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Sample records for double edged sword

  1. Immune mechanism: a 'double-edged sword'.

    PubMed

    Musa, Mustaffa

    2013-05-01

    Immunology has now developed into an independent discipline in medicine which covers not only germ infection which is related to immunity solely but also covers a lot of non-infectious diseases such as autoimmune disease, allergies, and others. Therefore, "The Immune Mechanism: "A Double-Edged Sword" means that the immune mechanism (consisted of antibody mediated mechanism and T cell mediated mechanism), just like one edge playing the role of giving benefit (immunity) as it destroys the agent of infection, and another one can be detrimental as it will cause tissue/cell damages and then give rise to immune diseases (immunopathology). Now, the prevalence of these immune diseases is on the rise and has become a new challenge to our country towards developed country in 2020. Therefore, we have to make ample preparation (laboratory facilities/services, main power, and research) from now on in order to face the problems and challenges.

  2. Nodulation outer proteins: double-edged swords of symbiotic rhizobia.

    PubMed

    Staehelin, Christian; Krishnan, Hari B

    2015-09-15

    Rhizobia are nitrogen-fixing bacteria that establish a nodule symbiosis with legumes. Nodule formation depends on signals and surface determinants produced by both symbiotic partners. Among them, rhizobial Nops (nodulation outer proteins) play a crucial symbiotic role in many strain-host combinations. Nops are defined as proteins secreted via a rhizobial T3SS (type III secretion system). Functional T3SSs have been characterized in many rhizobial strains. Nops have been identified using various genetic, biochemical, proteomic, genomic and experimental approaches. Certain Nops represent extracellular components of the T3SS, which are visible in electron micrographs as bacterial surface appendages called T3 (type III) pili. Other Nops are T3 effector proteins that can be translocated into plant cells. Rhizobial T3 effectors manipulate cellular processes in host cells to suppress plant defence responses against rhizobia and to promote symbiosis-related processes. Accordingly, mutant strains deficient in synthesis or secretion of T3 effectors show reduced symbiotic properties on certain host plants. On the other hand, direct or indirect recognition of T3 effectors by plant cells expressing specific R (resistance) proteins can result in effector triggered defence responses that negatively affect rhizobial infection. Hence Nops are double-edged swords that may promote establishment of symbiosis with one legume (symbiotic factors) and impair symbiotic processes when bacteria are inoculated on another legume species (asymbiotic factors). In the present review, we provide an overview of our current understanding of Nops. We summarize their symbiotic effects, their biochemical properties and their possible modes of action. Finally, we discuss future perspectives in the field of T3 effector research. © 2015 Authors; published by Portland Press Limited.

  3. Education Is a Double-Edged Sword: Thoughts on Indian and Non-Indian Education.

    ERIC Educational Resources Information Center

    Simonelli, Richard

    2001-01-01

    For Native people and others who feel the dangers of the dominant materialistic world view, education is a double-edged sword. Mainstream education and the skills it teaches are necessary to survive in contemporary life, but mainstream values may be destructive to humanity and must be balanced by learning activities that promote heart,…

  4. 14-3-3σ, the double-edged sword of human cancers

    PubMed Central

    Li, Zhaomin; Liu, Jing-Yuan; Zhang, Jian-Ting

    2009-01-01

    14-3-3σ is a member of a highly conserved family of 14-3-3 proteins that are present in all eukaryotic organisms. 14-3-3σ has been considered as a tumor suppressor with reduced expression in some human cancers while its increased expression causes resistance to anticancer agents and radiation that cause DNA damages. The increased expression of 14-3-3σ may also predict poor prognosis in some human cancers. Thus, 14-3-3σ may play an important role as a double-edged sword in human cancers, which may attribute to its property as a molecular chaperone by binding to various protein ligands important to many cellular processes such as cell cycle checkpoint regulation and apoptosis in response to DNA damages. In this article, we will review recent studies and progresses in understanding 14-3-3σ as a double-edged sword in human cancers. PMID:19956445

  5. Exogenous antioxidants—Double-edged swords in cellular redox state

    PubMed Central

    Bohn, Torsten

    2010-01-01

    The balance between oxidation and antioxidation is believed to be critical in maintaining healthy biological systems. Under physiological conditions, the human antioxidative defense system including e.g., superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione (GSH) and others, allows the elimination of excess reactive oxygen species (ROS) including, among others superoxide anions (O2.-), hydroxyl radicals (OH.), alkoxyl radicals (RO.) and peroxyradicals (ROO.). However, our endogenous antioxidant defense systems are incomplete without exogenous originating reducing compounds such as vitamin C, vitamin E, carotenoids and polyphenols, playing an essential role in many antioxidant mechanisms in living organisms. Therefore, there is continuous demand for exogenous antioxidants in order to prevent oxidative stress, representing a disequilibrium redox state in favor of oxidation. However, high doses of isolated compounds may be toxic, owing to prooxidative effects at high concentrations or their potential to react with beneficial concentrations of ROS normally present at physiological conditions that are required for optimal cellular functioning. This review aims to examine the double-edged effects of dietary originating antioxidants with a focus on the most abundant compounds, especially polyphenols, vitamin C, vitamin E and carotenoids. Different approaches to enrich our body with exogenous antioxidants such as via synthetic antioxidants, diets rich in fruits and vegetables and taking supplements will be reviewed and experimental and epidemiological evidences discussed, highlighting that antioxidants at physiological doses are generally safe, exhibiting interesting health beneficial effects. PMID:20972369

  6. Swords with Blunt Edges

    ERIC Educational Resources Information Center

    Popham, W. James

    2004-01-01

    Many U.S. educators now wonder whether they're teachers or targets. This mentality stems from the specter of their school being sanctioned for failing the state accountability tests mandated under No Child Left Behind (NCLB). According to this author, most of those tests are like blunt-edged swords: They function badly in two directions. While…

  7. Economic empowerment and AIDS-related stigma in rural Kenya: a double-edged sword?

    PubMed

    Gnauck, Katherine; Ruiz, Jamie; Kellett, Nicole; Sussman, Andrew; Sullivan, Mary Ann; Montoya, Maria; Levin, Nick; Tomedi, Angelo; Mwanthi, Mutuku A

    2013-01-01

    Economic empowerment, HIV risk and AIDS-related stigma appear intricately intertwined for women in Kenya. Their interaction must be understood in order to implement effective economic interventions that also decrease HIV risk and stigma. We conducted a qualitative study amongst women in a rural Kamba-speaking community of southeastern Kenya to pursue whether engagement in an economic empowerment initiative (a basket weaving cooperative) influences women's perspectives and experiences with HIV risk and AIDS-related stigma. We conducted seven women's focus groups: participants in the local basket-weaving cooperative comprised four focus groups and non-participants comprised the remaining three groups. The HIV status of the women was not known. Three dominant themes emerged from the focus groups: empowerment, pervasive vulnerability and unanticipated social paradoxes. Contradictions found in these themes suggest that economic empowerment can become a double-edged sword. Economic empowerment enhanced perceived individual, domestic and social community status. However, this enhancement was not protective of domestic violence and perceived HIV risk. Social perceptions may have paradoxically contributed barriers to HIV testing and treatment putting women at greater HIV risk. In conclusion, economic empowerment initiatives for women in developing countries in the context of the HIV epidemic should be coupled with peer mediated support and HIV-risk education.

  8. Role of Cytokines as a Double-edged Sword in Sepsis

    PubMed Central

    CHAUDHRY, HINA; ZHOU, JUHUA; ZHONG, YIN; ALI, MIR MUSTAFA; MCGUIRE, FRANKLIN; NAGARKATTI, PRAKASH S.; NAGARKATTI, MITZI

    2014-01-01

    Background Sepsis is a deadly immunological disorder and its pathophysiology is still poorly understood. We aimed to determine if specific pro-inflammatory and anti-inflammatory cytokines can be used as diagnostic and therapeutic targets for sepsis. Materials and Methods Recent publications in the MEDLINE database were searched for articles regarding the clinical significance of inflammatory cytokines in sepsis. Results In response to pathogen infection, pro-inflammatory cytokines [interleukin-6 (IL-6), IL-8, IL-18 and tumor necrosis factor-α (TNF-α)] and anti-inflammatory cytokine (IL-10) increased in patients with sepsis. Importantly, a decrease in IL-6 was associated with a better prognosis and overproduction of IL-10 was found to be the main predictor of severity and fatal outcome. Conclusion Both pro-inflammatory and anti-inflammatory cytokines constitute a double-edged sword in sepsis; on one hand they are critical to eliminate the infection while on the other, excessive production can cause tissue and organ damage. Increase in cytokines such as IL-6, Il-8, IL-10, IL-18 and TNF-α may have implications in diagnosis and treatment of sepsis. PMID:24292568

  9. Peer pressure is a double-edged sword in vaccination dynamics

    NASA Astrophysics Data System (ADS)

    Wu, Zhi-Xi; Zhang, Hai-Feng

    2013-10-01

    Whether or not to change behavior depends not only on the personal success of each individual, but also on the success and/or behavior of others. Using this as motivation, we incorporate the impact of peer pressure into a susceptible-vaccinated-infected-recovered (SVIR) epidemiological model, where the propensity to adopt a particular vaccination strategy depends both on individual success as well as on the strategies of neighbors. We show that plugging into the peer pressure is a double-edged sword, which, on the one hand, strongly promotes vaccination when its cost is below a critical value, but, on the other hand, it can also strongly impede it if the critical value is exceeded. We explain this by revealing a facilitated cluster formation process that is induced by the peer pressure. Due to this, the vaccinated individuals are inclined to cluster together and therefore become unable to efficiently inhibit the spread of the infectious disease if the vaccination is costly. If vaccination is cheap, however, they reinforce each other in using it. Our results are robust to variations of the SVIR dynamics on different population structures.

  10. Education and income: double-edged swords in the epidemiologic transition of cardiovascular disease.

    PubMed

    Pearson, Thomas A

    2003-01-01

    The 2002 World Health Report warns that the allies of poverty and ignorance are joining forces with the new formidable enemies of health. This describes the epidemiologic transition of burden of disease from infectious and parasitic diseases to that of noncommunicable diseases. All parts of the world, with the possible exception of sub-Saharan Africa, have well-established epidemics of coronary heart disease and stroke. Hypertension contributes significantly to mortality everywhere and is a leading global problem. Education and wealth have strong influences on the epidemiologic transition and might serve as a double-edged sword of benefit and risk. While improved education and enhanced resources are necessary to reduce infectious, parasitic, and perinatal diseases, these factors are also associated with adoption of deleterious health behaviors, which lead to the atherosclerotic diseases. The diffusion of innovation theory describes the early adoption of unhealthy lifestyles in the educated and wealthy, who soon recognize the costs to their community and modify these lifestyles. The uneducated poor may adopt these unhealthy lifestyles later, but, once that occurs, are left with higher risk and burden of cardiovascular disease. One possible reason for this is that discretionary income and the desire for modern conveniences quickly attract unhealthy products (tobacco, high fat/high salt foods) and unhealthy behaviors (sedentary entertainment transportation without physical exertion). The commercial interests of these products have been efficient and effective in delivering their messages to developing societies. Heart health organizations must be more aggressive in their assessment of needs for programs, education of people over a broad range of education levels, assurance of access to heart health services, alteration of the environment to facilitate heart health, and the development of policies and laws to limit deleterious products and behaviors. These late

  11. Breaking the Double-Edged Sword of Effort/Trying Hard: Developmental Equilibrium and Longitudinal Relations among Effort, Achievement, and Academic Self-Concept

    ERIC Educational Resources Information Center

    Marsh, Herbert W.; Pekrun, Reinhard; Lichtenfeld, Stephanie; Guo, Jiesi; Arens, A. Katrin; Murayama, Kou

    2016-01-01

    Ever since the classic research of Nicholls (1976) and others, effort has been recognized as a double-edged sword: while it might enhance achievement, it undermines academic self-concept (ASC). However, there has not been a thorough evaluation of the longitudinal reciprocal effects of effort, ASC, and achievement, in the context of modern…

  12. Breaking the Double-Edged Sword of Effort/Trying Hard: Developmental Equilibrium and Longitudinal Relations among Effort, Achievement, and Academic Self-Concept

    ERIC Educational Resources Information Center

    Marsh, Herbert W.; Pekrun, Reinhard; Lichtenfeld, Stephanie; Guo, Jiesi; Arens, A. Katrin; Murayama, Kou

    2016-01-01

    Ever since the classic research of Nicholls (1976) and others, effort has been recognized as a double-edged sword: while it might enhance achievement, it undermines academic self-concept (ASC). However, there has not been a thorough evaluation of the longitudinal reciprocal effects of effort, ASC, and achievement, in the context of modern…

  13. Facebook and its effects on users' empathic social skills and life satisfaction: a double-edged sword effect.

    PubMed

    Chan, Terri H

    2014-05-01

    This study examines how Facebook usage affects individual's empathic social skills and life satisfaction. Following the self-presentational theory, the study explores a key component of the Internet paradox-whether Facebook suppresses or enhances users' interpersonal competence (specifically empathic social skills), given their respective personality makeup. Going further, the study assesses these events' subsequent impacts on users' psychological well-being. Analogous to a double-edged sword, Facebook activities are hypothesized to suppress the positive effect of a user's extraversion orientation on empathic social skills but lessen the negative effect of neuroticism on these skills. The study examines a sample of college-aged Facebook users (n=515), who responded to a large-scale online survey. The findings from a structural equation modeling analysis indicate that while empathic social skills are positively associated with life satisfaction, Facebook activities mainly exert suppression effects. Only upon low usage can Facebook activities lessen the negative effect of neuroticism on empathic social skills, suggesting that Facebook may appear as a less threatening platform for social interactions among neurotics. Yet, results in general suggest that undesirable effects may occur at high levels of Facebook usage whereby both extroverted and neurotic users displace real world social ties to online ones. The findings point to the complex ways in which social media usage may impact the livelihood of users.

  14. Galectins: Double-edged Swords in the Cross-roads of Pregnancy Complications and Female Reproductive Tract Inflammation and Neoplasia

    PubMed Central

    Than, Nandor Gabor; Romero, Roberto; Balogh, Andrea; Karpati, Eva; Mastrolia, Salvatore Andrea; Staretz-Chacham, Orna; Hahn, Sinuhe; Erez, Offer; Papp, Zoltan; Kim, Chong Jai

    2015-01-01

    Galectins are an evolutionarily ancient and widely expressed family of lectins that have unique glycan-binding characteristics. They are pleiotropic regulators of key biological processes, such as cell growth, proliferation, differentiation, apoptosis, signal transduction, and pre-mRNA splicing, as well as homo- and heterotypic cell-cell and cell-extracellular matrix interactions. Galectins are also pivotal in immune responses since they regulate host-pathogen interactions, innate and adaptive immune responses, acute and chronic inflammation, and immune tolerance. Some galectins are also central to the regulation of angiogenesis, cell migration and invasion. Expression and functional data provide convincing evidence that, due to these functions, galectins play key roles in shared and unique pathways of normal embryonic and placental development as well as oncodevelopmental processes in tumorigenesis. Therefore, galectins may sometimes act as double-edged swords since they have beneficial but also harmful effects for the organism. Recent advances facilitate the use of galectins as biomarkers in obstetrical syndromes and in various malignancies, and their therapeutic applications are also under investigation. This review provides a general overview of galectins and a focused review of this lectin subfamily in the context of inflammation, infection and tumors of the female reproductive tract as well as in normal pregnancies and those complicated by the great obstetrical syndromes. PMID:26018511

  15. Interleukin-22 Might Act as a Double-Edged Sword in Type 2 Diabetes and Coronary Artery Disease

    PubMed Central

    Wu, Jin; Zhou, Ping; Zhang, Mengyao; Liu, Jingning; Liu, Ying

    2016-01-01

    Type 2 diabetes mellitus (T2DM) and coronary artery disease (CAD) are both characterized by chronic low-grade inflammation. The role of Th17 and its related cytokines in T2DM and CAD is unclear. Here we investigated the serum levels of five Th17-related cytokines (IL-17, IL-22, MIP-3α, IL-9, and IL-27) in T2DM, CAD, and T2DM-CAD comorbidity patients. IL-22 was found to be elevated in all three conditions. Elevated serum IL-22 was independently associated with the incidence of T2DM and CAD. Conversely, IL-22 was found to protect endothelial cells from glucose- and lysophosphatidylcholine- (LPC-) induced injury, and IL-22R1 expression on endothelial cells was increased upon treatment with high glucose and LPC. Blocking of IL-22R1 with IL-22R1 antibody diminished the protective role of IL-22. Our results suggest that IL-22 functions as a double-edged sword in T2DM and CAD and that IL-22 may be used in the treatment of chronic inflammatory diseases such as T2DM and CAD. PMID:27829708

  16. The double-edged sword of grandiose narcissism: implications for successful and unsuccessful leadership among U.S. Presidents.

    PubMed

    Watts, Ashley L; Lilienfeld, Scott O; Smith, Sarah Francis; Miller, Joshua D; Campbell, W Keith; Waldman, Irwin D; Rubenzer, Steven J; Faschingbauer, Thomas J

    2013-12-01

    Recent research and theorizing suggest that narcissism may predict both positive and negative leadership behaviors. We tested this hypothesis with data on the 42 U.S. presidents up to and including George W. Bush, using (a) expert-derived narcissism estimates, (b) independent historical surveys of presidential performance, and (c) largely or entirely objective indicators of presidential performance. Grandiose, but not vulnerable, narcissism was associated with superior overall greatness in an aggregate poll; it was also positively associated with public persuasiveness, crisis management, agenda setting, and allied behaviors, and with several objective indicators of performance, such as winning the popular vote and initiating legislation. Nevertheless, grandiose narcissism was also associated with several negative outcomes, including congressional impeachment resolutions and unethical behaviors. We found that presidents exhibit elevated levels of grandiose narcissism compared with the general population, and that presidents' grandiose narcissism has been rising over time. Our findings suggest that grandiose narcissism may be a double-edged sword in the leadership domain.

  17. A double-edged sword? Health research and research governance in UK primary care.

    PubMed

    Shaw, Sara E; Petchey, Roland P; Chapman, Jenifer; Abbott, Stephen

    2009-03-01

    Contemporary health research is becoming increasingly formalised, regulated and institutionalised. In the UK, this has manifested itself in the development of a framework for 'governing' health research. The framework is often presented as a neutral decision-making tool guiding elements of research (such as ethical and peer review) through formal governance processes and approval procedures. We locate the framework as emerging in the wider context of the growth of 'guidelines' in healthcare that raises questions about the extent to which formal rationality has taken hold on knowledge production and what this means for health research. We therefore explore if and how the framework prioritises particular approaches to the production of knowledge and the tensions that emerge between managerial requirements and the work of researchers. We employed qualitative telephone interviews to access the accounts of both researchers and administrators across a range of primary healthcare settings in England and to capture a range of experiences and levels of involvement in research and governance. Our analysis revealed the double-edged nature of research governance: on the one hand, the framework provided a valuable aid to decision-making and the formalisation of tacit knowledge about 'good research practice'; on the other, consequent managerial processes engaged researchers in a series of low-level activities and privileged particular ways of viewing the world. Our findings add to existing knowledge by moving beyond documenting concerns over research governance and show how the reduction of research governance according to a 'common' set of principles and procedures facilitates the production (and managerial oversight) of quantitative and clinical, over qualitative and experiential, knowledge.

  18. Medical ideology as a double-edged sword: the politics of cure and care in the making of Alzheimer's disease.

    PubMed

    Chaufan, Claudia; Hollister, Brooke; Nazareno, Jennifer; Fox, Patrick

    2012-03-01

    This paper builds on our prior work concerning the emergence of Alzheimer's disease (AD) as a major social and health concern. Our study was conducted in two phases (1985-1987 and 2009-2011). We examined the historical evolution of the concept of AD and the emergence of the AD social movement in the U. S. Sources include interviews with movement leaders and scientists, historical documents of the Alzheimer's Association, Congressional records, and published literature. We identified recurrent themes and salient issues motivating those in the movement, its barriers and facilitators, and the roles of government and NGOs in the creation of an organizational structure to maintain it. The characterization of AD as a leading cause of death among the elderly was crucial to sustaining the movement, but also operated as a "double edged sword". By construing "senility" as a treatable, even curable biomedical entity, the movement substantively contributed to the notion of an impending "crisis" of the aging population to be avoided at all costs, compounding the effect of conservative federal policies that emphasized the treatment or cure of AD, and less so the long-term care service needs of sufferers and caregivers that had given rise to the movement. We also discuss how the continuing hegemony of the medical model establishes a race against the demographic clock, pitting advances in biomedical research against the needs of an aging population. We propose that alternative framings and sources of legitimization are critical to address the needs and preserve the humanity of people living with AD and their caregivers.

  19. NR2B subunit in the prefrontal cortex: A double-edged sword for working memory function and psychiatric disorders

    PubMed Central

    Monaco, Sarah A.; Gulchina, Yelena; Gao, Wen-Jun

    2015-01-01

    The prefrontal cortex (PFC) is a brain region featured with working memory function. The exact mechanism of how working memory operates within the PFC circuitry is unknown, but persistent neuronal firing recorded from prefrontal neurons during a working memory task is proposed to be the neural correlate of this mnemonic encoding. The PFC appears to be specialized for sustaining persistent firing, with N-methyl-D-aspartate (NMDA) receptors, especially slow-decay NR2B subunits, playing an essential role in the maintenance of sustained activity and normal working memory function. However, the NR2B subunit serves as a double-edged sword for PFC function. Because of its slow kinetics, NR2B endows the PFC with not only “neural psychic” properties, but also susceptibilities for neuroexcitotoxicity and psychiatric disorders. This review aims to clarify the interplay among working memory, the PFC, and NMDA receptors; demonstrate the importance of the NR2B subunit in the maintenance of persistent activity; understand the risks and vulnerabilities of how NR2B is related to the development of neuropsychiatric disorders; identify gaps that currently exist in our understanding of these processes; and provide insights regarding future directions that may clarify these issues. We conclude that the PFC is a specialized brain region with distinct delayed maturation, unique neuronal circuitry, and characteristic NMDA receptor function. The unique properties and development of NMDA receptors, especially enrichment of NR2B subunits, endows the PFC with not only the capability to generate sustained activity for working memory, but also serves as a major vulnerability to environmental insults and risk factors for psychiatric disorders. PMID:26143512

  20. Comparative phylogeography highlights the double-edged sword of climate change faced by arctic- and alpine-adapted mammals.

    PubMed

    Lanier, Hayley C; Gunderson, Aren M; Weksler, Marcelo; Fedorov, Vadim B; Olson, Link E

    2015-01-01

    Recent studies suggest that alpine and arctic organisms may have distinctly different phylogeographic histories from temperate or tropical taxa, with recent range contraction into interglacial refugia as opposed to post-glacial expansion out of refugia. We use a combination of phylogeographic inference, demographic reconstructions, and hierarchical Approximate Bayesian Computation to test for phylodemographic concordance among five species of alpine-adapted small mammals in eastern Beringia. These species (Collared Pikas, Hoary Marmots, Brown Lemmings, Arctic Ground Squirrels, and Singing Voles) vary in specificity to alpine and boreal-tundra habitat but share commonalities (e.g., cold tolerance and nunatak survival) that might result in concordant responses to Pleistocene glaciations. All five species contain a similar phylogeographic disjunction separating eastern and Beringian lineages, which we show to be the result of simultaneous divergence. Genetic diversity is similar within each haplogroup for each species, and there is no support for a post-Pleistocene population expansion in eastern lineages relative to those from Beringia. Bayesian skyline plots for four of the five species do not support Pleistocene population contraction. Brown Lemmings show evidence of late Quaternary demographic expansion without subsequent population decline. The Wrangell-St. Elias region of eastern Alaska appears to be an important zone of recent secondary contact for nearctic alpine mammals. Despite differences in natural history and ecology, similar phylogeographic histories are supported for all species, suggesting that these, and likely other, alpine- and arctic-adapted taxa are already experiencing population and/or range declines that are likely to synergistically accelerate in the face of rapid climate change. Climate change may therefore be acting as a double-edged sword that erodes genetic diversity within populations but promotes divergence and the generation of

  1. Comparative Phylogeography Highlights the Double-Edged Sword of Climate Change Faced by Arctic- and Alpine-Adapted Mammals

    PubMed Central

    Lanier, Hayley C.; Gunderson, Aren M.; Weksler, Marcelo; Fedorov, Vadim B.; Olson, Link E.

    2015-01-01

    Recent studies suggest that alpine and arctic organisms may have distinctly different phylogeographic histories from temperate or tropical taxa, with recent range contraction into interglacial refugia as opposed to post-glacial expansion out of refugia. We use a combination of phylogeographic inference, demographic reconstructions, and hierarchical Approximate Bayesian Computation to test for phylodemographic concordance among five species of alpine-adapted small mammals in eastern Beringia. These species (Collared Pikas, Hoary Marmots, Brown Lemmings, Arctic Ground Squirrels, and Singing Voles) vary in specificity to alpine and boreal-tundra habitat but share commonalities (e.g., cold tolerance and nunatak survival) that might result in concordant responses to Pleistocene glaciations. All five species contain a similar phylogeographic disjunction separating eastern and Beringian lineages, which we show to be the result of simultaneous divergence. Genetic diversity is similar within each haplogroup for each species, and there is no support for a post-Pleistocene population expansion in eastern lineages relative to those from Beringia. Bayesian skyline plots for four of the five species do not support Pleistocene population contraction. Brown Lemmings show evidence of late Quaternary demographic expansion without subsequent population decline. The Wrangell-St. Elias region of eastern Alaska appears to be an important zone of recent secondary contact for nearctic alpine mammals. Despite differences in natural history and ecology, similar phylogeographic histories are supported for all species, suggesting that these, and likely other, alpine- and arctic-adapted taxa are already experiencing population and/or range declines that are likely to synergistically accelerate in the face of rapid climate change. Climate change may therefore be acting as a double-edged sword that erodes genetic diversity within populations but promotes divergence and the generation of

  2. Combining the Antipsychotic Drug Haloperidol and Environmental Enrichment after Traumatic Brain Injury Is a Double-Edged Sword.

    PubMed

    Folweiler, Kaitlin A; Bondi, Corina O; Ogunsanya, Elizabeth A; LaPorte, Megan J; Leary, Jacob B; Radabaugh, Hannah L; Monaco, Christina M; Kline, Anthony E

    2017-01-15

    Environmental enrichment (EE) confers significant benefits after experimental traumatic brain injury (TBI). In contrast, the antipsychotic drug (APD) haloperidol (HAL) exerts deleterious effects on neurobehavioral and cognitive recovery. Neurorehabilitation and management of agitation, however, are integral components of the treatment strategy for patients with TBI. Hence, the goal of this study was to determine how the two therapeutic approaches interact and influence motor and cognitive recovery. Anesthetized adult male rats received a controlled cortical impact (2.8 mm tissue deformation at 4 m/sec) or sham injury and then were provided HAL (0.5 mg/kg; intraperitoneally [IP]) or vehicle (VEH; 1 mL/kg; IP) commencing 24 h after surgery and once daily for 19 days while housed in EE or standard (STD) conditions. Beam balance/walk and Morris water maze performance were assessed on post-injury days 1-5 and 14-19, respectively, followed immediately by quantification of cortical lesion volumes. The data revealed both expected and unexpected findings. It was not surprising that the TBI groups receiving EE performed significantly better than those in STD housing and that the TBI + STD + HAL group performed worse than the TBI + STD + VEH group (p < 0.05). What was surprising was that the therapeutic effects of EE were greatly reduced by concomitant administration of HAL. No differences in cortical lesion volumes were observed among the groups (p > 0.05). The potential clinical implications of these findings suggest that administering HAL to patients undergoing neurorehabilitation may be a double-edged sword because agitation must be controlled before rehabilitation can be safely initiated and executed, but its use may compromise therapeutic efficacy.

  3. NR2B subunit in the prefrontal cortex: A double-edged sword for working memory function and psychiatric disorders.

    PubMed

    Monaco, Sarah A; Gulchina, Yelena; Gao, Wen-Jun

    2015-09-01

    The prefrontal cortex (PFC) is a brain region featured with working memory function. The exact mechanism of how working memory operates within the PFC circuitry is unknown, but persistent neuronal firing recorded from prefrontal neurons during a working memory task is proposed to be the neural correlate of this mnemonic encoding. The PFC appears to be specialized for sustaining persistent firing, with N-methyl-D-aspartate (NMDA) receptors, especially slow-decay NR2B subunits, playing an essential role in the maintenance of sustained activity and normal working memory function. However, the NR2B subunit serves as a double-edged sword for PFC function. Because of its slow kinetics, NR2B endows the PFC with not only "neural psychic" properties, but also susceptibilities for neuroexcitotoxicity and psychiatric disorders. This review aims to clarify the interplay among working memory, the PFC, and NMDA receptors; demonstrate the importance of NR2B in the maintenance of persistent activity; understand the risks and vulnerabilities of how NR2B is related to the development of neuropsychiatric disorders; identify gaps that currently exist in our understanding of these processes; and provide insights regarding future directions that may clarify these issues. We conclude that the PFC is a specialized brain region with distinct delayed maturation, unique neuronal circuitry, and characteristic NMDA receptor function. The unique properties and development of NMDA receptors, especially enrichment of NR2B subunits, endow the PFC with not only the capability to generate sustained activity for working memory, but also serves as a major vulnerability to environmental insults and risk factors for psychiatric disorders. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Breaking the double-edged sword of effort/trying hard: Developmental equilibrium and longitudinal relations among effort, achievement, and academic self-concept.

    PubMed

    Marsh, Herbert W; Pekrun, Reinhard; Lichtenfeld, Stephanie; Guo, Jiesi; Arens, A Katrin; Murayama, Kou

    2016-08-01

    Ever since the classic research of Nicholls (1976) and others, effort has been recognized as a double-edged sword: while it might enhance achievement, it undermines academic self-concept (ASC). However, there has not been a thorough evaluation of the longitudinal reciprocal effects of effort, ASC, and achievement, in the context of modern self-concept theory and statistical methodology. Nor have there been developmental equilibrium tests of whether these effects are consistent across the potentially volatile early-to-middle adolescence. Hence, focusing on mathematics, we evaluate reciprocal effects models (REMs) over the first 4 years of secondary school (grades 5-8), relating effort, achievement (test scores and school grades), ASC, and ASC × Effort interactions for a representative sample of 3,144 German students (Mage = 11.75 years at Wave 1). ASC, effort, and achievement were positively correlated at each wave, and there was a clear pattern of positive reciprocal positive effects among ASC, test scores, and school grades-each contributing to the other, after controlling for the prior effects of all others. There was an asymmetrical pattern of effects for effort that is consistent with the double-edged sword premise: prior school grades had positive effects on subsequent effort, but prior effort had nonsignificant or negative effects on subsequent grades and ASC. However, on the basis of a synergistic application of new theory and methodology, we predicted and found a significant ASC × Effort interaction, such that prior effort had more positive effects on subsequent ASC and school grades when prior ASC was high-thus providing a key to breaking the double-edged sword. (PsycINFO Database Record

  5. Autophagy in acute leukemias: a double-edged sword with important therapeutic implications.

    PubMed

    Evangelisti, Cecilia; Evangelisti, Camilla; Chiarini, Francesca; Lonetti, Annalisa; Buontempo, Francesca; Neri, Luca M; McCubrey, James A; Martelli, Alberto M

    2015-01-01

    Macroautophagy, usually referred to as autophagy, is a degradative pathway wherein cytoplasmatic components such as aggregated/misfolded proteins and organelles are engulfed within double-membrane vesicles (autophagosomes) and then delivered to lysosomes for degradation. Autophagy plays an important role in the regulation of numerous physiological functions, including hematopoiesis, through elimination of aggregated/misfolded proteins, and damaged/superfluous organelles. The catabolic products of autophagy (amino acids, fatty acids, nucleotides) are released into the cytosol from autophagolysosomes and recycled into bio-energetic pathways. Therefore, autophagy allows cells to survive starvation and other unfavorable conditions, including hypoxia, heat shock, and microbial pathogens. Nevertheless, depending upon the cell context and functional status, autophagy can also serve as a death mechanism. The cohort of proteins that constitute the autophagy machinery function in a complex, multistep biochemical pathway which has been partially identified over the past decade. Dysregulation of autophagy may contribute to the development of several disorders, including acute leukemias. In this kind of hematologic malignancies, autophagy can either act as a chemo-resistance mechanism or have tumor suppressive functions, depending on the context. Therefore, strategies exploiting autophagy, either for activating or inhibiting it, could find a broad application for innovative treatment of acute leukemias and could significantly contribute to improved clinical outcomes. These aspects are discussed here after a brief introduction to the autophagic molecular machinery and its roles in hematopoiesis. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. DNA Polymerases λ and β: The Double-Edged Swords of DNA Repair

    PubMed Central

    Mentegari, Elisa; Kissova, Miroslava; Bavagnoli, Laura; Maga, Giovanni; Crespan, Emmanuele

    2016-01-01

    DNA is constantly exposed to both endogenous and exogenous damages. More than 10,000 DNA modifications are induced every day in each cell’s genome. Maintenance of the integrity of the genome is accomplished by several DNA repair systems. The core enzymes for these pathways are the DNA polymerases. Out of 17 DNA polymerases present in a mammalian cell, at least 13 are specifically devoted to DNA repair and are often acting in different pathways. DNA polymerases β and λ are involved in base excision repair of modified DNA bases and translesion synthesis past DNA lesions. Polymerase λ also participates in non-homologous end joining of DNA double-strand breaks. However, recent data have revealed that, depending on their relative levels, the cell cycle phase, the ratio between deoxy- and ribo-nucleotide pools and the interaction with particular auxiliary proteins, the repair reactions carried out by these enzymes can be an important source of genetic instability, owing to repair mistakes. This review summarizes the most recent results on the ambivalent properties of these enzymes in limiting or promoting genetic instability in mammalian cells, as well as their potential use as targets for anticancer chemotherapy. PMID:27589807

  7. The HIV/AIDS caregiver identity as a double-edged sword: a discourse analysis on HIV/AIDS caregiving in South Africa.

    PubMed

    Ranjbar, Vania

    2014-09-01

    This article discusses the identity of HIV/AIDS caregivers as constructed by a group of HIV/AIDS caregivers at a non-profit organisation in South Africa. During a 12-month period data were collected through interviews with the organisation's staff and volunteers. Using discourse analysis, the study identified a caregiver identity constructed by participants. This caregiving identity acts as a double-edged sword: while the rewards of caregiving act as a buffer against stressful experiences, the prescriptive nature of the caregiver identity is taxing, and may explain burnout among HIV/AIDS caregivers. The study concludes that for support systems for HIV/AIDS caregivers to be effective, the social culture and identity of HIV/AIDS caregivers must be considered.

  8. A Double-Edged Sword: A Review of Benefits and Risks of Online Nonsuicidal Self-Injury Activities.

    PubMed

    Lewis, Stephen P; Seko, Yukari

    2016-03-01

    This review aimed to synthesize current evidence on the perceived benefits and risks of online activity pertinent to nonsuicidal self-injury (NSSI). A systematic literature search was conducted to identify peer-reviewed articles, which yielded a total of 27 articles published between 2005 and 2015. Following this, a thematic analysis was employed to identify perceived benefits and risks of online NSSI activity. Our thematic analysis identified 4 potential benefits (mitigation of social isolation, recovery encouragement, emotional self-disclosure, curbing NSSI urges) and 3 potential risks (NSSI reinforcement, triggering NSSI urges, stigmatization of NSSI) associated with online NSSI activities. Given the double-edged effect of online NSSI activities, clinicians may benefit from incorporating clients' online NSSI activity in the context of NSSI assessment and treatment. Future research ought to directly examine the link between online NSSI activity and NSSI behavior to better understand the nature of these benefits and risks. © 2015 Wiley Periodicals, Inc.

  9. The Kynurenine Pathway Is a Double-Edged Sword in Immune-Privileged Sites and in Cancer: Implications for Immunotherapy.

    PubMed

    Routy, Jean-Pierre; Routy, Bertrand; Graziani, Gina M; Mehraj, Vikram

    2016-01-01

    The term "immune privilege" was originally coined to describe the suppression of inflammatory responses within organs protected by anatomic barriers, ie, the eyes, brain, placenta, and testes. However, cellular and metabolic processes, which orchestrate immune responses, also control inflammation within these sites. Our current understanding of tolerogenic mechanisms has extended the definition of immune privilege to include hair follicles, the colon, and cancer. By catabolizing tryptophan, cells expressing the enzyme indoleamine-2,3-dioxygenase produce kynurenine metabolites, which orchestrate local and systemic responses to control inflammation, thus maintaining immune privilege. This review highlights the double-edged role played by the kynurenine pathway (KP), which establishes and maintains immune-privileged sites while contributing to cancer immune escape. The identification of the underlying molecular drivers of the KP in immune-privileged sites and in cancer is essential for the development of novel therapies to treat autoimmunity and cancer and to improve transplantation outcomes.

  10. The Kynurenine Pathway Is a Double-Edged Sword in Immune-Privileged Sites and in Cancer: Implications for Immunotherapy

    PubMed Central

    Routy, Jean-Pierre; Routy, Bertrand; Graziani, Gina M.; Mehraj, Vikram

    2016-01-01

    The term “immune privilege” was originally coined to describe the suppression of inflammatory responses within organs protected by anatomic barriers, ie, the eyes, brain, placenta, and testes. However, cellular and metabolic processes, which orchestrate immune responses, also control inflammation within these sites. Our current understanding of tolerogenic mechanisms has extended the definition of immune privilege to include hair follicles, the colon, and cancer. By catabolizing tryptophan, cells expressing the enzyme indoleamine-2,3-dioxygenase produce kynurenine metabolites, which orchestrate local and systemic responses to control inflammation, thus maintaining immune privilege. This review highlights the double-edged role played by the kynurenine pathway (KP), which establishes and maintains immune-privileged sites while contributing to cancer immune escape. The identification of the underlying molecular drivers of the KP in immune-privileged sites and in cancer is essential for the development of novel therapies to treat autoimmunity and cancer and to improve transplantation outcomes. PMID:27773992

  11. The double-edged sword of genetic accounts of criminality: causal attributions from genetic ascriptions affect legal decision making.

    PubMed

    Cheung, Benjamin Y; Heine, Steven J

    2015-12-01

    Much debate exists surrounding the applicability of genetic information in the courtroom, making the psychological processes underlying how people consider this information important to explore. This article addresses how people think about different kinds of causal explanations in legal decision-making contexts. Three studies involving a total of 600 Mechanical Turk and university participants found that genetic, versus environmental, explanations of criminal behavior lead people to view the applicability of various defense claims differently, perceive the perpetrator's mental state differently, and draw different causal attributions. Moreover, mediation and path analyses highlight the double-edged nature of genetic attributions-they simultaneously reduce people's perception of the perpetrator's sense of control while increasing people's tendencies to attribute the cause to internal factors and to expect the perpetrator to reoffend. These countervailing relations, in turn, predict sentencing in opposite directions, although no overall differences in sentencing or ultimate verdicts were found.

  12. The double-edged sword of ovarian cancer information for women at increased risk who have previously taken part in screening

    PubMed Central

    Smits, Stephanie; Boivin, Jacky; Menon, Usha; Brain, Kate

    2016-01-01

    Background Women at increased risk who decide not to have, or to delay, risk-reducing salpingo-oophorectomy have to rely on early diagnosis through symptom awareness and presenting to primary care as soon as possible in the absence of screening. However, little is known about the acceptability to women of this strategy. We aimed to gain an in-depth understanding of women’s perceptions and previous experiences of ovarian cancer symptom management, and the influences on ovarian cancer awareness and anticipated symptom presentation. Method Qualitative interviews were conducted with eight women at increased risk of ovarian cancer who had previously taken part in ovarian cancer screening and analysed using interpretative phenomenological analysis (IPA). Results Familial experience of ovarian cancer and perceived personal risk shaped women’s perceptions and behavioural responses to disease threat. Ovarian cancer information was perceived to be a double-edged sword, regarded as either useful for increasing knowledge and confidence in discussing symptom concerns with health professionals or to be avoided due to fears about cancer. Conclusion Women may be cautious about searching for information independently and in the absence of routine ovarian screening. Practice implications Thought needs to be given to how best to create and disseminate credible ovarian cancer symptom information materials. PMID:27433283

  13. Oxidative Genome Damage and Its Repair in Neurodegenerative Diseases: Function of Transition Metals as a Double-Edged Sword

    PubMed Central

    Hegde, Muralidhar L.; Hegde, Pavana M.; Rao, K.S.J.; Mitra, Sankar

    2013-01-01

    The neurons in the central nervous system (CNS) with high O2 consumption and prolonged life span are chronically exposed to high levels of reactive oxygen species (ROS). Accumulation of ROS-induced genome damage in the form of oxidized bases and single-strand breaks (SSBs) as well as their defective or reduced repair in the brain has been implicated in the etiology of various neurological disorders including Alzheimer’s/Parkinson’s diseases (AD/PD). Although inactivating mutations in some DNA repair genes have been linked to hereditary neurodegenerative diseases, the underlying mechanisms of repair deficiencies for the sporadic diseases is not understood. The ROS-induced DNA damages are predominantly repaired via highly conserved and regulated base excision/SSB repair (BER/SSBR) pathway. We recently made an interesting discovery that transition metals iron (Fe) and copper (Cu) which accumulate excessively in the brains of AD, PD and other neurodegenerative diseases, act as a ‘double-edged sword’ by inducing genotoxic ROS and inhibiting DNA damage repair at the same time. These metals inhibit the base excision activity of NEIL family DNA glycosylases by oxidizing them, changing their structure, and inhibiting their binding to downstream repair proteins. Metal chelators and reducing agents partially reverse the inhibition, while curcumin with both chelating and reducing activities reverses the inhibition nearly completely. In this review, we have discussed the possible etiological linkage of BER/SSBR defects to neurodegenerative diseases and therapeutic potential of metal chelators in restoring DNA repair capacity. PMID:21441656

  14. Risk, Reward, and the Double-Edged Sword: Perspectives on Pharmacogenetic Research and Clinical Testing Among Alaska Native People

    PubMed Central

    Robinson, Renee; Starks, Helene; Burke, Wylie; Dillard, Denise A.

    2013-01-01

    Objectives. Pharmacogenetic research and clinical testing raise important concerns for individuals and communities, especially where past medical research and practice has perpetrated harm and cultivated distrust of health care systems and clinicians. We investigated perceptions of pharmacogenetics among Alaska Native (AN) people. Methods. We held four focus groups for 32 ANs in south central Alaska to elicit views about pharmacogenetics in general and for treatment of cardiovascular disease, breast cancer, depression, and nicotine addiction. We analyzed data for perceived risks and rewards of pharmacogenetics. Results. Potential risks of pharmacogenetics included health care rationing, misuse of information, and stigma to individuals and the AN community. Potential rewards included decreased care costs, improved outcomes, and community development. Participants also discussed 8 contingent conditions that could mitigate risks and increase pharmacogenetic acceptability. Conclusions. Alaska Natives perceive pharmacogenetics as potentially benefitting and harming individuals, communities, and health systems, depending on methods and oversight. Researchers, clinicians, and administrators, especially in community-based clinic and health care systems serving minority populations, must address this “double-edged sword” to effectively conduct pharmacogenetics. PMID:24134351

  15. A novel solid lipid nanoparticle formulation for active targeting to tumor α(v) β(3) integrin receptors reveals cyclic RGD as a double-edged sword.

    PubMed

    Shuhendler, Adam J; Prasad, Preethy; Leung, Michael; Rauth, Andrew M; Dacosta, Ralph S; Wu, Xiao Yu

    2012-09-01

    The overexpression of α(v) β(3) integrin receptors on tumor cells and tumor vascular endothelium makes it a useful target for imaging, chemotherapy and anti-angiogenic therapy. However integrin-targeted delivery of therapeutics by nanoparticles have provided only marginal, if any, enhancement of therapeutic effect. This work was thus focused on the development of novel α(v) β(3) -targeted near infrared light-emitting solid lipid nanoparticles (SLN) through conjugation to the α(v) β(3) integrin-specific ligand cyclic Arg-Gly-Asp (cRGD), and the assessment of the effects of α(v) β(3) targeting on nanoparticle biodistribution. Since our previously developed non-targeted "stealth" SLN showed little hepatic accumulation, unlike most reported liposomes and micelles, they served as a reference for quantifying the effects of cRGD-conjugation on tumor uptake and whole animal biodistribution of SLN. Non-targeted SLN, actively targeted (RGD-SLN) and blocked RGD-SLN were prepared to contain near infrared quantum dots for live animal imaging. They were injected intravenously to nude mice bearing xenograft orthotopic human breast tumors or dorsal window chamber breast tumors. Tumor micropharmacokinetics of various SLN formulations were determined using intravital microscopy, and whole animal biodistribution was followed over time by optical imaging. The active tumor targeting with cRGD was found to be a "double-edged sword": while the specificity of RGD-SLN accumulation in tumor blood vessels and their tumor residence time increased, their distribution in the liver, spleen, and kidneys was significantly greater than the non-targeted SLN, leaving a smaller amount of nanoparticles in the tumor tissue. Nevertheless the enhanced specificity and retention of RGD-SLN in tumor neovasculature could make this novel formulation useful for tumor neovascular-specific therapies and imaging applications. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. A double-edged sword: advantages and disadvantages to the current emphasis on biogenetic causes of child psychopathology.

    PubMed

    Burt, S Alexandra

    2015-02-01

    Research on child psychopathology is a largely biogenetic endeavor these days, at least according to current funding priorities at the National Institutes of Health in the US. This heavy focus on genetic contributions to child psychopathology has some real advantages. Available research has conclusively indicated that child and adolescent mental health problems are partially genetic in origin and, moreover, are related to neural structure and function (as an example, see Plomin et al.). Moreover, these genetic effects may be responsible for some previously reported 'environmental' effects, such that, what appear to be direct environmental risk factors may in fact reflect genetic/familial risks. As one example, Sengupta et al. (this issue) found that maternal smoking during pregnancy was in fact a marker of maternal and paternal psychopathology. Put another way, the association between ADHD and maternal smoking during pregnancy may index a genetic/familial risk for a more severe form of ADHD, rather than a direct effect of uterine exposure to cigarettes. A final, more subtle reason for the current trend towards biogenetic research is that it has the rarely-discussed but all-too-important 'allure of the unknown'. We have only just recently been able to directly explore the biological underpinnings of psychopathology; and as technology advances, so too will the insights gained (presumably). This offers both funding agencies and individual scientists the very real possibility of making a major new discovery - a siren's call for most of us. In sharp contrast, decades of research have explored putatively environmental contributions to child and adolescent psychopathology. New paradigm-shifting discoveries are thus likely to be fewer in number and farther between (if we continue using traditional study designs that omit joint consideration of biology, that is). In short, biogenetic research just feels more cutting edge at the moment. The clear merits of such work

  17. Double-Edge Sword of Sustained ROCK Activation in Prion Diseases through Neuritogenesis Defects and Prion Accumulation.

    PubMed

    Alleaume-Butaux, Aurélie; Nicot, Simon; Pietri, Mathéa; Baudry, Anne; Dakowski, Caroline; Tixador, Philippe; Ardila-Osorio, Hector; Haeberlé, Anne-Marie; Bailly, Yannick; Peyrin, Jean-Michel; Launay, Jean-Marie; Kellermann, Odile; Schneider, Benoit

    2015-08-01

    In prion diseases, synapse dysfunction, axon retraction and loss of neuronal polarity precede neuronal death. The mechanisms driving such polarization defects, however, remain unclear. Here, we examined the contribution of RhoA-associated coiled-coil containing kinases (ROCK), key players in neuritogenesis, to prion diseases. We found that overactivation of ROCK signaling occurred in neuronal stem cells infected by pathogenic prions (PrPSc) and impaired the sprouting of neurites. In reconstructed networks of mature neurons, PrPSc-induced ROCK overactivation provoked synapse disconnection and dendrite/axon degeneration. This overactivation of ROCK also disturbed overall neurotransmitter-associated functions. Importantly, we demonstrated that beyond its impact on neuronal polarity ROCK overactivity favored the production of PrPSc through a ROCK-dependent control of 3-phosphoinositide-dependent kinase 1 (PDK1) activity. In non-infectious conditions, ROCK and PDK1 associated within a complex and ROCK phosphorylated PDK1, conferring basal activity to PDK1. In prion-infected neurons, exacerbated ROCK activity increased the pool of PDK1 molecules physically interacting with and phosphorylated by ROCK. ROCK-induced PDK1 overstimulation then canceled the neuroprotective α-cleavage of normal cellular prion protein PrPC by TACE α-secretase, which physiologically precludes PrPSc production. In prion-infected cells, inhibition of ROCK rescued neurite sprouting, preserved neuronal architecture, restored neuronal functions and reduced the amount of PrPSc. In mice challenged with prions, inhibition of ROCK also lowered brain PrPSc accumulation, reduced motor impairment and extended survival. We conclude that ROCK overactivation exerts a double detrimental effect in prion diseases by altering neuronal polarity and triggering PrPSc accumulation. Eventually ROCK emerges as therapeutic target to combat prion diseases.

  18. Double-Edge Sword of Sustained ROCK Activation in Prion Diseases through Neuritogenesis Defects and Prion Accumulation

    PubMed Central

    Alleaume-Butaux, Aurélie; Nicot, Simon; Pietri, Mathéa; Baudry, Anne; Dakowski, Caroline; Tixador, Philippe; Ardila-Osorio, Hector; Haeberlé, Anne-Marie; Bailly, Yannick; Peyrin, Jean-Michel; Launay, Jean-Marie; Kellermann, Odile; Schneider, Benoit

    2015-01-01

    In prion diseases, synapse dysfunction, axon retraction and loss of neuronal polarity precede neuronal death. The mechanisms driving such polarization defects, however, remain unclear. Here, we examined the contribution of RhoA-associated coiled-coil containing kinases (ROCK), key players in neuritogenesis, to prion diseases. We found that overactivation of ROCK signaling occurred in neuronal stem cells infected by pathogenic prions (PrPSc) and impaired the sprouting of neurites. In reconstructed networks of mature neurons, PrPSc-induced ROCK overactivation provoked synapse disconnection and dendrite/axon degeneration. This overactivation of ROCK also disturbed overall neurotransmitter-associated functions. Importantly, we demonstrated that beyond its impact on neuronal polarity ROCK overactivity favored the production of PrPSc through a ROCK-dependent control of 3-phosphoinositide-dependent kinase 1 (PDK1) activity. In non-infectious conditions, ROCK and PDK1 associated within a complex and ROCK phosphorylated PDK1, conferring basal activity to PDK1. In prion-infected neurons, exacerbated ROCK activity increased the pool of PDK1 molecules physically interacting with and phosphorylated by ROCK. ROCK-induced PDK1 overstimulation then canceled the neuroprotective α-cleavage of normal cellular prion protein PrPC by TACE α-secretase, which physiologically precludes PrPSc production. In prion-infected cells, inhibition of ROCK rescued neurite sprouting, preserved neuronal architecture, restored neuronal functions and reduced the amount of PrPSc. In mice challenged with prions, inhibition of ROCK also lowered brain PrPSc accumulation, reduced motor impairment and extended survival. We conclude that ROCK overactivation exerts a double detrimental effect in prion diseases by altering neuronal polarity and triggering PrPSc accumulation. Eventually ROCK emerges as therapeutic target to combat prion diseases. PMID:26241960

  19. Breaking tolerance in transgenic mice expressing the human TSH receptor A-subunit: thyroiditis, epitope spreading and adjuvant as a 'double edged sword'.

    PubMed

    McLachlan, Sandra M; Aliesky, Holly A; Chen, Chun-Rong; Chong, Gao; Rapoport, Basil

    2012-01-01

    Transgenic mice with the human thyrotropin-receptor (TSHR) A-subunit targeted to the thyroid are tolerant of the transgene. In transgenics that express low A-subunit levels (Lo-expressors), regulatory T cell (Treg) depletion using anti-CD25 before immunization with adenovirus encoding the A-subunit (A-sub-Ad) breaks tolerance, inducing extensive thyroid lymphocytic infiltration, thyroid damage and antibody spreading to other thyroid proteins. In contrast, no thyroiditis develops in Hi-expressor transgenics or wild-type mice. Our present goal was to determine if thyroiditis could be induced in Hi-expressor transgenics using a more potent immunization protocol: Treg depletion, priming with Complete Freund's Adjuvant (CFA) + A-subunit protein and further Treg depletions before two boosts with A-sub-Ad. As controls, anti-CD25 treated Hi- and Lo-expressors and wild-type mice were primed with CFA+ mouse thyroglobulin (Tg) or CFA alone before A-sub-Ad boosting. Thyroiditis developed after CFA+A-subunit protein or Tg and A-sub-Ad boosting in Lo-expressor transgenics but Hi- expressors (and wild-type mice) were resistant to thyroiditis induction. Importantly, in Lo-expressors, thyroiditis was associated with the development of antibodies to the mouse TSHR downstream of the A-subunit. Unexpectedly, we observed that the effect of bacterial products on the immune system is a "double-edged sword". On the one hand, priming with CFA (mycobacteria emulsified in oil) plus A-subunit protein broke tolerance to the A-subunit in Hi-expressor transgenics leading to high TSHR antibody levels. On the other hand, prior treatment with CFA in the absence of A-subunit protein inhibited responses to subsequent immunization with A-sub-Ad. Consequently, adjuvant activity arising in vivo after bacterial infections combined with a protein autoantigen can break self-tolerance but in the absence of the autoantigen, adjuvant activity can inhibit the induction of immunity to autoantigens (like the

  20. ATT- A Double Edged Sword?

    PubMed Central

    Gude, D.; Bansal, D. P.

    2011-01-01

    Antitubercular therapy (ATT) induced hepatotoxicity, although well known to clinicians, is often over looked and underrated. Given the low threshold of starting ATT, especially empirically, the adverse manifestations can take a considerable toll. A variety of associated risk factors compound the morbidity. We throw light on one such a case where ATT was detrimental to the patient and review the literature and possible preventive strategies. PMID:23112401

  1. Graphene toxicity as a double-edged sword of risks and exploitable opportunities: a critical analysis of the most recent trends and developments

    NASA Astrophysics Data System (ADS)

    Volkov, Yuri; McIntyre, Jennifer; Prina-Mello, Adriele

    2017-06-01

    Increased production volumes and a broadening application spectrum of graphene have raised concerns about its potential adverse effects on human health. Numerous reports demonstrate that graphene irrespective of its particular form exerts its effects on a widest range of living organisms, including prokaryotic bacteria and viruses, plants, micro- and macro-invertebrates, mammalian and human cells and whole animals in vivo. However, the available experimental data is frequently a matter of significant divergence and even controversy. Therefore, we provide here a critical analysis of the most recent (2015-2016) reports accumulated in the graphene-related materials biocompatibility and toxicology field in order to elucidate the cutting edge achievements, emerging trends and future opportunities in the area. Experimental findings from the diverse in vitro and in vivo model systems are analysed in the context of the most likely graphene exposure scenarios, such as respiratory inhalation, ingestion route, parenteral administration and topical exposure through the skin. Key factors influencing the toxicity of graphene and its complex derivatives as well as potential risk mitigation approaches exploiting graphene physicochemical properties, surface modifications and possible degradation pathways are also discussed along with its emerging applications for healthcare, diagnostics and innovative therapeutic approaches.

  2. Phenylpropanoids in radioregulation: double edged sword.

    PubMed

    Kim, Wanyeon; Seong, Ki Moon; Youn, BuHyun

    2011-06-30

    Radiotherapy, frequently used for treatment of solid tumors, carries two main obstacles including acquired radioresistance in cancer cells during radiotherapy and normal tissue injury. Phenylpropanoids, which are naturally occurring phytochemicals found in plants, have been identified as potential radiotherapeutic agents due to their anti-cancer activity and relatively safe levels of cytotoxicity. Various studies have proposed that these compounds could not only sensitize cancer cells to radiation resulting in inhibition of growth and cell death but also protect normal cells against radiation-induced damage. This review is intended to provide an overview of recent investigations on the usage of phenylpropanoids in combination with radiotherapy in cancer treatment.

  3. Phenylpropanoids in radioregulation: double edged sword

    PubMed Central

    Kim, Wanyeon; Seong, Ki Moon

    2011-01-01

    Radiotherapy, frequently used for treatment of solid tumors, carries two main obstacles including acquired radioresistance in cancer cells during radiotherapy and normal tissue injury. Phenylpropanoids, which are naturally occurring phytochemicals found in plants, have been identified as potential radiotherapeutic agents due to their anti-cancer activity and relatively safe levels of cytotoxicity. Various studies have proposed that these compounds could not only sensitize cancer cells to radiation resulting in inhibition of growth and cell death but also protect normal cells against radiation-induced damage. This review is intended to provide an overview of recent investigations on the usage of phenylpropanoids in combination with radiotherapy in cancer treatment. PMID:21483230

  4. Chromium genotoxicity: a double-edged sword

    PubMed Central

    Nickens, Kristen P.; Patierno, Steven R.; Ceryak, Susan

    2010-01-01

    Certain forms of hexavalent chromium [Cr(VI)] are known respiratory carcinogens that induce a broad spectrum of DNA damage. Cr(VI)-carcinogenesis may be initiated or promoted through several mechanistic processes including, the intracellular metabolic reduction of Cr(VI) producing chromium species capable of interacting with DNA to yield genotoxic and mutagenic effects, Cr(VI)-induced inflammatory/immunological responses, and alteration of survival signaling pathways. Cr(VI) enters the cell through nonspecific anion channels, and is metabolically reduced by agents including ascorbate, glutathione, and cysteine to Cr(V), Cr(IV), and Cr(III). Cr(III) has a weak membrane permeability capacity and is unable to cross the cell membrane, thereby trapping it within the cell where it can bind to DNA and produce genetic damage leading to genomic instability. Structural genetic lesions produced by the intracellular reduction of Cr(VI) include DNA adducts, DNA strand breaks, DNA-protein crosslinks, oxidized bases, abasic sites, and DNA inter- and intrastrand crosslinks. The damage induced by Cr(VI) can lead to dysfunctional DNA replication and transcription, aberrant cell cycle checkpoints, dysregulated DNA repair mechanisms, microsatelite instability, inflammatory responses, and the disruption of key regulatory gene networks responsible for the balance of cell survival and cell death, which may all play an important role in Cr(VI) carcinogenesis. Several lines of evidence have indicated that neoplastic progression is a result of consecutive genetic/epigenetic changes that provide cellular survival advantages, and ultimately lead to the conversion of normal human cells to malignant cancer cells. This review is based on studies that provide a glimpse into Cr(VI) carcinogenicity via mechanisms including Cr(VI)-induced death-resistance, the involvement of DNA repair mechanisms in survival after chromium exposure, and the activation of survival signaling cascades in response to Cr(VI) genotoxicity. PMID:20430016

  5. Calcium supplement: humanity's double-edged sword.

    PubMed

    Bunyaratavej, Narong; Buranasinsup, Shutipen

    2011-10-01

    The principle aim of the present study is to investigate the dark side of calcium, pollutions in calcium preparation especially lead (Pb), mercury (Hg) and cadmium (Cd). The collected samples were the different calcium salts in the market and 18 preparations which were classified into 3 groups: Calcium carbonate salts, Chelated calcium and natural-raw calcium. All samples were analyzed for lead, cadmium and mercury by inductively Coupled Plasma Mass Spectrometry (ICP-MS) technique, in house method based on AOAC (2005) 999.10 by ICP-MS. The calcium carbonate and the natural-raw calcium in every sample contained lead at 0.023-0.407 mg/kg of calcium powder. Meanwhile, the natural-raw calcium such as oyster, coral and animal bone showed amount of lead at 0.106-0.384 mg/kg with small amounts of mercury and cadmium. The chelated calcium such as calcium gluconate, calcium lactate and calcium citrate are free of lead.

  6. Double-edged sword called technology

    SciTech Connect

    Weisskopf, V.F.

    1980-04-01

    The growing awareness that technological achievements have shortcomings may be an indication of a maturing society developing higher values. Technology developed in response to specific questions about nature; science from the systematic study of the details of nature. The two became linked as scientific knowlege was applied to technological problems, and this altered the structure of society. The positive benefits of this symbiosis have been a longer and better life for much of the world. The negative sides are material and spiritual pollution. Material pollution can be solved only if nuclear war is avoided. By bringing purpose and meaning to individual lives, a popular control of technology could evolve to humanize the social-industrial structure and eliminate spiritual pollution. (DCK)

  7. Silence: a double-edged sword.

    PubMed

    Bunkers, Sandra Schmidt

    2013-01-01

    The author in this column discusses the concept silence and the contradictions present with silence. Silence can be experienced in the following life patterns: silence as a pattern of surrendering to moments of awakening; silence as a pattern of bearing witness to life story; and, silence as a pattern of betrayal of trust. Each of these patterns is explored with their relevance for nursing.

