spent fuel elements from commercial power reactors and transuranic nuclear waste for which the Federal Government is responsible. The Socioeconomic Analysis Report for the Paradox Basin in Utah is part of the CRWM Program described above. This report presents baseline data on the demography, economics, community facilities, government and fiscal structure, and social structure characteristics in San Juan and Grand Counties, the socioeconomic study area. The technical criteria upon which a repository site(s) will be selected, evaluated, and licensed for high-level waste disposal will be partially based on the data in this report

  12. Influence of Implant Neck Design on Bone Formation Under Mechanical Repetitive Loading: Histomorphometric and Microcomputed Tomographic Studies in Rabbit Tibiae.

    Science.gov (United States)

    Yasutake, Munenori; Kuroshima, Shinichiro; Ishimoto, Takuya; Nakano, Takayoshi; Sawase, Takashi

    2016-04-01

    The aim of this study was to investigate effects of implant neck design on the original concept of osseointegration and bone formation when applying mechanical repetitive loading by bone-integrated implants. Twenty-eight anodized Ti-6Al-4V alloy implants with +60° or -60° grooves in the implant neck were placed in the proximal tibial metaphysis of 14 rabbits. Fourteen implants received mechanical repetitive loading along the long axis of the implant for 8 weeks at 12 weeks after implant placement. The remaining 14 implants received no loading. Histomorphometric and microcomputed tomographic analyses were then performed. No effect of neck design was observed without mechanical loading, whereas osseointegration around the +60° grooves was upregulated with mechanical loading. Calculated load effects on bone structure around the implant neck with +60° grooves were larger when compared with the -60° grooves under mechanical loading. These findings indicate that the establishment of osseointegration and bone formation around the implant neck with +60° grooves is superior to those with -60° grooves under loaded conditions.

  13. Helium accumulation and bubble formation in FeCoNiCr alloy under high fluence He+ implantation

    Science.gov (United States)

    Chen, Da; Tong, Y.; Li, H.; Wang, J.; Zhao, Y. L.; Hu, Alice; Kai, J. J.

    2018-04-01

    Face-centered cubic (FCC) high-entropy alloys (HEA), as emerging alloys with equal-molar or near equal-molar constituents, show a promising radiation damage resistance under heavy ion bombardment, making them potential for structural material application in next-generation nuclear reactors, but the accumulation of light helium ions, a product of nuclear fission reaction, has not been studied. The present work experimentally studied the helium accumulation and bubble formation at implantation temperatures of 523 K, 573 K and 673 K in a homogenized FCC FeCoNiCr HEA, a HEA showing excellent radiation damage resistance under heavy ion irradiation. The size and population density of helium bubbles in FeCoNiCr samples were quantitatively analyzed through transmission electron microscopy (TEM), and the helium content existing in bubbles were estimated from a high-pressure Equation of State (EOS). We found that the helium diffusion in such condition was dominated by the self-interstitial/He replacement mechanism, and the corresponding activation energy in FeCoNiCr is comparable with the vacancy migration energy in Ni and austenitic stainless steel but only 14.3%, 31.4% and 51.4% of the accumulated helium precipitated into helium bubbles at 523 K, 573 K and 673 K, respectively, smaller than the pure Ni case. Importantly, the small bubble size suggested that FeCoNiCr HEA has a high resistance of helium bubble formation compared with Ni and steels.

  14. Lipid peroxidation is another potential mechanism besides pore-formation underlying hemolysis of tentacle extract from the jellyfish Cyanea capillata.

    Science.gov (United States)

    Wang, Tao; Wen, Xiao-Juan; Mei, Xiao-Bin; Wang, Qian-Qian; He, Qian; Zheng, Jie-Min; Zhao, Jie; Xiao, Liang; Zhang, Li-Ming

    2013-01-09

    This study was performed to explore other potential mechanisms underlying hemolysis in addition to pore-formation of tentacle extract (TE) from the jellyfish Cyanea capillata. A dose-dependent increase of hemolysis was observed in rat erythrocyte suspensions and the hemolytic activity of TE was enhanced in the presence of Ca2+, which was attenuated by Ca2+ channel blockers (Diltiazem, Verapamil and Nifedipine). Direct intracellular Ca2+ increase was observed after TE treatment by confocal laser scanning microscopy, and the Ca2+ increase could be depressed by Diltiazem. The osmotic protectant polyethylenglycol (PEG) significantly blocked hemolysis with a molecular mass exceeding 4000 Da. These results support a pore-forming mechanism of TE in the erythrocyte membrane, which is consistent with previous studies by us and other groups. The concentration of malondialdehyde (MDA), an important marker of lipid peroxidation, increased dose-dependently in rat erythrocytes after TE treatment, while in vitro hemolysis of TE was inhibited by the antioxidants ascorbic acid-Vitamin C (Vc)-and reduced glutathione (GSH). Furthermore, in vivo hemolysis and electrolyte change after TE administration could be partly recovered by Vc. These results indicate that lipid peroxidation is another potential mechanism besides pore-formation underlying the hemolysis of TE, and both Ca2+ channel blockers and antioxidants could be useful candidates against the hemolytic activity of jellyfish venoms.

  15. Lipid Peroxidation Is another Potential Mechanism besides Pore-Formation Underlying Hemolysis of Tentacle Extract from the Jellyfish Cyanea capillata

    Directory of Open Access Journals (Sweden)

    Tao Wang

    2013-01-01

    Full Text Available This study was performed to explore other potential mechanisms underlying hemolysis in addition to pore-formation of tentacle extract (TE from the jellyfish Cyanea capillata. A dose-dependent increase of hemolysis was observed in rat erythrocyte suspensions and the hemolytic activity of TE was enhanced in the presence of Ca2+, which was attenuated by Ca2+ channel blockers (Diltiazem, Verapamil and Nifedipine. Direct intracellular Ca2+ increase was observed after TE treatment by confocal laser scanning microscopy, and the Ca2+ increase could be depressed by Diltiazem. The osmotic protectant polyethylenglycol (PEG significantly blocked hemolysis with a molecular mass exceeding 4000 Da. These results support a pore-forming mechanism of TE in the erythrocyte membrane, which is consistent with previous studies by us and other groups. The concentration of malondialdehyde (MDA, an important marker of lipid peroxidation, increased dose-dependently in rat erythrocytes after TE treatment, while in vitro hemolysis of TE was inhibited by the antioxidants ascorbic acid—Vitamin C (Vc—and reduced glutathione (GSH. Furthermore, in vivo hemolysis and electrolyte change after TE administration could be partly recovered by Vc. These results indicate that lipid peroxidation is another potential mechanism besides pore-formation underlying the hemolysis of TE, and both Ca2+ channel blockers and antioxidants could be useful candidates against the hemolytic activity of jellyfish venoms.

  16. Cellular inhibitory behavior underlying the formation of retinal direction selectivity in the starburst network.

    Science.gov (United States)

    Poznanski, R R

    2010-09-01

    Optical imaging of dendritic calcium signals provided evidence of starburst amacrine cells exhibiting calcium bias to somatofugal motion. In contrast, it has been impractical to use a dual-patch clamp technique to record membrane potentials from both proximal dendrites and distal varicosities of starburst amacrine cells in order to unequivocally prove that they are directionally sensitive to voltage, as was first suggested almost two decades ago. This paper aims to extend the passive cable model to an active cable model of a starburst amacrine cell that is intrinsically dependent on the electrical properties of starburst amacrine cells, whose various macroscopic currents are described quantitatively. The coupling between voltage and calcium just below the membrane results in a voltage-calcium system of coupled nonlinear Volterra integral equations whose solutions must be integrated into a prescribed model for example, for a synaptic couplet of starburst amacrine cells. Networks of starburst amacrine cells play a fundamental role in the retinal circuitry underlying directional selectivity. It is suggested that the dendritic plexus of starburst amacrine cells provides the substrate for the property of directional selectivity, while directional selectivity is a property of the exclusive layerings and confinement of their interconnections within the sublaminae of the inner plexiform layer involving cone bipolar cells and directionally selective ganglion cells.

  17. Mechanisms underlying reductant-induced reactive oxygen species formation by anticancer copper(II) compounds.

    Science.gov (United States)

    Kowol, Christian R; Heffeter, Petra; Miklos, Walter; Gille, Lars; Trondl, Robert; Cappellacci, Loredana; Berger, Walter; Keppler, Bernhard K

    2012-03-01

    Intracellular generation of reactive oxygen species (ROS) via thiol-mediated reduction of copper(II) to copper(I) has been assumed as the major mechanism underlying the anticancer activity of copper(II) complexes. The aim of this study was to compare the anticancer potential of copper(II) complexes of Triapine (3-aminopyridine-2-carboxaldehyde thiosemicarbazone; currently in phase II clinical trials) and its terminally dimethylated derivative with that of 2-formylpyridine thiosemicarbazone and that of 2,2'-bipyridyl-6-carbothioamide. Experiments on generation of oxidative stress and the influence of biologically relevant reductants (glutathione, ascorbic acid) on the anticancer activity of the copper complexes revealed that reductant-dependent redox cycling occurred mainly outside the cells, leading to generation and dismutation of superoxide radicals resulting in cytotoxic amounts of H(2)O(2). However, without extracellular reductants only weak intracellular ROS generation was observed at IC(50) levels, suggesting that cellular thiols are not involved in copper-complex-induced oxidative stress. Taken together, thiol-induced intracellular ROS generation might contribute to the anticancer activity of copper thiosemicarbazone complexes but is not the determining factor.

  18. NdFeO3 nanocrystals under glycine nitrate combustion formation

    Science.gov (United States)

    Tugova, Ekaterina; Yastrebov, Sergey; Karpov, Oleg; Smith, Roger

    2017-06-01

    Nanocrystalline perovskite NdFeO3 with the orthorhombic structure was prepared by a glycine nitrate combustion method under different technological conditions. The starting materials Fe(NO3)3 · 9H2O,Nd(NO3)3 · 6H2O in stoichiometric amounts and H2NCH2COOH were used. These quantities were varied by changing the ratio of glycine moles to metal nitrate moles (G/N) in the range between 0.25 and 0.75. The prepared NdFeO3 nanocrystals were characterised by X-ray diffraction (XRD) and electron microscopy. Decomposition of the XRD diffraction profile using Voigt contours was exploited for analysis of the pattern in the area where the most prominent diffraction peak was situated. We demonstrate that Voigt functions reduce to Lorentzians for G / N = 0.75 and 0.55 . A volume-weighted diameter distribution function was derived using the width of the Lorentzians. The log-normal shape of the distribution is discussed in terms of the model, assuming exponential growth of cluster size in the time available for the NdFeO3 nanograin to grow.

  19. Nanopore formation on Au coated pyramid under electron beam irradiations (plasmonic nanopore on pyramid

    Directory of Open Access Journals (Sweden)

    Seong Soo Choi

    2016-03-01

    Full Text Available There have been tremendous interests about the single molecule analysis using a sold-state nanopore. The solid-state nanopore can be fabricated either by drilling technique, or diffusion technique by using electron beam irradiations. The solid-state SiN nanopore device with electrical detection technique recently fabricated, however, the solid-state Au nanopore with optical detection technique can be better utilized as the next generation single molecule sensor. In this report, the nanometer size openings with its size less than 10 nm on the diffused membrane on the 200 nm Au pyramid were fabricated by using field emission scanning electron microscopy (FESEM electron beam irradiations, transmission electron microscopy (TEM, etc. After the sample was being kept under a room environment for several months, several Au (111 clusters with ~6 nm diameter formed via Ostwald ripening are observed using a high resolution TEM imaging. The nanopore with Au nanoclusters on the diffused membrane can be utilized as an optical nanopore device. Keywords: Electron beam irradiation, Surface diffusion, Carbon contamination, Au cluster, Ostwald ripening

  20. Investigation of fracture conductivity under in situ conditions as a function of frac- and formation parameters

    Energy Technology Data Exchange (ETDEWEB)

    Meyn, V.; Lajcsak, I.

    1998-10-01

    Because of their low permeability, deep-lying gas fields are often developed by the fracturing technique. Essential for the economy of this measure is a high fracture conductivity which persists over a long period. The objective of the project was the investigation of the various factors influencing the fracture conductivity under reservoir conditions. Besides the breaking strength of proppants, which is decisive for the conductivity attainable at high confining pressure, the long-term stability, the embedment and the transport of fragments, which results in plugging, were examined. With the proppants Superprop and Carboprop HC, fracture conductivity exhibits only a slight dependence on the closure pressure. Transport of fragments and embedment play no important role. With resin-coated proppants, conductivity is not improved appreciably. The resin-coating doesn`t resist reservoir conditions. After only one week, aquathermolytic products were detected. (orig.) [Deutsch] Tiefliegende Erdgasfelder werden aufgrund ihrer niedrigen Permeabilitaet haeufig durch eine Frac-Behandlung erschlossen. Eine wesentliche Voraussetzung fuer die Wirtschaftlichkeit einer solchen Massnahme ist eine hohe Rissleitfaehigkeit, die ueber einen langen Zeitraum bestehen bleibt. Ziel des Projektes war die Untersuchung der verschiedenen Faktoren, die die Rissleitfaehigkeit unter Lagerstaettenbedingungen beeinflussen. Neben der Bruchfestigkeit des Stuetzmittels, die fuer die bei hohen Schliessdrucken erreichbaren Rissleitfaehigkeiten entscheidend ist, wurde die Langzeitstabilitaet, das Embedment und der zu Verstopfung fuehrende Transport von Bruchstuecken untersucht. Die Stuetzmittel Superprop und Carboprop HC weisen nur eine geringe Abhaengigkeit der Rissleitfaehigkeit vom Schliessdruck auf. Der Bruchstuecktransport sowie das Embedment spielen nur eine untergeordnete Rolle. Durch die Verwendung von beschichtetem Stuetzmittel wird die Rissleitfaehigkeit nicht wesentlich erhoeht. Die Beschichtung

  1. Galilean Hydrostatic Paradox and Archimedes Law

    Directory of Open Access Journals (Sweden)

    Fernando Lang da Silveira

    2009-08-01

    Full Text Available Traditional pedagogy has underestimated the presence of some mysteries and paradoxes in Physics teaching. Naïve inductivistic approaches  in Science education have also contributed to the fact that some important theoretical assumptions are usually discarded. Historical, conceptual  and experimental analysis of Physics development can positively contribute to restore the importance of such assumptions in physics teaching. In this article we analyze the so  called  Galilean Hydrostatic Paradox, a  mystery  directly connected  to  Archimedes Law of  Hydrostatics. Experimental analysis   of   this   theme is presented in a well-documented  photographic way and conclusions are drawn as an example to show the extent to which a competent analysis of such hidden assumptions can subvert traditional and orthodox education in Physics.

  2. Paradoxical and less paradoxical effects of thought suppression: a critical review.

    Science.gov (United States)

    Rassin, E; Merckelbach, H; Muris, P

    2000-11-01

    The process of consciously trying to avoid certain thoughts is referred to as thought suppression. Experimental research has documented that thought suppression may have paradoxical effects in that it leads to an increased frequency of the to-be-suppressed thought intruding consciousness. It has also been claimed that suppression has disruptive effects on episodic memory (i.e., a less paradoxical effect). The present article critically evaluates studies on the paradoxical and less paradoxical effects of thought suppression. More specifically, the issue of whether thought suppression plays a causative role in the development of various psychopathological symptoms is addressed. While laboratory studies have come up with highly consistent findings about the paradoxical effects of thought suppression, there is, as yet, little reason to believe that such effects are implicated in the etiology of obsessions, phobias, or other psychopathological conditions. Relatively little work has been done on the alleged memory effects of thought suppression. The studies that have examined this issue have found mixed results. Accordingly, the case for the amnestic power of thought suppression is weak. Alternative explanations and competing theories are discussed, and it is concluded that research concerned with the psychopathological consequences of thought suppression would benefit from development of better taxonomies of intrusive thinking and cognitive avoidance strategies.

  3. International Criminal Law & Its Paradoxes

    DEFF Research Database (Denmark)

    Carlson, Kerstin Bree

    2017-01-01

    This article challenges international criminal tribunals' (ICTs) capacity to perform the socially constitutive work of transitional justice. Highlighting paradigmatic ICT jurisprudence, it shows both the "progress" and "justice" constructs central to the work and legitimacy of international...... criminal law are unrealizable under current ICT practice. This is due to international criminal law's foundational, legitimizing basis in natural law, rather than political liberalism. The article calls for a revision of ICT institutional accountability structures....

  4. 'Climategate': Paradoxical Metaphors and Political Paralysis

    OpenAIRE

    Brigitte Nerlich

    2010-01-01

    Climate scepticism in the sense of climate denialism or contrarianism is not a new phenomenon, but it has recently been very much in the media spotlight. When, in November 2009, emails by climate scientists were published on the internet without their authors’ consent, a debate began in which climate sceptic bloggers used an extended network of metaphors to contest (climate) science. This article follows the so-called ‘climategate’ debate on the web and shows how a paradoxical mixture of reli...

  5. Two Paradoxes in Linear Regression Analysis

    OpenAIRE

    FENG, Ge; PENG, Jing; TU, Dongke; ZHENG, Julia Z.; FENG, Changyong

    2016-01-01

    Summary Regression is one of the favorite tools in applied statistics. However, misuse and misinterpretation of results from regression analysis are common in biomedical research. In this paper we use statistical theory and simulation studies to clarify some paradoxes around this popular statistical method. In particular, we show that a widely used model selection procedure employed in many publications in top medical journals is wrong. Formal procedures based on solid statistical theory shou...

  6. The paradox of declining female happiness

    OpenAIRE

    Stevenson, Betsey; Wolfers, Justin

    2009-01-01

    By many objective measures the lives of women in the United States have improved over the past 35 years, yet we show that measures of subjective well-being indicate that women's happiness has declined both absolutely and relative to men. The paradox of women's declining relative well-being is found across various datasets, measures of subjective well-being, and is pervasive across demographic groups and industrialized countries. Relative declines in female happiness have eroded a gender gap i...

  7. Progress in understanding the molecular oxygen paradox - function of mitochondrial reactive oxygen species in cell signaling.

    Science.gov (United States)

    Kuksal, Nidhi; Chalker, Julia; Mailloux, Ryan J

    2017-10-26

    The molecular oxygen (O2) paradox was coined to describe its essential nature and toxicity. The latter characteristic of O2 is associated with the formation of reactive oxygen species (ROS), which can damage structures vital for cellular function. Mammals are equipped with antioxidant systems to fend off the potentially damaging effects of ROS. However, under certain circumstances antioxidant systems can become overwhelmed leading to oxidative stress and damage. Over the past few decades, it has become evident that ROS, specifically H2O2, are integral signaling molecules complicating the previous logos that oxyradicals were unfortunate by-products of oxygen metabolism that indiscriminately damage cell structures. To avoid its potential toxicity whilst taking advantage of its signaling properties, it is vital for mitochondria to control ROS production and degradation. H2O2 elimination pathways are well characterized in mitochondria. However, less is known about how H2O2 production is controlled. The present review examines the importance of mitochondrial H2O2 in controlling various cellular programs and emerging evidence for how production is regulated. Recently published studies showing how mitochondrial H2O2 can be used as a secondary messenger will be discussed in detail. This will be followed with a description of how mitochondria use S-glutathionylation to control H2O2 production.

  8. Suppressing of γ-crystal formation in metallocene-based isotactic polypropylene during isothermal crystallization under shear flow.

    Science.gov (United States)

    Wang, Yan; Chen, Chen; Xu, Jia-Zhuang; Lei, Jun; Mao, Yimin; Li, Zhong-Ming; Hsiao, Benjamin S

    2012-04-26

    The effect of shear flow on isothermal crystallization behavior of γ-crystals in metallocene-based isotactic polypropylene melt was investigated by in situ synchrotron wide-angle X-ray diffraction (WAXD). In the sample under weak shear (at strain of 300% for 30 s duration), simultaneous evolution of α- and γ-crystals occurred, and the final fraction of γ-crystals (fγ) was 0.66, which was identical to the undeformed sample (PP-Static). In this scenario, α-crystals probably served as effective seeds for nucleation of γ-crystals. In the samples under strong shear (at strain of 500% for 30 s duration or long-time continuous shear at strains of 100% and 500%), the sequential emergence of α- and γ-crystals was observed. In this case, molten polymer chains were probably constrained by the surrounding crystals after intense short-time shear and/or maintained their extended chain conformation after long-time shear. These oriented chains had little chance to form the γ-crystals directly, behaving very differently from the relaxed chains. Under strong shear fields, the emergence of γ-crystals was delayed or inhibited, whereas the fγ value was also decreased rapidly. A simple model for the possible pathway of γ-crystal formation in the strong shear environment was proposed.

  9. Monitoring Microstructural Evolution and Crack Formation in a Solid Propellant under Incremental Strain Condition- Using Digital Radiography X-Ray Techniques

    National Research Council Canada - National Science Library

    Liu, C

    2004-01-01

    In this study, the change of microstructure and the formation of cracks in a solid propellant under an incremental strain loading condition were investigated using digital radiography x-ray techniques...

  10. Fermi's paradox: The last challenge for copernicanism?

    Directory of Open Access Journals (Sweden)

    Ćirković M.M.

    2009-01-01

    Full Text Available We review Fermi's paradox (or the 'Great Silence' problem, not only arguably the oldest and crucial problem for the Search for ExtraTerrestrial Intelligence (SETI, but also a conundrum of profound scientific, philosophical and cultural importance. By a simple analysis of observation selection effects, the correct resolution of Fermi's paradox is certain to tell us something about the future of humanity. Already more than three quarters of century old puzzle and a quarter of century since the last major review paper in the field by G. David Brin has generated many ingenious discussions and hypotheses. We analyze the often tacit methodological assumptions built in various answers to this puzzle and attempt a new classification of the numerous solutions proposed in an already huge literature on the subject. Finally, we consider the ramifications of various classes of hypotheses for the practical SETI projects. Somewhat paradoxically, it seems that the class of (neocatastrophic hypotheses gives, on the balance, the strongest justification to optimism regarding our current and near-future SETI efforts.

  11. Obesity and poverty paradox in developed countries

    Directory of Open Access Journals (Sweden)

    Wioletta Żukiewicz-Sobczak

    2014-09-01

    Full Text Available Obesity is a civilization disease and the proportion of people suffering from it continues to grow, especially in the developed countries. Number of obese people in Europe has increased threefold over the last 20 years. The paradox of obesity and poverty relationship is observed especially in the developed and developing countries. In developing countries, along with economic development and income growth, the number of people with overweight and obesity is increasing. This paradox has a relationship with both the easy availability and low cost of highly processed foods containing ‘empty calories’ and no nutritional value. To date, this paradox has been described in the United States and the United Kingdom, although many European countries are also experiencing high percentages of obese people. Among the reasons for the growing obesity in the population of poor people are: higher unemployment, lower education level, and irregular meals. Another cause of obesity is low physical activity, which among the poor is associated with a lack of money for sports equipment. Due to the large rate of deaths caused by diseases directly linked to obesity, the governments of many countries implement prevention programmes of overweight and obesity. These programmes are based primarily on educating the public about a healthy lifestyle based on healthy eating, daily physical activity and avoiding alcohol and cigarettes.

  12. Laying the ghost of twin paradox

    Directory of Open Access Journals (Sweden)

    Popović Marko

    2009-01-01

    Full Text Available Someone's true age is not written in his ID, but in his biomarkers. Aging process is not caused by time passing, but by thermodynamically laws. Entropy, extent of metabolic reaction, and temperature are Lorentz invariant, so these facts make twin paradox impossible because there is no way for one twin to age slower than the other even if the time in his frame is dilated. Entropy is the function of state, not time. So as much as standard thermodynamics concerns, the path between two points in space is equivalent to the path between two states. Whether the point B is reached by moving faster using the longer way (with time dilatation, or slower by using shortcut (without time dilatation, the state of the system after completing the road should be the same. This is supported by the fact that when two twins reach the same space-time point (point B in which the state parameters are the same. If we use entropy as an age parameter, then both twins have the same entropy value and are exactly the same biological age. Therefore, the twin paradox is a logical mistake based on wrong first premise. Bergson symmetry is not necessary any more to explain the impossibility of twin paradox.

  13. Identifying Quantum Structures in the Ellsberg Paradox

    Science.gov (United States)

    Aerts, Diederik; Sozzo, Sandro; Tapia, Jocelyn

    2014-10-01

    Empirical evidence has confirmed that quantum effects occur frequently also outside the microscopic domain, while quantum structures satisfactorily model various situations in several areas of science, including biological, cognitive and social processes. In this paper, we elaborate a quantum mechanical model which faithfully describes the Ellsberg paradox in economics, showing that the mathematical formalism of quantum mechanics is capable to represent the ambiguity present in this kind of situations, because of the presence of contextuality. Then, we analyze the data collected in a concrete experiment we performed on the Ellsberg paradox and work out a complete representation of them in complex Hilbert space. We prove that the presence of quantum structure is genuine, that is, interference and superposition in a complex Hilbert space are really necessary to describe the conceptual situation presented by Ellsberg. Moreover, our approach sheds light on `ambiguity laden' decision processes in economics and decision theory, and allows to deal with different Ellsberg-type generalizations, e.g., the Machina paradox.

  14. Length-scale and strain rate-dependent mechanism of defect formation and fracture in carbon nanotubes under tensile loading

    Science.gov (United States)

    Javvaji, Brahmanandam; Raha, S.; Mahapatra, D. Roy

    2017-02-01

    Electromagnetic and thermo-mechanical forces play a major role in nanotube-based materials and devices. Under high-energy electron transport or high current densities, carbon nanotubes fail via sequential fracture. The failure sequence is governed by certain length scale and flow of current. We report a unified phenomenological model derived from molecular dynamic simulation data, which successfully captures the important physics of the complex failure process. Length-scale and strain rate-dependent defect nucleation, growth, and fracture in single-walled carbon nanotubes with diameters in the range of 0.47 to 2.03 nm and length which is about 6.17 to 26.45 nm are simulated. Nanotubes with long length and small diameter show brittle fracture, while those with short length and large diameter show transition from ductile to brittle fracture. In short nanotubes with small diameters, we observe several structural transitions like Stone-Wales defect initiation, its propagation to larger void nucleation, formation of multiple chains of atoms, conversion to monatomic chain of atoms, and finally complete fracture of the carbon nanotube. Hybridization state of carbon-carbon bonds near the end cap evolves, leading to the formation of monatomic chain in short nanotubes with small diameter. Transition from ductile to brittle fracture is also observed when strain rate exceeds a critical value. A generalized analytical model of failure is established, which correlates the defect energy during the formation of atomic chain with aspect ratio of the nanotube and strain rate. Variation in the mechanical properties such as elastic modulus, tensile strength, and fracture strain with the size and strain rate shows important implications in mitigating force fields and ways to enhance the life of electronic devices and nanomaterial conversion via fracture in manufacturing.

  15. Length-scale and strain rate-dependent mechanism of defect formation and fracture in carbon nanotubes under tensile loading

    Energy Technology Data Exchange (ETDEWEB)

    Javvaji, Brahmanandam [Indian Institute of Science, Department of Aerospace Engineering (India); Raha, S. [Indian Institute of Science, Department of Computational and Data Sciences (India); Mahapatra, D. Roy, E-mail: droymahapatra@aero.iisc.ernet.in [Indian Institute of Science, Department of Aerospace Engineering (India)

    2017-02-15

    Electromagnetic and thermo-mechanical forces play a major role in nanotube-based materials and devices. Under high-energy electron transport or high current densities, carbon nanotubes fail via sequential fracture. The failure sequence is governed by certain length scale and flow of current. We report a unified phenomenological model derived from molecular dynamic simulation data, which successfully captures the important physics of the complex failure process. Length-scale and strain rate-dependent defect nucleation, growth, and fracture in single-walled carbon nanotubes with diameters in the range of 0.47 to 2.03 nm and length which is about 6.17 to 26.45 nm are simulated. Nanotubes with long length and small diameter show brittle fracture, while those with short length and large diameter show transition from ductile to brittle fracture. In short nanotubes with small diameters, we observe several structural transitions like Stone-Wales defect initiation, its propagation to larger void nucleation, formation of multiple chains of atoms, conversion to monatomic chain of atoms, and finally complete fracture of the carbon nanotube. Hybridization state of carbon-carbon bonds near the end cap evolves, leading to the formation of monatomic chain in short nanotubes with small diameter. Transition from ductile to brittle fracture is also observed when strain rate exceeds a critical value. A generalized analytical model of failure is established, which correlates the defect energy during the formation of atomic chain with aspect ratio of the nanotube and strain rate. Variation in the mechanical properties such as elastic modulus, tensile strength, and fracture strain with the size and strain rate shows important implications in mitigating force fields and ways to enhance the life of electronic devices and nanomaterial conversion via fracture in manufacturing.

  16. Fusion of blastomeres in mouse embryos under the action of femtosecond laser radiation. Efficiency of blastocyst formation and embryo development

    Energy Technology Data Exchange (ETDEWEB)

    Osychenko, A A; Zalesskii, A D; Krivokharchenko, A S; Zhakhbazyan, A K; Nadtochenko, V A [N N Semenov Institute of Chemical Physics, Russian Academy of Sciences, Moscow (Russian Federation); Ryabova, A V [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    2015-05-31

    Using the method of femtosecond laser surgery we study the fusion of two-cell mouse embryos under the action of tightly focused femtosecond laser radiation with the fusion efficiency reaching 60%. The detailed statistical analysis of the efficiency of blastomere fusion and development of the embryo up to the blastocyst stage after exposure of the embryos from different mice to a femtosecond pulse is presented. It is shown that the efficiency of blastocyst formation essentially depends on the biological characteristics of the embryo, namely, the strain and age of the donor mouse. The possibility of obtaining hexaploid embryonal cells using the methods of femtosecond laser surgery is demonstrated. (extreme light fields and their applications)

  17. Social goal-objective formation, democracy and national interest a theory of political economy under fuzzy rationality

    CERN Document Server

    Dompere, Kofi Kissi

    2014-01-01

    This book presents the development of a theory of social goal-objective formation and its relationship to national interest and social vision under a democratic decision-choice system with imperfect information structure. It provides a framework for the application of fuzzy logic and its mathematics to the analysis in resolving conflicts in individual preferences in the collective decision-choice space without violence. The book demonstrates how to use fuzzy logic and its mathematics in the study of economics, social sciences and other complex systems. It also presents the use of collaborative tools of opposites, duality, polarity, continuum in fuzzy paradigm with its logic, laws of thought and mathematics in developing a new approach to the theory of political economy in order to enhance the constructs of social decision-choice theory.

  18. Observations of CO{sub 2} clathrate hydrate formation and dissolution under deep-ocean disposal conditions

    Energy Technology Data Exchange (ETDEWEB)

    Warzinski, R.P.; Cugini, A.V. [Department of Energy, Pittsburgh, PA (United States); Holder, G.D. [Univ. of Pittsburgh, Pittsburgh, PA (United States)

    1995-11-01

    Disposal of anthropogenic emissions of CO{sub 2} may be required to mitigate rises in atmospheric levels of this greenhouse gas if other measures are ineffective and the worst global warming scenarios begin to occur. Long-term storage of large quantities of CO{sub 2} has been proposed, but the feasibility of large land and ocean disposal options remains to be established. Determining the fate of liquid CO{sub 2} injected into the ocean at depths greater than 500 m is complicated by uncertainties associated with the physical behavior of CO{sub 2} under these conditions, in particular the possible formation of the ice-like CO{sub 2} clathrate hydrate. Resolving this issue is key to establishing the technical feasibility of this option. Experimental and theoretical work in this area is reported.

  19. Modeling the photochemical transformation of nitrobenzene under conditions relevant to sunlit surface waters: Reaction pathways and formation of intermediates.

    Science.gov (United States)

    Vione, Davide; De Laurentiis, Elisa; Berto, Silvia; Minero, Claudio; Hatipoglu, Arzu; Cinar, Zekiye

    2016-02-01

    Nitrobenzene (NB) would undergo photodegradation in sunlit surface waters, mainly by direct photolysis and triplet-sensitized oxidation, with a secondary role of the *OH reaction. Its photochemical half-life time would range from a few days to a couple of months under fair-weather summertime irradiation, depending on water chemistry and depth. NB phototransformation gives phenol and the three nitrophenol isomers, in different yields depending on the considered pathway. The minor *OH role in degradation would make NB unsuitable as *OH probe in irradiated natural water samples, but the selectivity towards *OH could be increased by monitoring the formation of phenol from NB+*OH. The relevant reaction would proceed through ipso-addition of *OH on the carbon atom bearing the nitro-group, forming a pre-reactive complex that would evolve into a transition state (and then into a radical addition intermediate) with very low activation energy barrier. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Managing Innovation Paradox in the Sustainable Innovation Ecosystem: A Case Study of Ambidextrous Capability in a Focal Firm

    Directory of Open Access Journals (Sweden)

    Delin Zeng

    2017-11-01

    Full Text Available To achieve sustainable development, focal firms should balance two paradoxical kinds of innovation activities: exploitative and exploratory ones. Published works found that ambidexterity is an effective way to resolve paradoxical tensions, but few in-depth studies have been conducted to explore the innovation paradox of focal firms in the innovation ecosystem from an ambidextrous capability perspective. This paper takes China Spacesat Co., Ltd. as the case to study focal firms’ management of innovation paradoxes in the sustainable innovation ecosystem and finds that: (1 Sustainable innovation is an ecosystem in which focal firms’ internal functional departments, including the product department, technical center, and Makers’ groups, cooperate with external organizations, including component suppliers, scientific research institutes, and government departments, closely and complementarily; (2 In the exploitative and exploratory innovations of complex products, focal firms in the sustainable innovation ecosystem mainly confront three paradoxes: profit drive vs. breakthroughs in the strategic intent of sustainable innovation of the profit-driven model, tight vs. loose coupling of sustainable innovation, and sustainable innovation driven by discipline vs. that by passion; (3 Focal firms in the innovation ecosystem resolve these three innovation paradoxes with structural, contextual, and coordinated ambidextrous capabilities, and build innovation paradox management mechanisms with three steps in sequence, namely by establishing dual sustainable strategic innovation units, strengthening sustainable organizational ties between the internal and external, while co-creating and sharing innovation values, and, finally, promoting the formation and development of their sustainable innovation ecosystem. This paper complements and enriches the innovation ecosystem and ambidextrous capability theory, providing significant practical guidance to the

  1. Intravenous curcumin efficacy on healing and scar formation in rabbit ear wounds under nonischemic, ischemic, and ischemia-reperfusion conditions.

    Science.gov (United States)

    Jia, Shengxian; Xie, Ping; Hong, Seok Jong; Galiano, Robert; Singer, Adam; Clark, Richard A F; Mustoe, Thomas A

    2014-01-01

    Curcumin, a spice found in turmeric, is widely used in alternative medicine for its purported anti-inflammatory and antioxidant activities. The goal of this study was to test the curcumin efficacy on rabbit ear wounds under nonischemic, ischemic, and ischemia-reperfusion conditions. Previously described models were utilized in 58 New Zealand White rabbits. Immediately before wounding, rabbits were given intravenous crude or pure curcumin (6 μg/kg, 30 μg/kg, or 60 μg/kg) dissolved in 1% ethanol. Specimens were collected at 7-8 days to evaluate the effects on wound healing and at 28 days to evaluate the effects on hypertrophic scarring. Student's t test was applied to screen difference between any treatment and control group, whereas analysis of variance was applied to further analyze for all treatment groups in aggregate in some specific experiments. Treatment with crude curcumin suggested accelerated wound healing that reached significance for reepithelialization in lower and medium doses and granulation tissue formation in lower dose. Purified curcumin became available and was used for all later experiments. Treatment with pure curcumin suggested accelerated wound healing that reached significance for reepithelialization in lower and medium doses and granulation tissue formation in lower dose. Treatment with pure curcumin significantly promoted nonischemic wound healing in a dose-response fashion compared with controls as judged by increased reepithelialization and granulation tissue formation. Improved wound healing was associated with significant decreases in pro-inflammatory cytokines interleukin (IL)-1 and IL-6 as well as the chemokine IL-8. Curcumin also significantly reduced hypertrophic scarring. The effects of curcumin were examined under conditions of impaired healing including ischemic and ischemia-reperfusion wound healing, and beneficial effects were also seen, although the dose response was less clear. Systemically administrated pure

  2. The Oxygen Paradox, the French Paradox, and age-related diseases.

    Science.gov (United States)

    Davies, Joanna M S; Cillard, Josiane; Friguet, Bertrand; Cadenas, Enrique; Cadet, Jean; Cayce, Rachael; Fishmann, Andrew; Liao, David; Bulteau, Anne-Laure; Derbré, Frédéric; Rébillard, Amélie; Burstein, Steven; Hirsch, Etienne; Kloner, Robert A; Jakowec, Michael; Petzinger, Giselle; Sauce, Delphine; Sennlaub, Florian; Limon, Isabelle; Ursini, Fulvio; Maiorino, Matilde; Economides, Christina; Pike, Christian J; Cohen, Pinchas; Salvayre, Anne Negre; Halliday, Matthew R; Lundquist, Adam J; Jakowec, Nicolaus A; Mechta-Grigoriou, Fatima; Mericskay, Mathias; Mariani, Jean; Li, Zhenlin; Huang, David; Grant, Ellsworth; Forman, Henry J; Finch, Caleb E; Sun, Patrick Y; Pomatto, Laura C D; Agbulut, Onnik; Warburton, David; Neri, Christian; Rouis, Mustapha; Cillard, Pierre; Capeau, Jacqueline; Rosenbaum, Jean; Davies, Kelvin J A

    2017-12-01

    A paradox is a seemingly absurd or impossible concept, proposition, or theory that is often difficult to understand or explain, sometimes apparently self-contradictory, and yet ultimately correct or true. How is it possible, for example, that oxygen "a toxic environmental poison" could be also indispensable for life (Beckman and Ames Physiol Rev 78(2):547-81, 1998; Stadtman and Berlett Chem Res Toxicol 10(5):485-94, 1997)?: the so-called Oxygen Paradox (Davies and Ursini 1995; Davies Biochem Soc Symp 61:1-31, 1995). How can French people apparently disregard the rule that high dietary intakes of cholesterol and saturated fats (e.g., cheese and paté) will result in an early death from cardiovascular diseases (Renaud and de Lorgeril Lancet 339(8808):1523-6, 1992; Catalgol et al. Front Pharmacol 3:141, 2012; Eisenberg et al. Nat Med 22(12):1428-1438, 2016)?: the so-called, French Paradox. Doubtless, the truth is not a duality and epistemological bias probably generates apparently self-contradictory conclusions. Perhaps nowhere in biology are there so many apparently contradictory views, and even experimental results, affecting human physiology and pathology as in the fields of free radicals and oxidative stress, antioxidants, foods and drinks, and dietary recommendations; this is particularly true when issues such as disease-susceptibility or avoidance, "healthspan," "lifespan," and ageing are involved. Consider, for example, the apparently paradoxical observation that treatment with low doses of a substance that is toxic at high concentrations may actually induce transient adaptations that protect against a subsequent exposure to the same (or similar) toxin. This particular paradox is now mechanistically explained as "Adaptive Homeostasis" (Davies Mol Asp Med 49:1-7, 2016; Pomatto et al. 2017a; Lomeli et al. Clin Sci (Lond) 131(21):2573-2599, 2017; Pomatto and Davies 2017); the non-damaging process by which an apparent toxicant can activate biological signal

  3. Price Paradox and Strategic Choice of "Vegetable Basket" in China

    OpenAIRE

    Li, Wu

    2011-01-01

    By using the analysis method of game theory, this paper analyzes the phenomenon of price paradox of vegetable basket in China and its reason as follows: me price paradox of vegetable basket in China is that if the vegetable is cheap, it will harm farmers, and if the vegetable is expensive, it will harm people; high-cost logistics, low negotiation status of vegetable growers and cooperation predicament are responsible for price paradox. Based on the theoretical basis of strategic choice-theory...

  4. The Surprise Examination Paradox and the Second Incompleteness Theorem

    OpenAIRE

    Kritchman, Shira; Raz, Ran

    2010-01-01

    We give a new proof for Godel's second incompleteness theorem, based on Kolmogorov complexity, Chaitin's incompleteness theorem, and an argument that resembles the surprise examination paradox. We then go the other way around and suggest that the second incompleteness theorem gives a possible resolution of the surprise examination paradox. Roughly speaking, we argue that the flaw in the derivation of the paradox is that it contains a hidden assumption that one can prove the consistency of the...

  5. Increased Oil Production and Reserves Utilizing Secondary/Tertiary Recovery Techniques on Small Reservoirs in the Paradox Basin, Utah

    International Nuclear Information System (INIS)

    Chidsey Jr., Thomas C.

    2003-01-01

    The primary objective of this project was to enhance domestic petroleum production by field demonstration and technology transfer of an advanced-oil-recovery technology in the Paradox Basin, southeastern Utah. If this project can demonstrate technical and economic feasibility, the technique can be applied to approximately 100 additional small fields in the Paradox Basin alone, and result in increased recovery of 150 to 200 million barrels (23,850,000-31,800,000 m3) of oil. This project was designed to characterize five shallow-shelf carbonate reservoirs in the Pennsylvanian (Desmoinesian) Paradox Formation and choose the best candidate for a pilot demonstration project for either a waterflood or carbon-dioxide-(CO2-) miscible flood project. The field demonstration, monitoring of field performance, and associated validation activities will take place within the Navajo Nation, San Juan County, Utah

  6. [Formation of geochemistry in underground river under rainfall conditions: an examule for underground river at Xueyu Cave, Chongqing].

    Science.gov (United States)

    Wang, Feng-Kang; Liang, Zuo-Bing; Yu, Zheng-Liang; Jiang, Ze-Li

    2014-10-01

    Through the monitoring of geochemical indexes in underground river of Xueyu Cave in Chongqing under rainfall conditions, we found that all indexes responded quickly to rainfall, and there was a correlation among them. Each index was analyzed with the principal component analysis, three main components were extracted which can represent 82.761% of the information to reflect the formation of geochemistry in underground river under rainfall conditions. The results showed that the contribution rates of soil leaching represented as increased concentration of total Fe, total Mn, and Al3+, and dilution effect represented as reduced concentration of K+, Na+ and Sr2+ to the change of geochemical characteristics were 41.718%, which should be paid more attentions for its great damage to karst soil and safety of drinking water. Karst water dissolution of dolomite and recharge area of agricultural activities, caverns were 29.958%, as for karst water on limestone dissolution represented, as increased concentration of Ca2+ the contribution rate was 11.084%.

  7. A paradox of cumulative culture.

    Science.gov (United States)

    Kobayashi, Yutaka; Wakano, Joe Yuichiro; Ohtsuki, Hisashi

    2015-08-21

    Culture can grow cumulatively if socially learnt behaviors are improved by individual learning before being passed on to the next generation. Previous authors showed that this kind of learning strategy is unlikely to be evolutionarily stable in the presence of a trade-off between learning and reproduction. This is because culture is a public good that is freely exploited by any member of the population in their model (cultural social dilemma). In this paper, we investigate the effect of vertical transmission (transmission from parents to offspring), which decreases the publicness of culture, on the evolution of cumulative culture in both infinite and finite population models. In the infinite population model, we confirm that culture accumulates largely as long as transmission is purely vertical. It turns out, however, that introduction of even slight oblique transmission drastically reduces the equilibrium level of culture. Even more surprisingly, if the population size is finite, culture hardly accumulates even under purely vertical transmission. This occurs because stochastic extinction due to random genetic drift prevents a learning strategy from accumulating enough culture. Overall, our theoretical results suggest that introducing vertical transmission alone does not really help solve the cultural social dilemma problem. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Paradox reconsidered: Methane oversaturation in well-oxygenated lake waters

    DEFF Research Database (Denmark)

    Tang, Kam W.; McGinnis, Daniel F.; Frindte, Katharina

    2014-01-01

    The widely reported paradox of methane oversaturation in oxygenated water challenges the prevailing paradigm that microbial methanogenesis only occurs under anoxic conditions. Using a combination of field sampling, incubation experiments, and modeling, we show that the recurring mid-water methane...... peak in Lake Stechlin, northeast Germany, was not dependent on methane input from the littoral zone or bottom sediment or on the presence of known micro-anoxic zones. The methane peak repeatedly overlapped with oxygen oversaturation in the seasonal thermocline. Incubation experiments and isotope...... analysis indicated active methane production, which was likely linked to photosynthesis and/or nitrogen fixation within the oxygenated water, whereas lessening of methane oxidation by light allowed accumulation of methane in the oxygen-rich upper layer. Estimated methane efflux from the surface water...

  9. Standard format and content guide for financial assurance mechanisms required for decommissioning under 10 CFR parts 30, 40, 70, and 72

    International Nuclear Information System (INIS)

    1989-08-01

    The Standard Format and Content Guide for Financial Assurance Mechanisms Required for Decommissioning under 10 CFR Parts 30, 40, 70, and 72, discusses the information to be provided in a license application and established a uniform format for presenting the information required to meet the decommissioning licensing requirements. The use of the Standard Format and Content Guide will (1) help ensure that the license application contains the information required by the regulations, (2) aid the applicant in ensuring that the information is complete, (3) help persons reading the Standard Format and Content Guide to locate information, and (4) contribute to shortening the time required for the review process. The Standard Format and Content Guide ensures that the information required to perform the review is provided, and in a useable format

  10. Interim guidance on the standard format and content of financial assurance mechanisms required for decommissioning under 10 CFR Parts 30, 40, and 70

    International Nuclear Information System (INIS)

    1988-12-01

    Interim Guidance on the Standard Format and Content of Financial Assurance Mechanisms Required for Decommissioning under 10 CFR Parts 30, 40, and 70, NUREG-1336, discusses the information to be provided in a license application and established a uniform format for presenting the information required to meet the decommissioning licensing requirements. The use of the Standard Format will (1) help ensure that the license application contains the information required by the regulations, (2) aid the applicant in ensuring that the information is complete, (3) help persons reading the Standard Format to locate information, and (4) contribute to shortening the time required for the review process. The Standard Format and Content (NUREG-1336) ensures that the information required to perform the review is provided, and in a useable format

  11. Community treatment orders: exploring the paradox of personalisation under compulsion

    NARCIS (Netherlands)

    Banks, Laura Catherine; Stroud, Julia; Doughty, Karolina

    2016-01-01

    The introduction of supervised community treatment, delivered through community treatment orders (CTOs) in England and Wales, contrasts with the policy of personalisation, which aims to provide service users autonomy and choice over services. This article draws upon findings from a primarily

  12. A Paradox of Women's Health Rights under Decentralized Indonesia

    International Development Research Centre (IDRC) Digital Library (Canada)

    x31

    . ➢Every sub-district now has a Community Health. Center (Puskesmas). In the rural areas, however, the distance from a village to the sub- district is quite far, especially when road condition is bad and transportation is scarce. ➢Not all villages ...

  13. The yield condition strongly influences the formation of Dugdale plastic strips ahead of crack tips under tensile plane stress loading conditions

    Science.gov (United States)

    Unger, David J.

    2012-11-01

    A finite element analysis indicates a good correlation between the Dugdale plastic strip model and a linear elastic/perfectly plastic material under plane stress loading conditions for a flow theory of plasticity based on the Tresca yield condition. A similar analysis under the von Mises yield condition reveals no plastic strip formation.

  14. Molecular and Ultrastructural Mechanisms Underlying Yellow Dwarf Symptom Formation in Wheat after Infection of Barley Yellow Dwarf Virus.

    Science.gov (United States)

    Rong, Wei; Wang, Xindong; Wang, Xifeng; Massart, Sebastien; Zhang, Zengyan

    2018-04-13

    Wheat ( Tritium aestivum L.) production is essential for global food security. Infection of barley yellow dwarf virus-GAV (BYDV-GAV) results in wheat showing leaf yellowing and plant dwarfism symptom. To explore the molecular and ultrastructural mechanisms underlying yellow dwarf symptom formation in BYDV-GAV-infected wheat, we investigated the chloroplast ultrastructure via transmission electron microscopy (TEM), examined the contents of the virus, H₂O₂, and chlorophyll in Zhong8601, and studied the comparative transcriptome through microarray analyses in the susceptible wheat line Zhong8601 after virus infection. TEM images indicated that chloroplasts in BYDV-GAV-infected Zhong8601 leaf cells were fragmentized. Where thylakoids were not well developed, starch granules and plastoglobules were rare. Compared with mock-inoculated Zhong8601, chlorophyll content was markedly reduced, but the virus and H₂O₂ contents were significantly higher in BYDV-GAV-infected Zhong8601. The transcriptomic analyses revealed that chlorophyll biosynthesis and chloroplast related transcripts, encoding chlorophyll a/b binding protein, glucose-6-phosphate/phosphate translocator 2, and glutamyl-tRNA reductase 1, were down-regulated in BYDV-GAV-infected Zhong8601. Some phytohormone signaling-related transcripts, including abscisic acid (ABA) signaling factors (phospholipase D alpha 1 and calcineurin B-like protein 9) and nine ethylene response factors, were up-regulated. Additionally, reactive oxygen species (ROS)-related genes were transcriptionally regulated in BYDV-GAV infected Zhong8601, including three up-regulated transcripts encoding germin-like proteins (promoting ROS accumulation) and four down-regulated transcripts encoding peroxides (scavenging ROS). These results clearly suggest that the yellow dwarf symptom formation is mainly attributed to reduced chlorophyll content and fragmentized chloroplasts caused by down-regulation of the chlorophyll and chloroplast biosynthesis

  15. Physiology, Fe(II oxidation, and Fe mineral formation by a marine planktonic cyanobacterium grown under ferruginous conditions

    Directory of Open Access Journals (Sweden)

    Elizabeth D. Swanner

    2015-10-01

    Full Text Available Evidence for Fe(II oxidation and deposition of Fe(III-bearing minerals from anoxic or redox-stratified Precambrian oceans has received support from decades of sedimentological and geochemical investigation of Banded Iron Formations (BIF. While the exact mechanisms of Fe(II oxidation remains equivocal, reaction with O2 in the marine water column, produced by cyanobacteria or early oxygenic phototrophs, was likely. In order to understand the role of cyanobacteria in the deposition of Fe(III minerals to BIF, we must first know how planktonic marine cyanobacteria respond to ferruginous (anoxic and Fe(II-rich waters in terms of growth, Fe uptake and homeostasis, and Fe mineral formation. We therefore grew the common marine cyanobacterium Synechococcus PCC 7002 in closed bottles that began anoxic, and contained Fe(II concentrations that span the range of possible concentrations in Precambrian seawater. These results, along with cell suspension experiments, indicate that Fe(II is likely oxidized by this strain via chemical oxidation with oxygen produced during photosynthesis, and not via any direct enzymatic or photosynthetic pathway. Imaging of the cell-mineral aggregates with scanning electron microscopy (SEM and confocal laser scanning microscopy (CLSM are consistent with extracellular precipitation of Fe(III (oxyhydroxide minerals, but that >10% of Fe(III sorbs to cell surfaces rather than precipitating. Proteomic experiments support the role of reactive oxygen species (ROS in Fe(II toxicity to Synechococcus PCC 7002. The proteome expressed under low Fe conditions included multiple siderophore biosynthesis and siderophore and Fe transporter proteins, but most siderophores are not expressed during growth with Fe(II. These results provide a mechanistic and quantitative framework for evaluating the geochemical consequences of perhaps life’s greatest metabolic innovation, i.e. the evolution and activity of oxygenic photosynthesis, in ferruginous

  16. A novel bioreactor for mechanobiological studies of engineered heart valve tissue formation under pulmonary arterial physiological flow conditions.

    Science.gov (United States)

    Ramaswamy, Sharan; Boronyak, Steven M; Le, Trung; Holmes, Andrew; Sotiropoulos, Fotis; Sacks, Michael S

    2014-12-01

    The ability to replicate physiological hemodynamic conditions during in vitro tissue development has been recognized as an important aspect in the development and in vitro assessment of engineered heart valve tissues. Moreover, we have demonstrated that studies aiming to understand mechanical conditioning require separation of the major heart valve deformation loading modes: flow, stretch, and flexure (FSF) (Sacks et al., 2009, "Bioengineering Challenges for Heart Valve Tissue Engineering," Annu. Rev. Biomed. Eng., 11(1), pp. 289-313). To achieve these goals in a novel bioreactor design, we utilized a cylindrical conduit configuration for the conditioning chamber to allow for higher fluid velocities, translating to higher shear stresses on the in situ tissue specimens while retaining laminar flow conditions. Moving boundary computational fluid dynamic (CFD) simulations were performed to predict the flow field under combined cyclic flexure and steady flow (cyclic-flex-flow) states using various combinations of flow rate, and media viscosity. The device was successfully constructed and tested for incubator housing, gas exchange, and sterility. In addition, we performed a pilot experiment using biodegradable polymer scaffolds seeded with bone marrow derived stem cells (BMSCs) at a seeding density of 5 × 10(6) cells/cm(2). The constructs were subjected to combined cyclic flexure (1 Hz frequency) and steady flow (Re = 1376; flow rate of 1.06 l/min (LPM); shear stress in the range of 0-9 dynes/cm(2) for 2 weeks to permit physiological shear stress conditions. Assays revealed significantly (P Engineered Tissue Formation: Implications for Engineered Heart Valve Tissues," Biomaterials, 27(36), pp. 6083-6095). The implications of this novel design are that fully coupled or decoupled physiological flow, flexure, and stretch modes of engineered tissue conditioning investigations can be readily accomplished with the inclusion of this device in experimental protocols on

  17. Topology Control Algorithms for Spacecraft Formation Flying Networks Under Connectivity and Time-Delay Constraints, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — SSCI is proposing to develop a set of topology control algorithms for a formation flying spacecraft that can be used to design and evaluate candidate formation...