  8. Characterization of a Messer – The late-Medieval single-edged sword of Central Europe

    SciTech Connect

    Fajfar, Peter; Medved, Jožef; Klančnik, Grega; Lazar, Tomaž; Nečemer, Marijan; Mrvar, Primož

    2013-12-15

    Metallurgical characterization of a sword blade fragments dating from the second half of the 15th century found in central Slovenia was performed in order to determine its chemical composition, microstructure, microhardness, and to obtain insight into the methods of manufacture of a late-medieval Messer sword. As the artefact was broken, examinations were limited to six very small fragments that were allowed to be removed from the cutting edge, core and the back of the blade. Light optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, energy dispersive X-ray fluorescence spectrometry, differential scanning calorimetry, thermodynamics approach and Vickers micro-hardness tests were employed to analyze the microstructure and mechanical properties. The results show that the sword was manufactured from a single wrought iron billet. The surface of the sword was carburized. No evidence of quenching was found. The ferritic microstructure is concentrated in the core, and the pearlitic in the outer layer of the blade. All metal fragments contained non-metallic inclusions that were derived mostly from slag and some from hammer scale. - Highlights: • A metallurgical characterization of a medieval sword blade has been performed. • The carbon content decreased from the surface to the core of the blade. • The dominant microstructure in the outer layer is pearlite and in the core is ferrite. • The presence of lump shaped and elongated non-metallic inclusions was observed. • The sword was manufactured from a single wrought iron billet.

  9. Double-Edged Sword: Social Media Use in the Classroom

    ERIC Educational Resources Information Center

    Chromey, Kelli J.; Duchsherer, Amy; Pruett, Jennifer; Vareberg, Kyle

    2016-01-01

    The purpose of this research is to identify the students' perceptions of social media use in a classroom setting. Knowing students' perceptions of social media can help the instructor build a course that both student and teacher can find effective. Using focus groups this study found a model to determine if social media is an appropriate or…

  10. Hypothalamic inflammation: a double-edged sword to nutritional diseases

    PubMed Central

    Cai, Dongsheng; Liu, Tiewen

    2015-01-01

    The hypothalamus is one of the master regulators of various physiological processes, including energy balance and nutrient metabolism. These regulatory functions are mediated by discrete hypothalamic regions that integrate metabolic sensing with neuroendocrine and neural controls of systemic physiology. Neurons and non-neuronal cells in these hypothalamic regions act supportively to execute metabolic regulations. Under conditions of brain and hypothalamic inflammation, which may result from overnutrition-induced intracellular stresses or disease-associated systemic inflammatory factors, extracellular and intracellular environments of hypothalamic cells are disrupted, leading to central metabolic dysregulations and various diseases. Recent research has begun to elucidate the effects of hypothalamic inflammation in causing diverse components of metabolic syndrome leading to diabetes and cardiovascular disease. These new understandings have provocatively expanded previous knowledge on the cachectic roles of brain inflammatory response in diseases, such as infections and cancers. This review describes the molecular and cellular characteristics of hypothalamic inflammation in metabolic syndrome and related diseases as opposed to cachectic diseases, and also discusses concepts and potential applications of inhibiting central/hypothalamic inflammation to treat nutritional diseases. PMID:22417140

  11. Extracellular DNA and histones: double-edged swords in immunothrombosis.

    PubMed

    Gould, T J; Lysov, Z; Liaw, P C

    2015-06-01

    The existence of extracellular DNA in human plasma, also known as cell-free DNA (cfDNA), was first described in the 1940s. In recent years, there has been a resurgence of interest in the functional significance of cfDNA, particularly in the context of neutrophil extracellular traps (NETs). cfDNA and histones are key components of NETs that aid in the host response to infection and inflammation. However, cfDNA and histones may also exert harmful effects by triggering coagulation, inflammation, and cell death and by impairing fibrinolysis. In this article, we will review the pathologic nature of cfDNA and histones in macrovascular and microvascular thrombosis, including venous thromboembolism, cancer, sepsis, and trauma. We will also discuss the prognostic value of cfDNA and histones in these disease states. Understanding the molecular and cellular pathways regulated by cfDNA and histones may provide novel insights to prevent pathological thrombus formation and vascular occlusion.

  12. China’s Exchange Rate Policy: A Double Edged Sword

    DTIC Science & Technology

    2013-12-01

    Figure 6.  Impacts of RMB Appreciation on Consumption and Production Since 2005...trading partners, China has the ability to impact the U.S. economy through its exchange rate polices. Actions that benefit certain sectors in its...understanding of how the current exchange rate policy impacts the different sectors of the economy is vital to continued growth. It appears to be

  13. Adventure Education and Resilience: The Double-Edged Sword.

    ERIC Educational Resources Information Center

    Neill, James T.; Dias, Katica L.

    2001-01-01

    All 41 young adults who finished a 22-day Australian Outward Bound program showed large positive changes in resilience scores. Perceived social support was strongly related to resilience gains, with ratings of the least supportive group member being the best predictor. Recommendations concerning group process are offered to group leaders.…

  14. Myeloid-derived suppressor cells: a double-edged sword?

    PubMed Central

    Pastuła, Agnieszka; Marcinkiewicz, Janusz

    2011-01-01

    Myeloid-derived suppressor cells are important cell population with an immunoregulatory potential in both adaptive and innate immunity. Their immunosuppressive activity is widely accepted. However, emerging evidence suggests that this heterogeneous cell population can be, under some circumstances, immunostimulatory rather than suppressive. This finding can shed a new light on antitumour immunity which is believed to be impaired in immunosuppressive environments. PMID:21314739

  15. The double-edged sword: Neurotoxicity of chemotherapy.

    PubMed

    Magge, Rajiv S; DeAngelis, Lisa M

    2015-03-01

    The number of available therapies for hematologic malignancies continues to grow at a rapid pace. Unfortunately, many of these treatments carry both central and peripheral nervous system toxicities, potentially limiting a patient's ability to tolerate a full course of treatment. Neurotoxicity with chemotherapy is common and second only to myelosuppression as a reason to limit dosing. This review addresses the neurotoxicity of newly available therapeutic agents including brentuximab vedotin and blinatumomab as well as classic ones such as methotrexate, vinca alkaloids and platinums. Although peripheral neuropathy is common with many drugs, other complications such as seizures and encephalopathy may require more immediate attention. Rapid recognition of adverse neurologic effects may lead to earlier treatment and appropriate adjustment of dosing regimens. In addition, knowledge of common toxicities may help differentiate chemotherapy-related symptoms from actual progression of cancer into the CNS.

  16. Playing with a double-edged sword: Analogies in biochemistry

    NASA Astrophysics Data System (ADS)

    Orgill, Marykay

    Analogy pervades our everyday reasoning. No situation we encounter is exactly like a situation we have encountered previously, and our ability to learn and survive in the world is based on our ability to find similarities between past and present situations and use the knowledge we have gained from past situations to manage current situations. Analogies can be powerful teaching tools because they can make new material intelligible to students by comparing it to material that is already familiar. It is clear, though, that not all analogies are good and that not all good analogies are useful to all students. In this study, I have used textbook analysis, classroom observations, student interviews and instructor interviews to determine the role that analogies play in biochemistry learning. Analogies are an important teaching technique in biochemistry classes, being used more often in both biochemistry classes and textbooks than they are in high school chemistry classes and textbooks. Most biochemistry students like, pay particular attention to, and remember the analogies their instructors provide; and they use these analogies to understand, visualize, and recall information from class. Even though students like and use analogies, they do not understand what analogies are or the mechanism by which they improve learning. For the students, analogies are simply any teaching technique that eases understanding, visualization, or recall. Instructors, on the other hand, have a good understanding of what analogies are and of how they should be presented in class; but they do not use analogies as effectively as they should. They do not plan, explain or identify the limitations of the analogies they use in class. However, regardless of how effectively instructors present analogies in class, this study indicates that, in general, analogies are useful in promoting understanding, visualization, recall, and motivation in biochemistry students at all levels. They would be even more useful if students understood what analogies are and how they can be used to improve understanding of biochemical concepts.

  17. Nodulation outer proteins: double-edged swords of symbiotic rhizobia

    USDA-ARS?s Scientific Manuscript database

    Rhizobia are nitrogen-fixing bacteria that establish a nodule symbiosis with legumes. Nodule formation is the result of a complex bacterial infection process, which depends on signals and surface determinants produced by both symbiotic partners. Among them, rhizobial nodulation outer proteins (Nops)...

  18. Double-Edged Sword: Social Media Use in the Classroom

    ERIC Educational Resources Information Center

    Chromey, Kelli J.; Duchsherer, Amy; Pruett, Jennifer; Vareberg, Kyle

    2016-01-01

    The purpose of this research is to identify the students' perceptions of social media use in a classroom setting. Knowing students' perceptions of social media can help the instructor build a course that both student and teacher can find effective. Using focus groups this study found a model to determine if social media is an appropriate or…

  19. Reactive oxygen species a double-edged sword for mesothelioma.

    PubMed

    Benedetti, Serena; Nuvoli, Barbara; Catalani, Simona; Galati, Rossella

    2015-07-10

    It is well known that oxidative stress can lead to chronic inflammation which, in turn, could mediate most chronic diseases including cancer. Oxidants have been implicated in the activity of crocidolite and amosite, the most powerful types of asbestos associated to the occurrence of mesothelioma. Currently rates of mesothelioma are rising and estimates indicate that the incidence of mesothelioma will peak within the next 10-15 years in the western world, while in Japan the peak is predicted not to occur until 40 years from now. Although the use of asbestos has been banned in many countries around the world, production of and the potentially hazardous exposure to asbestos is still present with locally high incidences of mesothelioma. Today a new man-made material, carbon nanotubes, has arisen as a concern; carbon nanotubes may display 'asbestos-like' pathogenicity with mesothelioma induction potential. Carbon nanotubes resulted in the greatest reactive oxygen species generation. How oxidative stress activates inflammatory pathways leading to the transformation of a normal cell to a tumor cell, to tumor cell survival, proliferation, invasion, angiogenesis, chemoresistance, and radioresistance, is the aim of this review.

  20. Reactive oxygen species a double-edged sword for mesothelioma

    PubMed Central

    Catalani, Simona; Galati, Rossella

    2015-01-01

    It is well known that oxidative stress can lead to chronic inflammation which, in turn, could mediate most chronic diseases including cancer. Oxidants have been implicated in the activity of crocidolite and amosite, the most powerful types of asbestos associated to the occurrence of mesothelioma. Currently rates of mesothelioma are rising and estimates indicate that the incidence of mesothelioma will peak within the next 10–15 years in the western world, while in Japan the peak is predicted not to occur until 40 years from now. Although the use of asbestos has been banned in many countries around the world, production of and the potentially hazardous exposure to asbestos is still present with locally high incidences of mesothelioma. Today a new man-made material, carbon nanotubes, has arisen as a concern; carbon nanotubes may display ‘asbestos-like’ pathogenicity with mesothelioma induction potential. Carbon nanotubes resulted in the greatest reactive oxygen species generation. How oxidative stress activates inflammatory pathways leading to the transformation of a normal cell to a tumor cell, to tumor cell survival, proliferation, invasion, angiogenesis, chemoresistance, and radioresistance, is the aim of this review. PMID:26078352

  1. Fluid Therapy: Double-Edged Sword during Critical Care?

    PubMed

    Benes, Jan; Kirov, Mikhail; Kuzkov, Vsevolod; Lainscak, Mitja; Molnar, Zsolt; Voga, Gorazd; Monnet, Xavier

    2015-01-01

    Fluid therapy is still the mainstay of acute care in patients with shock or cardiovascular compromise. However, our understanding of the critically ill pathophysiology has evolved significantly in recent years. The revelation of the glycocalyx layer and subsequent research has redefined the basics of fluids behavior in the circulation. Using less invasive hemodynamic monitoring tools enables us to assess the cardiovascular function in a dynamic perspective. This allows pinpointing even distinct changes induced by treatment, by postural changes, or by interorgan interactions in real time and enables individualized patient management. Regarding fluids as drugs of any other kind led to the need for precise indication, way of administration, and also assessment of side effects. We possess now the evidence that patient centered outcomes may be altered when incorrect time, dose, or type of fluids are administered. In this review, three major features of fluid therapy are discussed: the prediction of fluid responsiveness, potential harms induced by overzealous fluid administration, and finally the problem of protocol-led treatments and their timing.

  2. Oral direct thrombin inhibition: a double-edged sword?

    PubMed

    Fragasso, Gabriele; Corti, Angelo; Loiacono, Ferdinando; Margonato, Alberto; D'Angelo, Armando

    2015-01-01

    New oral anticoagulants have been shown to be not inferior to vitamin K antagonists in reducing thrombo-embolic events in patients with non-valvular atrial fibrillation and venous thrombo-embolism. However, those among them whichdirectly inhibit thrombin have been associated with greater risk of myocardial infarction. In this article we review the pleiotropic physiological effects of thrombin and their potential link with the observed greater incidence of myocardial infarction during therapy with oral direct thrombin inhibitors. On this basis, we believe that further studies are necessary to clear out doubts on the use of these drugs in the general population and, more specifically, in patients with coronary artery disease. For these reasons, in our opinion at present it may be prudent to especially caution high risk patients initiating therapy with a direct thrombin inhibitor (or those who are already taking it) about this possible risk. For patients with established coronary artery disease an alternative oral anticoagulant may be at present a better choice.

  3. HDAC inhibitors and immunotherapy; a double edged sword?

    PubMed

    Kroesen, Michiel; Gielen, Paul; Brok, Ingrid C; Armandari, Inna; Hoogerbrugge, Peter M; Adema, Gosse J

    2014-08-30

    Epigenetic modifications, like histone acetylation, are essential for regulating gene expression within cells. Cancer cells acquire pathological epigenetic modifications resulting in gene expression patterns that facilitate and sustain tumorigenesis. Epigenetic manipulation therefore is emerging as a novel targeted therapy for cancer. Histone Acetylases (HATs) and Histone Deacetylases (HDACs) regulate histone acetylation and hence gene expression. Histone deacetylase (HDAC) inhibitors are well known to affect cancer cell viability and biology and are already in use for the treatment of cancer patients. Immunotherapy can lead to clinical benefit in selected cancer patients, especially in patients with limited disease after tumor debulking. HDAC inhibitors can potentially synergize with immunotherapy by elimination of tumor cells. The direct effects of HDAC inhibitors on immune cell function, however, remain largely unexplored. Initial data have suggested HDAC inhibitors to be predominantly immunosuppressive, but more recent reports have challenged this view. In this review we will discuss the effects of HDAC inhibitors on tumor cells and different immune cell subsets, synergistic interactions and possible mechanisms. Finally, we will address future challenges and potential application of HDAC inhibitors in immunocombination therapy of cancer.

  4. The Double-edged Sword of Autophagy Modulation in Cancer

    PubMed Central

    White, Eileen; DiPaola, Robert S.

    2009-01-01

    Macroautophagy (autophagy) is a lysosomal degradation pathway for the breakdown of intracellular proteins and organelles. Although, constitutive autophagy is a homeostatic mechanism for intracellular recycling and metabolic regulation, autophagy is also stress responsive where it is important for the removal of damaged proteins and organelles. Autophagy thereby confers stress tolerance, limits damage and sustains viability under adverse conditions. Autophagy is a tumor suppression mechanism yet it enables tumor cell survival in stress. Reconciling how loss of a prosurvival function can promote tumorigenesis, emerging evidence suggests that preservation of cellular fitness by autophagy may be key to tumor suppression. As autophagy is such a fundamental process, establishing how the functional status of autophagy influences tumorigenesis and treatment response is important. This is especially critical as many current cancer therapeutics activate autophagy. Therefore, efforts to understand and modulate the autophagy pathway will provide new approaches to cancer therapy and prevention. PMID:19706824

  5. Adolescent Controversial Status Brokers: A Double-Edged Sword

    ERIC Educational Resources Information Center

    Borowski, Sarah; Zeman, Janice; Carboni, Inga; Gilman, Rich; Thrash, Todd

    2017-01-01

    Using a 3-wave longitudinal, multidimensional approach, this study investigated the influence of social network position and social status on the psychosocial outcomes of 440 youth (45.1% girls; M[subscript age] = 16.1 years; 90.9% Caucasian) over 26 months, focusing on the controversial status classification (i.e., youth who are highly liked and…

  6. Exercise and Arrhythmias: A Double-Edged Sword.

    PubMed

    Manolis, Antonis S; Manolis, Antonis A

    2016-07-01

    Ample evidence indicates that moderate regular exercise is beneficial for both normal individuals and patients with cardiovascular (CV) disease. However, intense and strenuous exercise in individuals with evident or occult underlying CV abnormalities may have adverse effects with provocation and exacerbation of arrhythmias that may lead to life-threatening situations. Both of these aspects of exercise-induced effects are herein reviewed.

  7. Opioids and Viral Infections: A Double-Edged Sword

    PubMed Central

    Tahamtan, Alireza; Tavakoli-Yaraki, Masoumeh; Mokhtari-Azad, Talat; Teymoori-Rad, Majid; Bont, Louis; Shokri, Fazel; Salimi, Vahid

    2016-01-01

    Opioids and their receptors have received remarkable attention because they have the ability to alter immune function, which affects disease progression. In vitro and in vivo findings as well as observations in humans indicate that opioids and their receptors positively or negatively affect viral replication and virus-mediated pathology. The present study reviews recent insights in the role of opioids and their receptors in viral infections and discusses possible therapeutic opportunities. This review supports the emerging concept that opioids and their receptors have both favorable and unfavorable effects on viral disease, depending on the type of virus. Targeting of the opioid system is a potential option for developing effective therapies; however caution is required in relation to the beneficial functions of opioid systems. PMID:27446011

  8. Concrete Instantiations of Mathematics: A Double-Edged Sword

    ERIC Educational Resources Information Center

    Kaminski, Jennifer A.; Sloutsky, Vladimir M.; Heckler, Andrew F.

    2009-01-01

    What factors affect transfer of knowledge is a complex question. In recent research, the authors demonstrated that concreteness of the learning domain is one such factor (Kaminski, Sloutsky, & Heckler, 2008). Even when prompted and given no time delay, participants who learned a concrete instantiation of a mathematical concept failed to…

  9. Biologics and the cardiovascular system: a double-edged sword.

    PubMed

    Roubille, Camille; Martel-Pelletier, Johanne; Haraoui, Boulos; Tardif, Jean-Claude; Pelletier, Jean-Pierre

    2013-01-01

    Patients with chronic inflammatory diseases such as rheumatoid arthritis have a higher risk of cardiovascular diseases and related mortality compared to the general population. This risk is first due to classical cardiovascular risk factors but also due to systemic inflammation which is independently involved, causing accelerated atherosclerosis, myocardial infarction, cerebrovascular disease and heart failure (HF). Pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1 and IL-6 could be major actors on this pathophysiology. Biologics are effective specific treatments in the management of inflammatory rheumatic and systemic diseases. In this review, beneficial and deleterious effects on the heart and vessels of the biologics used in the management of inflammatory arthritis and vasculitides will be discussed, focusing on TNF-alpha, IL-6 and IL-1 blockades, and anti-CD20. Noninflammatory cardiac conditions, such as heart failure, myocardial infarction, and cardiovascular conditions such as atherosclerosis, as well as inflammatory diseases including vasculitides will be discussed.

  10. The "Double-Edged Sword" of the Adult Learning Environment

    ERIC Educational Resources Information Center

    Murray, Sara; Mitchell, Jane

    2013-01-01

    The vocational education and training sector plays a critical role in the provision of educational opportunities for young adults who have left school prior to completing a qualification. Some research has found that a major factor that supports student re-engagement in formal education is the "adult learning environment" that…

  11. Fluid Therapy: Double-Edged Sword during Critical Care?

    PubMed Central

    Benes, Jan; Kirov, Mikhail; Kuzkov, Vsevolod; Lainscak, Mitja; Molnar, Zsolt; Voga, Gorazd; Monnet, Xavier

    2015-01-01

    Fluid therapy is still the mainstay of acute care in patients with shock or cardiovascular compromise. However, our understanding of the critically ill pathophysiology has evolved significantly in recent years. The revelation of the glycocalyx layer and subsequent research has redefined the basics of fluids behavior in the circulation. Using less invasive hemodynamic monitoring tools enables us to assess the cardiovascular function in a dynamic perspective. This allows pinpointing even distinct changes induced by treatment, by postural changes, or by interorgan interactions in real time and enables individualized patient management. Regarding fluids as drugs of any other kind led to the need for precise indication, way of administration, and also assessment of side effects. We possess now the evidence that patient centered outcomes may be altered when incorrect time, dose, or type of fluids are administered. In this review, three major features of fluid therapy are discussed: the prediction of fluid responsiveness, potential harms induced by overzealous fluid administration, and finally the problem of protocol-led treatments and their timing. PMID:26798642

  12. HDAC inhibitors and immunotherapy; a double edged sword?

    PubMed Central

    Kroesen, Michiel; Armandari, Inna; Hoogerbrugge, Peter M.; Adema, Gosse J.

    2014-01-01

    Epigenetic modifications, like histone acetylation, are essential for regulating gene expression within cells. Cancer cells acquire pathological epigenetic modifications resulting in gene expression patterns that facilitate and sustain tumorigenesis. Epigenetic manipulation therefore is emerging as a novel targeted therapy for cancer. Histone Acetylases (HATs) and Histone Deacetylases (HDACs) regulate histone acetylation and hence gene expression. Histone deacetylase (HDAC) inhibitors are well known to affect cancer cell viability and biology and are already in use for the treatment of cancer patients. Immunotherapy can lead to clinical benefit in selected cancer patients, especially in patients with limited disease after tumor debulking. HDAC inhibitors can potentially synergize with immunotherapy by elimination of tumor cells. The direct effects of HDAC inhibitors on immune cell function, however, remain largely unexplored. Initial data have suggested HDAC inhibitors to be predominantly immunosuppressive, but more recent reports have challenged this view. In this review we will discuss the effects of HDAC inhibitors on tumor cells and different immune cell subsets, synergistic interactions and possible mechanisms. Finally, we will address future challenges and potential application of HDAC inhibitors in immunocombination therapy of cancer. PMID:25115382

  13. TRPV1 channels in cardiovascular system: A double edged sword?

    PubMed

    Randhawa, Puneet Kaur; Jaggi, Amteshwar Singh

    2017-02-01

    Apart from modulating nociception, there is vital role of TRPV1 channels in modulating atherosclerosis, congestive heart failure, systemic hypertension, pulmonary hypertension, hemorrhagic shock and vascular remodeling. TRPV1 channel activation has shielding effect against the development of atherosclerosis and systemic hypertension. TRPV1 channel activation alleviates the formation of atherosclerotic lesions via increasing the expression of cholesterol efflux regulatory protein, UCP 2 and enhancing autophagy. Furthermore, activation of these channels enhances Na(+) excretion and NO release to reduce the blood pressure. TRPV1 channel activation in the cardiac sensory neurons and subsequent CGRP release reduces ischemia-reperfusion injury. Activation of these channels during conditioning enhances CGRP and SP release from the sensory nerve fibers innervating the heart to induce cardioprotection. However, activation of these channels may elicit detrimental effects in pulmonary hypertension, hemorrhage and vascular remodeling. Activation of TRPV1 channels enhances smooth muscle cell proliferation to promote pulmonary hypertension. Moreover, TRPV1 channel inhibition reduces massive catecholamine release, improves survival during hemorrhage. Activation of these channels enhances vascular remodeling via enhancing NO release. Furthermore, dual role of TRPV1 channels has been reported in the perpetuation of congestive heart failure. On one hand, TRPV1 channel activation increases the expression of UCP2, PPAR- δ and mitochondrial sirtuin 3 to decrease oxidative stress and reduce heart injury. On the other hand, activation of these channels may enhance the expression of hypertrophic fibrotic proteins viz. GATA4, MMP to promote cardiac fibrosis. The present review discusses the dual role of activation of TRPV1 channels in diseases associated with cardiovascular system.

  14. Autophagy: A Double-Edged Sword to Fight Plant Viruses.

    PubMed

    Clavel, Marion; Michaeli, Simon; Genschik, Pascal

    2017-08-01

    In metazoans, autophagy is an essential component of host defense against viruses, orchestrating their degradation. Such antiviral functions for autophagy have also been long suspected in the green lineage. Two recent reports provide molecular insights on how plants selectively send viral proteins and even particles to the vacuole. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. PTEN degradation after ischemic stroke: a double-edged sword.

    PubMed

    Li, W; Huang, R; Chen, Z; Yan, L-J; Simpkins, J W; Yang, S-H

    2014-08-22

    Tumor suppressor phosphatase and tensin homolog (PTEN) is highly expressed in neurons and PTEN inhibition has been reported to be neuroprotective against ischemic stroke in experimental models. On the other hand, PTEN deletion has been shown to lead to cognitive impairment. In the current study, we examined the expression and functions of PTEN in an ischemic stroke rodent model. We found rapid S-nitrosylation and degradation of PTEN after cerebral ischemia/reperfusion injury. PTEN degradation leads to activation of Akt. PTEN partial deletion or PTEN inhibition increased the expression of GABAA receptor (GABAAR) γ2 subunit and enhanced GABAA receptor current. After cerebral ischemia, increased expression of GABAAR γ2 subunit was observed in the ischemia region and the penumbra area. We also observed PTEN loss in astrocytes after cerebral ischemia. Astrocytic PTEN partial knockout increased astrocyte activation and exacerbated ischemic damage. We speculated that ischemic stroke induced neuronal PTEN degradation, hence enhanced GABAA receptor-medicated neuronal activity inhibition which could attenuate excitotoxicity and provide neuroprotection during the acute phase after stroke, while inhibiting long-term functional recovery and contributing to vascular cognitive impairment after stroke. On the other hand, ischemic stroke induced astrocytic PTEN loss and enhanced ischemic damage and astrogliosis. Taken together, our study indicates that ischemic stroke induces rapid PTEN degradation in both neurons and astrocytes which play both protective and detrimental action in a spatiotemporal- and cell-type-dependent manner. Our study provides critical insight for targeting PTEN signaling pathway for stroke treatment.

  16. Management of impulse control disorders with deep brain stimulation: A double-edged sword.

    PubMed

    Kasemsuk, Chayut; Oyama, Genko; Hattori, Nobutaka

    2017-03-15

    Deep brain stimulation (DBS) is a surgical option for advanced Parkinson's disease. Although DBS is used to treat motor fluctuation, DBS may affect non-motor symptoms including mood disorders, cognitive dysfunction, and behavior problems. Impulse control disorders (ICDs) are abnormal behaviors with various manifestations such as pathological gambling, hypersexuality, compulsive shopping, and binge eating, which can affect the quality of life in patients with Parkinson's disease. The effect of DBS on ICD is controversial. Reducing medication by DBS may improve ICDs, however, worsening or even developing new ICDs after DBS can occur. We will review the impact of DBS on ICDs and reveal factors associated with a good response to DBS as well as risk factors for developing ICDs after DBS. We also propose a strategy to manage preexisting ICD and prevent postoperative de novo ICDs. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. The double-edged sword of pedagogy: Instruction limits spontaneous exploration and discovery.

    PubMed

    Bonawitz, Elizabeth; Shafto, Patrick; Gweon, Hyowon; Goodman, Noah D; Spelke, Elizabeth; Schulz, Laura

    2011-09-01

    Motivated by computational analyses, we look at how teaching affects exploration and discovery. In Experiment 1, we investigated children's exploratory play after an adult pedagogically demonstrated a function of a toy, after an interrupted pedagogical demonstration, after a naïve adult demonstrated the function, and at baseline. Preschoolers in the pedagogical condition focused almost exclusively on the target function; by contrast, children in the other conditions explored broadly. In Experiment 2, we show that children restrict their exploration both after direct instruction to themselves and after overhearing direct instruction given to another child; they do not show this constraint after observing direct instruction given to an adult or after observing a non-pedagogical intentional action. We discuss these findings as the result of rational inductive biases. In pedagogical contexts, a teacher's failure to provide evidence for additional functions provides evidence for their absence; such contexts generalize from child to child (because children are likely to have comparable states of knowledge) but not from adult to child. Thus, pedagogy promotes efficient learning but at a cost: children are less likely to perform potentially irrelevant actions but also less likely to discover novel information.

  18. Teaching Mathematics by Comparison: Analog Visibility as a Double-Edged Sword

    ERIC Educational Resources Information Center

    Begolli, Kreshnik Nasi; Richland, Lindsey Engle

    2016-01-01

    Comparing multiple solutions to a single problem is an important mode for developing flexible mathematical thinking, yet instructionally leading this activity is challenging (Stein, Engle, Smith, & Hughes, 2008). We test 1 decision teachers must make after having students solve a problem: whether to only verbally discuss students' solutions or…

  19. Fear and Attraction in Statecraft: Western Multilateralism’s Double-Edged Swords

    DTIC Science & Technology

    2013-06-01

    transformed social life within Europe and the values we now associate with progress, like gender equality . After all, if European women ware capable of...than all of the EU members combined and nearly equals the rest of the world in defense spending.9 Europe is to a degree dependent on these...in neighboring kingdoms to battle on their behalf. The only certainty was future conflict, change, and a re- realignment of life in Europe at all

  20. Girls, Bullying Behaviours and Peer Relationships: The Double Edged Sword of Exclusion and Rejection.

    ERIC Educational Resources Information Center

    Leckie, Barbara

    This paper discusses the outcomes of a study on indirect bullying behaviors in girls and the link between girls' peer relationships and bullying behaviors. The study used self-report and peer nomination instruments to survey 987 Australian girls in individual classes from Year 6 to Year 10 in 7 South Australian Catholic and independent schools, 5…

  1. The Effects of α-Tocopherol on Bone: A Double-Edged Sword?

    PubMed Central

    Chin, Kok-Yong; Ima-Nirwana, Soelaiman

    2014-01-01

    Recent studies have found conflicting evidence on the role of α-tocopherol (αTF) on bone health. This nonsystematic review aimed to summarize the current evidence on the effects of αTF on bone health from cell culture, animal, and human studies in order to clarify the role of αTF on bone health. Our review found that αTF exerted beneficial, harmful or null effects on bone formation cells. Animal studies generally showed positive effects of αTF supplementation on bone in various models of osteoporosis. However, high-dose αTF was possibly detrimental to bone in normal animals. Human studies mostly demonstrated a positive relationship between αTF, as assessed using high performance liquid chromatography and/or dietary questionnaire, and bone health, as assessed using bone mineral density and/or fracture incidence. Three possible reasons high dosage of αTF can be detrimental to bone include its interference with Vitamin K function on bone, the blocking of the entry of other Vitamin E isomers beneficial to bone, and the role of αTF as a prooxidant. However, these adverse effects have not been shown in human studies. In conclusion, αTF may have a dual role in bone health, whereby in the appropriate doses it is beneficial but in high doses it may be harmful to bone. PMID:24727433

  2. Hydrogen Peroxide and Polyamines Act as Double Edged Swords in Plant Abiotic Stress Responses

    PubMed Central

    Gupta, Kamala; Sengupta, Atreyee; Chakraborty, Mayukh; Gupta, Bhaskar

    2016-01-01

    The specific genetic changes through which plants adapt to the multitude of environmental stresses are possible because of the molecular regulations in the system. These intricate regulatory mechanisms once unveiled will surely raise interesting questions. Polyamines and hydrogen peroxide have been suggested to be important signaling molecules during biotic and abiotic stresses. Hydrogen peroxide plays a versatile role from orchestrating physiological processes to stress response. It helps to achieve acclimatization and tolerance to stress by coordinating intra-cellular and systemic signaling systems. Polyamines, on the other hand, are low molecular weight polycationic aliphatic amines, which have been implicated in various stress responses. It is quite interesting to note that both hydrogen peroxide and polyamines have a fine line of inter-relation between them since the catabolic pathways of the latter releases hydrogen peroxide. In this review we have tried to illustrate the roles and their multifaceted functions of these two important signaling molecules based on current literature. This review also highlights the fact that over accumulation of hydrogen peroxide and polyamines can be detrimental for plant cells leading to toxicity and pre-mature cell death. PMID:27672389

  3. The microbiota and chronic kidney diseases: a double-edged sword.

    PubMed

    Felizardo, Raphael Jose Ferreira; Castoldi, Angela; Andrade-Oliveira, Vinicius; Câmara, Niels Olsen Saraiva

    2016-06-01

    Recent findings regarding the influence of the microbiota in many inflammatory processes have provided a new way to treat diseases. Now, one may hypothesize that the origin of a plethora of diseases is related to the health of the gut microbiota and its delicate, although complex, interface with the epithelial and immune systems. The 'westernization' of diets, for example, is associated with alterations in the gut microbiota. Such alterations have been found to correlate directly with the increased incidence of diabetes and hypertension, the main causes of chronic kidney diseases (CKDs), which, in turn, have a high estimated prevalence. Indeed, data have arisen showing that the progression of kidney diseases is strictly related to the composition of the microbiota. Alterations in the gut microbiota diversity during CKDs do not only have the potential to exacerbate renal injury but may also contribute to the development of associated comorbidities, such as cardiovascular diseases and insulin resistance. In this review, we discuss how dysbiosis through alterations in the gut barrier and the consequent activation of immune system could intensify the progression of CKD and vice versa, how CKDs can modify the gut microbiota diversity and abundance.

  4. The microbiota and chronic kidney diseases: a double-edged sword

    PubMed Central

    Felizardo, Raphael Jose Ferreira; Castoldi, Angela; Andrade-Oliveira, Vinicius; Câmara, Niels Olsen Saraiva

    2016-01-01

    Recent findings regarding the influence of the microbiota in many inflammatory processes have provided a new way to treat diseases. Now, one may hypothesize that the origin of a plethora of diseases is related to the health of the gut microbiota and its delicate, although complex, interface with the epithelial and immune systems. The ‘westernization' of diets, for example, is associated with alterations in the gut microbiota. Such alterations have been found to correlate directly with the increased incidence of diabetes and hypertension, the main causes of chronic kidney diseases (CKDs), which, in turn, have a high estimated prevalence. Indeed, data have arisen showing that the progression of kidney diseases is strictly related to the composition of the microbiota. Alterations in the gut microbiota diversity during CKDs do not only have the potential to exacerbate renal injury but may also contribute to the development of associated comorbidities, such as cardiovascular diseases and insulin resistance. In this review, we discuss how dysbiosis through alterations in the gut barrier and the consequent activation of immune system could intensify the progression of CKD and vice versa, how CKDs can modify the gut microbiota diversity and abundance. PMID:27757226

  5. Giardia duodenalis: the double-edged sword of immune responses in giardiasis.

    PubMed

    Solaymani-Mohammadi, Shahram; Singer, Steven M

    2010-11-01

    Giardiasis is one of the most common intestinal protozoan infections worldwide. The etiological agent, Giardia duodenalis (syn. Giardia lamblia, Giardia intestinalis), is a flagellated, binucleated protozoan parasite which infects a wide array of mammalian hosts (Adam, 2001). The symptoms of giardiasis include abdominal cramps, nausea, and acute or chronic diarrhea, with malabsorption and failure of children to thrive occurring in both sub-clinical and symptomatic disease (Thompson et al., 1993). Infections are transmitted by cysts which are excreted in the feces of infected humans and animals. Human giardiasis is distributed worldwide, with rates of detection between 2-5% in the developed world and 20-30% in the developing nations (Farthing, 1994). There is significant variation in the outcome of Giardia infections. Most infections are self-limiting, although re-infection is common in endemic areas and chronic infections also occur. Moreover, some individuals suffer from severe cramps, nausea and diarrhea while others escape these overt symptoms. This review will describe recent advances in parasite genetics and host immunity that are helping to shed light on this variability.

  6. Adverse Drug Reactions in Children: The Double-Edged Sword of Therapeutics.

    PubMed

    Elzagallaai, A A; Greff, Mje; Rieder, M J

    2017-06-01

    Adverse drug reactions (ADRs) represent a major health problem worldwide, with high morbidity and mortality rates. ADRs are classified into Type A (augmented) and Type B (bizarre) ADRs, with the former group being more common and the latter less common but often severe and clinically more problematic due to their unpredictable nature and occurrence at any dose. Pediatric populations are especially vulnerable to ADRs due to the lack of data for this age group from the drug development process and because of the wide use of off-label and unlicensed use of drugs. Children are more prone to specific types of ADRs because of the level of maturity of body systems involved in absorption, metabolism, transportation, and elimination of drugs. This state-of-the-art review provides an overview of definitions, classifications, epidemiology, and pathophysiology of ADRs and discusses the available evidence for related risk factors and causes of ADRs in the pediatric population. © 2017 American Society for Clinical Pharmacology and Therapeutics.

  7. The Sensitivity of Precocious Child Writers: More Evidence of the Double-Edged Sword

    ERIC Educational Resources Information Center

    Edmunds, Alan L.; Edmunds, Gail

    2014-01-01

    This article provides further evidence of the often observed sensitive nature displayed by children who are gifted. It also addresses the positive and negative effects that this sensitivity can have on these individuals. Earlier, the authors explored this concept through an analysis of the works and life experiences of Geoffrey, aged 9, a prolific…

  8. Temperate bacterial viruses as double-edged swords in bacterial warfare.

    PubMed

    Gama, João Alves; Reis, Ana Maria; Domingues, Iolanda; Mendes-Soares, Helena; Matos, Ana Margarida; Dionisio, Francisco

    2013-01-01

    It has been argued that bacterial cells may use their temperate viruses as biological weapons. For instance, a few bacterial cells among a population of lysogenic cells could release the virus and kill susceptible non-lysogenic competitors, while their clone mates would be immune. Because viruses replicate inside their victims upon infection, this process would amplify their number in the arena. Sometimes, however, temperate viruses spare recipient cells from death by establishing themselves in a dormant state inside cells. This phenomenon is called lysogenization and, for some viruses such as the λ virus, the probability of lysogenization increases with the multiplicity of infection. Therefore, the amplification of viruses leads to conflicting predictions about the efficacy of temperate viruses as biological weapons: amplification can increase the relative advantage of clone mates of lysogens but also the likelihood of saving susceptible cells from death, because the probability of lysogenization is higher. To test the usefulness of viruses as biological weapons, we performed competition experiments between lysogenic Escherichia coli cells carrying the λ virus and susceptible λ-free E. coli cells, either in a structured or unstructured habitat. In structured and sometimes in unstructured habitats, the λ virus qualitatively behaved as a "replicating toxin". However, such toxic effect of λ viruses ceased after a few days of competition. This was due to the fact that many of initially susceptible cells became lysogenic. Massive lysogenization of susceptible cells occurred precisely under the conditions where the amplification of the virus was substantial. From then on, these cells and their descendants became immune to the λ virus. In conclusion, if at short term bacterial cells may use temperate viruses as biological weapons, after a few days only the classical view of temperate bacterial viruses as parasitic agents prevails.

  9. Double-Edged Sword: Women with Breast Cancer Caring for a Spouse with Cancer.

    PubMed

    Rottenberg, Yakir; Baider, Lea; Jacobs, Jeremy M; Peretz, Tamar; Goldzweig, Gil

    2016-12-01

    Experiences in caregiving may affect further coping with illness. The aim of this study was to assess mortality risk among women diagnosed with breast cancer while caring for a male spouse who had been diagnosed with cancer before or at the time of their own diagnosis. We used a historical prospective study of a nationally representative cohort that was assessed by the Israeli Central Bureau of Statistics 1995 census and followed until 2011. The study population was divided into 2 × 2 groups (according to a positive/negative cancer history of the male spouse before the time of breast cancer diagnosis of the women X spouse alive/dead). The analyses were adjusted for age, ethnicity, breast cancer staging, and time of diagnosis. A total of 14,429 cases of breast cancer and 3,400 deaths were reported during the study period. Mortality was not mediated by the spouse's survival at the time of breast cancer diagnosis of the women. However, decreased risk of death was seen in women with a positive spouse history of cancer when the spouse was alive at the time of diagnosis in women who were diagnosed with breast cancer stages II and III (hazard ratio = 0.76, 95% CI: 0.59-0.98). Among a subset of women diagnosed with breast cancer, there is evidence of a significant protective association between a history of caregiving for cancer of a spouse who is alive at the time of self-diagnosis and subsequent survival. Our findings support hypotheses concerning a positive experience of caregiving and emphasize the need to define the patient and the caregiver as an integrative "unit of care."

  10. Stabilizing versus Destabilizing the Microtubules: A Double-Edge Sword for an Effective Cancer Treatment Option?

    PubMed Central

    Fanale, Daniele; Bronte, Giuseppe; Passiglia, Francesco; Calò, Valentina; Castiglia, Marta; Di Piazza, Florinda; Barraco, Nadia; Cangemi, Antonina; Catarella, Maria Teresa; Insalaco, Lavinia; Listì, Angela; Maragliano, Rossella; Massihnia, Daniela; Perez, Alessandro; Toia, Francesca; Cicero, Giuseppe; Bazan, Viviana

    2015-01-01

    Microtubules are dynamic and structural cellular components involved in several cell functions, including cell shape, motility, and intracellular trafficking. In proliferating cells, they are essential components in the division process through the formation of the mitotic spindle. As a result of these functions, tubulin and microtubules are targets for anticancer agents. Microtubule-targeting agents can be divided into two groups: microtubule-stabilizing, and microtubule-destabilizing agents. The former bind to the tubulin polymer and stabilize microtubules, while the latter bind to the tubulin dimers and destabilize microtubules. Alteration of tubulin-microtubule equilibrium determines the disruption of the mitotic spindle, halting the cell cycle at the metaphase-anaphase transition and, eventually, resulting in cell death. Clinical application of earlier microtubule inhibitors, however, unfortunately showed several limits, such as neurological and bone marrow toxicity and the emergence of drug-resistant tumor cells. Here we review several natural and synthetic microtubule-targeting agents, which showed antitumor activity and increased efficacy in comparison to traditional drugs in various preclinical and clinical studies. Cryptophycins, combretastatins, ombrabulin, soblidotin, D-24851, epothilones and discodermolide were used in clinical trials. Some of them showed antiangiogenic and antivascular activity and others showed the ability to overcome multidrug resistance, supporting their possible use in chemotherapy. PMID:26484003

  11. Dendritic Cells: A Double-Edged Sword in Immune Responses during Chagas Disease

    PubMed Central

    Gil-Jaramillo, Natalia; Motta, Flávia N.; Favali, Cecília B. F.; Bastos, Izabela M. D.; Santana, Jaime M.

    2016-01-01

    Dendritic cells (DCs) are the most important member of the antigen presenting cells group due to their ability to recognize antigen at the infection site and their high specialized antigen internalization capacity. These cells have central role in connecting the innate and adaptive immune responses against Trypanosoma cruzi, the causative agent of Chagas disease. These first line defense cells modulate host immune response depending on type, maturation level, cytokine milieu and DC receptor involved in the interactions with T. cruzi, influencing the development of the disease clinic forms. Here, we present a review of DCs–T. cruzi interactions both in human and murine models, pointing out the parasite ability to manipulate DCs activity for the purpose of evading innate immune response and assuring its own survival and persistence. PMID:27471496

  12. The DLK signalling pathway--a double-edged sword in neural development and regeneration.

    PubMed

    Tedeschi, Andrea; Bradke, Frank

    2013-07-01

    Dual leucine zipper kinase (DLK), a mitogen-activated protein kinase kinase kinase, controls axon growth, apoptosis and neuron degeneration during neural development, as well as neurodegeneration after various insults to the adult nervous system. Interestingly, recent studies have also highlighted a role of DLK in promoting axon regeneration in diverse model systems. Invertebrates and vertebrates, cold- and warm-blooded animals, as well as central and peripheral mammalian nervous systems all differ in their ability to regenerate injured axons. Here, we discuss how DLK-dependent signalling regulates apparently contradictory functions during neural development and regeneration in different species. In addition, we outline strategies to fine-tune DLK function, either alone or together with other approaches, to promote axon regeneration in the adult mammalian central nervous system.

  13. Modulatory effects of mesenchymal stem cells on leucocytes and leukemic cells: A double-edged sword?

    PubMed

    Low, Jun How; Ramdas, Premdass; Radhakrishnan, Ammu Kutty

    2015-12-01

    Mesenchymal stem cells (MSCs) have drawn much attention amongst stem cell researchers in the past few decades. The ability of the MSC to differentiate into cells of mesodermal and non-mesodermal origins has made them an attractive approach for cell-based therapy and regenerative medicine. The MSCs have immunosuppressive activities that may have considerable therapeutic values in autoimmune diseases. However, despite the many beneficial effects reported, there is a growing body of evidence, which suggests that MSCs could be a culprit of enhanced tumour growth, metastasis and drug resistance in leukaemia, via some modulatory effects. Many controversies regarding the interactions between MSCs and leukaemia still exist. Furthermore, the role of MSCs in leukemogenesis and its progression remain largely unknown. Hence it is important to understand how the MSCs modulate leukaemia before these cells could be safely used in the treatment of leukaemia patients.

  14. Education Policy Reform in Sri Lanka: The Double-Edged Sword of Political Will

    ERIC Educational Resources Information Center

    Little, Angela W.

    2011-01-01

    In 1997, the Government of Sri Lanka launched a comprehensive set of education reforms designed to promote equitable access to basic education and improvements in learning outcomes. The package of reforms arose as a political response to widespread youth unrest in the late 1980s and attracted considerable "political will", a vague but…

  15. Education Policy Reform in Sri Lanka: The Double-Edged Sword of Political Will

    ERIC Educational Resources Information Center

    Little, Angela W.

    2011-01-01

    In 1997, the Government of Sri Lanka launched a comprehensive set of education reforms designed to promote equitable access to basic education and improvements in learning outcomes. The package of reforms arose as a political response to widespread youth unrest in the late 1980s and attracted considerable "political will", a vague but…

  16. The double-edged sword of electronic health records: implications for patient disclosure.

    PubMed

    Campos-Castillo, Celeste; Anthony, Denise L

    2015-04-01

    Electronic health record (EHR) systems are linked to improvements in quality of care, yet also privacy and security risks. Results from research studies are mixed about whether patients withhold personal information from their providers to protect against the perceived EHR privacy and security risks. This study seeks to reconcile the mixed findings by focusing on whether accounting for patients' global ratings of care reveals a relationship between EHR provider-use and patient non-disclosure. A nationally representative sample from the 2012 Health Information National Trends Survey was analyzed using bivariate and multivariable logit regressions to examine whether global ratings of care suppress the relationship between EHR provider-use and patient non-disclosure. 13% of respondents reported having ever withheld information from a provider because of privacy/security concerns. Bivariate analysis showed that withholding information was unrelated to whether respondents' providers used an EHR. Multivariable analysis showed that accounting for respondents' global ratings of care revealed a positive relationship between having a provider who uses an EHR and withholding information. After accounting for global ratings of care, findings suggest that patients may non-disclose to providers to protect against the perceived EHR privacy and security risks. Despite evidence that EHRs inhibit patient disclosure, their advantages for promoting quality of care may outweigh the drawbacks. Clinicians should leverage the EHR's value in quality of care and discuss patients' privacy concerns during clinic visits, while policy makers should consider how to address the real and perceived privacy and security risks of EHRs. © The Author 2014. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. The Double-edged Sword of Pedagogy: Instruction limits spontaneous exploration and discovery

    PubMed Central

    Shafto, Patrick; Gweon, Hyowon; Goodman, Noah D.; Spelke, Elizabeth; Schulz, Laura

    2012-01-01

    Motivated by computational analyses, we look at how teaching affects exploration and discovery. In Experiment 1, we investigated children’s exploratory play after an adult pedagogically demonstrated a function of a toy, after an interrupted pedagogical demonstration, after a naïve adult demonstrated the function, and at baseline. Preschoolers in the pedagogical condition focused almost exclusively on the target function; by contrast, children in the other conditions explored broadly. In Experiment 2, we show that children restrict their exploration both after direct instruction to themselves and after overhearing direct instruction given to another child; they do not show this constraint after observing direct instruction given to an adult or after observing a non-pedagogical intentional action. We discuss these findings as the result of rational inductive biases. In pedagogical contexts, a teacher’s failure to provide evidence for additional functions provides evidence for their absence; such contexts generalize from child to child (because children are likely to have comparable states of knowledge) but not from adult to child. Thus, pedagogy promotes efficient learning but at a cost: children are less likely to perform potentially irrelevant actions but also less likely to discover novel information. PMID:21216395

  18. Protecting Chemistry Inventions: The Double-Edged Sword of Being an Unpredictable Art

    PubMed Central

    2015-01-01

    Recent decisions by the highest courts in the US in regard to written description and enablement as well as parallel restrictions previously established in Europe emphasize that applicants in the fields of chemistry/pharma/life sciences should strive to include as many examples, data, and guidance about how to extrapolate from the example(s) in the description. This holds in particular whenever a broad genus and/or functional features is/are to be protected. It is important to keep in mind that these data and this guidance must be disclosed in the application at the time of filing. Data collected at a later stage can only be used to further support data and evidence already present in the application as filed. PMID:25941548

  19. Signaling via MYD88 in the pancreatic tumor microenvironment: A double-edged sword.

    PubMed

    Zambirinis, Constantinos P; Miller, George

    2013-01-01

    We have recently shown that Toll-like receptor (TLR) signaling exacerbates pancreatic fibro-inflammation and promotes carcinogenesis in mice. Paradoxically, inhibition of the TLR-MYD88 signaling pathway is pro-tumorigenic owing to the dendritic cell-mediated TH2-polarization of CD4(+) T cells. TLR signaling appears to be central in pancreatic cancer-associated inflammation.

  20. "My Past Is a Double Edge Sword": Temporality and Reflexivity in Mature Learners

    ERIC Educational Resources Information Center

    Stevenson, Jacqueline; Clegg, Sue

    2013-01-01

    This paper discusses the ways in which mature students orientate themselves towards the future in making decisions to access higher education (HE). Their narratives connect their past, often difficult, educational and personal lives to their future aspirations and to their current experiences in further education (FE) and HE. The research was part…

  1. A Double-Edged Sword: Assessing the Impact of Tuition Discounting.

    ERIC Educational Resources Information Center

    Hubbell, Loren W. Loomis; Rush, Sean C.

    1991-01-01

    A discussion of the interrelationships between college tuition pricing, family resources, externally funded financial aid, and institutionally funded financial aid suggests that, as the range of tuition levels broadens, institutions must focus more closely on net tuition income in their forecasting or face erosion of revenues. (MSE)

  2. Microglia-blood vessel interactions: a double-edged sword in brain pathologies.

    PubMed

    Dudvarski Stankovic, Nevenka; Teodorczyk, Marcin; Ploen, Robert; Zipp, Frauke; Schmidt, Mirko H H

    2016-03-01

    Microglia are long-living resident immune cells of the brain, which secure a stable chemical and physical microenvironment necessary for the proper functioning of the central nervous system (CNS). These highly dynamic cells continuously scan their environment for pathogens and possess the ability to react to damage-induced signals in order to protect the brain. Microglia, together with endothelial cells (ECs), pericytes and astrocytes, form the functional blood-brain barrier (BBB), a specialized endothelial structure that selectively separates the sensitive brain parenchyma from blood circulation. Microglia are in bidirectional and permanent communication with ECs and their perivascular localization enables them to survey the influx of blood-borne components into the CNS. Furthermore, they may stimulate the opening of the BBB, extravasation of leukocytes and angiogenesis. However, microglia functioning requires tight control as their dysregulation is implicated in the initiation and progression of numerous neurological diseases. Disruption of the BBB, changes in blood flow, introduction of pathogens in the sensitive CNS niche, insufficient nutrient supply, and abnormal secretion of cytokines or expression of endothelial receptors are reported to prime and attract microglia. Such reactive microglia have been reported to even escalate the damage of the brain parenchyma as is the case in ischemic injuries, brain tumors, multiple sclerosis, Alzheimer's and Parkinson's disease. In this review, we present the current state of the art of the causes and mechanisms of pathological interactions between microglia and blood vessels and explore the possibilities of targeting those dysfunctional interactions for the development of future therapeutics.

  3. "My Past Is a Double Edge Sword": Temporality and Reflexivity in Mature Learners

    ERIC Educational Resources Information Center

    Stevenson, Jacqueline; Clegg, Sue

    2013-01-01

    This paper discusses the ways in which mature students orientate themselves towards the future in making decisions to access higher education (HE). Their narratives connect their past, often difficult, educational and personal lives to their future aspirations and to their current experiences in further education (FE) and HE. The research was part…

  4. Levodopa-induced plasticity: a double-edged sword in Parkinson's disease?

    PubMed

    Calabresi, Paolo; Ghiglieri, Veronica; Mazzocchetti, Petra; Corbelli, Ilenia; Picconi, Barbara

    2015-07-05

    The long-term replacement therapy with the dopamine (DA) precursor 3,4-dihydroxy-l-phenylalanine (L-DOPA) is a milestone in the treatment of Parkinson's disease (PD). Although this drug precursor can be metabolized into the active neurotransmitter DA throughout the brain, its therapeutic benefit is due to restoring extracellular DA levels within the dorsal striatum, which lacks endogenous DA as a consequence of the neurodegenerative process induced by the disease. In the early phases of PD, L-DOPA treatment is able to restore both long-term depression (LTD) and long-term potentiation (LTP), two major forms of corticostriatal synaptic plasticity that are altered by dopaminergic denervation. However, unlike physiological DA transmission, this therapeutic approach in the advanced phase of the disease leads to abnormal peaks of DA, non-synaptically released, which are supposed to trigger behavioural sensitization, namely L-DOPA-induced dyskinesia. This condition is characterized by a loss of synaptic depotentiation, an inability to reverse previously induced LTP. In the advanced stages of PD, L-DOPA can also induce non-motor fluctuations with cognitive dysfunction and neuropsychiatric symptoms such as compulsive behaviours and impulse control disorders. Although the mechanisms underlying the role of L-DOPA in both motor and behavioural symptoms are still incompletely understood, recent data from electrophysiological and imaging studies have increased our understanding of the function of the brain areas involved and of the mechanisms implicated in both therapeutic and adverse actions of L-DOPA in PD patients.

  5. The Double-Edged Sword: Critical Reflections on Traditional and Modern Technology in Outdoor Education

    ERIC Educational Resources Information Center

    Cuthbertson, Brent; Socha, Teresa L.; Potter, Tom G.

    2004-01-01

    The outdoor education experience continues to be influenced by a proliferation of modern technological innovations, most of which have been accepted and even embraced by educators with little inquiry. Seldom do instructors of outdoor programmes consider the impact that modern techniques and equipment can have upon students' learning. This paper…

  6. The mating sociometer and attractive others: a double-edged sword in romantic relationships.

    PubMed

    Kavanagh, Phillip Sean; Fletcher, Garth J O; Ellis, Bruce J

    2014-01-01

    Eighty-one participants were recruited to test the sensitivity of the mating sociometer to mate-value feedback in the context of ongoing intimate relationships. Experiences of social rejection/acceptance by attractive opposite-sex confederates were manipulated. The effects of this manipulation on self-esteem, relationship satisfaction and commitment, perceptions of dating alternatives, and friendship-dedication were assessed. Social rejection/acceptance by members of the opposite sex altered relationship satisfaction and commitment; this causal link was amplified by changes in state self-esteem; and these effects were specific to intimate relationships and did not generalize to friendship-dedication. This research supports a domain-specific conceptualization of sociometer theory, extending the theory in important directions.

  7. The Sensitivity of Precocious Child Writers: More Evidence of the Double-Edged Sword

    ERIC Educational Resources Information Center

    Edmunds, Alan L.; Edmunds, Gail

    2014-01-01

    This article provides further evidence of the often observed sensitive nature displayed by children who are gifted. It also addresses the positive and negative effects that this sensitivity can have on these individuals. Earlier, the authors explored this concept through an analysis of the works and life experiences of Geoffrey, aged 9, a prolific…

  8. A double-edged sword: Benefits and pitfalls of heterogeneous punishment in evolutionary inspection games

    NASA Astrophysics Data System (ADS)

    Perc, Matjaž; Szolnoki, Attila

    2015-06-01

    As a simple model for criminal behavior, the traditional two-strategy inspection game yields counterintuitive results that fail to describe empirical data. The latter shows that crime is often recurrent, and that crime rates do not respond linearly to mitigation attempts. A more apt model entails ordinary people who neither commit nor sanction crime as the third strategy besides the criminals and punishers. Since ordinary people free-ride on the sanctioning efforts of punishers, they may introduce cyclic dominance that enables the coexistence of all three competing strategies. In this setup ordinary individuals become the biggest impediment to crime abatement. We therefore also consider heterogeneous punisher strategies, which seek to reduce their investment into fighting crime in order to attain a more competitive payoff. We show that this diversity of punishment leads to an explosion of complexity in the system, where the benefits and pitfalls of criminal behavior are revealed in the most unexpected ways. Due to the raise and fall of different alliances no less than six consecutive phase transitions occur in dependence on solely the temptation to succumb to criminal behavior, leading the population from ordinary people-dominated across punisher-dominated to crime-dominated phases, yet always failing to abolish crime completely.

  9. LandCyber Operations: A Double Edged Sword or a Dream Team?

    DTIC Science & Technology

    2013-03-01

    power, economic tension and overpopulation are but a few of the underlying conditions that will foment conflict in the 21st century. History has...Commanders are not the only cause of mission command failure; often it is the inexperienced subordinate who lacks the intuitive ability to see

  10. A double-edged sword: Benefits and pitfalls of heterogeneous punishment in evolutionary inspection games

    PubMed Central

    Perc, Matjaž; Szolnoki, Attila

    2015-01-01

    As a simple model for criminal behavior, the traditional two-strategy inspection game yields counterintuitive results that fail to describe empirical data. The latter shows that crime is often recurrent, and that crime rates do not respond linearly to mitigation attempts. A more apt model entails ordinary people who neither commit nor sanction crime as the third strategy besides the criminals and punishers. Since ordinary people free-ride on the sanctioning efforts of punishers, they may introduce cyclic dominance that enables the coexistence of all three competing strategies. In this setup ordinary individuals become the biggest impediment to crime abatement. We therefore also consider heterogeneous punisher strategies, which seek to reduce their investment into fighting crime in order to attain a more competitive payoff. We show that this diversity of punishment leads to an explosion of complexity in the system, where the benefits and pitfalls of criminal behavior are revealed in the most unexpected ways. Due to the raise and fall of different alliances no less than six consecutive phase transitions occur in dependence on solely the temptation to succumb to criminal behavior, leading the population from ordinary people-dominated across punisher-dominated to crime-dominated phases, yet always failing to abolish crime completely. PMID:26046673

  11. Teaching Mathematics by Comparison: Analog Visibility as a Double-Edged Sword

    ERIC Educational Resources Information Center

    Begolli, Kreshnik Nasi; Richland, Lindsey Engle

    2016-01-01

    Comparing multiple solutions to a single problem is an important mode for developing flexible mathematical thinking, yet instructionally leading this activity is challenging (Stein, Engle, Smith, & Hughes, 2008). We test 1 decision teachers must make after having students solve a problem: whether to only verbally discuss students' solutions or…

  12. Familiarity, ambivalence, and firm reputation: is corporate fame a double-edged sword?

    PubMed

    Brooks, Margaret E; Highhouse, Scott; Russell, Steven S; Mohr, David C

    2003-10-01

    This research questioned the proposition that corporate familiarity is positively associated with firm reputation. Student images of familiar and unfamiliar Fortune 500 corporations were examined in 4 experiments. The results suggested that, consistent with behavioral decision theory and attitude theory, highly familiar corporations provide information that is more compatible with the tasks of both admiring and condemning than less familiar corporations. Furthermore, the judgment context may determine whether positive or negative judgments are reported about familiar companies. The notion that people can simultaneously hold contradictory images of well-known firms may help to explain the inconsistent findings on the relation between familiarity and reputation.

  13. Double-edged sword of radiotherapy: a cause of secondary angiosarcoma after breast conservation therapy.

    PubMed

    Iqbal, Fahad Mujtaba; Ahmed, Balen; Vidya, Raghavan

    2016-04-25

    Angiosarcomas are rare and aggressive malignant tumours of vascular or endothelial origin that can originate in the breast. They can be classified as primary or secondary, with the latter most commonly due to postoperative radiotherapy as part of breast conservation therapy (wide local excision and adjuvant radiotherapy) for breast cancer. We report a case of postirradiation secondary angiosarcoma in a 56-year-old woman, alongside a review of the current literature, to inform clinicians of its clinical presentation and characteristics as a high index of clinical suspicion is required for an accurate diagnosis. 2016 BMJ Publishing Group Ltd.