  18. Paradoks kłamcy (Liar Paradox

    Directory of Open Access Journals (Sweden)

    Jan Wawrzyniak

    2011-09-01

    Full Text Available The aim of the article is to determine what role the liar sentence plays in our language. On the one hand, it seems to be well formed formula, and on the other, it does not seem to have any clear sense. At the beginning of the article I point what form an adequate solution of the liar paradox should take. In my opinion it could not consist in giving rules which do not allow to build such a sentence. The paradox remains unsolved until there is such a language in which it could be expressed.In the first part of the text I try to explain why Tarski’s solution is not satisfactory. If the semantical definition of truth is correct, the liar sentence could not lead to a contradiction because formulas which are not well formed could not be premisesof any inference. From that follows that the so called liar paradox does not arise and that leads to the conclusion: ‘the reconstruction’ of the liar propounded by Tarski could not be correct.In the second part I present an approach to the liar which appeals to Frege’s and Wittgenstein’s conceptions of language. The conclusion of my consideration is that the liar sentence is nonsense, which means it is not given any sense – either its logical form is determined but we do not fix any definite meaning to some parts of it, or an attempt to determine its logical form in the standard way leads to regressad infinitum.

  19. MODELING PARADOXES IN NOVICE AND EXPERT DESIGN

    DEFF Research Database (Denmark)

    Dorst, Kees; Hansen, Claus Thorp

    2011-01-01

    In their ICED09 paper ‘Problem formulation as a discursive activity’, the authors have used an extensive educational case study to explore a framework for describing design as a discursive activity, centered around the paradoxical nature of the problem situation. The ‘working definition’ for para...... at play in a design situation, and extract themes that can lead to reformulation of the problem as well as the creation of innovative solutions. This behaviour is compared to the ways of working of novice designers (students) in the original case study....

  20. Managing the paradoxes of discussion pedagogy

    Directory of Open Access Journals (Sweden)

    Jody S. Piro

    2015-12-01

    Full Text Available Discussion pedagogy is part of a larger curricular goal that intersects the two aspirations of diversity of perspectives and democratic inquiry in that it challenges stereotypes and assumptions through student discourse. Yet, teaching with discussion is a complex and sometimes ambiguous endeavor that leaves instructors feeling pulled between desirable, but seemingly contradictory, goals. This article discusses these paradoxes of instructional choices and student outcomes that instructors may negotiate through polarity management, a theoretical framework that focuses on values that are diametrically opposed, yet interdependent upon each other. Implications of polarity management for discussion pedagogy are highlighted.

  1. O paradoxo de Chalmers Chalmers' paradox

    Directory of Open Access Journals (Sweden)

    Gustavo Leal-Toledo

    2009-01-01

    Full Text Available O Argumento dos Zumbis proposto por Chalmers, ao contrário de defender o dualismo, bane as qualia para um "mundo" onde elas não podem influenciar o julgamento que fazemos sobre nós mesmos. Por este motivo, pelo próprio argumento, podemos ser um zumbi e não saber. A isso Chalmers chamou de The Paradox of Phenomenal Judgment. O problema é que ele aceita tal paradoxo como parte de sua própria teoria. No entanto, este movimento filosófico não é aceitável e este paradoxo mina a teoria de Chalmers por dentro mostrando que o argumento dos zumbis é, na verdade, um argumento contra o dualismo. Chalmers tenta resolver este problema com uma série de argumentos que tem como base o fato de que a consciência é um bruto explanandum indubitável. No entanto, tal tentativa fracassa por uma série de razões que mostram que mesmo se ele estivesse correto, ainda poderíamos ser um zumbi e não saber.The Zombie Argument proposed by Chalmers, instead of working as a defense of dualism, banishes qualia to a 'world' where they cannot influence our judgments about ourselves. For this reason, according to the argument itself, we may be all zombies and not know it. This is what Chalmers called The Paradox of Phenomenal Judgment. The problem is that he accepts this paradox as part of his theory. This philosophical move, however, is not acceptable, for the paradox undermines Chalmers' theory, by showing that the zombie argument is, actually, an argument against dualism. Chalmers tries to solve this problem with many arguments based on the status of consciousness as brute indubitable explanandum. However, this attempt is a failure by a series of reasons showing that, even if he were right, we could still be zombies and not know it.

  2. Paradox of integration-A computational model

    Science.gov (United States)

    Krawczyk, Małgorzata J.; Kułakowski, Krzysztof

    2017-02-01

    The paradoxical aspect of integration of a social group has been highlighted by Blau (1964). During the integration process, the group members simultaneously compete for social status and play the role of the audience. Here we show that when the competition prevails over the desire of approval, a sharp transition breaks all friendly relations. However, as was described by Blau, people with high status are inclined to bother more with acceptance of others; this is achieved by praising others and revealing her/his own weak points. In our model, this action smooths the transition and improves interpersonal relations.

  3. Induced Seismicity of the Paradox Valley Brine Injection

    Science.gov (United States)

    Bachmann, C. E.; Foxall, W.; Daley, T. M.

    2013-12-01

    The Paradox Valley Unit (PVU) is operated by the U.S. Bureau of Reclamation (USBR) and is built to control the water quality of the Dolores River - a feeder of the Colorado River. Brine is extracted along the river from several shallow wells. Before it is injected into a 4.8km deep well for long-term storage, it is filtered at a surface-treatment facility. The target zone of the injection is a subhorizontal formation of a Mississippian-age limestone. The first injection test started in 1991, continuous injections started in 1996 and are still ongoing. The injection of the fluid in the underground induces micro-seismicity that is monitored by the USBR with the 15-station Paradox Valley Seismic Network. This network located more then 5700 events in the 20 years since the injection started. The locations of the seismic events give crucial insights to the pathways of the injected fluid. In this study we analyze the seismicity up to the end of 2011, which does not include the magnitude 3.9 event that caused a temporary shut down of the PVU in January 2013. The largest event included in our study period is an event with M4.3 of May 2000. The majority (75%) of events are micro-seismic events with magnitudes of 1 or smaller; only 74 events have magnitudes larger or equal to 2.5 of which only 4 are larger or equal to 3.5. Most of the seismicity is constrained to the vicinity of the injection well with roughly 80% of the events occurring within a 4km radius. However, there is one active zone more then 10 km away from the injection well that showed first activity in late 2010. More than 500 micro-seismic events occurred within several weeks in this new zone. The goal behind this study is to understand the processes behind a long-term injection of fluid into the underground where no circulation takes place. While other such projects exist, such as different wastewater injections, none of them has been monitored as well as the Paradox Valley seismicity and or has been going on

  4. Effects of Calcination on the Crystallography and Nonbiogenic Aragonite Formation of Ark Clam Shell under Ambient Condition

    Directory of Open Access Journals (Sweden)

    Chee Wah Loy

    2016-01-01

    Full Text Available This paper presents a study of crystallographic evolution of disposed ark clam shell (ACS after calcination at 400–1400°C which was kept at room temperature under ambient condition in Malaysia during nine months. A better understanding of hydration and recarbonation of ACS powder (≤63 μm after calcination was discovered by PXRD and FTIR. The research focuses on the crystallographic transformation, biogenic calcite decomposition, and unusual atmospheric aragonite formation in ACS after calcination and atmospheric air exposure. Ex situ PXRD showed calcite present in ACS at ≤900°C. ACS transformed to pyrogenic fcc CaO at ≥800°C after three months. Long term atmospheric air exposure of decarbonized ACS caused nucleation of nonbiogenic aragonite, vaterite, calcite, and portlandite. However, in situ PXRD analysis of ACS at instantaneous temperature without cooling process does not indicate the presence of aragonite, vaterite, and portlandite crystals. FTIR spectra revealed CaO–CO2 bond in ACS dissociated with temperature (600–900°C to form CaO and CO2. Ca–OH bond was also traced in FTIR spectra of ≥700°C. It resulted by hydroadsorption of CaO with H2O in atmospheric air.

  5. Diamond-like carbon coating under oleic acid lubrication: Evidence for graphene oxide formation in superlow friction

    Science.gov (United States)

    de Barros Bouchet, Maria Isabel; Martin, Jean Michel; Avila, José; Kano, Makoto; Yoshida, Kentaro; Tsuruda, Takeshi; Bai, Shandan; Higuchi, Yuji; Ozawa, Nobuki; Kubo, Momoji; Asensio, Maria C.

    2017-04-01

    The achievement of the superlubricity regime, with a friction coefficient below 0.01, is the Holy Grail of many tribological applications, with the potential to have a remarkable impact on economic and environmental issues. Based on a combined high-resolution photoemission and soft X-ray absorption study, we report that superlubricity can be realized for engineering applications in bearing steel coated with ultra-smooth tetrahedral amorphous carbon (ta-C) under oleic acid lubrication. The results show that tribochemical reactions promoted by the oil lubrication generate strong structural changes in the carbon hybridization of the ta-C hydrogen-free carbon, with initially high sp3 content. Interestingly, the macroscopic superlow friction regime of moving mechanical assemblies coated with ta-C can be attributed to a few partially oxidized graphene-like sheets, with a thickness of not more than 1 nm, formed at the surface inside the wear scar. The sp2 planar carbon and oxygen-derived species are the hallmark of these mesoscopic surface structures created on top of colliding asperities as a result of the tribochemical reactions induced by the oleic acid lubrication. Atomistic simulations elucidate the tribo-formation of such graphene-like structures, providing the link between the overall atomistic mechanism and the macroscopic experimental observations of green superlubricity in the investigated ta-C/oleic acid tribological systems.

  6. Formation of Combustible Hydrocarbons and H2 during Photocatalytic Decomposition of Various Organic Compounds under Aerated and Deaerated Conditions

    Directory of Open Access Journals (Sweden)

    Sylwia Mozia

    2014-11-01

    Full Text Available A possibility of photocatalytic production of useful aliphatic hydrocarbons and H2 from various organic compounds, including acetic acid, methanol, ethanol and glucose, over Fe-modified TiO2 is discussed. In particular, the influence of the reaction atmosphere (N2, air was investigated. Different gases were identified in the headspace volume of the reactor depending on the substrate. In general, the evolution of the gases was more effective in air compared to a N2 atmosphere. In the presence of air, the gaseous phase contained CO2, CH4 and H2, regardless of the substrate used. Moreover, formation of C2H6 and C3H8 in the case of acetic acid and C2H6 in the case of ethanol was observed. In case of acetic acid and methanol an increase in H2 evolution under aerated conditions was observed. It was concluded that the photocatalytic decomposition of organic compounds with simultaneous generation of combustible hydrocarbons and hydrogen could be a promising method of “green energy” production.

  7. The role of eggshell and underlying vitelline membrane for normal pattern formation in the early C. elegans embryo.

    Science.gov (United States)

    Schierenberg, Einhard; Junkersdorf, Bernd

    1992-12-01

    The embryo of the nematode Caenorhabditis elegans is surrounded by an inconspicuous inner vitelline membrane and a prominent outer chitinous eggshell proper. We demonstrate that the complete removal of the chitinous eggshell does not interfere with successful development to yield a normal worm. The same result can be obtained when the vitelline membrane is penetrated with laser microbeam irradiation of only the eggshell proper, gently enough to permit its resealing after a while. However, when large holes are made into the eggshell the concomitantly penetrated vitelline membrane does not reseal. While early development is quite normal under these conditions, gastrulation is defective in that gut precursor cells do not migrate in properly, eventually leading to embryonic arrest. This suggests a crucial role for pattern formation of the "micro-environment" around the embryo preserved by the intact vitelline membrane. Removing both eggshell and vitelline membrane results in a string-like arrangement of founder cells and subsequent grossly abnormal cell patterns. Our experiments support the idea that the prominent eggshell proper just functions as a mechanical protection while the thin vitelline membrane directly or indirectly serves as a necessary control element affecting the positions of cells which to begin with are determined by the orientation of the cleavage spindle.

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

    Directory of Open Access Journals (Sweden)

    Weini Huang

    2016-08-01

    Full Text Available 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.

  9. Numeracy as a precursor to pro-social behavior: The impact of numeracy and presentation format on the cognitive mechanisms underlying donation decisions

    Directory of Open Access Journals (Sweden)

    Stephan Dickert

    2011-10-01

    Full Text Available Donation requests often convey numerical information about the people in need. In two studies we investigated the effects of numeracy and presentation format on the underlying affective and cognitive mechanisms of donation decisions. In Study 1, participants were presented with information about a victim in need, either in a frequency format or in a percentage format. In Study 2, we manipulated the identifiability and number of target victims. Our results demonstrate that donations of individuals lower in numeracy were more susceptible to changes in numeric presentation format than those higher in numeracy. Importantly, the underlying mechanisms for donations differed by numeracy. Whereas the mental image of the victim influenced donation decisions of less numerate people only, the estimated impact of a donation was positively correlated with donation amounts for both more and less numerate individuals.

  10. Navigating Instructional Dialectics: Empirical Exploration of Paradox in Teaching

    Science.gov (United States)

    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…

  11. An Applet for the Investigation of Simpson's Paradox

    Science.gov (United States)

    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…

  12. TilE PARADOX OF PEDAGOGY TRANSPOSITION: Learning From ...

    African Journals Online (AJOL)

    TilE PARADOX OF PEDAGOGY TRANSPOSITION: Learning From Inhibitors to Teacher Change: Lessons from a Zimbabwean. Research Project in Environmental Education. Kathy Stiles. Definition of paradox used in this paper is "a person or thing conflicting with a preconceived notion of what is reasonable or possible" ...

  13. A paradox in the global description of the multiverse

    Energy Technology Data Exchange (ETDEWEB)

    Bousso, Raphael [Center for Theoretical Physics, Department of Physics, University of California, Berkeley, CA 94720-7300 (United States); Freivogel, Ben [Center for Theoretical Physics, Department of Physics, University of California, Berkeley, CA 94720-7300 (United States)

    2007-06-15

    We use an argument by Page to exhibit a paradox in the global description of the multiverse: the overwhelming majority of observers arise from quantum fluctuations and not by conventional evolution. Unless we are extremely atypical, this contradicts observation. The paradox does not arise in the local description of the multiverse, but similar arguments yield interesting constraints on the maximum lifetime of metastable vacua.

  14. Obesity paradox in patients undergoing coronary intervention: A review

    OpenAIRE

    Patel, Nirav; Elsaid, Ossama; Shenoy, Abhishek; Sharma, Abhishek; McFarlane, Samy I

    2017-01-01

    There is strong relationship exist between obesity and cardiovascular disease including coronary artery disease (CAD). However, better outcomes noted in obese patients undergoing percutaneous cardiovascular interventions for CAD, a phenomenon known as the obesity paradox. In this review, we performed extensive search for obesity paradox in obese patients undergoing percutaneous coronary intervention and discussed possible mechanism and disparities in different race and sex.

  15. Paradox and Double Binds in Adventure-Based Education.

    Science.gov (United States)

    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…

  16. The "Paradox of Interdisciplinarity" in Australian Research Governance

    Science.gov (United States)

    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…

  17. A Simple Explanation of the Classic Hydrostatic Paradox

    Science.gov (United States)

    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…

  18. A proof-theoretic account of the miners paradox

    Czech Academy of Sciences Publication Activity Database

    Klev, Ansten

    2016-01-01

    Roč. 82, č. 4 (2016), s. 351-369 ISSN 1755-2567 Institutional support: RVO:67985955 Keywords : miners paradox * proof theory * Ramsey conditionals * Fitch's Paradox Subject RIV: AA - Philosophy ; Religion http://onlinelibrary.wiley.com/doi/10.1111/theo.12090/full

  19. Paradoxes of functional neurosurgery: clues from basal ganglia recordings.

    Science.gov (United States)

    Brown, Peter; Eusebio, Alexandre

    2008-01-01

    Deep brain stimulation (DBS) can be remarkably effective in treating movement disorders such as Parkinson's disease, dystonia, and essential tremor. Yet these effects remain essentially unexplained, even paradoxical. Equally challenging is the fact that DBS of motor targets in the basal ganglia appears to reverse abnormalities of movement without any obvious deleterious effects on remaining aspects of movement. Here, we explore the extent to which the noisy signal hypothesis might help solve some of these apparent paradoxes. Essentially the hypothesis, first tentatively advanced by Marsden and Obeso (1994), suggests that disease leads to a pattern of basal ganglia activity that disrupts local and distant function and that surgery acts to suppress or override this noisy signal. Critical to the success this theory is that different disease phenotypes are associated with different patterns of noisy signal, and we survey the evidence to support this contention, with specific emphasis on different types of pathological synchronization. However, just as DBS may suppress or override noisy signals in the basal ganglia, it must equally antagonize any remaining physiological functioning in these key motor structures. We argue that the latter effect of DBS becomes manifest when baseline motor performance is relatively preserved, i.e., when pathological activity is limited. Under these circumstances, the deleterious effects of DBS are no longer obscured by its therapeutic actions in suppressing noisy signals. Whether true, oversimplified or simply incorrect, the noisy signal hypothesis has served to focus attention on the detailed character of basal ganglia discharge and its variation with disease and therapy. 2007 Movement Disorder Society

  20. Indian paradox: Rising education, declining womens' employment

    Directory of Open Access Journals (Sweden)

    Esha Chatterjee

    2018-03-01

    Full Text Available Background: Theories of human capital would suggest that with more education, women acquire greater skills and their earnings increase, resulting in higher labor force participation. However, it has been long known that in India, women's education has a U-shaped relationship with labor force participation. Part of the decline at moderate levels of education may be due to an income effect whereby women with more education marry into richer families that enable them to withdraw from the labor force. Objective: The paper uses the first comprehensive Indian income data to evaluate whether the other family income effect explains the negative relationship between moderate women's education and their labor force participation. Methods: Using two waves of the India Human Development Survey, a comprehensive measure of labor force participation is regressed on educational levels for currently married women aged 25-59. Results: We find a strong other family income effect that explains some but not all of the U-shape education relationship. Further analyses suggest the importance of a lack of suitable employment opportunities for moderately educated women. Conclusions: Other factors need to be identified to explain the paradoxical U-shape relationship. We suggest the importance of occupational sex segregation, which excludes moderately educated Indian women from clerical and sales jobs. Contribution: This paper provides a more definitive test of the other family income effect and identifies new directions for future research that might explain the paradoxical U-curve relationship.

  1. Birthday Paradox for Multi-Collisions

    Science.gov (United States)

    Suzuki, Kazuhiro; Tonien, Dongvu; Kurosawa, Kaoru; Toyota, Koji

    In this paper, we study multi-collision probability. For a hash function H:D→R with |R|=n, it has been believed that we can find an s-collision by hashing Q=n(s-1)/s times. We first show that this probability is at most 1/s! for any s, which is very small for large s. (for example, s=n(s-1)/s) Thus the above folklore is wrong for large s. We next show that if s is small, so that we can assume Q-s≈Q, then this probability is at least 1/s!-1/2(s!)2, which is very high for small s (for example, s is a constant). Thus the above folklore is true for small s. Moreover, we show that by hashing (s!)1/s×Q+s-1(≤n) times, an s-collision is found with probability approximately 0.5 for any n and s such that (s!/n)1/s≈0. Note that if s=2, it coincides with the usual birthday paradox. Hence it is a generalization of the birthday paradox to multi-collisions.

  2. Fermi's Paradox - The Last Challenge For Copernicanism?

    Directory of Open Access Journals (Sweden)

    Ćirković, M. M.

    2009-06-01

    Full Text Available We review Fermi's paradox (or the "Great Silence" problem, not only arguably the oldest and crucial problem for the Search for ExtraTerrestrial Intelligence (SETI, but also a conundrum of profound scientific, philosophical and cultural importance. By a simple analysis of observation selection effects, the correct resolution of Fermi's paradox is certain to tell us something about the future of humanity. Already more than three quarters of century old puzzle -- and a quarter of century since the last major review paper in the field by G. David Brin -- has generated many ingenious discussions and hypotheses. We analyze the often tacit methodological assumptions built in various answers to this puzzle and attempt a new classification of the numerous solutions proposed in an already huge literatureon the subject. Finally, we consider the ramifications of variousclasses of hypotheses for the practical SETI projects. Somewhatparadoxically, it seems that the class of (neocatastrophichypotheses gives, on the balance, the strongest justification tooptimism regarding our current and near-future SETI efforts.

  3. The Obesity Paradox and Cardiorespiratory Fitness

    Directory of Open Access Journals (Sweden)

    Paul A. McAuley

    2012-01-01

    Full Text Available Cardiorespiratory fitness as an explanation for the obesity paradox warrants further examination. We evaluated independent and joint associations of cardiorespiratory fitness and adiposity with all-cause mortality in 811 middle-aged (age, 53.3±7.2 years male never smokers without documented cardiopulmonary disease or diabetes from the Veterans Exercise Testing Study (VETS. Cardiorespiratory fitness was quantified in metabolic equivalents (METs using final treadmill speed and grade achieved on a maximal exercise test. Subjects were grouped for analysis by METs: unfit (lowest third and fit (upper two-thirds; and by body mass index (kg/m2: nonobese (18.5−29.9 and obese (≥30.0. Associations of baseline fitness and adiposity measures with all-cause mortality were determined by Cox proportional hazards analysis adjusted for age, ethnicity, hypertension, hypercholesterolemia, family history of coronary artery disease, and cardiovascular medication use. In multivariate analysis, mortality risk for obese/fit men did not differ significantly from the nonobese/fit reference group. However, compared to the reference group, nonobese and obese unfit men were 2.2 (=0.01 and 1.9 (=0.03 times more likely to die, respectively. Cardiorespiratory fitness altered the obesity paradox such that mortality risk was lower for both obese and nonobese men who were fit.

  4. Climate paradox of the G-8: legal obligations, policy declarations and implementation gap

    Directory of Open Access Journals (Sweden)

    Hans Guenter Brauch

    2012-01-01

    Full Text Available This article analyzes the climate policy performance of the G-8 from 1992 to 2012 based on their legal commitments (Annex-1 and Annex-B countries under the UNFCCC (1992 and the Kyoto Protocol (1997 and their policy declarations on their GHG reduction goals until 2050. A climate paradox has emerged due to a growing implementation gap in Canada, USA and Japan, while Russia, Germany, UK, France and Italy fulfilled their GHG reduction obligation.

  5. Geochemical characterisation of kerogen from the Boom Clay Formation (Mol, Belgium) and evolution under different thermal stress

    International Nuclear Information System (INIS)

    Deniau, I.

    2002-12-01

    The Boom clay formation in Belgium has been chosen as test site for the disposal of high level radioactive wastes. The organic matter present in the clay (kerogen) is sensible to the thermal stress and can generate a huge number of gaseous and liquid compounds leading to local pH changes and to fracturing processes. In particular, some polar compounds can complex radionuclides. The samples analyzed in this work were taken in the underground laboratory of Mol at a 223 m depth. They have been analyzed in detail using geochemical methods (Rock-Eval pyrolysis, element analysis, transmission and scanning electron microscopy), spectroscopic methods (Fourier transformation infrared spectroscopy, solid state 13 C NMR, Raman) and pyrolytic methods (off-line, on-line and in sealed tubes combined with coupled CG/SM analyses). The study of a representative sample of this formation has permitted to characterize the organic matter at the molecular scale, to determine its fossilization mechanisms and the nature of the organic compounds trapped inside the kerogen. The organic matter of the Boom clays comes mainly from phyto-planktonic matter with an important contribution of terrestrial and bacterial matter. The degradation-recondensation played an important role in its preservation but the presence of numerous oxygenated molecules implies that oxidative incorporation also participated to this preservation. Finally, various products (hydrocarbons, oxygenated and nitrogenous polar compounds) trapped in significant amount inside the macro-molecular structure are released under a relatively weak thermal stress. Moreover several small polar organic molecules are released and can play a significant role in the retention or migration of radionuclides inside the geologic barrier. A sample submitted to a in-situ thermal stress of 80 deg. C during 5 years (Cerberus experiment) do not show any significant change in its kerogen structure with respect to the non-heated reference sample

  6. Inhibition of Hb Binding to GP1bα Abrogates Hb-Mediated Thrombus Formation on Immobilized VWF and Collagen under Physiological Shear Stress.

    Science.gov (United States)

    Annarapu, Gowtham K; Singhal, Rashi; Peng, Yuandong; Guchhait, Prasenjit

    2016-01-01

    Reports including our own describe that intravascular hemolysis increases the risk of thrombosis in hemolytic disorders. Our recent study shows that plasma Hb concentrations correlate directly with platelet activation in patients with paroxysmal nocturnal hemoglobinuria (PNH). The binding of Hb to glycoprotein1bα (GP1bα) increases platelet activation. A peptide AA1-50, designed from N-terminal amino acid sequence of GP1bα significantly inhibits the Hb binding to GP1bα as well as Hb-induced platelet activation. This study further examined if the Hb-mediated platelet activation plays any significant role in thrombus formation on subendothelium matrix under physiological flow shear stresses and the inhibition of Hb-platelet interaction can abrogate the above effects of Hb. Study performed thrombus formation assay in vitro by perfusing whole blood over immobilized VWF or collagen type I in presence of Hb under shear stresses simulating arterial or venous flow. The Hb concentrations ranging from 5 to 10 μM, commonly observed level in plasma of the hemolytic patients including PNH, dose-dependently increased thrombus formation on immobilized VWF under higher shear stress of 25 dyne/cm2, but not at 5 dyne/cm2. The above Hb concentrations also increased thrombus formation on immobilized collagen under both shear stresses of 5 and 25 dyne/cm2. The peptide AA1-50 abrogated invariably the above effects of Hb on thrombus formation. This study therefore indicates that the Hb-induced platelet activation plays a crucial role in thrombus formation on immobilized VWF or collagen under physiological flow shear stresses. Thus suggesting a probable role of this mechanism in facilitating thrombosis under hemolytic conditions.

  7. The effect of pre-plasma formation under nonlocal transport conditions for ultra-relativistic laser-plasma interaction

    Science.gov (United States)

    Holec, M.; Nikl, J.; Vranic, M.; Weber, S.