  14. The Double-Edged Sword of "Disaster Volunteerism": A Study of New Orleans Rebirth Movement Participants

    ERIC Educational Resources Information Center

    Heldman, Caroline; Israel-Trummel, Mackenzie

    2012-01-01

    We examine the political and personal effects of disaster volunteerism with participants of the New Orleans Rebirth Movement (NORM) using four waves of pre- and postsurveys and qualitative analysis of participant journals. Significant increases are found in internal political efficacy, desire to be active in politics, and value placed on social…

  15. Selenium: a double-edged sword for defense and offence in cancer.

    PubMed

    Brozmanová, Jela; Mániková, Dominika; Vlčková, Viera; Chovanec, Miroslav

    2010-12-01

    Selenium (Se) is an essential dietary component for animals including humans and is regarded as a protective agent against cancer. Although the mode of anticancer action of Se is not fully understood yet, several mechanisms, such as antioxidant protection by selenoenzymes, specific inhibition of tumor cell growth by Se metabolites, modulation of cell cycle and apoptosis, and effect on DNA repair have all been proposed. Despite the unsupported results of the last SELECT trial, the cancer-preventing activity of Se was demonstrated in majority of the epidemiological studies. Moreover, recent studies suggest that Se has a potential to be used not only in cancer prevention but also in cancer treatment where in combination with other anticancer drugs or radiation, it can increase efficacy of cancer therapy. In combating cancer cells, Se acts as pro-oxidant rather than antioxidant, inducing apoptosis through the generation of oxidative stress. Thus, the inorganic Se compound, sodium selenite (SeL), due to its prooxidant character, represents a promising alternative for cancer therapy. However, this Se compound is highly toxic compared to organic Se forms. Thus, the unregulated intake of dietary or pharmacological Se supplements mainly in the form of SeL has a potential to expose the body tissues to the toxic levels of Se with subsequent negative consequences on DNA integrity. Hence, due to a broad interest to exploit the positive effects of Se on human health and cancer therapy, studies investigating the negative effects such as toxicity and DNA damage induction resulting from high Se intake are also highly required. Here, we review a role of Se in cancer prevention and cancer therapy, as well as mechanisms underlying Se-induced toxicity and DNA injury. Since Saccharomyces cerevisiae has proven a powerful tool for addressing some important questions regarding Se biology, a part of this review is devoted to this model system.

  16. Epoxyeicosatrienoic acids: a double-edged sword in cardiovascular diseases and cancer

    PubMed Central

    Wang, Dingzhi; DuBois, Raymond N.

    2011-01-01

    Epoxyeicosatrienoic acids (EETs) generated from arachidonic acid by cytochrome P450 (CYP) epoxygenases have beneficial effects in certain cardiovascular and kidney diseases. Hence, great efforts have been made to develop drugs targeting the EET pathway. Some of these agents are currently under evaluation in clinical trials for treatment of hypertension and diabetes. In this issue of the JCI, Panigrahy et al. evaluate in a systematic way the role of CYP epoxygenases and the metabolites they generate in cancer progression. Their findings, along with previous studies, raise concerns about using these drugs in humans. PMID:22182836

  17. Double-Edged Sword: Musculoskeletal Infection Provoked Acute Phase Response in Children.

    PubMed

    Benvenuti, Michael; An, Thomas; Amaro, Emilie; Lovejoy, Steven; Mencio, Gregory; Martus, Jeffrey; Mignemi, Megan; Schoenecker, Jonathan G

    2017-04-01

    The acute phase response has a crucial role in mounting the body's response to tissue injury. Excessive activation of the acute phase response is responsible for many complications that occur in orthopedic patients. Given that infection may be considered continuous tissue injury that persistently activates the acute phase response, children with musculoskeletal infections are at markedly increased risk for serious complications. Future strategies that modulate the acute phase response have the potential to improve treatment and prevent complications associated with musculoskeletal infection. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Pattern recognition receptors and cytokines in Mycobacterium tuberculosis infection--the double-edged sword?

    PubMed

    Hossain, Md Murad; Norazmi, Mohd-Nor

    2013-01-01

    Tuberculosis, an infectious disease caused by Mycobacterium tuberculosis (Mtb), remains a major cause of human death worldwide. Innate immunity provides host defense against Mtb. Phagocytosis, characterized by recognition of Mtb by macrophages and dendritic cells (DCs), is the first step of the innate immune defense mechanism. The recognition of Mtb is mediated by pattern recognition receptors (PRRs), expressed on innate immune cells, including toll-like receptors (TLRs), complement receptors, nucleotide oligomerization domain like receptors, dendritic cell-specific intercellular adhesion molecule grabbing nonintegrin (DC-SIGN), mannose receptors, CD14 receptors, scavenger receptors, and FCγ receptors. Interaction of mycobacterial ligands with PRRs leads macrophages and DCs to secrete selected cytokines, which in turn induce interferon-γ- (IFNγ-) dominated immunity. IFNγ and other cytokines like tumor necrosis factor-α (TNFα) regulate mycobacterial growth, granuloma formation, and initiation of the adaptive immune response to Mtb and finally provide protection to the host. However, Mtb can evade destruction by antimicrobial defense mechanisms of the innate immune system as some components of the system may promote survival of the bacteria in these cells and facilitate pathogenesis. Thus, although innate immunity components generally play a protective role against Mtb, they may also facilitate Mtb survival. The involvement of selected PRRs and cytokines on these seemingly contradictory roles is discussed.

  19. Schisandrin B: A Double-Edged Sword in Nonalcoholic Fatty Liver Disease

    PubMed Central

    2016-01-01

    Nonalcoholic fatty liver disease (NAFLD) is a spectrum of liver lesions ranging from hepatic steatosis, nonalcoholic steatohepatitis, hepatic cirrhosis, and hepatocellular carcinoma. The high global prevalence of NAFLD has underlined the important public health implications of this disease. The pathogenesis of NAFLD involves the abnormal accumulation of free fatty acids, oxidative stress, endoplasmic reticulum (ER) stress, and a proinflammatory state in the liver. Schisandrin B (Sch B), an active dibenzooctadiene lignan isolated from the fruit of Schisandra chinensis (a traditional Chinese herb), was found to possess antihyperlipidemic, antioxidant, anti-ER stress, and anti-inflammatory activities in cultured hepatocytes in vitro and in rodent livers in vivo. Whereas a long-term, low dose regimen of Sch B induces an antihyperlipidemic response in obese mice fed a high fat diet, a single bolus high dose of Sch B increases serum/hepatic lipid levels in mice. This differential action of Sch B is likely related to a dose/time-dependent biphasic response on lipid metabolism in mice. The hepatoprotection afforded by Sch B against oxidative stress, ER stress, and inflammation has been widely reported. The ensemble of results suggests that Sch B may offer potential as a therapeutic agent for NAFLD. The optimal dose and duration of Sch B treatment need to be established in order to ensure maximal efficacy and safety when used in humans. PMID:27847552

  20. Chinese Sex-Role Conceptions: A Double Edged Sword for Women.

    ERIC Educational Resources Information Center

    Korabik, Karen

    Although Chinese government policies officially support the equality of the sexes, stereotyped views about the nature of men and women often serve to perpetuate discrimination and to keep women in inferior positions. Women are often segregated into lower paying jobs because of stereotypical views about what is natural for women to do. Despite…

  1. Wnt/β-catenin signaling in kidney injury and repair: a double-edged sword

    PubMed Central

    Zhou, Dong; Tan, Roderick J.; Fu, Haiyan; Liu, Youhua

    2015-01-01

    The Wnt/β-catenin signaling cascade is an evolutionarily conserved, highly complex pathway that is known to be involved in kidney injury and repair after a wide variety of insults. While the kidney displays an impressive ability to repair and recover after injury, these repair mechanisms can be overwhelmed, leading to maladaptive responses and eventual development of chronic kidney disease (CKD). Emerging evidence demonstrates that Wnt/β-catenin signaling possesses dual roles in promoting repair/regeneration or facilitating progression to CKD after acute kidney injury (AKI), depending on the magnitude and duration of its activation. In this review, we summarize the expression, intracellular modification, and secretion of Wnt family proteins and their regulation in a variety of kidney diseases. We also explore our current understanding of the potential mechanisms by which transient Wnt/β-catenin activation positively regulates adaptive responses of the kidney after AKI, and discuss how sustained activation of this signaling triggers maladaptive responses and causes destructive outcomes. A better understanding of these mechanisms may offer important opportunities for designing targeted therapy to promote adaptive kidney repair/recovery and prevent progression to CKD in patients. PMID:26692289

  2. Protecting chemistry inventions: the double-edged sword of being an unpredictable art.

    PubMed

    Tostmann, Holger

    2015-04-09

    Recent decisions by the highest courts in the US in regard to written description and enablement as well as parallel restrictions previously established in Europe emphasize that applicants in the fields of chemistry/pharma/life sciences should strive to include as many examples, data, and guidance about how to extrapolate from the example(s) in the description. This holds in particular whenever a broad genus and/or functional features is/are to be protected. It is important to keep in mind that these data and this guidance must be disclosed in the application at the time of filing. Data collected at a later stage can only be used to further support data and evidence already present in the application as filed.

  3. Induced plant defences in biological control of arthropod pests: a double-edged sword.

    PubMed

    Pappas, Maria L; Broekgaarden, Colette; Broufas, George D; Kant, Merijn R; Messelink, Gerben J; Steppuhn, Anke; Wäckers, Felix; van Dam, Nicole M

    2017-09-01

    Biological control is an important ecosystem service delivered by natural enemies. Together with breeding for plant defence, it constitutes one of the most promising alternatives to pesticides for controlling herbivores in sustainable crop production. Especially induced plant defences may be promising targets in plant breeding for resistance against arthropod pests. Because they are activated upon herbivore damage, costs are only incurred when defence is needed. Moreover, they can be more specific than constitutive defences. Nevertheless, inducible defence traits that are harming plant pest organisms may interfere with biological control agents, such as predators and parasitoids. Despite the vast fundamental knowledge on plant defence mechanisms and their effects on natural enemies, our understanding of the feasibility of combining biological control with induced plant defence in practice is relatively poor. In this review, we focus on arthropod pest control and present the most important features of biological control with natural enemies and of induced plant defence. Furthermore, we show potential synergies and conflicts among them and, finally, identify gaps and list opportunities for their combined use in crop protection. We suggest that breeders should focus on inducible resistance traits that are compatible with the natural enemies of arthropod pests, specifically traits that help communities of natural enemies to build up. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

  4. The Double-Edged Sword of Goal Engagement: Consequences of Goal Pursuit in Bipolar Disorder

    PubMed Central

    Johnson, Sheri L.; Fulford, Daniel; Carver, Charles S.

    2012-01-01

    A series of studies suggest that bipolar disorder is related to high sensitivity to incentives and that incentive sensitivity (or sensitivity of the approach system) can predict the course of mania. Incentive sensitivity in bipolar disorder seems to be related to two processes: a tendency to invest in difficult-to-attain goals and an over-reactivity to cues of goal progress versus thwarting. Both of those processes appear relevant to symptom generation. Hence, bipolar disorder seems related to a greater emphasis on reaching goals and also a problematic reactivity to reaching those highly desired goals. We suggest directions for treatment development focused on these issues in goal regulation. PMID:22610999

  5. The Evolving Functions of Autophagy in Ocular Health: A Double-edged Sword

    PubMed Central

    Chai, Peiwei; Ni, Hongyan; Zhang, He; Fan, Xianqun

    2016-01-01

    Autophagy plays an adaptive role in cell survival, development, differentiation and intracellular homeostasis. Autophagy is recognized as a 'self-cannibalizing' process that is active during stresses such as starvation, chemotherapy, infection, ageing, and oxygen shortage to protect organisms from various irritants and to regenerate materials and energy. However, autophagy can also lead to a form of programmed cell death distinct from apoptosis. Components of the autophagic pathway are constitutively expressed at a high level in the eye, including in the cornea, lens, retina, and orbit. In addition, the activation of autophagy is directly linked to the development of eye diseases such as age-related macular degeneration (ARMD), cataracts, diabetic retinopathy (DR), glaucoma, photoreceptor degeneration, ocular tumours, ocular infections and thyroid-associated ophthalmopathy (TAO). A high level of autophagy defends against external stress; however, excessive autophagy can result in deterioration, as observed in ocular diseases such as ARMD and DR. This review summarizes recent developments elucidating the relationship between autophagy and ocular diseases and the potential roles of autophagy in the pathogenesis and treatment of these diseases. PMID:27877085

  6. Levodopa-induced plasticity: a double-edged sword in Parkinson's disease?

    PubMed Central

    Calabresi, Paolo; Ghiglieri, Veronica; Mazzocchetti, Petra; Corbelli, Ilenia; Picconi, Barbara

    2015-01-01

    The long-term replacement therapy with the dopamine (DA) precursor 3,4-dihydroxy-l-phenylalanine (L-DOPA) is a milestone in the treatment of Parkinson's disease (PD). Although this drug precursor can be metabolized into the active neurotransmitter DA throughout the brain, its therapeutic benefit is due to restoring extracellular DA levels within the dorsal striatum, which lacks endogenous DA as a consequence of the neurodegenerative process induced by the disease. In the early phases of PD, L-DOPA treatment is able to restore both long-term depression (LTD) and long-term potentiation (LTP), two major forms of corticostriatal synaptic plasticity that are altered by dopaminergic denervation. However, unlike physiological DA transmission, this therapeutic approach in the advanced phase of the disease leads to abnormal peaks of DA, non-synaptically released, which are supposed to trigger behavioural sensitization, namely L-DOPA-induced dyskinesia. This condition is characterized by a loss of synaptic depotentiation, an inability to reverse previously induced LTP. In the advanced stages of PD, L-DOPA can also induce non-motor fluctuations with cognitive dysfunction and neuropsychiatric symptoms such as compulsive behaviours and impulse control disorders. Although the mechanisms underlying the role of L-DOPA in both motor and behavioural symptoms are still incompletely understood, recent data from electrophysiological and imaging studies have increased our understanding of the function of the brain areas involved and of the mechanisms implicated in both therapeutic and adverse actions of L-DOPA in PD patients. PMID:26009763

  7. Autophagy: a double-edged sword for neuronal survival after cerebral ischemia

    PubMed Central

    Chen, Wenqi; Sun, Yinyi; Liu, Kangyong; Sun, Xiaojiang

    2014-01-01

    Evidence suggests that autophagy may be a new therapeutic target for stroke, but whether activation of autophagy increases or decreases the rate of neuronal death is still under debate. This review summarizes the potential role and possible signaling pathway of autophagy in neuronal survival after cerebral ischemia and proposes that autophagy has dual effects. PMID:25206784

  8. The DLK signalling pathway—a double-edged sword in neural development and regeneration

    PubMed Central

    Tedeschi, Andrea; Bradke, Frank

    2013-01-01

    Dual leucine zipper kinase (DLK), a mitogen-activated protein kinase kinase kinase, controls axon growth, apoptosis and neuron degeneration during neural development, as well as neurodegeneration after various insults to the adult nervous system. Interestingly, recent studies have also highlighted a role of DLK in promoting axon regeneration in diverse model systems. Invertebrates and vertebrates, cold- and warm-blooded animals, as well as central and peripheral mammalian nervous systems all differ in their ability to regenerate injured axons. Here, we discuss how DLK-dependent signalling regulates apparently contradictory functions during neural development and regeneration in different species. In addition, we outline strategies to fine-tune DLK function, either alone or together with other approaches, to promote axon regeneration in the adult mammalian central nervous system. PMID:23681442

  9. The loyal dissident: N.A. Bernstein and the double-edged sword of Stalinism.

    PubMed

    Meijer, Onno G; Bruijn, Sjoerd M

    2007-01-01

    Nikolai Aleksandrovich Bernstein (1896-1966) studied movement in order to understand the brain. Contra Pavlov, he saw movements (thus, the brain) as coordinated. For Bernstein, the cortex was a stochastic device; the more cortexes an animal species has, the more variable its actions will be. Actions are planned with a stochastic "model of the future," and relevance is established through blind mathematical search. In the 1950 neoPavlovian affair, he came under strong attack and had to stop experimenting. It is argued that the consistency of his work derived both from both dialectical materialism and the relentless attacks of the neoPavlovians.

  10. The Double-Edged Sword of "Disaster Volunteerism": A Study of New Orleans Rebirth Movement Participants

    ERIC Educational Resources Information Center

    Heldman, Caroline; Israel-Trummel, Mackenzie

    2012-01-01

    We examine the political and personal effects of disaster volunteerism with participants of the New Orleans Rebirth Movement (NORM) using four waves of pre- and postsurveys and qualitative analysis of participant journals. Significant increases are found in internal political efficacy, desire to be active in politics, and value placed on social…

  11. Is referral to a spine surgeon a double-edged sword?: patient concerns before consultation.

    PubMed

    Kidane, Biniam; Gandhi, Rajiv; Sarro, Angela; Valiante, Taufik A; Harvey, Bart J; Rampersaud, Y Raja

    2011-07-01

    To assess the concerns of adult patients with spine-related complaints during the period between referral to and consultation with a spine surgeon. Prospective survey. Toronto, Ont. A total of 338 consecutive, nonemergent patients before consultation with a single spine surgeon over a 5-month period. Patient concerns, effect of referral to a spine surgeon, and effect of waiting to see a spine surgeon. The issues patients reported to be most concerning were ongoing pain (45.6% rated this as most concerning), loss of function (23.4%), need for surgery (12.1%), and permanence of the condition (9.6%). Regression analysis demonstrated that older age was an independent predictor of increased level of concern regarding pain (P=.01) and disability (P=.04). Forty-seven percent of all patients listed the need for surgery among their top 3 concerns. Mere referral to a spine surgeon (P=.03) was an independent predictor of increased concern regarding the need for surgery. Sex, diagnosis, surgical candidacy, and actual wait time were not predictive of increased concerns. Patients reported family physicians to be their most influential information source regarding spinal conditions. Timely provision of more specific information regarding the benign and non-surgical nature of most degenerative spinal conditions might substantially reduce patients' exaggerated concerns regarding the probability of surgery for a considerable number of patients referred to spine surgeons.

  12. Mycobacterium tuberculosis lipoproteins in virulence and immunity - fighting with a double-edged sword.

    PubMed

    Becker, Katja; Sander, Peter

    2016-11-01

    Bacterial lipoproteins are secreted membrane-anchored proteins characterized by a lipobox motif. This lipobox motif directs post-translational modifications at the conserved cysteine through the consecutive action of three enzymes: Lgt, LspA and Lnt, which results in di- or triacylated forms. Lipoproteins are abundant in all bacteria including Mycobacterium tuberculosis and often involved in virulence and immunoregulatory processes. On the one hand, disruption of the biosynthesis pathway of lipoproteins leads to attenuation of M. tuberculosis in vivo, and mycobacteria deficient for certain lipoproteins have been assessed as attenuated live vaccine candidates. On the other hand, several mycobacterial lipoproteins form immunodominant antigens which promote an immune response. Some of these have been explored in DNA or subunit vaccination approaches against tuberculosis. The immune recognition of specific lipoproteins, however, might also benefit long-term survival of M. tuberculosis through immune modulation, while others induce protective responses. Exploiting lipoproteins as vaccines is thus a complex matter which requires deliberative investigation. The dual role of lipoproteins in the immunity to and pathogenicity of mycobacteria is discussed here. © 2016 Federation of European Biochemical Societies.

  13. Targeting GSK-3 family members in the heart: a very sharp double-edged sword.

    PubMed

    Cheng, Hui; Woodgett, James; Maamari, Mia; Force, Thomas

    2011-10-01

    The GSK-3 family of serine/threonine kinases, which is comprised of two isoforms (α and β), was initially identified as a negative regulator of glycogen synthase, the rate limiting enzyme of glycogen synthesis [1,2]. In the 30 years since its initial discovery, the family has been reported to regulate a host of additional cellular processes and, consequently, disease states such as bipolar disorders, diabetes, inflammatory diseases, cancer, and neurodegenerative diseases including Alzheimer's Disease and Parkinson's Disease [3,4]. As a result, there has been intense interest on the part of the pharmaceutical industry in developing small molecule antagonists of GSK-3. Herein, we will review the roles played by GSK-3s in the heart, focusing primarily on recent studies that have employed global and tissue-specific gene deletion. We will highlight roles in various pathologic processes, including pressure overload and ischemic injury, focusing on some striking isoform-specific effects of the family. Due to space limitations and/or the relatively limited data in gene-targeted mice, we will not be addressing the family's roles in ischemic pre-conditioning or its many interactions with various pro- and anti-apoptotic factors. This article is part of a special issue entitled "Key Signaling Molecules in Hypertrophy and Heart Failure." Copyright © 2010 Elsevier Ltd. All rights reserved.

  14. A Double-Edged Sword: Volatile Anesthetic Effects on the Neonatal Brain

    PubMed Central

    Chiao, Sunny; Zuo, Zhiyi

    2014-01-01

    The use of volatile anesthetics, a group of general anesthetics, is an exceedingly common practice. These anesthetics may have neuroprotective effects. Over the last decade, anesthetic induced neurotoxicity in pediatric populations has gained a certain notoriety based on pre-clinical cell and animal studies demonstrating that general anesthetics may induce neurotoxicity, including neuroapoptosis, neurodegeneration, and long-term neurocognitive and behavioral deficits. With hundreds of millions of people having surgery under general anesthesia worldwide, and roughly six million children annually in the U.S. alone, the importance of clearly defining toxic or protective effects of general anesthetics cannot be overstated. Yet, with our expanding body of knowledge, we have come to learn that perhaps not all volatile anesthetics have the same pharmacological profiles; certain ones may have a more favorable neurotoxic profile and may actually exhibit neuroprotection in specific populations and situations. Thus far, very few clinical studies exist, and have not yet been convincing enough to alter our practice. This review will provide an update on current data regarding volatile anesthetic induced neurotoxicity and neuroprotection in neonatal and infant populations. In addition, this paper will discuss ongoing studies and the trajectory of further research over the coming years. PMID:24961761

  15. Neutrophil extracellular traps (NETs): Double-edged swords of innate immunity1

    PubMed Central

    Kaplan, Mariana J.; Radic, Marko

    2012-01-01

    Spectacular images of neutrophils ejecting nuclear chromatin and bactericidal proteins, in response to microbes, were first reported in 2004. As externalized chromatin could entangle bacteria, these structures were named neutrophil extracellular traps (NETs). Subsequent studies identified microorganisms and sterile conditions that stimulate NETs, and additional cell types that release extracellular chromatin. NETs’ release is the most dramatic stage in a cell death process called NETosis. Experimental evidence suggests that NETs participate in pathogenesis of autoimmune and inflammatory disorders, with proposed involvement in glomerulonephritis, chronic lung disease, sepsis and vascular disorders. Exaggerated NETosis or diminished NET clearance likely increases risk of autoreactivity to NET components. The biological significance of NETs is just beginning to be explored. A more complete integration of NETosis within immunology and pathophysiology will require better understanding of NET properties associated with specific disease states and microbial infections. This may lead to the identification of important therapeutic targets. PMID:22956760

  16. A double-edged sword: Benefits and pitfalls of heterogeneous punishment in evolutionary inspection games.

    PubMed

    Perc, Matjaž; Szolnoki, Attila

    2015-06-05

    As a simple model for criminal behavior, the traditional two-strategy inspection game yields counterintuitive results that fail to describe empirical data. The latter shows that crime is often recurrent, and that crime rates do not respond linearly to mitigation attempts. A more apt model entails ordinary people who neither commit nor sanction crime as the third strategy besides the criminals and punishers. Since ordinary people free-ride on the sanctioning efforts of punishers, they may introduce cyclic dominance that enables the coexistence of all three competing strategies. In this setup ordinary individuals become the biggest impediment to crime abatement. We therefore also consider heterogeneous punisher strategies, which seek to reduce their investment into fighting crime in order to attain a more competitive payoff. We show that this diversity of punishment leads to an explosion of complexity in the system, where the benefits and pitfalls of criminal behavior are revealed in the most unexpected ways. Due to the raise and fall of different alliances no less than six consecutive phase transitions occur in dependence on solely the temptation to succumb to criminal behavior, leading the population from ordinary people-dominated across punisher-dominated to crime-dominated phases, yet always failing to abolish crime completely.

  17. Damage-associated molecular patterns in cancer: A double-edged sword

    PubMed Central

    Hernandez, Celine; Huebener, Peter; Schwabe, Robert F.

    2016-01-01

    Damage-associated molecular patterns (DAMPs) are released in response to cell death and stress, and are potent triggers of sterile inflammation. Recent evidence suggests that DAMPs may also have a key role in the development of cancer as well as in the host response to cytotoxic anti-tumor therapy. As such, DAMPs may exert protective functions by alerting the immune system to the presence of dying tumor cells, thereby triggering immunogenic tumor cell death. On the other hand, cell death and release of DAMPs may also trigger chronic inflammation and thereby promote the development or progression of tumors. Here, we will review the contribution of candidate DAMPs and their receptors and discuss the evidence for DAMPs as tumor-promoting and anti-tumor effectors as well as unsolved questions such as DAMP release from non-tumor cells as well as the existence of tumor-specific DAMPs. PMID:27086930

  18. The Double-Edged Sword of Prostate Cancer: 14-3-3(sigma)

    DTIC Science & Technology

    2005-12-01

    in pancreatic ductal adenocarcinoma and colorectal cancers and that the increased 14-3-3σ expression is an independent prognostic marker for poor...survival of these cancer patients (6-10), suggesting that the patients who have higher level of 14-3-3σ in their pancreatic and colorectal caners...the disease and eventual failure of chemotherapy. Indeed, it has been found that 14-3-3σ expression is increased in the drug resistant pancreatic

  19. A double-edged sword: the world according to Capicua in cancer.

    PubMed

    Tanaka, Miwa; Yoshimoto, Toyoki; Nakamura, Takuro

    2017-10-06

    CIC/Capicua is a HMG-box transcription factor that is well conserved during evolution. CIC recognizes the T(G/C)AATG(A/G)A sequence and represses its target genes such as PEA3 family genes. The RTK/RAS/MAPK signals downregulate CIC and relieves CIC's target genes from the transrepressional activity, and CIC thus acts as an important downstream molecule of the pathway and as a tumor suppressor. CIC loss-of-function mutations are frequently observed in several human neoplasms such as oligodendroglioma, and lung and gastric carcinoma. CIC is also involved in chromosomal translocation-associated gene fusions in highly aggressive small round cell sarcoma that is biologically and clinically distinct from Ewing sarcoma. In these mutations, PEA3 family genes and other important target genes are upregulated, inducing malignant phenotypes. Downregulation of CIC abrogates the effect of MAPK inhibitors, suggesting its potential role as an important modifier of molecular target therapies for cancer. These data reveal the importance of CIC as a key molecule in signal transduction, carcinogenesis and developing novel therapies. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  20. Temperate Bacterial Viruses as Double-Edged Swords in Bacterial Warfare

    PubMed Central

    Gama, João Alves; Reis, Ana Maria; Domingues, Iolanda; Mendes-Soares, Helena; Matos, Ana Margarida; Dionisio, Francisco

    2013-01-01

    It has been argued that bacterial cells may use their temperate viruses as biological weapons. For instance, a few bacterial cells among a population of lysogenic cells could release the virus and kill susceptible non-lysogenic competitors, while their clone mates would be immune. Because viruses replicate inside their victims upon infection, this process would amplify their number in the arena. Sometimes, however, temperate viruses spare recipient cells from death by establishing themselves in a dormant state inside cells. This phenomenon is called lysogenization and, for some viruses such as the λ virus, the probability of lysogenization increases with the multiplicity of infection. Therefore, the amplification of viruses leads to conflicting predictions about the efficacy of temperate viruses as biological weapons: amplification can increase the relative advantage of clone mates of lysogens but also the likelihood of saving susceptible cells from death, because the probability of lysogenization is higher. To test the usefulness of viruses as biological weapons, we performed competition experiments between lysogenic Escherichia coli cells carrying the λ virus and susceptible λ-free E. coli cells, either in a structured or unstructured habitat. In structured and sometimes in unstructured habitats, the λ virus qualitatively behaved as a “replicating toxin”. However, such toxic effect of λ viruses ceased after a few days of competition. This was due to the fact that many of initially susceptible cells became lysogenic. Massive lysogenization of susceptible cells occurred precisely under the conditions where the amplification of the virus was substantial. From then on, these cells and their descendants became immune to the λ virus. In conclusion, if at short term bacterial cells may use temperate viruses as biological weapons, after a few days only the classical view of temperate bacterial viruses as parasitic agents prevails. PMID:23536852

  1. Reading "the Word and the World": The Double-Edged Sword of Teaching Critical Literacy

    ERIC Educational Resources Information Center

    White, John Wesley

    2009-01-01

    White acknowledges that critical literacy is central to literacy instruction today, but warns that asking those untrained in critical literacy to "teach" critical literacy could have undesirable consequences. He suggests three potentially undesirable outcomes and offers advice for preventing them.

  2. Alendronate, a double-edged sword acting in the mevalonate pathway

    PubMed Central

    TRICARICO, PAOLA MAURA; GIRARDELLI, MARTINA; KLEINER, GIULIO; KNOWLES, ALESSANDRA; VALENCIC, ERICA; CROVELLA, SERGIO; MARCUZZI, ANNALISA

    2015-01-01

    Aminobisphosphonate aledronate is a compound commonly used clinically for the treatment of osteoporosis and other bone diseases, as a result of it preventing bone resorption. However, in previous years it has also been used to obtain cellular and animal models of a rare genetic disorder termed Mevalonate Kinase Deficiency (MKD). MKD is caused by mutations affecting the mevalonate kinase enzyme, in the cholesterol pathway and alendronate can be used to biochemically mimic the genetic defect as it inhibits farnesyl pyrophosphate synthase in the same pathway. Despite evidence in favor of the inhibition exerted on the mevalonate pathway, there is at least one clinical case of MKD in which alendronate improved not only skeletal and bone fractures, as expected, but also MKD clinical features. Based on this finding, the present study assessed the anti-inflammatory properties of this aminobisphosphonate in vitro. No anti-inflammatory effects of alendronate were observed in the in vitro experiments. Since MKD lacks specific treatments, these results may assist scientists and physicians in making the decision as to the most suitable choice of therapeutic compounds for this neglected disease. PMID:26096667

  3. Alendronate, a double-edged sword acting in the mevalonate pathway.

    PubMed

    Tricarico, Paola Maura; Girardelli, Martina; Kleiner, Giulio; Knowles, Alessandra; Valencic, Erica; Crovella, Sergio; Marcuzzi, Annalisa

    2015-09-01

    Aminobisphosphonate aledronate is a compound commonly used clinically for the treatment of osteoporosis and other bone diseases, as a result of it preventing bone resorption. However, in previous years it has also been used to obtain cellular and animal models of a rare genetic disorder termed Mevalonate Kinase Deficiency (MKD). MKD is caused by mutations affecting the mevalonate kinase enzyme, in the cholesterol pathway and alendronate can be used to biochemically mimic the genetic defect as it inhibits farnesyl pyrophosphate synthase in the same pathway. Despite evidence in favor of the inhibition exerted on the mevalonate pathway, there is at least one clinical case of MKD in which alendronate improved not only skeletal and bone fractures, as expected, but also MKD clinical features. Based on this finding, the present study assessed the anti‑inflammatory properties of this aminobisphosphonate in vitro. No anti‑inflammatory effects of alendronate were observed in the in vitro experiments. Since MKD lacks specific treatments, these results may assist scientists and physicians in making the decision as to the most suitable choice of therapeutic compounds for this neglected disease.

  4. IFNγ-producing CD4(+) T lymphocytes: the double-edged swords in tuberculosis.

    PubMed

    Kumar, Pawan

    2017-12-01

    IFNγ-producing CD4(+) T cells (IFNγ(+)CD4(+) T cells) are the key orchestrators of protective immunity against Mycobacterium tuberculosis (Mtb). Primarily, these cells act by enabling Mtb-infected macrophages to enforce phagosome-lysosome fusion, produce reactive nitrogen intermediates (RNIs), and activate autophagy pathways. However, TB is a heterogeneous disease and a host of clinical and experimental findings has also implicated IFNγ(+)CD4(+) T cells in TB pathogenesis. High frequency of IFNγ(+)CD4(+) T cells is the most invariable feature of the active disease. Active TB patients mount a heightened IFNγ(+)CD4(+) T cell response to mycobacterial antigens and demonstrate an IFNγ-inducible transcriptomic signature. IFNγ(+)CD4(+) T cells have also been shown to mediate TB-associated immune reconstitution inflammatory syndrome (TB-IRIS) observed in a subset of antiretroviral therapy (ART)-treated HIV- and Mtb-coinfected people. The pathological face of IFNγ(+)CD4(+) T cells during mycobacterial infection is further uncovered by studies in the animal model of TB-IRIS and in Mtb-infected PD-1(-/-) mice. This manuscript encompasses the evidence supporting the dual role of IFNγ(+)CD4(+) T cells during Mtb infection and sheds light on immune mechanisms involved in protection versus pathogenesis.

  5. Detail of double pole utility tower at the edge of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of double pole utility tower at the edge of the mesa. National Old Trails Road right-of-way crosses in foreground over a dry laid basaltic rock retaining wall. View south. - La Bajada Historic Trails and Roads, Approximately 1 mile East/Northeast of intersection of State Highway 16 and Indian Service Road 841, La Bajada, Santa Fe County, NM

  6. Space Cadre, the Warfighter’s ’Samurai Sword

    DTIC Science & Technology

    2010-01-01

    samurai sword. It might be interesting to think of the approximately 2,500 space warriors as the “ samurai swords” of the Army bringing their own...Cadre as one would a samurai sword so that the Cadre remains relevant and keeps its sharp edge. Space Cadre, the Warfighter’s “ Samurai Sword...REPORT TYPE 3. DATES COVERED 00-00-2010 to 00-00-2010 4. TITLE AND SUBTITLE Space Cadre, the Warfighter’s ’ Samurai Sword’ 5a. CONTRACT NUMBER

  7. Infrared Spotlight on Orion Sword

    NASA Image and Video Library

    2006-08-15

    This image composite outlines the region near Orion sword that was surveyed by NASA Spitzer Space Telescope white box. The Orion nebula, our closest massive star-making factory, is the brightest spot near the hunter sword.

  8. Can We Afford These Affordances? GarageBand and the Double-Edged Sword of the Digital Audio Workstation

    ERIC Educational Resources Information Center

    Bell, Adam Patrick

    2015-01-01

    The proliferation of computers, tablets, and smartphones has resulted in digital audio workstations (DAWs) such as GarageBand in being some of the most widely distributed musical instruments. Positing that software designers are dictating the music education of DAW-dependent music-makers, I examine the fallacy that music-making applications such…

  9. Is pycnogenol a double-edged sword? Cataractogenic in vitro, but reduces cataract risk in diabetic rats.

    PubMed

    Trevithick, John R; Bantseev, Vladimir; Hirst, Maurice; Dzialoszynski, Tomasz M; Sanford, Ernest S

    2013-07-01

    Pycnogenol was used (a) to study its antioxidant activity, (b) to study its effects on lens integrity in organ culture and (c) in vivo to determine whether it could reduce the damage in model diabetic cataract. For (a) our luminescent antioxidant assay was used, (b) lenses were incubated in medium 199, with 55.6 mM glucose. Lenses were stained with 0.014 mM rhodamine 123 for 15 min to stain mitochondria, immobilized in 1% agarose in M199, and the equatorial region examined by a Zeiss confocal microscope. For (c) cataract grades of streptozotocin diabetic rats fed 1% pycnogenol were followed for 12 weeks. (a) Pycnogenol in vitro was an antioxidant when challenged with peroxide. (b) In vitro, when [570 mg/L] pycnogenol in dimethyl sulfoxide (DMSO) was used, lenses turned opaque after 3 d of incubation, in both pycnogenol controls and glucose + pycnogenol. Normal controls (DMSO, n = 4) and controls (n = 4) remained clear after 8 d of incubation. After 3 d of incubation with pycnogenol, cumulative protein leakage was greater than 0.28 mg/mL versus 8 d controls (0.018 mg/mL). Similar damage occurred at pycnogenol concentrations as low as 20 mg/L. The 20 mg/L pycnogenol control showed mitochondrial death, and calcium concentration in the lens equatorial differentiating fiber cells increased. (c) In vivo feeding pycnogenol resulted in similar growth and body condition for diabetic rats, and lower cataract grades at 9 and 11 weeks: final serum glucose levels were not significantly different, but glycohemoglobin A1 levels were significantly lower (83.9% of normal, p < 0.05) in pycnogenol-fed diabetic rats. Although it appears that pycnogenol has a potential toxic effect on incubated lenses, it appears in vivo to have a marginal protective effect, and also significantly reduces glycation of proteins. Supported by Cognis US (formerly Henkel Chemical Co.) and Horphag Research.

  10. The Double-Edged Sword in Pathogenic Trypanosomatids: The Pivotal Role of Mitochondria in Oxidative Stress and Bioenergetics

    PubMed Central

    Menna-Barreto, Rubem Figueiredo Sadok; de Castro, Solange Lisboa

    2014-01-01

    The pathogenic trypanosomatids Trypanosoma brucei, Trypanosoma cruzi, and Leishmania spp. are the causative agents of African trypanosomiasis, Chagas disease, and leishmaniasis, respectively. These diseases are considered to be neglected tropical illnesses that persist under conditions of poverty and are concentrated in impoverished populations in the developing world. Novel efficient and nontoxic drugs are urgently needed as substitutes for the currently limited chemotherapy. Trypanosomatids display a single mitochondrion with several peculiar features, such as the presence of different energetic and antioxidant enzymes and a specific arrangement of mitochondrial DNA (kinetoplast DNA). Due to mitochondrial differences between mammals and trypanosomatids, this organelle is an excellent candidate for drug intervention. Additionally, during trypanosomatids' life cycle, the shape and functional plasticity of their single mitochondrion undergo profound alterations, reflecting adaptation to different environments. In an uncoupling situation, the organelle produces high amounts of reactive oxygen species. However, these species role in parasite biology is still controversial, involving parasite death, cell signalling, or even proliferation. Novel perspectives on trypanosomatid-targeting chemotherapy could be developed based on better comprehension of mitochondrial oxidative regulation processes. PMID:24800243

  11. Can We Afford These Affordances? GarageBand and the Double-Edged Sword of the Digital Audio Workstation

    ERIC Educational Resources Information Center

    Bell, Adam Patrick

    2015-01-01

    The proliferation of computers, tablets, and smartphones has resulted in digital audio workstations (DAWs) such as GarageBand in being some of the most widely distributed musical instruments. Positing that software designers are dictating the music education of DAW-dependent music-makers, I examine the fallacy that music-making applications such…

  12. Antithymocyte globulins in renal transplantation-from lymphocyte depletion to lymphocyte activation: The doubled-edged sword.

    PubMed

    Bamoulid, Jamal; Crépin, Thomas; Courivaud, Cécile; Rebibou, Jean-Michel; Saas, Philippe; Ducloux, Didier

    2017-07-01

    Compelling data suggest that lymphocyte depletion following T cell depleting therapy may induce prolonged CD4 T cell lymphopenia and trigger lymphocyte activation in some patients. These profound and non-reversible immune changes in T cell pool subsets are the consequence of both impaired thymic renewal and peripheral homeostatic proliferation. Chronic viral challenges by CMV play a major role in these immune alterations. Even when the consequences of CD4 T cell lymphopenia have been now well described, recent studies shed new light on the clinical consequences of immune activation. In this review, we will first focus on the mechanisms involved in T cell pool reconstitution after T cell depletion and further consider the clinical consequences of ATG-induced T cell activation and senescence in renal transplant recipients. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. The Role of the Immune Response in Chlamydia trachomatis Infection of the Male Genital Tract: A Double-Edged Sword

    PubMed Central

    Redgrove, Kate A.; McLaughlin, Eileen A.

    2014-01-01

    Chlamydia trachomatis (CT) is the most prevalent bacterial sexually transmitted infection in the world, with more than 100 million cases reported annually. While there have been extensive studies into the adverse effects that CT infection has on the female genital tract, and on the subsequent ability of these women to conceive, studies into the consequences on male fertility have been limited and controversial. This is in part due to the asymptomatic nature of the infection, where it is estimated that 50% of men with Chlamydia fail to show any symptoms. It is accepted, however, that acute and/or persistent CT infection is the causative agent for conditions such as urethritis, epididymitis, epididymo-orchitis, and potentially prostatitis. As with most infections, the immune system plays a fundamental role in the body’s attempts to eradicate the infection. The first and most important immune response to Chlamydia infection is a local one, whereby immune cells such as leukocytes are recruited to the site of infections, and subsequently secrete pro-inflammatory cytokines and chemokines such as interferon gamma. Immune cells also work to initiate and potentiate chronic inflammation through the production of reactive oxygen species (ROS), and the release of molecules with degradative properties including defensins, elastase, collagenase, cathespins, and lysozyme. This long-term inflammation can lead to cell proliferation (a possible precursor to cancer), tissue remodeling, and scarring, as well as being linked to the onset of autoimmune responses in genetically disposed individuals. This review will focus on the ability of the immune system to recognize and clear acute and persistent chlamydial infections in the male genital tract, and on the paradoxical damage that chronic inflammation resulting from the infection can cause on the reproductive health of the individual. PMID:25386180

  14. The double-edged sword: How evolution can make or break a live-attenuated virus vaccine

    PubMed Central

    Hanley, Kathryn A.

    2012-01-01

    Even students who reject evolution are often willing to consider cases in which evolutionary biology contributes to, or undermines, biomedical interventions. Moreover the intersection of evolutionary biology and biomedicine is fascinating in its own right. This review offers an overview of the ways in which evolution has impacted the design and deployment of live-attenuated virus vaccines, with subsections that may be useful as lecture material or as the basis for case studies in classes at a variety of levels. Live- attenuated virus vaccines have been modified in ways that restrain their replication in a host, so that infection (vaccination) produces immunity but not disease. Applied evolution, in the form of serial passage in novel host cells, is a “classical” method to generate live-attenuated viruses. However many live-attenuated vaccines exhibit reversion to virulence through back-mutation of attenuating mutations, compensatory mutations elsewhere in the genome, recombination or reassortment, or changes in quasispecies diversity. Additionally the combination of multiple live-attenuated strains may result in competition or facilitation between individual vaccine viruses, resulting in undesirable increases in virulence or decreases in immunogenicity. Genetic engineering informed by evolutionary thinking has led to a number of novel approaches to generate live-attenuated virus vaccines that contain substantial safeguards against reversion to virulence and that ameliorate interference among multiple vaccine strains. Finally, vaccines have the potential to shape the evolution of their wild type counterparts in counter-productive ways; at the extreme vaccine-driven eradication of a virus may create an empty niche that promotes the emergence of new viral pathogens. PMID:22468165

  15. A double-edged sword: lactation consultants' perceptions of the impact of breast pumps on the practice of breastfeeding.

    PubMed

    Buckley, Kathleen M

    2009-01-01

    This qualitative descriptive study examined the beliefs and experiences of 12 lactation consultants regarding the impact of breast pumps on breastfeeding practices. Interview topics on breast pumps included types and patterns of use, mothers' experiences, and advantages and risks. The lactation consultants reported an increase in the use of breast pumps due to improved marketing, a change in society's view of pumps as a necessity rather than a luxury, and the impact of birthing technology. Reasons given for this increased use were mothers' need to have greater control over the breastfeeding process and to quantify the amount of breastmilk. Concerns were expressed regarding an overdependency on breastfeeding technology by some lactation consultants and mothers.

  16. Hypoxia-induced autophagy in endothelial cells: a double-edged sword in the progression of infantile haemangioma?

    PubMed

    Chen, Gang; Zhang, Wei; Li, Yin-Ping; Ren, Jian-Gang; Xu, Ning; Liu, Hui; Wang, Feng-Qin; Sun, Zhi-Jun; Jia, Jun; Zhao, Yi-Fang

    2013-06-01

    The aim of this study was to investigate the precise role of hypoxia-induced autophagy in endothelial cells, and whether it contributes to the distinctive progression of infantile haemangioma (IH). The endothelial cells (EOMA and HUVECs) were cultured under hypoxic conditions for indicated times (0-72 h). The results showed that short exposure of the endothelial cells to hypoxia resulted in increased cell survival and proliferation, accompanied by occurrence of autophagy. Prolonged hypoxia-induced autophagy, correlating with increased cell death, was also detected afterwards. Correspondingly, autophagy inhibition prevented the enhanced cell survival and proliferation capacity, advanced the occurrence of cell-death in early hypoxic stage, and meanwhile attenuated the ability of prolonged hypoxia in cell-death induction. Moreover, our data demonstrated that the functional transformation of hypoxia-induced autophagy, pro-survival to pro-death, was rigorously regulated by the switch between hypoxia-inducible factor-1α (HIF-1α) and mammalian target of rapamycin (mTOR) pathways. Importantly, we also revealed the activation levels of HIF-1α and mTOR, as well as the autophagy status during the progression of IH. This study unmasks the functional switch between HIF-1α and mTOR in regulating hypoxia-induced autophagy in endothelial cells and, more importantly, indicates its potential role in the progression of IH.

  17. A double-edged sword role for ubiquitin-proteasome system in brain stem cardiovascular regulation during experimental brain death.

    PubMed

    Wu, Carol H Y; Chan, Julie Y H; Chan, Samuel H H; Chang, Alice Y W

    2011-01-01

    Brain stem cardiovascular regulatory dysfunction during brain death is underpinned by an upregulation of nitric oxide synthase II (NOS II) in rostral ventrolateral medulla (RVLM), the origin of a life-and-death signal detected from blood pressure of comatose patients that disappears before brain death ensues. Furthermore, the ubiquitin-proteasome system (UPS) may be involved in the synthesis and degradation of NOS II. We assessed the hypothesis that the UPS participates in brain stem cardiovascular regulation during brain death by engaging in both synthesis and degradation of NOS II in RVLM. In a clinically relevant experimental model of brain death using Sprague-Dawley rats, pretreatment by microinjection into the bilateral RVLM of proteasome inhibitors (lactacystin or proteasome inhibitor II) antagonized the hypotension and reduction in the life-and-death signal elicited by intravenous administration of Escherichia coli lipopolysaccharide (LPS). On the other hand, pretreatment with an inhibitor of ubiquitin-recycling (ubiquitin aldehyde) or ubiquitin C-terminal hydrolase isozyme L1 (UCH-L1) potentiated the elicited hypotension and blunted the prevalence of the life-and-death signal. Real-time polymerase chain reaction, Western blot, electrophoresis mobility shift assay, chromatin immunoprecipitation and co-immunoprecipitation experiments further showed that the proteasome inhibitors antagonized the augmented nuclear presence of NF-κB or binding between NF-κB and nos II promoter and blunted the reduced cytosolic presence of phosphorylated IκB. The already impeded NOS II protein expression by proteasome inhibitor II was further reduced after gene-knockdown of NF-κB in RVLM. In animals pretreated with UCH-L1 inhibitor and died before significant increase in nos II mRNA occurred, NOS II protein expression in RVLM was considerably elevated. We conclude that UPS participates in the defunct and maintained brain stem cardiovascular regulation during experimental brain death by engaging in both synthesis and degradation of NOS II at RVLM. Our results provide information on new therapeutic initiatives against this fatal eventuality.

  18. A Double-Edged Sword Role for Ubiquitin-Proteasome System in Brain Stem Cardiovascular Regulation During Experimental Brain Death

    PubMed Central

    Wu, Carol H. Y.; Chan, Julie Y. H.; Chan, Samuel H. H.; Chang, Alice Y. W.

    2011-01-01

    Background Brain stem cardiovascular regulatory dysfunction during brain death is underpinned by an upregulation of nitric oxide synthase II (NOS II) in rostral ventrolateral medulla (RVLM), the origin of a life-and-death signal detected from blood pressure of comatose patients that disappears before brain death ensues. Furthermore, the ubiquitin-proteasome system (UPS) may be involved in the synthesis and degradation of NOS II. We assessed the hypothesis that the UPS participates in brain stem cardiovascular regulation during brain death by engaging in both synthesis and degradation of NOS II in RVLM. Methodology/Principal Findings In a clinically relevant experimental model of brain death using Sprague-Dawley rats, pretreatment by microinjection into the bilateral RVLM of proteasome inhibitors (lactacystin or proteasome inhibitor II) antagonized the hypotension and reduction in the life-and-death signal elicited by intravenous administration of Escherichia coli lipopolysaccharide (LPS). On the other hand, pretreatment with an inhibitor of ubiquitin-recycling (ubiquitin aldehyde) or ubiquitin C-terminal hydrolase isozyme L1 (UCH-L1) potentiated the elicited hypotension and blunted the prevalence of the life-and-death signal. Real-time polymerase chain reaction, Western blot, electrophoresis mobility shift assay, chromatin immunoprecipitation and co-immunoprecipitation experiments further showed that the proteasome inhibitors antagonized the augmented nuclear presence of NF-κB or binding between NF-κB and nos II promoter and blunted the reduced cytosolic presence of phosphorylated IκB. The already impeded NOS II protein expression by proteasome inhibitor II was further reduced after gene-knockdown of NF-κB in RVLM. In animals pretreated with UCH-L1 inhibitor and died before significant increase in nos II mRNA occurred, NOS II protein expression in RVLM was considerably elevated. Conclusions/Significance We conclude that UPS participates in the defunct and maintained brain stem cardiovascular regulation during experimental brain death by engaging in both synthesis and degradation of NOS II at RVLM. Our results provide information on new therapeutic initiatives against this fatal eventuality. PMID:22110641

  19. Addressing the Antibiotic Resistance Problem with Probiotics: Reducing the Risk of Its Double-Edged Sword Effect

    PubMed Central

    Imperial, Ivan C. V. J.; Ibana, Joyce A.

    2016-01-01

    Antibiotic resistance is a global public health problem that requires our attention. Indiscriminate antibiotic use is a major contributor in the introduction of selective pressures in our natural environments that have significantly contributed in the rapid emergence of antibiotic-resistant microbial strains. The use of probiotics in lieu of antibiotic therapy to address certain health conditions in both animals and humans may alleviate these antibiotic-mediated selective pressures. Probiotic use is defined as the actual application of live beneficial microbes to obtain a desired outcome by preventing diseased state or improving general health. Multiple studies have confirmed the beneficial effects of probiotic use in the health of both livestock and humans. As such, probiotics consumption is gaining popularity worldwide. However, concerns have been raised in the use of some probiotics strains that carry antibiotic resistance genes themselves, as they have the potential to pass the antibiotic resistance genes to pathogenic bacteria through horizontal gene transfer. Therefore, with the current public health concern on antibiotic resistance globally, in this review, we underscore the need to screen probiotic strains that are used in both livestock and human applications to assure their safety and mitigate their potential in significantly contributing to the spread of antibiotic resistance genes in our natural environments. PMID:28018315

  20. The Regulatory Environment in Long Day Care: A "Double-Edged Sword" for Early Childhood Professional Practice

    ERIC Educational Resources Information Center

    Fenech, Marianne; Sumsion, Jennifer; Goodfellow, Joy

    2006-01-01

    While early childhood professionals in NSW are accountable to a substantial collection of regulatory requirements, little research has explored the outcomes of this regulatory environment, both intended and otherwise. This paper presents findings from a NSW study and shows how early childhood professionals working in long day care centres perceive…

  1. A Double-Edged Sword: The Merits and the Policy Implications of Google Translate in Higher Education

    ERIC Educational Resources Information Center

    Mundt, Klaus; Groves, Michael

    2016-01-01

    Machine translation, specifically Google Translate, is freely available, and is improving in its ability to provide grammatically accurate translations. This development has the potential to provoke a major transformation in the internationalization process at universities, since students may be, in the future, able to use technology to circumvent…

  2. Von Willebrand factor in patients on mechanical circulatory support - a double-edged sword between bleeding and thrombosis.

    PubMed

    Hudzik, Bartosz; Kaczmarski, Jacek; Pacholewicz, Jerzy; Zakliczynski, Michal; Gasior, Mariusz; Zembala, Marian

    2015-09-01

    Mechanical circulatory support (MCS) is an umbrella term describing the various technologies used in both short- and long-term management of patients with either end-stage chronic heart failure (HF) or acute HF. Most often, MCS has emerged as a bridge to transplantation, but more recently it is also used as a destination therapy. Mechanical circulatory support includes left ventricular assist device (LVAD) or bi-ventricular assist device (Bi-VAD). Currently, 2- to 3-year survival in carefully selected patients is much better than with medical therapy. However, MCS therapy is hampered by sometimes life-threatening complications including bleeding and device thrombosis. Von Willebrand factor (vWF) has two major functions in haemostasis. First, it plays a crucial role in platelet-subendothelium adhesion and platelet-platelet interactions (aggregation). Second, it is the carrier of factor VIII (FVIII) in plasma. Von Willebrand factor prolongs FVIII half-time by protecting it from proteolytic degradation. It delivers FVIII to the site of vascular injury thus enhancing haemostatic process. On one hand, high plasma levels of vWF have been associated with an increased risk of thrombosis. On the other, defects or deficiencies of vWF underlie the inherited von Willebrand disease or acquired von Willebrand syndrome. Here we review the pathophysiology of thrombosis and bleeding associated with vWF.

  3. A Double-Edged Sword: The Merits and the Policy Implications of Google Translate in Higher Education

    ERIC Educational Resources Information Center

    Mundt, Klaus; Groves, Michael

    2016-01-01

    Machine translation, specifically Google Translate, is freely available, and is improving in its ability to provide grammatically accurate translations. This development has the potential to provoke a major transformation in the internationalization process at universities, since students may be, in the future, able to use technology to circumvent…

  4. Unreacted PbI2 as a Double-Edged Sword for Enhancing the Performance of Perovskite Solar Cells.

    PubMed

    Jacobsson, T Jesper; Correa-Baena, Juan-Pablo; Halvani Anaraki, Elham; Philippe, Bertrand; Stranks, Samuel D; Bouduban, Marine E F; Tress, Wolfgang; Schenk, Kurt; Teuscher, Joël; Moser, Jacques-E; Rensmo, Håkan; Hagfeldt, Anders

    2016-08-17

    Lead halide perovskites have over the past few years attracted considerable interest as photo absorbers in PV applications with record efficiencies now reaching 22%. It has recently been found that not only the composition but also the precise stoichiometry is important for the device performance. Recent reports have, for example, demonstrated small amount of PbI2 in the perovskite films to be beneficial for the overall performance of both the standard perovskite, CH3NH3PbI3, as well as for the mixed perovskites (CH3NH3)x(CH(NH2)2)(1-x)PbBryI(3-y). In this work a broad range of characterization techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photo electron spectroscopy (PES), transient absorption spectroscopy (TAS), UV-vis, electroluminescence (EL), photoluminescence (PL), and confocal PL mapping have been used to further understand the importance of remnant PbI2 in perovskite solar cells. Our best devices were over 18% efficient, and had in line with previous results a small amount of excess PbI2. For the PbI2-deficient samples, the photocurrent dropped, which could be attributed to accumulation of organic species at the grain boundaries, low charge carrier mobility, and decreased electron injection into the TiO2. The PbI2-deficient compositions did, however, also have advantages. The record Voc was as high as 1.20 V and was found in PbI2-deficient samples. This was correlated with high crystal quality, longer charge carrier lifetimes, and high PL yields and was rationalized as a consequence of the dynamics of the perovskite formation. We further found the ion migration to be obstructed in the PbI2-deficient samples, which decreased the JV hysteresis and increased the photostability. PbI2-deficient synthesis conditions can thus be used to deposit perovskites with excellent crystal quality but with the downside of grain boundaries enriched in organic species, which act as a barrier toward current transport. Exploring ways to tune the synthesis conditions to give the high crystal quality obtained under PbI2-poor condition while maintaining the favorable grain boundary characteristics obtained under PbI2-rich conditions would thus be a strategy toward more efficiency devices.

  5. Gendered uncertainty and variation in physicians' decisions for coronary heart disease: the double-edged sword of "atypical symptoms".

    PubMed

    Welch, Lisa C; Lutfey, Karen E; Gerstenberger, Eric; Grace, Matthew

    2012-09-01

    Nonmedical factors and diagnostic certainty contribute to variation in clinical decision making, but the process by which this occurs remains unclear. We examine how physicians' interpretations of patient sex-gender affect diagnostic certainty and, in turn, decision making for coronary heart disease. Data are from a factorial experiment of 256 physicians who viewed 1 of 16 video vignettes with different patient-actors presenting the same symptoms of coronary heart disease. Physician participants completed a structured interview and provided a narrative about their decision-making processes. Quantitative analysis showed that diagnostic uncertainty reduces the likelihood that physicians will order tests and medications appropriate for an urgent cardiac condition in particular. Qualitative analysis revealed that a subset of physicians applied knowledge that women have "atypical symptoms" as a generalization, which engendered uncertainty for some. Findings are discussed in relation to social-psychological processes that underlie clinical decision making and the social framing of medical knowledge.

  6. Gendered Uncertainty and Variation in Physicians' Decisions for Coronary Heart Disease: The Double-Edged Sword of "Atypical Symptoms"

    ERIC Educational Resources Information Center

    Welch, Lisa C.; Lutfey, Karen E.; Gerstenberger, Eric; Grace, Matthew

    2012-01-01

    Nonmedical factors and diagnostic certainty contribute to variation in clinical decision making, but the process by which this occurs remains unclear. We examine how physicians' interpretations of patient sex-gender affect diagnostic certainty and, in turn, decision making for coronary heart disease. Data are from a factorial experiment of 256…

  7. Gendered Uncertainty and Variation in Physicians' Decisions for Coronary Heart Disease: The Double-Edged Sword of "Atypical Symptoms"

    ERIC Educational Resources Information Center

    Welch, Lisa C.; Lutfey, Karen E.; Gerstenberger, Eric; Grace, Matthew

    2012-01-01

    Nonmedical factors and diagnostic certainty contribute to variation in clinical decision making, but the process by which this occurs remains unclear. We examine how physicians' interpretations of patient sex-gender affect diagnostic certainty and, in turn, decision making for coronary heart disease. Data are from a factorial experiment of 256…

  8. Social Network as Double-Edged Sword to Exchange: Frictions and the Emerging of Intellectual Intermediary Service

    NASA Astrophysics Data System (ADS)

    Li, Li; Wu, Bangtao; Chen, Zhong; Zhao, Liangjie

    The value of complex social network and the optimization of it are determined by the structure and nodes’ characteristics. Direct friction and indirect friction are defined to describe the possible exchange difficulty each node meets with its neighbors in exchange network. Exogenous intermediary and endogenous intermediary can decrease these frictions by adding links. Agent-based Simulating results show that both frictions and the optimization of them are influenced by demander and supplier rate, the exchange network structure as well as the environment constrains and exogenous intermediation acts better than endogenous intermediation in decreasing both frictions. While assists exchange, the results of this paper also implies social network as origin of impefect market.

  9. A double-edged sword: does highly active antiretroviral therapy contribute to syphilis incidence by impairing immunity to Treponema pallidum?

    PubMed

    Rekart, Michael L; Ndifon, Wilfred; Brunham, Robert C; Dushoff, Jonathan; Park, Sang Woo; Rawat, Sanjana; Cameron, Caroline E

    2017-08-01

    Recently, the world has experienced a rapidly escalating outbreak of infectious syphilis primarily affecting men who have sex with men (MSM); many are taking highly active antiretroviral therapy (HAART) for HIV-1 infection. The prevailing hypothesis is that HAART availability and effectiveness have led to the perception among both individuals who are HIV-1 infected and those who are uninfected that HIV-1 transmission has become much less likely, and the effects of HIV-1 infection less deadly. This is expected to result in increased sexual risk-taking, especially unprotected anal intercourse, leading to more non-HIV-1 STDs, including gonorrhoea, chlamydia and syphilis. However, syphilis incidence has increased more rapidly than other STDs. We hypothesise that HAART downregulates the innate and acquired immune responses to Treponema pallidum and that this biological explanation plays an important role in the syphilis epidemic. We performed a literature search and developed a mathematical model of HIV-1 and T. pallidum confection in a population with two risk groups with assortative mixing to explore the consequence on syphilis prevalence of HAART-induced changes in behaviour versus HAART-induced biological effects. Since rising syphilis incidence appears to have outpaced gonorrhoea and chlamydia, predominantly affecting HIV-1 positive MSM, behavioural factors alone may be insufficient to explain the unique, sharp increase in syphilis incidence. HAART agents have the potential to alter the innate and acquired immune responses in ways that may enhance susceptibility to T. pallidum. This raises the possibility that therapeutic and preventative HAART may inadvertently increase the incidence of syphilis, a situation that would have significant and global public health implications. We propose that additional studies investigating the interplay between HAART and enhanced T. pallidum susceptibility are needed. If our hypothesis is correct, HAART should be combined with enhanced patient management including frequent monitoring for pathogens such as T. pallidum. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  10. Double-edged sword of interdisciplinary knowledge flow from hard sciences to humanities and social sciences: Evidence from China.

    PubMed

    Liu, Meijun; Shi, Dongbo; Li, Jiang

    2017-01-01

    Humanities and Social Sciences (HSS) increasingly absorb knowledge from Hard Sciences, i.e., Science, Technology, Agriculture and Medicine (STAM), as testified by a growing number of citations. However, whether citing more Hard Sciences brings more citations to HSS remains to be investigated. Based on China's HSS articles indexed by the Web of Science during 1998-2014, this paper estimated two-way fixed effects negative binomial models, with journal effects and year effects. Findings include: (1) An inverse U-shaped curve was observed between the percentage of STAM references to the HSS articles and the number of citations they received; (2) STAM contributed increasing knowledge to China's HSS, while Science and Technology knowledge contributed more citations to HSS articles. It is recommended that research policy should be adjusted to encourage HSS researchers to adequately integrate STAM knowledge when conducting interdisciplinary research, as over-cited STAM knowledge may jeopardize the readability of HSS articles.

  11. Ovarian Dendritic Cells Act as a Double-Edged Pro-Ovulatory and Anti-Inflammatory Sword

    PubMed Central

    Cohen-Fredarow, Adva; Tadmor, Ari; Raz, Tal; Meterani, Naama; Addadi, Yoseph; Nevo, Nava; Solomonov, Inna; Sagi, Irit; Mor, Gil; Neeman, Michal

    2014-01-01

    Ovulation and inflammation share common attributes, including immune cell invasion into the ovary. The present study aims at deciphering the role of dendritic cells (DCs) in ovulation and corpus luteum formation. Using a CD11c-EYFP transgenic mouse model, ovarian transplantation experiments, and fluorescence-activated cell sorting analyses, we demonstrate that CD11c-positive, F4/80-negative cells, representing DCs, are recruited to the ovary under gonadotropin regulation. By conditional ablation of these cells in CD11c-DTR transgenic mice, we revealed that they are essential for expansion of the cumulus-oocyte complex, release of the ovum from the ovarian follicle, formation of a functional corpus luteum, and enhanced lymphangiogenesis. These experiments were complemented by allogeneic DC transplantation after conditional ablation of CD11c-positive cells that rescued ovulation. The pro-ovulatory effects of these cells were mediated by up-regulation of ovulation-essential genes. Interestingly, we detected a remarkable anti-inflammatory capacity of ovarian DCs, which seemingly serves to restrict the ovulatory-associated inflammation. In addition to discovering the role of DCs in ovulation, this study implies the extended capabilities of these cells, beyond their classic immunologic role, which is relevant also to other biological systems. PMID:24825398

  12. The nociceptive and anti-nociceptive effects of bee venom injection and therapy: A double-edged sword

    PubMed Central

    Chen, Jun; Lariviere, William R.

    2010-01-01

    Bee venom injection as a therapy, like many other complementary and alternative medicine approaches, has been used for thousands of years to attempt to alleviate a range of diseases including arthritis. More recently, additional theraupeutic goals have been added to the list of diseases making this a critical time to evaluate the evidence for the beneficial and adverse effects of bee venom injection. Although reports of pain reduction (analgesic and antinociceptive) and anti-inflammatory effects of bee venom injection are accumulating in the literature, it is common knowledge that bee venom stings are painful and produce inflammation. In addition, a significant number of studies have been performed in the past decade highlighting that injection of bee venom and components of bee venom produce significant signs of pain or nociception, inflammation and many effects at multiple levels of immediate, acute and prolonged pain processes. This report reviews the extensive new data regarding the deleterious effects of bee venom injection in people and animals, our current understanding of the responsible underlying mechanisms and critical venom components, and provides a critical evaluation of reports of the beneficial effects of bee venom injection in people and animals and the proposed underlying mechanisms. Although further studies are required to make firm conclusions, therapeutic bee venom injection may be beneficial for some patients, but may also be harmful. This report highlights key patterns of results, critical shortcomings, and essential areas requiring further study. PMID:20558236

  13. Clinical life: expectation and the double edge of medical promise.

    PubMed

    Shim, Janet K; Russ, Ann J; Kaufman, Sharon R

    2007-04-01

    This article introduces the concept of clinical life to capture a form of life produced in the pursuit and wake of medically achieved longevity. Relying on the retrospective accounts of 28 individuals over age 70 who have undergone cardiac bypass surgery, angioplasty or a stent procedure, as well as interviews with their families and with clinicians, we examine three features of clinical life. First, patients do not distinguish between clinical possibility and clinical promise, and thus assume that life can and will be improved by medical intervention in late life. Rather than anticipating a range of potential treatment outcomes, patients therefore expect the best-case scenario: that medical procedures will reverse aging, disease and the march of time. Second, patients then assess the value of their post-procedure lives in accordance with that expectation. Norms regarding what life 'should be like' at particular ages are continually recalibrated to the horizon of what is clinically possible. And third, the price of living longer entails a double-edged relationship with the clinic--it generates opportunities for bodily restoration and increased self-worth but also creates ambivalence about the value of life. This latter feature of clinical life is rarely publicly acknowledged in an environment that emphasizes medical promise.

  14. Optimal Shape of a Gamma-ray Collimator: single vs double knife edge

    NASA Astrophysics Data System (ADS)

    Metz, Albert; Hogenbirk, Alfred

    2017-09-01

    Gamma-ray collimators in nuclear waste scanners are used for selecting a narrow vertical segment in activity measurements of waste vessels. The system that is used by NRG uses tapered slit collimators of both the single and double knife edge type. The properties of these collimators were investigated by means of Monte Carlo simulations. We found that single knife edge collimators are highly preferable for a conservative estimate of the activity of the waste vessels. These collimators show much less dependence on the angle of incidence of the radiation than double knife edge collimators. This conclusion also applies to cylindrical collimators of the single knife edge type, that are generally used in medical imaging spectroscopy.

  15. In-line digital holography with double knife edge

    NASA Astrophysics Data System (ADS)

    Ramirez, Claudio; Iemmi, Claudio; Campos, Juan

    2015-06-01

    We study and test a new technique for in-line digital holography which avoids the formation of the conjugate images. Inline digital holography is based in a common path configuration. In this case, the hologram is produced by the interference between the reference wave front and the diffracted wave front by an almost transparent object. Twin images are obtained with obscured rings that difficult the determination of the best focusing plane. To avoid the conjugated image, the information of the magnitude and phase of the wave front are needed. In a recent work a new in-line digital holography technique was proposed. In this method the object is illuminated with a collimated wave front. A plane, close to the particles distribution is imaged onto a CCD by means of a convergent lens and at the same time, a knife edge is placed in the focal plane of the lens in order to block half of spatial frequency spectrum. In this way, by means of a numerical processing performed on the Fourier plane, it is possible to eliminate one of the components (real or conjugate) of the reconstructed images nevertheless it is observed a tiny deformation of the resulting hologram image. To compensate this effect, we propose a new configuration in which we implement the knife edge technique on both parts of the spectrum at the same time. Finally in the computer, we process the holograms to build one complete without deformation. This hologram is used to recover the wave front at different planes without the influence of the conjugate image.

  16. Edge effects in vertically-oriented graphene based electric double-layer capacitors

    NASA Astrophysics Data System (ADS)

    Yang, Huachao; Yang, Jinyuan; Bo, Zheng; Zhang, Shuo; Yan, Jianhua; Cen, Kefa

    2016-08-01

    Vertically-oriented graphenes (VGs) have been demonstrated as a promising active material for electric double-layer capacitors (EDLCs), partially due to their edge-enriched structure. In this work, the 'edge effects', i.e., edges as the promoters of high capacitance, in VG based EDLCs are investigated with experimental research and numerical simulations. VGs with diverse heights (i.e., edge-to-basal ratios) and edge densities are prepared with varying the plasma-enabled growth time and employing different plasma sources. Electrochemical measurements show that the edges play a predominant role on the charge storage behavior of VGs. A simulation is further conducted to unveil the roles of the edges on the separation and adsorption of ions within VG channels. The initial charge distribution of a VG plane is obtained with density functional theory (DFT) calculations, which is subsequently applied to a molecular dynamics (MD) simulation system to gain the insights into the microscope EDLC structures. Compared with the basal planes, the edges present higher initial charge density (by 4.2 times), higher ion packing density (by 2.6 times), closer ion packing location (by 0.8 Å), and larger ion separation degree (by 14%). The as-obtained findings will be instructive in designing the morphology and structure of VGs for enhanced capacitive performances.

  17. Doppler Lidar Measurements of Tropospheric Wind Profiles Using the Aerosol Double Edge Technique

    NASA Technical Reports Server (NTRS)

    Gentry, Bruce M.; Li, Steven X.; Mathur, Savyasachee; Korb, C. Laurence; Chen, Huailin

    2000-01-01

    The development of a ground based direct detection Doppler lidar based on the recently described aerosol double edge technique is reported. A pulsed, injection seeded Nd:YAG laser operating at 1064 nm is used to make range resolved measurements of atmospheric winds in the free troposphere. The wind measurements are determined by measuring the Doppler shift of the laser signal backscattered from atmospheric aerosols. The lidar instrument and double edge method are described and initial tropospheric wind profile measurements are presented. Wind profiles are reported for both day and night operation. The measurements extend to altitudes as high as 14 km and are compared to rawinsonde wind profile data from Dulles airport in Virginia. Vertical resolution of the lidar measurements is 330 m and the rms precision of the measurements is a low as 0.6 m/s.

  18. Stress intensity factors of double edge cracks in large groove plates under mode I tension

    NASA Astrophysics Data System (ADS)

    Ismail, A. E.; Azlan, M. A.; Tobi, M. L. M.; Ahmad, M. H.

    2016-10-01

    The solutions of stress intensity factors (SIFs) of double edge cracks in large groove plates are investigated. The plate is assumed to fulfil the plain strain condition and it is axially stressed. According to the literature, the SIFs of the cracks in circular notches are available. However, the roles of cracks in large groove are difficult to obtain. Therefore, different grooves and crack geometries are modelled numerically using the ANSYS finite element software. The present model is first validated using an existing model of double edge cracks without notches and it is found that both models are in close agreement. The large grooves are then introduced and the cracks are positioned in the mid-point. It is found numerically that the SIFs are strongly affected by the relative crack depth and the groove geometries. It is also found that the large groove is capable of reducing the SIFs in comparison with the circular notched due to lower stress concentration factors.

  19. Asynchronous Periodic Edge-Event Triggered Control for Double-Integrator Networks With Communication Time Delays.

    PubMed

    Duan, Gaopeng; Xiao, Feng; Wang, Long

    2017-01-23

    This paper focuses on the average consensus of double-integrator networked systems based on the asynchronous periodic edge-event triggered control. The asynchronous property lies in the edge event-detecting procedure. For different edges, their event detections are performed at different times and the corresponding events occur independently of each other. When an event is activated, the two adjacent agents connected by the corresponding link sample their relative state information and update their controllers. The application of incidence matrix facilitates the transformation of control objects from the agent-based to the edge-based. Practically, due to the constraints of network bandwidth and communication distance, agents usually cannot receive the instantaneous information of some others, which has an impact on the system performance. Hence, it is necessary to investigate the presence of communication time delays. For double-integrator multiagent systems with and without communication time delays, the average state consensus can be asynchronously achieved by designing appropriate parameters under the proposed event-detecting rules. The presented results specify the relationship among the maximum allowable time delays, interaction topologies, and event-detecting periods. Furthermore, the proposed protocols have the advantages of reduced communication costs and controller-updating costs. Simulation examples are given to illustrate the proposed theoretical results.

  20. Lidar Measurements of Tropospheric Wind Profiles with the Double Edge Technique

    NASA Technical Reports Server (NTRS)

    Gentry, Bruce M.; Li, Steven X.; Korb, C. Laurence; Mathur, Savyasachee; Chen, Huailin

    1998-01-01

    have developed a variation of the edge technique called the double edge technique. In this paper a ground based aerosol double edge lidar is described and the first measurements of wind profiles in the free troposphere obtained with this lidar will be presented.

  1. Double-core ionization and excitation above the sulphur K-edge in ?, ? and ?

    NASA Astrophysics Data System (ADS)

    Reynaud, Cécile; Gaveau, Marc-André; Bisson, Kristel; Millié, Philippe; Nenner, Irène; Bodeur, Suzanne; Archirel, Pierre; Lévy, Bernard

    1996-11-01

    Experimental and theoretical results are reported on double-core excitation and ionization processes in some sulphur containing molecules. X-ray absorption spectra have been recorded at the sulphur K-edge using synchrotron radiation delivered by the DCI ring at LURE (Orsay, France). Absolute x-ray absorption cross sections have been determined for gas phase 0953-4075/29/22/017/img12, 0953-4075/29/22/017/img13 and 0953-4075/29/22/017/img14 molecules in the 2400 - 2800 eV region. Several narrow features are observed far from the edge and assigned to 0953-4075/29/22/017/img15 double-core excited states. Two series of states are present corresponding to the triplet and singlet configurations, due to the core 1s - 2p exchange term. The energy, width and intensity of the features are strongly molecule dependent. In the case of 0953-4075/29/22/017/img12, a theoretical determination of all the single- and double-core vacancy ionization potentials has been performed using a new theoretical approach which makes it possible to solve the convergence problem inherent in a simple SCF calculation. Results compare favourably with available experimental values. In particular, the singlet - triplet separation is correctly predicted for all the double-core ionized states. The relation between the double-core relaxation energies and the associated single-core relaxation values is discussed. Finally, the double-core excited state energies are determined within a Z + 2 core equivalent model, allowing a full assignment of the 0953-4075/29/22/017/img15 experimental spectra of 0953-4075/29/22/017/img12.

  2. A survey of the Saturnian ring edges: Results from double star occultations

    NASA Astrophysics Data System (ADS)

    Albers, Nicole

    2015-11-01

    The Cassini Ultraviolet Imaging Spectrograph (UVIS) High Speed Photometer (HSP) has recorded more than 150 stellar occultations of Saturn's rings. About one third are observations involving double stars, where each star contributes its own, independent light curve. For each light curve, its footprint, as projected into the ring plane and depending on observation geometry, samples a different region in the ring. Here, we focus on ring edges. Each occultation then yields two independent edge measurements at two different times and longitudes. We infer relative changes in optical depth and radial position over an azimuthal distance as short as 20 meters. These relative measurements require neither photometric nor geometric calibration and inform on the small-scale variability of structure/features with relative resolutions an order of magnitude higher than typically achieved.The Encke and Keeler gap edges as well as the outer B and A ring edges show radial excursions on the order of tens of meters. These radial variations are, in comparison to the common multi-mode analysis of edge kinematics, high-frequency components with corresponding m numbers of m>5000000. We note that spatial dimensions inferred here are 10-100 times smaller than those of features Region A and B at the B ring edge or "Peggy"-type objects at the A ring edge, and are comparable to individual self-gravity wakes or clumps/particles. The Titan and Huygens ringlets inner and outer edges, on the other hand, are, in comparison, highly regular and smooth with radial variations of only a few meters. Nevertheless they show changes in normal optical depth on the order of 0.4, well above the expected margin due to intrinsic stellar variability. We also identified three features in the C ring that show little radial variability and can thus be considered smooth. Interestingly, this irregularity or raggedness of the edges - manifestation of intrinsic small-scale structure of the ring - is stronger with

  3. Daniel Shays and Lafayette's Sword.

    ERIC Educational Resources Information Center

    Gross, Robert A.

    1987-01-01

    Reports on the story of Daniel Shays' sale of a sword given to him by General Lafayette. The story was used by Shays' contemporaries as a means of attacking the rebellion. Notes that while Shay died a poor and homeless man, we remember and honor him for devotion to principle and the responsibility he showed toward his neighbors. (JDH)

  4. The Sword of Orion

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] AnimationFigure 1

    This infrared image from NASA's Spitzer Space Telescope shows the Orion nebula, our closest massive star-making factory, 1,450 light-years from Earth. The nebula is close enough to appear to the naked eye as a fuzzy star in the sword of the popular hunter constellation.

    The nebula itself is located on the lower half of the image, surrounded by a ring of dust. It formed in a cold cloud of gas and dust and contains about 1,000 young stars. These stars illuminate the cloud, creating the beautiful nebulosity, or swirls of material, seen here in infrared.

    In the center of the nebula (bottom inset of figure 1) are four monstrously massive stars, up to 100,000 times as luminous as our sun, called the Trapezium (tiny yellow smudge to the lower left of green splotches. Radiation and winds from these stars are blasting gas and dust away, excavating a cavity walled in by the large ring of dust.

    Behind the Trapezium, still buried deeply in the cloud, a second generation of massive stars is forming (in the area with green splotches). The speckled green fuzz in this bright region is created when bullets of gas shoot out from the juvenile stars and ram into the surrounding cloud.

    Above this region of intense activity are networks of cold material that appear as dark veins against the pinkish nebulosity (upper inset pf figure 1). These dark veins contain embryonic stars. Some of the natal stars illuminate the cloud, creating small, aqua-colored wisps. In addition, jets of gas from the stars ram into the cloud, resulting in the green horseshoe-shaped globs.

    Spitzer surveyed a significant swath of the Orion constellation, beyond what is highlighted in this image. Within that region, called the Orion cloud complex, the telescope found 2,300 stars circled by disks of planet-forming dust and 200 stellar embryos too young to have developed

  5. The Sword of Orion

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] AnimationFigure 1

    This infrared image from NASA's Spitzer Space Telescope shows the Orion nebula, our closest massive star-making factory, 1,450 light-years from Earth. The nebula is close enough to appear to the naked eye as a fuzzy star in the sword of the popular hunter constellation.

    The nebula itself is located on the lower half of the image, surrounded by a ring of dust. It formed in a cold cloud of gas and dust and contains about 1,000 young stars. These stars illuminate the cloud, creating the beautiful nebulosity, or swirls of material, seen here in infrared.

    In the center of the nebula (bottom inset of figure 1) are four monstrously massive stars, up to 100,000 times as luminous as our sun, called the Trapezium (tiny yellow smudge to the lower left of green splotches. Radiation and winds from these stars are blasting gas and dust away, excavating a cavity walled in by the large ring of dust.

    Behind the Trapezium, still buried deeply in the cloud, a second generation of massive stars is forming (in the area with green splotches). The speckled green fuzz in this bright region is created when bullets of gas shoot out from the juvenile stars and ram into the surrounding cloud.

    Above this region of intense activity are networks of cold material that appear as dark veins against the pinkish nebulosity (upper inset pf figure 1). These dark veins contain embryonic stars. Some of the natal stars illuminate the cloud, creating small, aqua-colored wisps. In addition, jets of gas from the stars ram into the cloud, resulting in the green horseshoe-shaped globs.

    Spitzer surveyed a significant swath of the Orion constellation, beyond what is highlighted in this image. Within that region, called the Orion cloud complex, the telescope found 2,300 stars circled by disks of planet-forming dust and 200 stellar embryos too young to have developed

  6. The double-edged experience of healthcare encounters among women with endometriosis: A qualitative study.

    PubMed

    Grundström, Hanna; Alehagen, Siw; Kjølhede, Preben; Berterö, Carina

    2017-05-11

    To identify and describe the experience of healthcare encounters among women with endometriosis. Endometriosis is a "hidden" chronic gynaecological disease appearing in every 10th woman of fertile age. Different manifestations of pain are the main symptoms, often leading to impaired physical and mental health, and lower quality of life. Previous research on healthcare experiences among women with endometriosis has focused on diagnostic delay and experiences of encountering general practitioners. A qualitative, interpretive, phenomenological approach was used. We interviewed nine women aged 23-55, with a laparoscopy-confirmed diagnosis of endometriosis. The interviews were recorded and transcribed verbatim. The data were analysed following the steps of the interpretive phenomenological approach. Two themes were identified in the interview transcripts: being treated with ignorance and being acknowledged. The essence: "the double-edged experience of healthcare encounters" emerged from the themes. The women's experience was double-edged as it involved contradictory feelings: the encounters were experienced as both destructive or constructive. On the one hand, the destructive side was characterised by ignorance, exposure and disbelief. On the other hand, the constructive side made the women feel acknowledged and confirmed, boosting their self-esteem. The new and important aspects of the findings are that the experience of healthcare encounters is for the first time expressed as double-edged: both destructive and constructive. The experience was of specific importance as it affected the women's perceptions of themselves and of their bodies. The information about the constructive side of the experience is of clinical valuable for all healthcare professionals (nurses, midwives and doctors) encountering these women, as it provides a new level of understanding of the experiences. The findings demonstrate both psychological and practical aspects that can help professionals to

  7. Simulation of Edge Plasmas in DIII-D Double-Null Configurations

    SciTech Connect

    Rensink, M E; Lasnier, C J; Petrie, T W; Porter, G D; Rognlien, T D

    2001-09-06

    We present fluid model simulation results for the edge plasma in the DIII-D tokamak with unbalanced double-null magnetic configurations, including cross field drifts. Input parameters are typical of low-power operation in DIII-D. For high-recycling the plasma tends to be detached from all divertor plates. Midplane plasma and electric field profiles are relatively insensitive to the magnetic imbalance. Divertor heat flux profiles exhibit sharp peaks due to cross-field drifts when the ion grad-B drift direction is away from the x-point toward the magnetic axis.

  8. Brillouin optical time domain reflectometry for fast detection of dynamic strain incorporating double-edge technique

    NASA Astrophysics Data System (ADS)

    Shangguan, Mingjia; Wang, Chong; Xia, Haiyun; Shentu, Guoliang; Dou, Xiankang; Zhang, Qiang; Pan, Jian-wei

    2017-09-01

    For the first time, to the best of our knowledge, a direct detection Brillouin optical time-domain reflectometry (BOTDR) is demonstrated for fast distributed dynamic strain sensing incorporating double-edge technique, time-division multiplexing technique and upconversion technique. In order to guarantee the robust stability of the system, the double-edge technique is implemented by using a convert single-channel FPI and a fiber-coupled upconversion single-photon detector, incorporating a time-division multiplexing method. The upconversion single-photon detector is adopted to upconvert the backscattering photons from 1548.1 nm to 863 nm, which is subsequently detected by a Silicon avalanche photodiode (Si-APD). In the experiment, dynamic strain disturbance up to 1.9 mε over 1.5 km of a polarization maintaining fiber is detected at a sampling rate of 30 Hz. An accuracy of ± 30 με and spatial resolution of 0.6 m are realized.

  9. The Double Edged Sword: A Brief Comparison of IT and Internet Development in Malaysia and Some Few Neighboring Countries in the Context of Digital Divide.

    ERIC Educational Resources Information Center

    Samad, Ramli Abdul

    This paper shows that, although a digital divide exists between developed and developing countries, the development of information technology (IT) and the Internet has had a profound political, social, and economic impact on developing countries. IT and the Internet revolution are shaping the world into new polarized entities due to the uneven…

  10. FACIN, a Double-Edged Sword of the Emerging Periodontal Pathogen Filifactor alocis: A Metabolic Enzyme Moonlighting as a Complement Inhibitor.

    PubMed

    Jusko, Monika; Miedziak, Beata; Ermert, David; Magda, Michal; King, Ben C; Bielecka, Ewa; Riesbeck, Kristian; Eick, Sigrun; Potempa, Jan; Blom, Anna M

    2016-10-15

    Periodontal disease is one of the most common inflammatory infectious diseases worldwide and it is associated with other syndromes, such as cardiovascular disease or rheumatoid arthritis. Recent advances in sequencing allowed for identification of novel periodontopathogens such as Gram-positive Filifactor alocis, but its virulence mechanisms remain largely unknown. We confirmed that F. alocis is a prevalent species in periodontitis patients, and we also observed strong correlation of this bacterium with clinical parameters, highlighting its role in the pathogenesis of the disease. Further, we found that preincubation of human serum with F. alocis resulted in abolished bactericidal activity and that F. alocis was surviving readily in full blood. We demonstrated that one of the key contributors to F. alocis complement resistance is a unique protein, FACIN (F. alocis complement inhibitor), which binds to C3, resulting in suppression of all complement pathways. Interestingly, FACIN is a nonclassical cell surface protein, a cytosolic enzyme acetylornithine transaminase, for which we now identified a moonlighting function. FACIN binds to C3 alone, but more importantly it also captures activated complement factor 3 within the complex with factor B, thereby locking in the convertase in an inactive state. Because of the indispensable role of alternative pathway convertase in amplifying complement cascades, its inhibition by FACIN results in a very potent downregulation of activated complement factor 3 opsonization on the pathogen surface, accompanied by reduction of downstream C5 cleavage.

  11. G-protein coupled receptors & autism -- reflections on a double-edged sword at the example of the oxytocin receptor system.

    PubMed

    Rojas Walh, Roy U

    2007-07-01

    G-protein coupled receptors (GPCR) tend to desensitize/internalize when exposed to excess agonist.Previously, we have supported the argument that in the case of the oxytocin receptor (OTR), excess agonist (oxytocin, OT) at birth could be implicated with behavioural disorders of the autistic spectrum. In this review, more recent evidence for this hypothesis is summarized, and it is juxtaposed against reports where exogenous OT was found beneficial in alleviating certain undesired behaviours. Facing this dichotomy, we suggest possible in silico drug discovery approaches to mitigate undesired side effect of OT administration/OTR desensitization, especially in the light of potentially emerging agonist therapies. For this, the most important structural features of OTR are reviewed, and we highlight here the need for higher level of theory studies at the easier approachable extracellular receptor side, where loop 3(e3) and the N-terminated strain of OTR appear to offer targets of particular interest for the development of an agent that conditions the action of excess OT. Another approach, based on the development of new agonists with an improved receptor activation to receptor phosphorylation ratio, is also discussed. Finally, the issue of OTR desensitization is put into the broader context of GPCR desensitization and possible implications for behavioural disorders, and the case is made for the usefulness of computational studies in this area.

  12. Millipede Defensive Compounds Are a Double-Edged Sword: Natural History of the Millipede-Parasitic Genus Myriophora Brown (Diptera: Phoridae).

    PubMed

    Hash, John M; Millar, Jocelyn G; Heraty, John M; Harwood, James F; Brown, Brian V

    2017-02-01

    Toxic defensive secretions produced by millipedes in the orders Julida, Spirobolida, Spirostreptida, and Polydesmida are highly repellent to most vertebrate and invertebrate natural enemies, but a few insects have evolved mechanisms to overcome these defenses. We demonstrate that highly specialized parasitic phorid flies in the species-rich genus Myriophora use volatile millipede defensive compounds as kairomones for host location. Of the two predominant quinone components in the defensive blend of juliform millipedes, 2-methoxy-3-methyl-1,4-benzoquinone alone was sufficient to attract adult flies of both sexes; however, a combination of 2-methoxy-3-methyl-1,4-benzoquinone and 2-methyl-1,4-benzoquinone increased attractiveness nearly threefold. We further discuss oviposition behavior, adult and larval feeding habits, life history parameters, and the potential competitive interactions between phorid flies in the genus Myriophora and other millipede-associated insects.

  13. Mutations for Worse or Better: Low-Fidelity DNA Synthesis by SOS DNA Polymerase V Is a Tightly Regulated Double-Edged Sword.

    PubMed

    Jaszczur, Malgorzata; Bertram, Jeffrey G; Robinson, Andrew; van Oijen, Antoine M; Woodgate, Roger; Cox, Michael M; Goodman, Myron F

    2016-04-26

    1953, the year of Watson and Crick, bore witness to a less acclaimed yet highly influential discovery. Jean Weigle demonstrated that upon infection of Escherichia coli, λ phage deactivated by UV radiation, and thus unable to form progeny, could be reactivated by irradiation of the bacterial host. Evelyn Witkin and Miroslav Radman later revealed the presence of the SOS regulon. The more than 40 regulon genes are repressed by LexA protein and induced by the coproteolytic cleavage of LexA, catalyzed by RecA protein bound to single-stranded DNA, the RecA* nucleoprotein filament. Several SOS-induced proteins are engaged in repairing both cellular and extracellular damaged DNA. There's no "free lunch", however, because error-free repair is accompanied by error-prone translesion DNA synthesis (TLS), involving E. coli DNA polymerase V (UmuD'2C) and RecA*. This review describes the biochemical mechanisms of pol V-mediated TLS. pol V is active only as a mutasomal complex, pol V Mut = UmuD'2C-RecA-ATP. RecA* donates a single RecA subunit to pol V. We highlight three recent insights. (1) pol V Mut has an intrinsic DNA-dependent ATPase activity that governs polymerase binding and dissociation from DNA. (2) Active and inactive states of pol V Mut are determined at least in part by the distinct interactions between RecA and UmuC. (3) pol V is activated by RecA*, not at a blocked replisome, but at the inner cell membrane.

  14. Are Academic Discounting and Devaluing Double-Edged Swords? Their Relations to Global Self-Esteem, Achievement Goals, and Performance among Stigmatized Students

    ERIC Educational Resources Information Center

    Loose, Florence; Regner, Isabelle; Morin, Alexandre J. S.; Dumas, Florence

    2012-01-01

    Often taken for granted, the coexistence of benefits and costs of discounting and devaluing has never been tested. Yet, not only are there inconsistent findings about the relations between these processes and global self-esteem, but little is known about their relations to motivation and performance. Here we simultaneously examined how academic…

  15. Re-investigation on reduced graphene oxide/Ag2CO3 composite photocatalyst: An insight into the double-edged sword role of RGO

    NASA Astrophysics Data System (ADS)

    Wang, Wenguang; Liu, Yuan; Zhang, Haiyan; Qian, Yannan; Guo, Zuchen

    2017-02-01

    Coupling graphene or reduced graphene oxide (RGO) with semiconductor photocatalysts has previously been proven to be an effective way for enhancing the photocatalytic activity and stability of the photocatalysts. Herein, the Ag2CO3/reduced graphene oxide composite was successfully prepared by a facile chemical precipitation method. The physical and chemical properties of the photocatalysts were characterized by X-ray diffraction, Raman spectra, scanning electron microscope, X-ray photoelectron spectroscopy, UV-vis diffuse-reflection spectra. The photocatalytic activity and cycling stability of the photocatalysts were evaluated by photocatalytic degradation of rhodamine B under visible light irradiation. The results showed that the RGO indeed improves the photocatalytic activity of Ag2CO3/RGO, which can be attributed to the reduced charge recombination and enhanced dye adsorption as well as the light harvesting by RGO. Nevertheless, it played a negative role to the photocatalytic cycling stability due to the strong aggregation of Ag2CO3 particles brought by the RGO sheets. This work may provide a re-examination of the role of RGO in enhancing the photocatalytic performances of the photocatalysts.

  16. "AVOID"ing harm by a double-edged sword: is there a role for ultrafiltration in heart failure?

    PubMed

    Kazory, Amir

    2016-03-01

    Prior studies comparing ultrafiltration with medical management for acute decompensated heart failure have yielded conflicting results. The AVOID-HF trial was designed as a definitive comparison of optimal ultrafiltration versus optimal diuretic-based medical therapy; unfortunately, the trial was terminated prematurely because of slow recruitment. The results of AVOID-HF nevertheless provide a rationale for well-designed, adequately powered trials to determine whether ultrafiltration has a role in the routine management of acute decompensated heart failure.

  17. Learner Dashboards a Double-Edged Sword? Students' Sense-Making of a Collaborative Critical Reading and Learning Analytics Environment for Fostering 21st-Century Literacies

    ERIC Educational Resources Information Center

    Pei-Ling Tan, Jennifer; Koh, Elizabeth; Jonathan, Christin; Yang, Simon

    2017-01-01

    The affordances of learning analytics (LA) tools and solutions are being increasingly harnessed for enhancing 21st century pedagogical and learning strategies and outcomes. However, use cases and empirical understandings of students' experiences with LA tools and environments aimed at fostering 21st century literacies, especially in the K-12…

  18. Bilingualism with and without CLIL, a Double-Edged Sword: Comparing Bilingual and Non Bilingual Young Learners' Beliefs about EFL and Science Learning

    ERIC Educational Resources Information Center

    Sandoval Brotons, Alfonso Victor

    2015-01-01

    Bilingualism and its reference methodology: CLIL are spreading at a very fast pace all through educative systems from some years on. The young status of bilingual programmes leads to little research about how bilingualism is influencing real learning contexts and which factors play important roles in that influence. In this way, this study aims to…

  19. Chronic exposure to stress predisposes to higher autoimmune susceptibility in C57BL/6 mice: glucocorticoids as a double-edged sword.

    PubMed

    Harpaz, Idan; Abutbul, Shai; Nemirovsky, Anna; Gal, Ram; Cohen, Hagit; Monsonego, Alon

    2013-03-01

    Stress activates the hypothalamic-pituitary-adrenocortical axis to promote the release of corticosterone (CORT), which consequently suppresses pathogenic stimulation of the immune system. Paradoxically, however, stress often promotes autoimmunity through yet unknown mechanisms. Here we investigated how chronic variable stress (CVS), and the associated alterations in CORT levels, affect the susceptibility to experimental autoimmune encephalomyelitis (EAE) in female and male C57BL/6 mice. Under baseline (nonstressed) conditions, females exhibited substantially higher CORT levels and an attenuated EAE with less mortality than males. However, CVS induced a significantly worsened EAE in females, which was prevented if CORT signaling was blocked. In addition, females under CVS conditions showed a shift toward proinflammatory Th1/Th17 versus Th2 responses and a decreased proportion of CD4(+) CD25(+) Treg cells. This demonstrates that whereas C57BL/6 female mice generally exhibit higher CORT levels and an attenuated form of EAE than males, they become less responsive to the immunosuppressive effects of CORT under chronic stress and thereby prone to a higher risk of destructive autoimmunity. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. The double-edged sword of the mammalian oocyte--advantages, drawbacks and approaches for basic and clinical analysis at the single cell level.

    PubMed

    Brayboy, L M; Wessel, G M

    2016-03-01

    Oocytes are usually the largest cells in the body and as such offer unique opportunities for single-cell analysis. Unfortunately, these cells are also some of the rarest in the mammalian female, usually necessitating single-cell analysis. In cases of infertility in humans, determining the quality of the oocyte is often restricted to a morphological analysis or to the study of cellular behaviors in the developing embryo. Minimally invasive approaches could greatly assist the clinician to prioritize oocytes for fertilization or following fertilization, which embryo to transfer back into the woman. Transcriptomics of human and mouse oocytes may have great utility, and recently it was learned that the polar body faithfully reflects the transcript prevalence in the oocyte. The polar body may thus serve as a minimally invasive proxy for an oocyte in the clinic. In the mouse, the transcriptomes of oocytes from mice of the same strain are markedly similar; no significant differences are apparent in transcript prevalence or identity. In human oocytes however, the transcript pool is highly variable. This is likely the result of different histories of each oocyte, in the age of the donor woman, the different hormonal exposures and the prolonged time from specification of the primary oocyte to the fully grown and ovulated egg. This variability in human oocytes also emphasizes the need for cell-by-cell analysis of the oocytes in vitro; which oocytes have a better potential for fertilization and development? To this end, new imaging capabilities are being employed. For example, a single-cell analytical device for oocytes (the simple perfusion apparatus, or SPA) enables investigators to load multiple oocytes in individual wells, to visualize them on the microscope and to use controlled temperature and media flow by perfusion for optimal clinical applications. Recently, developed Raman microspectroscopy approaches suggest that this imaging modality may enable more in-depth analysis of the molecular characteristics of an oocyte that, in combination with the SPA and transcriptomic approaches, might assist the clinician to prioritize more effectively human oocytes and embryos for transfer into women. This review is intended to update the reader on the status of the examination of single oocytes from a variety of approaches and to emphasize areas that may be primed for advancement in the near future. © The Author 2015. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Are Academic Discounting and Devaluing Double-Edged Swords? Their Relations to Global Self-Esteem, Achievement Goals, and Performance among Stigmatized Students

    ERIC Educational Resources Information Center

    Loose, Florence; Regner, Isabelle; Morin, Alexandre J. S.; Dumas, Florence

    2012-01-01

    Often taken for granted, the coexistence of benefits and costs of discounting and devaluing has never been tested. Yet, not only are there inconsistent findings about the relations between these processes and global self-esteem, but little is known about their relations to motivation and performance. Here we simultaneously examined how academic…

  2. The Ca2+-activated Cl− channel, ANO1 (TMEM16A), is a double-edged sword in cell proliferation and tumorigenesis

    PubMed Central

    Qu, Zhiqiang; Yao, Weicheng; Yao, Ruyong; Liu, Xiangping; Yu, Kuai; Hartzell, Criss

    2014-01-01

    Since anoctamin 1 ANO1 (TMEM16A) was found to be a molecular component of Ca2+-activated Cl− channels, its role in tumorigenesis has gained attention at a fast pace. ANO1 overexpression frequently occurs in the cancer tissues along with 11q13 chromosome amplification. Poor prognosis of many types of cancers has been closely correlated with ANO1 gene amplification and protein overexpression. ANO1 is now considered an excellent biomarker for certain cancers. Recent research suggests that it is the channel function of ANO1 that is involved in the tumorigenesis. However, how the overexpression of the functional ANO1 causes malignant transformation of tissues via signaling pathways, for example, MAPK remains to be investigated. Clarification of the reasons in future will avail to make ANO1 as a target for cancer treatment. PMID:24639373

  3. Extracellular and Intracellular Polyphenol Oxidases Cause Opposite Effects on Sensitivity of Streptomyces to Phenolics: A Case of Double-Edged Sword

    PubMed Central

    Yang, Han-Yu; Chen, Carton W.

    2009-01-01

    Many but not all species of Streptomyces species harbour a bicistronic melC operon, in which melC2 encodes an extracellular tyrosinase (a polyphenol oxidase) and melC1 encodes a helper protein. On the other hand, a melC-homologous operon (melD) is present in all sequenced Streptomyces chromosomes and could be isolated by PCR from six other species tested. Bioinformatic analysis showed that melC and melD have divergently evolved toward different functions. MelD2, unlike tyrosinase (MelC2), is not secreted, and has a narrower substrate spectrum. Deletion of melD caused an increased sensitivity to several phenolics that are substrates of MelD2. Intracellularly, MelD2 presumably oxidizes the phenolics, thus bypassing spontaneous copper-dependent oxidation that generates DNA-damaging reactive oxygen species. Surprisingly, melC+ strains were more sensitive rather than less sensitive to phenolics than melC− strains. This appeared to be due to conversion of the phenolics by MelC2 to more hydrophobic and membrane-permeable quinones. We propose that the conserved melD operon is involved in defense against phenolics produced by plants, and the sporadically present melC operon probably plays an aggressive role in converting the phenolics to the more permeable quinones, thus fending off less tolerant competing microbes (lacking melD) in the phenolic-rich rhizosphere. PMID:19826489

  4. The double-edged sword of the mammalian oocyte – advantages, drawbacks and approaches for basic and clinical analysis at the single cell level

    PubMed Central

    Brayboy, L.M.; Wessel, G.M.

    2016-01-01

    Oocytes are usually the largest cells in the body and as such offer unique opportunities for single-cell analysis. Unfortunately, these cells are also some of the rarest in the mammalian female, usually necessitating single-cell analysis. In cases of infertility in humans, determining the quality of the oocyte is often restricted to a morphological analysis or to the study of cellular behaviors in the developing embryo. Minimally invasive approaches could greatly assist the clinician to prioritize oocytes for fertilization or following fertilization, which embryo to transfer back into the woman. Transcriptomics of human and mouse oocytes may have great utility, and recently it was learned that the polar body faithfully reflects the transcript prevalence in the oocyte. The polar body may thus serve as a minimally invasive proxy for an oocyte in the clinic. In the mouse, the transcriptomes of oocytes from mice of the same strain are markedly similar; no significant differences are apparent in transcript prevalence or identity. In human oocytes however, the transcript pool is highly variable. This is likely the result of different histories of each oocyte, in the age of the donor woman, the different hormonal exposures and the prolonged time from specification of the primary oocyte to the fully grown and ovulated egg. This variability in human oocytes also emphasizes the need for cell-by-cell analysis of the oocytes in vitro; which oocytes have a better potential for fertilization and development? To this end, new imaging capabilities are being employed. For example, a single-cell analytical device for oocytes (the simple perfusion apparatus, or SPA) enables investigators to load multiple oocytes in individual wells, to visualize them on the microscope and to use controlled temperature and media flow by perfusion for optimal clinical applications. Recently, developed Raman microspectroscopy approaches suggest that this imaging modality may enable more in-depth analysis of the molecular characteristics of an oocyte that, in combination with the SPA and transcriptomic approaches, might assist the clinician to prioritize more effectively human oocytes and embryos for transfer into women. This review is intended to update the reader on the status of the examination of single oocytes from a variety of approaches and to emphasize areas that may be primed for advancement in the near future. PMID:26590170

  5. The reduced folate carrier (RFC) is cytotoxic to cells under conditions of severe folate deprivation. RFC as a double edged sword in folate homeostasis.

    PubMed

    Ifergan, Ilan; Jansen, Gerrit; Assaraf, Yehuda G

    2008-07-25

    The reduced folate carrier (RFC), a bidirectional anion transporter, is the major uptake route of reduced folates essential for a spectrum of biochemical reactions and thus cellular proliferation. However, here we show that ectopic overexpression of the RFC, but not of folate receptor alpha, a high affinity unidirectional folate uptake route serving here as a negative control, resulted in an approximately 15-fold decline in cellular viability in medium lacking folates but not in folate-containing medium. Moreover to explore possible mechanisms of adaptation to folate deficiency in various cell lines that express the endogenous RFC, we first determined the gene expression status of the following genes: (a) RFC, (b) ATP-driven folate exporters (i.e. MRP1, MRP5, and breast cancer resistance protein), and (c) folylpoly-gamma-glutamate synthetase and gamma-glutamate hydrolase (GGH), enzymes catalyzing folate polyglutamylation and hydrolysis, respectively. Upon 3-7 days of folate deprivation, semiquantitative reverse transcription-PCR analysis revealed a specific approximately 2.5-fold decrease in RFC mRNA levels in both breast cancer and T-cell leukemia cell lines that was accompanied by a consistent fall in methotrexate influx, serving here as an RFC transport activity assay. Likewise a 2.4-fold decrease in GGH mRNA levels and approximately 19% decreased GGH activity was documented for folate-deprived breast cancer cells. These results along with those of a novel mathematical biomodeling devised here suggest that upon severe short term (i.e. up to 7 days) folate deprivation RFC transport activity becomes detrimental as RFC, but not ATP-driven folate exporters, efficiently extrudes folate monoglutamates out of cells. Hence down-regulation of RFC and GGH may serve as a novel adaptive response to severe folate deficiency.

  6. Double-Edge Molecular Measurement of Lidar Wind Profiles at 355 nm

    NASA Technical Reports Server (NTRS)

    Flesia, Cristina; Korb, C. Laurence; Hirt, Christian; Einaudi, Franco (Technical Monitor)

    2000-01-01

    We built a direct detection Doppler lidar based on the double-edge molecular technique and made the first molecular based wind measurements using the eyesafe 355 nm wavelength. Three etalon bandpasses are obtained with Step etalons on a single pair of etalon plates. Long-term frequency drift of the laser and the capacitively stabilized etalon is removed by locking the etalon to the laser frequency. We use a low angle design to avoid polarization effects. Wind measurements of 1 to 2 m/s accuracy are obtained to 10 km altitude with 5 mJ of laser energy, a 750s integration, and a 25 cm telescope. Good agreement is obtained between the lidar and rawinsonde measurements.

  7. Elastic-plastic finite-element analyses of thermally cycled double-edge wedge specimens

    NASA Technical Reports Server (NTRS)

    Kaufman, A.; Hunt, L. E.

    1982-01-01

    Elastic-plastic stress-strain analyses were performed for double-edge wedge specimens subjected to thermal cycling in fluidized beds at 316 and 1088 C. Four cases involving different nickel-base alloys (IN 100, Mar M-200, NASA TAZ-8A, and Rene 80) were analyzed by using the MARC nonlinear, finite element computer program. Elastic solutions from MARC showed good agreement with previously reported solutions obtained by using the NASTRAN and ISO3DQ computer programs. Equivalent total strain ranges at the critical locations calculated by elastic analyses agreed within 3 percent with those calculated from elastic-plastic analyses. The elastic analyses always resulted in compressive mean stresses at the critical locations. However, elastic-plastic analyses showed tensile mean stresses for two of the four alloys and an increase in the compressive mean stress for the highest plastic strain case.

  8. Double-Edge Molecular Measurement of Lidar Wind Profiles in the VALID Campaign

    NASA Technical Reports Server (NTRS)

    Korb, C. Laurence; Flesia, Cristina; Lolli, Simone; Hirt, Christian

    2000-01-01

    We have developed a transportable container based direct detection Doppler lidar based on the double-edge molecular technique. The pulsed solid state system was built at the University of Geneva. It was used to make range resolved measurements of the atmospheric wind field as part of the VALID campaign at the Observatoire de Haute Provence in Provence, France in July 1999. Comparison of our lidar wind measurements, which were analyzed without knowledge of the results of rawinsonde measurements made under the supervision of ESA, show good agreement with these rawinsondes. These are the first Doppler lidar field measurements made with an eyesafe direct detection molecular-based system at 355 nm and serve as a demonstrator for future spaceborne direct detection wind systems such as the Atmospheric Dynamics mission. Winds are an important contributor to sea surface temperature measurements made with the Tropical Rainfall Measuring Mission (TRMM) and also affect the TRMM rainfall estimates.

  9. 0.6 GHz mapping of extended radio galaxies. I - Edge-brightened double sources

    NASA Astrophysics Data System (ADS)

    Jaegers, W. J.

    1987-02-01

    Radio observations made with the Westerbork telescope at 0.6 GHz are presented for 9 edge-brightened double sources: 3C 33.1, 3C 35, 3C 111, B 0844+316, 3C 223, 4C 26.35A, 4C 74.17.1, 3C 390.3 and 3C 452. Previously observed Westerbork data at 1.4 GHz are convolved for comparison with the 0.6 GHz observational data. Beside maps of the total intensity and linear polarization structure, the distributions of the spectral index, the depolarization and the rotation of the polarization position angle between 0.6 GHz and 1.4 GHz have been derived. Integrated values for the total intensity and the polarization are also given.

  10. Edge magnetoplasmons in double quantum wells: Influence of Coulomb coupling and tunneling

    NASA Astrophysics Data System (ADS)

    Vasilopoulos, P.; Balev, O. G.

    1998-12-01

    A random-phase approximation (RPA) treatment of fundamental edge magnetoplasmons (EMPs) in a double quantum well (DQW) is presented for strong magnetic fields, low temperatures, and total filling factor ν=2. It is valid for lateral confining potentials that allow Landau-level flattening to be neglected. The cyclotron and Zeeman energies are larger than the DQW energy splitting ( Δ2+4 T2) 1/2, where Δ is the splitting of the isolated wells and T the tunneling strength. For negligible T the inter-well Coulomb coupling drastically renormalizes the fundamental EMP of the corresponding single quantum well ( ν=1) and gives rise to two DQW fundamental EMPs. These modes can be affected further by varying the inter-well distance, along the z axis, and/or the separation of the wells' edges along the y axis. The charge profile of the fast and slow mode varies, respectively, in an acoustic and optical manner along the y axis. For strong T these modes can be modified essentially when Δ is changed by applying a transverse electric field to the DQW.

  11. Aharonov-Bohm and Aharonov-Casher tunneling effects and edge states in double-barrier structures

    SciTech Connect

    Bogachek, E.N.; Landman, U. )

    1994-07-15

    The simultaneous occurrence of Aharonov-Bohm (AB) and Aharonov-Casher (AC) effects due to edge states in double-barrier two-dimensional wires formed by an electrostatic confinement potential, in the quantum Hall effect regime, is discussed. The AC effect is manifested via a shift of the AB conductance oscillations, and a method for measurement of the effect is proposed.

  12. Rational behavior is a ‘double-edged sword’ when considering voluntary vaccination

    NASA Astrophysics Data System (ADS)

    Zhang, Haifeng; Fu, Feng; Zhang, Wenyao; Wang, Binghong

    2012-10-01

    behavior of individuals plays a ‘double-edged-sword’ role on the social effects.

  13. Cancer: fundamentals behind pH targeting and the double-edged approach.

    PubMed

    Koltai, Tomas

    2016-01-01

    targeting this vulnerable side of cancer development. It also analyzes the double-edged approach, which consists in pharmacologically increasing intracellular proton production and simultaneously decreasing proton extrusion creating intracellular acidity, acid stress, and eventual apoptosis.

  14. Cancer: fundamentals behind pH targeting and the double-edged approach

    PubMed Central

    Koltai, Tomas

    2016-01-01

    targeting this vulnerable side of cancer development. It also analyzes the double-edged approach, which consists in pharmacologically increasing intracellular proton production and simultaneously decreasing proton extrusion creating intracellular acidity, acid stress, and eventual apoptosis. PMID:27799782

  15. Homicide attempt with a Japanese samurai sword.

    PubMed

    Raul, Jean-Sébastien; Berthelon, Laurent; Geraut, Annie; Tracqui, Antoine; Ludes, Bertrand

    2003-07-01

    The use of Japanese swords for homicidal attempts is rare. A Japanese samurai sword is a sharp and cutting object. When faced with the use of this weapon, one must distinguish between stabs and incised wounds. Incised wounds can rarely lead to death, but because of the size of the weapon, stabs usually cause much more serious injuries. Stabs also imply a penetrating movement, whereas incised wounds can be the consequence of protective circular blows. Therefore, it is important to distinguish clinically between these two kinds of wounds. We report a case where the perpetrator argued he had given a circular blow, unfortunately hitting the victim. The pieces of evidence are discussed.

  16. Defect-induced band-edge reconstruction of a bismuth-halide double perovskite for visible-light absorption

    DOE PAGES

    Slavney, Adam H.; Leppert, Linn; Bartesaghi, Davide; ...

    2017-03-29

    In this study, halide double perovskites have recently been developed as less toxic analogs of the lead perovskite solar-cell absorbers APbX3 (A = monovalent cation; X = Br or I). However, all known halide double perovskites have large bandgaps that afford weak visible-light absorption. The first halide double perovskite evaluated as an absorber, Cs2AgBiBr6 (1), has a bandgap of 1.95 eV. Here, we show that dilute alloying decreases 1’s bandgap by ca. 0.5 eV. Importantly, time-resolved photoconductivity measurements reveal long-lived carriers with microsecond lifetimes in the alloyed material, which is very promising for photovoltaic applications. The alloyed perovskite described hereinmore » is the first double perovskite to show comparable bandgap energy and carrier lifetime to those of (CH3NH3)PbI3. By describing how energy- and symmetry-matched impurity orbitals, at low concentrations, dramatically alter 1’s band edges, we open a potential pathway for the large and diverse family of halide double perovskites to compete with APbX3 absorbers.« less

  17. Interlayer current near the edge of an InAs/GaSb double quantum well in proximity with a superconductor

    NASA Astrophysics Data System (ADS)

    Kononov, A.; Egorov, S. V.; Titova, N.; Semyagin, B. R.; Preobrazhenskii, V. V.; Putyato, M. A.; Emelyanov, E. A.; Deviatov, E. V.

    2017-04-01

    We investigate charge transport through the junction between a niobium superconductor and the edge of a two-dimensional electron-hole bilayer, realized in an InAs/GaSb double quantum well. For the transparent interface with a superconductor, we demonstrate that the junction resistance is determined by the interlayer charge transfer near the interface. From an analysis of experimental I-V curves, we conclude that the proximity-induced superconductivity efficiently couples electron and hole layers at low currents. The critical current demonstrates periodic dependence on the in-plane magnetic field, while it is monotonic for the field that is normal to the bilayer plane.

  18. Inter-layer edge tunneling and transport properties in separately contacted double-layer quantum-Hall systems

    NASA Astrophysics Data System (ADS)

    Yoshioka, Daijiro

    1998-01-01

    A theory of transport in the quantum-Hall regime is developed for separately contacted double-layer electron systems. Inter-layer tunneling provides a channel for equilibration of the distribution functions in the two layers at the edge states. Resistances and transresistances for various configurations of the electrodes are calculated as functions of the inter-layer tunneling amplitude. Induced current in one of the layer by a current in the other is also calculated. It is shown that reflection at the leads causes change in the results for some electrode configurations. The results obtained in this work is consistent with recent experiments.

  19. Na double-edge magneto-optic filter for Na lidar profiling of wind and temperature in the lower atmosphere.

    PubMed

    Huang, Wentao; Chu, Xinzhao; Williams, B P; Harrell, S D; Wiig, Johannes; She, C-Y

    2009-01-15

    A Na double-edge magneto-optic filter is proposed for incorporation into the receiver of a three-frequency Na Doppler lidar to extend its wind and temperature measurements into the lower atmosphere. Two prototypes based on cold- and hot-cell designs were constructed and tested with laser scanning and quantum mechanics modeling. The hot-cell filter exhibits superior performances over the cold-cell filter containing buffer gas. Lidar simulations, metrics, and error analyses show that simultaneous wind and temperature measurements are feasible in the altitude range of 20-50 km using the hot-cell filter and reasonable Na lidar parameters.

  20. Oxygen Use in Neonatal Care: A Two-edged Sword

    PubMed Central

    Perrone, Serafina; Bracciali, Carlotta; Di Virgilio, Nicola; Buonocore, Giuseppe

    2017-01-01

    In the neonatal period, the clinical use of oxygen should be taken into consideration for its beneficial and toxicity effects. Oxygen toxicity is due to the development of reactive oxygen species (ROS) such as OH• that is one of the strongest oxidants in nature. Of note, generation of ROS is a normal occurrence in human and it is involved in a myriad of physiological reactions. Anyway an imbalance between production of oxidant species and antioxidant defenses, called oxidative stress, could affect various aspect of organisms’ physiology and it could determine pathological consequences to living beings. Neonatal oxidative stress is essentially due to decreased antioxidants, increased ROS, or both. Studies have demonstrated that antioxidant capacity is lower in preterm newborns than term babies. This well-known deficiency of antioxidant factors is only a piece of a cohort of factors, which can be involved in the neonatal oxidative stress and the increased production of ROS may be a main factor. Mechanisms of ROS generation are: mitochondrial respiratory chain, free iron and Fenton reaction, inflammation, hypoxia and/or ischemia, reperfusion, and hyperoxia. Oxidative stress following hyperoxia has been recognized to be responsible for lung, central nervous system, retina, red blood cell injuries, and possibly generalized tissue damage. When supplemental oxygen is needed for care, it would be prudent to avoid changes and fluctuations in SpO2. The definition of the safest level of oxygen saturations in the neonate remains an area of active research. Currently, on the basis of the published evidences, the most suitable approach would be to set alarm limits between 90 and 95%. It should allow to avoid SpO2 values associated with potential hypoxia and/or hyperoxia. Although the usefulness of antioxidant protection in the neonatal period is still under investigation, the risk of tissue damage due to oxidative stress in perinatal period should not be underestimated. PMID:28119904

  1. Free Internet and Social Media: A Dual-Edged Sword

    DTIC Science & Technology

    2014-02-13

    of all written information thereby controlling the beliefs of an illiterate society. This information dominance occurred since only monks reproduced...of Protestantism. 5 The Catholic Church’s seven hundred years of top-down information dominance gradually lost sway despite defensive measures. To...on the tit for tat relationship between online oppositionists and regimes. While China seeks to maintain information dominance , it must relinquish

  2. Nutritional therapy and infectious diseases: a two-edged sword

    PubMed Central

    Donabedian, Haig

    2006-01-01

    The benefits and risks of nutritional therapies in the prevention and management of infectious diseases in the developed world are reviewed. There is strong evidence that early enteral feeding of patients prevents infections in a variety of traumatic and surgical illnesses. There is, however, little support for similar early feeding in medical illnesses. Parenteral nutrition increases the risk of infection when compared to enteral feeding or delayed nutrition. The use of gastric feedings appears to be as safe and effective as small bowel feedings. Dietary supplementation with glutamine appears to lower the risk of post-surgical infections and the ingestion of cranberry products has value in preventing urinary tract infections in women. PMID:16952310

  3. Asymptotic theory of double layer and shielding of electric field at the edge of illuminated plasma

    SciTech Connect

    Benilov, M. S.; Thomas, D. M.

    2014-04-15

    The method of matched asymptotic expansions is applied to the problem of a collisionless plasma generated by UV illumination localized in a central part of the plasma in the limiting case of small Debye length λ{sub D}. A second-approximation asymptotic solution is found for the double layer positioned at the boundary of the illuminated region and for the un-illuminated plasma for the plane geometry. Numerical calculations for different values of λ{sub D} are reported and found to confirm the asymptotic results. The net integral space charge of the double layer is asymptotically small, although in the plane geometry it is just sufficient to shield the ambipolar electric field existing in the illuminated region and thus to prevent it from penetrating into the un-illuminated region. The double layer has the same mathematical nature as the intermediate transition layer separating an active plasma and a collisionless sheath, and the underlying physics is also the same. In essence, the two layers represent the same physical object: a transonic layer.

  4. The Pill vs. the Sword: Additional Considerations

    PubMed Central

    Lottes, Ilsa L.

    2015-01-01

    In this paper, I present additional information for policy-makers and researchers to consider in response to the view proposed by Potts et al that "the pill is mightier than the sword." I identify states with both high rates of terrorism and a youth bulge and discuss correlates of both these societal characteristics. The research examined supports the view that factors other than access to family planning are more important in facilitating terrorism. PMID:26673473

  5. Single and double ionization of the camphor molecule excited around the C 1s edge.

    PubMed

    de Castilho, R B; Ramalho, T C; Nunez, C V; Coutinho, L H; Santos, A C F; Pilling, S; Lago, A F; Silva-Moraes, M O; de Souza, G G B

    2014-08-15

    An interesting class of volatile compounds, the monoterpenes, is present in some plants although their functions are not yet fully understood. We have studied the interaction of the camphor molecule with monochromatic high-energy photons (synchrotron radiation) using time-of-flight mass spectrometry and coincidence techniques. A commercial sample of S-camphor was admitted into the vacuum chamber, without purification, through an inlet system. Monochromatic light with energy around the C 1s edge was generated by the TGM beamline at the Brazilian Synchrotron Facility. A Wiley-McLaren mass spectrometer was used to characterize and detect the ions formed by the camphor photoionization. The data analysis was supported by energy calculations. Although the fragmentation patterns were basically the same at 270 eV and 330 eV, it was observed that above the C 1s edge the contribution to the spectrum from lower mass/charge fragment ions increased, pointing to a higher degree of dissociation of the molecule. Projections of the PEPIPICO spectra demonstrated the existence of unstable doubly charged species. The Gibbs free energy was calculated using the Møller-Plesset perturbation theory (MP2) for the neutral, singly and doubly excited camphor molecule. Our PEPIPICO spectrum clearly demonstrated the formation of doubly ionic dissociative species. From a slope analysis, we propose a secondary decay after a deferred charge separation mechanism in which, after a few steps, the camphor dication dissociates into C2 H3 (+) and C3 H5 (+) . This is the main relaxation route observed at 270 eV and 330 eV. The large energy difference between the mono and the dication (of the order of 258.2 kcal/mol) may explain the experimentally observed absence of stable dications in the spectra, because their formation is disadvantaged energetically. Copyright © 2014 John Wiley & Sons, Ltd.

  6. Hydrophobic versus double-square-edged hydrophilic foldable acrylic intraocular lens: effect on posterior capsule opacification.