    2018-04-01

    Interaction of high-power lasers with solid targets is in general strongly affected by the limited contrast available. The laser pre-pulse ionizes the target and produces a pre-plasma which can strongly modify the interaction of the main part of the laser pulse with the target. This is of particular importance for future experiments which will use laser intensities above 1021 W cm-2 and which are subject to the limited contrast. As a consequence the main part of the laser pulse will be modified while traversing the pre-plasma, interacting with it partially. A further complication arises from the fact that the interaction of a high-power pre-pulse with solid targets very often takes place under nonlocal transport conditions, i.e. the characteristic mean-free-path of the particles and photons is larger than the characteristic scale-lengths of density and temperature. The classical diffusion treatment of radiation and heat transport in the hydrodynamic model is then insufficient for the description of the pre-pulse physics. These phenomena also strongly modify the formation of the pre-plasma which in turn affects the propagation of the main laser pulse. In this paper nonlocal radiation-hydrodynamic simulations are carried out and serve as input for subsequent kinetic simulations of ultra-high intensity laser pulses interacting with the plasma in the ultra-relativistic regime. It is shown that the results of the kinetic simulations differ considerably whether a diffusive or nonlocal transport is used for the radiation-hydrodynamic simulations.

  8. The effects of synthesis parameters on the formation of PbI2 particles under DTAB-assisted hydrothermal process

    International Nuclear Information System (INIS)

    Zhu Gangqiang; Hojamberdiev, Mirabbos; Liu Peng; Peng Jianhong; Zhou Jianping; Bian Xiaobin; Huang Xijin

    2011-01-01

    Highlights: ► Submicron- and micron-sized PbI 2 particles were hydrothermally synthesized. ► Structural transformation form belt-like to rod- and microtube-like was observed. ► Phase-pure PbI 2 particles could be hydrothermally obtained at pH 2 particles. ► The optical band gap energy of PbI 2 was slightly affected by morphology. - Abstract: Submicron- and micron-sized lead iodide (PbI 2 ) particles with well-controlled morphologies were successfully fabricated via a low-temperature hydrothermal process assisted by dodecyltrimethylammonium bromide (DTAB) as cationic surfactant. The as-synthesized powders were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and UV–vis spectroscopy. The effects of synthesis parameters (temperature, time, pH, and surfactant amount) were systematically investigated. The obtained results showed that the submicron structure was belt-like at 100–120 °C, transformed to rod-like by increasing temperature to 140 °C and it became a microtube-like at 160–200 °C. By changing the pH of the synthesizing solution, it was found that a pure PbI 2 phase could be obtained below 7. With the addition of increasing amount of surfactant, microparticles were converted to microrods → submicron belts → microtubes. The time-dependent experimental results revealed that the dissolution–recrystallization and dissolution–recrystallization–self-oriented-attachment were considered to be the possible mechanisms for the formation of the belt- and tube-like PbI 2 submicron- and micron-sized particles, respectively. The optical properties of the PbI 2 particles synthesized at 100–200 °C for 8 h under hydrothermal conditions were also studied.

  9. Intragastric formation and modulation of N-nitrosodimethylamine in a dynamic in vitro gastrointestinal model under human physiological conditions

    NARCIS (Netherlands)

    Krul, C.A.M.; Zeilmaker, M.J.; Schothorst, R.C.; Havenaar, R.

    2004-01-01

    Human exposure to carcinogenic N-alkylnitrosamines can occur exogenously via food consumption or endogenously by formation of these compounds through nitrosation of amine precursors. Information on the intragastric formation of NDMA from complex mixtures of precursors and inhibitors in humans is not

  10. A Paradoxical Intention: A Brief Description of a Cognitive Behaviour Therapy Approach and Its Potential for Counselling.

    Science.gov (United States)

    Athanasou, James A.

    Techniques of cognitive behavior modification such as cognitive restructuring have recently been employed in behavior therapy. Other procedures which fall within the approach of cognitive behavior therapy are techniques such as paradoxical intention which are subsumed under the title of logotherapy. Logotherapy refers to a form of psychotherapy or…

  11. Comment on "Clouds and the Faint Young Sun Paradox" by Goldblatt and Zahnle (2011

    Directory of Open Access Journals (Sweden)

    R. Rondanelli

    2012-03-01

    Full Text Available Goldblatt and Zahnle (2011 raise a number of issues related to the possibility that cirrus clouds can provide a solution to the faint young sun paradox. Here, we argue that: (1 climates having a lower than present mean surface temperature cannot be discarded as solutions to the faint young sun paradox, (2 the detrainment from deep convective clouds in the tropics is a well-established physical mechanism for the formation of high clouds that have a positive radiative forcing (even if the possible role of these clouds as a negative climate feedback remains controversial and (3 even if some cloud properties are not mutually consistent with observations in radiative transfer parameterizations, the most relevant consistency (for the purpose of hypothesis testing is with observations of the cloud radiative forcing. Therefore, we maintain that cirrus clouds, as observed in the current climate and covering a large region of the tropics, can provide a solution to the faint young sun paradox, or at least ease the amount of CO2 or other greenhouse substances needed to provide temperatures above freezing during the Archean.

  12. Soil formation.

    NARCIS (Netherlands)

    Breemen, van N.; Buurman, P.

    1998-01-01

    Soil Formation deals with qualitative and quantitative aspects of soil formation (or pedogenesis) and the underlying chemical, biological, and physical processes. The starting point of the text is the process - and not soil classification. Effects of weathering and new formation of minerals,

  13. The periodontal pain paradox: Difficulty on pain assesment in dental patients (The periodontal pain paradox hypothesis

    Directory of Open Access Journals (Sweden)

    Haryono Utomo

    2006-12-01

    Full Text Available In daily dental practice, the majority of patients’ main complaints are related to pain. Most patients assume that all pains inside the oral cavity originated from the tooth. One particular case is thermal sensitivity; sometimes patients were being able to point the site of pain, although there is neither visible caries nor secondary caries in dental radiograph. In this case, gingival recession and dentin hypersensitivity are first to be treated to eliminate the pain. If these treatments failed, pain may misdiagnose as pulpal inflammation and lead to unnecessary root canal treatment. Study in pain during periodontal instrumentation of plaque-related periodontitis revealed that the majority of patients feel pain and discomfort during probing and scaling. It seems obvious because an inflammation, either acute or chronic is related to a lowered pain threshold. However, in contrast, in this case report, patient suffered from chronic gingivitis and thermal sensitivity experienced a relative pain-free sensation during probing and scaling. Lowered pain threshold which accompanied by a blunted pain perception upon periodontal instrumentation is proposed to be termed as the periodontal pain paradox. The objective of this study is to reveal the possibility of certain factors in periodontal inflammation which may involved in the periodontal pain paradox hypothesis. Patient with thermal hypersensitivity who was conducted probing and scaling, after the relative pain-free instrumentation, thermal hypersensitivity rapidly disappeared. Based on the successful periodontal treatment, it is concluded that chronic gingivitis may modulate periodontal pain perception which termed as periodontal pain paradox

  14. Cannabinoid Hyperemesis Syndrome: A Paradoxical Cannabis Effect

    Directory of Open Access Journals (Sweden)

    Ivonne Marie Figueroa-Rivera

    2015-01-01

    Full Text Available Despite well-established antiemetic properties of marijuana, there has been increasing evidence of a paradoxical effect in the gastrointestinal tract and central nervous system, given rise to a new and underrecognized clinical entity called the Cannabinoid Hyperemesis Syndrome. Reported cases in the medical literature have established a series of patients exhibiting a classical triad of symptoms: cyclic vomiting, chronic marijuana use, and compulsive bathing. We present a case of a 29-year-old man whose clinical presentation strongly correlates with cannabinoid hyperemesis syndrome. Despite a diagnosis of exclusion, this syndrome should be considered plausible in the setting of a patient with recurrent intractable vomiting and a strong history of cannabis use as presented in this case.

  15. [Euthanasia and the paradoxes of autonomy].

    Science.gov (United States)

    Siqueira-Batista, Rodrigo; Schramm, Fermin Roland

    2008-01-01

    The principle of respect for autonomy has proved very useful for bioethical arguments in favor of euthanasia. However unquestionable its theoretical efficacy, countless aporiae can be raised when conducting a detailed analysis of this concept, probably checkmating it. Based on such considerations, this paper investigates the principle of autonomy, starting with its origins in Greek and Christian traditions, and then charting some of its developments in Western cultures through to its modern formulation, a legacy of Immanuel Kant. The main paradoxes of this concept are then presented in the fields of philosophy, biology, psychoanalysis and politics, expounding several of the theoretical difficulties to be faced in order to make its applicability possible within the scope of decisions relating to the termination of life.

  16. Partial Actions, Paradoxicality and Topological full Groups

    DEFF Research Database (Denmark)

    Scarparo, Eduardo

    uniform Roe algebra is finite. In Article C, we analyze the C*-algebra generated by the Koopman representation of a topological full group, showing, in particular, that it is not AF andhas real rank zero. We also prove that if G is a finitely generated, elementary amenable group, and C*(G) has real rank......We study how paradoxicality properties affect the way groups partially acton topological spaces and C*-algebras. We also investigate the real rank zero and AF properties for certain classes of group C*-algebras. Specifically, in article A, we characterize supramenable groups in terms of existence...... of invariant probability measures for partial actions on compact Hausdorff spaces and existence of tracial states on partial crossed products. These characterizations show that, in general, one cannot decompose a partial crossed product of a C*-algebra by a semidirect product of groups as two iterated...

  17. The paradoxes of small Public Private Partnerships

    DEFF Research Database (Denmark)

    Koch, Christian; Jensen, Jesper Ole

    not through databases containing data on realized PPP-s possible to find any lower limit for these established PPPs. This apparent paradox is then qualitatively investigated. Are these small PPP really full blown PPP? It is investigated whether the PPP are really Design, Build, Finance and Operate project......It is commonly assumed that transaction costs linked to the establishment of Public Private Partnerships (PPP), make it prohibitive to make them too small. In a Danish context this has been safeguarded by the authorities, which recommend sizes over 13, 4 million euro (100 million euro......). The research behind this paper sets out the challenge this size limit. The paper present quantitative and qualitative material on small PPP on the Italian and British real estate market. It is shown that small PPP (below 13,4 million euro) are widespread in the two investigated countries. It is thus...

  18. Paradoxes and Opportunities in Logistic Outsourcing Research

    Directory of Open Access Journals (Sweden)

    Đurđica Stojanović

    2012-11-01

    Full Text Available Historically, very few logistic trends have caught the attention of academics and practitioners to the same extent as outsourcing. A comprehensive literature review reveals two reasons for this continual topicality. The problem complexity and the business environment dynamics – including an interaction with other main trends in logistics and modern supply chains – both led to a permanent literature gap, indicating the need to explore some new aspects of logistics outsourcing (LO. In this paper, a new LO research perspective has been explored by identifying some weaknesses in the main LO research streams and related common viewpoints which led to six ‘logistics outsourcing research paradoxes’. Each of these paradoxes is briefly described and their links with research streams and common views on LO discussed. Finally, the nature of some known opportunities for further research is better explained and some overlooked research opportunities are highlighted.

  19. Paradoxes of reading and knowledge in Slovenia

    Directory of Open Access Journals (Sweden)

    Miha Kovač

    2009-01-01

    Full Text Available The paper introduces the concept of book usage and puts Slovenian book usage into the context of the European Union. It stresses the limits of European book statistics,due to them the measurements of book usage in various European societies is almost impossible. In this context, we will show that due to available data, Slovenia paradoxically belongs to the countries with high book usage and average reading habits. In the second part of the paper, we will look at the correlations between reading habits and efficiency of education systems. On this basis, we will ask some new questions and develop a set of hypotheses that need to be verified by the further research.

  20. Paradoxical reactions in children with tuberculosis.

    Science.gov (United States)

    Shah, Ira; Bhaskar, M V

    2017-04-01

    We sought to determine the incidence and clinical spectrum of the paradoxical reaction (PR) to treatment in 1000 children with tuberculosis (TB). Its incidence was 3.3%, presenting as mediastinal adenopathy (n = 12), central nervous system (CNS) tuberculoma (n = 8), increasing size of lymph nodes (n = 8) and serositis (n = 5). Symptoms included breathlessness (n = 7, 21.2%), neck swellings (n = 5, 15.2%), hemiplegia (n = 3, 9.1%), raised intracranial tension (n = 2, 6.1%) and fever or diabetes insipidus (n = 1, 3% each). The mean age of onset of PR was 3.5 months after the start of anti-TB medication. PR was seen predominantly in boys. Mediastinal lymphadenopathy was more common in children aged children aged 2-5 years. Nodal enlargement and serositis were seen equally in all age groups.

  1. Cosmic time dilation: The clock paradox revisited

    International Nuclear Information System (INIS)

    Tomaschitz, Roman

    2004-01-01

    The relativistic time dilation is reviewed in a cosmological context. We show that a clock or twin paradox does not arise if cosmic time is properly taken into account. The receding galaxy background provides a unique frame of reference, and the proper times of geodesic as well as accelerated observers can be linked to the universal cosmic time parameter. This suggests to compare the proper time differentials of the respective observers by determining their state of motion in the galaxy grid. In this way, each observer can figure out whether his proper time is dilated or contracted relative to any other. In particular one can come to unambiguous conclusions on the aging of uniformly moving observers, without reference to asymmetries in measurement procedures or accelerations they may have undergone

  2. First status report on regional ground-water flow modeling for the Paradox Basin, Utah

    International Nuclear Information System (INIS)

    Andrews, R.W.

    1984-05-01

    Regional ground-water flow within the principal hydrogeologic units of the Paradox Basin is evaluated by developing a conceptual model of the flow regime in the shallow aquifers and the deep-basin brine aquifers and testing these models using a three-dimensional, finite-difference flow code. Semiquantitative sensitivity analysis (a limited parametric study) is conducted to define the system response to changes in hydrologic properties or boundary conditions. A direct method for sensitivity analysis using an adjoint form of the flow equation is applied to the conceptualized flow regime in the Leadville limestone aquifer. All steps leading to the final results and conclusions are incorporated in this report. The available data utilized in this study is summarized. The specific conceptual models, defining the areal and vertical averaging of litho-logic units, aquifer properties, fluid properties, and hydrologic boundary conditions, are described in detail. Two models were evaluated in this study: a regional model encompassing the hydrogeologic units above and below the Paradox Formation/Hermosa Group and a refined scale model which incorporated only the post Paradox strata. The results are delineated by the simulated potentiometric surfaces and tables summarizing areal and vertical boundary fluxes, Darcy velocities at specific points, and ground-water travel paths. Results from the adjoint sensitivity analysis include importance functions and sensitivity coefficients, using heads or the average Darcy velocities to represent system response. The reported work is the first stage of an ongoing evaluation of the Gibson Dome area within the Paradox Basin as a potential repository for high-level radioactive wastes

  3. Simpson’s Paradox in Psychological Science: A Practical Guide

    Directory of Open Access Journals (Sweden)

    Rogier eKievit

    2013-08-01

    Full Text Available 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 drawing on empirical results from cognitive neuroscience, behavior genetics, psychopathology, 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.

  4. The Epigenetic Paradox of Pluripotent ES Cells.

    Science.gov (United States)

    Festuccia, Nicola; Gonzalez, Inma; Navarro, Pablo

    2017-05-19

    The propagation and maintenance of gene expression programs are at the foundation of the preservation of cell identity. A large and complex set of epigenetic mechanisms enables the long-term stability and inheritance of transcription states. A key property of authentic epigenetic regulation is being independent from the instructive signals used for its establishment. This makes epigenetic regulation, particularly epigenetic silencing, extremely robust and powerful to lock regulatory states and stabilise cell identity. In line with this, the establishment of epigenetic silencing during development restricts cell potency and maintains the cell fate choices made by transcription factors (TFs). However, how more immature cells that have not yet established their definitive fate maintain their transitory identity without compromising their responsiveness to signalling cues remains unclear. A paradigmatic example is provided by pluripotent embryonic stem (ES) cells derived from a transient population of cells of the blastocyst. Here, we argue that ES cells represent an interesting "epigenetic paradox": even though they are captured in a self-renewing state characterised by extremely efficient maintenance of their identity, which is a typical manifestation of robust epigenetic regulation, they seem not to heavily rely on classical epigenetic mechanisms. Indeed, self-renewal strictly depends on the TFs that previously instructed their undifferentiated identity and relies on a particular signalling-dependent chromatin state where repressive chromatin marks play minor roles. Although this "epigenetic paradox" may underlie their exquisite responsiveness to developmental cues, it suggests that alternative mechanisms to faithfully propagate gene regulatory states might be prevalent in ES cells. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  5. A medical paradox: curative versus preventive medicine.

    Science.gov (United States)

    Brock, J F

    1976-08-07

    A familiar medical contrast is presented as part of a modern medical problem. The problem it reflects is the relative importance of preventive and curative services for medical practitioners, which is already, or will shortly resolve itself into, a dilemma of whether medical men should stress preventive medicine to the possible detriment of curative medicine. It is submitted that the solution to both problem and dilemma should be sought against the background of history and philosophy, where they are seen to be expressions of an eternal paradox--that of the relative value of the individual in relation to the family, group, or community. If the submission is valid, then the answer to the problem is not a purely medical exercise, nor is the dilemma purely a 'doctor's dilemma'. The paradox, being eternal, is not soluble in our time, but the community must, on the urging of the medical profession, find a general solution to the problem--'a public consensus for out time'. This must be followed by public demand for a parliamentary solution--'decision-making ex consensus'. It is argued that although the latter programme does not come easily to democracy, it can be achieved through public consensus if action is taken by the leaders of thought in appropriate categories. Initiative must be exercised by the medical profession, but public consensus can only be achieved in consultation with the leaders of all learned professions, civil servants and legislators. It must then be presented fairly and without bias to the public. In the meantime, the medical profession must formulate its own 'medical consensus' and the doctor must resolve his personal dilemma according to formulated law, public or medical consensus or, in the last resort, according to his conviction and conscience. This method of solving a problem will almost certainly be applicable to other and more recent medical problems such as the population explosion, selective abortion and euthanasia.

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

    Science.gov (United States)

    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.

  7. EPR paradox, quantum nonlocality and physical reality

    Science.gov (United States)

    Kupczynski, M.

    2016-03-01

    Eighty years ago Einstein, Podolsky and Rosen demonstrated that instantaneous reduction of wave function, believed to describe completely a pair of entangled physical systems, led to EPR paradox. The paradox disappears in statistical interpretation of quantum mechanics (QM) according to which a wave function describes only an ensemble of identically prepared physical systems. QM predicts strong correlations between outcomes of measurements performed on different members of EPR pairs in far-away locations. Searching for an intuitive explanation of these correlations John Bell analysed so called local realistic hidden variable models and proved that correlations consistent with these models satisfy Bell inequalities which are violated by some predictions of QM and by experimental data. Several different local models were constructed and inequalities proven. Some eminent physicists concluded that Nature is definitely nonlocal and that it is acting according to a law of nonlocal randomness. According to these law perfectly random, but strongly correlated events, can be produced at the same time in far away locations and a local and causal explanation of their occurrence cannot be given. We strongly disagree with this conclusion and we prove the contrary by analysing in detail some influential finite sample proofs of Bell and CHSH inequalities and so called Quantum Randi Challenges. We also show how one can win so called Bell's game without violating locality of Nature. Nonlocal randomness is inconsistent with local quantum field theory, with standard model in elementary particle physics and with causal laws and adaptive dynamics prevailing in the surrounding us world. The experimental violation of Bell-type inequalities does not prove the nonlocality of Nature but it only confirms a contextual character of quantum observables and gives a strong argument against counterfactual definiteness and against a point of view according to which experimental outcomes are produced

  8. A "refugee paradox" for substance use disorders?

    Science.gov (United States)

    Salas-Wright, Christopher P; Vaughn, Michael G

    2014-09-01

    Few, if any, studies have systematically examined the link between nativity and substance use disorders (SUD) among refugees using national samples. As such, it remains uncertain if the "immigrant paradox" for substance use can be extended to include refugees in the United States. Employing data from the National Epidemiologic Survey on Alcohol and Related Conditions, we examine the lifetime prevalence of SUDs among refugees (n=428) in contrast with non-refugee immigrants (n=4955) and native-born Americans (n=29,267). We also examine the impact of gender and refugee duration on the relationship between nativity, refugee status, and SUDs. Refugees were between 3 and 6 times less likely than native-born Americans meet criteria for all SUDs examined, and significantly less likely than non-refugee immigrants to meet criteria for alcohol (AOR=0.44, 95% CI=0.41-0.47), cocaine (AOR=0.54, 95% CI=0.50-0.59), hallucinogen (AOR=0.66, 95% CI=0.58-0.74), and opioid/heroin (AOR=0.62, 95% CI=0.58-0.66) use disorders. The refugee-SUD link was significantly moderated by gender. Duration as a refugee was associated with increased risk for alcohol use disorder and decreased risk of cannabis and illicit drug use disorders. Study findings provide evidence in support of a "refugee paradox" for SUDs among adults in the United States. Refugees are substantially less likely than native-born Americans to meet criteria for all SUDs examined and, albeit with weaker effects, significantly less likely than non-refugee immigrants to meet criteria for a variety of SUDs. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  9. Airborne electromagnetic and magnetic survey data of the Paradox and San Luis Valleys, Colorado

    Science.gov (United States)

    Ball, Lyndsay B.; Bloss, Benjamin R.; Bedrosian, Paul A.; Grauch, V.J.S.; Smith, Bruce D.

    2015-01-01

    In October 2011, the U.S. Geological Survey (USGS) contracted airborne magnetic and electromagnetic surveys of the Paradox and San Luis Valleys in southern Colorado, United States. These airborne geophysical surveys provide high-resolution and spatially comprehensive datasets characterizing the resistivity structure of the shallow subsurface of each survey region, accompanied by magnetic-field information over matching areas. These data were collected to provide insight into the distribution of groundwater brine in the Paradox Valley, the extent of clay aquitards in the San Luis Valley, and to improve our understanding of the geologic framework for both regions. This report describes these contracted surveys and releases digital data supplied under contract to the USGS.

  10. On the formation of nanostructures on a CdTe surface, stimulated by surface acoustic waves under nanosecond laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Vlasenko, A. I.; Baidullaeva, A.; Veleschuk, V. P., E-mail: vvvit@ukr.net; Mozol, P. E.; Boiko, N. I.; Litvin, O. S. [National Academy of Sciences of Ukraine, Lashkaryov Institute of Semiconductors Physics (Ukraine)

    2015-02-15

    The formation of nanoscale structures in the unirradiated part of a p-CdTe crystal surface irradiated by a nanosecond ruby laser is revealed and investigated. It is shown that their formation is caused by the effect of the long-range action of a laser pulse with an intensity of I = 20 MW/cm{sup 2}. Nanoscale-structure formation is explained by the influence of the pressure gradient of the surface acoustic wave, in particular, within the “vacancy-pump” mechanism on the surface.

  11. Formation of Nanodroplets in N2/H2O/SO2 under Irradiation of Fast Proton Beams

    DEFF Research Database (Denmark)

    Nakai, Youchi; Shigeoka, Tomita; Funada, Shuhei

    The droplet formation induced by cosmic ray in the terrestrial atmosphere attract certainattention in recent decades because this process could be important to understand thepossible relationship between cosmic ray and climate on the earth. The role of energetic ionsfor the droplet formation would...... measured with adifferential mobility analyzer. We found that the mass yield of generated droplets showedlinear dependence on the amount of SO2 oxidation. This behavior is different from binarynucleation theory of water and H2SO4. The difference might indicates importance ofconsidering the droplet formation...

  12. [Impact of biologically important anions on reactive oxygen species formation in water under the effect of non-ionizing physical agents].

    Science.gov (United States)

    Gudkov, S V; Ivanov, V E; Karp, O É; Chernikov, A V; Belosludtsev, K N; Bobylev, A G; Astashev, M E; Gapeev, A B; Bruskov, V I

    2014-01-01

    The influence of biologically relevant anions (succinate, acetate, citrate, chloride, bicarbonate, hydroorthophosphate, dihydroorthophosphate, nitrite, nitrate) on the formation of hydrogen peroxide and hydroxyl radicals in water was studied under the effect of non-ionizing radiation: heat, laser light with a wavelength of 632.8 nm, corresponding to the maximum absorption of molecular oxygen, and electromagnetic radiation of extremely high frequencies. It has been established that various anions may both inhibit the formation of reactive oxygen species and increase it. Bicarbonate and sulfate anions included in the biological fluids' and medicinal mineral waters have significant, but opposite effects on reactive oxygen species production. Different molecular mechanisms of reactive oxygen species formation are considered under the action of the investigated physical factors involving these anions, which may influence the biological processes by signal-regulatory manner and provide a healing effect in physical therapy.

  13. Effects of behavioral patterns and network topology structures on Parrondo’s paradox

    Science.gov (United States)

    Ye, Ye; Cheong, Kang Hao; Cen, Yu-Wan; Xie, Neng-Gang

    2016-11-01

    A multi-agent Parrondo’s model based on complex networks is used in the current study. For Parrondo’s game A, the individual interaction can be categorized into five types of behavioral patterns: the Matthew effect, harmony, cooperation, poor-competition-rich-cooperation and a random mode. The parameter space of Parrondo’s paradox pertaining to each behavioral pattern, and the gradual change of the parameter space from a two-dimensional lattice to a random network and from a random network to a scale-free network was analyzed. The simulation results suggest that the size of the region of the parameter space that elicits Parrondo’s paradox is positively correlated with the heterogeneity of the degree distribution of the network. For two distinct sets of probability parameters, the microcosmic reasons underlying the occurrence of the paradox under the scale-free network are elaborated. Common interaction mechanisms of the asymmetric structure of game B, behavioral patterns and network topology are also revealed.

  14. Effect of in situ hypothermic perfusion on intrahepatic pO(2) and reactive oxygen species formation after partial hepatectomy under total hepatic vascular exclusion in pigs

    NARCIS (Netherlands)

    Heijnen, Bob H. M.; Straatsburg, Irene H.; Kager, Liesbeth M.; van der Kleij, Ad J.; Gouma, Dirk J.; van Gulik, Thomas M.

    2003-01-01

    Aim: This study examined attenuation of ischemia and reperfusion (I/R) induced liver injury during liver resections by hypothermic perfusion of the liver under total hepatic vascular exclusion (THVE). Method: Reactive oxygen species (ROS) formation, microcirculatory integrity and endothelial cell

  15. Effect of small doses of ionizing radiation on motility, rosette formation, and antioxidant state of leukocytes under modification of G-proteins by cholera and pertussis toxins

    International Nuclear Information System (INIS)

    Zhirnov, V.V.; Luik, A.I.; Metelitsa, L.A.; Mogilevich, S.E.; Charochkina, L.L.