    PubMed

    Iwase, Takeshi; Nishi, Yutarou; Oveson, Brian C; Jo, Young-Joon

    2011-06-01

    To evaluate posterior capsule opacification (PCO) 2 years after cataract surgery with implantation of a hydrophobic acrylic or single-piece sharp-edged hydrophilic acrylic intraocular lens (IOL). Toyama Prefectural Central Hospital, Toyama, Japan. Case-control study. Patients with bilateral senile cataract were prospectively randomized to receive a hydrophobic IOL (Acrysof SA60AT) in 1 eye and a hydrophilic IOL (Meridian HP60M) in the other eye. The PCO density value, degree of IOL decentration and tilt, and anterior chamber depth (ACD) were measured using Scheimpflug videophotography 1, 6, 12, 18, and 24 months after surgery. Visual acuity and the number of eyes requiring neodymium:YAG laser capsulotomy were also assessed. The study evaluated 16 eyes (63 patients). The PCO value in the hydrophilic group increased significantly with time and was statistically significantly greater than in the hydrophobic group 18 and 24 months postoperatively (both P < .001). The capsulotomy rate was statistically significantly higher in the hydrophilic group than in the hydrophobic group (P < .01). Visual acuity in the hydrophilic group worsened significantly with time and was statistically significantly worse than in the hydrophobic group at 18 and 24 months (both P < .001). Intraocular lens decentration, IOL tilt, and the ACD did not change significantly during the follow-up in either group (P > .05), and there were no statistically significant postoperative differences in these parameters between the 2 IOL groups (P > .05). Two years after surgery, the hydrophobic IOL group had less PCO, a lower capsulotomy rate, and better visual acuity than the hydrophilic IOL group. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  7. Estimation of Neutral Density in Edge Plasma with Double Null Configuration in EAST

    NASA Astrophysics Data System (ADS)

    Zhang, Ling; Xu, Guosheng; Ding, Siye; Gao, Wei; Wu, Zhenwei; Chen, Yingjie; Huang, Juan; Liu, Xiaoju; Zang, Qing; Chang, Jiafeng; Zhang, Wei; Li, Yingying; Qian, Jinping

    2011-08-01

    In this work, population coefficients of hydrogen's n = 3 excited state from the hydrogen collisional-radiative (CR) model, from the data file of DEGAS 2, are used to calculate the photon emissivity coefficients (PECs) of hydrogen Balmer-α (n = 3 → n = 2) (Hα). The results are compared with the PECs from Atomic Data and Analysis Structure (ADAS) database, and a good agreement is found. A magnetic surface-averaged neutral density profile of typical double-null (DN) plasma in EAST is obtained by using FRANTIC, the 1.5-D fluid transport code. It is found that the sum of integral Dα and Hα emission intensity calculated via the neutral density agrees with the measured results obtained by using the absolutely calibrated multi-channel poloidal photodiode array systems viewing the lower divertor at the last closed flux surface (LCFS). It is revealed that the typical magnetic surface-averaged neutral density at LCFS is about 3.5 × 1016 m-3.

  8. Double-difference traveltime tomography with edge-preserving regularization and a priori interfaces

    NASA Astrophysics Data System (ADS)

    Lin, Youzuo; Syracuse, Ellen M.; Maceira, Monica; Zhang, Haijiang; Larmat, Carene

    2015-05-01

    Conventional traveltime seismic tomography methods with Tikhonov regularization (L2 norm) typically produce smooth models, but these models may be inappropriate when subsurface structure contains discontinuous features, such as faults or fractures, indicating that tomographic models should contain sharp boundaries. For this reason, we develop a double-difference (DD) traveltime tomography method that uses a modified total-variation regularization scheme incorporated with a priori information on interfaces to preserve sharp property contrasts and obtain accurate inversion results. In order to solve the inversion problem, we employ an alternating minimization method to decouple the original DD tomography problem into two separate subproblems: a conventional DD tomography with Tikhonov regularization and a L2 total-variation inversion. We use the LSQR linear solver to solve the Tikhonov inversion and the split-Bregman iterative method to solve the total-variation inversion. Through our numerical examples, we show that our new DD tomography method yields more accurate results than the conventional DD tomography method at almost the same computational cost.

  9. System Administration Support/SWORDS G2

    NASA Technical Reports Server (NTRS)

    Dito, Scott Joseph

    2014-01-01

    The Soldier-Warfighter Operationally Responsive Deployer for Space (SWORDS) rocket is a dedicated small satellite launcher that will minimize danger and complexity in order to allow soldiers in the field to put payloads of up to 25kg into orbit from the field. The SWORDSG2 project is the development of a model, simulation, and ultimately a working application that will control and monitor the cryogenic fluid delivery to the SWORDS rocket for testing purposes. To accomplish this, the project is using the programming language environment Gensym G2. The environment is an all-inclusive application that allows development, testing, modeling, and finally operation of the unique application through graphical and programmatic methods. In addition, observation of the current cryogenic fluid delivery system in the Kennedy Space Center Cry Lab has allowed me to gain valuable experience of fluid systems and propelant delivery that is valuable to our team when developing amd modeling our own system.The ultimate goal of having a test-ready application to show to the heads of the project, and demonstrating G2's capabilities, by late 2014 will require hard work and intense study and understanding of not only the programming aspect but also the physical phenomena we want to model, observe, and control.

  10. The Pill vs. the Sword: Additional Considerations Comment on "The Pill Is Mightier Than the Sword".

    PubMed

    Lottes, Ilsa L

    2015-08-21

    In this paper, I present additional information for policy-makers and researchers to consider in response to the view proposed by Potts et al that "the pill is mightier than the sword." I identify states with both high rates of terrorism and a youth bulge and discuss correlates of both these societal characteristics. The research examined supports the view that factors other than access to family planning are more important in facilitating terrorism. © 2015 by Kerman University of Medical Sciences.

  11. Edge Stability and Performance of the ELM-Free Quiescent H-Mode and the Quiescent Double Barrier Mode on DIII-D

    SciTech Connect

    West, W P; Burrell, K H; Casper, T A; . Doyle, E J; Snyder, P B; Gohil, P; Lao, L L; Lasnier, C J; Leonard, A W; Nave, M F; Osborne, T H; Thomas, D M; Wang, G; Zeng, L

    2004-12-03

    The quiescent H (QH) mode, an edge localized mode (ELM)-free, high-confinement mode, combines well with an internal transport barrier to form quiescent double barrier (QDB) stationary state, high performance plasmas. The QH-mode edge pedestal pressure is similar to that seen in ELMing phases of the same discharge, with similar global energy confinement. The pedestal density in early ELMing phases of strongly pumped counter injection discharges drops and a transition to QH-mode occurs, leading to lower calculated edge bootstrap current. Plasmas current ramp experiment and ELITE code modeling of edge stability suggest that QH-modes lie near an edge current stability boundary. At high triangularity, QH-mode discharges operate at higher pedestal density and pressure, and have achieved ITER level values of {beta}{sub PED} and {nu}*. The QDB achieves performance of {alpha}{sub N}H{sub 89} {approx} 7 in quasi-stationary conditions for a duration of 10 tE, limited by hardware. Recently we demonstrated stationary state QDB discharges with little change in kinetic and q profiles (q{sub 0} > 1) for 2 s, comparable to ELMing ''hybrid scenarios'', yet without the debilitating effects of ELMs. Plasma profile control tools, including electron cyclotron heating and current drive and neutral beam heating, have been demonstrated to control simultaneously the q profile development, the density peaking, impurity accumulation and plasma beta.

  12. Edward's sword? - A non-destructive study of a medieval king's sword

    SciTech Connect

    Segebade, Chr.

    2013-04-19

    Non-destructive and instrumental methods including photon activation analysis were applied in an examination of an ancient sword. It was tried to find indication of forgery or, if authentic, any later processing and alteration. Metal components of the hilt and the blade were analysed by instrumental photon activation. Non-destructive metallurgical studies (hardness measurements, microscopic microstructure analysis) are briefly described, too. The results of these investigations did not yield indication of non-authenticity. This stood in agreement with the results of stylistic and scientific studies by weapon experts.

  13. Crack growth behavior under creep-fatigue conditions using compact and double edge notch tension-compression specimens

    NASA Astrophysics Data System (ADS)

    Narasimha Chary, Santosh Balaji

    The American Society for Testing and Materials (ASTM) has recently developed a new standard for creep-fatigue crack growth testing, E 2760-10, that supports testing compact specimens, C(T), under load controlled conditions. C(T) specimens are commonly used for fatigue and creep-fatigue crack growth testing under constant-load-amplitude conditions. The use of these specimens is limited to positive load ratios. They are also limited in the amount of crack growth data that can be developed at high stress intensity values due to accumulation of plastic and/or creep strains leading to ratcheting in the specimen. Testing under displacement control can potentially address these shortcomings of the load-controlled tests for which the C(T) geometry is unsuitable. A double edge notch tension-compression, DEN(T-C), specimen to perform displacement controlled creep-fatigue crack growth testing is developed and optimized with the help of finite element and boundary element analyses. Accurate expressions for estimating the fracture mechanics crack tip parameters such as the stress intensity parameter, K, the crack mouth opening displacement (CMOD), and the load-line displacement (LLD) are developed over a wide range of crack sizes for the DEN(T-C) specimen. A new compliance relationship for use in experimental testing has been developed by using the compliance form available in ASTM E-647 standard. Experimentally determined compliance value compared well with the new relation for C15 steel (AISI 1015) and P91 steel tested at room and elevated temperature conditions respectively. Fatigue crack growth rate data generated using the DEN(T-C) specimens on the two metallic materials are in good agreement with the data generated using standard compact specimens; thus validating the stress-intensity factor and the compliance equation for the double edge notch tension-compression specimen. The testing has shown that the DEN(T-C) specimen is prone to crack asymmetry issues. Through

  14. Blue light generated by intra-cavity frequency doubling of an edge-emitting diode laser with a periodically poled LiNbO3 crystal.

    PubMed

    Li, Kang; Yao, Aiyun; Copner, N J; Gawith, C B E; Knight, Ian G; Pfeiffer, Hans-Ulrich; Musk, Bob

    2009-11-23

    We demonstrate for the first time to our knowledge intra-cavity frequency doubling (ICFD) of an edge-emitter diode laser using a 10 mm-long 5.0 microm periodically poled LiNbO(3) (PPLN) crystal. An optical output power of 33 mW second harmonic blue light at 490.5 nm is generated at 1.0 A injection current, equivalent to an overall wall-plug efficiency of 1.8%. The measured M(2) values of blue beam are 1.7 and 2.4 along the fast and slow axis.

  15. Exponential Increase in Relative Biological Effectiveness Along Distal Edge of a Proton Bragg Peak as Measured by Deoxyribonucleic Acid Double-Strand Breaks

    PubMed Central

    Cuaron, John J.; Chang, Chang; Lovelock, Michael; Higginson, Daniel S.; Mah, Dennis; Cahlon, Oren; Powell, Simon

    2016-01-01

    Purpose To quantify the relative biological effectiveness (RBE) of the distal edge of the proton Bragg peak, using an in vitro assay of DNA double-strand breaks (DSBs). Methods and Materials U2OS cells were irradiated within the plateau of a spread-out Bragg peak and at each millimeter position along the distal edge using a custom slide holder, allowing for simultaneous measurement of physical dose. A reference radiation signal was generated using photons. The DNA DSBs at 3 hours (to assess for early damage) and at 24 hours (to assess for residual damage and repair) after irradiation were measured using the γH2AX assay and quantified via flow cytometry. Results were confirmed with clonogenic survival assays. A detailed map of the RBE as a function of depth along the Bragg peak was generated using γH2AX measurements as a biological endpoint. Results At 3 hours after irradiation, DNA DSBs were higher with protons at every point along the distal edge compared with samples irradiated with photons to similar doses. This effect was even more pronounced after 24 hours, indicating that the impact of DNA repair is less after proton irradiation relative to photons. The RBE demonstrated an exponential increase as a function of depth and was measured to be as high as 4.0 after 3 hours and as high as 6.0 after 24 hours. When the RBE-corrected dose was plotted as a function of depth, the peak effective dose was extended 2-3 mm beyond what would be expected with physical measurement. Conclusions We generated a highly comprehensive map of the RBE of the distal edge of the Bragg peak, using a direct assay of DNA DSBs in vitro. Our data show that the RBE of the distal edge increases with depth and is significantly higher than previously reported estimates. PMID:27084629

  16. Covenants with Weak Swords: ISO 14001 and Facilities' Environmental Performance

    ERIC Educational Resources Information Center

    Potoski, Matthew; Prakash, Aseem

    2005-01-01

    Voluntary environmental programs are codes of progressive environmental conduct that firms pledge to adopt. This paper investigates whether ISO 14001, a voluntary program with a weak sword--a weak monitoring and sanctioning mechanism--can mitigate shirking and improve participants' environmental performance. Sponsored by the International…

  17. Covenants with Weak Swords: ISO 14001 and Facilities' Environmental Performance

    ERIC Educational Resources Information Center

    Potoski, Matthew; Prakash, Aseem

    2005-01-01

    Voluntary environmental programs are codes of progressive environmental conduct that firms pledge to adopt. This paper investigates whether ISO 14001, a voluntary program with a weak sword--a weak monitoring and sanctioning mechanism--can mitigate shirking and improve participants' environmental performance. Sponsored by the International…

  18. The turn of the sword: length increases male swimming costs in swordtails.

    PubMed

    Basolo, Alexandra L; Alcaraz, Guillermina

    2003-08-07

    Sexual selection via female mate choice can result in the evolution of elaborate male traits that incur substantial costs for males. Despite increased interest in how female mating preferences contribute to the evolution of male traits, few studies have directly quantified the locomotor costs of such traits. A sexually selected trait that could affect movement costs is the sword exhibited by male swordtail fishes: while longer swords may increase male mating success, they could negatively affect the hydrodynamic aspects of swimming activities. Here, we examine the energetic costs of the sword in Xiphophorus montezumae by experimentally manipulating sword length and measuring male aerobic metabolism during two types of activity, routine swimming and courtship swimming. Direct measurements of oxygen consumption indicate that males with longer swords expend more energy than males with shortened swords during both types of swimming. In addition, the sword increases the cost of male courtship. Thus, while sexual selection via female choice favours long swords, males with longer swords experience higher metabolic costs during swimming, suggesting that sexual and natural selection have opposing effects on sword evolution. This study demonstrates a hydrodynamic cost of a sexually selected trait. In addition, this study discriminates between the cost of a sexually selected trait used in courtship and other courtship costs.

  19. Characterization of an Indian sword: classic and noninvasive methods of investigation in comparison

    NASA Astrophysics Data System (ADS)

    Barzagli, E.; Grazzi, F.; Williams, A.; Edge, D.; Scherillo, A.; Kelleher, J.; Zoppi, M.

    2015-04-01

    The evolution of metallurgy in history is one of the most interesting topics in Archaeometry. The production of steel and its forging methods to make tools and weapons are topics of great interest in the field of the history of metallurgy. In the production of weapons, we find almost always the highest level of technology. These were generally produced by skilled craftsmen who used the best quality materials available. Indian swords are an outstanding example in this field and one of the most interesting classes of objects for the study of the evolution of metallurgy. This work presents the study of a Shamsheer (a sword with a curved blade with single edge) made available by the Wallace Collection in London. The purpose of this study was to determine the composition, the microstructure, the level and the direction of residual strain and their distribution in the blade. We have used two different approaches: the classical one (metallography) and a nondestructive technique (neutron diffraction): In this way, we can test differences and complementarities of these two techniques. To obtain a good characterization of artifacts studied by traditional analytical methods, an invasive approach is required. However, the most ancient objects are scarce in number, and the most interesting ones are usually in an excellent state of conservation, so it is unthinkable to apply techniques with a destructive approach. The analysis of blades that has been performed by metallographic microscopy has demonstrated the specificity of the production of this type of steel. However, metallographic analysis can give only limited information about the structural characteristics of these artifacts of high quality, and it is limited to the sampled areas. The best approach for nondestructive analysis is therefore to use neutron techniques.

  20. Casting Simulation of an Austrian Bronze Age Sword Hilt

    NASA Astrophysics Data System (ADS)

    Pola, Annalisa; Mödlinger, Marianne; Piccardo, Paolo; Montesano, Lorenzo

    2015-07-01

    Bronze Age swords with a metal hilt can be considered the peak of Bronze Age casting technologies. To reconstruct the casting techniques used more than 3000 years ago, a metal hilted sword of the Schalenknauf type from Lower Austria was studied with the aid of macroscopic analyses and simulation of mold filling and casting solidification. A three-dimensional model of the hilt was created based on optical scanner measurements performed on a hilt recently discovered during archaeological excavations. Three different configurations of the gating system were considered, two on the pommel disk and one on the knob, and the effect of its location on the formation of casting defects was investigated. Three-dimensional computed tomography was used to detect internal defects, such as gas and shrinkage porosity, which were then compared with those calculated by simulation. The best match between actual and predicted hilt quality demonstrated the location of the gating system, which turned out to be on the pommel disk.

  1. Fabrication of a Bronze Age Sword using Ancient Techniques

    NASA Astrophysics Data System (ADS)

    Sapiro, David; Webler, Bryan

    2016-12-01

    A khopesh was cast and forged for the TMS 2016 Bladesmithing Symposium. The khopesh was the first sword style, originating during the Bronze Age in the Near East. The manufacturing process used in this study closely followed Bronze Age techniques to determine the plausibility of open mold casting coupled with cold work and annealing cycles. Forging and annealing cycles substantially increased blade strength and diminished intergranular δ-phase inclusions. While a functional blade was not completed due to casting defects, the process gives valuable insight into the effort required to fabricate a khopesh during the Bronze Age. Forging and annealing cycles following casting were necessary to produce the mechanical properties desired in a sword.

  2. Simulating Terrestrial Gamma-ray Flashes using SWORD (Invited)

    NASA Astrophysics Data System (ADS)

    Gwon, C.; Grove, J.; Dwyer, J. R.; Mattson, K.; Polaski, D.; Jackson, L.

    2013-12-01

    We report on simulations of the relativistic feedback discharges involved with the production of terrestrial gamma-ray flashes (TGFs). The simulations were conducted using Geant4 using the SoftWare for the Optimization of Radiation Detectors (SWORD) framework. SWORD provides a graphical interface for setting up simulations in select high-energy radiation transport engines. Using Geant4, we determine avalanche length, the energy spectrum of the electrons and gamma-rays as they leave the field region, and the feedback factor describing the degree to which the production of energetic particles is self-sustaining. We validate our simulations against previous work in order to determine the reliability of our results. This work is funded by the Office of Naval Research.

  3. On the Edge Refraction Contrast Imaging on a Conventional Neutron Diffractometer Employing Dispersive Double-Crystal Monochromator

    NASA Astrophysics Data System (ADS)

    Mikula, P.; Vrána, M.; Em, V.; Čapek, J.; Korytár, D.

    2016-09-01

    Conventional radiography is based on absorption effects, which depend only on the imaginary part of the refractive index. However, slits and macroscopic objects such as edges give rise to refraction and this phenomenon can be effectively used in the so called phase- contrast imaging. In addition to the absorption contrast in the conventional radiography, it exploits also contributions of phase shifts induced by the propagation of a coherent neutron (or X-ray) beam through an investigated sample. The difference in real part of the refrative index between a studied detail and its vicinity results in a phase shift between the wave transmitted through and outside the detail. Due to this phase shift, the two waves interfere. However, the used radiation has to possess a sufficiently high spatial coherence permitting one to detect resulting interference pattern. In this contribution we present two simple neutron diffractometer configurations based on two bent perfect Si crystals which provide a high spatial coherence beam of sufficient intensity which could be potentially used in some phase contrast radiography experiments.

  4. Spectral analysis of the line-width and line-edge roughness transfer during self-aligned double patterning approach

    NASA Astrophysics Data System (ADS)

    Dupuy, E.; Pargon, E.; Fouchier, M.; Grampeix, H.; Pradelles, J.; Darnon, M.; Pimenta-Barros, P.; Barnola, S.; Joubert, O.

    2015-03-01

    We report a 20 nm half-pitch self-aligned double patterning (SADPP) process based on a resist-core approach. Line/space 20/20 nm features in silicon are successfully obtained with CDvariation, LWR and LER of 0.7 nm, 2.4 nm and 2.3 nm respectively. The LWR and LER are characterized at each technological step of the process using a power spectral density fitting method, which allows a spectral analysis of the roughness and the determination of unbiased roughness values. Although the SADP concept generates two asymmetric populations of lines, the final LLWR and LER are similar. We show that this SADP process allows to decrease significantly the LWR and the LER of about 62% and 48% compared to the initial photoresist patterns. This study also demonstrates that SADP is a very powerful concept to decrease CD uniformity and LWR especially in its low-frequency components to reach sub-20 nm node requirements. However, LER low-frequency components are still high and remain a key issue tot address for an optimized integration.

  5. Band edge tailoring of InGaAs/AlAsSb coupled double quantum wells for a monolithically integrated all-optical switch.

    PubMed

    Feng, Jijun; Akimoto, Ryoichi; Gozu, Shin-ichiro; Mozume, Teruo; Hasama, Toshifumi; Ishikawa, Hiroshi

    2013-07-01

    We demonstrate a compact all-optical Michelson interferometer (MI) gating switch with monolithic integration of two different bandgap energies. Based on the ion-induced intermixing in InGaAs/AlAsSb coupled double quantum wells, the blueshift of the band edge can be tailored. Through phosphorus ion implantation with a dose of 5 × 10(14) cm(-2) and subsequent annealing at 720 °C for 60 s, an implanted sample can acquire a high transmittance compared with the as-grown one. Meanwhile, the cross-phase modulation (XPM) efficiency of a non-implanted sample undergoing the same annealing process decreases little. An implanted part for signal propagation and a non-implanted section for XPM are thus monolithically integrated for an MI switch by an area-selective manner. Full switching of a π-rad nonlinear phase shift is achieved with pump pulse energy of 5.6 pJ at a 10-GHz repetition rate.

  6. Non-specificity of ethylene inhibitors: 'double-edged' tools to find out new targets involved in the root morphogenetic programme.

    PubMed

    Le Deunff, E; Lecourt, J

    2016-05-01

    In the last decade, genetic and pharmacological approaches have been used to explore ethylene biosynthesis and perception in order to study the role of ethylene and ethylene/auxin interaction in root architecture development. However, recent findings with pharmacological approaches highlight the non-specificity of commonly used inhibitors. This suggests that caution is required for interpreting these studies and that the use of pharmacological agents is a 'double-edged' tool. On one hand, non-specific effects make interpretation difficult unless other experiments, such as with different mutants or with multiple diversely acting chemicals, are conducted. On the other hand, the non-specificity of inhibitors opens up the possibility of uncovering some ligands or modulators of new receptors such as plant glutamate-like receptors and importance of some metabolic hubs in carbon and nitrogen metabolism such as the pyridoxal phosphate biosynthesis involved in the regulation of the root morphogenetic programme. Identification of such targets is a critical issue to improve the efficiency of absorption of macronutrients in relation to root the morphogenetic programme.

  7. Field demonstration of simultaneous wind and temperature measurements from 5 to 50 km with a Na double-edge magneto-optic filter in a multi-frequency Doppler lidar.

    PubMed

    Huang, Wentao; Chu, Xinzhao; Wiig, Johannes; Tan, Bo; Yamashita, Chihoko; Yuan, T; Yue, J; Harrell, S D; She, C-Y; Williams, B P; Friedman, J S; Hardesty, R M

    2009-05-15

    We report the first (to our knowledge) field demonstration of simultaneous wind and temperature measurements with a Na double-edge magneto-optic filter implemented in the receiver of a three-frequency Na Doppler lidar. Reliable winds and temperatures were obtained in the altitude range of 10-45 km with 1 km resolution and 60 min integration under the conditions of 0.4 W lidar power and 75 cm telescope aperture. This edge filter with a multi-frequency lidar concept can be applied to other direct-detection Doppler lidars for profiling both wind and temperature simultaneously from the lower to the upper atmosphere.

  8. External-RBS, PIXE and NRA analysis for ancient swords

    NASA Astrophysics Data System (ADS)

    Santos, Hellen C.; Added, Nemitala; Silva, Tiago F.; Rodrigues, C. L.

    2015-02-01

    Elemental composition of the steel of two ancient swords (Japanese and Damascus from a private collection) was characterized using in air IBA techniques. Our results contribute for the understanding the processes of manufacturing (hammering and quenching) and surface treatments applied in these swords. The Particle Induced X-ray Emission (PIXE) measurements along the Damascus blade allowed to identify and to trace a superficial concentration profile for the elements such Cr, Mn, Fe, Ni, Cu, Zn and As, while results for the Japanese blade showed only the presence of iron. The carbon content on the surface was also investigated using a resonant region in the Elastic Backscattering Spectrometry (EBS) measurements and the results have shown a slightly difference between the surfaces under investigation. In order to investigate the nitrogen content on surface, that could explain the hardening process, we used Nuclear Reaction Analysis (NRA) and the results shown that nitrogen content was under our detection limit for the technique (0.3% in mass). The measurements of PIXE, NRA and EBS were taken using the external beam setup installed at Lamfi - São Paulo/Brazil, the latter being successfully implemented for the first time in this facility.

  9. Double-Edged Roles of Nitric Oxide Signaling on APP Processing and Amyloid-β Production In Vitro: Preliminary Evidence from Sodium Nitroprusside.

    PubMed

    Cai, Zheng-Xu; Guo, Hui-Shu; Wang, Che; Wei, Min; Cheng, Cheng; Yang, Zhao-Fei; Chen, Yin-Wang; Le, Wei-Dong; Li, Song

    2016-01-01

    Alzheimer's disease (AD) is a progressive neurodegenerative disorder that is thought to be caused in part by the age-related accumulation of amyloid-β (Aβ) in the brain. Recent findings have revealed that nitric oxide (NO) modulates the processing of amyloid-β precursor protein (APP) and alters Aβ production; however, the previously presented data are contradictory and the underlying molecular mechanisms are still incomplete. Here, using human SH-SY5Y neuroblastoma cells stably transfected with wild-type APPwt695, we found that NO, derived from NO donor sodium nitroprusside (SNP), bi-directionally modulates APP processing in vitro. The data from ELISA and Western blot (WB) tests indicated that SNP at lower concentrations (0.01 and 0.1 μM) inhibits BACE1 expression, thus consequently suppresses APP β-cleavage and decreases Aβ production. In contrast, SNP at higher concentrations (10 and 20 μM) biases the APP processing toward the amyloidogenic pathway as evidenced by an increased BACE1 but a decreased ADAM10 expression, together with an elevated Aβ secretion. This bi-directional modulating activity of SNP on APP processing was completely blocked by specific NO scavenger c-PTIO, indicating NO-dependent mechanisms. Moreover, the anti-amyloidogenic activity of SNP is sGC/cGMP/PKG-dependent as evidenced by its reversal by sGC/PKG inhibitions, whereas the amyloidogenic activity of SNP is peroxynitrite-related and can be reversed by peroxynitrite scavenger uric acid. In summary, these present findings predict a double-edged role of NO in APP processing in vitro. Low (physiological) levels of NO inhibit the amyloidogenic processing of APP, whereas extra-high (pathological) concentrations of NO favor the amyloidogenic pathway of APP processing. This preliminary study may provide further evidence to clarify the molecular roles of NO and NO-related signaling in AD and supply potential molecular targets for AD treatment.

  10. Comparing signal intensity and refraction sensitivity of double and single mask edge illumination lab-based x-ray phase contrast imaging set-ups

    NASA Astrophysics Data System (ADS)

    Kallon, G. K.; Diemoz, P. C.; Vittoria, F. A.; Basta, D.; Endrizzi, M.; Olivo, A.

    2017-10-01

    Double mask edge illumination (DM-EI) set-ups can detect differential phase and attenuation information from a sample. However, analytical separation of the two signals often requires acquiring two frames with inverted differential phase contrast signals. Typically, between these two acquisitions, the first mask is moved to create a different illumination condition. This can lead to potential errors which adversely affect the data collected. In this paper, we implement a single mask EI laboratory set-up that allows for a single shot retrieval of the differential phase and attenuation images, without the need for a high resolution detector or high magnification. As well as simplifying mask alignment, the advantages of the proposed set-up can be exploited in one of two ways: either the total acquisition time can be halved with respect to the DM-EI set-up or, for the same acquisition time, twice the statistics can be collected. In this latter configuration, the signal-to-noise ratio and contrast in the mixed intensity images, and the angular sensitivity of the two set-ups were compared. We also show that the angular sensitivity of the single mask set-up can be well approximated from its illumination curve, which has been modelled as a convolution between the source spatial distribution at the detector plane, the pre-sample mask and the detector point spread function (PSF). A polychromatic wave optics simulation was developed on these bases and benchmarked against experimental data. It can also be used to predict the angular sensitivity and contrast of any set-up as a function of detector PSF.

  11. The evolution of the sexually selected sword in Xiphophorus does not compromise aerobic locomotor performance.

    PubMed

    Oufiero, Christopher E; Meredith, Robert W; Jugo, Kristine N; Tran, Paulina; Chappell, Mark A; Springer, Mark S; Reznick, David N; Garland, Theodore

    2014-06-01

    Sexual selection can increase morphological diversity within and among species. Little is known regarding how interspecific variation produced through sexual selection affects other functional systems. Here, we examine how morphological diversity resulting from sexual selection impacts aerobic locomotor performance. Using Xiphophorus (swordtail fish) and their close relatives (N = 19 species), we examined whether the evolution of a longer sexually selected sword affects critical swimming speed. We also examined the effect of other suborganismal, physiological, and morphological traits on critical swimming speed, as well as their relationship with sword length. In correlation analyses, we found no significant relationship between sword length and critical swimming speed. Unexpectedly, we found that critical swimming speed was higher in species with longer swords, after controlling for body size in multiple regression analyses. We also found several suborganismal and morphological predictors of critical swimming speed, as well as a significant negative relationship between sword length and heart and gill mass. Our results suggest that interspecific variation in sword length is not costly for this aspect of swimming performance, but further studies should examine potential costs for other types of locomotion and other components of Darwinian fitness (e.g., survivorship, life span).

  12. CHANG-ES. III. UGC 10288—An edge-on galaxy with a background double-lobed radio source

    SciTech Connect

    Irwin, Judith; Krause, Marita; Beck, Rainer; English, Jayanne; Murphy, Eric; Wiegert, Theresa; Heald, George; Walterbos, Rene; Rand, Richard J.; Porter, Troy E-mail: mkrause@mpifr-bonn.mpg.de E-mail: jayanne_english@umanitoba.ca E-mail: twiegert@astro.queensu.ca E-mail: rwalterb@nmsu.edu E-mail: tporter@stanford.edu

    2013-12-01

    This third paper in the Continuum Halos in Nearby Galaxies—an EVLA Survey (CHANG-ES) series shows the first results from our regular data taken with the Karl G. Jansky Very Large Array. The edge-on galaxy, UGC 10288, has been observed in the B, C, and D configurations at L band (1.5 GHz) and in the C and D configurations at C band (6 GHz) in all polarization products. We show the first spatially resolved images of this galaxy in these bands, the first polarization images, and the first composed image at an intermediate frequency (4.1 GHz) which has been formed from a combination of all data sets. A surprising new result is the presence of a strong, polarized, double-lobed extragalactic radio source (CHANG-ES A) almost immediately behind the galaxy and perpendicular to its disk. The core of CHANG-ES A has an optical counterpart (SDSS J161423.28–001211.8) at a photometric redshift of z {sub phot} = 0.39; the southern radio lobe is behind the disk of UGC 10288 and the northern lobe is behind the halo region. This background ''probe'' has allowed us to do a preliminary Faraday rotation analysis of the foreground galaxy, putting limits on the regular magnetic field and electron density in the halo of UGC 10288 in regions in which there is no direct detection of a radio continuum halo. We have revised the flux densities of the two sources individually as well as the star formation rate (SFR) for UGC 10288. The SFR is low (0.4-0.5 M {sub ☉} yr{sup –1}) and the galaxy has a high thermal fraction (44% at 6 GHz), as estimated using both the thermal and non-thermal SFR calibrations of Murphy et al. UGC 10288 would have fallen well below the CHANG-ES flux density cutoff, had it been considered without the brighter contribution of the background source. UGC 10288 shows discrete high-latitude radio continuum features, but it does not have a global radio continuum halo (exponential scale heights are typically ≈1 kpc averaged over regions with and without extensions

  13. Breaking Tolerance in Transgenic Mice Expressing the Human TSH Receptor A-Subunit: Thyroiditis, Epitope Spreading and Adjuvant as a ‘Double Edged Sword’

    PubMed Central

    McLachlan, Sandra M.; Aliesky, Holly A.; Chen, Chun-Rong; Chong, Gao; Rapoport, Basil

    2012-01-01

    Transgenic mice with the human thyrotropin-receptor (TSHR) A-subunit targeted to the thyroid are tolerant of the transgene. In transgenics that express low A-subunit levels (Lo-expressors), regulatory T cell (Treg) depletion using anti-CD25 before immunization with adenovirus encoding the A-subunit (A-sub-Ad) breaks tolerance, inducing extensive thyroid lymphocytic infiltration, thyroid damage and antibody spreading to other thyroid proteins. In contrast, no thyroiditis develops in Hi-expressor transgenics or wild-type mice. Our present goal was to determine if thyroiditis could be induced in Hi-expressor transgenics using a more potent immunization protocol: Treg depletion, priming with Complete Freund's Adjuvant (CFA) + A-subunit protein and further Treg depletions before two boosts with A-sub-Ad. As controls, anti-CD25 treated Hi- and Lo-expressors and wild-type mice were primed with CFA+ mouse thyroglobulin (Tg) or CFA alone before A-sub-Ad boosting. Thyroiditis developed after CFA+A-subunit protein or Tg and A-sub-Ad boosting in Lo-expressor transgenics but Hi- expressors (and wild-type mice) were resistant to thyroiditis induction. Importantly, in Lo-expressors, thyroiditis was associated with the development of antibodies to the mouse TSHR downstream of the A-subunit. Unexpectedly, we observed that the effect of bacterial products on the immune system is a “double-edged sword”. On the one hand, priming with CFA (mycobacteria emulsified in oil) plus A-subunit protein broke tolerance to the A-subunit in Hi-expressor transgenics leading to high TSHR antibody levels. On the other hand, prior treatment with CFA in the absence of A-subunit protein inhibited responses to subsequent immunization with A-sub-Ad. Consequently, adjuvant activity arising in vivo after bacterial infections combined with a protein autoantigen can break self-tolerance but in the absence of the autoantigen, adjuvant activity can inhibit the induction of immunity to autoantigens (like the

  14. Microstructural Features in Corroded Celtic Iron Age Sword Blades

    NASA Astrophysics Data System (ADS)

    Ghiara, G.; Piccardo, P.; Campodonico, S.; Carnasciali, M. M.

    2014-05-01

    Archaeological artefacts made from iron and steel are often of critical importance for archaeometallurgical studies, which aim to understand the process of manufacturing, as the nearly complete alloy mineralization does not allow for any type of metallographic interpretation. In this study, three Iron Age sword blades dated from the second century BC (LaTène B2/D1) found in the archaeological site of Tintignac (Commune de Naves, Corrèze, France), were investigated. A multianalytical approach was employed to acquire a complete range of data from the partially or totally corroded objects. Analyses were carried out with the use of light optical microscopy, micro Raman spectroscopy, and scanning electron microscopy equipped with energy-dispersive x-ray spectroscopy (EDXS). Remnants of metallographic features—ghost microstructure—in the corrosion layers of the blades were observed, allowing for a partial reconstruction of the manufacturing process.

  15. A comparison of antioxidative and anti-inflammatory activities of sword beans and soybeans fermented with Bacillus subtilis.

    PubMed

    Han, Seon Su; Hur, Sun Jin; Lee, Si Kyung

    2015-08-01

    This study was conducted to determine the antioxidative and anti-inflammatory activities of non-fermented or Bacillus subtilis-fermented soybeans and sword beans (red and white). The total flavonoid content in both sword bean types was higher (1.9-2.5-fold) than that in soybeans. The total phenolic content in fermented red sword beans was 2.5-fold greater than that in non-fermented red sword beans. HPLC profiles revealed that gallic acid, methyl gallate, and ellagic acid were major phenolic components of non-fermented/fermented red sword beans. DPPH radical scavenging activity and ferric-reducing antioxidant power were higher in fermented red sword beans than in other beans. Non-fermented/fermented red sword beans had higher nitrite scavenging activity than butylated hydroxytoluene and non-fermented/fermented soybeans. The hyaluronidase inhibitory activity of non-fermented/fermented red sword beans was higher (1.5-2.6-fold) than that of non-fermented/fermented soybeans. These results suggest that B. subtilis-fermented sword beans are potential natural antioxidant sources and anti-inflammatory agents for the food industry.

  16. The blunt-edged sword: genetic explanations of misbehavior neither mitigate nor aggravate punishment

    PubMed Central

    Scurich, Nicholas; Appelbaum, Paul

    2015-01-01

    Links between genetic variants and negatively valenced behaviors have stimulated intense commentary about the implications for responsibility and punishment. Previous research has suggested that behavioral genetic evidence of a predisposition to negative behaviors has modest to no impact on mitigation of punishment, at least for serious crimes. Data are presented on the effect of such evidence in a representative sample of the general population (n = 640) asked to consider three vignettes describing lesser offenses, dealt with in less formal adjudicatory settings and in everyday life. Genetic explanations of behavior had no effect on the severity of the punishment selected in any case, in contrast to the egregiousness of the behavior and respondents’ beliefs in free-will. Public views of genetic influences on behavior may be less deterministic and more nuanced than is often thought, or genetic explanations may simply not have the salience for decision makers that is frequently attributed to them. PMID:27239327

  17. My Patient, My Stalker Empathy as a Dual-Edged Sword: A Cautionary Tale.

    PubMed

    Farber, Sharon K

    2015-01-01

    Success in psychotherapy is correlated with the "fit" between patient and therapist, a factor related to attachment. For psychotherapists of any orientation, empathy and building the bond of attachment is our stock-in-trade. When empathy builds the bond of attachment with someone starved for connection, a therapist may inadvertently set him- or herself up to become a victim of a stalker. Because individuals who stalk others suffer from severe attachment disorders, their hunger for attachment motivates them to shadow psychotherapists, which makes being stalked a very real occupational hazard for psychotherapists. This was a painful discovery for me. I was stalked for 11 months, leaving me with post-traumatic stress disorder. After recovering, I deconstructed the experience to understand how and why it happened, and discovered that it was my empathy and compassion that contributed to and maintained the stalking. What I learned from the forensic literature provided the knowledge and confidence needed to end the stalking. In this paper recommendations are made about how to prevent stalking and to halt it if it does happens.

  18. Bibliometrics and social work: a two-edged sword can still be a blunt instrument.

    PubMed

    Ligon, Jan; Thyer, Bruce A

    2005-01-01

    In order to improve the productivity and impact of social work scholarship, the profession must look beyond bibliometrics to other issues that must be considered. These include the lag time between acceptance and publication of articles, the quality of peer review experienced by social work authors, and the overabundance of journals being published in social work.

  19. Pro- and anti-inflammatory cytokines in tuberculosis: a two-edged sword in TB pathogenesis.

    PubMed

    Etna, Marilena Paola; Giacomini, Elena; Severa, Martina; Coccia, Eliana Marina

    2014-12-01

    A major challenge in tuberculosis (TB) is to improve current vaccination and therapeutic strategies and this requires a fine understanding of the mechanisms that mediate protection and pathogenesis. We need to discern how the host perceives Mycobacterium tuberculosis (Mtb) infection, what are the danger signals that activate the immune system and, in turn, how the immune response controls the life-cycle of Mtb. Cytokines, because of their nature of soluble mediators, represent key elements in mediating and tuning these complex processes. In this review, we provide an overview of recent studies on cytokines expression and function in active (mainly human) TB. Understanding of the balance between pro- and anti-inflammatory networks is crucial to refine our knowledge on the immune responses directed against Mtb. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Fgfr1 signalling in the development of a sexually selected trait in vertebrates, the sword of swordtail fish

    PubMed Central

    Offen, Nils; Blum, Nicola; Meyer, Axel; Begemann, Gerrit

    2008-01-01

    Background One of Darwin's chosen examples for his idea of sexual selection through female choice was the "sword", a colourful extension of the caudal fin of male swordtails of the genus Xiphophorus. Platyfish, also members of the genus Xiphophorus, are thought to have arisen from within the swordtails, but have secondarily lost the ability to develop a sword. The sustained increase of testosterone during sexual maturation initiates sword development in male swordtails. Addition of testosterone also induces sword-like fin extensions in some platyfish species, suggesting that the genetic interactions required for sword development may be dormant, rather than lost, within platyfish. Despite considerable interest in the evolution of the sword from a behavioural or evolutionary point of view, little is known about the developmental changes that resulted in the gain and secondary loss of the sword. Up-regulation of msxC had been shown to characterize the development of both swords and the gonopodium, a modified anal fin that serves as an intromittent organ, and prompted investigations of the regulatory mechanisms that control msxC and sword growth. Results By comparing both development and regeneration of caudal fins in swordtails and platyfish, we show that fgfr1 is strongly up-regulated in developing and regenerating sword and gonopodial rays. Characterization of the fin overgrowth mutant brushtail in a platyfish background confirmed that fin regeneration rates are correlated with the expression levels of fgfr1 and msxC. Moreover, brushtail re-awakens the dormant mechanisms of sword development in platyfish and activates fgfr1/msxC-signalling. Although both genes are co-expressed in scleroblasts, expression of msxC in the distal blastema may be independent of fgfr1. Known regulators of Fgf-signalling in teleost fins, fgf20a and fgf24, are transiently expressed only during regeneration and thus not likely to be required in developing swords. Conclusion Our data suggest

  1. If SWORD Is the Answer, What Is the Question?: Use of the Simple Web-Service Offering Repository Deposit Protocol

    ERIC Educational Resources Information Center

    Lewis, Stuart; Hayes, Leonie; Newton-Wade, Vanessa; Corfield, Antony; Davis, Richard; Donohue, Tim; Wilson, Scott

    2009-01-01

    Purpose: The purpose of this paper is to describe the repository deposit protocol, Simple Web-service Offering Repository Deposit (SWORD), its development iteration, and some of its potential use cases. In addition, seven case studies of institutional use of SWORD are provided. Design/methodology/approach: The paper describes the recent…

  2. Key contributors for improvement of line width roughness, line edge roughness, and critical dimension uniformity: 15 nm half-pitch patterning with extreme ultraviolet and self-aligned double patterning

    NASA Astrophysics Data System (ADS)

    Xu, Kaidong; Souriau, Laurent; Hellin, David; Versluijs, Janko; Wong, Patrick; Vangoidsenhoven, Diziana; Vandenbroeck, Nadia; Dekkers, Harold; Shi, Xiaoping; Albert, Johan; Tan, Chi Lim; Vertommen, Johan; Coenegrachts, Bart; Orain, Isabelle; Kimura, Yoshie; Wiaux, Vincent; Boullart, Werner

    2013-10-01

    The approach for patterning 15-nm half-pitch (HP) structures using extreme ultraviolet lithography combined with self-aligned double patterning is discussed. A stack composed of a double hard mask, which allows decoupling photoresist transfer and trim, and an α-Si mandrel, which offers better mechanical properties during the mandrel and spacer patterning, is proposed. A break-down study with the patterning steps was performed to investigate the key contributors for improvement of linewidth roughness (LWR), line-edge roughness (LER), and critical dimension uniformity (CDU), targeting integrated solutions with lithography, etch, thin film deposition, and wet cleans for selected applications. Based on the optimization of these key patterning contributors, optimum LWR, LER, and CDU at 15 nm HP are demonstrated.

  3. Compensation of Presbyopia With the Light Sword Lens.

    PubMed

    Mira-Agudelo, Alejandro; Torres-Sepúlveda, Walter; Barrera, John F; Henao, Rodrigo; Blocki, Narcyz; Petelczyc, Krzysztof; Kolodziejczyk, Andrzej

    2016-12-01

    We present the first physiological evaluation of the use of the light sword lens (LSL) for presbyopia compensation. The LSL is an axially asymmetric optical element designed for imaging with extended depth of focus. A monocular visual simulator setup is implemented to measure visual acuity (VA). Physiological presbyopia is "mimicked" in human subjects by paralysis of the ciliary muscle, using topical application of a muscarinic antagonist. The effect of a contact lens-configured LSL on the mimicked presbyopia visual system is evaluated by measuring VA as a function of target vergence. The ability of the LSL to compensate presbyopia for 2 photopic luminance values was also analyzed. The average VA values for 11 subjects suggest that the LSL can compensate for presbyopia across a wide range of target vergences for which the LSL was designed (-3 to 0 D). However, the proposed corrector element causes a loss of distance VA. The mean logMAR VA in that target vergence range was 0.07. The VA curves also show that luminance does not affect the expected behavior of the LSL-corrected presbyopic eye. These results indicate that the LSL has significant potential as a visual aid for presbyopia.

  4. Imaging properties of the light sword optical element

    NASA Astrophysics Data System (ADS)

    Zemlo, P.; Sypek, Maciej; Kolodziejczyk, Andrzej; Jaroszewicz, Zbigniew

    1994-10-01

    The Light Sword Optical Element (LSOE) is a diffractive structure focusing light into a fragment of the optical axis. An interesting property of the LSOE is its ability for imaging with extended depth of field. Optical Transfer Function (OTF) and Point Spread Function (PSF) are usually applied for description of imaging arrangements. During our investigations several binary phase LSOE structures were fabricated. The structures differ each other with their modulation factor and apertures. A typical main focal length was equal to 74 mm in a case of coherent He-Ne laser illumination of LSOEs. Aperture diameter belonged to the range [2.8 mm, 5.5 mm], the modulation factor varied from 10% to 40% of the main focal length. Each structure was analyzed in the optical system as well as by computer simulation. PSFs of LSOE structures were measured in the optical system and were calculated numerically. Modulated Transfer Functions (MTFs) were calculated on the base of calculated and measured PSFs. Theoretical and experimental results were compared and discussed. Moreover, the experimental and numerical analysis of the Siemens star imaging was performed.

  5. Tameshi-giri, or Japanese sword test-cutting: a historic overview.

    PubMed

    Kremer, Célia; Racette, Stéphanie; Schellenberg, Morgan; Chaltchi, Amir; Sauvageau, Anny

    2008-03-01

    The martial Japanese history is characterized by the development of a particular samurai sword known as the katana. It was believed that this sword was the reflection of the warrior's soul, and thus it had to be tested to estimate its sharpness, efficiency, and cutting ability. A variety of cutting tests was done on animals and bamboos, but some were also carried out on human beings. This technique was called tameshi-giri. Although the practice on human beings has since disappeared, the remaining cutting test records represent precious information about human body's resistance to sharp weapons.

  6. The Orion Nebula: The Jewel in the Sword

    NASA Astrophysics Data System (ADS)

    2001-01-01

    Orion the Hunter is perhaps the best known constellation in the sky, well placed in the evening at this time of the year for observers in both the northern and southern hemispheres, and instantly recognisable. And for astronomers, Orion is surely one of the most important constellations, as it contains one of the nearest and most active stellar nurseries in the Milky Way, the galaxy in which we live. Here tens of thousands of new stars have formed within the past ten million years or so - a very short span of time in astronomical terms. For comparison: our own Sun is now 4,600 million years old and has not yet reached half-age. Reduced to a human time-scale, star formation in Orion would have been going on for just one month as compared to the Sun's 40 years. Just below Orion's belt, the hilt of his sword holds a great jewel in the sky, the beautiful Orion Nebula . Bright enough to be seen with the naked eye, a small telescope or even binoculars show the nebula to be a few tens of light-years' wide complex of gas and dust, illuminated by several massive and hot stars at its core, the famous Trapezium stars . However, the heart of this nebula also conceals a secret from the casual observer. There are in fact about one thousand very young stars about one million years old within the so-called Trapezium Cluster , crowded into a space less than the distance between the Sun and its nearest neighbour stars. The cluster is very hard to observe in visible light, but is clearly seen in the above spectacular image of this area ( ESO PR 03a/01 ), obtained in December 1999 by Mark McCaughrean (Astrophysical Institute Potsdam, Germany) and his collaborators [1] with the infrared multi-mode ISAAC instrument on the ESO Very Large Telescope (VLT) at Paranal (Chile). Many details are seen in the new ISAAC image ESO PR Photo 03b/01 ESO PR Photo 03b/01 [Preview - JPEG: 400 x 589 pix - 62k] [Normal - JPEG: 800 x 1178 pix - 648k] [Hires - JPEG: 1957 x 2881 pix - 2.7M] ESO PR Photo 03c

  7. Is the sword moss (Bryoxiphium) a preglacial Tertiary relict?

    PubMed

    Patiño, Jairo; Goffinet, Bernard; Sim-Sim, Manuela; Vanderpoorten, Alain

    2016-03-01

    The disjunction of floras between East Asia, Southeast North America, West North America, and Southwest Eurasia has been interpreted in terms of the fragmentation of a once continuous mixed mesophytic forest that occurred throughout the Northern Hemisphere due to the climatic and geological changes during the late Tertiary. The sword moss, Bryoxiphium, exhibits a distribution that strikingly resembles that of the mesophytic forest elements such as Liriodendron and is considered as the only living member of an early Tertiary flora in Iceland. These hypotheses are tested here using molecular dating analyses and ancestral area estimations. The results suggest that the extant range of Bryoxiphium results from the fragmentation of a formerly wider range encompassing North America and Southeast Asia about 10 million years ago. The split of continental ancestral populations is too recent to match with a continental drift scenario but is spatially and temporally remarkably congruent with that observed in Tertiary angiosperm relict species. The timing of the colonization of Iceland from Macaronesian ancestors, about two million years ago, is, however, incompatible with the hypothesis that Bryoxiphium is the only living member of an early Tertiary flora of the island. Alaska was recurrently colonized from East Asia. The ability of Bryoxiphium to overcome large oceanic barriers is further evidenced by its occurrence on remote oceanic archipelagos. In particular, Madeira was colonized twice independently from American and East Asian ancestors, respectively. The striking range disjunction of Bryoxiphium is interpreted in terms of its mating system, as the taxon exhibits a very singular pattern of spatial segregation of the sexes.

  8. The Effects of Negative Differential Resistance, Bipolar Spin-Filtering, and Spin-Rectifying on Step-Like Zigzag Graphene Nanoribbons Heterojunctions with Single or Double Edge-Saturated Hydrogen

    NASA Astrophysics Data System (ADS)

    Wang, Lihua; Zhao, Jianguo; Ding, Bingjun; Guo, Yong

    2017-01-01

    In this study, we investigated the spin-resolved transport aspects of step-like zigzag graphene ribbons (ZGNRs) with single or double edge-saturated hydrogen using a method that combined the density functional theory with the nonequilibrium Green's function method under the local spin density approximation. We found that, when the ZGNR-based heterojunctions were in a parallel or antiparallel layout, negative differential resistance, the maximum bipolar spin-filtering, and spin-rectifying effects occurred synchronously except for the case of spin-down electrons in the parallel magnetic layouts. Interestingly, these spin-resolved transport properties were almost unaffected by altering the widths of the two component ribbons. Therefore, step-like ZGNR heterojunctions are promising for use in designing high-performance multifunctional spintronic devices.

  9. Nb K-edge x-ray absorption investigation of the pressure induced amorphization in A-site deficient double perovskite La1/3NbO3.

    PubMed

    Marini, C; Noked, O; Kantor, I; Joseph, B; Mathon, O; Shuker, R; Kennedy, B J; Pascarelli, S; Sterer, E

    2016-02-03

    Nb K-edge x-ray absorption spectroscopy is utilized to investigate the changes in the local structure of the A-site deficient double perovskite La1/3NbO3 which undergoes a pressure induced irreversible amorphization. EXAFS results show that with increasing pressure up to 7.5 GPa, the average Nb-O bond distance decreases in agreement with the expected compression and tilting of the NbO6 octahedra. On the contrary, above 7.5 GPa, the average Nb-O bond distance show a tendency to increase. Significant changes in the Nb K-edge XANES spectrum with evident low energy shift of the pre-peak and the absorption edge is found to happen in La1/3NbO3 above 6.3 GPa. These changes evidence a gradual reduction of the Nb cations from Nb(5+) towards Nb(4+) above 6.3 GPa. Such a valence change accompanied by the elongation of the average Nb-O bond distances in the octahedra, introduces repulsion forces between non-bonding adjacent oxygen anions in the unoccupied A-sites. Above a critical pressure, the Nb reduction mechanism can no longer be sustained by the changing local structure and amorphization occurs, apparently due to the build-up of local strain. EXAFS and XANES results indicate two distinct pressure regimes having different local and electronic response in the La1/3NbO3 system before the occurence of the pressure induced amorphization at  ∼14.5 GPa.

  10. Nb K-edge x-ray absorption investigation of the pressure induced amorphization in A-site deficient double perovskite La1/3NbO3

    NASA Astrophysics Data System (ADS)

    Marini, C.; Noked, O.; Kantor, I.; Joseph, B.; Mathon, O.; Shuker, R.; Kennedy, B. J.; Pascarelli, S.; Sterer, E.

    2016-02-01

    Nb K-edge x-ray absorption spectroscopy is utilized to investigate the changes in the local structure of the A-site deficient double perovskite La1/3NbO3 which undergoes a pressure induced irreversible amorphization. EXAFS results show that with increasing pressure up to 7.5 GPa, the average Nb-O bond distance decreases in agreement with the expected compression and tilting of the NbO6 octahedra. On the contrary, above 7.5 GPa, the average Nb-O bond distance show a tendency to increase. Significant changes in the Nb K-edge XANES spectrum with evident low energy shift of the pre-peak and the absorption edge is found to happen in La1/3NbO3 above 6.3 GPa. These changes evidence a gradual reduction of the Nb cations from Nb5+ towards Nb4+ above 6.3 GPa. Such a valence change accompanied by the elongation of the average Nb-O bond distances in the octahedra, introduces repulsion forces between non-bonding adjacent oxygen anions in the unoccupied A-sites. Above a critical pressure, the Nb reduction mechanism can no longer be sustained by the changing local structure and amorphization occurs, apparently due to the build-up of local strain. EXAFS and XANES results indicate two distinct pressure regimes having different local and electronic response in the La1/3NbO3 system before the occurence of the pressure induced amorphization at  ˜14.5 GPa.

  11. Edge Bioinformatics

    SciTech Connect

    Lo, Chien-Chi

    2015-08-03

    Edge Bioinformatics is a developmental bioinformatics and data management platform which seeks to supply laboratories with bioinformatics pipelines for analyzing data associated with common samples case goals. Edge Bioinformatics enables sequencing as a solution and forward-deployed situations where human-resources, space, bandwidth, and time are limited. The Edge bioinformatics pipeline was designed based on following USE CASES and specific to illumina sequencing reads. 1. Assay performance adjudication (PCR): Analysis of an existing PCR assay in a genomic context, and automated design of a new assay to resolve conflicting results; 2. Clinical presentation with extreme symptoms: Characterization of a known pathogen or co-infection with a. Novel emerging disease outbreak or b. Environmental surveillance

  12. Electronic and Chemical State of Aluminum from the Single- (K) and Double-Electron Excitation (KLII&III, KLI) X-ray Absorption Near-Edge Spectra of α-Alumina, Sodium Aluminate, Aqueous Al(3+)·(H2O)6, and Aqueous Al(OH)4(-).

    PubMed

    Fulton, John L; Govind, Niranjan; Huthwelker, Thomas; Bylaska, Eric J; Vjunov, Aleksei; Pin, Sonia; Smurthwaite, Tricia D

    2015-07-02

    We probe, at high energy resolution, the double electron excitation (KLII&II) X-ray absorption region that lies approximately 115 eV above the main Al K-edge (1566 eV) of α-alumina and sodium aluminate. The two solid standards, α-alumina (octahedral) and sodium aluminate (tetrahedral), are compared to aqueous species that have the same Al coordination symmetries, Al(3+)·6H2O (octahedral) and Al(OH)4(-) (tetrahedral). For the octahedral species, the edge height of the KLII&III-edge is approximately 10% of the main K-edge; however, the edge height is much weaker (3% of K-edge height) for Al species with tetrahedral symmetry. For the α-alumina and aqueous Al(3+)·6H2O the KLII&III spectra contain white line features and extended absorption fine structure (EXAFS) that mimics the K-edge spectra. The KLII&III-edge feature interferes with an important region in the EXAFS spectra of the crystalline and aqueous standards. The K-edge spectra and K-edge energy positions are predicted using time-dependent density functional theory (TDDFT). The TDDFT calculations for the K-edge X-ray absorption near-edge spectra (XANES) reproduce the observed transitions in the experimental spectra of the four Al species. The KLII&II and KLI onsets and their corresponding chemical shifts for the four standards are estimated using the delta self-consistent field (ΔSCF) method.

  13. A novel algorithm for the edge detection and edge enhancement of medical images.

    PubMed

    Crooks, I; Fallone, B G

    1993-01-01

    A novel algorithm, histogram shifting (HS) is presented, which performs edge detection or edge enhancement with the choice of two parameters. The histogram of a region surrounding each pixel is found and translated toward the origin, resulting in the new pixel value. Images from a variety of medical imaging modalities were processed with HS to perform detection and enhancement of edges. Comparison with results obtained from conventional edge detection (e.g., Sobel) and with conventional edge-enhancement algorithms is discussed. HS appears to perform the edge-detection operation without introducing "double-edge" effects often obtained with conventional edge-detection algorithms. HS also appears to perform edge enhancement without introducing extensive noise artifacts, which may be noticeable with many edge-enhancement algorithms.

  14. Determining the Causes of Erectile Dysfunction: Can Medications be a Double-Sided Sword?

    PubMed

    Williams, La Vonn A

    2010-01-01

    Like other medical problems, diagnosing the causes of erectile dysfunction requires a series of tests, as well as trial and error. The possibility that side effects to a patient's medications may be one of the causes of erectile dysfunction is discussed often in published articles. Physicians are aware that in order to diagnose a physiological problem, the simplest causes for the problem should be considered and eliminated first. Therefore, the physician should review a patient's list of medications as first protocol. This article lists some of the more common causes of erectile dysfunction and provides a list of drugs that are linked to erectile dysfunction. Compounding pharmacists should be involved in the treatment of this physiological/psychological condition to offer private consultations and alternative medications to those patients who can't or shouldn't take certain manufactured drugs that may cause erectile dysfunction or, because of certain risks, drugs that are sold to treat erectile dysfunction.

  15. Reversible changes of canavalin solubility controlled by divalent cation concentration in crude sword bean extract.

    PubMed

    Nishizawa, Kaho; Arii, Yasuhiro

    2016-12-01

    Canavalin is a vicilin-class (7S) storage protein found in sword bean (Canavalia gladiata). Our previous report indicated that canavalin is precipitated by the addition of 20 mM MgCl2 to crude sword bean extract. Here, we examined the solubility changes induced by the addition of Mg(2+) and Ca(2+) at various concentrations. Canavalin tended to be insolubilized at relatively low concentrations of MgCl2 (< 20 mM) and solubilized at relatively high concentrations (> 20 mM). In addition, canavalin was slightly insolubilized in the presence of NaCl. Overall, the results revealed that solubility changes are reversible and depend on the concentration of divalent cations. Therefore, we suggested a reaction scheme that describes the effects of divalent cations on the solubility of canavalin, which would facilitate the study of its physiological function and the application of canavalin in the food processing industry.

  16. Sword-Like Trauma to the Shoulder with Open Head-Splitting Fracture of the Head

    PubMed Central

    Pantazis, Konstantinos; Iliopoulos, Ilias; Seferlis, Ioannis; Kokkalis, Zinon

    2016-01-01

    Head-splitting fractures occur as a result of violent compression of the head against the glenoid; the head splits and the tuberosities may remain attached to the fragments or split and separate. Isolated humeral head-splitting fractures are rare injuries. Favorable results with osteosynthesis can be difficult to achieve because of the very proximal location of the head fracture and associated poor vascularity. We present a case of a 67-year-old man who sustained a severe, sword-like trauma to his left shoulder after a road traffic accident with associated isolated open Gustilo-Anderson IIIA humeral head-splitting fracture. Bony union was achieved with minimal internal fixation but the clinical outcome deteriorated due to accompanying axillary nerve apraxia. To our knowledge, this type of sword-like injury with associated humeral head-split fracture has not previously been reported. PMID:27478665

  17. SoftWare for Optimization of Radiation Detectors, SWORD Version 5.0.

    SciTech Connect

    STRICKMAN, MARK S.

    2013-10-23

    Version 05 SoftWare for Optimization of Radiation Detectors (SWORD) is a framework to allow easy simulation and evaluation of radiation detection systems. It is targeted at system designers, who want to evaluate and optimize system parameters without actually building hardware first, at sponsors who need to evaluate proposed or actual system designs independent of the supplier, without having access to actual hardware, and at operators who want to use simulation to evaluate observed phenomena. SWORD is vertically integrated and modular. It allows users to define their own radiation detection instruments by building them from basic geometric “objects” and assigning those objects materials, detection, and/or radioactive emission properties. This process is accomplished by a CAD-like graphical user interface, in which objects may be defined, translated, rotated, grouped, arrayed, and/or nested to produce compound objects. In addition to providing the ability to build a detection system model from scratch, SWORD provides a library of “standard” detector design objects that can be used “as is” or modified by the user.

  18. Sulfur and iron accumulation in three marine-archaeological shipwrecks in the Baltic Sea: The Ghost, the Crown and the Sword

    PubMed Central

    Fors, Yvonne; Grudd, Håkan; Rindby, Anders; Jalilehvand, Farideh; Sandström, Magnus; Cato, Ingemar; Bornmalm, Lennart

    2014-01-01

    Sulfur and iron concentrations in wood from three 17th century shipwrecks in the Baltic Sea, the Ghost wreck, the Crown and the Sword, were obtained by X-ray fluorescence (XRF) scanning. In near anaerobic environments symbiotic microorganisms degrade waterlogged wood, reduce sulfate and promote accumulation of low-valent sulfur compounds, as previously found for the famous wrecks of the Vasa and Mary Rose. Sulfur K-edge X-ray absorption near-edge structure (XANES) analyses of Ghost wreck wood show that organic thiols and disulfides dominate, together with elemental sulfur probably generated by sulfur-oxidizing Beggiatoa bacteria. Iron sulfides were not detected, consistent with the relatively low iron concentration in the wood. In a museum climate with high atmospheric humidity oxidation processes, especially of iron sulfides formed in the presence of corroding iron, may induce post-conservation wood degradation. Subject to more general confirmation by further analyses no severe conservation concerns are expected for the Ghost wreck wood. PMID:24573214

  19. Sulfur and iron accumulation in three marine-archaeological shipwrecks in the Baltic Sea: the Ghost, the Crown and the Sword.

    PubMed

    Fors, Yvonne; Grudd, Håkan; Rindby, Anders; Jalilehvand, Farideh; Sandström, Magnus; Cato, Ingemar; Bornmalm, Lennart

    2014-02-27

    Sulfur and iron concentrations in wood from three 17(th) century shipwrecks in the Baltic Sea, the Ghost wreck, the Crown and the Sword, were obtained by X-ray fluorescence (XRF) scanning. In near anaerobic environments symbiotic microorganisms degrade waterlogged wood, reduce sulfate and promote accumulation of low-valent sulfur compounds, as previously found for the famous wrecks of the Vasa and Mary Rose. Sulfur K-edge X-ray absorption near-edge structure (XANES) analyses of Ghost wreck wood show that organic thiols and disulfides dominate, together with elemental sulfur probably generated by sulfur-oxidizing Beggiatoa bacteria. Iron sulfides were not detected, consistent with the relatively low iron concentration in the wood. In a museum climate with high atmospheric humidity oxidation processes, especially of iron sulfides formed in the presence of corroding iron, may induce post-conservation wood degradation. Subject to more general confirmation by further analyses no severe conservation concerns are expected for the Ghost wreck wood.

  20. Sulfur and iron accumulation in three marine-archaeological shipwrecks in the Baltic Sea: The Ghost, the Crown and the Sword

    NASA Astrophysics Data System (ADS)

    Fors, Yvonne; Grudd, Håkan; Rindby, Anders; Jalilehvand, Farideh; Sandström, Magnus; Cato, Ingemar; Bornmalm, Lennart

    2014-02-01

    Sulfur and iron concentrations in wood from three 17th century shipwrecks in the Baltic Sea, the Ghost wreck, the Crown and the Sword, were obtained by X-ray fluorescence (XRF) scanning. In near anaerobic environments symbiotic microorganisms degrade waterlogged wood, reduce sulfate and promote accumulation of low-valent sulfur compounds, as previously found for the famous wrecks of the Vasa and Mary Rose. Sulfur K-edge X-ray absorption near-edge structure (XANES) analyses of Ghost wreck wood show that organic thiols and disulfides dominate, together with elemental sulfur probably generated by sulfur-oxidizing Beggiatoa bacteria. Iron sulfides were not detected, consistent with the relatively low iron concentration in the wood. In a museum climate with high atmospheric humidity oxidation processes, especially of iron sulfides formed in the presence of corroding iron, may induce post-conservation wood degradation. Subject to more general confirmation by further analyses no severe conservation concerns are expected for the Ghost wreck wood.

  1. Edge Detection,

    DTIC Science & Technology

    1985-09-01

    PROJECT. T ASK0 Artificial Inteligence Laboratory AREA It WORK UNIT NUMBERS V 545 Technology Square ( Cambridge, HA 02139 I I* CONTOOL1LIN@4OFFICE NAME...ARD-A1t62 62 EDGE DETECTION(U) NASSACNUSETTS INST OF TECH CAMBRIDGE 1/1 ARTIFICIAL INTELLIGENCE LAB E C HILDRETH SEP 85 AI-M-8 N99SI4-8S-C-6595...used to carry out this analysis. cce~iO a N) ’.~" D LI’BL. P p ------------ Sj. t i MASSACHUSETTS INSTITUTE OF TECHNOLOGY i ARTIFICIAL INTELLIGENCE

  2. Non-destructive analysis of ancient bimetal swords from western Asia by γ-ray radiography and X-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Shizuma, Kiyoshi; Kajimoto, Tsuyoshi; Endo, Satoru; Matsugi, Kazuhiro; Arimatsu, Yui; Nojima, Hisashi

    2017-09-01

    Eight ancient bimetal swords held by Hiroshima University, Japan were analyzed non-destructively through γ-ray radiography and X-ray fluorescence (XRF). 137Cs and 60Co γ-ray irradiation sources were used to obtain transmission images of swords. A scanning radiography method using a 60Co γ-ray source was developed. XRF was used for qualitative elemental analysis of the swords. The presence of iron cores in the hilts of some swords had been observed and it was assumed that the cores were a ritual symbol or had a functional purpose. However, our work reveals that these swords were originally bronze-hilted iron swords and that the rusty blades were replaced with bronze blades to maintain the swords' commercial value as an antique. Consequently, the rest of the iron blade was left in the hilt as an iron tang. The junction of the blade and the guard was soldered and painted to match the patina color. XRF analysis clearly showed that the elemental Sn/Cu ratios of the blades and the hilts were different. These findings are useful for clarifying the later modifications of the swords and are important for interpreting Bronze Age and Iron Age history correctly.

  3. The Edge

    NASA Technical Reports Server (NTRS)

    2006-01-01

    6 April 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the edge (running diagonally from the lower left to the upper right) of a trough, which is part of a large pit crater complex in Noachis Terra. This type of trough forms through the collapse of surface materials into the subsurface, and often begins as a series of individual pit craters. Over time, continued collapse increases the diameter of individual pits until finally, adjacent pits merge to form a trough such as the one captured in this image. The deep shadowed area is caused in part by an overhang; layered rock beneath this overhang is less resistant to erosion, and thus has retreated tens of meters backward, beneath the overhang. A person could walk up inside this 'cave' formed by the overhanging layered material.

    Location near: 47.0oS, 355.7oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

  4. Transcription and DNA Damage: Holding Hands or Crossing Swords?

    PubMed

    D'Alessandro, Giuseppina; d'Adda di Fagagna, Fabrizio

    2016-11-05

    Transcription has classically been considered a potential threat to genome integrity. Collision between transcription and DNA replication machinery, and retention of DNA:RNA hybrids, may result in genome instability. On the other hand, it has been proposed that active genes repair faster and preferentially via homologous recombination. Moreover, while canonical transcription is inhibited in the proximity of DNA double-strand breaks, a growing body of evidence supports active non-canonical transcription at DNA damage sites. Small non-coding RNAs accumulate at DNA double-strand break sites in mammals and other organisms, and are involved in DNA damage signaling and repair. Furthermore, RNA binding proteins are recruited to DNA damage sites and participate in the DNA damage response. Here, we discuss the impact of transcription on genome stability, the role of RNA binding proteins at DNA damage sites, and the function of small non-coding RNAs generated upon damage in the signaling and repair of DNA lesions. Copyright © 2016. Published by Elsevier Ltd.

  5. Electronic and chemical state of aluminum from the single- (K) and double-electron excitation (KLII&III, KLI) x-ray absorption near-edge spectra of α-alumina, sodium aluminate, aqueous Al³⁺•(H₂O)₆, and aqueous Al(OH)₄⁻

    SciTech Connect

    Fulton, John L.; Govind, Niranjan; Huthwelker, Thomas; Bylaska, Eric J.; Vjunov, Aleksei; Pin, Sonia; Smurthwaite, Tricia D.

    2015-07-02

    We probe, at high energy resolution, the double electron excitation (KLII&II) x-ray absorption region that lies approximately 115 eV above the main Al K-edge (1566 eV) of α-alumina and sodium aluminate. The two solid standards, α-alumina (octahedral) and sodium aluminate (tetrahedral) are compared to aqueous species that have the same Al coordination symmetries, Al³⁺•6H₂O (octahedral) and Al(OH)₄⁻ (tetrahedral). For the octahedral species, the edge height of the KLII&III-edge is approximately 10% of the main K-edge however the edge height is much weaker (3% of K-edge height) for Al species with tetrahedral symmetry. For the α-alumina and aqueous Al³⁺•6H₂O the KLII&III spectra contain white line features and extended absorption fine structure (EXAFS) that mimics the K-edge spectra. The KLII&III-edge feature interferes with an important region of the extended-XAFS region of the spectra for the K-edge of the crystalline and aqueous standards. The K-edge spectra and K-edge positions are predicted using time-dependent density functional theory (TDDFT). The TDDFT calculations for the K-edge XANES spectra reproduce the observed transitions in the experimental spectra of the four Al species. The KLII&III and KLI onsets and their corresponding chemical shifts for the four standards are estimated using the delta self-consistent field (ΔSCF) method. Research by JLF, NG, EJB, AV, TDS was supported by U.S. Department of Energy’s (DOE), Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences. NG thanks Amity Andersen for help with the α-Al₂O₃ and tetrahedral sodium aluminate (NaAlO₂) clusters. All the calculations were performed using the Molecular Science Computing Capability at EMSL, a national scientific user facility sponsored by the U.S. Department of Energy’s Office of Biological and Environmental Research and located at

  6. The Pill Really Can Be Mightier Than the Sword: A Response to Recent Commentaries

    PubMed Central

    Potts, Malcolm; Graves, Alisha

    2016-01-01

    We appreciate the four commentaries that add new material and fresh perspectives to our article "The pill is mightier than the sword." In emphasizing the role of voluntary family planning and girls’ education as achievable strategies with a potential to make the world a more peaceable place, we did not mean to oversimplify or disregard the intrinsic complexity of human conflict. On the whole, the commentators support and add to our thesis, although we question Pillai and Ya-Chien Wang’s suggestion that we may have overstated the unique human predisposition to kill our own species. We present additional data on male team aggression. PMID:26927598

  7. Edge detection and localization with edge pattern analysis and inflection characterization

    NASA Astrophysics Data System (ADS)

    Jiang, Bo

    2012-05-01

    In general edges are considered to be abrupt changes or discontinuities in two dimensional image signal intensity distributions. The accuracy of front-end edge detection methods in image processing impacts the eventual success of higher level pattern analysis downstream. To generalize edge detectors designed from a simple ideal step function model to real distortions in natural images, research on one dimensional edge pattern analysis to improve the accuracy of edge detection and localization proposes an edge detection algorithm, which is composed by three basic edge patterns, such as ramp, impulse, and step. After mathematical analysis, general rules for edge representation based upon the classification of edge types into three categories-ramp, impulse, and step (RIS) are developed to reduce detection and localization errors, especially reducing "double edge" effect that is one important drawback to the derivative method. But, when applying one dimensional edge pattern in two dimensional image processing, a new issue is naturally raised that the edge detector should correct marking inflections or junctions of edges. Research on human visual perception of objects and information theory pointed out that a pattern lexicon of "inflection micro-patterns" has larger information than a straight line. Also, research on scene perception gave an idea that contours have larger information are more important factor to determine the success of scene categorization. Therefore, inflections or junctions are extremely useful features, whose accurate description and reconstruction are significant in solving correspondence problems in computer vision. Therefore, aside from adoption of edge pattern analysis, inflection or junction characterization is also utilized to extend traditional derivative edge detection algorithm. Experiments were conducted to test my propositions about edge detection and localization accuracy improvements. The results support the idea that these edge

  8. Complete amino acid sequences of three proteinase inhibitors from white sword bean (Canavalia gladiata).

    PubMed

    Park, S S; Sumi, T; Ohba, H; Nakamura, O; Kimura, M

    2000-10-01

    Three major serine proteinase inhibitors (SBI-1, -2, and -3) were purified from the seeds of white sword bean (Canavalia gladiata) by FPLC and reversed-phase HPLC. The sequences of these inhibitors were established by automatic Edman degradation and TOF-mass spectrometry. SBI-1, -2, and -3 consisted of 72, 73, and 75 amino acid residues, with molecular masses of 7806.5, 7919.8, and 8163.4, respectively. The sequences of SBI-1 and -2 coincided with those of CLT I and II [Terada et al. (1994) Biosci. Biotech. Biochem., 58, 376-379] except only N- or C-terminal amino acid residues. Analysis of the amino acid sequences showed that the active sites of the inhibitors contained a Lys21-Ser22 against trypsin and Leu48-Ser49 against chymotrypsin, respectively. Further, it became apparent that about seven disulfide bonds were present. These results suggest that sword bean inhibitors are members of the Bowman-Birk proteinase inhibitor family.

  9. Quality Coaching Counts

    ERIC Educational Resources Information Center

    Gould, Daniel

    2016-01-01

    Scholastic sport is a double-edged sword that can have positive or negative effects. Whether those effects are positive or negative depends on those who wield that sword--chiefly, the school's sports coach. While it is clear that coaches make a difference in ensuring that educational athletics lead to beneficial outcomes for student-athletes, a…

  10. Quality Coaching Counts

    ERIC Educational Resources Information Center

    Gould, Daniel

    2016-01-01

    Scholastic sport is a double-edged sword that can have positive or negative effects. Whether those effects are positive or negative depends on those who wield that sword--chiefly, the school's sports coach. While it is clear that coaches make a difference in ensuring that educational athletics lead to beneficial outcomes for student-athletes, a…

  11. Edge States in Transitional Pipe Flow

    NASA Astrophysics Data System (ADS)

    Schneider, Tobias M.; Eckhardt, Bruno

    2006-11-01

    We study the boundary of the laminar region near the onset of turbulence. Approaching the boundary from the laminar side, the lifetime of perturbations increases, diverges when the boundary is reached, and varies chaotically for larger amplitudes. In the chaotic region, lifetimes vary sensitively with amplitude, consistent with the strange saddle picture of the turbulence proposed earlier. The trajectory on the edge between the laminar and chaotic regions is asymptotic to a single well defined state, essentially independent of the type of perturbation. The edge then becomes the stable manifold of this structure. In the case of a model shear flow, the edge states are simple or period doubled or chaotic trajectories. In the case of pipe flow the edge state seems to remain close to a state with simple vortical structure. Edge of Chaos in a Parallel Shear Flow, Joseph D. Skufca, James A. Yorke, and Bruno Eckhardt, Phys. Rev. Lett. 96, 174101 (2006)

  12. Hippocratic ideal, Faustian bargain and Damocles' sword: erosion of patient autonomy in obstetrics.

    PubMed

    Rybak, E A

    2009-11-01

    Respect for patient autonomy remains a foundational principle guiding the ethical practice of medicine-a mission first articulated by Hippocrates. Damocles, another figure from ancient Greece, provides a useful parable for describing performance under distress: Damocles loses his desire for opulence and power when he notices a sword dangling precariously above his head. Contemporary obstetricians deciding whether to forestall or impose major abdominal surgery on parturients entrusted to their care struggle valiantly in the chasm dividing Hippocratic idealism from the economic realism driven by the medicolegal sword of Damocles. Given the inherent risk of unforeseeable and unsalvageable fetal catastrophe during labor and vaginal delivery, and the often unsubstantiated, yet automatic, allegation of negligence that follows a labor-associated adversity, obstetricians-and their liability insurance carriers-have recalibrated obstetric practice in alignment with the increasingly risk-averse preferences of most patients. Indeed, less intrapartum risk for patients and less corresponding medicolegal exposure for obstetricians help explain the rising cesarean delivery rate and, more importantly, the steady disappearance of higher-risk interventions such as vaginal birth after cesarean (VBAC). Is this increasing reluctance to offer VBAC supervision ethically defensible? This paper argues that it is. Fiduciary professionalism mandates physician self-sacrifice, not self-destruction; a VBAC gone awry without negligence or substandard care may, nevertheless, render future affordable liability coverage unattainable. Yet, the unavailability of VBAC infringes on the autonomy of women who want to assume the intrapartum risks of a VBAC in lieu of a repeat cesarean delivery. The proposed solution is the regionalization of VBAC care provision in designated medical centers and/or the implementation of binding arbitration in an ethical trade-off to enhance patient autonomy regarding the

  13. Randomized SUSAN edge detector

    NASA Astrophysics Data System (ADS)

    Qu, Zhi-Guo; Wang, Ping; Gao, Ying-Hui; Wang, Peng

    2011-11-01

    A speed up technique for the SUSAN edge detector based on random sampling is proposed. Instead of sliding the mask pixel by pixel on an image as the SUSAN edge detector does, the proposed scheme places the mask randomly on pixels to find edges in the image; we hereby name it randomized SUSAN edge detector (R-SUSAN). Specifically, the R-SUSAN edge detector adopts three approaches in the framework of random sampling to accelerate a SUSAN edge detector: procedure integration of response computation and nonmaxima suppression, reduction of unnecessary processing for obvious nonedge pixels, and early termination. Experimental results demonstrate the effectiveness of the proposed method.

  14. James Sowerby: meteorites and his meteoritic sword made for the Emperor of Russia, Alexander I, in 1814

    PubMed Central

    Henderson, Paul

    2013-01-01

    James Sowerby included meteorites in his publications of British and exotic natural history and so raised interest in their nature and origins at a time of much debate and involving the President of the Royal Society, Sir Joseph Banks. The celebrations over the defeat of France in 1814 prompted Sowerby to make a sword from the Cape of Good Hope iron meteorite to present to the Russian Emperor, Alexander I, at the time of his state visit to London in June 1814 and in recognition of his achievements in bringing peace to Europe. The story of its attempted presentation, its final reception and the following response, including publications, all helped to increase interest in meteorites and their properties. The rediscovery of the sword after a lengthy disappearance probably brings an unusual saga to a fitting close.

  15. Examining Acquisition Leaders Readiness to Support Future LandCyber Operations

    DTIC Science & Technology

    2014-04-15

    cyberspace-educated and trained Armed Forces to use advanced technology such as fiber optic, electromagnetic, and laser to pass information. The LandCyber...then vulnerabilities in the cyberspace will overcome the advantage and become a double-edged sword that is self-defeating. Rafferty referred to...support the LandCyber operations. LandCyber operations and advanced technology can be a dream team or a double-edged sword depending on how well the

  16. Nanoindentation near the edge

    Treesearch

    J.E. Jakes; C.R. Frihart; J.F. Beecher; R.J. Moon; P.J. Resto; Z.H. Melgarejo; O.M. Saurez; H. Baumgart; A.A. Elmustafa; D.S. Stone

    2009-01-01

    Whenever a nanoindent is placed near an edge, such as the free edge of the specimen or heterophase interface intersecting the surface, the elastic discontinuity associated with the edge produces artifacts in the load-depth data. Unless properly handled in the data analysis, the artifacts can produce spurious results that obscure any real trends in properties as...

  17. Depth Edge Filtering Using Parameterized Structured Light Imaging

    PubMed Central

    Zheng, Ziqi; Bae, Seho; Yi, Juneho

    2017-01-01

    This research features parameterized depth edge detection using structured light imaging that exploits a single color stripes pattern and an associated binary stripes pattern. By parameterized depth edge detection, we refer to the detection of all depth edges in a given range of distances with depth difference greater or equal to a specific value. While previous research has not properly dealt with shadow regions, which result in double edges, we effectively remove shadow regions using statistical learning through effective identification of color stripes in the structured light images. We also provide a much simpler control of involved parameters. We have compared the depth edge filtering performance of our method with that of the state-of-the-art method and depth edge detection from the Kinect depth map. Experimental results clearly show that our method finds the desired depth edges most correctly while the other methods cannot. PMID:28368350

  18. Depth Edge Filtering Using Parameterized Structured Light Imaging.

    PubMed

    Zheng, Ziqi; Bae, Seho; Yi, Juneho

    2017-04-03

    This research features parameterized depth edge detection using structured light imaging that exploits a single color stripes pattern and an associated binary stripes pattern. By parameterized depth edge detection, we refer to the detection of all depth edges in a given range of distances with depth difference greater or equal to a specific value. While previous research has not properly dealt with shadow regions, which result in double edges, we effectively remove shadow regions using statistical learning through effective identification of color stripes in the structured light images. We also provide a much simpler control of involved parameters. We have compared the depth edge filtering performance of our method with that of the state-of-the-art method and depth edge detection from the Kinect depth map. Experimental results clearly show that our method finds the desired depth edges most correctly while the other methods cannot.

  19. Tasting edge effects

    NASA Astrophysics Data System (ADS)

    Bocquet, Lydéric

    2007-02-01

    We show that the baking of potato wedges constitutes a crunchy example of edge effects, which are usually demonstrated in electrostatics. A simple model of the diffusive transport of water vapor around the potato wedges shows that the water vapor flux diverges at the sharp edges in analogy with its electrostatic counterpart. This increased evaporation at the edges leads to the crispy taste of these parts of the potatoes.

  20. More a plowshare than a sword: the legacy of US Cold War agricultural diplomacy.

    PubMed

    McGlade, Jacqueline

    2009-01-01

    Recently, agriculture has assumed an elevated role in world diplomacy due to pressing issues like international poverty relief, changing environmental conditions, farm trade imbalances, rising food prices, and the diversion of crops into bio-fuel production. Consequently, agricultural interests and production have become increasingly entwined with the politics of national protectionism and identity, domestic security, and the preservation of trading advantage in developed and developing countries alike. This study examines the current impasse in world agricultural negotiations as an outgrowth of US foreign aid and trade policymaking as it evolved during the Cold War. In particular, it chronicles the historic shift in US foreign policy away from "give-away" food aid and surplus sales and toward the championing of global agricultural redevelopment under such programs as the Marshall Plan and PL 480, the Food for Peace program. As more a plowshare than a sword, the American Cold War push for worldwide agricultural modernization led many countries to experience new levels of food self-efficiency and export capabilities. Along with production parity, however, has come escalating levels of trade competition and national protectionism, which challenges again the achievement of world agricultural stability and prosperity.

  1. Leather material found on a 6th B.C. Chinese bronze sword: A technical study

    NASA Astrophysics Data System (ADS)

    Luo, Wugan; Si, Yi; Wang, Hongmin; Qin, Ying; Huang, Fengchun; Wang, Changsui

    2011-09-01

    During July to November, 2006, an important archaeological excavation was conducted in Yun country, Hubei province, southern China. Chinese archaeologists found some remnant of leather materials, covered with red pigments, on a 6th century B.C. Chinese bronze sword. To understand the technology/ies that may have been utilized for manufacturing the leathers, a combined of Raman spectroscopy, FT-IR and XRF was thus applied to the remnant of leather materials. Raman analyses showed that red pigment on the leather was cinnabar (HgS). FT-IR and XRF analyses indicated that the content of some elements, such as Ca (existing as CaCO 3) and Fe (existing as Fe 2O 3), were much higher than those in the surrounding grave soil. The results inferred an application of lime depilation and retting, and the Fe-Al compound salt as tanning agent. And it was furthermore implicated that the Fe-Al salt tanning technique had been developed in the middle and late Spring and Autumn Period of China.

  2. SWORD '99: surveillance of work-related and occupational respiratory disease in the UK.

    PubMed

    Meyer, J D; Holt, D L; Chen, Y; Cherry, N M; McDonald, J C

    2001-05-01

    Systematic reports from chest and occupational physicians under the SWORD and OPRA (Occupational Physicians Reporting Activity) surveillance schemes continue to provide a picture of the incidence of occupational respiratory disease in the UK. An estimated total of 4393 incident cases (comprising 4530 diagnoses) were reported during the 1999 calendar year, an increase of 1427 cases over the previous year. Benign pleural disease was the single most frequently reported condition (28% of all diagnoses reported). Occupational asthma cases (1168; 26%) remained high, as did mesothelioma (1032; 23%). Analysis of trends over the past 8 years shows an increase in mesothelioma cases, but little change in asthma. The annual incidence per 100,000 employed people, 1996-1999, for mesothelioma, lung cancer and pneumoconiosis was high amongst construction workers (28.7), miners and quarrymen (26.5), woodworkers (18.9) and gas, coal and chemical workers (15.2). Trends in mesothelioma incidence by birth cohort continue to show an increase in construction workers and a continuing decline in shipyard and insulation workers. The relative proportion of pneumoconiosis cases attributed to coal mining has fallen steadily in workers born since approximately 1920 and most cases are now in men who have been employed in quarrying and rock drilling.

  3. Leather material found on a 6th B.C. Chinese bronze sword: a technical study.

    PubMed

    Luo, Wugan; Si, Yi; Wang, Hongmin; Qin, Ying; Huang, Fengchun; Wang, Changsui

    2011-09-01

    During July to November, 2006, an important archaeological excavation was conducted in Yun country, Hubei province, southern China. Chinese archaeologists found some remnant of leather materials, covered with red pigments, on a 6th century B.C. Chinese bronze sword. To understand the technology/ies that may have been utilized for manufacturing the leathers, a combined of Raman spectroscopy, FT-IR and XRF was thus applied to the remnant of leather materials. Raman analyses showed that red pigment on the leather was cinnabar (HgS). FT-IR and XRF analyses indicated that the content of some elements, such as Ca (existing as CaCO3) and Fe (existing as Fe2O3), were much higher than those in the surrounding grave soil. The results inferred an application of lime depilation and retting, and the Fe-Al compound salt as tanning agent. And it was furthermore implicated that the Fe-Al salt tanning technique had been developed in the middle and late Spring and Autumn Period of China.

  4. VizieR Online Data Catalog: Stellar groups of Orion's Sword region (Vereshchangin+, 2010)

    NASA Astrophysics Data System (ADS)

    Vereshchangin, S. V.; Chupina, N. V.

    2010-09-01

    The region of Orion's Sword with coordinates RA=83.79°, DE=-5.20° and a size of 1.0°x2.5° is analyzed. We compiled a master catalog of stars observed in the optical, containing positions, proper motions, and UBV photometry for 1634 stars. Using the nearest-neighbor-distance technique, we subdivided the region into stellar groups with different numbers of members. The positions of five groups coincide with known clusters, and two groups coincide with aggregates of stars with Hα emission. We have identified groups with low membership that are moving away from the system. We also considered the kinematic structure of the groups using the AD-diagram method we developed earlier. Most of the stellar clusters and groups display similar kinematics, with the exception of the group OMC-2, which is moving toward its own apex. We also confirmed the existence of the kinematic star group 189 discovered earlier; its position is close to the cluster NGC 1977, and it is probably a component of its corona. (1 data file).

  5. Effects of Hull Scratching, Soaking, and Boiling on Antinutrients in Japanese Red Sword Bean (Canavalia gladiata).

    PubMed

    Une, Satsuki; Nonaka, Koji; Akiyama, Junich

    2016-10-01

    The effects of hull processing, soaking, and boiling on the content or activity of antinutrients in the red sword bean (RSB; Canavalia gladiata) were investigated. RSB seeds were compared with kidney bean (KB; Phaseolus vulgaris) seeds that are starch based and often used as processed products in Japan. RSB seeds had higher weight, thicker hull, and higher protein content, but lower moisture content compared with KB seeds. Because of the strong and thick hull, the relative water absorption of untreated RSB seeds was very low after soaking. Seeds were soaked after dehulling, scratching, and roasting. The results showed that hull scratching was the optimal method for increasing water absorption during soaking compared with dehulling and roasting. After soaking, the water used for soaking was discarded, since it had a high content of polyphenols and bitter taste, and RSB seeds were boiled in fresh water for 20, 40, and 60 min. The results showed that polyphenol and tannin contents, antioxidant activity, and hemagglutinating activity, as well as maltase, sucrase, and trypsin inhibitor activities in scratched RSB seeds decreased significantly after boiling compared with those in raw seeds, whereas amylase inhibitor activity showed no significant change. Overall, it was concluded that the combination of hull scratching, soaking, and boiling in fresh water can reduce thermal-stable or sensitive antinutrients in RSB and thus, significantly improve its nutritional value.

  6. Historical and Metallurgical Characterization of a "Falchion" Sword Manufactured in Caino (Brescia, Italy) in the Early 17th Century A.D.

    NASA Astrophysics Data System (ADS)

    Tonelli, G.; Faccoli, M.; Gotti, R.; Roberti, R.; Cornacchia, G.

    2016-08-01

    A historical and metallurgical characterization of a "falchion" sword manufactured in Caino (Brescia, northern Italy) and dating from the early 17th century was performed to understand the manufacture methods of a Renaissance sword. At first, a set of size measurements was carried out to look for the existence of constant and/or recurring macroscopic sizes, which would indicate a standardized production, or of any type of proportionality between different parts of a sword, which would prove an intentional design activity. Light optical microscopy, scanning electron microscopy, energy-dispersive x-ray spectroscopy, quantometer analyses, and Vickers microhardness tests were then employed to analyze the microstructure and obtain the mechanical properties. All the metallurgical work is supported by an accurate study on the chemical composition of both metal-matrix and nonmetallic inclusions, which allowed for rebuilding and evaluating the efficiency of the whole production process.

  7. Gait alterations can reduce the risk of edge loading.

    PubMed

    Wesseling, Mariska; Meyer, Christophe; De Groote, Friedl; Corten, Kristoff; Simon, Jean-Pierre; Desloovere, Kaat; Jonkers, Ilse

    2016-06-01

    Following metal-on-metal hip arthroplasty, edge loading (i.e., loading near the edge of a prosthesis cup) can increase wear and lead to early revision. The position and coverage angle of the prosthesis cup influence the risk of edge loading. This study investigates the effect of altered gait patterns, more specific hip, and pelvis kinematics, on the orientation of hip contact force and the consequent risk of antero-superior edge loading using muscle driven simulations of gait. With a cup orientation of 25° anteversion and 50° inclination and a coverage angle of 168°, many gait patterns presented risk of edge loading. Specifically at terminal double support, 189 out of 405 gait patterns indicated a risk of edge loading. At this time instant, the high hip contact forces and the proximity of the hip contact force to the edge of the cup indicated the likelihood of the occurrence of edge loading. Although the cup position contributed most to edge loading, altering kinematics considerably influenced the risk of edge loading. Increased hip abduction, resulting in decreasing hip contact force magnitude, and decreased hip extension, resulting in decreased risk on edge loading, are gait strategies that could prevent edge loading. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1069-1076, 2016. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  8. The effects of hive types (shield and sword) on wintering ability, survival rates and strength of honeybee colonies (A. mellifera L.) in spring season.

    PubMed

    Yeninar, Halil; Akyol, Etem; Sahinler, Nuray

    2010-03-01

    This study was carried out to determine the effects of shield and sword comb orientation hive types on wintering ability, survival rates (in winter) and population growth of honeybee colonies (A. mellifera anatoliaca) in spring season. In ancient Anatolia beekeeping; honeybee colonies were identified sword and shield (the colonies which build up the combs vertical and horizontal according to positions of the hive entrance) before the uses of top-opened hive with movable frames. Total twenty honeybee colonies, which have similar condition according to queen age, genotype, number of frames covered with adult worker bees, brood areas and food stocks, were used in this study. Average wintering ability of colonies in the shield and sword groups were found to be 98.57% and 69.76%; average survival rates were found to be 100% and 100% in shield and sword group colonies respectively. The average number of frames covered with adult worker bees at mid June in shield and sword group colonies were found to be 15.6 +/- 1.58, 12.00 +/- 1.25 number/colony and the average brood areas were found as 7863.5 +/- 402.9, 5997.0 +/- 373.3 cm(2)/colony respectively. Differences between the group means on wintering ability, sealed brood areas and colony strength were found significant (P < 0.01), but differences on survival rates were not found significant (P > 0.05). The colonies living in shield (horizontal) hives have showed better wintering ability and more colony population than colonies living in sword (vertical) hives.

  9. Supersonic Leading Edge Receptivity

    NASA Technical Reports Server (NTRS)

    Maslov, Anatoly A.

    1998-01-01

    This paper describes experimental studies of leading edge boundary layer receptivity for imposed stream disturbances. Studies were conducted in the supersonic T-325 facility at ITAM and include data for both sharp and blunt leading edges. The data are in agreement with existing theory and should provide guidance for the development of more complete theories and numerical computations of this phenomena.

  10. The Edge, Fall 1999.

    ERIC Educational Resources Information Center

    Edge, 1999

    1999-01-01

    "The Edge" is a Canadian publication for youth. The mandate of the Edge is to support and celebrate all career journeys embraced by youth. This issue contains career profile articles covering three jobs: crane operator, indoor climbing instructor, and product certification tester. Career trends and the state of today's workplace are also…

  11. Interferometric acquisition and fire control radar for short-range missile defense with optimized radar distribution (SWORD)

    NASA Astrophysics Data System (ADS)

    Smith, Ronald A.; Shipman, Mark; Holder, E. J.; Williams, James K.

    2002-07-01

    The United States Army Space and Missile Defense Command (USASMDC) has interest in a technology demonstration that capitalizes on investment in fire control and smart interceptor technologies that have matured beyond basic research. The concept "SWORD" (Short range missile defense With Optimized Radar Distribution) consists of a novel approach utilizing a missile interceptor and interferometric fire control radar. A hit-to-kill, closed-loop, command guidance scheme is planned that takes advantage of extremely accurate target and interceptor state vectors derived via the fire control radar. The fire control system has the capability to detect, track, and classify multiple threats in a tactical regime as well as simultaneously provide command guidance updates to multiple missile interceptors. The missile interceptor offers a cost reduction potential as well as an enhancement to the kinematics range and lethality over existing SHORAD systems. Additionally, the Radio Frequency (RF) guidance scheme offers increased battlefield weather performance. The Air Defense (AD) community, responding to current threat capabilities and trends, has identified an urgent need to have a capability to counter proliferated, low cost threats with a low cost-per-kill weapon system. The SWORD system will offer a solution that meets this need. The SWORD critical technologies will be identified including a detailed description of each. Validated test results and basic principles of operation will be presented to prove the merit of the past investments. The Deptuy Assistant Secretary of the Army for Research and Technology [DAS(R&T)] has a three-year Science and Technology Program to evaluate the errors and proposed mitigation techniques associated with target spectral dispersion and range gate straddle. Preliminary Bench-Top Experiment results will be presented in this paper.

  12. Escape from extreme specialization: passionflowers, bats and the sword-billed hummingbird.

    PubMed

    Abrahamczyk, S; Souto-Vilarós, D; Renner, S S

    2014-11-22

    A striking example of plant/pollinator trait matching is found between Andean species of Passiflora with 6-14-cm-long nectar tubes and the sword-billed hummingbird, Ensifera ensifera, with up to 11-cm-long bills. Because of the position of their anthers and stigmas, and self-incompatibility, these passionflower species depend on E. ensifera for pollination. Field observations show that the bird and plant distribution match completely and that scarcity of Ensifera results in reduced passionflower seed set. We here use nuclear and plastid DNA sequences to investigate how often and when these mutualisms evolved and under which conditions, if ever, they were lost. The phylogeny includes 26 (70%) of the 37 extremely long-tubed species, 13 (68%) of the 19 species with tubes too short for Ensifera and four of the seven bat-pollinated species for a total of 43 (69%) of all species in Passiflora supersection Tacsonia (plus 11 outgroups). We time-calibrated the phylogeny to infer the speed of any pollinator switching. Results show that Tacsonia is monophyletic and that its stem group dates to 10.7 Ma, matching the divergence at 11.6 Ma of E. ensifera from its short-billed sister species. Whether pollination by short-billed hummingbirds or by Ensifera is the ancestral condition cannot be securely inferred, but extremely long-tubed flowers exclusively pollinated by Ensifera evolved early during the radiation of the Tacsonia clade. There is also evidence of several losses of Ensifera dependence, involving shifts to bat pollination and shorter billed birds. Besides being extremely asymmetric-a single bird species coevolving with a speciose plant clade-the Ensifera/Passiflora system is a prime example of a specialized pollinator not driving plant speciation, but instead being the precondition for the maintenance of isolated populations (through reliable seed set) that then underwent allopatric speciation. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  13. Escape from extreme specialization: passionflowers, bats and the sword-billed hummingbird

    PubMed Central

    Abrahamczyk, S.; Souto-Vilarós, D.; Renner, S. S.

    2014-01-01

    A striking example of plant/pollinator trait matching is found between Andean species of Passiflora with 6–14-cm-long nectar tubes and the sword-billed hummingbird, Ensifera ensifera, with up to 11-cm-long bills. Because of the position of their anthers and stigmas, and self-incompatibility, these passionflower species depend on E. ensifera for pollination. Field observations show that the bird and plant distribution match completely and that scarcity of Ensifera results in reduced passionflower seed set. We here use nuclear and plastid DNA sequences to investigate how often and when these mutualisms evolved and under which conditions, if ever, they were lost. The phylogeny includes 26 (70%) of the 37 extremely long-tubed species, 13 (68%) of the 19 species with tubes too short for Ensifera and four of the seven bat-pollinated species for a total of 43 (69%) of all species in Passiflora supersection Tacsonia (plus 11 outgroups). We time-calibrated the phylogeny to infer the speed of any pollinator switching. Results show that Tacsonia is monophyletic and that its stem group dates to 10.7 Ma, matching the divergence at 11.6 Ma of E. ensifera from its short-billed sister species. Whether pollination by short-billed hummingbirds or by Ensifera is the ancestral condition cannot be securely inferred, but extremely long-tubed flowers exclusively pollinated by Ensifera evolved early during the radiation of the Tacsonia clade. There is also evidence of several losses of Ensifera dependence, involving shifts to bat pollination and shorter billed birds. Besides being extremely asymmetric—a single bird species coevolving with a speciose plant clade—the Ensifera/Passiflora system is a prime example of a specialized pollinator not driving plant speciation, but instead being the precondition for the maintenance of isolated populations (through reliable seed set) that then underwent allopatric speciation. PMID:25274372

  14. The digital step edge

    NASA Technical Reports Server (NTRS)

    Haralick, R. M.

    1982-01-01

    The facet model was used to accomplish step edge detection. The essence of the facet model is that any analysis made on the basis of the pixel values in some neighborhood has its final authoritative interpretation relative to the underlying grey tone intensity surface of which the neighborhood pixel values are observed noisy samples. Pixels which are part of regions have simple grey tone intensity surfaces over their areas. Pixels which have an edge in them have complex grey tone intensity surfaces over their areas. Specially, an edge moves through a pixel only if there is some point in the pixel's area having a zero crossing of the second directional derivative taken in the direction of a non-zero gradient at the pixel's center. To determine whether or not a pixel should be marked as a step edge pixel, its underlying grey tone intensity surface was estimated on the basis of the pixels in its neighborhood.

  15. Multi-indicator Evaluation System for Broadsword, Rod, Sword and Spear Athletes Based on Analytic Hierarchy Process

    NASA Astrophysics Data System (ADS)

    Luo, Lin

    2017-08-01

    In the practical selection of Wushu athletes, the objective evaluation of the level of athletes lacks sufficient technical indicators and often relies on the coach’s subjective judgments. It is difficult to accurately and objectively reflect the overall quality of the athletes without a fully quantified indicator system, thus affecting the level improvement of Wushu competition. The analytic hierarchy process (AHP) is a systemic analysis method combining quantitative and qualitative analysis. This paper realizes structured, hierarchized and quantified decision-making process of evaluating broadsword, rod, sword and spear athletes in the AHP. Combing characteristics of the athletes, analysis is carried out from three aspects, i.e., the athlete’s body shape, physical function and sports quality and 18 specific evaluation indicators established, and then combining expert advice and practical experience, pairwise comparison matrix is determined, and then the weight of the indicators and comprehensive evaluation coefficient are obtained to establish the evaluation model for the athletes, thus providing a scientific theoretical basis for the selection of Wushu athletes. The evaluation model proposed in this paper has realized the evaluation system of broadsword, rod, sword and spear athletes, which has effectively improved the scientific level of Wushu athletes selection in practical application.

  16. Edge wave visualization

    NASA Technical Reports Server (NTRS)

    Dominek, Allen K.; Nguyen, Truong X.

    1991-01-01

    Scattering mechanisms that involve edge waves are addressed. The behavior of edge waves and their interaction with flat, perfectly conducting plates are depicted in the time domain through a visualization of surface currents that flow on the surface, as an incident Gaussian pulse of energy washes over the surface. Viewing these surface currents allows a very clear physical interpretation and appreciation of the scattering process.

  17. Computational insight into the capacitive performance of graphene edge planes

    DOE PAGES

    Zhan, Cheng; Zhang, Yu; Cummings, Peter T.; ...

    2017-02-01

    Recent experiments have shown that electric double-layer capacitors utilizing electrodes consisting of graphene edge plane exhibit higher capacitance than graphene basal plane. However, theoretical understanding of this capacitance enhancement is still limited. Here we applied a self-consistent joint density functional theory calculation on the electrode/electrolyte interface and found that the capacitance of graphene edge plane depends on the edge type: zigzag edge has higher capacitance than armchair edge due to the difference in their electronic structures. We further examined the quantum, dielectric, and electric double-layer (EDL) contributions to the total capacitance of the edge-plane electrodes. Classical molecular dynamics simulation foundmore » that the edge planes have higher EDL capacitance than the basal plane due to better adsorption of counter-ions and higher solvent accessible surface area. Finally, our work therefore has elucidated the capacitive energy storage in graphene edge planes that take into account both the electrode's electronic structure and the EDL structure.« less

  18. The Edge supersonic transport

    NASA Technical Reports Server (NTRS)

    Agosta, Roxana; Bilbija, Dushan; Deutsch, Marc; Gallant, David; Rose, Don; Shreve, Gene; Smario, David; Suffredini, Brian

    1992-01-01

    As intercontinental business and tourism volumes continue their rapid expansion, the need to reduce travel times becomes increasingly acute. The Edge Supersonic Transport Aircraft is designed to meet this demand by the year 2015. With a maximum range of 5750 nm, a payload of 294 passengers and a cruising speed of M = 2.4, The Edge will cut current international flight durations in half, while maintaining competitive first class, business class, and economy class comfort levels. Moreover, this transport will render a minimal impact upon the environment, and will meet all Federal Aviation Administration Part 36, Stage III noise requirements. The cornerstone of The Edge's superior flight performance is its aerodynamically efficient, dual-configuration design incorporating variable-geometry wingtips. This arrangement combines the benefits of a high aspect ratio wing at takeoff and low cruising speeds with the high performance of an arrow-wing in supersonic cruise. And while the structural weight concerns relating to swinging wingtips are substantial, The Edge looks to ever-advancing material technologies to further increase its viability. Heeding well the lessons of the past, The Edge design holds economic feasibility as its primary focus. Therefore, in addition to its inherently superior aerodynamic performance, The Edge uses a lightweight, largely windowless configuration, relying on a synthetic vision system for outside viewing by both pilot and passengers. Additionally, a fly-by-light flight control system is incorporated to address aircraft supersonic cruise instability. The Edge will be produced at an estimated volume of 400 aircraft and will be offered to airlines in 2015 at $167 million per transport (1992 dollars).

  19. Hierarchy in a double braneworld

    SciTech Connect

    Guerrero, Rommel; Rodriguez, R. Omar; Melfo, Alejandra; Pantoja, Nelson

    2006-10-15

    We show that the hierarchy between the Planck and the weak scales can follow from the tendency of gravitons and fermions to localize at different edges of a thick double wall embedded in an AdS{sub 5} spacetime without reflection symmetry. This double wall is a stable BPS thick-wall solution with two subwalls located at its edges; fermions are coupled to the scalar field through Yukawa interactions, but the lack of reflection symmetry forces them to be localized in one of the subwalls. We show that the graviton zero-mode wave function is suppressed in the fermion edge by an exponential function of the distance between the subwalls, and that the massive modes decouple so that Newtonian gravity is recuperated.

  20. Adaptable edge quality metric

    NASA Astrophysics Data System (ADS)

    Strickland, Robin N.; Chang, Dunkai K.

    1990-09-01

    A new quality metric for evaluating edges detected by digital image processing algorithms is presented. The metric is a weighted sum of measures of edge continuity smoothness thinness localization detection and noisiness. Through a training process we can design weights which optimize the metric for different users and applications. We have used the metric to compare the results of ten edge detectors when applied to edges degraded by varying degrees of blur and varying degrees and types of noise. As expected the more optimum Difference-of-Gaussians (DOG) and Haralick methods outperform the simpler gradient detectors. At high signal-to-noise (SNR) ratios Haralick''s method is the best choice although it exhibits a sudden drop in performance at lower SNRs. The DOG filter''s performance degrades almost linearly with SNR and maintains a reasonably high level at lower SNRs. The same relative performances are observed as blur is varied. For most of the detectors tested performance drops with increasing noise correlation. Noise correlated in the same direction as the edge is the most destructive of the noise types tested.

  1. High Speed Edge Detection

    NASA Technical Reports Server (NTRS)

    Prokop, Norman F (Inventor)

    2015-01-01

    Analog circuits for detecting edges in pixel arrays are disclosed. A comparator may be configured to receive an all pass signal and a low pass signal for a pixel intensity in an array of pixels. A latch may be configured to receive a counter signal and a latching signal from the comparator. The comparator may be configured to send the latching signal to the latch when the all pass signal is below the low pass signal minus an offset. The latch may be configured to hold a last negative edge location when the latching signal is received from the comparator.

  2. High Speed Edge Detection

    NASA Technical Reports Server (NTRS)

    Prokop, Norman F (Inventor)

    2016-01-01

    Analog circuits for detecting edges in pixel arrays are disclosed. A comparator may be configured to receive an all pass signal and a low pass signal for a pixel intensity in an array of pixels. A latch may be configured to receive a counter signal and a latching signal from the comparator. The comparator may be configured to send the latching signal to the latch when the all pass signal is below the low pass signal minus an offset. The latch may be configured to hold a last negative edge location when the latching signal is received from the comparator.

  3. The Inner Urban Edge

    ERIC Educational Resources Information Center

    Ferebee, Ann; Carpenter, Edward K.

    1974-01-01

    In this article, renewal of the inner urban edge is discussed. Norfolk (Virginia) is attempting to blur the difference between old and new neighbor hoods through zoning and architectural controls. Cincinnati (Ohio) is developing an environmentally sound hillside design. Reading (Pennsylvania) is utilizing old railyards for greenbelts of hiking and…

  4. Edge Detection in Landing Budgerigars (Melopsittacus undulatus)

    PubMed Central

    Bhagavatula, Partha; Claudianos, Charles; Ibbotson, Michael; Srinivasan, Mandyam

    2009-01-01

    Background While considerable scientific effort has been devoted to studying how birds navigate over long distances, relatively little is known about how targets are detected, obstacles are avoided and smooth landings are orchestrated. Here we examine how visual features in the environment, such as contrasting edges, determine where a bird will land. Methodology/Principal Findings Landing in budgerigars (Melopsittacus undulatus) was investigated by training them to fly from a perch to a feeder, and video-filming their landings. The feeder was placed on a grey disc that produced a contrasting edge against a uniformly blue background. We found that the birds tended to land primarily at the edge of the disc and walk to the feeder, even though the feeder was in the middle of the disc. This suggests that the birds were using the visual contrast at the boundary of the disc to target their landings. When the grey level of the disc was varied systematically, whilst keeping the blue background constant, there was one intermediate grey level at which the budgerigar's preference for the disc boundary disappeared. The budgerigars then landed randomly all over the test surface. Even though this disc is (for humans) clearly distinguishable from the blue background, it offers very little contrast against the background, in the red and green regions of the spectrum. Conclusions We conclude that budgerigars use visual edges to target and guide landings. Calculations of photoreceptor excitation reveal that edge detection in landing budgerigars is performed by a color-blind luminance channel that sums the signals from the red and green photoreceptors, or, alternatively, receives input from the red double-cones. This finding has close parallels to vision in honeybees and primates, where edge detection and motion perception are also largely color-blind. PMID:19809500

  5. Far infrared edge photoresponse and persistent edge transport in an inverted InAs/GaSb heterostructure

    SciTech Connect

    Dyer, G. C.; Olson, B. V.; Hawkins, S. D.; Klem, J. F.; Shaner, E. A.; Pan, W.; Shi, X.

    2016-01-04

    Direct current (DC) transport and far infrared photoresponse were studied an InAs/GaSb double quantum well with an inverted band structure. The DC transport depends systematically upon the DC bias configuration and operating temperature. Surprisingly, it reveals robust edge conduction despite prevalent bulk transport in our device of macroscopic size. Under 180 GHz far infrared illumination at oblique incidence, we measured a strong photovoltaic response. We conclude that quantum spin Hall edge transport produces the observed transverse photovoltages. Overall, our experimental results support a hypothesis that the photoresponse arises from direct coupling of the incident radiation field to edge states.

  6. Resolving the chemical structures of off-odorants and potentially harmful substances in toys-example of children's swords.

    PubMed

    Denk, Philipp; Velasco-Schön, Cristina; Buettner, Andrea

    2017-07-11

    Most children's toys on the market are primarily made out of plastic and other complex composite materials. Consumer complaints about offensive odors or irritating effects associated with toy products have increased in recent years. One example is the strongly perceivable negative odor reported for a particular series of toy swords. Characterizing the presence of contaminants, including those that have the potential to be deleterious to health, in such products is a significant analytical challenge due to the high baseline abundance of chemical constituents of the materials used in the products. In the present study, the nature of offensive odorants associated with toy sword products was examined by gas chromatography (GC). After initial sensory evaluations, the volatile compounds from the toy products were recovered using solvent extraction and solvent-assisted flavor evaporation. The extracts were analyzed using GC-olfactometry (GC-O) and two-dimensional GC-O coupled with mass spectrometry (GC-GC-MS/O). A total of 26 odor-active compounds, including aromatic hydrocarbons and phenols, were identified among numerous non-odorous volatile by-products. These substances also included polycyclic aromatic hydrocarbons, which were analyzed by GC-MS. Representative substances were naphthalene and 1,2-dihydronaphthalene that exhibited moldy, mothball-like odor impressions, and phenol derivatives with leather-like, phenolic, horse-stable-like smells. The odorants detected correlated with the assigned attributes from the sensory analyses. This study clearly shows that the detection and identification of such odorous contaminants can provide key indications of potentially harmful yet unknown substances in everyday products such as toys. Graphical abstract ᅟ.

  7. Superpixel edges for boundary detection

    SciTech Connect

    Moya, Mary M.; Koch, Mark W.

    2016-07-12

    Various embodiments presented herein relate to identifying one or more edges in a synthetic aperture radar (SAR) image comprising a plurality of superpixels. Superpixels sharing an edge (or boundary) can be identified and one or more properties of the shared superpixels can be compared to determine whether the superpixels form the same or two different features. Where the superpixels form the same feature the edge is identified as an internal edge. Where the superpixels form two different features, the edge is identified as an external edge. Based upon classification of the superpixels, the external edge can be further determined to form part of a roof, wall, etc. The superpixels can be formed from a speckle-reduced SAR image product formed from a registered stack of SAR images, which is further segmented into a plurality of superpixels. The edge identification process is applied to the SAR image comprising the superpixels and edges.

  8. Shape of patch edges affects edge permeability for meadow voles.

    PubMed

    Nams, Vilis O

    2012-09-01

    Human development typically fragments natural habitats into patches, affecting population and metapopulation dynamics via changes in animal behavior. Emigration from one habitat patch to another has a large effect on population and metapopulation dynamics. One factor that affects emigration is permeability of patch edges. This study looks at the effects of edge shape (convex, concave, and straight) on edge permeability for meadow voles (Microtus pennsylvanicus).. I tested five hypotheses for responses of animal movement to patch shape: (1) neutral edge response; (2) edge attraction; (3) edge avoidance; (4) time-minimizing, in which an animal attempts to minimize the time spent in inhospitable matrix, and thus travels as far as possible in the patch before crossing the edge; and (5) protection, in which an animal attempts to maximize protection while in the inhospitable matrix by keeping the patch close by. These hypotheses were tested by an experimental manipulation of meadow vole habitats. A strip was mowed with different edge shapes through an old field, and vole response was measured by tracking plates. Voles crossed edges at concave treatments twice as often compared to convex and straight shapes. Hypotheses (2) and (5) were supported. Although edge attraction causes a passive effect of a decrease in edge-crossing at concavities, this effect was eclipsed by the active effect of voles choosing to cross at concavities. The results can be generalized to edge tortuosity in general. Conservation biologists should consider edge shapes when exploring the effects of habitat fragmentation on animal populations.

  9. Commentary: Hyperbaric oxygen treatment for wounds - evidence and the Sword of Damocles.

    PubMed

    Laden, Gerard

    2015-12-01

    Increased access to any treatment sensibly follows the clinical and cost benefit being established. For many treatments this requires multiple, high-quality clinical trials and supporting cost analysis. Cost analysis may be applied to a single treatment or used to compare two or more treatments. Clinical efficacy and cost benefit are best scrutinised and validated by publication in the peer-reviewed literature. True peer review is most effectively achieved 'after publication' by the wider scientific community, i.e., the journal readers. However, initially an editor, usually advised by referees, is asked to make a judgment on a paper's suitability for publication. It follows that medical journals are in a position of power and responsibility. Researchers and editors know publications are currency; effectively they are the equivalent of academic bitcoins. Regarding the paper in this issue by Santema et al., the same authors, in designing a prospective randomised controlled trial (RCT) of the role of hyperbaric oxygen treatment (HBOT) in diabetic wounds, included the name "Damocles" in that trial's title. Readers will perhaps appreciate from my comments below as a referee for the Santema et al. paper, that behind the scenes "the Sword of Damocles" (an allusion to the imminent and ever-present peril faced by those in positions of power) hangs over researchers, treating physician, journal editors and referees alike. Whilst positive about its content, upon reflection, my concern was the anticipated reception of this paper by the journal readership. This is, of course, a matter for the Editor; however, herewith is my reasoning. Further to the body of published work by Bennett et al., and others that has focused attention on the lack of good quality evidence for the use of HBOT for most indications, I think this regrettable state of affairs is now both known and accepted by mainstream healthcare purchasers and providers. I speculate that all these bodies already

  10. Edge detection by nonlinear dynamics

    SciTech Connect

    Wong, Yiu-fai

    1994-07-01

    We demonstrate how the formulation of a nonlinear scale-space filter can be used for edge detection and junction analysis. By casting edge-preserving filtering in terms of maximizing information content subject to an average cost function, the computed cost at each pixel location becomes a local measure of edgeness. This computation depends on a single scale parameter and the given image data. Unlike previous approaches which require careful tuning of the filter kernels for various types of edges, our scheme is general enough to be able to handle different edges, such as lines, step-edges, corners and junctions. Anisotropy in the data is handled automatically by the nonlinear dynamics.

  11. Exclusive contracts in the hospital setting: a two-edged sword: part 2: pros and cons, avoidance strategies, and negotiating tips.

    PubMed

    Portman, Robert M

    2007-06-01

    Hospitals routinely enter into contracts with radiology groups for the right to be the exclusive providers of radiologic services at the facilities in exchange for the groups' agreeing to provide and manage all aspects of those services within the hospitals. These exclusive contracts generally result in radiology departments and associated equipment being closed off to physicians who are not part of the contracting groups. Although exclusive contracts offer obvious benefits to the physicians who receive them and obvious disadvantages for those who are excluded, they also present pitfalls for physicians in the chosen group. Part 1 of this article discussed the legal issues raised by exclusive contracts. Part 2 weighs the practical advantages and disadvantages of exclusive contracts for physicians covered and not covered by such contracts and strategies for avoiding them, as well as provisions that can be included in medical staff bylaws to protect physicians from the automatic termination of privileges when a hospital enters into or terminates an exclusive contract. The remainder of the article provides tips on specific provisions of exclusive contracts that should be included or avoided.

  12. Playing Along the Edge

    NASA Image and Video Library

    2016-08-13

    Strands and arches of plasma streamed above the edge of the Sun for over a day, pulled by powerful magnetic forces (Aug. 11-12, 2016). The tug and pull of material heated to about 60,000 degrees C. was viewed in extreme ultraviolet light. This kind of dynamic flow of materials is rather common, though this grouping was larger than most. http://photojournal.jpl.nasa.gov/catalog/PIA17913

  13. Edge turbulence in tokamaks

    NASA Astrophysics Data System (ADS)

    Nedospasov, A. V.

    1992-12-01

    Edge turbulence is of decisive importance for the distribution of particle and energy fluxes to the walls of tokamaks. Despite the availability of extensive experimental data on the turbulence properties, its nature still remains a subject for discussion. This paper contains a review of the most recent theoretical and experimental studies in the field, including mainly the studies to which Wootton (A.J. Wooton, J. Nucl. Mater. 176 & 177 (1990) 77) referred to most in his review at PSI-9 and those published later. The available theoretical models of edge turbulence with volume dissipation due to collisions fail to fully interpret the entire combination of experimental facts. In the scrape-off layer of a tokamak the dissipation prevails due to the flow of current through potential shifts near the surface of limiters of divertor plates. The different origins of turbulence at the edge and in the core plasma due to such dissipation are discussed in this paper. Recent data on the electron temperature fluctuations enabled one to evaluate the electric probe measurements of turbulent flows of particles and heat critically. The latest data on the suppression of turbulence in the case of L-H transitions are given. In doing so, the possibility of exciting current instabilities in biasing experiments (rather than only to the suppression of existing turbulence) is given some attention. Possible objectives of further studies are also discussed.

  14. Edge transport in InAs and InAs/GaSb quantum wells

    NASA Astrophysics Data System (ADS)

    Mueller, Susanne; Mittag, Christopher; Tschirky, Thomas; Charpentier, Christophe; Wegscheider, Werner; Ensslin, Klaus; Ihn, Thomas

    2017-08-01

    We investigate low-temperature transport through single InAs quantum wells and broken-gap InAs/GaSb double quantum wells. Nonlocal measurements in the regime beyond bulk pinch-off confirm the presence of edge conduction in InAs quantum wells. The edge resistivity of 1 -2 k Ω /μ m is of the same order of magnitude as edge resistivities measured in the InAs/GaSb double quantum well system. Measurements in a tilted magnetic field suggests an anisotropy of the conducting regions at the edges with a larger extent in the plane of the sample than normal to it. Finger-gate samples on both material systems shine light on the length dependence of the edge resistance with the intent to unravel the nature of edge conduction in InAs/GaSb coupled quantum wells.

  15. Bulgaria: The Double Edge of Economy and Demography

    ERIC Educational Resources Information Center

    Georgieva, Patricia

    2004-01-01

    The higher education and research sector in Bulgaria is undergoing a gradual change. Whether this transformation will bring success or failure depends on how prepared stakeholders are to meet associated challenges and opportunities. The mobility of academics and the related phenomenon of brain drain need careful investigation. Academic teachers…

  16. Along Freedom's Double Edge: The Arab Press Under Israeli Occupation.

    ERIC Educational Resources Information Center

    Nasser, Munir K.

    This paper examines the Arab press under Israeli occupation and presents two hypotheses: freedom of the press under occupation serves both Israeli interests and the Arab population, and freedom of the Arab press under occupation is "relative" and "controlled." By allowing freedom of expression, the Israelis achieve several…

  17. Competing edge networks

    NASA Astrophysics Data System (ADS)

    Parsons, Mark; Grindrod, Peter

    2012-06-01

    We introduce a model for a pair of nonlinear evolving networks, defined over a common set of vertices, subject to edgewise competition. Each network may grow new edges spontaneously or through triad closure. Both networks inhibit the other's growth and encourage the other's demise. These nonlinear stochastic competition equations yield to a mean field analysis resulting in a nonlinear deterministic system. There may be multiple equilibria; and bifurcations of different types are shown to occur within a reduced parameter space. This situation models competitive communication networks such as BlackBerry Messenger displacing SMS; or instant messaging displacing emails.