    2000-01-01

    The responses of motility and rosette formation of leukocytes to small radioactive doses (from 6 centre dot 10 -10 to 6 centre dot 10 -4 Gy) are studied. The influence of these doses on cell functions and oxidative homeostasis are investigated under the modification of transducing components of membrane signal pathways (adenylate cyclase and polyphosphoinositide cascades) with pertussis and cholera toxins

  16. Short communication: Roles of outer membrane protein W (OmpW) on survival and biofilm formation of Cronobacter sakazakii under neomycin sulfate stress.

    Science.gov (United States)

    Ye, Yingwang; Ling, Na; Gao, Jina; Zhang, Maofeng; Zhang, Xiyan; Tong, Liaowang; Ou, Dexin; Wang, Yaping; Zhang, Jumei; Wu, Qingping

    2018-04-01

    Cronobacter sakazakii is associated with severe infections including sepsis, neonatal meningitis, and necrotizing enterocolitis. Antibiotic resistance in Cronobacter species has been documented in recent years, but the genes involved in resistance in Cronobacter strains are poorly understood. In this study, we determined the role of outer membrane protein W (OmpW) on survival rates, morphologic changes, and biofilm formation between wild type (WT) and an OmpW mutant strain (ΔOmpW) under neomycin sulfate stress. Results indicated that the survival rates of ΔOmpW were significantly reduced after half minimum inhibitory concentration (½ MIC) treatment compared with the WT strain. Filamentation of C. sakazakii cells was observed after ½ MIC treatment in WT and ΔOmpW, and morphologic injury, including cell disruption and leakage of cells, was more predominant in ΔOmpW. Under ½ MIC stress, the biofilms of WT and ΔOmpW were significantly decreased, but decreasing rates of biofilm formation in mutant strain were more predominant compared with WT strain. This is the first report to determine the role of OmpW on survival, morphological changes, and biofilm formation in C. sakazakii under neomycin sulfate stress. The findings indicated that OmpW contributed to survival and reduction of morphological injury under neomycin sulfate stress. In addition, enhancing biofilm formation in ΔOmpW may be an alternative advantage for adaptation to neomycin sulfate stress. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  17. Topology Control Algorithms for Spacecraft Formation Flying Networks Under Connectivity and Time-Delay Constraints, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — SSCI is proposing to develop, test and deliver a set of topology control algorithms and software for a formation flying spacecraft that can be used to design and...

  18. The food-insecurity obesity paradox: A resource scarcity hypothesis.

    Science.gov (United States)

    Dhurandhar, Emily J

    2016-08-01

    Food insecurity is paradoxically associated with obesity in the United States. Current hypotheses to explain this phenomenon are descriptive regarding the low food security population's dietary and physical activity habits, but are not mechanistic. Herein it is proposed that a resource scarcity hypothesis may explain this paradox, such that fattening is a physiologically regulated response to threatened food supply that occurs specifically in low social status individuals. Evidence that this may be occurring, the implications for addressing the food insecurity-obesity paradox, and future areas of research, are reviewed and discussed. Copyright © 2016. Published by Elsevier Inc.

  19. Research regarding the formation of micropores in a Ni-Ti-C alloy during directional solidification under vacuum

    OpenAIRE

    Daoxin, J.; Lecomte-Beckers, Jacqueline

    1982-01-01

    The aim of this experiment was to study the origin and formation of microporosities in a Ni-5% Ti-0.2% C alloy which has been solidified and quenched, and to compare it to the previously developed mathematical model. In the selected alloy, the porosity may result from gases formed during solidification (for example by chemical reaction). The results show that solidification conditions influence microporosity formation through the fraction eutectic and this suggests that it is possible to rela...

  20. Reticular Formation Connections Underlying Horizontal Gaze: The Central Mesencephalic Reticular Formation (cMRF as a Conduit for the Collicular Saccade Signal

    Directory of Open Access Journals (Sweden)

    Paul J. May

    2017-04-01

    Full Text Available The central mesencephalic reticular formation (cMRF occupies much of the core of the midbrain tegmentum. Physiological studies indicate that it is involved in controlling gaze changes, particularly horizontal saccades. Anatomically, it receives input from the ipsilateral superior colliculus (SC and it has downstream projections to the brainstem, including the horizontal gaze center located in the paramedian pontine reticular formation (PPRF. Consequently, it has been hypothesized that the cMRF plays a role in the spatiotemporal transformation needed to convert spatially coded collicular saccade signals into the temporally coded signals utilized by the premotor neurons of the horizontal gaze center. In this study, we used neuroanatomical tracers to examine the patterns of connectivity of the cMRF in macaque monkeys in order to determine whether the circuit organization supports this hypothesis. Since stimulation of the cMRF produces contraversive horizontal saccades and stimulation of the horizontal gaze center produces ipsiversive saccades, this would require an excitatory cMRF projection to the contralateral PPRF. Injections of anterograde tracers into the cMRF did produce labeled terminals within the PPRF. However, the terminations were denser ipsilaterally. Since the PPRF located contralateral to the movement direction is generally considered to be silent during a horizontal saccade, we then tested the hypothesis that this ipsilateral reticuloreticular pathway might be inhibitory. The ultrastructure of ipsilateral terminals was heterogeneous, with some displaying more extensive postsynaptic densities than others. Postembedding immunohistochemistry for gamma-aminobutyric acid (GABA indicated that only a portion (35% of these cMRF terminals are GABAergic. Dual tracer experiments were undertaken to determine whether the SC provides input to cMRF reticuloreticular neurons projecting to the ipsilateral pons. Retrogradely labeled reticuloreticular

  1. Geochemistry and hydrodynamics of the Paradox Basin region, Utah, Colorado and New Mexico

    Science.gov (United States)

    Hanshaw, B.B.; Hill, G.A.

    1969-01-01

    The Paradox Basin region is approximately bounded by the south flank of the Uinta Basin to the north, the Uncompahgre uplift and San Juan Mountains to the east, the Four Corners structural platform to the southeast, the north rim of the Black Mesa Basin and the Grand Canyon to the south and southwest, and the Wasatch Plateau and Hurricane fault system to the west. Some of these geologic features are areas of ground-water recharge or discharge whereas others such as the Four Corners platform do not directly influence fluid movement. The aquifer systems studied were: (1) Mississippian rocks; (2) Pinkerton Trail Limestone of Wengerd and Strickland, 1954; (3) Paradox Member of the Hermosa Formation; (4) Honaker Trail Formation of Wengerd and Matheny, 1958; (5) Permian rocks. Recharge in the Paradox Basin occurs on the west flank of the San Juan Mountains and along the west side of the Uncompahgre uplift. The direction of ground-water movement in each analyzed unit is principally southwest-ward toward the topographically low outcrop areas along the Colorado River in Arizona. However, at any point in the basin, flow may be in some other direction owing to the influence of intrabasin recharge areas or local obstructions to flow, such as faults or dikes. A series of potentiometric surface maps was prepared for the five systems studied. Material used in construction of the maps included outcrop altitudes of springs and streams, drill-stem tests, water-well records, and an electric analog model of the entire basin. Many structurally and topographically high areas within the basin are above the regional potentiometric surface; recharge in these areas will drain rapidly off the high areas and adjust to the regional water level. With a few exceptions, most wells in formations above the Pennsylvanian contain fresh ( 35,000 mg/l T.D.S.) reported. Most water samples from strata below the Permian are brines of the sodium chloride type but with large amounts of calcium sulfate or

  2. Potential of select intermediate-volatility organic compounds and consumer products for secondary organic aerosol and ozone formation under relevant urban conditions

    Science.gov (United States)

    Li, Weihua; Li, Lijie; Chen, Chia-li; Kacarab, Mary; Peng, Weihan; Price, Derek; Xu, Jin; Cocker, David R.

    2018-04-01

    Emissions of certain low vapor pressure-volatile organic compounds (LVP-VOCs) are considered exempt to volatile organic compounds (VOC) regulations due to their low evaporation rates. However, these compounds may still play a role in ambient secondary organic aerosol (SOA) and ozone formation. The LVP-VOCs selected for this work are categorized as intermediate-volatility organic compounds (IVOCs) according to their vapor pressures and molecular formulas. In this study, the evaporation rates of 14 select IVOCs are investigated with half of them losing more than 95% of their mass in less than one month. Further, SOA and ozone formation are presented from 11 select IVOCs and 5 IVOC-containing generic consumer products under atmospherically relevant conditions using varying radical sources (NOx and/or H2O2) and a surrogate reactive organic gas (ROG) mixture. Benzyl alcohol (0.41), n-heptadecane (0.38), and diethylene glycol monobutyl ether (0.16) are determined to have SOA yields greater than 0.1 in the presence of NOx and a surrogate urban hydrocarbon mixture. IVOCs also influence ozone formation from the surrogate urban mixture by impacting radical levels and NOx availability. The addition of lab created generic consumer products has a weak influence on ozone formation from the surrogate mixture but strongly affects SOA formation. The overall SOA and ozone formation of the generic consumer products could not be explained solely by the results of the pure IVOC experiments.

  3. Recent Insights into the Paradoxical Effect of Echinocandins.

    Science.gov (United States)

    Wagener, Johannes; Loiko, Veronika

    2017-12-28

    Echinocandin antifungals represent one of the most important drug classes for the treatment of invasive fungal infections. The mode of action of the echinocandins relies on inhibition of the β-1,3-glucan synthase, an enzyme essentially required for the synthesis of the major fungal cell wall carbohydrate β-1,3-glucan. Depending on the species, echinocandins may exert fungicidal or fungistatic activity. Apparently independent of this differential activity, a surprising in vitro phenomenon called the "paradoxical effect" can be observed. The paradoxical effect is characterized by the ability of certain fungal isolates to reconstitute growth in the presence of higher echinocandin concentrations, while being fully susceptible at lower concentrations. The nature of the paradoxical effect is not fully understood and has been the focus of multiple studies in the last two decades. Here we concisely review the current literature and propose an updated model for the paradoxical effect, taking into account recent advances in the field.

  4. Paradoxical perception of surfaces in the Shepard tabletop illusion

    Science.gov (United States)

    Tyler, Christopher W

    2011-01-01

    The Shepard tabletop illusion, consisting of different perspective embeddings of two identical parallelograms as tabletops, affords a profound difference in their perceived surface shapes. My analysis reveals three further paradoxical aspects of this illusion, in addition to its susceptibility to the ‘inverse perspective illusion’ of the implied orthographic perspective of the table images. These novel aspects of the illusion are: a paradoxical slant of the tabletops, a paradoxical lack of perceived depth, and a paradoxical distortion of the length of the rear legs. The construction of the illusion resembles scenes found in ancient Chinese scroll paintings, and an analysis of the source of the third effect shows that the interpretation in terms of surfaces can account for the difference in treatment of the filled-in versus open forms in the Chinese painting from more than 1000 years ago. PMID:23145230

  5. One-Piece Faraday Generator: A Paradoxical Experiment from 1851

    Science.gov (United States)

    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)

  6. Living on the edge: contrasted wood-formation dynamics in Fagus sylvatica and Pinus sylvestris under Mediterranean conditions

    Directory of Open Access Journals (Sweden)

    Edurne eMartinez Del Castillo

    2016-03-01

    Full Text Available Wood formation in European beech (Fagus sylvatica L. and Scots pine (Pinus sylvestris L. was intra-annually monitored to examine plastic responses of the xylem phenology according to altitude in one of the southernmost areas of their distribution range, i.e. in the Moncayo Natural Park, Spain. The monitoring was done from 2011 to 2013 at 1180 and 1580 m a.s.l., corresponding to the lower and upper limits of European beech forest in this region. Microcores containing phloem, cambium and xylem were collected biweekly from twenty-four trees from the beginning of March to the end of November to assess the different phases of wood formation. The samples were prepared for light microscopy to observe the following phenological phases: onset and end of cell production, onset and end of secondary wall formation in xylem cells and onset of cell maturation. The temporal dynamics of wood formation widely differed among years, altitudes and tree species. For Fagus sylvatica, the onset of cambial activity varied between the first week of May and the third week of June. Cambial activity then slowed down and stopped in summer, resulting in a length of growing season of 48–75 days. In contrast, the growing season for Pinus sylvestris started earlier and cambium remained active in autumn, leading to a period of activity varying from 139-170 days. The intra-annual wood-formation pattern is site and species-specific. Comparison with other studies shows a clear latitudinal trend in the duration of wood formation, positive for Fagus sylvatica and negative for Pinus sylvestris.

  7. Rapid formation of nanocrystalline HfO2 powders from amorphous hafnium hydroxide under ultrasonically assisted hydrothermal treatment

    International Nuclear Information System (INIS)

    Meskin, Pavel E.; Sharikov, Felix Yu.; Ivanov, Vladimir K.; Churagulov, Bulat R.; Tretyakov, Yury D.

    2007-01-01

    Peculiarities of hafnium hydroxide hydrothermal decomposition were studied by in situ heat flux calorimetry for the first time. It was shown that this process occurs in one exothermal stage (ΔH = -17.95 kJ mol -1 ) at 180-250 deg. C resulting in complete crystallization of amorphous phase with formation of pure monoclinic HfO 2 . It was found that the rate of m-HfO 2 formation can be significantly increased by combining hydrothermal treatment with simultaneous ultrasonic activation

  8. Formation of discrete solitons as a function of waveguide array geometry under the well-confined mode condition

    International Nuclear Information System (INIS)

    Vergara-Betancourt, A; Martí-Panameño, E; Luis-Ramos, A; Parada-Alfonso, R

    2013-01-01

    Based on numerical techniques, in this paper, we study light propagation in two types of waveguide arrays. One array contains hexagonal cells, and the second contains honeycomb cells. The waveguides demonstrate the well-confined mode condition and possess Kerr nonlinearity. The mathematical model is based on the modified discrete nonlinear Schrödinger equation, which allows us to evaluate the influence of the array geometry on nonlinear light propagation, primarily the process of discrete soliton formation. The main conclusion involves the role of the coupling length; the greater the coupling length, the lower the power threshold required for discrete soliton formation. (paper)

  9. The klein paradox as a many particle problem

    Energy Technology Data Exchange (ETDEWEB)

    Bongaarts, P.J.M.; Ruijsenaars, S.N.M.

    1976-09-24

    A mathematically rigorous analysis of the Klein paradox is given in the many-particle formulation of the Dirac theory. This paradox was meant as an example demonstrating the negative energy problems of the single particle Dirac equation. However, it is shown that this problem does not disappear in the second quantized version of the Dirac theory. It corresponds with a situation which cannot be described properly within the framework of a field theory with an external potential. (AIP)

  10. Use of paradox in the treatment of alcoholism.

    Science.gov (United States)

    Shore, J J

    1981-02-01

    Using a paradoxical approach in dealing with an alcoholic's denial of alcoholism and resistance to treatment allows the therapist to maintain an empathic stance while placing the responsibility for change on the alcoholic. The author discusses the theory of paradox, its use by Alcoholics Anonymous and Al-Anon, the power dynamics of the therapeutic process, and the specific strategies and ethics of this approach to therapy.

  11. Estimation of maximum burial depth of Neogene-Quaternary fore-arc basin formation based on laboratory porosity measurements under pressure

    Science.gov (United States)

    Uehara, Shin-ichi; Tamura, Yukie; Marumo, Haruna; Mitsuhashi, Shunsuke

    2016-05-01

    Estimating the maximum effective stress that rocks have experienced, Pe,max, or the maximum burial depth for sedimentary rocks, Dmax, is important for many types of research, ranging from engineering applications to estimation of tectonic evolution. We estimated Pe,max and Dmax for the Kazusa fore-arc basin formations (the Kazusa Group) in the Boso Peninsula of Japan using a laboratory-based method. We carried out measurements of porosity n with siltstone specimens from the Kazusa Group formations (the Umegase, Otadai, Kiwada, Ohara, and Katsuura formations) under various effective pressure Pe conditions and estimated Pe,max from the inflection points of the log Pe-log n curve on the Pe increasing path. Except for the specimens from the Ohara Formation, estimated values of Pe,max ranged from approximately 13-24 MPa. This range corresponded to approximately 1.3-3.2 km of Dmax. Differences in Dmax among the specimens were at least four times smaller than distances normal to bedding planes among the sampling locations. This suggests that the formations were not deposited horizontally, but that deposition proceeded as the subsidence center of the fore-arc basin moved in a northwestward (NW) direction, and that formations were then uplifted almost horizontally. The Pe,max of the specimens from the Ohara Formation were 6-10 MPa smaller than the others. Thus, it is possible that pore pressure at the sampling location was more than 6 MPa larger than the hydrostatic condition when the sediments were deposited and lithified. Previous studies reported the center of a high-porosity zone at the Ohara Formation, and this high-porosity zone probably developed due to Pp over-pressurization. These results support the applicability of this method to estimation of tectonic evolution of sedimentary basins and magnitude of over-pressurization.

  12. A control engineering approach to understanding the TGF-β paradox in cancer.

    Science.gov (United States)

    Chung, Seung-Wook; Cooper, Carlton R; Farach-Carson, Mary C; Ogunnaike, Babatunde A

    2012-06-07

    TGF-β, a key cytokine that regulates diverse cellular processes, including proliferation and apoptosis, appears to function paradoxically as a tumour suppressor in normal cells, and as a tumour promoter in cancer cells, but the mechanisms underlying such contradictory roles remain unknown. In particular, given that this cytokine is primarily a tumour suppressor, the conundrum of the unusually high level of TGF-β observed in the primary cancer tissue and blood samples of cancer patients with the worst prognosis, remains unresolved. To provide a quantitative explanation of these paradoxical observations, we present, from a control theory perspective, a mechanistic model of TGF-β-driven regulation of cell homeostasis. Analysis of the overall system model yields quantitative insight into how cell population is regulated, enabling us to propose a plausible explanation for the paradox: with the tumour suppressor role of TGF-β unchanged from normal to cancer cells, we demonstrate that the observed increased level of TGF-β is an effect of cancer cell phenotypic progression (specifically, acquired TGF-β resistance), not the cause. We are thus able to explain precisely why the clinically observed correlation between elevated TGF-β levels and poor prognosis is in fact consistent with TGF-β's original (and unchanged) role as a tumour suppressor.

  13. Parrondo's games based on complex networks and the paradoxical effect.

    Directory of Open Access Journals (Sweden)

    Ye Ye

    Full Text Available 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.

  14. Parrondo's games based on complex networks and the paradoxical effect.

    Science.gov (United States)

    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.

  15. SO3 Formation and the Effect of Fly Ash in a Bubbling Fluidised Bed under Oxy-Fuel Combustion Conditions.

    Czech Academy of Sciences Publication Activity Database

    Sarbassov, Y.; Duan, L.; Jeremiáš, Michal; Manovic, V.; Anthony, E.J.

    2017-01-01

    Roč. 167, DEC 1 (2017), s. 314-321 ISSN 0378-3820 Institutional support: RVO:67985858 Keywords : SO3 formation * oxy-fuel combustion * fluidised bed Subject RIV: JE - Non-nuclear Energetics, Energy Consumption ; Use OBOR OECD: Energy and fuels Impact factor: 3.752, year: 2016

  16. Molecular Mechanisms Underlying Formation of Long-Term Reward Memories and Extinction Memories in the Honeybee ("Apis Mellifera")

    Science.gov (United States)

    Eisenhardt, Dorothea

    2014-01-01

    The honeybee ("Apis mellifera") has long served as an invertebrate model organism for reward learning and memory research. Its capacity for learning and memory formation is rooted in the ecological need to efficiently collect nectar and pollen during summer to ensure survival of the hive during winter. Foraging bees learn to associate a…

  17. Root iron plaque formation and characteristics under N2 flushing and its effects on translocation of Zn and Cd in paddy rice seedlings (Oryza sativa).

    Science.gov (United States)

    Xu, Bo; Yu, Shen

    2013-06-01

    Anoxic conditions are seldom considered in root iron plaque induction of wetland plants in hydroponic experiments, but such conditions are essential for root iron plaque formation in the field. Although ferrous ion availability and root radial oxygen loss capacity are generally taken into account, neglect of anoxic conditions in root iron plaque formation might lead to an under- or over-estimate of their functional effects, such as blocking toxic metal uptake. This study hypothesized that anoxic conditions would influence root iron plaque formation characteristics and translocation of Zn and Cd by rice seedlings. A hydroponic culture was used to grow rice seedlings and a non-disruptive approach for blocking air exchange between the atmosphere and the induction solution matrix was applied for root iron plaque formation, namely flushing the headspace of the induction solution with N2 during root iron plaque induction. Zn and Cd were spiked into the solution after root iron plaque formation, and translocation of both metals was determined. Blocking air exchange between the atmosphere and the nutrient solution by N2 flushing increased root plaque Fe content by between 11 and 77 % (average 31 %). The N2 flushing treatment generated root iron plaques with a smoother surface than the non-N2 flushing treatment, as observed by scanning electron microscopy, but Fe oxyhydroxides coating the rice seedling roots were amorphous. The root iron plaques sequestrated Zn and Cd and the N2 flushing enhanced this effect by approx. 17 % for Zn and 71 % for Cd, calculated by both single and combined additions of Zn and Cd. Blocking of oxygen intrusion into the nutrient solution via N2 flushing enhanced root iron plaque formation and increased Cd and Zn sequestration in the iron plaques of rice seedlings. This study suggests that hydroponic studies that do not consider redox potential in the induction matrices might lead to an under-estimate of metal sequestration by root iron plaques of

  18. A FIB/TEM study of butterfly crack formation and white etching area (WEA) microstructural changes under rolling contact fatigue in 100Cr6 bearing steel

    Energy Technology Data Exchange (ETDEWEB)

    Evans, M.-H., E-mail: martin.evans@soton.ac.uk [National Centre for Advanced Tribology at Southampton (nCATS), University of Southampton, SO17 1BJ (United Kingdom); Walker, J.C.; Ma, C.; Wang, L.; Wood, R.J.K. [National Centre for Advanced Tribology at Southampton (nCATS), University of Southampton, SO17 1BJ (United Kingdom)

    2013-05-15

    Butterflies are microscopic damage features forming at subsurface material imperfections induced during rolling contact fatigue (RCF) in rolling element bearings. Butterflies can lead to degradation of the load bearing capacity of the material by their associated cracks causing premature spalling failures. Recently, butterfly formation has been cited to be related to a premature failure mode in wind turbine gearbox bearings; white structure flaking (WSF). Butterflies consist of cracks with surrounding microstructural change called ‘white etching area’ (WEA) forming wings that revolve around their initiators. The formation mechanisms of butterflies in bearing steels have been studied over the last 50 years, but are still not fully understood. This paper presents a detailed microstructural analysis of a butterfly that has initiated from a void in standard 100Cr6 bearing steel under rolling contact fatigue on a laboratory two-roller test rig under transient operating conditions. Analysis was conducted using focused ion beam (FIB) tomography, 3D reconstruction and transmission electron microscopy (STEM/TEM) methods. FIB tomography revealed an extensive presence of voids/cavities immediately adjacent to the main crack on the non-WEA side and at the crack tip. This provides evidence for a void/cavity coalescence mechanism for the butterfly cracks formation. Spherical M{sub 3}C carbide deformation and dissolution as part of the microstructural change in WEA were observed in both FIB and STEM/TEM analyses, where TEM analyses also revealed the formation of superfine nano-grains (3–15 nm diameter) intersecting a dissolving spherical M{sub 3}C carbide. This is evidence of the early formation of nano-grains associated with the WEA formation mechanism.

  19. Racial science, geopolitics, and empires: paradoxes of power.

    Science.gov (United States)

    Tilley, Helen

    2014-12-01

    Scholars interested in the history of racial science continue to puzzle over the ways in which such ideas endure. This essay takes up a variant on this theme by considering how critiques of ideas about racial purity and hierarchies, expressed at the Universal Races Congress of 1911, were part of a larger intellectual project that simultaneously under- mined ideas of fixed racial types and bolstered identity categories defined in racial terms. Efforts to destabilize racial science in the early decades of the twentieth century often went hand in glove with burgeoning critiques of "white" and European domination in different parts of the world. This essay shines the spotlight on the paradoxical nature of these processes. While anthropologists helped to spearhead attempts to deconstruct mainstream pillars of racial science, they also left the door open for its reconstitution by refusing to reject classificatory schemes by group. And though global conversations about race and science tended to generate more cosmopolitan and egalitarian views, the very act of bringing together people from different places had the unintended effect of reinforcing racial identities and idioms, especially in the context of challenges to colonial rule. Finally, even as state building within empires ensured that racial taxonomies proliferated on the ground, imperial bureaucrats often avoided promoting racial science and research because such endeavors were a divisive force in transnational management.

  20. Reasonable Plurality and Moral Education. New Perspectives on Old Paradoxes.

    Directory of Open Access Journals (Sweden)

    Ana María Salmerón Castro

    2000-05-01

    Full Text Available This article faces an old paradox of moral education: the apparently logical impossibility of choosing the transmission of agreed-upon values and the autonomous exercise of reason. The author takes an epistemological position in which human learning is considered the result of an interaction of individual developmental processes and the acquisition of knowledge. She assumes knowledge as a category subjected to criteria of truth, and this, as preceded by an agreement concerning values. She states that transmission of the community consensus is not only inevitable, but is essential to the development of the autonomous deliberative game and to the exercise of critical intelligence as well. However, she warns us against a possible danger: the mere transmission of accepted principles and values may place moral education under a heterogeneous direction of conduct. Educators should, by all means, avoid such a risk. She suggests seeking a reasonable plurality as a means of transmitting agreed-upon values. The notion of reasonable plurality derives from a feature assigned to John Rawls’ concept of “overlapping consensus”.

  1. Neutralising the meat paradox: Cognitive dissonance, gender, and eating animals.

    Science.gov (United States)

    Dowsett, Elisha; Semmler, Carolyn; Bray, Heather; Ankeny, Rachel A; Chur-Hansen, Anna

    2018-04-01

    Meat eating is a common behaviour, despite many people claiming to like, love, and care about animals. The apparent disconnection between not wanting animals to suffer, yet killing them for food, has been termed the 'meat paradox.' In this experimental study (N = 460), participants completed pre-affect, post-affect, meat attachment, and attitude towards animals questionnaires, under two conditions: exposure to the life of an Australian meat lamb, and information about the nutritional benefits of meat. A factorial MANOVA revealed that negative affect was significantly greater when participants were exposed to the meat-animal connection; however, more entrenched attitudes towards animals and attachment to meat remained unaffected. Significant gender effects were found across all variables: most notably, meat attachment differed according to gender, decreasing in women and increasing in men when exposed to the meat-animal condition. Open-ended responses were subjected to content analysis to understand participants' future meat-consumption preferences and accompanying reasoning strategies. Findings from the present study contribute to understanding how cognitive dissonance and inconsistencies are rationalised by meat consumers. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. The paradox of the neutrophil's role in tissue injury.

    Science.gov (United States)

    Segel, George B; Halterman, Marc W; Lichtman, Marshall A

    2011-03-01

    The neutrophil is an essential component of the innate immune system, and its function is vital to human life. Its production increases in response to virtually all forms of inflammation, and subsequently, it can accumulate in blood and tissue to varying degrees. Although its participation in the inflammatory response is often salutary by nature of its normal interaction with vascular endothelium and its capability to enter tissues and respond to chemotactic gradients and to phagocytize and kill microrganisms, it can contribute to processes that impair vascular integrity and blood flow. The mechanisms that the neutrophil uses to kill microorganisms also have the potential to injure normal tissue under special circumstances. Its paradoxical role in the pathophysiology of disease is particularly, but not exclusively, notable in seven circumstances: 1) diabetic retinopathy, 2) sickle cell disease, 3) TRALI, 4) ARDS, 5) renal microvasculopathy, 6) stroke, and 7) acute coronary artery syndrome. The activated neutrophil's capability to become adhesive to endothelium, to generate highly ROS, and to secrete proteases gives it the potential to induce local vascular and tissue injury. In this review, we summarize the evidence for its role as a mediator of tissue injury in these seven conditions, making it or its products potential therapeutic targets.

  3. The Paradox of Leisure in Later Life

    Science.gov (United States)

    Nimrod, Galit; Shrira, Amit

    2016-01-01

    Objective. Numerous studies have shown that involvement in leisure activity has a significant impact on older adults’ physical, psychological, social, and spiritual well-being. This study explores whether the association between leisure involvement and well-being in later life changes over time. Method. Data were drawn from the first 4 waves of the Survey of Health, Ageing, and Retirement in Europe (SHARE). Growth curve models were applied to examine whether leisure moderated change in quality of life (QoL) over time among 7,875 retirees aged 60 and older. Results. Findings indicated that the association between leisure and QoL increased with time, as nonactive respondents displayed a decline in QoL over time, whereas those with high levels of leisure involvement showed an increase. Findings remained significant after controlling for sociodemographics, health, and cognitive functioning. Discussion. Results indicated that the significance of leisure to well-being increases throughout the later life course, and that leisure may act as a resource for resilience in old age. They also pointed out a paradoxical situation in which the older seniors, who may benefit from leisure involvement more than their younger peers, are precisely the ones who face the greater number of constraints to beneficial use of leisure. PMID:25315158

  4. Orígenes: um pensador paradoxal?

    Directory of Open Access Journals (Sweden)

    Rogério Miranda de Almeida

    2016-01-01

    Full Text Available Estas reflexões têm como objetivo principal mostrar o caráter essencialmente paradoxal do pensamento de Orígenes. Na verdade, este paradoxo se desdobra no pensador alexandrino sob uma dupla modalidade: no seu pensamento e na experiência mesma da sua escrita, que é inseparável daquele. Consideramos, com efeito, que a escrita, enquanto espaço de resistências pelas quais se desenrola o desejo, não somente manifesta o pensamento de um autor, mas também determina este pensamento e, ao mesmo tempo, é por ele determinada. Na realidade, esta questão poderia ser aplicada não somente a Orígenes, mas também a todo pensador, ou melhor, a todo escritor. Em Orígenes, porém, esta problemática assume uma importância particular, na medida em que, sendo ele um exegeta e um escritor, ele se empenha em analisar e entender a relação entre fé e razão, ou “sabedoria cristã” e “sabedoria pagã”.

  5. First evidence for "The backup plan paradox".

    Science.gov (United States)

    Napolitano, Christopher M; Freund, Alexandra M

    2017-08-01

    This research is a first test of the backup plan paradox. We hypothesized that investing in a backup plan may facilitate the conditions that it was developed to address: Plan A's insufficiency. Five studies provide initial, primarily correlative support for the undermining effect of investing in a backup plan. Study 1 (n= 160) demonstrated that the more participants perceived they had invested in developing a backup plan (preparing a "crib sheet"), the more likely they were to use it, although greater investments were unrelated to backup plan utility. Studies 2-4 used a simulated negotiation task. Study 2 (n = 247) demonstrated that when goal-relevant resources are limited, investing in developing backup plans and perceiving them as highly instrumental can decrease goal performance through the indirect effect of increased means replacing. Study 3 (n = 248) replicated this effect when goal-relevant resources were plentiful. Study 4 (n = 204) used an experimental variant of the simulated negotiation task and demonstrated that simply having a backup plan is not detrimental, but perceiving backup plans to be highly instrumental decreased goal performance, again through the indirect effect of increased means replacing. Study 5 (n = 160) replicated findings from Studies 1-4 using a lab-based motor task (throwing a ball). Together, these results provide first evidence that backup plans can introduce costs that may jeopardize goal performance. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  6. Paradoxical reaction in immunocompetent children with tuberculosis.

    Science.gov (United States)

    Carazo Gallego, Begoña; Moreno-Pérez, David; Nuñez Cuadros, Esmeralda; Mesa Fernandez, Alba; Martin Cantero, María; Obando Pacheco, Pablo; Urda Cardona, Antonio

    2016-10-01

    A paradoxical reaction (PR) during anti-tuberculosis treatment is a phenomenon that is poorly studied in immunocompetent children. It is defined as a clinical or radiological worsening of pre-existing tuberculosis (TB) disease. A retrospective descriptive study of children younger than 14 years of age was performed; these children developed PR during the years 2009 to 2014, following a diagnosis of TB. Demographic characteristics, microbiological results, treatment and outcome data were collected. Of 51 children diagnosed with TB, five (9.8%) developed a PR; four of these children had pulmonary TB and the remaining patient had miliary TB with central nervous system involvement. The PR occurred at a median of 42 days (range 23-53 days) after initiating therapy. Corticosteroids were started when PR was suspected, at a median dose of 1mg/kg/day. Clinical and radiological improvement was noted in all cases, with a median clinical regression time of 10.5 days (range 3-15 days) and a median radiological regression time of 45 days (range 26-105 days). No sequelae were described in any patient. PR in immunocompetent children during anti-tuberculosis treatment is not such an unusual reaction. Treatment with corticosteroids may be useful for the resolution of PR. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. Marketing human organs: the autonomy paradox.

    Science.gov (United States)

    Marshall, P A; Thomasma, D C; Daar, A S

    1996-03-01

    The severe shortage of organs for transplantation and the continual reluctance of the public to voluntarily donate has prompted consideration of alternative strategies for organ procurement. This paper explores the development of market approaches for procuring human organs for transplantation and considers the social and moral implications of organ donation as both a "gift of life" and a "commodity exchange." The problematic and paradoxical articulation of individual autonomy in relation to property rights and marketing human body parts is addressed. We argue that beliefs about proprietorship over human body parts and the capacity to provide consent for organ donation are culturally constructed. We contend that the political and economic framework of biomedicine, in western and non-western nations, influences access to transplantation technology and shapes the form and development of specific market approaches. Finally, we suggest that marketing approaches for organ procurement are and will be negotiated within cultural parameters constrained by several factors: beliefs about the physical body and personhood, religious traditions, economic conditions, and the availability of technological resources.

  8. Formation of environmentally persistent free radicals as the mechanism for reduced catechol degradation on hematite-silica surface under UV irradiation.

    Science.gov (United States)

    Li, Hao; Pan, Bo; Liao, Shaohua; Zhang, Di; Xing, Baoshan

    2014-05-01

    Iron is rich in soils, and is recently reported to form stable complexes with organic free radicals, generating environmentally persistent free radicals (EPFRs). The observation may challenge the common viewpoint that iron is an effective catalyst to facilitate the degradation of various organic chemicals. But no study was specifically designed to investigate the possible inhibited degradation of organic chemicals because of the formation of EPFRs in dry environment. We observed that catechol degradation under UV irradiation was decreased over 20% in silica particles coated with 1% hematite in comparison to uncoated silica particles. Stabilized semiquinone or quinine and phenol radicals were involved in HMT-silica system. EPFR formation was thus the reason for the reduced catechol degradation on HMT-silica surface under UV irradiation at ambient temperature. EPFRs should be incorporated in the studies of organic contaminants geochemical behavior, and will be a new input in their environmental fate modeling. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. S-Nitrosomycothiol Reductase and Mycothiol Are Required for Survival Under Aldehyde Stress and Biofilm Formation in Mycobacterium smegmatis

    Science.gov (United States)

    Vargas, Derek; Hageman, Samantha; Gulati, Megha; Nobile, Clarissa J.; Rawat, Mamta

    2017-01-01

    We show that Mycobacterium smegmatis mutants disrupted in mscR, coding for a dual function S-nitrosomycothiol reductase and formaldehyde dehydrogenase, and mshC, coding for a mycothiol ligase and lacking mycothiol (MSH), are more susceptible to S-nitrosoglutathione (GSNO) and aldehydes than wild type. MSH is a cofactor for MscR, and both mshC and mscR are induced by GSNO and aldehydes. We also show that a mutant disrupted in egtA, coding for a γ-glutamyl cysteine synthetase and lacking in ergothioneine, is sensitive to nitrosative stress but not to aldehydes. In addition, we find that MSH and S-nitrosomycothiol reductase are required for normal biofilm formation in M. smegmatis, suggesting potential new therapeutic pathways to target to inhibit or disrupt biofilm formation. PMID:27321674

  10. Prevention of melanin formation during aryl alcohol oxidase production under growth-limited conditions using an Aspergillus nidulans cell factory.

    Science.gov (United States)

    Pardo-Planas, Oscar; Prade, Rolf A; Müller, Michael; Atiyeh, Hasan K; Wilkins, Mark R

    2017-11-01

    An Aspergillus nidulans cell factory was genetically engineered to produce an aryl alcohol oxidase (AAO). The cell factory initiated production of melanin when growth-limited conditions were established using stationary plates and shaken flasks. This phenomenon was more pronounced when the strain was cultured in a trickle bed reactor (TBR). This study investigated different approaches to reduce melanin formation in fungal mycelia and liquid medium in order to increase the enzyme production yield. Removal of copper from the medium recipe reduced melanin formation in agar cultures and increased enzyme activities by 48% in agitated liquid cultures. Copper has been reported as a key element for tyrosinase, an enzyme responsible for melanin production. Ascorbic acid (0.44g/L) stopped melanin accumulation, did not affect growth parameters and resulted in AAO activity that was more than two-fold greater than a control treatment with no ascorbic acid. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Thrombin generation and fibrin clot formation under hypothermic conditions: an in vitro evaluation of tissue factor initiated whole blood coagulation.

    Science.gov (United States)

    Whelihan, Matthew F; Kiankhooy, Armin; Brummel-Ziedins, Kathleen E

    2014-02-01

    Despite trauma-induced hypothermic coagulopathy being familiar in the clinical setting, empirical experimentation concerning this phenomenon is lacking. In this study, we investigated the effects of hypothermia on thrombin generation, clot formation, and global hemostatic functions in an in vitro environment using a whole blood model and thromboelastography, which can recapitulate hypothermia. Blood was collected from healthy individuals through venipuncture and treated with corn trypsin inhibitor, to block the contact pathway. Coagulation was initiated with 5pM tissue factor at temperatures 37°C, 32°C, and 27°C. Reactions were quenched over time, with soluble and insoluble components analyzed for thrombin generation, fibrinogen consumption, factor (f)XIII activation, and fibrin deposition. Global coagulation potential was evaluated through thromboelastography. Data showed that thrombin generation in samples at 37°C and 32°C had comparable rates, whereas 27°C had a much lower rate (39.2 ± 1.1 and 43 ± 2.4 nM/min vs 28.6 ± 4.4 nM/min, respectively). Fibrinogen consumption and fXIII activation were highest at 37°C, followed by 32°C and 27°C. Fibrin formation as seen through clot weights also followed this trend. Thromboelastography data showed that clot formation was fastest in samples at 37°C and lowest at 27°C. Maximum clot strength was similar for each temperature. Also, percent lysis of clots was highest at 37°C followed by 32°C and then 27°C. Induced hypothermic conditions directly affect the rate of thrombin generation and clot formation, whereas global clot stability remains intact. © 2013.

  12. Electrochemical studies of the film formation on lithium in propylene carbonate solutions under open-circuit conditions

    Energy Technology Data Exchange (ETDEWEB)

    Geronov, Y.; Schwager, F.; Muller, R.H.

    1981-11-01

    The nature of protective surface layers formed on lithium in propylene carbonate solutions of LiClO/sub 4/ and LiAsF/sub 6/ at open circuit has been investigated by electrochemical pulse measurements. The results are consistent with the fast formation of a compact thin layer resulting from the reaction with residual water. This layer acts as a solid ionic conductor. Slow corrosion or decomposition processes produce a thicker porous overlayer.

  13. Precambrian-Cambrian boundary in the Tal formation of Garhwal Lesser Himalaya : Rb-Sr age evidence from black shales underlying phosphorites

    International Nuclear Information System (INIS)

    Sharma, K.K.; Rameshwar Rao, D.; Azmi, R.J.; Gopalan, K.; Pantulu, G.V.C.

    1991-01-01

    The recently reported faunal evidence for placing the Precambrian-Cambrian boundary within the main phosphorite unit of the Chert-Phosphorite Member of the Tal Formation, Garhwal Lesser Himalaya, is supported by the present report of 626 ± 13 myr for the whole-rock Rb-Sr isochron age of the black shales directly underlying the phosphorite band. (author). 15 refs., 2 figs., 1 tab

  14. SIRT6 reduces macrophage foam cell formation by inducing autophagy and cholesterol efflux under ox-LDL condition.

    Science.gov (United States)

    He, Jiangping; Zhang, Guangya; Pang, Qi; Yu, Cong; Xiong, Jie; Zhu, Jing; Chen, Fengling

    2017-05-01

    SIRT6 is a pivotal regulator of lipid metabolism. It is also closely connected to cardiovascular diseases, which are the main cause of death in diabetic patients. We observed a decrease in the expression of SIRT6 and key autophagy effectors (ATG5, LC3B, and LAMP1) in ox-LDL-induced foam cells, a special form of lipid-laden macrophages. In these cells, SIRT6 WT but not SIRT6 H133Y overexpression markedly reduced foam cell formation, as shown by Oil Red O staining, while inducing autophagy flux, as determined by both mRFP-GFP-LC3 labeling and transmission electron microscopy. Silencing the key autophagy initiation gene ATG5, reversed the autophagy-promoting effect of SIRT6 in ox-LDL-treated THP1 cells, as evidenced by an increase in foam cells. Cholesterol efflux assays indicated that SIRT6 overexpression in foam cells promoted cholesterol efflux, increased the levels of ABCA1 and ABCG1, and reduced miR-33 levels. By transfecting miR-33 into cells overexpressing SIRT6, we observed that reduced foam cell formation and autophagy flux induction were largely reversed. These data imply that SIRT6 plays an essential role in protecting against atherosclerosis by reducing foam cell formation through an autophagy-dependent pathway. © 2017 Federation of European Biochemical Societies.

  15. Investigating the molecular underpinnings underlying morphology and changes in carbon partitioning during tension wood formation in Eucalyptus.

    Science.gov (United States)

    Mizrachi, Eshchar; Maloney, Victoria J; Silberbauer, Janine; Hefer, Charles A; Berger, Dave K; Mansfield, Shawn D; Myburg, Alexander A

    2015-06-01

    Tension wood has distinct physical and chemical properties, including altered fibre properties, cell wall composition and ultrastructure. It serves as a good system for investigating the genetic regulation of secondary cell wall biosynthesis and wood formation. The reference genome sequence for Eucalyptus grandis allows investigation of the global transcriptional reprogramming that accompanies tension wood formation in this global wood fibre crop. We report the first comprehensive analysis of physicochemical wood property changes in tension wood of Eucalyptus measured in a hybrid (E. grandis × Eucalyptus urophylla) clone, as well as genome-wide gene expression changes in xylem tissues 3 wk post-induction using RNA sequencing. We found that Eucalyptus tension wood in field-grown trees is characterized by an increase in cellulose, a reduction in lignin, xylose and mannose, and a marked increase in galactose. Gene expression profiling in tension wood-forming tissue showed corresponding down-regulation of monolignol biosynthetic genes, and differential expression of several carbohydrate active enzymes. We conclude that alterations of cell wall traits induced by tension wood formation in Eucalyptus are a consequence of a combination of down-regulation of lignin biosynthesis and hemicellulose remodelling, rather than the often proposed up-regulation of the cellulose biosynthetic pathway. © 2014 University of Pretoria New Phytologist © 2014 New Phytologist Trust.

  16. Heterogeneous Shallow-Shelf Carbonate Buildups in the Paradox Basin, Utah and Colorado: Targets for Increased Oil Production and Reserves Using Horizontal Drilling Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Chidsey, Thomas C. Jr.; Eby, David E.; Wray, Laura L.

    2001-04-19

    The primary objective of this project was to enhance domestic petroleum production by demonstration and transfer of horizontal drilling technology in the Paradox basin, Utah, Colorado, Arizona, and New Mexico. If this project can demonstrate technical and economic feasibility, then the technique can be applied to approximately 100 additional small fields in the Paradox basin alone, and result in increased recovery of 25 to 50 million barrels (40-80 million m3) of oil. This project was designed to characterize several shallow-shelf carbonate reservoirs in the Pennsylvania (Desmoinesian) Paradox Formation, choose the best candidate(s) for a pilot demonstration project to drill horizontally from existing vertical wells, monitor well performances, and report associated validation activities.

  17. Genetic Susceptibility and Predictors of Paradoxical Reactions in Buruli Ulcer.

    Directory of Open Access Journals (Sweden)

    Yves Thierry Barogui

    2016-04-01

    Full Text Available Buruli ulcer (BU is the third most frequent mycobacterial disease in immunocompetent persons after tuberculosis and leprosy. During the last decade, eight weeks of antimicrobial treatment has become the standard of care. This treatment may be accompanied by transient clinical deterioration, known as paradoxical reaction. We investigate the incidence and the risks factors associated with paradoxical reaction in BU.The lesion size of participants was assessed by careful palpation and recorded by serial acetate sheet tracings. For every time point, surface area was compared with the previous assessment. All patients received antimicrobial treatment for 8 weeks. Serum concentration of 25-hydroxyvitamin D, the primary indicator of vitamin D status, was determined in duplex for blood samples at baseline by a radioimmunoassay. We genotyped four polymorphisms in the SLC11A1 gene, previously associated with susceptibility to BU. For testing the association of genetic variants with paradoxical responses, we used a binary logistic regression analysis with the occurrence of a paradoxical response as the dependent variable.Paradoxical reaction occurred in 22% of the patients; the reaction was significantly associated with trunk localization (p = .039 by Χ(2, larger lesions (p = .021 by Χ(2 and genetic factors. The polymorphisms 3'UTR TGTG ins/ins (OR 7.19, p < .001 had a higher risk for developing paradoxical reaction compared to ins/del or del/del polymorphisms.Paradoxical reactions are common in BU. They are associated with trunk localization, larger lesions and polymorphisms in the SLC11A1 gene.

  18. Gold nanoshell photomodification under a single-nanosecond laser pulse accompanied by color-shifting and bubble formation phenomena

    International Nuclear Information System (INIS)

    Akchurin, Garif; Khlebtsov, Boris; Akchurin, Georgy; Tuchin, Valery; Zharov, Vladimir; Khlebtsov, Nikolai

    2008-01-01

    Laser-nanoparticle interaction is crucial for biomedical applications of lasers and nanotechnology to the treatment of cancer or pathogenic microorganisms. We report on the first observation of laser-induced coloring of gold nanoshell solution after a one nanosecond pulse and an unprecedentedly low bubble formation (as the main mechanism of cancer cell killing) threshold at a laser fluence of about 4 mJ cm -2 , which is safe for normal tissue. Specifically, silica/gold nanoshell (140/15 nm) suspensions were irradiated with a single 4 ns (1064 nm) or 8 ns (900 nm) laser pulse at fluences ranging from 0.1 mJ cm -2 to 50 J cm -2 . Solution red coloring was observed by the naked eye confirmed by blue-shifting of the absorption spectrum maximum from the initial 900 nm for nanoshells to 530 nm for conventional colloidal gold nanospheres. TEM images revealed significant photomodification of nanoparticles including complete fragmentation of gold shells, changes in silica core structure, formation of small 20-30 nm isolated spherical gold nanoparticles, gold nanoshells with central holes, and large and small spherical gold particles attached to a silica core. The time-resolved monitoring of bubble formation phenomena with the photothermal (PT) thermolens technique demonstrated that after application of a single 8 ns pulse at fluences 5-10 mJ cm -2 and higher the next pulse did not produce any PT response, indicating a dramatic decrease in absorption because of gold shell modification. We also observed a dependence of the bubble expansion time on the laser energy with unusually very fast PT signal rising (∼3.5 ns scale at 0.2 J cm -2 ). Application of the observed phenomena to medical applications is discussed, including a simple visual color test for laser-nanoparticle interaction

  19. THE FORMATION OF READINESS FOR PERSONAL SELF-DETERMINATION WITH DEVIANT TEENAGERS UNDER THE CONDITIONS OF AN EDUCATIONAL INSTITUTION

    Directory of Open Access Journals (Sweden)

    Kopovaya Oksana Vladimirovna

    2013-02-01

    Full Text Available The paper presents the results of introduction of a practice-oriented model of a pedagogical system into the educational process of a school and a vocational school. The system stimulates the process of the formation of readiness for personal self-determination of a modern teenager as an integration of external influences on a forming personality and his or her active internal self-development. The result of the research can be used in the work of psychologists, pedagogue-psychologists, social pedagogues in institutions of general, primary professional and specialized secondary education.

  20. Embolia paradojal inminente Impending paradoxical embolism

    Directory of Open Access Journals (Sweden)

    Miguel A. Veltri

    2006-12-01

    Full Text Available La presencia de un trombo venoso atrapado en un defecto interauricular e insinuándose en las cavidades izquierdas configura una forma extremadamente inusual de enfermedad tromboembólica denominada embolia paradojal inminente. Presentamos el caso de un varón de 71 años, sometido 10 días antes a adenomectomía prostática, que consultó por disnea y mareos. Se le diagnosticó tromboembolismo pulmonar bilateral por tomografía axial computada helicoidal. Se lo anticoaguló con heparina sódica y se le realizó un ecocardiograma transesofágico que mostró un trombo que atravesaba el foramen oval y se alojaba en la aurícula izquierda. No presentaba signos clínicos de embolización sistémica. Se realizó la embolectomía quirúrgica y cierre del defecto auricular. El paciente falleció.An intracardiac thrombus traversing a patent foramen ovale is a very infrequent but potentially catastrophic complication of the thromboembolic disease. It is named "impending paradoxical embolism". We report the case of a 71 year old Caucasian male warded in ten days after a prostatectomy because of bilateral pulmonary embolism. Diagnosis was confirmed by HCT scan and the patient received anticoagulation with heparin. A transesophageal ecocardiogram disclosed a thrombus traversing foramen ovale into the left atrium. Surgical embolectomy was performed, but the patient died shortly after surgery.

  1. Formation of a supersaturated carbon solution in a metal under the process of carbon nano fibers obtaining by PECVD

    International Nuclear Information System (INIS)

    Takopulo, D. A.; Fisenko, S. P.

    2012-01-01

    Heat and mass transfer processes in a highly porous carbon layer appeared on a catalytic surface of a plasma chemical reactor during carbon nano fibers obtaining by PECVD (plasma enhanced CVD) are considered. Nano fibers formation in such a process is carried out as a result of the catalytic decomposition of the carbon contained plasma pyrolysis yields followed by carbon atoms diffusion into the catalyst bulk with a subsequent formation of carbon in a metal solid solution. The results of the numerical investigation of the transfer processes in the porous layer have shown that the layer thickness growth significantly reduces the catalytic surface temperature. This effect causes the carbon solid solution supersaturation, which is an obligatory condition of the carbon clusters nucleation. The transfer problems initial data have been obtained in a result of experimental investigations of thin porous carbon layers gathered from the catalytic surface of the plasma chemical reactor. It have been determined that the layer porosity has an average value of about 70%, and it's effective heat conductivity in the temperature range of 600-1000 C is about 10 -1 W/(m*K) and slightly depends on the temperature. A numerical modeling has been made for a steady state approximation. The correctness of this approximation is based on the comparison of the steady stale stabilization characteristic time with the porous layer growth characteristic time. The latter appeared to be much longer than the former one. (authors).

  2. Leaf surface wax is a source of plant methane formation under UV radiation and in the presence of oxygen.

    Science.gov (United States)

    Bruhn, D; Mikkelsen, T N; Rolsted, M M M; Egsgaard, H; Ambus, P

    2014-03-01

    The terrestrial vegetation is a source of UV radiation-induced aerobic methane (CH4 ) release to the atmosphere. Hitherto pectin, a plant structural component, has been considered as the most likely precursor for this CH4 release. However, most of the leaf pectin is situated below the surface wax layer, and UV transmittance of the cuticle differs among plant species. In some species, the cuticle effectively absorbs and/or reflects UV radiation. Thus, pectin may not necessarily contribute substantially to the UV radiation-induced CH4 emission measured at surface level in all species. Here, we investigated the potential of the leaf surface wax itself as a source of UV radiation-induced leaf aerobic CH4 formation. Isolated leaf surface wax emitted CH4 at substantial rates in response to UV radiation. This discovery has implications for how the phenomenon should be scaled to global levels. In relation to this, we demonstrated that the UV radiation-induced CH4 emission is independent of leaf area index above unity. Further, we observed that the presence of O2 in the atmosphere was necessary for achieving the highest rates of CH4 emission. Methane formation from leaf surface wax is supposedly a two-step process initiated by a photolytic rearrangement reaction of the major component followed by an α-cleavage of the generated ketone. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

  3. Enzyme mediated silicon-oxygen bond formation; the use of Rhizopus oryzae lipase, lysozyme and phytase under mild conditions.