  18. Double Photobomb

    NASA Image and Video Library

    2015-09-14

    NASA’s Solar Dynamics Observatory captured this image of Earth and the moon transiting the sun together on Sept. 13, 2015. The edge of Earth, visible near the top of the frame, appears fuzzy because Earth’s atmosphere blocks different amounts of light at different altitudes. On the left, the moon’s edge is perfectly crisp, because it has no atmosphere. This image was taken in extreme ultraviolet wavelengths of 171 angstroms. Though this light is invisible to our eyes, it is typically colorized in gold. Credits: NASA/SDO

  19. Edge of chaos in the transition to turbulence

    NASA Astrophysics Data System (ADS)

    Eckhardt, Bruno

    2006-03-01

    We study the boundary of the laminar region near the onset of turbulence. Approaching the boundary from the laminar side, the lifetime of perturbations increases, diverges when the boundary is reached, and varies chaotically for larger amplitudes. In the chaotic region, lifetimes vary sensitively with amplitude, consistent with the strange saddle picture of the turbulence proposed earlier. The trajectory on the edge between the laminar and chaotic regions is asymptotic to a single well defined state, essentially independent of the type of perturbation. The edge then becomes the stable manifold of this structure. In the case of a model shear flow, the edge states are simple or period doubled or chaotic trajectories. The case of pipe flow shows less variability and the edge state seems to remain close to a state with simple vortical structure. This is joint work with T.M. Schneider (U Marburg), J.D. Skufca (Clarkson U) and J. Yorke (U Maryland).

  20. Gapped symmetric edges of symmetry-protected topological phases

    NASA Astrophysics Data System (ADS)

    Lu, Yuan-Ming; Lee, Dung-Hai

    2014-05-01

    Symmetry-protected topological (SPT) phases are gapped quantum phases which host symmetry-protected gapless edge excitations. On the other hand, the edge states can be gapped by spontaneously breaking symmetry. We show that topological defects on the symmetry-broken edge cannot proliferate due to their fractional statistics. A gapped symmetric boundary, however, can be achieved between an SPT phase and certain fractionalized phases by condensing the bound state of a topological defect and an anyon. We demonstrate this by two examples in two dimensions: an exactly solvable model for the boundary between a topological Ising paramagnet and the double-semion model, and a fermionic example about the quantum spin Hall edge. Such a hybrid structure containing both SPT phase and fractionalized phase generally support ground-state degeneracy on a torus.

  1. Double helicenes

    NASA Astrophysics Data System (ADS)

    Bachrach, Steven M.

    2016-12-01

    The even double helicenes with 4-12 phenyl groups in each helix were examined at B3LYP-D3/6-311G(d). The double helicenes with 4-10 phenyl rings are less than twice as strained as their component helicenes; the strain results from twisting about the shared naphthyl moiety, with accompanying loss of aromaticity. These compounds should be reasonable synthetic targets, and computed NMR shifts are provided to aid in their characterization.

  2. Are shrubland birds edge specialists?

    PubMed

    Schlossberg, Scott; King, David I

    2008-09-01

    In studies of forest fragmentation, birds of scrubby, early-successional habitats are considered edge specialists. Because these birds are assumed to thrive in fragmented, edge-dominated areas, their landscape ecology has received little attention from ecologists. With populations of shrubland birds declining throughout the eastern United States, the question of whether or not these birds really prefer edge habitats has important conservation implications. We used a meta-analysis to test how edges affect the abundance of shrubland birds in early-successional habitats. We analyzed data for 17 species from seven studies that compared the abundances of birds in the interiors and edges of regenerating clearcuts surrounded by mature forest. The meta-analysis clearly showed that shrubland birds avoid edges. All 17 species tested had higher abundances in patch centers than along edges, and edge effects were significant for 8 of 17 species. The key implication of this result is that small or irregular patches, dominated by edge, are unlikely to provide suitable habitat for shrubland birds. Thus, management for these declining species should involve providing large patches and minimizing edges. These findings demonstrate the importance of testing widely accepted ecological classifications and the need to view landscape ecology from the perspective of non-forest wildlife.

  3. Edge remap for solids

    SciTech Connect

    Kamm, James R.; Love, Edward; Robinson, Allen C.; Young, Joseph G.; Ridzal, Denis

    2013-12-01

    We review the edge element formulation for describing the kinematics of hyperelastic solids. This approach is used to frame the problem of remapping the inverse deformation gradient for Arbitrary Lagrangian-Eulerian (ALE) simulations of solid dynamics. For hyperelastic materials, the stress state is completely determined by the deformation gradient, so remapping this quantity effectively updates the stress state of the material. A method, inspired by the constrained transport remap in electromagnetics, is reviewed, according to which the zero-curl constraint on the inverse deformation gradient is implicitly satisfied. Open issues related to the accuracy of this approach are identified. An optimization-based approach is implemented to enforce positivity of the determinant of the deformation gradient. The efficacy of this approach is illustrated with numerical examples.

  4. On the Edge

    NASA Image and Video Library

    2015-02-04

    In today's image, Mercury's horizon cuts a striking edge against the stark blackness of space. On the right, sunlight harshly brings the landscape into relief while on the left, the surface is shrouded in the darkness of night. This image was acquired as part of MDIS's limb imaging campaign. Once per week, MDIS captures images of Mercury's limb, with an emphasis on imaging the southern hemisphere limb. These limb images provide information about Mercury's shape and complement measurements of topography made by the Mercury Laser Altimeter (MLA) of Mercury's northern hemisphere. Date acquired: January 20, 2015 Image Mission Elapsed Time (MET): 64084239 Image ID: 7831084 Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS) WAC filter: 7 (748 nanometers) Center Latitude: -54.45° Center Longitude: 90.52° E Center Resolution: 401 meters/pixel http://photojournal.jpl.nasa.gov/catalog/PIA19192

  5. Edge phonons in black phosphorus

    PubMed Central

    Ribeiro, H. B.; Villegas, C. E. P.; Bahamon, D. A.; Muraca, D.; Castro Neto, A. H.; de Souza, E. A. T.; Rocha, A. R.; Pimenta, M. A.; de Matos, C. J. S.

    2016-01-01

    Black phosphorus has recently emerged as a new layered crystal that, due to its peculiar and anisotropic crystalline and electronic band structures, may have important applications in electronics, optoelectronics and photonics. Despite the fact that the edges of layered crystals host a range of singular properties whose characterization and exploitation are of utmost importance for device development, the edges of black phosphorus remain poorly characterized. In this work, the atomic structure and behaviour of phonons near different black phosphorus edges are experimentally and theoretically studied using Raman spectroscopy and density functional theory calculations. Polarized Raman results show the appearance of new modes at the edges of the sample, and their spectra depend on the atomic structure of the edges (zigzag or armchair). Theoretical simulations confirm that the new modes are due to edge phonon states that are forbidden in the bulk, and originated from the lattice termination rearrangements. PMID:27412813

  6. Edge phonons in black phosphorus

    NASA Astrophysics Data System (ADS)

    Ribeiro, H. B.; Villegas, C. E. P.; Bahamon, D. A.; Muraca, D.; Castro Neto, A. H.; de Souza, E. A. T.; Rocha, A. R.; Pimenta, M. A.; de Matos, C. J. S.

    2016-07-01

    Black phosphorus has recently emerged as a new layered crystal that, due to its peculiar and anisotropic crystalline and electronic band structures, may have important applications in electronics, optoelectronics and photonics. Despite the fact that the edges of layered crystals host a range of singular properties whose characterization and exploitation are of utmost importance for device development, the edges of black phosphorus remain poorly characterized. In this work, the atomic structure and behaviour of phonons near different black phosphorus edges are experimentally and theoretically studied using Raman spectroscopy and density functional theory calculations. Polarized Raman results show the appearance of new modes at the edges of the sample, and their spectra depend on the atomic structure of the edges (zigzag or armchair). Theoretical simulations confirm that the new modes are due to edge phonon states that are forbidden in the bulk, and originated from the lattice termination rearrangements.

  7. [Double responses].

    PubMed

    Motté, G; Dinanian, S; Sebag, C; Drieu, L; Slama, M

    1995-12-01

    Double response is a rare electrocardiographic phenomenon requiring two atrioventricular conduction pathways with very different electrophysiological properties. Double ventricular responses are the usual manifestation: an atrial depolarisation (spontaneous or provoked, anticipated or not) is followed by a first ventricular response dependent on an accessory pathway or a rapid nodal pathway and then a second response resulting from sufficiently delayed transmission through a nodal pathway for the ventricles to have recovered their excitability when the second wave of activation reaches them. A simple curiosity when isolated and occurring under unusual conditions, particularly during electrophysiological investigation of the Wolff-Parkinson-White syndrome, the double response may initiate symptomatic non-reentrant junctional tachycardia when associated with nodal duality and repeating from atria in sinus rhythm. The functional incapacity and resistance to antiarrhythmic therapy may require referral for ablation of the slow pathway.

  8. The Facilitator's Edge: Group Sessions for Edge-ucators.

    ERIC Educational Resources Information Center

    Handcock, Helen

    The Facilitator's Edge is a workshop series based on the life/work messages of The Edge magazine. The workshops are deigned to help educators, youth workers, and their career practitioners facilitate conscious career building. This manual consists of five group sessions, each focusing on a different career-building theme. "Megatrends and…

  9. The Facilitator's Edge: Group Sessions for Edge-ucators.

    ERIC Educational Resources Information Center

    Handcock, Helen

    The Facilitator's Edge is a workshop series based on the life/work messages of The Edge magazine. The workshops are deigned to help educators, youth workers, and their career practitioners facilitate conscious career building. This manual consists of five group sessions, each focusing on a different career-building theme. "Megatrends and…

  10. Edge-edge interactions in stacked graphene nanoplatelets

    SciTech Connect

    Cruz Silva, Eduardo; Terrones Maldonado, Humberto; Terrones Maldonado, Mauricio; Jia, Xiaoting; Sumpter, Bobby G; Dresselhaus, M; Meunier, V.

    2013-01-01

    High-resolution transmission electron microscopy (HRTEM) studies show the dynamics of small graphene platelets on larger graphene layers. The platelets move nearly freely to eventually lock in at well-defined positions close to the edges of the larger underlying graphene sheet. While such movement is driven by a shallow potential energy surface described by an interplane interaction, the lock-in position occurs by via edge-edge interactions of the platelet and the graphene surface located underneath. Here we quantitatively study this behavior using van der Waals density functional calculations. Local interactions at the open edges are found to dictate stacking configurations that are different from Bernal (AB) stacking. These stacking configurations are known to be otherwise absent in edge-free two-dimensional (2D) graphene. The results explain the experimentally observed platelet dynamics and provide a detailed account of the new electronic properties of these combined systems.

  11. Giant edge state splitting at atomically precise graphene zigzag edges

    PubMed Central

    Wang, Shiyong; Talirz, Leopold; Pignedoli, Carlo A.; Feng, Xinliang; Müllen, Klaus; Fasel, Roman; Ruffieux, Pascal

    2016-01-01

    Zigzag edges of graphene nanostructures host localized electronic states that are predicted to be spin-polarized. However, these edge states are highly susceptible to edge roughness and interaction with a supporting substrate, complicating the study of their intrinsic electronic and magnetic structure. Here, we focus on atomically precise graphene nanoribbons whose two short zigzag edges host exactly one localized electron each. Using the tip of a scanning tunnelling microscope, the graphene nanoribbons are transferred from the metallic growth substrate onto insulating islands of NaCl in order to decouple their electronic structure from the metal. The absence of charge transfer and hybridization with the substrate is confirmed by scanning tunnelling spectroscopy, which reveals a pair of occupied/unoccupied edge states. Their large energy splitting of 1.9 eV is in accordance with ab initio many-body perturbation theory calculations and reflects the dominant role of electron–electron interactions in these localized states. PMID:27181701

  12. The Edge of Jupiter

    NASA Image and Video Library

    2017-04-19

    This enhanced color Jupiter image, taken by the JunoCam imager on NASA's Juno spacecraft, showcases several interesting features on the apparent edge (limb) of the planet. Prior to Juno's fifth flyby over Jupiter's mysterious cloud tops, members of the public voted on which targets JunoCam should image. This picture captures not only a fascinating variety of textures in Jupiter's atmosphere, it also features three specific points of interest: "String of Pearls," "Between the Pearls," and "An Interesting Band Point." Also visible is what's known as the STB Spectre, a feature in Jupiter's South Temperate Belt where multiple atmospheric conditions appear to collide. JunoCam images of Jupiter sometimes appear to have an odd shape. This is because the Juno spacecraft is so close to Jupiter that it cannot capture the entire illuminated area in one image -- the sides get cut off. Juno acquired this image on March 27, 2017, at 2:12 a.m. PDT (5:12 a.m. EDT), as the spacecraft performed a close flyby of Jupiter. When the image was taken, the spacecraft was about 12,400 miles (20,000 kilometers) from the planet. This enhanced color image was created by citizen scientist Bjorn Jonsson. https://photojournal.jpl.nasa.gov/catalog/PIA21389

  13. Widely tunable edge emitters

    NASA Astrophysics Data System (ADS)

    Sarlet, Gert; Wesstrom, Jan-Olof; Rigole, Pierre-Jean; Broberg, Bjoern

    2001-11-01

    We will present the current state-of-the-art in widely tunable edge emitting lasers for WDM applications. Typical applications for a tunable laser will be discussed, and the different types of tunable lasers available today will be compared with respect to the requirements posed by these applications. We will focus on the DBR-type tunable lasers - DBR, SG-DBR and GCSR - which at present seem to be the only tunable lasers mature enough for real-life applications. Their main advantages are that they are all monolithic, with no moving parts, and can be switched from one frequency to the other very rapidly since the tuning is based on carrier injection and not on thermal or mechanical changes. We will briefly discuss the working principle of each of these devices, and present typical performance characteristics. From a manufacturing point of view, rapid characterization of the lasers is crucial; therefore an overview will be given of different characterization schemes that have recently been proposed. For the end user, reliability is the prime issue. We will show results of degradation studies on these lasers and outline how the control electronics that drive the laser can compensate for any frequency drift. Finally, we will also discuss the impact of the requirement for rapid frequency switching on the design of the control electronics.

  14. Double Crater

    NASA Image and Video Library

    2012-03-23

    A double crater, called a crater doublet, is seen in the bottom right part of this image from NASA Dawn spacecraft of asteroid Vesta. This crater doublet was likely formed by the simultaneous impact of two fragments of a split projectile.

  15. Wing Leading Edge Debris Analysis

    NASA Technical Reports Server (NTRS)

    Shah, Sandeep; Jerman, Gregory

    2004-01-01

    This is a slide presentation showing the Left Wing Leading Edge (WLE) heat damage observations: Heavy "slag" deposits on select RCC panels. Eroded and knife-edged RCC rib sections. Excessive overheating and slumping of carrier panel tiles. Missing or molten attachment bolts but intact bushing. Deposit mainly on "inside" RCC panel. Deposit on some fractured RCC surface

  16. Rock Segmentation through Edge Regrouping

    NASA Technical Reports Server (NTRS)

    Burl, Michael

    2008-01-01

    Rockster is an algorithm that automatically identifies the locations and boundaries of rocks imaged by the rover hazard cameras (hazcams), navigation cameras (navcams), or panoramic cameras (pancams). The software uses edge detection and edge regrouping to identify closed contours that separate the rocks from the background.

  17. Improved Edge Performance in MRF

    NASA Technical Reports Server (NTRS)

    Shorey, Aric; Jones, Andrew; Durnas, Paul; Tricard, Marc

    2004-01-01

    The fabrication of large segmented optics requires a polishing process that can correct the figure of a surface to within a short distance from its edges-typically, a few millimeters. The work here is to develop QED's Magnetorheological Finishing (MRF) precision polishing process to minimize residual edge effects.

  18. Singular behavior at the edge of Laughlin states

    NASA Astrophysics Data System (ADS)

    Can, T.; Forrester, P. J.; Téllez, G.; Wiegmann, P.

    2014-06-01

    A distinguishing feature of fractional quantum Hall (FQH) states is a singular behavior of equilibrium densities at boundaries. In contrast to states at integer filling fraction, such quantum liquids posses an additional dipole moment localized near edges. It enters observable quantities such as universal dispersion of edge states and Lorentz shear stress. For a Laughlin state, this behavior is seen as a peak, or overshoot, in the single-particle density near the edge, reflecting a general tendency of electrons in FQH states to cluster near edges. We compute the singular edge behavior of the one-particle density by a perturbative expansion carried out around a completely filled Landau level. This correction is shown to fully capture the dipole moment and the major features of the overshoot observed numerically. Furthermore, it exhibits the Stokes phenomenon with the Stokes line at the boundary of the droplet, decaying like a Gaussian inside and outside the liquid with different decay lengths. In the limit of vanishing magnetic length, the shape of the overshoot is a singular double layer with a capacity that is a universal function of the filling fraction. Finally, we derive the edge dipole moment of Pfaffian FQH states. The result suggests an explicit connection between the magnitude of the dipole moment and the bulk odd viscosity.

  19. The Robotic Edge Finishing Laboratory

    SciTech Connect

    Loucks, C.S.; Selleck, C.B.

    1990-08-01

    The Robotic Edge Finishing Laboratory at Sandia National Laboratories is developing four areas of technology required for automated deburring, chamfering, and blending of machined edges: (1) the automatic programming of robot trajectories and deburring processes using information derived from a CAD database, (2) the use of machine vision for locating the workpiece coupled with force control to ensure proper tool contact, (3) robotic deburring, blending, and machining of precision chamfered edges, and (4) in-process automated inspection of the formed edge. The Laboratory, its components, integration, and results from edge finishing experiments to date are described here. Also included is a discussion of the issues regarding implementation of the technology in a production environment. 24 refs., 17 figs.

  20. Assessment of imaging with extended depth-of-field by means of the light sword lens in terms of visual acuity scale

    PubMed Central

    Kakarenko, Karol; Ducin, Izabela; Grabowiecki, Krzysztof; Jaroszewicz, Zbigniew; Kolodziejczyk, Andrzej; Mira-Agudelo, Alejandro; Petelczyc, Krzysztof; Składowska, Aleksandra; Sypek, Maciej

    2015-01-01

    We present outcomes of an imaging experiment using the refractive light sword lens (LSL) as a contact lens in an optical system that serves as a simplified model of the presbyopic eye. The results show that the LSL produces significant improvements in visual acuity of the simplified presbyopic eye model over a wide range of defocus. Therefore, this element can be an interesting alternative for the multifocal contact and intraocular lenses currently used in ophthalmology. The second part of the article discusses possible modifications of the LSL profile in order to render it more suitable for fabrication and ophthalmological applications. PMID:26137376

  1. Edge-on Galaxy

    NASA Technical Reports Server (NTRS)

    1999-01-01

    NASA's Hubble Space Telescope has imaged an unusual edge-on galaxy, revealing remarkable details of its warped dusty disc and showing how colliding galaxies trigger the birth of new stars.

    The image, taken by Hubble's Wide Field and Planetary Camera 2 (WFPC2), is online at http://heritage.stsci.edu and http://www.jpl.nasa.gov/images/wfpc. The camera was designed and built by NASA's Jet Propulsion Laboratory, Pasadena, Calif. During observations of the galaxy, the camera passed a milestone, taking its 100,000th image since shuttle astronauts installed it in Hubble in 1993.

    The dust and spiral arms of normal spiral galaxies, like our Milky Way, look flat when seen edge- on. The new image of the galaxy ESO 510-G13 shows an unusual twisted disc structure, first seen in ground-based photographs taken at the European Southern Observatory in Chile. ESO 510-G13 lies in the southern constellation Hydra, some 150 million light-years from Earth. Details of the galaxy's structure are visible because interstellar dust clouds that trace its disc are silhouetted from behind by light from the galaxy's bright, smooth central bulge.

    The strong warping of the disc indicates that ESO 510-G13 has recently collided with a nearby galaxy and is in the process of swallowing it. Gravitational forces distort galaxies as their stars, gas, and dust merge over millions of years. When the disturbances die out, ESO 510-G13 will be a single galaxy.

    The galaxy's outer regions, especially on the right side of the image, show dark dust and bright clouds of blue stars. This indicates that hot, young stars are forming in the twisted disc. Astronomers believe star formation may be triggered when galaxies collide and their interstellar clouds are compressed.

    The Hubble Heritage Team used WFPC2 to observe ESO 510-G13 in April 2001. Pictures obtained through blue, green, and red filters were combined to make this color-composite image, which emphasizes the contrast between the dusty

  2. Edge-on Galaxy

    NASA Technical Reports Server (NTRS)

    1999-01-01

    NASA's Hubble Space Telescope has imaged an unusual edge-on galaxy, revealing remarkable details of its warped dusty disc and showing how colliding galaxies trigger the birth of new stars.

    The image, taken by Hubble's Wide Field and Planetary Camera 2 (WFPC2), is online at http://heritage.stsci.edu and http://www.jpl.nasa.gov/images/wfpc. The camera was designed and built by NASA's Jet Propulsion Laboratory, Pasadena, Calif. During observations of the galaxy, the camera passed a milestone, taking its 100,000th image since shuttle astronauts installed it in Hubble in 1993.

    The dust and spiral arms of normal spiral galaxies, like our Milky Way, look flat when seen edge- on. The new image of the galaxy ESO 510-G13 shows an unusual twisted disc structure, first seen in ground-based photographs taken at the European Southern Observatory in Chile. ESO 510-G13 lies in the southern constellation Hydra, some 150 million light-years from Earth. Details of the galaxy's structure are visible because interstellar dust clouds that trace its disc are silhouetted from behind by light from the galaxy's bright, smooth central bulge.

    The strong warping of the disc indicates that ESO 510-G13 has recently collided with a nearby galaxy and is in the process of swallowing it. Gravitational forces distort galaxies as their stars, gas, and dust merge over millions of years. When the disturbances die out, ESO 510-G13 will be a single galaxy.

    The galaxy's outer regions, especially on the right side of the image, show dark dust and bright clouds of blue stars. This indicates that hot, young stars are forming in the twisted disc. Astronomers believe star formation may be triggered when galaxies collide and their interstellar clouds are compressed.

    The Hubble Heritage Team used WFPC2 to observe ESO 510-G13 in April 2001. Pictures obtained through blue, green, and red filters were combined to make this color-composite image, which emphasizes the contrast between the dusty

  3. Edge of a cliff

    NASA Astrophysics Data System (ADS)

    Shimizu, Yusuke; Tatsuta, Yoshiyuki

    2016-10-01

    We discuss the neutrino flavor structures in the Occam's razor approach for the Dirac neutrino mass matrices. We assume that the charged lepton mass matrix takes a diagonal base, while the right-handed Majorana neutrino mass matrix is also diagonal and we consider nine patterns of the four zero textures for the Dirac neutrinos mass matrices. We numerically analyze the left-handed Majorana neutrino mass matrices for nine patterns of the Dirac neutrino mass matrices and we find two interesting patterns where both normal and inverted neutrino mass hierarchies can be realized. We also find if the neutrino mass is normal hierarchy, this scenario will be likely to be excluded by the measurements of the Dirac CP violating phase in the T2K and NO νA neutrino experiments, for instance. On the other hand, if the neutrino mass is inverted hierarchy, this scenario will be also likely to be excluded by the measurements of neutrinoless double beta decay experiments, e.g., K amLAND-Zen experiment.

  4. Double Layers in Astrophysics

    NASA Technical Reports Server (NTRS)

    Williams, Alton C. (Editor); Moorehead, Tauna W. (Editor)

    1987-01-01

    Topics addressed include: laboratory double layers; ion-acoustic double layers; pumping potential wells; ion phase-space vortices; weak double layers; electric fields and double layers in plasmas; auroral double layers; double layer formation in a plasma; beamed emission from gamma-ray burst source; double layers and extragalactic jets; and electric potential between plasma sheet clouds.

  5. Double screening

    SciTech Connect

    Gratia, Pierre; Hu, Wayne; Joyce, Austin; Ribeiro, Raquel H.

    2016-06-15

    Attempts to modify gravity in the infrared typically require a screening mechanism to ensure consistency with local tests of gravity. These screening mechanisms fit into three broad classes; we investigate theories which are capable of exhibiting more than one type of screening. Specifically, we focus on a simple model which exhibits both Vainshtein and kinetic screening. We point out that due to the two characteristic length scales in the problem, the type of screening that dominates depends on the mass of the sourcing object, allowing for different phenomenology at different scales. We consider embedding this double screening phenomenology in a broader cosmological scenario and show that the simplest examples that exhibit double screening are radiatively stable.

  6. Reduction of airfoil trailing edge noise by trailing edge blowing

    NASA Astrophysics Data System (ADS)

    Gerhard, T.; Erbslöh, S.; Carolus, T.

    2014-06-01

    The paper deals with airfoil trailing edge noise and its reduction by trailing edge blowing. A Somers S834 airfoil section which originally was designed for small wind turbines is investigated. To mimic realistic Reynolds numbers the boundary layer is tripped on pressure and suction side. The chordwise position of the blowing slot is varied. The acoustic sources, i.e. the unsteady flow quantities in the turbulent boundary layer in the vicinity of the trailing edge, are quantified for the airfoil without and with trailing edge blowing by means of a large eddy simulation and complementary measurements. Eventually the far field airfoil noise is measured by a two-microphone filtering and correlation and a 40 microphone array technique. Both, LES-prediction and measurements showed that a suitable blowing jet on the airfoil suction side is able to reduce significantly the turbulence intensity and the induced surface pressure fluctuations in the trailing edge region. As a consequence, trailing edge noise associated with a spectral hump around 500 Hz could be reduced by 3 dB. For that a jet velocity of 50% of the free field velocity was sufficient. The most favourable slot position was at 90% chord length.

  7. Oscillations at B Ring Edge

    NASA Image and Video Library

    2010-11-01

    This image obtained by NASA Cassini spacecraft of the outer edge of Saturn?s B ring, reveals the combined effects of a tugging moon and oscillations that can naturally occur in disks like Saturn rings and spiral galaxies.

  8. Fast tracking using edge histograms

    NASA Astrophysics Data System (ADS)

    Rokita, Przemyslaw

    1997-04-01

    This paper proposes a new algorithm for tracking objects and objects boundaries. This algorithm was developed and applied in a system used for compositing computer generated images and real world video sequences, but can be applied in general in all tracking systems where accuracy and high processing speed are required. The algorithm is based on analysis of histograms obtained by summing along chosen axles pixels of edge segmented images. Edge segmentation is done by spatial convolution using gradient operator. The advantage of such an approach is that it can be performed in real-time using available on the market hardware convolution filters. After edge extraction and histograms computation, respective positions of maximums in edge intensity histograms, in current and previous frame, are compared and matched. Obtained this way information about displacement of histograms maximums, can be directly converted into information about changes of target boundaries positions along chosen axles.

  9. Edge Fracture in Complex Fluids

    NASA Astrophysics Data System (ADS)

    Hemingway, Ewan J.; Kusumaatmaja, Halim; Fielding, Suzanne M.

    2017-07-01

    We study theoretically the edge fracture instability in sheared complex fluids, by means of linear stability analysis and direct nonlinear simulations. We derive an exact analytical expression for the onset of edge fracture in terms of the shear-rate derivative of the fluid's second normal stress difference, the shear-rate derivative of the shear stress, the jump in shear stress across the interface between the fluid and the outside medium (usually air), the surface tension of that interface, and the rheometer gap size. We provide a full mechanistic understanding of the edge fracture instability, carefully validated against our simulations. These findings, which are robust with respect to choice of rheological constitutive model, also suggest a possible route to mitigating edge fracture, potentially allowing experimentalists to achieve and accurately measure flows stronger than hitherto possible.

  10. Edge Fracture in Complex Fluids.

    PubMed

    Hemingway, Ewan J; Kusumaatmaja, Halim; Fielding, Suzanne M

    2017-07-14

    We study theoretically the edge fracture instability in sheared complex fluids, by means of linear stability analysis and direct nonlinear simulations. We derive an exact analytical expression for the onset of edge fracture in terms of the shear-rate derivative of the fluid's second normal stress difference, the shear-rate derivative of the shear stress, the jump in shear stress across the interface between the fluid and the outside medium (usually air), the surface tension of that interface, and the rheometer gap size. We provide a full mechanistic understanding of the edge fracture instability, carefully validated against our simulations. These findings, which are robust with respect to choice of rheological constitutive model, also suggest a possible route to mitigating edge fracture, potentially allowing experimentalists to achieve and accurately measure flows stronger than hitherto possible.

  11. Edge equilibrium code for tokamaks

    SciTech Connect

    Li, Xujing; Drozdov, Vladimir V.

    2014-01-15

    The edge equilibrium code (EEC) described in this paper is developed for simulations of the near edge plasma using the finite element method. It solves the Grad-Shafranov equation in toroidal coordinate and uses adaptive grids aligned with magnetic field lines. Hermite finite elements are chosen for the numerical scheme. A fast Newton scheme which is the same as implemented in the equilibrium and stability code (ESC) is applied here to adjust the grids.

  12. Multiple pre-edge structures in Cu K -edge x-ray absorption spectra of high- Tc cuprates revealed by high-resolution x-ray absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Gougoussis, C.; Rueff, J.-P.; Calandra, M.; D'Astuto, M.; Jarrige, I.; Ishii, H.; Shukla, A.; Yamada, I.; Azuma, M.; Takano, M.

    2010-06-01

    Using high-resolution x-ray absorption spectroscopy and state-of-the-art electronic structure calculations we demonstrate that the pre-edge region at the Cu K edge of high- Tc cuprates is composed of several excitations invisible in standard x-ray absorption spectra. We consider in detail the case of Ca2-xCuO2Cl2 and show that the many pre-edge excitations (two for c -axis polarization, four for in-plane polarization and out-of-plane incident x-ray momentum) are dominated by off-site transitions and intersite hybridization. This demonstrates the relevance of approaches beyond the single-site model for the description of the pre edges of correlated materials. Finally, we show the occurrence of a doubling of the main edge peak that is most visible when the polarization is along the c axis. This doubling, that has not been seen in any previous absorption data in cuprates, is not reproduced by first-principles calculations. We suggest that this peak is due to many-body charge-transfer excitations while all the other visible far-edge structures are single particle in origin. Our work indicates that previous interpretations of the Cu K -edge x-ray absorption spectra in high- Tc cuprates can be profitably reconsidered.

  13. Double Eclipse

    NASA Image and Video Library

    2016-09-01

    NASA's Solar Dynamics Observatory (SDO) saw both the Moon (upper right) and the Earth (upper left) partially block the sun (Sept. 1, 2016 at 7:33 UT). Just before this image was taken, the Earth totally blocked the sun for a while. SDO orbits 22,000 miles above the Earth in a highly elliptical orbit that sometimes puts the Moon or Earth in front of the sun. The sun image was taken in a wavelength of extreme ultraviolet light. Only once before have both been there at the same time. Note that the edge of the moon is quite crisp because it has no atmosphere. Movies are available at the Photojournal. http://photojournal.jpl.nasa.gov/catalog/PIA21028

  14. Edge instabilities of topological superconductors

    NASA Astrophysics Data System (ADS)

    Hofmann, Johannes S.; Assaad, Fakher F.; Schnyder, Andreas P.

    2016-05-01

    Nodal topological superconductors display zero-energy Majorana flat bands at generic edges. The flatness of these edge bands, which is protected by time-reversal and translation symmetry, gives rise to an extensive ground-state degeneracy. Therefore, even arbitrarily weak interactions lead to an instability of the flat-band edge states towards time-reversal and translation-symmetry-broken phases, which lift the ground-state degeneracy. We examine the instabilities of the flat-band edge states of dx y-wave superconductors by performing a mean-field analysis in the Majorana basis of the edge states. The leading instabilities are Majorana mass terms, which correspond to coherent superpositions of particle-particle and particle-hole channels in the fermionic language. We find that attractive interactions induce three different mass terms. One is a coherent superposition of imaginary s -wave pairing and current order, and another combines a charge-density-wave and finite-momentum singlet pairing. Repulsive interactions, on the other hand, lead to ferromagnetism together with spin-triplet pairing at the edge. Our quantum Monte Carlo simulations confirm these findings and demonstrate that these instabilities occur even in the presence of strong quantum fluctuations. We discuss the implications of our results for experiments on cuprate high-temperature superconductors.

  15. Universal edge information from wave-function deformation

    NASA Astrophysics Data System (ADS)

    Ho, Wen Wei; Cincio, Lukasz; Moradi, Heidar; Vidal, Guifre

    2017-06-01

    It is well known that the bulk physics of a topological phase constrains its possible edge physics through the bulk-edge correspondence. Therefore, the different types of edge theories that a topological phase can host constitute a universal piece of data which can be used to characterize topological order. In this paper, we argue that, beginning from only the fixed-point wave function (FPW) of a nonchiral topological phase and by locally deforming it, all possible edge theories can be extracted from its entanglement Hamiltonian (EH). We give a general argument, and concretely illustrate our claim by deforming the FPW of the Wen-plaquette model, the quantum double of Z2. In that case, we show that the possible EHs of the deformed FPW reflect the known possible types of edge theories, which are generically gapped but gapless if translational symmetry is preserved. We stress that our results do not require an underlying Hamiltonian—thus, this lends support to the notion that a topological phase is indeed characterized by only a set of quantum states and can be studied through its FPWs.

  16. Energy relaxation at quantum Hall edge

    NASA Astrophysics Data System (ADS)

    Levkivskyi, Ivan P.; Sukhorukov, Eugene V.

    2012-02-01

    In this work, we address the recent experiments [C. Altimiras , Nat. Phys.1745-247310.1038/nphys1429 6, 34 (2010); H. le Sueur , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.105.056803 105, 056803 (2010);C. Altimiras , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.105.226804 105, 226804 (2010)], where an electron distribution function at the quantum Hall (QH) edge at filling factor ν=2 has been measured with high precision. It has been reported that the energy of electrons injected into one of the two chiral edge channels with the help of a quantum point contact (QPC) is equally distributed between them, in agreement with earlier predictions, one being based on the Fermi gas approach [A. M. Lunde , Phys. Rev. BPRBMDO1098-012110.1103/PhysRevB.81.041311 81, 041311(R) (2010)] and the other utilizing the Luttinger-liquid theory [P. Degiovanni , Phys. Rev. BPRBMDO1098-012110.1103/PhysRevB.81.121302 81, 121302(R) (2010)]. We argue that the physics of the energy relaxation process at the QH edge may in fact be more rich, providing the possibility for discriminating between two physical pictures in experiment. Namely, using the recently proposed nonequilibrium bosonization technique [I. P. Levkivskyi , Phys. Rev. Lett., PRLTAO0031-900710.1103/PhysRevLett.103.036801 103, 036801 (2009)], we evaluate the electron distribution function and find that the initial “double-step” distribution created at a QPC evolves through several intermediate asymptotics before reaching eventual equilibrium state. At short distances, the distribution function is found to be asymmetric due to non-Gaussian current noise effects. At larger distances, where noise becomes Gaussian, the distribution function acquires symmetric Lorentzian shape. Importantly, in the regime of low QPC transparencies T, the width of the Lorentzian scales linearly with T, in contrast to the case of equilibrium Fermi distribution, the width of which scales as T. Therefore, we propose to do measurements at

  17. On the Edge: Haptic Discrimination of Edge Sharpness

    PubMed Central

    Skinner, Andy L.; Kent, Christopher; Rossiter, Jonathan M.; Benton, Christopher P.; Groen, Martin G. M.; Noyes, Jan M.

    2013-01-01

    The increasing ubiquity of haptic displays (e.g., smart phones and tablets) necessitates a better understanding of the perceptual capabilities of the human haptic system. Haptic displays will soon be capable of locally deforming to create simple 3D shapes. This study investigated the sensitivity of our haptic system to a fundamental component of shapes: edges. A novel set of eight high quality shape stimuli with test edges that varied in sharpness were fabricated in a 3D printer. In a two alternative, forced choice task, blindfolded participants were presented with two of these shapes side by side (one the reference, the other selected randomly from the remaining set of seven) and after actively exploring the test edge of each shape with the tip of their index finger, reported which shape had the sharper edge. We used a model selection approach to fit optimal psychometric functions to performance data, and from these obtained just noticeable differences and Weber fractions. In Experiment 1, participants performed the task with four different references. With sharpness defined as the angle at which one surface meets the horizontal plane, the four JNDs closely followed Weber’s Law, giving a Weber fraction of 0.11. Comparisons to previously reported Weber fractions from other haptic manipulations (e.g. amplitude of vibration) suggests we are sufficiently sensitive to changes in edge sharpness for this to be of potential utility in the design of future haptic displays. In Experiment 2, two groups of participants performed the task with a single reference but different exploration strategies; one was limited to a single touch, the other unconstrained and free to explore as they wished. As predicted, the JND in the free exploration condition was lower than that in the single touch condition, indicating exploration strategy affects sensitivity to edge sharpness. PMID:24023852

  18. Edge-Aware BMA Filters.

    PubMed

    Guang Deng

    2016-01-01

    There has been continuous research in edge-aware filters which have found many applications in computer vision and image processing. In this paper, we propose a principled-approach for the development of edge-aware filters. The proposed approach is based on two well-established principles: 1) optimal parameter estimation and 2) Bayesian model averaging (BMA). Using this approach, we formulate the problem of filtering a pixel in a local pixel patch as an optimal estimation problem. Since a pixel belongs to multiple local patches, there are multiple estimates of the same pixel. We combine these estimates into a final estimate using BMA. We demonstrate the versatility of this approach by developing a family of BMA filters based on different settings of cost functions and log-likelihood and log-prior functions. We also present a new interpretation of the guided filter and develop a BMA guided filter which includes the guided filter as a special case. We show that BMA filters can produce similar smoothing results as those of the state-of-the-art edge-aware filters. Two BMA filters are computationally as efficient as the guided filter which is one of the fastest edge-aware filters. We also demonstrate that the BMA guided filter is better than the guided filter in preserving sharp edges. A new feature of the BMA guided filter is that the filtered image is similar to that produced by a clustering process.

  19. Flap-Edge Blowing Experiments

    NASA Technical Reports Server (NTRS)

    Gaeta, R. J.; Englar, R. J.; Ahuja, K. K.

    2003-01-01

    This Appendix documents the salient results from an effort to mitigate the so-called flap-edge noise generated at the split between a flap edge that is deployed and the undeployed flap. Utilizing a Coanda surface installed at the flap edge, steady blowing was used in an attempt to diminish the vortex strength resulting from the uneven lift distribution. The strength of this lifting vortex was augmented by steady blowing over the deployed flap. The test article for this study was the same 2D airfoil used in the steady blowing program reported earlier (also used in pulsed blowing tests, see Appendix G), however its trailing edge geometry was modified. An exact duplicate of the airfoil shape was made out of fiberglass with no flap, and in the clean configuration. It was attached to the existing airfoil to make an airfoil that has half of its flap deployed and half un-deployed. Figure 1 shows a schematic of the planform showing the two areas where steady blowing was introduced. The flap-edge blowing or the auxiliary blowing was in the direction normal to the freestream velocity vector. Slot heights for the blowing chambers were on the order of 0.0 14 inches.

  20. Reduction of wing rock amplitudes using leading-edge vortex manipulations

    NASA Technical Reports Server (NTRS)

    Walton, James; Katz, Joseph

    1992-01-01

    A mechanically operated leading edge flap system was used to perturb leading edge vortex position on a free-to-roll double-delta wing. The motion of the flaps was synchronized with the wing rolling oscillations and the effect of the phase shift between the oscillations of the wing and the flaps was investigated. Experimental results indicated that this simple approach was effective in reducing the amplitude of the unintended rolling motion and its implementation to actual airplane configurations is rather simple.

  1. Supporting interactive graph exploration using edge plucking

    NASA Astrophysics Data System (ADS)

    Wong, Nelson; Carpendale, Sheelagh

    2007-01-01

    Excessive edge density in graphs can cause serious readability issues, which in turn can make the graphs difficult to understand or even misleading. Recently, we introduced the idea of providing tools that offer interactive edge bending as a method by which edge congestion can be disambiguated. We extend this direction, presenting a new tool, Edge Plucking, which offers new interactive methods to clarify node-edge relationships. Edge Plucking expands the number of situations in which interactive graph exploration tools can be used to address edge congestion.

  2. Role of Edges in Complex Network Epidemiology

    NASA Astrophysics Data System (ADS)

    Zhang, Hao; Jiang, Zhi-Hong; Wang, Hui; Xie, Fei; Chen, Chao

    2012-09-01

    In complex network epidemiology, diseases spread along contacting edges between individuals and different edges may play different roles in epidemic outbreaks. Quantifying the efficiency of edges is an important step towards arresting epidemics. In this paper, we study the efficiency of edges in general susceptible-infected-recovered models, and introduce the transmission capability to measure the efficiency of edges. Results show that deleting edges with the highest transmission capability will greatly decrease epidemics on scale-free networks. Basing on the message passing approach, we get exact mathematical solution on configuration model networks with edge deletion in the large size limit.

  3. X-ray absorption near edge spectroscopy at the Mn K-edge in highly homogeneous GaMnN diluted magnetic semiconductors

    NASA Astrophysics Data System (ADS)

    Sancho-Juan, O.; Cantarero, A.; Martínez-Criado, G.; Olguín, D.; Garro, N.; Cros, A.; Salomé, M.; Susini, J.; Dhar, S.; Ploog, K.

    We have studied by X-ray absorption spectroscopy the local environment of Mn in highly homogeneous Ga1-xMnxN (0.06 < x < 0.14) thin epilayers grown by molecular beam epitaxy on [0001] SiC substrates. The measurements were performed in fluorescence mode around the Ga and Mn K-edges. In this report, we focus our attention to the X-ray absorption near edge spectroscopy (XANES) results. The comparison of the XANES spectra corresponding to the Ga and Mn edges indicates that Mn is substitutional to Ga in all samples studied. The XANES spectra measured at the Mn absorption edge shows in the near-edge region a double peak and a shoulder below the absorption edge and the main absorption peak after the edge, separated around 15 eV above the pre-edge structure. We have compared the position of the edge with that of MnO (Mn2+) and Mn2O3 (Mn3+). All samples studied present the same Mn oxidation state, 2+. In order to interprete the near-edge structure, we have performed ab initio calculations with a 2 × 2 × 1 supercell (?6% Mn) using the full potential linear augmented plane wave method as implemented in the Wien2k code. The calculations show the appearance of Mn anti-bonding t2g bands, which are responsible for the pre-edge absorption. The shoulder and main absorption peaks are due to transitions from the valence band 1s-states of Mn to the p-contributions of the conduction bands.

  4. Edge enhanced morphology for infrared image analysis

    NASA Astrophysics Data System (ADS)

    Bai, Xiangzhi; Liu, Haonan

    2017-01-01

    Edge information is one of the critical information for infrared images. Morphological operators have been widely used for infrared image analysis. However, the edge information in infrared image is weak and the morphological operators could not well utilize the edge information of infrared images. To strengthen the edge information in morphological operators, the edge enhanced morphology is proposed in this paper. Firstly, the edge enhanced dilation and erosion operators are given and analyzed. Secondly, the pseudo operators which are derived from the edge enhanced dilation and erosion operators are defined. Finally, the applications for infrared image analysis are shown to verify the effectiveness of the proposed edge enhanced morphological operators. The proposed edge enhanced morphological operators are useful for the applications related to edge features, which could be extended to wide area of applications.

  5. Shape-dependent canny edge detector

    NASA Astrophysics Data System (ADS)

    Panetta, Karen A.; Agaian, Sos S.; Nercessian, Shahan C.; Almunstashri, Ali A.

    2011-08-01

    Edges characterize the boundaries of objects in images and are informative structural cues for computer vision and target/object detection and recognition systems. The Canny edge detector is widely regarded as the edge detection standard. It is fairly adaptable to different environments, as its parametric nature attempts to tailor the detection of edges based on image-dependent characteristics or the particular requirements of a given implementation. Though it has been used in a myriad of image processing tasks, the Canny edge detector is still vulnerable to edge losses, localization errors, and noise sensitivity. These issues are largely due to the key tradeoff made in the scale and size of the edge detection filters used by the algorithm. Small-scaled filters are sensitive to edges but also to noise, whereas large-scaled filters are robust to noise but could filter out fine details. In this paper, novel edge detection kernel generalizations and a shape-dependent edge detector are introduced to alleviate these shortcomings. While most standard edge detection algorithms are based on convolving the input image with fixed size square kernels, this paper will illustrate the benefits of different filter sizes, and more importantly, different kernel shapes for edge detection. Moreover, new edge fusion methods are introduced to more effectively combine the individual edge responses. Existing edge detectors, including the Canny edge detector, can be obtained from the generalized edge detector by specifying corresponding parameters and kernel shapes. The proposed representations and edge detector have been qualitatively and quantitatively evaluated on several different types of image data. Computer simulations demonstrate that nonsquare kernel approaches can outperform square kernel approaches such as Canny, Sobel, Prewitt, Roberts, and others, providing better tradeoffs between noise rejection, accurate edge localization, and resolution. Where possible, Pratt's figure of

  6. Laplacian operator-based edge detectors.

    PubMed

    Wang, Xin

    2007-05-01

    Laplacian operator is a second derivative operator often used in edge detection. Compared with the first derivative-based edge detectors such as Sobel operator, the Laplacian operator may yield better results in edge localization. Unfortunately, the Laplacian operator is very sensitive to noise. In this paper, based on the Laplacian operator, a model is introduced for making some edge detectors. Also, the optimal threshold is introduced for obtaining a Maximum a Posteriori (MAP) estimate of edges.

  7. Acoustic diffraction by deformed edges of finite length: theory and experiment.

    PubMed

    Stanton, Timothy K; Chu, Dezhang; Norton, Guy V

    2007-12-01

    The acoustic diffraction by deformed edges of finite length is described analytically and in the frequency domain through use of an approximate line-integral formulation. The formulation is based on the diffraction per unit length of an infinitely long straight edge, which inherently limits the accuracy of the approach. The line integral is written in terms of the diffraction by a generalized edge, in that the "edge" can be a single edge or multiple closely spaced edges. Predictions based on an exact solution to the impenetrable infinite knife edge are used to estimate diffraction by the edge of a thin disk and compared with calculations based on the T-matrix approach. Predictions are then made for the more complex geometry involving an impenetrable thick disk. These latter predictions are based on an approximate formula for double-edge diffraction [Chu et al., J. Acoust. Soc. Am. 122, 3177 (2007)] and are compared with laboratory data involving individual elastic (aluminum) disks spanning a range of diameters and submerged in water. The results of this study show this approximate line-integral approach to be versatile and applicable over a range of conditions.

  8. Edge transport in the trivial phase of InAs/GaSb

    NASA Astrophysics Data System (ADS)

    Nichele, Fabrizio; Suominen, Henri J.; Kjaergaard, Morten; Marcus, Charles M.; Sajadi, Ebrahim; Folk, Joshua A.; Qu, Fanming; Beukman, Arjan J. A.; de Vries, Folkert K.; van Veen, Jasper; Nadj-Perge, Stevan; Kouwenhoven, Leo P.; Nguyen, Binh-Minh; Kiselev, Andrey A.; Yi, Wei; Sokolich, Marko; Manfra, Michael J.; Spanton, Eric M.; Moler, Kathryn A.

    2016-08-01

    We present transport and scanning SQUID measurements on InAs/GaSb double quantum wells, a system predicted to be a two-dimensional topological insulator. Top and back gates allow independent control of density and band offset, allowing tuning from the trivial to the topological regime. In the trivial regime, bulk conductivity is quenched but transport persists along the edges, superficially resembling the predicted helical edge-channels in the topological regime. We characterize edge conduction in the trivial regime in a wide variety of sample geometries and measurement configurations, as a function of temperature, magnetic field, and edge length. Despite similarities to studies claiming measurements of helical edge channels, our characterization points to a non-topological origin for these observations.

  9. Failure During Sheared Edge Stretching

    NASA Astrophysics Data System (ADS)

    Levy, B. S.; van Tyne, C. J.

    2008-12-01

    Failure during sheared edge stretching of sheet steels is a serious concern, especially in advanced high-strength steel (AHSS) grades. The shearing process produces a shear face and a zone of deformation behind the shear face, which is the shear-affected zone (SAZ). A failure during sheared edge stretching depends on prior deformation in the sheet, the shearing process, and the subsequent strain path in the SAZ during stretching. Data from laboratory hole expansion tests and hole extrusion tests for multiple lots of fourteen grades of steel were analyzed. The forming limit curve (FLC), regression equations, measurement uncertainty calculations, and difference calculations were used in the analyses. From these analyses, an assessment of the primary factors that contribute to the fracture during sheared edge stretching was made. It was found that the forming limit strain with consideration of strain path in the SAZ is a major factor that contributes to the failure of a sheared edge during stretching. Although metallurgical factors are important, they appear to play a somewhat lesser role.

  10. The Problem of the Edge.

    ERIC Educational Resources Information Center

    Faatz, Judith A.

    1998-01-01

    Describes a field study in a local ecosystem which allows high school students to investigate the edge effect, where a meadow and a forest meet. Students measure soil moisture content, soil temperature, air temperature, relative humidity, wind intensity, and illumination level. Teachers can help students apply their findings to understand problems…

  11. The Problem of the Edge.

    ERIC Educational Resources Information Center

    Faatz, Judith A.

    1998-01-01

    Describes a field study in a local ecosystem which allows high school students to investigate the edge effect, where a meadow and a forest meet. Students measure soil moisture content, soil temperature, air temperature, relative humidity, wind intensity, and illumination level. Teachers can help students apply their findings to understand problems…

  12. Isolation of microsatellite markers and analysis of genetic diversity among east Atlantic populations of the sword razor shell Ensis siliqua: a tool for population management.

    PubMed

    Arias-Pérez, Alberto; Fernández-Tajes, Juan; Gaspar, Miguel B; Méndez, Josefina

    2012-06-01

    The sword razor shell Ensis siliqua (Linnaeus, 1758) is found mainly from Norway to the Atlantic coast of the Iberian Peninsula. It is intensively caught in Europe, being highly appreciated as seafood. To help in its conservation and management, five microsatellite markers were isolated and genetic variation was analyzed in samples from Ireland, Spain, and Portugal. The highly significant differentiation (θ = 0.287, P < 0.001) observed was mainly due to differences between samples from Irish and Iberian Peninsula localities, except Aveiro (its sample resembled the Irish samples, and it may be predominantly self-recruiting). These groups of samples showed significant differences in allelic richness that could be related to harvesting intensity. Moreover, microsatellites detected low but significant differentiation between Iberian localities (Celeiro and Olhão), and Aveiro differed significantly from Strangford Lough. Overall, results suggest that two independently evolving regions exist and that management strategies should be designed for each region.

  13. A Little Bit of Sugar Helps the Pill Go Down: Resilience, Peace, and Family Planning: Comment on "The Pill Is Mightier Than the Sword".

    PubMed

    De Souza, Roger-Mark

    2015-10-04

    The article by Potts et al, "The Pill is Mightier than the Sword," points out that family planning has an important role to play in building peace by increasing women's empowerment and their agency, ultimately helping peacebuilding efforts. Evidence has demonstrated that family planning programs are cost effective, produce quick results, help women and couples meet their desired fertility levels, and produce a multitude of benefits around economic productivity, community engagement, conservation, resilience, and peacebuilding. In order for policy audiences from a variety of sectors, including conflict and peacebuilding, to appreciate these benefits, it is important to find common ground and articulate co-benefits that will help them appreciate and value the role of family planning, as it were, give them sugar to help the pill go down. This commentary examines how resilience, peacebuilding and family planning efforts need to focus on co-benefits in order to build on the successful interventions and opportunities that Potts et al highlight.

  14. Development of edge effects around experimental ecosystem hotspots is affected by edge density and matrix type

    USDA-ARS?s Scientific Manuscript database

    Ecological edge effects are sensitive to landscape context. In particular, edge effects can be altered by matrix type and by the presence of other nearby edges. We experimentally altered patch configurations in an African savanna to determine how edge density and matrix type influence edge effect de...

  15. Edge-modulated perpendicular magnetic anisotropy in [Co/Pd]n and L10-FePt thin film wires

    NASA Astrophysics Data System (ADS)

    Zhang, Jinshuo; Ho, Pin; Currivan-Incorvia, Jean Anne; Siddiqui, Saima A.; Baldo, Marc A.; Ross, Caroline A.

    2015-11-01

    Thickness modulation at the edges of nanostructured magnetic thin films is shown to have important effects on their perpendicular magnetic anisotropy. Thin film wires with tapered edges were made from [Co/Pd]20 multilayers or L10-FePt films using liftoff with a double-layer resist. The effect of edge taper on the reversal process was studied using magnetic force microscopy and micromagnetic modeling. In [Co/Pd]20, the anisotropy was lower in the tapered edge regions which switched at a lower reverse field compared to the center of the wire. The L10-FePt wires showed opposite behavior with the tapered regions exhibiting higher anisotropy.

  16. Double inflation

    SciTech Connect

    Silk, J.; Turner, M.S.

    1986-04-01

    The Zel'dovich spectrum of adiabatic density perturbations is a generic prediction of inflation. There is increasing evidence that when the spectrum is normalized by observational data on small scales, there is not enough power on large scales to account for the observed large-scale structure in the Universe. Decoupling the spectrum on large and small scales could solve this problem. As a means of decoupling the large and small scales we propose double inflation (i.e., two episodes of inflation). In this scenario the spectrum on large scales is determined by the first episode of inflation and those on small scales by a second episode of inflation. We present three models for such a scenario. By nearly saturating the large angular-scale cosmic microwave anisotropy bound, we can easily account for the observed large-scale structure. We take the perturbations on small scales to be very large, deltarho/rho approx. = 0.1 to 0.01, which results in the production of primordial black holes (PBHs), early formation of structure, reionization of the Universe, and a rich array of astrophysical events. The ..cap omega..-problem is also addressed by our scenario. Allowing the density perturbations produced by the second episode of inflation to be large also lessens the fine-tuning required in the scalar potential and makes reheating much easier. We briefly speculate on the possibility that the second episode of inflation proceeds through the nucleation of bubbles, which today manifest themselves as empty bubbles whose surfaces are covered with galaxies. 37 refs., 1 fig.

  17. Seeing Double

    NASA Astrophysics Data System (ADS)

    Pesic, Peter

    2003-10-01

    The separateness and connection of individuals is perhaps the central question of human life: What, exactly, is my individuality? To what degree is it unique? To what degree can it be shared, and how? To the many philosophical and literary speculations about these topics over time, modern science has added the curious twist of quantum theory, which requires that the elementary particles of which everything consists have no individuality at all. All aspects of chemistry depend on this lack of individuality, as do many branches of physics. From where, then, does our individuality come? In Seeing Double, Peter Pesic invites readers to explore this intriguing set of questions. He draws on literary and historical examples that open the mind (from Homer to Martin Guerre to Kafka), philosophical analyses that have helped to make our thinking and speech more precise, and scientific work that has enabled us to characterize the phenomena of nature. Though he does not try to be all-inclusive, Pesic presents a broad range of ideas, building toward a specific point of view: that the crux of modern quantum theory is its clash with our ordinary concept of individuality. This represents a departure from the usual understanding of quantum theory. Pesic argues that what is bizarre about quantum theory becomes more intelligible as we reconsider what we mean by individuality and identity in ordinary experience. In turn, quantum identity opens a new perspective on us. Peter Pesic is a Tutor and Musician-in-Residence at St. John's College, Santa Fe, New Mexico. He has a Ph.D. in physics from Stanford University.

  18. Nature of Graphene Edges: A Review

    NASA Astrophysics Data System (ADS)

    Acik, Muge; Chabal, Yves J.

    2011-07-01

    Graphene edges determine the optical, magnetic, electrical, and electronic properties of graphene. In particular, termination, chemical functionalization and reconstruction of graphene edges leads to crucial changes in the properties of graphene, so control of the edges is critical to the development of applications in electronics, spintronics and optoelectronics. Up to date, significant advances in studying graphene edges have directed various smart ways of controlling the edge morphology. Though, it still remains as a major challenge since even minor deviations from the ideal shape of the edges significantly deteriorate the material properties. In this review, we discuss the fundamental edge configurations together with the role of various types of edge defects and their effects on graphene properties. Indeed, we highlight major demanding challenges to find the most suitable technique to characterize graphene edges for numerous device applications such as transistors, sensors, actuators, solar cells, light-emitting displays, and batteries in graphene technology.

  19. Double Your Major, Double Your Return?

    ERIC Educational Resources Information Center

    Del Rossi, Alison F.; Hersch, Joni

    2008-01-01

    We use the 2003 National Survey of College Graduates to provide the first estimates of the effect on earnings of having a double major. Overall, double majoring increases earnings by 2.3% relative to having a single major among college graduates without graduate degrees. Most of the gains from having a double major come from choosing fields across…

  20. Co-Ethnic Network, Social Class, and Heritage Language Maintenance among Chinese Immigrant Families

    ERIC Educational Resources Information Center

    Zhang, Donghui

    2012-01-01

    This ethnographic study investigated heritage language maintenance among two distinct groups of Chinese immigrant families (Mandarin and Fujianese) from the social network perspective. The results indicated that a co-ethnic network could be a double-edged sword, which works differently on children from different social classes. While the Mandarin…

  1. Postmodernity or High Modernity? Emerging Approaches in the New History of Education.

    ERIC Educational Resources Information Center

    Escolano, Agustin

    1996-01-01

    Compares and contrasts two emerging approaches to educational historical research. Reveals a double-edged sword in that while these approaches open up the field to a wide array of subject matter and styles of inquiry, they also may weaken the epistemological stature of the discipline. (MJP)

  2. Language at a Distance: Sharpening a Communication Tool in the Online Classroom

    ERIC Educational Resources Information Center

    Hannan, Annika

    2009-01-01

    Both immensely powerful and entirely fickle, language in online instruction is a double-edged sword. A potent intermediary between instructor and students, and among students themselves, language is a key tool in online learning. It carries and cultivates information. It builds knowledge and self-awareness. It brings learners together in a…

  3. [Study on the function and influence of hi-tech on medical and health undertakings development in China].

    PubMed

    He, Jing; Chi, Hui; Yang, Guozhong

    2010-05-01

    The invention and use of science and technology have always been a double-edged sword. The paper analysed the function and influence of medical hi-tech on medical and health undertakings development in China, and gives opinions on how to treat medical hi-tech correctly, so as to provide reference for the use and supervision of medical hi-tech.

  4. Factors Contributed by Community Organizations to the Motivation of Teachers in Rural Punjab, Pakistan, and Implications for the Quality of Teaching

    ERIC Educational Resources Information Center

    Barrs, J.

    2005-01-01

    The double-edged sword of Jomtien (1990), which emphasized access to education, and of Dakar (2000), which placed additional emphasis on the quality of education, the Holy Grail, provides the context for the expansion of education in developing countries. One of the most frequently espoused ingredients for success is good governance. The…

  5. The Effect of Computerized System Feedback Availability during Executive Function Training

    ERIC Educational Resources Information Center

    Yuviler-Gavish, Nirit; Krisher, Hagit

    2016-01-01

    Computerized training systems offer a promising new direction in the training of executive functions, in part because they can easily be designed to offer feedback to learners. Yet, feedback is a double-edged sword, serving a positive motivational role while at the same time carrying the risk that learners may become dependent on the feedback they…

  6. Analyzing the Cognitive Skills and Inquiry

    ERIC Educational Resources Information Center

    Stafford, Tish

    2011-01-01

    The Common Core Standards (CCS) movement represents a double-edged sword for school librarians. On the one hand, it gives prominence to inquiry skills and interdisciplinary collaboration, reinforcing the profession's efforts to infuse inquiry into the curriculum through collaborative planning and co-instruction between classroom teachers and…

  7. Educational Testing in America: What's Right, What's Wrong? A Criterion-Referenced Perspective.

    ERIC Educational Resources Information Center

    Popham, W. James

    1993-01-01

    Current successes and failures in U.S. educational measurement are reviewed, focusing on criterion-referenced testing. Pluses and minuses are listed for the following: (1) the move toward authentic assessment; (2) the dominance of criterion-referenced assessment; and (3) item response theory applications. Each area is a double-edged sword. (SLD)

  8. The Effect of Computerized System Feedback Availability during Executive Function Training

    ERIC Educational Resources Information Center

    Yuviler-Gavish, Nirit; Krisher, Hagit

    2016-01-01

    Computerized training systems offer a promising new direction in the training of executive functions, in part because they can easily be designed to offer feedback to learners. Yet, feedback is a double-edged sword, serving a positive motivational role while at the same time carrying the risk that learners may become dependent on the feedback they…

  9. Human Flesh Search Engine and Online Privacy.

    PubMed

    Zhang, Yang; Gao, Hong

    2016-04-01

    Human flesh search engine can be a double-edged sword, bringing convenience on the one hand and leading to infringement of personal privacy on the other hand. This paper discusses the ethical problems brought about by the human flesh search engine, as well as possible solutions.