    Science.gov (United States)

    Abbate, Vincenzo; Bassindale, Alan R; Brandstadt, Kurt F; Lawson, Rachel; Taylor, Peter G

    2010-10-21

    The potential for expanding the variety of enzymic methods for siloxane bond formation is explored. Three enzymes, Rhizopus oryzae lipase (ROL), lysozyme and phytase are reported to catalyse the condensation of the model compound, trimethylsilanol, formed in situ from trimethylethoxysilane, to produce hexamethyldisiloxane in aqueous media at 25 °C and pH 7. Thermal denaturation and reactant inhibition experiments were conducted to better understand the catalytic role of these enzyme candidates. It was found that enzyme activities were significantly reduced following thermal treatment, suggesting a potential key-role of the enzyme active sites in the catalysis. Similarly, residue-specific modification of the key-amino acids believed to participate in the ROL catalysis also had a significant effect on the silicon bio-catalysis, indicating that the catalytic triad of the lipase may be involved during the enzyme-mediated formation of the silicon-oxygen bond. E. coli phytase was found to be particularly effective at catalysing the condensation of trimethylsilanol in a predominantly organic medium consisting of 95% acetonitrile and 5% water. Whereas the use of enzymes in silicon chemistry is still very much a developing and frontier activity, the results presented herein give some grounds for optimism that the variety of enzyme mediated reactions will continue to increase and may one day become a routine element in the portfolio of the synthetic silicon chemist.

  4. Formation and coalescence of strain localized regions in ferrite phase of DP600 steels under uniaxial tensile deformation

    Energy Technology Data Exchange (ETDEWEB)

    Alaie, A., E-mail: amir_alaie@yahoo.com [Department of Mechanical Engineering, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of); Kadkhodapour, J. [Department of Mechanical Engineering, Shahid Rajaee Teacher Training University, Tehran (Iran, Islamic Republic of); Institute for Materials Testing, Materials Science and Strength of Materials (IMWF), University of Stuttgart, Stuttgart (Germany); Ziaei Rad, S. [Department of Mechanical Engineering, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of); Asadi Asadabad, M. [Materials Research School, Isfahan (Iran, Islamic Republic of); Schmauder, S. [Institute for Materials Testing, Materials Science and Strength of Materials (IMWF), University of Stuttgart, Stuttgart (Germany)

    2015-01-19

    In this study the key factors in the creation and coalescence of strain localization regions in dual-phase steels were investigated. An in-situ tensile setup was used to follow the microscopic deformation of ferrite phase inside the microstructure of DP600 steel. The test was continued until the specimen was very close to final failure. The captured scanning electron microscopy (SEM) micrographs enabled us to directly observe the evolution of deformation bands as a contour of strain distribution in the ferrite matrix. The image processing method was used to quantify the ferrite microscopic strains; the obtained strain maps were superimposed onto the SEM micrographs. The results revealed important deformational characteristics of the microstructure at the microscopic level. It was observed that despite the formation of slip bands inside the large grains during the early stages of deformation, the large ferrite grains did not contribute to the formation of high-strain bands until the final stages of severe necking. The behavior of voids and initial defects inside the localization bands was also studied. In the final stages of deformation, cracks were observed to preferentially propagate in the direction of local deformation bands and to coalescence with each other to form the final failure lines in the microstructure. It was observed that in the final stages of deformation, the defects or voids outside the deformation bands do not contribute to the final failure mechanisms and could be considered to be of minor importance.

  5. Nicotine promotes vascular endothelial growth factor secretion by human trophoblast cells under hypoxic conditions and improves the proliferation and tube formation capacity of human umbilical endothelial cells.

    Science.gov (United States)

    Zhao, Hongbo; Wu, Lanxiang; Wang, Yahui; Zhou, Jiayi; Li, Ruixia; Zhou, Jiabing; Wang, Zehua; Xu, Congjian

    2017-04-01

    Pre-eclampsia, characterized as defective uteroplacental vascularization, remains the major cause of maternal and fetal mortality and morbidity. Previous epidemiological studies demonstrated that cigarette smoking reduced the risk of pre-eclampsia. However, the molecular mechanism remains elusive. In the present study, it is demonstrated that a low dose of nicotine decreased soluble vascular endothelial growth factor receptor 1 (sFlt1) secretion in human trophoblast cells under hypoxic conditions. Nicotine was then observed to promote vascular endothelial growth factor (VEGF) secretion by reducing sFlt1 secretion and increasing VEGF mRNA transcription. Further data showed that nicotine enhanced hypoxia-mediated hypoxia-inducible factor-1α (HIF-1α) expression and HIF-1α small interfering RNA abrogated nicotine-induced VEGF secretion, indicating that HIF-1α may be responsible for nicotine-mediated VEGF transcription under hypoxic conditions. Moreover, conditioned medium from human trophoblast cells treated with nicotine under hypoxic conditions promoted the proliferation and tube formation capacity of human umbilical endothelial cells (HUVEC) by promoting VEGF secretion. These findings indicate that nicotine may promote VEGF secretion in human trophoblast cells under hypoxic conditions by reducing sFlt1 secretion and up-regulating VEGF transcription and improve the proliferation and tube formation of HUVEC cells, which may contribute to elucidate the protective effect of cigarette smoking against pre-eclampsia. Copyright © 2017 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

  6. Biogenic amine formation in turkey meat under modified atmosphere packaging with extended shelf life: Index of freshness.

    Science.gov (United States)

    Fraqueza, M J; Alfaia, C M; Barreto, A S

    2012-06-01

    The aim of this study was to evaluate the effect of modified atmosphere packaging (MAP) on biogenic amine production in turkey meat according to its shelf life period, determining an index of freshness. Sliced meat samples of different meat quality categories (according to color and pH₂₄) were individually packaged under aerobiosis (aerobic package) and in 6 different modified atmospheres containing different gas mixtures: MAP1, 50% N₂/50% CO₂; MAP2, 0.5% CO/50% CO₂/49.5% N₂; MAP3, 50% Ar/50% N₂; MAP4, 0.5% CO/80% CO₂/19.5% N₂; MAP5, 100% N₂; and MAP6, 50% Ar/50% CO₂. All samples were stored at 0 ± 1°C in the dark for between 12 and 25 d. Meat samples packaged in aerobic packaging were analyzed for their microbial and physicochemical characteristics on d 0, 5, and 12 of storage, and then extended to 19 and 25 d when samples were under MAP. The production of biogenic amines analyzed in turkey meat increased over time. The values of putrescine, cadaverine, and tyramine increased significantly (P < 0.05) during storage time in samples packaged under aerobiosis, MAP3, and MAP5. Histamine was not detected in turkey meat packaged under study conditions, or when present, the levels were below the limit of quantification (1.03 mg/kg). Tyramine in turkey meat under MAP was not the best amine indicator of meat deterioration, with cadaverine being suggested instead, or the sum of the amines putrescine, cadaverine, and tyramine, to characterize and quantify meat freshness. After 25 d of storage, the meat packaged under MAP with a mixture containing a higher concentration of CO₂ and with CO was the one with a lower index value (11.36 mg/kg), although not significantly different from the indices provided by the meat packaged with MAP1, 2, and 6.

  7. Molecular pathological epidemiology gives clues to paradoxical findings.

    Science.gov (United States)

    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.

  8. Implementing Parrondo's paradox with two-coin quantum walks

    Science.gov (United States)

    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.

  9. Effect of Sodium Chloride on α-Dicarbonyl Compound and 5-Hydroxymethyl-2-furfural Formations from Glucose under Caramelization Conditions: A Multiresponse Kinetic Modeling Approach.

    Science.gov (United States)

    Kocadağlı, Tolgahan; Gökmen, Vural

    2016-08-17

    This study aimed to investigate the kinetics of α-dicarbonyl compound formation in glucose and glucose-sodium chloride mixture during heating under caramelization conditions. Changes in the concentrations of glucose, fructose, glucosone, 1-deoxyglucosone, 3-deoxyglucosone, 3,4-dideoxyglucosone, 5-hydroxymethyl-2-furfural (HMF), glyoxal, methylglyoxal, and diacetyl were determined. A comprehensive reaction network was built, and the multiresponse model was compared to the experimentally observed data. Interconversion between glucose and fructose became 2.5 times faster in the presence of NaCl at 180 and 200 °C. The effect of NaCl on the rate constants of α-dicarbonyl compound formation varied across the precursor and the compound itself and temperature. A decrease in rate constants of 3-deoxyglucosone and 1-deoxyglucosone formations by the presence of NaCl was observed. HMF formation was revealed to be mainly via isomerization to fructose and dehydration over cyclic intermediates, and the rate constants increase 4-fold in the presence of NaCl.

  10. A theoretical insight into H accumulation and bubble formation by applying isotropic strain on the W-H system under a fusion environment

    Science.gov (United States)

    Han, Quan-Fu; Liu, Yue-Lin; Zhang, Ying; Ding, Fang; Lu, Guang-Hong

    2018-04-01

    The solubility and bubble formation of hydrogen (H) in tungsten (W) are crucial factors for the application of W as a plasma-facing component under a fusion environment, but the data and mechanism are presently scattered, indicating some important factors might be neglected. High-energy neutron-irradiated W inevitably causes a local strain, which may change the solubility of H in W. Here, we performed first-principles calculations to predict the H solution behaviors under isotropic strain combined with temperature effect in W and found that the H solubility in interstitial lattice can be promoted/impeded by isotropic tensile/compressive strain over the temperature range 300-1800 K. The calculated H solubility presents good agreement with the experiment. Together, our previous results of anisotropic strain, except for isotropic compression, both isotropic tension and anisotropic tension/compression enhance H solution so as to reveal an important physical implication for H accumulation and bubble formation in W: strain can enhance H solubility, resulting in the preliminary nucleation of H bubble that further causes the local strain of W lattice around H bubble, which in turn improves the H solubility at the strained region that promotes continuous growth of the H bubble via a chain-reaction effect in W. This result can also interpret the H bubble formation even if no radiation damage is produced in W exposed to low-energy H plasma.

  11. Formation of metabolites during biodegradation of linear alkylbenzene sulfonate in an upflow anaerobic sludge bed reactor under thermophilic conditions

    DEFF Research Database (Denmark)

    Mogensen, Anders Skibsted; Ahring, Birgitte Kiær

    2002-01-01

    Biodegradation of linear alkylbenzene sulfonate (LAS) was shown in an upflow anaerobic sludge blanket reactor under thermophilic conditions. The reactor was inoculated with granular biomass and fed with a synthetic medium and 3 mumol/L of a mixture of LAS with alkylchain length of 10 to 13 carbon...

  12. Leaf surface wax is a source of plant methane formation under UV radiation and in the presence of oxygen

    DEFF Research Database (Denmark)

    Bruhn, Dan; Mikkelsen, Teis Nørgaard; Rolsted, M. M. M.

    2014-01-01

    The terrestrial vegetation is a source of UV radiation-induced aerobic methane (CH4) release to the atmosphere. Hitherto pectin, a plant structural component, has been considered as the most likely precursor for this CH4 release. However, most of the leaf pectin is situated below the surface wax...... layer, and UV transmittance of the cuticle differs among plant species. In some species, the cuticle effectively absorbs and/or reflects UV radiation. Thus, pectin may not necessarily contribute substantially to the UV radiation-induced CH4 emission measured at surface level in all species. Here, we...... investigated the potential of the leaf surface wax itself as a source of UV radiationinduced leaf aerobic CH4 formation. Isolated leaf surface wax emitted CH4 at substantial rates in response to UV radiation. This discovery has implications for how the phenomenon should be scaled to global levels. In relation...

  13. Planktonic replication is essential for biofilm formation by Legionella pneumophila in a complex medium under static and dynamic flow conditions

    DEFF Research Database (Denmark)

    Mampel, J.; Spirig, T.; Weber, S.S.

    2006-01-01

    Legionella pneumophila persists for a long time in aquatic habitats, where the bacteria associate with biofilms and replicate within protozoan predators. While L. pneumophila serves as a paradigm for intracellular growth within protozoa, it is less clear whether the bacteria form or replicate......A mutant lacking the alternative sigma factor sigma(28) was reduced, which demonstrated that bacterial factors are required. Accumulation of biomass coincided with an increase in the optical density at 600 nm and ceased when the bacteria reached the stationary growth phase. L. pneumophila neither grew nor......, and no sizeable patches of clonally growing bacteria were observed. Our findings indicate that biofilm formation by L. pneumophila in a rich medium is due to growth of planktonic bacteria rather than to growth of sessile bacteria. In agreement with this conclusion, GFP-labeled L. pneumophila initially adhered...

  14. Could cheese be the missing piece in the French paradox puzzle?

    Science.gov (United States)

    Petyaev, Ivan M; Bashmakov, Yuriy K

    2012-12-01

    The low rates of cardiovascular mortality which have existed in France for decades despite high saturated fat consumption constitute an epidemiological phenomenon called the "French paradox". This phenomenon was originally attributed to consumption of red wine and its major constituent resveratrol. However, recent studies have revealed the limitations of this link outside France. These observations indicate that consumption of red wine alone cannot explain the paradox and perhaps some other constituents of the typical French diet could be responsible for reduced cardiovascular mortality. We hypothesize that cheese consumption, especially of molded varieties, may contribute to the occurrence of the "French paradox". This assumption is well supported by newly discovered facts revealing the positive effect of cheese ingestion on lipoprotein turnover and plasma lipid profile, haemorheological parameters and inflammatory status. Recent advances in cheese proteomics have allowed the identification and isolation of novel peptides capable of inhibiting the angiotensin-converting enzyme which controls systemic blood pressure. A complex time-dependent enzymatic transformation of the cheese core controlled by probiota, temperature and humidity during the ripening process has been shown to result in the formation of substances reducing major pro-inflammatory markers and cytokines (C-reactive protein, interleukin 6, tumor necrosis factor alpha). Molded cheeses, including Roquefort, may be even more favorable to cardiovascular health due to the presence of secondary metabolites produced by Penicillium roqueforti and other fungi. Among them are andrastins A-D and roquefortine, whose ability to inhibit cholesterol biosynthesis and bacterial growth may be a key mechanism in the prevention of cardiovascular disease. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. The mechanisms underlying corrosion product formation and deposition in nuclear power plant circuits through the action of galvanic and thermal electromotive forces

    International Nuclear Information System (INIS)

    Brusakov, V.P.; Sedov, V.M.; Khitrov, Yu.A.; Brusov, K.N.; Razmashkin, N.V.; Versin, V.V.; Rybalchenko, I.L.

    1983-01-01

    From a theoretical standpoint, the processes of formation of corrosion products in nuclear power plant circuits, deposition of corrosion products on the circuit surfaces, formation of an equilibrium concentration of corrosion products in the coolant, and distribution of radionuclides resulting from corrosion in different parts of the circuit are considered. It is shown that the main driving forces for the mass-transfer processes in the circuits are the thermal and galvanic electromotive forces (EMF) of the microcouples. On the basis of the theoretical concepts developed the authors have obtained analytical dependences for calculating the individual stages of the process of corrosion product transfer in the circuits. The mechanisms underlying the processes which occur as a result of thermal and galvanic EMFs are considered, together with the factors influencing these processes. The results of verification of the dependences by computational methods are given and they are compared with operational data from nuclear and conventional thermal power plants and with experimental data. (author)

  16. Four twins for a paradox: on "sensitive" twins and the biological counterpart of the "twin paradox".

    Science.gov (United States)

    Ascioti, Fortunato A

    2009-03-01

    Monozygotic twin (MZT) epigenetic development, i.e., aging, diverges largely in time despite the initially very small genetic differences between MZTs. This fact is interpreted as a "sensitivity to initial conditions" phenomenon, a common property of either deterministic or stochastic chaotic systems. Some of the biotheoretical implications stemming from this empirical observation are briefly discussed here, while an actual measure of MZT epigenetic time divergence is given through an estimate of the (Stochastic) Lyapunov exponents (LEs) (i.e., the rate of exponential time divergence). These results suggest a reconsideration of the Langevin-Einstein thought experiment known as the "twin paradox." At least four twins are necessary in order to take into account the inertially independent divergent aging described here. Alternatively, LE estimates, like those given here, should be used. Finally suggested in the actual special-relativity experiments is the replacement of clocks with some nonlinear (chaotic) forced oscillator.

  17. The Colombian Left: A Paradoxical Past; A Promising Future?

    Directory of Open Access Journals (Sweden)

    Charles Bergquist

    2017-07-01

    Full Text Available The essay explores the paradoxical history of the left in Colombia: how and why one of the weakest lefts in Latin America brought about the strongest and most lasting Marxist insurrection in the hemisphere in the decades following the Cuban Revolution. The article argues that the terms of this paradox are related, that the historic weakness of the left partly explains the force and longevity of revolutionary guerrillas, and that said paradox helps clarify not only the failure of several attempts to achieve a negotiated settlement of the armed conflict, but also the negative vote in the October 2016 plebiscite. Finally, it envisions a more promising future for the country’s left, provided that a lasting peace is consolidated.

  18. Paradoxes in virtual team knowledge communication and trust building

    DEFF Research Database (Denmark)

    Petersen, Nils Braad

    2012-01-01

    This thesis proposal presents paradoxes within current trust and knowledge management literatures as a lens for understanding challenges in virtual teams working across organisational and geographic boundaries. By exposing contradictions within current virtual team research, the author proposes...... a need for a different, multi-level, multi-theoretical approach to virtual team research in order to overcome the paradoxes. A moderate constructionist research position building on Critical Realism is proposed. To situate the project within current literatures, trust, knowledge management and virtual...... team literatures are reviewed. These are used to support the paradoxes used as a lens for understanding. A research design is presented building on interviews, documentary analysis and observations analysed using Social Network Analysis and James Gee’s framework for discourse analysis. Finally...

  19. Preliminary analyses of scenarios for potential human interference for repositories in three salt formations

    Energy Technology Data Exchange (ETDEWEB)

    1985-10-01

    Preliminary analyses of scenarios for human interference with the performance of a radioactive waste repository in a deep salt formation are presented. The following scenarios are analyzed: (1) the U-Tube Connection Scenario involving multiple connections between the repository and the overlying aquifer system; (2) the Single Borehole Intrusion Scenario involving penetration of the repository by an exploratory borehole that simultaneously connects the repository with overlying and underlying aquifers; and (3) the Pressure Release Scenario involving inflow of water to saturate any void space in the repository prior to creep closure with subsequent release under near lithostatic pressures following creep closure. The methodology to evaluate repository performance in these scenarios is described and this methodology is applied to reference systems in three candidate formations: bedded salt in the Palo Duro Basin, Texas; bedded salt in the Paradox Basin, Utah; and the Richton Salt Dome, Mississippi, of the Gulf Coast Salt Dome Basin.

  20. Preliminary analyses of scenarios for potential human interference for repositories in three salt formations

    International Nuclear Information System (INIS)

    1985-10-01

    Preliminary analyses of scenarios for human interference with the performance of a radioactive waste repository in a deep salt formation are presented. The following scenarios are analyzed: (1) the U-Tube Connection Scenario involving multiple connections between the repository and the overlying aquifer system; (2) the Single Borehole Intrusion Scenario involving penetration of the repository by an exploratory borehole that simultaneously connects the repository with overlying and underlying aquifers; and (3) the Pressure Release Scenario involving inflow of water to saturate any void space in the repository prior to creep closure with subsequent release under near lithostatic pressures following creep closure. The methodology to evaluate repository performance in these scenarios is described and this methodology is applied to reference systems in three candidate formations: bedded salt in the Palo Duro Basin, Texas; bedded salt in the Paradox Basin, Utah; and the Richton Salt Dome, Mississippi, of the Gulf Coast Salt Dome Basin

  1. Optimisation of Surface-Initiated Photoiniferter-Mediated Polymerisation under Confinement, and the Formation of Block Copolymers in Mesoporous Films

    Directory of Open Access Journals (Sweden)

    Jessica C. Tom

    2017-10-01

    Full Text Available Nature as the ultimate inspiration can direct, gate, and selectively transport species across channels to fulfil a specific targeted function. Harnessing such precision over local structure and functionality at the nanoscale is expected to lead to indispensable developments in synthetic channels for application in catalysis, filtration and sensing, and in drug delivery. By combining mesoporous materials with localised charge-switchable poly(2-(dimethylaminoethyl methacrylate (PDMAEMA brushes, precisely controlling pore filling and exploring the possibility of incorporating two different responsive polymers, we hope to approach the precision control of natural systems in the absence of an external force. Here, we report a simple one-step approach to prepare a mesoporous silica thin film with ~8 nm pores functionalised with a photoiniferter by combining sol–gel chemistry and evaporation-induced self-assembly (EISA. We show that surface-initiated photoiniferter-mediated polymerisation (SI-PIMP allows the incorporation of a high polymer content up to geometrical pore blocking by the simple application of UV light in the presence of a monomer and solvent, proceeding in a controlled manner in pore sizes below 10 nm, with the potential to tune the material properties through the formation of surface-grafted block copolymers.

  2. The cyanobacterial nitrogen fixation paradox in natural waters.

    Science.gov (United States)

    Paerl, Hans

    2017-01-01

    Nitrogen fixation, the enzymatic conversion of atmospheric N (N 2 ) to ammonia (NH 3 ), is a microbially mediated process by which "new" N is supplied to N-deficient water bodies. Certain bloom-forming cyanobacterial species are capable of conducting N 2 fixation; hence, they are able to circumvent N limitation in these waters. However, this anaerobic process is highly sensitive to oxygen, and since cyanobacteria produce oxygen in photosynthesis, they are faced with a paradoxical situation, where one critically important (for supporting growth) biochemical process is inhibited by another. N 2 -fixing cyanobacterial taxa have developed an array of biochemical, morphological, and ecological adaptations to minimize the "oxygen problem"; however, none of these allows N 2 fixation to function at a high enough efficiency so that it can supply N needs at the ecosystem scale, where N losses via denitrification, burial, and advection often exceed the inputs of "new" N by N 2 fixation. As a result, most marine and freshwater ecosystems exhibit chronic N limitation of primary production. Under conditions of perpetual N limitation, external inputs of N from human sources (agricultural, urban, and industrial) play a central role in determining ecosystem fertility and, in the case of N overenrichment, excessive primary production or eutrophication. This points to the importance of controlling external N inputs (in addition to traditional phosphorus controls) as a means of ensuring acceptable water quality and safe water supplies. Nitrogen fixation, the enzymatic conversion of atmospheric N 2 to ammonia (NH 3 ) is a  microbially-mediated process by which "new" nitrogen is supplied to N-deficient water bodies.  Certain bloom-forming cyanobacterial species are capable of conducting N 2 fixation; hence they are able to circumvent nitrogen limitation in these waters. However, this anaerobic process is highly sensitive to oxygen, and since cyanobacteria produce oxygen in

  3. Herbart paradoxal ? La lecture de Cassirer

    OpenAIRE

    Maigné, Carole

    2012-01-01

    Cet article voudrait éclaircir le paradoxe que Ernst Cassirer décèle chez Johann Friedrich Herbart, auquel il consacre un chapitre dense du volume 3 de son histoire de la philosophie : Le Problème de la connaissance. Il nous semble que le paradoxe se dénoue si Herbart est inscrit dans l’histoire même des écrits de Cassirer, depuis Substance et Fonction jusqu’à la Philosophie des formes symboliques : alors que Herbart s’inscrit pleinement dans cette ontologie fonctionnelle que décrit et promeu...

  4. R and D Policies, Carbon Tax and Green Paradox

    International Nuclear Information System (INIS)

    Bermudez Neubauer, Mauricio; Grimaud, Andre; Rouge, Luc

    2016-01-01

    We study an economy in which a final good is produced by two sectors. One uses a non-renewable and polluting resource, the other a renewable and clean resource. A specific type of research is associated with each sector. The public authorities levy a carbon tax and simultaneously subsidise both research sectors. We study the impact of such a policy scheme on the rate of resource extraction and emissions. In the clean sector, the research subsidy and the carbon tax have opposite effects. If the tax creates a green paradox, the subsidy moderates it; if the tax slows resource extraction, then the subsidy generates a green paradox

  5. Size-controlled synthesis and formation mechanism of manganese oxide OMS-2 nanowires under reflux conditions with KMnO4 and inorganic acids

    Science.gov (United States)

    Zhang, Qin; Cheng, Xiaodi; Qiu, Guohong; Liu, Fan; Feng, Xionghan

    2016-05-01

    This study presents a simplified approach for size-controlled synthesis of manganese oxide octahedral molecular sieve (OMS-2) nanowires using potassium permanganate (KMnO4) and different inorganic acids (HCl, HNO3, and H2SO4) under reflux conditions. The morphology and nanostructure of the synthesized products are characterized by X-ray diffraction, Ar adsorption, and electron microscopy analysis, in order to elucidate the controlling effects of acid concentration and type as well as the formation mechanism of OMS-2 nanowires. The concentration of inorganic acid is a crucial factor controlling the phase of the synthesized products. OMS-2 nanowires are obtained with HCl at the concentration ≥0.96 mol/L or with HNO3 and H2SO4 at the concentrations ≥0.72 mol/L. Differently, the type of inorganic acid effectively determines the particle size of OMS-2 nanowires. When the acid is changed from HCl to HNO3 and H2SO4 in the reflux system, the average length of OMS-2 declines significantly by 60-70% (1104-442 and 339 nm), with minor decreased in the average width (43-39 and 34 nm). The formation of OMS-2 nanowires under reflux conditions with KMnO4 and inorganic acids involves a two-step process, i.e., the initial formation of layered manganese oxides, and subsequent transformation to OMS-2 via a dissolution-recrystallization process under acidic conditions. The proposed reflux route provides an alternative approach for synthesizing OMS-2 nanowires as well as other porous nano-crystalline OMS materials.

  6. The Arabidopsis Transcription Factor MYB112 Promotes Anthocyanin Formation during Salinity and under High Light Stress1[OPEN

    Science.gov (United States)

    Lotkowska, Magda E.; Tohge, Takayuki; Fernie, Alisdair R.; Xue, Gang-Ping; Balazadeh, Salma; Mueller-Roeber, Bernd

    2015-01-01

    MYB transcription factors (TFs) are important regulators of flavonoid biosynthesis in plants. Here, we report MYB112 as a formerly unknown regulator of anthocyanin accumulation in Arabidopsis (Arabidopsis thaliana). Expression profiling after chemically induced overexpression of MYB112 identified 28 up- and 28 down-regulated genes 5 h after inducer treatment, including MYB7 and MYB32, which are both induced. In addition, upon extended induction, MYB112 also positively affects the expression of PRODUCTION OF ANTHOCYANIN PIGMENT1, a key TF of anthocyanin biosynthesis, but acts negatively toward MYB12 and MYB111, which both control flavonol biosynthesis. MYB112 binds to an 8-bp DNA fragment containing the core sequence (A/T/G)(A/C)CC(A/T)(A/G/T)(A/C)(T/C). By electrophoretic mobility shift assay and chromatin immunoprecipitation coupled to quantitative polymerase chain reaction, we show that MYB112 binds in vitro and in vivo to MYB7 and MYB32 promoters, revealing them as direct downstream target genes. We further show that MYB112 expression is up-regulated by salinity and high light stress, environmental parameters that both require the MYB112 TF for anthocyanin accumulation under these stresses. In contrast to several other MYB TFs affecting anthocyanin biosynthesis, MYB112 expression is not controlled by nitrogen limitation or an excess of carbon. Thus, MYB112 constitutes a regulator that promotes anthocyanin accumulation under abiotic stress conditions. PMID:26378103

  7. Formation mechanism of 3D macroporous graphene aerogel in alcohol-water media under gamma-ray radiation

    Science.gov (United States)

    Wang, Weikang; Wu, Yihu; Jiang, Zhiwen; Wang, Mozhen; Wu, Qichao; Zhou, Xiao; Ge, Xuewu

    2018-01-01

    The subtle control on the self-assembly behavior of graphene oxide (GO) nanosheets is one of effective ways for the preparation of high-performance macroscopic graphene-based materials. In this work, detailed characterizations and discussion on the morphological and compositional changes on the solid products in various alcohol-water dispersions of GO under γ-ray radiation were carried out, proving the concurrent hydroxyalkylation and reduction processes of GO nanosheets in the system, which triggered the spontaneous self-assembly of the hydroxyalkylated and reduced GO nanosheets (HA-rGO). The pH and the volume ratio of alcohol to water (ϕa/w) are the key factors to control the self-assembly of the HA-rGO sheets. A free-standing graphene hydrogel (GH) only forms in the strong acid alcohol-water media with an appropriate ϕa/w. After the freeze-drying of the GH, a macroporous graphene aerogel (GA) was obtained, which exhibited a high absorption performance for not only nonpolar molecules (cyclohexane and kerosene), but also most polar molecules (toluene, chloroform, glycol, etc). This work demonstrates a comprehensive self-assembly mechanism of GO nanosheets in an aqueous media under γ-ray radiation and reveals that GA produced from the reduction of GO can be used as potential super-adsorbents for not only waste oil, but also the polar alcohols.

  8. An Experimental and Computational Study on Soot Formation in a Coflow Jet Flame Under Microgravity and Normal Gravity

    Science.gov (United States)

    Ma, Bin; Cao, Su; Giassi, Davide; Stocker, Dennis P.; Takahashi, Fumiaki; Bennett, Beth Anne V.; Smooke, Mitchell D.; Long, Marshall B.

    2014-01-01

    Upon the completion of the Structure and Liftoff in Combustion Experiment (SLICE) in March 2012, a comprehensive and unique set of microgravity coflow diffusion flame data was obtained. This data covers a range of conditions from weak flames near extinction to strong, highly sooting flames, and enabled the study of gravitational effects on phenomena such as liftoff, blowout and soot formation. The microgravity experiment was carried out in the Microgravity Science Glovebox (MSG) on board the International Space Station (ISS), while the normal gravity experiment was performed at Yale utilizing a copy of the flight hardware. Computational simulations of microgravity and normal gravity flames were also carried out to facilitate understanding of the experimental observations. This paper focuses on the different sooting behaviors of CH4 coflow jet flames in microgravity and normal gravity. The unique set of data serves as an excellent test case for developing more accurate computational models.Experimentally, the flame shape and size, lift-off height, and soot temperature were determined from line-of-sight flame emission images taken with a color digital camera. Soot volume fraction was determined by performing an absolute light calibration using the incandescence from a flame-heated thermocouple. Computationally, the MC-Smooth vorticity-velocity formulation was employed to describe the chemically reacting flow, and the soot evolution was modeled by the sectional aerosol equations. The governing equations and boundary conditions were discretized on an axisymmetric computational domain by finite differences, and the resulting system of fully coupled, highly nonlinear equations was solved by a damped, modified Newtons method. The microgravity sooting flames were found to have lower soot temperatures and higher volume fraction than their normal gravity counterparts. The soot distribution tends to shift from the centerline of the flame to the wings from normal gravity to

  9. Formation of metabolites during biodegradation of linear alkylbenzene sulfonate in an upflow anaerobic sludge bed reactor under thermophilic conditions

    DEFF Research Database (Denmark)

    Mogensen, Anders Skibsted; Ahring, Birgitte Kiær

    2002-01-01

    , the removal of LAS in the reactor inoculated with active granular biomass exceeded the removal in the sterile reactor inoculated with sterile granular biomass. The effect of sorption ceased after 185 to 555 h depending on the LAS homologs. 40% of the LAS was biodegraded, and the removal rate was 0.5 x 10......Biodegradation of linear alkylbenzene sulfonate (LAS) was shown in an upflow anaerobic sludge blanket reactor under thermophilic conditions. The reactor was inoculated with granular biomass and fed with a synthetic medium and 3 mumol/L of a mixture of LAS with alkylchain length of 10 to 13 carbon...... atoms. The reactor was operated with a hydraulic retention time of 12 h with effluent recirculation in an effluent to influent ratio of 5 to 1. A sterile reactor operated in parallel revealed that sorption to sludge particles initially accounted for a major LAS removal. After 8 days of reactor operation...

  10. Formation of Acetylene in the Reaction of Methane with Iron Carbide Cluster Anions FeC3- under High-Temperature Conditions.

    Science.gov (United States)

    Li, Hai-Fang; Jiang, Li-Xue; Zhao, Yan-Xia; Liu, Qing-Yu; Zhang, Ting; He, Sheng-Gui

    2018-03-01

    The underlying mechanism for non-oxidative methane aromatization remains controversial owing to the lack of experimental evidence for the formation of the first C-C bond. For the first time, the elementary reaction of methane with atomic clusters (FeC 3 - ) under high-temperature conditions to produce C-C coupling products has been characterized by mass spectrometry. With the elevation of temperature from 300 K to 610 K, the production of acetylene, the important intermediate proposed in a monofunctional mechanism of methane aromatization, was significantly enhanced, which can be well-rationalized by quantum chemistry calculations. This study narrows the gap between gas-phase and condensed-phase studies on methane conversion and suggests that the monofunctional mechanism probably operates in non-oxidative methane aromatization. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Regulating pesticides in food: the Delaney paradox

    National Research Council Canada - National Science Library

    National Research Council Staff

    ... and Agricultural Innovation Board on Agriculture National Research Council NATIONAL ACADEMY PRESS Washington, D.C. 1987 i Copyrightthe cannot be not from book, paper however, version for formatting, original authoritative the typesetting-specific the as from created publication files XML from other this and of recomposed styles, version h...

  12. The Role of Carbon in Core Formation Under Highly Reducing Conditions With Implications for the Planet Mercury

    Science.gov (United States)

    Vander Kaaden, Kathleen E..; McCubbin, Francis M.; Ross, D. Kent; Draper, David S.

    2017-01-01

    Results from the MErcury Surface, Space ENvironment, GEochemistry and Ranging (MESSENGER) spacecraft have shown elevated abundances of carbon on the surface of Mercury. Furthermore, the X-Ray Spectrometer on board MESSENGER measured elevated abundances of sulfur and low abundances of iron, suggesting the planet's oxygen fugacity (fO2) is several log10 units below the Iron-Wüstite (IW) buffer. Similar to the role of other volatiles (e.g. sulfur) on highly reducing planetary bodies, carbon is expected to behave differently than it would under higher fO2. As discussed by Nittler et al. and Hauck et al., under such highly reducing conditions, the majority of the iron partitions into the core. On Mercury, this resulted in a relatively large core and a thin mantle. Using a composition similar to the largest volcanic field on the planet (the northern volcanic plains), Vander Kaaden and McCubbin conducted sink-float experiments to determine the density of melts and minerals on Mercury. They showed that graphite would be the only buoyant mineral in a mercurian magma ocean. Therefore, Vander Kaaden and McCubbin proposed a possible primary flotation crust on the planet composed of graphite. Concurrently, Peplowski et al. used GRS data from MESSENGER to show an average northern hemisphere abundance of C on the planet of 1.4 +/- 0.9 wt%. However, as this result was only at the one-sigma detection limit, possible carbon abundances at the three-sigma detection limit for Mercury range from 0 to 4.1 wt% carbon. Additionally, Murchie et al. investigated the possible darkening agent on Mercury and concluded that coarse-grained graphite could darken high reflectance plains to the low reflectance material. To further test the possibility of elevated abundances of carbon in Mercury's crust, Peplowski et al. used the low-altitude MESSENGER data to show that carbon is the only material consistent with both the visible to near-infrared spectra and the neutron measurements of low

  13. Activity Clamp Provides Insights into Paradoxical Effects of the Anti-Seizure Drug Carbamazepine.

    Science.gov (United States)

    Morris, Gareth; Leite, Marco; Kullmann, Dimitri M; Pavlov, Ivan; Schorge, Stephanie; Lignani, Gabriele

    2017-05-31

    A major challenge in experimental epilepsy research is to reconcile the effects of anti-epileptic drugs (AEDs) on individual neurons with their network-level actions. Highlighting this difficulty, it is unclear why carbamazepine (CBZ), a frontline AED with a known molecular mechanism, has been reported to increase epileptiform activity in several clinical and experimental studies. We confirmed in an in vitro mouse model (in both sexes) that the frequency of interictal bursts increased after CBZ perfusion. To address the underlying mechanisms, we developed a method, activity clamp, to distinguish the response of individual neurons from network-level actions of CBZ. We first recorded barrages of synaptic conductances from neurons during epileptiform activity and then replayed them in pharmacologically isolated neurons under control conditions and in the presence of CBZ. CBZ consistently decreased the reliability of the second action potential in each burst of activity. Conventional current-clamp recordings using excitatory ramp or square-step current injections failed to reveal this effect. Network modeling showed that a CBZ-induced decrease of neuron recruitment during epileptic bursts can lead to an increase in burst frequency at the network level by reducing the refractoriness of excitatory transmission. By combining activity clamp with computer simulations, the present study provides a potential explanation for the paradoxical effects of CBZ on epileptiform activity. SIGNIFICANCE STATEMENT The effects of anti-epileptic drugs on individual neurons are difficult to separate from their network-level actions. Although carbamazepine (CBZ) has a known anti-epileptic mechanism, paradoxically, it has also been reported to increase epileptiform activity in clinical and experimental studies. To investigate this paradox during realistic neuronal epileptiform activity, we developed a method, activity clamp, to distinguish the effects of CBZ on individual neurons from network

  14. Pipette-based Method to Study Embryoid Body Formation Derived from Mouse and Human Pluripotent Stem Cells Partially Recapitulating Early Embryonic Development Under Simulated Microgravity Conditions

    Science.gov (United States)

    Shinde, Vaibhav; Brungs, Sonja; Hescheler, Jürgen; Hemmersbach, Ruth; Sachinidis, Agapios

    2016-06-01

    The in vitro differentiation of pluripotent stem cells partially recapitulates early in vivo embryonic development. More recently, embryonic development under the influence of microgravity has become a primary focus of space life sciences. In order to integrate the technique of pluripotent stem cell differentiation with simulated microgravity approaches, the 2-D clinostat compatible pipette-based method was experimentally investigated and adapted for investigating stem cell differentiation processes under simulated microgravity conditions. In order to keep residual accelerations as low as possible during clinorotation, while also guaranteeing enough material for further analysis, stem cells were exposed in 1-mL pipettes with a diameter of 3.5 mm. The differentiation of mouse and human pluripotent stem cells inside the pipettes resulted in the formation of embryoid bodies at normal gravity (1 g) after 24 h and 3 days. Differentiation of the mouse pluripotent stem cells on a 2-D pipette-clinostat for 3 days also resulted in the formation of embryoid bodies. Interestingly, the expression of myosin heavy chain was downregulated when cultivation was continued for an additional 7 days at normal gravity. This paper describes the techniques for culturing and differentiation of pluripotent stem cells and exposure to simulated microgravity during culturing or differentiation on a 2-D pipette clinostat. The implementation of these methodologies along with -omics technologies will contribute to understand the mechanisms regulating how microgravity influences early embryonic development.

  15. Microbial mediated soil structure formation under wetting and drying cycles along a climate gradient (arid to humid) on hillslopes in Chile

    Science.gov (United States)

    Bernhard, Nadine; Moskwa, Lisa-Marie; Kühn, Peter; Mueller, Carsten W.; Wagner, Dirk; Scholten, Thomas

    2017-04-01

    It is well-known that the land surface resistance against erosion is largely controlled by the structure stability of the soil given by its inherent properties. Microbial activity plays a vital role in soil structure development, and thus affecting soil physical parameters. Accordingly the influence of biota shaping the earth's surface has been described through mechanisms such as mineral weathering, formation of ions and biofilms controlling land surface resistance against erosion. However the role of microorganisms for the development of soil stabilizing properties is still unclear and a precise quantitative understanding of the mechanisms under different climate conditions is widely missing. The objectives of our study are to examine to which extend microbiological processes control soil structure formation and stability and whether this is influenced by climate and topographic position. Soil samples were taken along a climate gradient and from different topographic positions of hillslopes in the Chilean Coastal Cordillera in austral autumn 2016. The variables of lithology, human disturbances and relief were held as far as possible constant whereas climate varies along the transect. We implemented 10 wet-dry cycles on air dried and sieved natural and sterile samples to enhance particle aggregation and increase structure stability. Throughout the entire experiment temperature is held constant at 20 °C to avoid changes in microbial activity. Samples are moistened and dried and each kept at the same respective pF-values for the same duration to add the same stress to each sample. Aggregate stability will be measured using wet sieving, ultrasonic dispersion and simulated rainfall. The results will be compared with on-site rainfall simulation experiments on hillslopes in the Chilean Coastal Cordillera to link laboratory results with natural field conditions. The experiment gives first insight into the aggregate formation process over time with and without

  16. Experimental evidence of formation of transparent exopolymer particles (TEP) and POC export provoked by dust addition under current and high pCO2 conditions.

    Science.gov (United States)

    Louis, Justine; Pedrotti, Maria Luiza; Gazeau, Frédéric; Guieu, Cécile

    2017-01-01

    The evolution of organic carbon export to the deep ocean, under anthropogenic forcing such as ocean warming and acidification, needs to be investigated in order to evaluate potential positive or negative feedbacks on atmospheric CO2 concentrations, and therefore on climate. As such, modifications of aggregation processes driven by transparent exopolymer particles (TEP) formation have the potential to affect carbon export. The objectives of this study were to experimentally assess the dynamics of organic matter, after the simulation of a Saharan dust deposition event, through the measurement over one week of TEP abundance and size, and to evaluate the effects of ocean acidification on TEP formation and carbon export following a dust deposition event. Three experiments were performed in the laboratory using 300 L tanks filled with filtered seawater collected in the Mediterranean Sea, during two 'no bloom' periods (spring at the start of the stratification period and autumn at the end of this stratification period) and during the winter bloom period. For each experiment, one of the two tanks was acidified to reach pH conditions slightly below values projected for 2100 (~ 7.6-7.8). In both tanks, a dust deposition event of 10 g m-2 was simulated at the surface. Our results suggest that Saharan dust deposition triggered the abiotic formation of TEP, leading to the formation of organic-mineral aggregates. The amount of particulate organic carbon (POC) exported was proportional to the flux of lithogenic particles to the sediment traps. Depending on the season, the POC flux following artificial dust deposition ranged between 38 and 90 mg m-2 over six experimental days. Such variability is likely linked to the seasonal differences in the quality and quantity of TEP-precursors initially present in seawater. Finally, these export fluxes were not significantly different at the completion of the three experiments between the two pH conditions.

  17. A paradox of rationality à la von Neumann-Morgenstern

    NARCIS (Netherlands)

    Ismail, M.S.

    2015-01-01

    We show that there are games and decision situations in which it is not possible for the decision maker to be rational a la von Neumann-Morgenstern in both situations simultaneously, which is the source of the paradox presented in this note. We provide an assumption which is the necessary and

  18. Generalizations of Paradoxical Results in Multidimensional Item Response Theory

    Science.gov (United States)

    Jordan, Pascal; Spiess, Martin

    2012-01-01

    Maximum likelihood and Bayesian ability estimation in multidimensional item response models can lead to paradoxical results as proven by Hooker, Finkelman, and Schwartzman ("Psychometrika" 74(3): 419-442, 2009): Changing a correct response on one item into an incorrect response may produce a higher ability estimate in one dimension.…

  19. Classical Angular Momentum of Light: A Paradox and its Resolution

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 8; Issue 10. Classical Angular Momentum of Light: A Paradox and its Resolution. K Vijay Kumar N Kumar. Classroom Volume 8 Issue 10 October 2003 pp 69-75. Fulltext. Click here to view fulltext PDF. Permanent link:

  20. MCM Paradox: Abundance of Eukaryotic Replicative Helicases and Genomic Integrity

    Directory of Open Access Journals (Sweden)

    Mitali Das

    2014-01-01

    Full Text Available As a crucial component of DNA replication licensing system, minichromosome maintenance (MCM 2–7 complex acts as the eukaryotic DNA replicative helicase. The six related MCM proteins form a heterohexamer and bind with ORC, CDC6, and Cdt1 to form the prereplication complex. Although the MCMs are well known as replicative helicases, their overabundance and distribution patterns on chromatin present a paradox called the “MCM paradox.” Several approaches had been taken to solve the MCM paradox and describe the purpose of excess MCMs distributed beyond the replication origins. Alternative functions of these MCMs rather than a helicase had also been proposed. This review focuses on several models and concepts generated to solve the MCM paradox coinciding with their helicase function and provides insight into the concept that excess MCMs are meant for licensing dormant origins as a backup during replication stress. Finally, we extend our view towards the effect of alteration of MCM level. Though an excess MCM constituent is needed for normal cells to withstand stress, there must be a delineation of the threshold level in normal and malignant cells. This review also outlooks the future prospects to better understand the MCM biology.

  1. Recent Insights into the Paradoxical Effect of Echinocandins

    Directory of Open Access Journals (Sweden)

    Johannes Wagener

    2017-12-01

    Full Text Available Echinocandin antifungals represent one of the most important drug classes for the treatment of invasive fungal infections. The mode of action of the echinocandins relies on inhibition of the β-1,3-glucan synthase, an enzyme essentially required for the synthesis of the major fungal cell wall carbohydrate β-1,3-glucan. Depending on the species, echinocandins may exert fungicidal or fungistatic activity. Apparently independent of this differential activity, a surprising in vitro phenomenon called the “paradoxical effect” can be observed. The paradoxical effect is characterized by the ability of certain fungal isolates to reconstitute growth in the presence of higher echinocandin concentrations, while being fully susceptible at lower concentrations. The nature of the paradoxical effect is not fully understood and has been the focus of multiple studies in the last two decades. Here we concisely review the current literature and propose an updated model for the paradoxical effect, taking into account recent advances in the field.

  2. Tensions and Paradoxes in Teaching: Implications for Teacher Education

    Science.gov (United States)

    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…

  3. A Paradox of Newtonian Gravitation and Laplace's Solution

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 21; Issue 5. A Paradox of Newtonian Gravitation and Laplace's Solution. General Article Volume ... A physical phenomenonthat can justify Laplace's suggestion isalso mentioned briefly. This article also posesan interesting mathematical problem that can ...

  4. Aggression; a Paradoxical pathology of the mind | Kitapondya | Dar ...

    African Journals Online (AJOL)

    Dar Es Salaam Medical Students' Journal. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 15, No 1 (2008) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. Aggression; a Paradoxical pathology of the mind.

  5. Semantic paradox. A comparative analysis of scholastic and analytic views

    Czech Academy of Sciences Publication Activity Database

    Hanke, Miroslav

    2014-01-01

    Roč. 91, č. 3 (2014), s. 367-386 ISSN 2168-9105 R&D Projects: GA ČR(CZ) GP13-08389P Institutional support: RVO:67985955 Keywords : semantic paradoxes * scholastic logic * groundlessness * circularity * semantic pathology * two-line puzzles Subject RIV: AA - Philosophy ; Religion

  6. Cajetan of Thiene on the Logic of Paradox

    Czech Academy of Sciences Publication Activity Database

    Hanke, Miroslav

    2016-01-01

    Roč. 13, č. 1 (2016), s. 71-95 ISSN 1214-8407 R&D Projects: GA ČR GP13-08389P Institutional support: RVO:67985955 Keywords : Cajetan of Thiene * logical operators * semantic paradoxes * scholastic logic Subject RIV: AA - Philosophy ; Religion

  7. A Paradox of Newtonian Gravitation and Laplace's Solution

    Indian Academy of Sciences (India)

    IAS Admin

    ment of IIT Kharagpur in the area of virtual reality. He earlier carried out research at IIEST Shibpur on orbital dynamics and gravitation. Newton's theory of gravitation solved many prob- lems of celestial mechanics but led to some major problems, one of which was that it gave rise to a serious paradox discussed in this article.

  8. Design principles of paradoxical signaling in the immune system

    Science.gov (United States)

    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.

  9. Which matrices are immune against the transportation paradox

    NARCIS (Netherlands)

    Deineko, Vladimir G.; Klinz, Bettina; Woeginger, Gerhard

    2003-01-01

    We characterize the m×n cost matrices of the transportation problem for which there exist supplies and demands such that the transportation paradox arises. Our characterization is fairly simple and can be verified within O(mn) computational steps. Moreover, we discuss the corresponding question for

  10. Apparent paradoxes in classical electrodynamics: relativistic transformation of force

    International Nuclear Information System (INIS)

    Kholmetskii, A L; Yarman, T

    2007-01-01

    In this paper, we analyse a number of paradoxical teaching problems of classical electrodynamics, dealing with the relativistic transformation of force for complex macro systems, consisting of a number of subsystems with nonzero relative velocities such as electric circuits that change their shape in the course of time

  11. A classical model explaining the OPERA velocity paradox

    CERN Document Server

    Broda, Boguslaw

    2011-01-01

    In the context of the paradoxical results of the OPERA Collaboration, we have proposed a classical mechanics model yielding the statistically measured velocity of a beam higher than the velocity of the particles constituting the beam. Ingredients of our model necessary to obtain this curious result are a non-constant fraction function and the method of the maximum-likelihood estimation.

  12. A Powerful Theory and a Paradox: Ecological Psychologists after Barker

    Science.gov (United States)

    Scott, M. M.

    2005-01-01

    Roger Barker, influenced by Lewin, developed a powerful theory in psychology, behavior setting theory. Paradoxically, this theory is still not widely known or understood in mainstream American psychology. Oral histories of the core group who worked with Barker were collected and examined to determine influences on them and subsequent directions in…

  13. A Paradoxical Academic Identity: Fate, Utopia and Critical Hope

    Science.gov (United States)

    Sutton, Paul

    2015-01-01

    Using a dialectical mode of exposition, I offer a reflexive sociological theorisation of the paradox that characterises my academic identity: a fatalistic disenchantment concerning the colonisation of Higher Education (HE) by neoliberalism co-exists with a utopianism concerning HE's emancipatory possibilities. I begin with a discussion of Weber's…

  14. Paradoxical implications of personal social media use for work

    NARCIS (Netherlands)

    van Zoonen, W.; Rice, R.E.

    2017-01-01

    New information and communication technologies can have paradoxical implications: they may be liberating and constraining at the same time. This field study examines the direct implications of personal social media use for work on employees’ autonomy and work pressure, and the indirect effects on

  15. Service Recovery Paradox In Indian Banking Industry: An Empirical Investigation

    Directory of Open Access Journals (Sweden)

    Arunesh Garg

    2013-10-01

    Full Text Available The present study examines existence of service recovery paradox in Indian banking industry. The study is taken up in the tri-city of Chandigarh, Panchkula and Mohali. The respondents are catego- rized into failure and no-failure groups on the basis of their service experience. Failure group consti- tutes those respondents who have experienced service recovery, and has been further divided into five sub-groups ranging from service recovery++ (service recovery better than expected to service recovery- - (service recovery worse than expected. Service recovery paradox is examined by com- paring service recovery++ group with no-failure group. The study shows evidence for existence of service recovery paradox in relation to satisfaction. It has been concluded that for service recovery paradox to exist, recovery effort has to be exceptionally good and much better than expectation level of the customer. The study suggests that service managers should take service failure as an opportunity to appease customers by providing a much better than expected recovery experience. However, organizations should not plan to create service failure situations because if they falter on imparting the recovery, customer satisfaction may be influenced negatively.

  16. Climate policy and nonrenewable resources : The green paradox and beyond

    NARCIS (Netherlands)

    Pittel, Karen; van der Ploeg, Rick; Withagen, Cees

    2014-01-01

    Recent developments suggest that well-intended climate policies–including carbon taxes and subsidies for renewable energy – might not accomplish what policy makers intend. Hans-Werner Sinn has described a "green paradox," arguing that these policies could hasten global warming by encouraging owners

  17. Paradox of Our Times: Hunger in a Strong Economy.

    Science.gov (United States)

    Venner, Sandra H.; Sullivan, Ashley F.; Seavey, Dorie

    America today is haunted by the paradox of hunger and food insecurity amidst unprecedented prosperity. Despite a record economic expansion, millions of American households struggle to find sufficient resources to feed family members. Focusing on families with children, this report presents current evidence on hunger and food insecurity, identifies…

  18. Strategic brand management: Archetypes for managing brands through paradoxes

    OpenAIRE

    Högström, Claes; Gustafsson, ,Anders; Tronvoll, Bård

    2015-01-01

    Although brands are acknowledged as significant assets in a firm's value creation and differentiation process, branding literature often describes opposing perspectives and contradictory demands. This article develops a framework of three strategic brand management archetypes that provide new insights into the complexity and often paradoxical ambiguity of branding. By combining an empirical qualitative study with extant brand management and relational exchange theory, the authors ...

  19. Humanizing the Humanities: Some Reflections on George Steiner's "Brutal Paradox."

    Science.gov (United States)

    Karier, Clarence J.

    1990-01-01

    Considers how literary critic, George Steiner, explores the failure of Western Civilization to humanize humanity. Analyzes Steiner's ultimately elitist model of culture to shed light on implications of his brutal paradox in which Nazism's death camps are juxtaposed to high culture. Theorizes about the possibilities of a culture inclusive of all…

  20. Time symmetry and interpretation of quantum mechanics. [Paradoxes

    Energy Technology Data Exchange (ETDEWEB)

    de Beauregard, O.C.

    1976-10-01

    A drastic resolution of the quantum paradoxes is proposed, combining (I) von Neumann's postulate that collapse of the state vector is due to the act of observation, and (II) my reinterpretation of von Neumann's quantal irreversibility as an equivalence between wave retardation and entropy increase, both being ''factlike'' rather than ''lawlike'' (Mehlberg). This entails a coupling of the two de jure symmetries between (I) retarded and (II) advanced waves, and between Aristotle's information as (I) learning and (II) willing awareness. Symmetric acceptance of cognizance as a source of retarded waves, and of will as a sink of advanced waves, is submitted as a central ''paradox'' of the Copernican or Einsteinian sort, out of which new light is shed upon previously known paradoxes, such as the EPR paradox, Schroedinger's cat, and Wigner's friend. Parapsychology is thus found to creep into the picture.