  10. Rethinking Diversity.

    ERIC Educational Resources Information Center

    1996

    These three papers were presented at a symposium on rethinking diversity in human resource development (HRD) moderated by Neal Chalofsky at the 1996 conference of the Academy of Human Resource Development. "Diversity: A Double-Edged Sword" (Sally F. Angus) presents the notion of work force diversity through two differing perspectives in order to…

  11. Co-Ethnic Network, Social Class, and Heritage Language Maintenance among Chinese Immigrant Families

    ERIC Educational Resources Information Center

    Zhang, Donghui

    2012-01-01

    This ethnographic study investigated heritage language maintenance among two distinct groups of Chinese immigrant families (Mandarin and Fujianese) from the social network perspective. The results indicated that a co-ethnic network could be a double-edged sword, which works differently on children from different social classes. While the Mandarin…

  12. Whose Lingua Franca? The Politics of Language in Transnational Medical Education

    ERIC Educational Resources Information Center

    Kane, Tanya

    2014-01-01

    The lingua franca promoted at Weill Cornell Medical College in Qatar belongs to few as a first language. The implementation of an English-medium curriculum at Qatar's only medical school has proved a double-edged sword. Despite English being deployed out of necessity as part of a strategy geared to improve health care provision and medical…

  13. Are Plush Dorms and Fancy Food Plans Important Drivers of College Cost?

    ERIC Educational Resources Information Center

    Archibald, Robert B.; Feldman, David H.

    2011-01-01

    Like most schools, College of William and Mary is not shy about touting its amenities. The Webpage that advertises the college's housing and dining options begins with, "Wireless and Starbucks? Thomas Jefferson never had it this good." Advertising of this sort is a double-edged public-relations sword. Colleges and universities clearly want to…

  14. Are Plush Dorms and Fancy Food Plans Important Drivers of College Cost?

    ERIC Educational Resources Information Center

    Archibald, Robert B.; Feldman, David H.

    2011-01-01

    Like most schools, College of William and Mary is not shy about touting its amenities. The Webpage that advertises the college's housing and dining options begins with, "Wireless and Starbucks? Thomas Jefferson never had it this good." Advertising of this sort is a double-edged public-relations sword. Colleges and universities clearly want to…

  15. Whose Lingua Franca? The Politics of Language in Transnational Medical Education

    ERIC Educational Resources Information Center

    Kane, Tanya

    2014-01-01

    The lingua franca promoted at Weill Cornell Medical College in Qatar belongs to few as a first language. The implementation of an English-medium curriculum at Qatar's only medical school has proved a double-edged sword. Despite English being deployed out of necessity as part of a strategy geared to improve health care provision and medical…

  16. Rethinking Diversity.

    ERIC Educational Resources Information Center

    1996

    These three papers were presented at a symposium on rethinking diversity in human resource development (HRD) moderated by Neal Chalofsky at the 1996 conference of the Academy of Human Resource Development. "Diversity: A Double-Edged Sword" (Sally F. Angus) presents the notion of work force diversity through two differing perspectives in order to…

  17. Analyzing the Cognitive Skills and Inquiry

    ERIC Educational Resources Information Center

    Stafford, Tish

    2011-01-01

    The Common Core Standards (CCS) movement represents a double-edged sword for school librarians. On the one hand, it gives prominence to inquiry skills and interdisciplinary collaboration, reinforcing the profession's efforts to infuse inquiry into the curriculum through collaborative planning and co-instruction between classroom teachers and…

  18. The Social Validation of Institutional Indicators to Promote System-Wide Web Accessibility in Postsecondary Institutions

    ERIC Educational Resources Information Center

    Mariger, Heather Ann

    2011-01-01

    The Internet is an integral part of higher education today. Students, faculty, and staff must have access to the institutional web for essential activities. For persons with disabilities, the web is a double-edged sword. While an accessibly designed website can mitigate or remove barriers, an inaccessible one can make access impossible. If…

  19. Assessment of transmitral flow after mitral valve edge-to-edge repair using High-speed particle image velocimetry

    NASA Astrophysics Data System (ADS)

    Jeyhani, Morteza; Shahriari, Shahrokh; Labrosse, Michel; Kadem, Lyes

    2013-11-01

    Approximately 500,000 people in North America suffer from mitral valve regurgitation (MR). MR is a disorder of the heart in which the mitral valve (MV) leaflets do not close securely during systole. Edge-to-edge repair (EtER) technique can be used to surgically treat MR. This technique produces a double-orifice configuration for the MV. Under these un-physiological conditions, flow downstream of the MV forms a double jet structure that may disturb the intraventricular hemodynamics. Abnormal flow patterns following EtER are mainly characterized by high-shear stress and stagnation zones in the left ventricle (LV), which increase the potential of blood component damage. In this study, a custom-made prosthetic bicuspid MV was used to analyze the LV flow patterns after EtER by means of digital particle image velocimetry (PIV). Although the repair of a MV using EtER technique is an effective approach, this study confirms that EtER leads to changes in the LV flow field, including the generation of a double mitral jet flow and high shear stress regions.

  20. Quantifying edge significance on maintaining global connectivity

    PubMed Central

    Qian, Yuhua; Li, Yebin; Zhang, Min; Ma, Guoshuai; Lu, Furong

    2017-01-01

    Global connectivity is a quite important issue for networks. The failures of some key edges may lead to breakdown of the whole system. How to find them will provide a better understanding on system robustness. Based on topological information, we propose an approach named LE (link entropy) to quantify the edge significance on maintaining global connectivity. Then we compare the LE with the other six acknowledged indices on the edge significance: the edge betweenness centrality, degree product, bridgeness, diffusion importance, topological overlap and k-path edge centrality. Experimental results show that the LE approach outperforms in quantifying edge significance on maintaining global connectivity. PMID:28349923

  1. Propagating edge states in strained honeycomb lattices

    NASA Astrophysics Data System (ADS)

    Salerno, Grazia; Ozawa, Tomoki; Price, Hannah M.; Carusotto, Iacopo

    2017-06-01

    We investigate the helically propagating edge states associated with pseudo-Landau levels in strained honeycomb lattices. We exploit chiral symmetry to derive a general criterion for the existence of these propagating edge states in the presence of only nearest-neighbor hoppings and we verify our criterion using numerical simulations of both uniaxially and trigonally strained honeycomb lattices. We show that the propagation of the helical edge state can be controlled by engineering the shape of the edges. Sensitivity to chiral-symmetry-breaking next-nearest-neighbor hoppings is assessed. Our result opens up an avenue toward the precise control of edge modes through manipulation of the edge shape.

  2. Saddle-node dynamics for edge detection

    SciTech Connect

    Wong, Y.F.

    1994-09-01

    The author demonstrates how the formulation of a nonlinear scale-space filter can be used for edge detection and junction analysis. By casting edge-preserving filtering in terms of maximizing information content subject to an average cost function, the computed cost at each pixel location becomes a local measure of edgeness. This computation depends on a single scale parameter and the given image data. Unlike previous approaches which require careful tuning of the filter kernels for various types of edges, this scheme is general enough to be able to handle different edges, such as lines, step edges, corners and junctions. Anisotropy in the data is handled automatically by the nonlinear dynamics.

  3. Edge Simulation Laboratory Project Report

    SciTech Connect

    Cohen, R. H.; Dorf, M.; Dorr, M.; Rognlien, T. D.

    2011-02-25

    In 2010 The Edge Simulation Laboratory (ESL) embarked upon the plan laid out in the renewal proposal submitted in December 2009. This proposal called for initially parallel efforts addressing the physics of the closed-flux-surface pedestal region, using existing computational tools (GYRO, BOUT++) and analytic modeling, and physics of the scrape-off layer via development of the new edge gyrokinetic code COGENT. Progress in the former area is described in a series of monthly progress reports prepared by General Atomics; these are attached as a set of appendices (describing work done in the month prior to the indicated date). Progress in the latter area, as well as associated theoretical development, is described.

  4. On Edge Exchangeable Random Graphs

    NASA Astrophysics Data System (ADS)

    Janson, Svante

    2017-06-01

    We study a recent model for edge exchangeable random graphs introduced by Crane and Dempsey; in particular we study asymptotic properties of the random simple graph obtained by merging multiple edges. We study a number of examples, and show that the model can produce dense, sparse and extremely sparse random graphs. One example yields a power-law degree distribution. We give some examples where the random graph is dense and converges a.s. in the sense of graph limit theory, but also an example where a.s. every graph limit is the limit of some subsequence. Another example is sparse and yields convergence to a non-integrable generalized graphon defined on (0,∞).

  5. Feature Extraction Without Edge Detection

    DTIC Science & Technology

    1993-09-01

    feature? A.I. Memo 1356, MIT Artificial Intellegence Lab, April 1992. [65] W. A. Richards, B. Dawson, and D. Whittington. Encoding contour shape by...AD-A279 842 . " Technical Report 1434 --Feature Extraction Without Edge Detection Ronald D. Chane MIT Artificial .Intelligencc Laboratory ",, 𔃾•d...Chaney 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER Massachusetts Institute of Technology Artificial

  6. Edge effects and delamination failures

    NASA Technical Reports Server (NTRS)

    Herakovich, C. T.

    1989-01-01

    The fundamental relationship between the morphology of a composite laminate and the resulting free edge effects is explored and related to delamination failures. Cross-ply, angle-ply, and quasi-isotropic laminates are discussed in detail. It is shown that the local mismatch in elastic properties of adjacent layers and the global stacking sequence of a laminate both have a significant influence on the interlaminar stresses and delamination failures.

  7. Retention and the competitive edge.

    PubMed

    Lemery, L D

    2000-01-01

    I believe that retaining effective, seasoned employees enhances an organization's ability to compete in the marketplace. Though these seasoned employees seem to be more explicitly expensive, a detailed analysis of the costs involved in hiring and orienting replacement personnel may prove this assumption false. In addition, seasoned employees' intimate job knowledge actually constitutes the organization's competitive edge. Therefore, retaining seasoned personnel seems to become an important, mission- and vision-imperative institutional objective.

  8. Etching Of Semiconductor Wafer Edges

    DOEpatents

    Kardauskas, Michael J.; Piwczyk, Bernhard P.

    2003-12-09

    A novel method of etching a plurality of semiconductor wafers is provided which comprises assembling said plurality of wafers in a stack, and subjecting said stack of wafers to dry etching using a relatively high density plasma which is produced at atmospheric pressure. The plasma is focused magnetically and said stack is rotated so as to expose successive edge portions of said wafers to said plasma.

  9. Edge Coloring, Polyhedra and Probability

    DTIC Science & Technology

    1998-11-01

    programming relaxation (called the fractional chromatic index). For any graph G one can compute x*(G) in polynomial time but deciding whether x’{G) = A or...has large maximum degree and satisfies two technical conditions, then the equality holds. The constructive proof provides a randomized polynomial ...computes an optimal edge coloring of any graph in polynomial time, on average. Acknowledgements I would like to thank Bruce Reed, Dana Scott, Alan

  10. Topological edge states in pnictides

    NASA Astrophysics Data System (ADS)

    Youmans, Cody; Ghaemi, Pouyan; Kargarian, Mehdi

    In some members of the ferro-pnictides, non-trivial topology in the bulk band-structure is related to potentially observable gapless edge states. We study these states numerically and analytically for a range of parameters, with and without superconductivity and antiferromagnetic SDW ordering, and their relation to the symmetries and topologically non-trivial aspects of our model Hamiltonian. Support was provided by the Doctoral Student Research Grant program at the Graduate Center, CUNY.

  11. A Note on the Total Number of Double Eulerian Circuits in Multigraphs

    NASA Astrophysics Data System (ADS)

    Liskovets, Valery

    2002-12-01

    We formulate explicitly and discuss a simple new enumerative formula for double (directed) eulerian circuits in n-edged labeled multigraphs. The formula follows easily from a recent 2-parametric formula of B. Lass.

  12. Edge-driven microplate kinematics

    USGS Publications Warehouse

    Schouten, Hans; Klitgord, Kim D.; Gallo, David G.

    1993-01-01

    It is known from plate tectonic reconstructions that oceanic microplates undergo rapid rotation about a vertical axis and that the instantaneous rotation axes describing the microplate's motion relative to the bounding major plates are frequently located close to its margins with those plates, close to the tips of propagating rifts. We propose a class of edge-driven block models to illustrate how slip across the microplate margins, block rotation, and propagation of rifting may be related to the relative motion of the plates on either side. An important feature of these edge-driven models is that the instantaneous rotation axes are always located on the margins between block and two bounding plates. According to those models the pseudofaults or traces of disrupted seafloor resulting from the propagation of rifting between microplate and major plates may be used independently to approximately trace the continuous kinematic evolution of the microplate back in time. Pseudofault geometries and matching rotations of the Easter microplate show that for most of its 5 m.y. history, block rotation could be driven by the drag of the Nazca and Pacific plates on the microplate's edges rather than by a shear flow of mantle underneath.

  13. Edge-driven microplate kinematics

    USGS Publications Warehouse

    Schouten, Hans; Klitgord, Kim D.; Gallo, David G.

    1993-01-01

    It is known from plate tectonic reconstructions that oceanic microplates undergo rapid rotation about a vertical axis and that the instantaneous rotation axes describing the microplate's motion relative to the bounding major plates are frequently located close to its margins with those plates, close to the tips of propagating rifts. We propose a class of edge-driven block models to illustrate how slip across the microplate margins, block rotation, and propagation of rifting may be related to the relative motion of the plates on either side. An important feature of these edge-driven models is that the instantaneous rotation axes are always located on the margins between block and two bounding plates. According to those models the pseudofaults or traces of disrupted seafloor resulting from the propagation of rifting between microplate and major plates may be used independently to approximately trace the continuous kinematic evolution of the microplate back in time. Pseudofault geometries and matching rotations of the Easter microplate show that for most of its 5 m.y. history, block rotation could be driven by the drag of the Nazca and Pacific plates on the microplate's edges rather than by a shear flow of mantle underneath.

  14. Swords into Plowshares.

    ERIC Educational Resources Information Center

    Raiche, Annabelle

    1981-01-01

    Describes a course on peace and justice offered by the College of St. Catherine in St. Paul, Minnesota. The course includes religious readings and service in a local justice-related agency or organization. (SJL)

  15. Beating Swords into . . . Chips?

    ERIC Educational Resources Information Center

    Marshall, Eliot

    1991-01-01

    Discussed are the efforts of the Pentagon to help U.S. companies remain competitive in high-tech civilian markets. The tug-of-war for these companies between Congress, which has come to view them as a vehicle for pork-barrel funding, and the administration, which is trying to rein them in, is described. (KR)

  16. A method for computing the leading-edge suction in a higher-order panel method

    NASA Technical Reports Server (NTRS)

    Ehlers, F. E.; Manro, M. E.

    1984-01-01

    Experimental data show that the phenomenon of a separation induced leading edge vortex is influenced by the wing thickness and the shape of the leading edge. Both thickness and leading edge shape (rounded rather than point) delay the formation of a vortex. Existing computer programs used to predict the effect of a leading edge vortex do not include a procedure for determining whether or not a vortex actually exists. Studies under NASA Contract NAS1-15678 have shown that the vortex development can be predicted by using the relationship between the leading edge suction coefficient and the parabolic nose drag. The linear theory FLEXSTAB was used to calculate the leading edge suction coefficient. This report describes the development of a method for calculating leading edge suction using the capabilities of the higher order panel methods (exact boundary conditions). For a two dimensional case, numerical methods were developed using the double strength and downwash distribution along the chord. A Gaussian quadrature formula that directly incorporates the logarithmic singularity in the downwash distribution, at all panel edges, was found to be the best method.

  17. Effects of edge reconstruction on the common groups terminated zigzag phosphorene nanoribbon

    NASA Astrophysics Data System (ADS)

    Xiao, Huaping; Guo, Sumei; Zhang, Chunxiao; He, Chaoyu; Zhong, Jianxin

    2017-05-01

    Edge configuration plays an important role in the electronic properties of nano-structures. In this work, we perform first-principles calculations to study the effects of the cooperation between neighbor groups on the edge configuration and the electronic properties of zigzag-PNRs (ZPNRs) terminated by common groups H, F, O, S and OH. We find that the cooperation has little effect on the H(F)-terminated ZPNRs, but gives rise to an edge reconstruction for the O(S)-terminated ZPNRs. The edge reconstruction derives from the repulsion between neighbor O atoms and the distortion of the P skeleton induced by the p state coupling among the edge, second edge and third edge P atoms. In comparison to the H-terminated ZPNRs, O-terminated ZPNRs are also a semiconductor and enlarge the band gap, but bring about an extra transport channel for the charge transport at the edge and decreases the effective mass of the electron and hole. OH-terminated ZPNRs also undergo a doubling of the unit cell (UC) along the periodic direction because of the different directions of the neighbor O-H bonds. In comparison with the H-terminated ZPNRs, OH-terminated ZPNRs show a similar band gap and electronic effective mass, but increase the effective mass of the hole.

  18. Knife-edge seal for vacuum bagging

    NASA Technical Reports Server (NTRS)

    Rauschl, J. A.

    1980-01-01

    Cam actuated clamps pinch bagging material between long knife edge (mounted to clamps) and high temperature rubber cushion bonded to baseplate. No adhesive, tape, or sealing groove is needed to seal edge of bagging sheet against base plate.

  19. Edge and coupled core/edge transport modeling in tokamak

    SciTech Connect

    Pearlstein, L D; Casper, T A; Cohen, R H; LoDestro, L L; Mattor, N; Porter, G D; Rensink, M E; Rognlien, T D; Ryutov, D D; Scott, H A; Wan, A

    1998-10-14

    Recent advances in the theory and modelling of tokamak edge, scrape-off-layer and divertor plasmas are described. The effects of the poloidal ExB drift on inner/outer divertor-plate asymmetries within a 1D analysis are shown to be in good agreement with experimental observations; above a critical v ExB, the model predicts transitions to supersonic SOL flow at the inboard midplane. Two-dimensional simulations show the importance of ExB flow in the private-flux region and B-drift effects. A theory of rough plasma-facing surfaces is given, and interesting effects, some traveling back up the magnetic field-lines to the SOL plasma, are predicted. The parametric dependence of detached-plasma states in slab geometry has been explored; with sufficient pumping, the location of the ionization front can be controlled; otherwise only fronts at the plate or the X-point are stable. Studies with a more accurate Monte-Carlo neutrals model and a detailed non-LTE radiation-transport code indicate various effects are important for quantitative rnodelling. Long-lived oscillatory UEDGE solutions in both ITER and DIII-D are reported. Detailed simulations of the DIII-D core and edge are presented; impurity and plasma flow are shown to be well modelled with UEDGE, and the roles of impurity and neutral transport in the edge and SOL are discussed.

  20. RECENT EXPERIMENTAL STUDIES OF EDGE AND INTERNAL TRANSPORT BARRIERS IN THE DIII-D TOKAMAK

    SciTech Connect

    P. GOHIL; L.R. BAYLOR; K.H. BURRELL; T.A. CASPER; E.J. DOYLE; C.M. GREENFIELD; T.C. JERNIGAN; J.E. KINSEY; C.J LASNIER; R.A. MOYER; M. MURAKAMI; T.L. RHODES; D.L. RUDAKOV; G.M. STAEBLER; G. WANG; J.G. WATKINS; W.P. WEST; L.ZENG

    2002-08-01

    Results from recent experiments on the DIII-D tokamak have revealed many important details on transport barriers at the plasma edge and in the plasma core. These experiments include: (a) the formation of the H-mode edge barrier directly by pellet injection; (b) the formation of a quiescent H-mode edge barrier (QH-mode) which is free from edge localized modes (ELMs), but which still exhibits good density and radiative power control; (c) the formation of multiple transport barriers, such as the quiescent double barrier (QDB) which combines a internal transport barrier with the quiescent H-mode edge barrier. Results from the pellet-induced H-mode experiments indicate that: (a) the edge temperature (electron or ion) is not a critical parameter for the formation of the H-mode barrier, (b) pellet injection leads to an increased gradient in the radial electric field, E{sub r}, at the plasma edge; (c) the experimentally determined edge parameters at barrier transition are well below the predictions of several theories on the formation of the H-mode barrier, (d) pellet injection can lower the threshold power required to form the H-mode barrier. The quiescent H-mode barrier exhibits good density control as the result of continuous magnetohydrodynamic (MHD) activity at the plasma edge called the edge harmonic oscillation (EHO). The EHO enhances the edge particle transport while maintaining a good energy transport barrier. The ability to produce multiple barriers in the QDB regime has led to long duration, high performance plasmas with {beta}{sub NH{sub 89}} values of 7 for up to 10 times the confinement time. Density profile control in the plasma core of QDB plasmas has been demonstrated using on-axis ECH.

  1. Learning from "Talk-around-the-Edges."

    ERIC Educational Resources Information Center

    Searle, Dennis; Dudley-Marling, Curt

    1995-01-01

    Argues that "talk around the edges," informal exchanges between children in the classroom, are important moments for the enhancement of language facility, at least as important as formal language lessons. Provides approaches to incorporating "talk around the edges" or talk much like "talk around the edges" into lessons. (TB)

  2. Reduction of Free-Edge Stress Concentration

    DTIC Science & Technology

    1985-01-01

    oscillatory type of behavior near the free edge of the capped laminate before converging to zero further inside the laminate. The length of the edge effect is...Condition," J. Comp. Materials. Vol. 14 (1980), p. 2. 13. Altus, E., Rotem, A. and Shmueli, M., "Free Edge Effect in Angle- Ply Laminates - A New

  3. Understanding and preventing the edge effect.

    PubMed

    Cheneau, Edouard; Wolfram, Roswitha; Leborgne, Laurent; Waksman, Ron

    2003-02-01

    Edge stenosis, combining neointimal proliferation and negative remodeling, remains a serious limitation of vascular brachytherapy. This review comprehensively presents terminology, definitions, mechanisms, and treatment strategies to better understand the complexities of edge narrowing. The major contributors to this phenomenon are known; understanding the practical solutions will enable us to further minimize the problem of the edge effect.

  4. Densified edge seals for fuel cell components

    DOEpatents

    DeCasperis, Anthony J.; Roethlein, Richard J.; Breault, Richard D.

    1982-01-01

    A porous fuel cell component, such as an electrode substrate, has a densified edge which forms an improved gas seal during operation when soaked with electrolyte. The edges are made from the same composition as the rest of the component and are made by compressing an increased thickness of this material along the edges during the fabrication process.

  5. K-edge densitometer (KED)

    SciTech Connect

    Sprinkle, J.K.; Hansen, W.J.

    1993-02-11

    In 1979, a K-edge densitometer (KED) was installed by the Safeguards Assay group from Los Alamos National Laboratory in the PNC reprocessing plant at Tokai-mura, Japan. It uses an active nondestructive assay technique, KED, to measure the plutonium concentration of the product solution. The measurement uncertainty of an assay depends on the count time chosen, but can be 0.5% or better. The computer hardware and software were upgraded in 1992. This manual describes the operation of the instrument, with an emphasis on the user interface to the software.

  6. Results from the EDGES Survey

    NASA Astrophysics Data System (ADS)

    van Zee, Liese; EDGES Team

    2017-03-01

    Results are presented from a deep imaging survey with the Spitzer Space Telescope which was designed to identify and measure the faint stellar populations around nearby galaxies. The Extended Disk Galaxy Exploration Science (EDGES) Survey includes a sample of 92 nearby galaxies with a range of morphological types and environments. The observations include a field-of-view of at least 5 times the optical size and are deep enough to detect stellar mass surface densities of several hundredths of a solar mass per square parsec. The observations reveal extended stellar features, such as stellar disks and stellar streams, around many of the target galaxies, as expected from hierarchical galaxy formation scenarios.

  7. Continuum Gyrokinetic Edge New Technology

    SciTech Connect

    Dorr, M. R.; Hittinger, J. A.; Dorf, M.; Cohen, R.; Ghosh, D.; Lee, W.; Reynolds, C.

    2016-05-02

    COGENT is a simulation code that models the plasma evolution in the edge region of a tokamak fusion reactor, from the open field line scrape-off layer, across the separatrix, and into the core. The model is based on the 4D gyrokinetic closure of the kinetic equations for a plasma coupled to an electrostatic potential field. The background magnetic field is prescribed either analytically or generated from experimental data, and the grid is aligned with magnetic flux surfaces. Multiple collision operator options are provided, from Krook to fully nonlinear Fokker-Planck.

  8. Fractal-based image edge detection

    NASA Astrophysics Data System (ADS)

    Luo, Huiguo; Zhu, Yaoting; Zhu, Guang-Xi; Wan, Faguang; Zhang, Ping

    1993-08-01

    Image edge is an important feature of image. Usually, we use Laplacian or Sober operator to get an image edge. In this paper, we use fractal method to get the edge. After introducing Fractal Brownian Random (FBR) field, we give the definition of Discrete Fractal Brownian Increase Random (DFBIR) field and discuss its properties, then we apply the DFBIR field to detect the edge of an image. According to the parameters H and D of DFBIR, we give a measure M equals (alpha) H + (beta) D. From the M value of each pixel, we can detect the edge of image.

  9. Environmental Dataset Gateway (EDG) Search Widget

    EPA Pesticide Factsheets

    Use the Environmental Dataset Gateway (EDG) to find and access EPA's environmental resources. Many options are available for easily reusing EDG content in other other applications. This allows individuals to provide direct access to EPA's metadata outside the EDG interface. The EDG Search Widget makes it possible to search the EDG from another web page or application. The search widget can be included on your website by simply inserting one or two lines of code. Users can type a search term or lucene search query in the search field and retrieve a pop-up list of records that match that search.

  10. Environmental Dataset Gateway (EDG) REST Interface

    EPA Pesticide Factsheets

    Use the Environmental Dataset Gateway (EDG) to find and access EPA's environmental resources. Many options are available for easily reusing EDG content in other other applications. This allows individuals to provide direct access to EPA's metadata outside the EDG interface. The EDG REST Interface allows each users to query the catalog through a URL using REST syntax. Accessing individual metadata documents through their REST URLs, or groups of documents that match specific search criteria through a REST-formatted search URL, provides powerful functionality for searching, viewing, and sharing EDG records.

  11. Chiral edge fluctuations of colloidal membranes

    NASA Astrophysics Data System (ADS)

    Jia, Leroy L.; Zakhary, Mark J.; Dogic, Zvonimir; Pelcovits, Robert A.; Powers, Thomas R.

    2017-06-01

    We study edge fluctuations of a flat colloidal membrane comprised of a monolayer of aligned filamentous viruses. Experiments reveal that a peak in the spectrum of the in-plane edge fluctuations arises for sufficiently strong virus chirality. Accounting for internal liquid crystalline degrees of freedom by the length, curvature, and geodesic torsion of the edge, we calculate the spectrum of the edge fluctuations. The theory quantitatively describes the experimental data, demonstrating that chirality couples in-plane and out-of-plane edge fluctuations to produce the peak.

  12. Double Compton scatter telescope calibration

    NASA Technical Reports Server (NTRS)

    Dayton, B.; Simone, J.; Green, M.; Long, J.; Zanrosso, E.; Zych, A. D.; White, R. S.

    1981-01-01

    Calibration techniques for a medium energy gamma ray telescope are described. Gain calibration using Compton edge spectra involves comparisons of pulse height spectra with spectra simulated by a Monte Carlo computer code which includes Compton scattering and pair production, plural scattering and variable energy resolution, and cell size. The telescope considered comprises 56 cells of liquid scintillator in four size groups, with a total liquid volume of 325 l; each cell has its own photomultiplier tube. Energy and angular resolutions and the PMT gain calibration procedure are verified with double scatter data for monoenergetic gamma rays at a known location. Detection probabilities for any cell combination in the two telescope arrays are calculated per steradian as a function of the scattering for a number of different energies with a Van de Graaff accelerator.

  13. Double Compton scatter telescope calibration

    NASA Technical Reports Server (NTRS)

    Dayton, B.; Simone, J.; Green, M.; Long, J.; Zanrosso, E.; Zych, A. D.; White, R. S.

    1981-01-01

    Calibration techniques for a medium energy gamma ray telescope are described. Gain calibration using Compton edge spectra involves comparisons of pulse height spectra with spectra simulated by a Monte Carlo computer code which includes Compton scattering and pair production, plural scattering and variable energy resolution, and cell size. The telescope considered comprises 56 cells of liquid scintillator in four size groups, with a total liquid volume of 325 l; each cell has its own photomultiplier tube. Energy and angular resolutions and the PMT gain calibration procedure are verified with double scatter data for monoenergetic gamma rays at a known location. Detection probabilities for any cell combination in the two telescope arrays are calculated per steradian as a function of the scattering for a number of different energies with a Van de Graaff accelerator.

  14. Stent edge dissection: depth of injury and adverse outcome.

    PubMed

    Goldstein, James A

    2015-08-01

    Deep stent edge dissection by OCT predicts adverse outcome. STEMI culprit lesions are most susceptible to edge dissection. Procedural performance influences edge dissection. © 2015 Wiley Periodicals, Inc.

  15. Evaluating Edge Detection through Boundary Detection

    NASA Astrophysics Data System (ADS)

    Wang, Song; Ge, Feng; Liu, Tiecheng

    2006-12-01

    Edge detection has been widely used in computer vision and image processing. However, the performance evaluation of the edge-detection results is still a challenging problem. A major dilemma in edge-detection evaluation is the difficulty to balance the objectivity and generality: a general-purpose edge-detection evaluation independent of specific applications is usually not well defined, while an evaluation on a specific application has weak generality. Aiming at addressing this dilemma, this paper presents new evaluation methodology and a framework in which edge detection is evaluated through boundary detection, that is, the likelihood of retrieving the full object boundaries from this edge-detection output. Such a likelihood, we believe, reflects the performance of edge detection in many applications since boundary detection is the direct and natural goal of edge detection. In this framework, we use the newly developed ratio-contour algorithm to group the detected edges into closed boundaries. We also collect a large data set ([InlineEquation not available: see fulltext.]) of real images with unambiguous ground-truth boundaries for evaluation. Five edge detectors (Sobel, LoG, Canny, Rothwell, and Edison) are evaluated in this paper and we find that the current edge-detection performance still has scope for improvement by choosing appropriate detectors and detector parameters.

  16. Optimal edge filters explain human blur detection.

    PubMed

    McIlhagga, William H; May, Keith A

    2012-09-14

    Edges are important visual features, providing many cues to the three-dimensional structure of the world. One of these cues is edge blur. Sharp edges tend to be caused by object boundaries, while blurred edges indicate shadows, surface curvature, or defocus due to relative depth. Edge blur also drives accommodation and may be implicated in the correct development of the eye's optical power. Here we use classification image techniques to reveal the mechanisms underlying blur detection in human vision. Observers were shown a sharp and a blurred edge in white noise and had to identify the blurred edge. The resultant smoothed classification image derived from these experiments was similar to a derivative of a Gaussian filter. We also fitted a number of edge detection models (MIRAGE, N(1), and N(3)(+)) and the ideal observer to observer responses, but none performed as well as the classification image. However, observer responses were well fitted by a recently developed optimal edge detector model, coupled with a Bayesian prior on the expected blurs in the stimulus. This model outperformed the classification image when performance was measured by the Akaike Information Criterion. This result strongly suggests that humans use optimal edge detection filters to detect edges and encode their blur.

  17. Edge states in the transition to turbulence in pipe and other shear flows

    NASA Astrophysics Data System (ADS)

    Eckhardt, Bruno; Skufca, Joseph D.; Yorke, James A.

    2005-11-01

    We study the boundary of the laminar region in pipe and other shear flows near the onset of turbulence. Approaching the boundary from the laminar side, the lifetime of perturbations increases, and it diverges when the boundary is reached. Once this critical amplitude is exceeded the trajectory swings up to the turbulent regime, but its lifetime varies sensitively with amplitude, consistent with the strange saddle picture of the turbulence proposed earlier. The edge trajectory is asymptotic to a single well defined state, independent of the type of perturbation. The edge then becomes the stable manifold of this structure. In the case of a model shear flow, the edge states are simple or period doubled or chaotic trajectories. The case of pipe flow shows less variability and the edge state seems to remain close to a state with simple vortex structure.

  18. Measuring edge importance to improve immunization performance

    NASA Astrophysics Data System (ADS)

    Huang, He; Yan, Zhijun; Pan, Yaohui

    2014-12-01

    The edge heterogeneity has a remarkable influence on disease spreading, but it has seldom been considered in the disease-controlling policies. Based on the gravity model, we propose the edge importance index to describe the influence of edge heterogeneity on immunization strategies. Then the edge importance and contact weight are combined to calculate the infection rates on the I-S (Infected-Susceptible) edges in the complex network, and the difference of the infection rates on strong and weak ties is analyzed. Simulation results show that edge heterogeneity has a significant influence on the performance of immunization strategies, and better immunization efficiency is derived when the vaccination rate of the nodes in the weak I-S edges is increased.

  19. Haptic Edge Detection Through Shear

    NASA Astrophysics Data System (ADS)

    Platkiewicz, Jonathan; Lipson, Hod; Hayward, Vincent

    2016-03-01

    Most tactile sensors are based on the assumption that touch depends on measuring pressure. However, the pressure distribution at the surface of a tactile sensor cannot be acquired directly and must be inferred from the deformation field induced by the touched object in the sensor medium. Currently, there is no consensus as to which components of strain are most informative for tactile sensing. Here, we propose that shape-related tactile information is more suitably recovered from shear strain than normal strain. Based on a contact mechanics analysis, we demonstrate that the elastic behavior of a haptic probe provides a robust edge detection mechanism when shear strain is sensed. We used a jamming-based robot gripper as a tactile sensor to empirically validate that shear strain processing gives accurate edge information that is invariant to changes in pressure, as predicted by the contact mechanics study. This result has implications for the design of effective tactile sensors as well as for the understanding of the early somatosensory processing in mammals.

  20. Haptic Edge Detection Through Shear

    PubMed Central

    Platkiewicz, Jonathan; Lipson, Hod; Hayward, Vincent

    2016-01-01

    Most tactile sensors are based on the assumption that touch depends on measuring pressure. However, the pressure distribution at the surface of a tactile sensor cannot be acquired directly and must be inferred from the deformation field induced by the touched object in the sensor medium. Currently, there is no consensus as to which components of strain are most informative for tactile sensing. Here, we propose that shape-related tactile information is more suitably recovered from shear strain than normal strain. Based on a contact mechanics analysis, we demonstrate that the elastic behavior of a haptic probe provides a robust edge detection mechanism when shear strain is sensed. We used a jamming-based robot gripper as a tactile sensor to empirically validate that shear strain processing gives accurate edge information that is invariant to changes in pressure, as predicted by the contact mechanics study. This result has implications for the design of effective tactile sensors as well as for the understanding of the early somatosensory processing in mammals. PMID:27009331

  1. Reflections on the Knife Edge

    PubMed Central

    Murphy, John Patrick Michael

    2011-01-01

    Introduction The accompanying article, written by John Murphy, a retired lawyer and lifelong outdoorsman from his beloved Colorado Rockies, draws the striking parallel between his experiences as a mountain climber and as a patient with metastatic melanoma facing the hope and uncertainty of experimental therapy. Both are life-threatening circumstances, demanding courage and hope, and challenging our soul in a way almost unique to human experience. Both involve a conscious choice to move forward into dangerous and uncertain territory, and require a determination to look death (John's “Reaper”) in the eye. Many remarkable books and films have been written about such experiences. I recall in particular the 2003 documentary film Touching the Void, about the incredible survival of a mountaineer who returned from a perilous fall in Peru. I highly recommend it to the reader. Another is Laura Hillenbrand's Unbroken: A World War II Story of Survival, Resilience, and Redemption (Random House, 2010), about the survival of a prisoner of war, the celebrated miler Louis Zamperini. Again, unbridled courage and undeniable hope turned futility into future. John Murphy's reflections remind us of the daily heroism of our patients who are holding tight to the lifeline offered by clinical research. Good climbing, John. All of us are with you on that Knife Edge, waiting for our turn to ascend... and hoping to be as courageous as you were then on Capitol Peak and are again now on the Knife Edge of a clinical trial. For our turn will come. PMID:21349953

  2. Spectral red edge parameters for winter wheat under different nitrogen support levels

    NASA Astrophysics Data System (ADS)

    Cheng, Yisong; Hu, Chunsheng; Dai, Hui; Lei, Yuping

    2005-09-01

    Hyperspectral remote sensing is not only an important technical method in observing global ecosystems and vegetation cover change, but also a main aspect of studies on precision agriculture. In order to monitor crop nutrient supply condition and to realize precision fertilization, spectral red edge parameter for winter wheat was studied. Experiments were carried out through 8 years since 1997 under four nitrogen support levels in Luancheng Station, Hebei province (e.g., 0, 100, 200 and 300 kg N ha-1). Canopy reflectance spectrum was measured by ASD HandHeld Spectroradiometer (325-1075 nm) during 2002 and 2004. The dynamics of red edge parameters for physiological stages of winter wheat canopy were calculated using first derivative curve. Analyses revealed that the red edge of the wheat canopy reflectance spectrum locates between 720-740 nm. All the different trial had distinct "red shift" trait, but higher N stress had shorter "red edge" wavelength. Position of red edge turned "blue shift" after pregnant period. Red edge swing is a first-order derivative spectrum when wavelength reached red edge position, red edge swing double peak shape showed that the pregnant period was the best stage to detect nitrogen deficiency. Red edge swing correlated with relative chlorophyll content and leaf N content. Area of red edge peak is the value of first-order derivative spectra accumulative total between 680 and 750 nm. These parameters can be used to estimate LAI and N accumulating quantities, and these results provide information needed for the development of variable-rate N application technology.

  3. On the edge energy of lipid membranes and the thermodynamic stability of pores

    SciTech Connect

    Pera, H.; Kleijn, J. M.; Leermakers, F. A. M.

    2015-01-21

    To perform its barrier function, the lipid bilayer membrane requires a robust resistance against pore formation. Using a self-consistent field (SCF) theory and a molecularly detailed model for membranes composed of charged or zwitterionic lipids, it is possible to predict structural, mechanical, and thermodynamical parameters for relevant lipid bilayer membranes. We argue that the edge energy in membranes is a function of the spontaneous lipid monolayer curvature, the mean bending modulus, and the membrane thickness. An analytical Helfrich-like model suggests that most bilayers should have a positive edge energy. This means that there is a natural resistance against pore formation. Edge energies evaluated explicitly in a two-gradient SCF model are consistent with this. Remarkably, the edge energy can become negative for phosphatidylglycerol (e.g., dioleoylphosphoglycerol) bilayers at a sufficiently low ionic strength. Such bilayers become unstable against the formation of pores or the formation of lipid disks. In the weakly curved limit, we study the curvature dependence of the edge energy and evaluate the preferred edge curvature and the edge bending modulus. The latter is always positive, and the former increases with increasing ionic strength. These results point to a small window of ionic strengths for which stable pores can form as too low ionic strengths give rise to lipid disks. Higher order curvature terms are necessary to accurately predict relevant pore sizes in bilayers. The electric double layer overlap across a small pore widens the window of ionic strengths for which pores are stable.

  4. A double-double/double-single computation package

    SciTech Connect

    Bailey, David H.

    2004-12-01

    The DDFUNIDSFUN software permits a new or existing Fortran-90 program to utilize double-double precision (approx. 31 digits) or double-single precision (approx. 14 digits) arithmetic. Double-double precision is required by a rapidly expandirtg body of scientific computations in physics and mathematics, for which the conventional 64-bit IEEE computer arithmetic (about 16 decimal digit accuracy) is not sufficient. Double-single precision permits users of systems that do not have hardware 64-bit IEEE arithmetic (such as some game systems) to perform arithmetic at a precision nearly as high as that of systems that do. Both packages run significantly faster Than using multiple precision or arbitrary precision software for this purpose. The package includes an extensive set of low-level routines to perform high-precision arithmetic, including routines to calculate various algebraic and transcendental functions, such as square roots, sin, ccc, exp, log and others. In addition, the package includes high-level translation facilities, so that Fortran programs can utilize these facilities by making only a few changes to conventional Fortran programs. In most cases, the only changes that are required are to change the type statements of variables that one wishes to be treated as multiple precision, plus a few other minor changes. The DDFUN package is similar in functionality to the double-double part of the GD package, which was previously written at LBNL. However, the DDFUN package is written exclusively in Fortran-90, thus avoidIng difficulties that some users experience when using GD, which includes both Fortran-90 and C++ code.

  5. The reconstructed edges of the hexagonal BN.

    PubMed

    Zhao, Ruiqi; Gao, Junfeng; Liu, Zhongfan; Ding, Feng

    2015-06-07

    As an important two-dimensional material which shows exceptional mechanical and chemical stability, superior electronic properties, along with broad applications, the hexagonal-BN (h-BN) has drawn great attention recently. Here we report a systematic study on the structural stability, electronic and magnetic properties of various h-BN edges, including both bare and hydrogen-terminated ones. It is found that along the armchair (AC) direction, the pristine edge is the most stable one because of the formation of a triple B≡N bond, while, along the zigzag (ZZ) directions, the reconstructed ones, ZZB + N and ZZN57 are more stable. The pristine edges are more stable in bare BN in most cases if saturated with hydrogen. By applying the theory of Wulff construction, we predicted that an unpassivated BN domain prefers the hexagonal shape enclosed with bare AC edges i.e., AC-Ns, AC, AC-Bs if the feedstock varies from N-rich to B-rich. However, the evolution from ZZN edged triangular domain, to hexagonal domain enclosed with AC edges, and ZZB edged triangle may occur if the edges are terminated by hydrogen atoms. Further calculation shows that these edges present rich type-dependent properties and thus are important for various applications. This theoretical study showed that controlling the morphologies of BN domains and BN edges is crucial for various applications.

  6. Edge detection in microscopy images using curvelets

    PubMed Central

    Gebäck, Tobias; Koumoutsakos, Petros

    2009-01-01

    Background Despite significant progress in imaging technologies, the efficient detection of edges and elongated features in images of intracellular and multicellular structures acquired using light or electron microscopy is a challenging and time consuming task in many laboratories. Results We present a novel method, based on the discrete curvelet transform, to extract a directional field from the image that indicates the location and direction of the edges. This directional field is then processed using the non-maximal suppression and thresholding steps of the Canny algorithm to trace along the edges and mark them. Optionally, the edges may then be extended along the directions given by the curvelets to provide a more connected edge map. We compare our scheme to the Canny edge detector and an edge detector based on Gabor filters, and show that our scheme performs better in detecting larger, elongated structures possibly composed of several step or ridge edges. Conclusion The proposed curvelet based edge detection is a novel and competitive approach for imaging problems. We expect that the methodology and the accompanying software will facilitate and improve edge detection in images available using light or electron microscopy. PMID:19257905

  7. Polarity control of h-BN nanoribbon edges by strain and edge termination.

    PubMed

    Yamanaka, Ayaka; Okada, Susumu

    2017-03-29

    We studied the polarity of h-BN nano-flakes in terms of their edge geometries, edge hydrogen termination, and uniaxial strain by evaluating their electrostatic potential using density functional theory. Our calculations have shown that the polarity of the nanoribbons is sensitive to their edge shape, edge termination, and uniaxial tensile strain. Polarity inversion of the ribbons can be induced by controlling the hydrogen concentration at the edges and the uniaxial tensile strain. The polarity inversion indicates that h-BN nanoribbons can exhibit non-polar properties at a particular edge hydrogen concentration and tensile strain, even though the nanoribbons essentially have polarity at the edge. We also found that the edge angle affects the polarity of nanoribbons with hydrogenated edges.

  8. [A double gallbladder].

    PubMed

    Mink van der Molen, A B; Salu, M K

    1991-04-06

    A 59-year-old woman is described with symptomatic cholelithiasis. A double gallbladder was incidentally found during abdominal surgery. The literature on a double gallbladder is reviewed with respect to incidence, anatomy, diagnosis and therapy.

  9. Chromosome doubling method

    DOEpatents

    Kato, Akio

    2006-11-14

    The invention provides methods for chromosome doubling in plants. The technique overcomes the low yields of doubled progeny associated with the use of prior techniques for doubling chromosomes in plants such as grasses. The technique can be used in large scale applications and has been demonstrated to be highly effective in maize. Following treatment in accordance with the invention, plants remain amenable to self fertilization, thereby allowing the efficient isolation of doubled progeny plants.

  10. The double identity of linguistic doubling.

    PubMed

    Berent, Iris; Bat-El, Outi; Brentari, Diane; Dupuis, Amanda; Vaknin-Nusbaum, Vered

    2016-11-29

    Does knowledge of language consist of abstract principles, or is it fully embodied in the sensorimotor system? To address this question, we investigate the double identity of doubling (e.g., slaflaf, or generally, XX; where X stands for a phonological constituent). Across languages, doubling is known to elicit conflicting preferences at different levels of linguistic analysis (phonology vs. morphology). Here, we show that these preferences are active in the brains of individual speakers, and they are demonstrably distinct from sensorimotor pressures. We first demonstrate that doubling in novel English words elicits divergent percepts: Viewed as meaningless (phonological) forms, doubling is disliked (e.g., slaflaf < slafmak), but once doubling in form is systematically linked to meaning (e.g., slaf = ball, slaflaf = balls), the doubling aversion shifts into a reliable (morphological) preference. We next show that sign-naive speakers spontaneously project these principles to novel signs in American Sign Language, and their capacity to do so depends on the structure of their spoken language (English vs. Hebrew). These results demonstrate that linguistic preferences doubly dissociate from sensorimotor demands: A single stimulus can elicit diverse percepts, yet these percepts are invariant across stimulus modality--for speech and signs. These conclusions are in line with the possibility that some linguistic principles are abstract, and they apply broadly across language modality.

  11. Magnetohydrodynamic stability of tokamak edge plasmas

    SciTech Connect

    Connor, J.W.; Hastie, R.J.; Wilson, H.R.; Miller, R.L.

    1998-07-01

    A new formalism for analyzing the magnetohydrodynamic stability of a limiter tokamak edge plasma is developed. Two radially localized, high toroidal mode number n instabilities are studied in detail: a peeling mode and an edge ballooning mode. The peeling mode, driven by edge current density and stabilized by edge pressure gradient, has features which are consistent with several properties of tokamak behavior in the high confinement {open_quotes}H{close_quotes}-mode of operation, and edge localized modes (or ELMs) in particular. The edge ballooning mode, driven by the pressure gradient, is identified; this penetrates {approximately}n{sup 1/3} rational surfaces into the plasma (rather than {approximately}n{sup 1/2}, expected from conventional ballooning mode theory). Furthermore, there exists a coupling between these two modes and this coupling provides a picture of the ELM cycle.

  12. Coulomb edge effects in graphene nanoribbons

    NASA Astrophysics Data System (ADS)

    Jaskolski, W.; Ayuela, A.

    2014-10-01

    Coulomb effects in graphene nanoribbons with arbitrary edges are investigated with the use of a mean-field Hubbard model. It was recently shown that chiral ribbons with minimal edges, characterized by the translation vector (n,m), have a similar structure of bands localized around the Fermi energy as pure zigzag ribbons (n-m,0). Here we show that these flat bands in both ribbon cases differ in detail due to the perturbation induced by armchair edge nodes. For chiral ribbons the edge bands split at the zone boundary, where the corresponding bands of (n-m,0) zigzag ribbons are degenerate. Coulomb interactions enhance strongly this splitting and at the same time they bring spin into play. We modify each edge keeping global sublattice balance to find that spin degeneracy can be partially lifted. The breaking of spin-degeneracy depends on the asymmetry between the edges and in some cases leads to spin-polarized currents.

  13. Age and growth of the sword razor clam Ensis arcuatus in the Ría de Pontevedra (NW Spain): Influence of environmental parameters

    NASA Astrophysics Data System (ADS)

    Hernández-Otero, A.; Gaspar, M. B.; Macho, G.; Vázquez, E.

    2014-01-01

    The sword razor clam Ensis arcuatus is the most important commercial species of razor clam in Spain, and its fishery in the Ría de Pontevedra (Galicia, NW Spain) is the most productive. Despite the economic importance of this species, information on its biology is scarce. This study reports shell morphometric relationships, age, and growth rates of E. arcuatus in three fishing beds in the Ría de Pontevedra (Brensa, Bueu and Ons, located in respectively the inner, middle and outer zones of the ria), providing the first estimates of growth parameters for the species in the Iberian Peninsula. Growth was estimated by examination of surface growth rings and internal shell microgrowth patterns (acetate peel technique) that proved to be the most suitable method for growth estimate. Growth of E. arcuatus was slower in Bueu (L∞ = 140.4, k = 0.40) followed by Brensa (L∞ = 151.91, k = 0.40) and Ons (L∞ = 172.7, k = 0.33), and the clams reached commercial size in 1.7, 2.3 and 2.8 years in Ons, Brensa and Bueu, respectively. The differences in growth between sites in relation to environmental parameters are evaluated and the implications for the razor clam fishery are discussed.

  14. Operation Dominic, Shot Sword Fish. Project Officer's report - Project 1. 3b. Effects of an underwater nuclear explosion on hydroacoustic systems

    SciTech Connect

    McMillan, T.; La Houssaye, W.P.; Johnson, C.T.

    1985-09-01

    The objectives of Project 1.2 were to determine and evaluate the effects of an underwater nuclear explosion on the operational capabilities of shipboard sonar and other types of hydroacoustic systems. Project 1.3b included all measurements at ranges greater than 10 nautical miles and the results of these measurements constitute the subject of this report. This report concerns the effects of the underwater nuclear explosion, Sword Fish, on: (a) Long-range active detection systems at the first convergence zone (25 to 30 miles); (b) Passive shipboard or submarine sonars at a few hundred miles; and (c) Long-range passive detection and surveillance at Sound Surveillance System (SOSUS) and Missile Impact Locating System (MILS) stations at several hundred to several thousand miles. A submarine station at the first convergence zone and five shipboard stations at ranges from 200 miles to 5,000 miles recorded signals from hydrophones suspended at various depths to approximately 2,000 feet. Submarines on other assignments recorded signals on standard submarine sonar equipment on a not-to interfere basis. SOSUS and MILS stations operated normally during the period and also made special magnetic-tape and strip-chart recordings of signals from single hydrophones from before burst time to several hours after burst.

  15. [Artificial crowns influence upon edge parodontium status].

    PubMed

    Zhulev, E N; Serov, A B

    2010-01-01

    With the aim of prosthetic treatment efficacy increase study of edge parodontium tissue reaction upon different types of artificial crowns was done and methods of chronic localized parodontitis prevention were developed. Changes of the main gingival fluid characteristics (amount, acidity, interleukine-1beta concentration) and indicators of microcirculation in edge parodontium of the teeth under the artificial crowns influence were disclosed. There were developed methods of chronic localized parodontitis prevention produced by artificial crowns edge.

  16. Electron acceleration in stochastic double layers

    NASA Technical Reports Server (NTRS)

    Lotko, William

    1987-01-01

    Transversely localized double layers evolve randomly in turbulent regions of strongly magnetized plasma carrying current along the magnetic field. Results from numerical simulations and spacecraft observations in the auroral plasma indicate that the parallel electric field in such regions is microscopically intermittent or stochastic. The implications of stochastic double layer fields on electron acceleration will be discussed in terms of a statistical process involving ensemble averages over test particle motion. A Fokker-Planck equation can be derived for the electron phase space density, which depends on the mean and rms amplitudes of the double layers, the mean double layer density, and the initial electron velocity distribution. It is shown that the resulting electron acceleration is very sensitive to the ratio of the initial electron energy to the rms double layer amplitude. When this ratio is large, the acceleration process differs little from that expected in a dc electric field. When it is small, stochastic heating competes with directed acceleration. Evidence for both cases can be found in the auroral ionosphere in association with so-called inverted-V precipitation and collimated edge precipitation.

  17. An edge index for topological insulators

    NASA Astrophysics Data System (ADS)

    Prodan, Emil

    2009-03-01

    Topological insulators display dissipationless currents flowing at the edges of the samples. These currents are associated to chiral edge modes, whose existence is intrinsically linked to the topology of the electronic states of the bulk. The edge modes can be easily investigated when the edges are smooth and have a periodicity, but as soon as the periodicity is absent, the problem becomes un-traceable by purely theoretical means. In my talk I will exemplify the use of non-commutative calculus to explore the properties, especially the stability of the edge modes. For example, using such techniques one can give a fairly elementary proof that the edge modes in Chern insulators survive even for a rough (random) edge. Similarly, for the Spin-Hall effect, one can define an observable and its associated current whose conductance remains quantized during various deformations of the Hamiltonian system. It turns out that in all cases, the edge conductance is given by the index of a Fredholm operator, which provides a new topological invariant linked directly to the edge rather than the bulk.

  18. Topological edge states of bound photon pairs

    NASA Astrophysics Data System (ADS)

    Gorlach, Maxim A.; Poddubny, Alexander N.

    2017-05-01

    We predict the existence of interaction-driven edge states of bound two-photon quasiparticles in a dimer periodic array of nonlinear optical cavities. The energy spectrum of photon pairs is dramatically richer than in the noninteracting case or in a simple lattice, featuring collapse and revival of multiple edge and bulk modes as well as edge states in continuum. We link the edge-state existence to the two-photon quantum walk graph connectivity. Our results offer a route to control quantum entanglement and provide insights into the physics of many-body topological states.

  19. Moveable Leading Edge Device for a Wing

    NASA Technical Reports Server (NTRS)

    Pitt, Dale M. (Inventor); Eckstein, Nicholas Stephen (Inventor)

    2013-01-01

    A method and apparatus for managing a flight control surface system. A leading edge section on a wing of an aircraft is extended into a deployed position. A deformable section connects the leading edge section to a trailing section. The deformable section changes from a deformed shape to an original shape when the leading edge section is moved into the deployed position. The leading edge section on the wing is moved from the deployed position to an undeployed position. The deformable section changes to the deformed shape inside of the wing.

  20. Study on edge extracting in noise image

    NASA Astrophysics Data System (ADS)

    Feng, Gui; Lin, Qiwei; Fu, QingQing

    2008-03-01

    In order to reduce the influence of noise on edge extracting and improve the precision of edge localization on the image, after analyzed the principle, strong points and short points of some traditional edge detecting methods, an effective algorithm for edge extracting in noise image was proposed in this paper. Adopting thought of traditional multi-directional and multistage combinational filtering, an image detail-preserving adaptive filter is designed to remove noise, and then extract the edge in the image. On the basis of the classical Sobel operator, we introduced an algorithm with resisting noise, good real-time and locating accurate edge. The algorithm can distinguish real edge from noise in terms of the theory of successive and smooth edge and random noise. The algorithm was accomplished under visual C++ 6.0 environment and tested by several standard images. The experimental result prove that the presented method is feasible and effective when the salt-pepper pollution of image is smaller than 15%, furthermore the method can extract edges with high location precision and good continuity accurately and effectively, at the same time, it has high processing speed.

  1. Modelling of edge localised modes and edge localised mode control

    SciTech Connect

    Huijsmans, G. T. A.; Loarte, A.; Chang, C. S.; Ferraro, N.; Sugiyama, L.; Waelbroeck, F.; Xu, X. Q.; Futatani, S.

    2015-02-15

    Edge Localised Modes (ELMs) in ITER Q = 10 H-mode plasmas are likely to lead to large transient heat loads to the divertor. To avoid an ELM induced reduction of the divertor lifetime, the large ELM energy losses need to be controlled. In ITER, ELM control is foreseen using magnetic field perturbations created by in-vessel coils and the injection of small D2 pellets. ITER plasmas are characterised by low collisionality at a high density (high fraction of the Greenwald density limit). These parameters cannot simultaneously be achieved in current experiments. Therefore, the extrapolation of the ELM properties and the requirements for ELM control in ITER relies on the development of validated physics models and numerical simulations. In this paper, we describe the modelling of ELMs and ELM control methods in ITER. The aim of this paper is not a complete review on the subject of ELM and ELM control modelling but rather to describe the current status and discuss open issues.

  2. Edge mode spectroscopy and imaging for film edge properties in magnetic nanostructures

    NASA Astrophysics Data System (ADS)

    McMichael, Robert

    2014-03-01

    Lithography is an act of violence. Often, films are almost entirely obliterated by patterning, leaving only nanostructures behind with film edges that have borne the brunt of the damage, edges that carry with them the scars of energetic ion bombardment, reactive ions, liftoff and exposure to ambient conditions. In this talk, I will present a variation on ferromagnetic resonance force microscopy that can provide insight into the magnetic properties of film edges in magnetic nanostructures. The method relies on the non-uniformity of the magnetic field in patterned-film nanostructures that are magnetized in-plane, specifically, the low-field regions that form near where the magnetization is directed normal to the edge. In these regions, localized precession forms as trapped spin wave modes, and the resonance condition of these modes serves as an indicator of the edge properties. I will present modeling and measurements on a 500 nm diameter, 25 nm thick Permalloy disk to illustrate the method. Micromagnetic modeling of this disk predicts a main mode that is nearly uniform across the sample and three localized edge modes with higher resonance fields. The spectra measured with various tip positions and mode imaging are consistent with the modeling results. In addition to a strong center mode, three distinct edge modes are observed when the tip is near the disk edge. For a symmetric disk, the modeling predicts that the edge mode resonances are identical on the two opposite edges. However, the measured edge mode resonances on opposite edges of the disk are detected at different resonance fields, suggesting inhomogeneity of the edge properties. By rotating the applied field, we control the position of the localized edge mode along the edge of the disk and confirm that the edge mode resonance field has a strong angular dependence, showing that edge mode properties can vary significantly in a nominally circular disk.

  3. Efficient edge-guided full-waveform inversion by Canny edge detection and bilateral filtering algorithms

    NASA Astrophysics Data System (ADS)

    Xiang, Shiming; Zhang, Haijiang

    2016-11-01

    It is known full-waveform inversion (FWI) is generally ill-conditioned and various strategies including pre-conditioning and regularizing the inversion system have been proposed to obtain a reliable estimation of the velocity model. Here, we propose a new edge-guided strategy for FWI in frequency domain to efficiently and reliably estimate velocity models with structures of the size similar to the seismic wavelength. The edges of the velocity model at the current iteration are first detected by the Canny edge detection algorithm that is widely used in image processing. Then, the detected edges are used for guiding the calculation of FWI gradient as well as enforcing edge-preserving total variation (TV) regularization for next iteration of FWI. Bilateral filtering is further applied to remove noise but keep edges of the FWI gradient. The proposed edge-guided FWI in the frequency domain with edge-guided TV regularization and bilateral filtering is designed to preserve model edges that are recovered from previous iterations as well as from lower frequency waveforms when FWI is conducted from lower to higher frequencies. The new FWI method is validated using the complex Marmousi model that contains several steeply dipping fault zones and hundreds of horizons. Compared to FWI without edge guidance, our proposed edge-guided FWI recovers velocity model anomalies and edges much better. Unlike previous image-guided FWI or edge-guided TV regularization strategies, our method does not require migrating seismic data, thus is more efficient for real applications.

  4. Topological edge states and fractional quantum Hall effect from umklapp scattering.

    PubMed

    Klinovaja, Jelena; Loss, Daniel

    2013-11-08

    We study anisotropic lattice strips in the presence of a magnetic field in the quantum Hall effect regime. At specific magnetic fields, causing resonant umklapp scattering, the system is gapped in the bulk and supports chiral edge states in close analogy to topological insulators. In electron gases with stripes, these gaps result in plateaus for the Hall conductivity exactly at the known fillings n/m (both positive integers and m odd) for the integer and fractional quantum Hall effect. For double strips, we find topological phase transitions with phases that support midgap edge states with flat dispersion. The topological effects predicted here could be tested directly in optical lattices.

  5. Summary of Section Data on Trailing-Edge High-Lift Devices

    NASA Technical Reports Server (NTRS)

    1948-01-01

    A summary has been made of available data on the characteristics of airfoil sections with trailing-edge high-lift devices. Data for plain, split, and slotted flaps are collected and analyzed. The effects of each of the variables involved in the design of the various types of flap are examined and, in cases where sufficient data are given, optimum configurations are deduced. Wherever possible, the effects of airfoil section, Reynolds number, and leading-edge roughness are shown. For single and double slotted flaps, where a great mass of unrelated date are available, maximum lift coefficients of a large number of configurations are presented in tables.

  6. Excitonic localization at macrostep edges in AlGaN/AlGaN multiple quantum wells

    NASA Astrophysics Data System (ADS)

    Hou, Mengjun; Qin, Zhixin; Zhang, Lisheng; Han, Tianyang; Wang, Mingxing; Xu, Fujun; Wang, Xinqiang; Yu, Tongjun; Fang, Zheyu; Shen, Bo

    2017-04-01

    Double peaks at wavelength of 276 and 290 nm are observed for AlGaN/AlGaN multiple quantum wells (MQWs). Cathodoluminescence (CL) mappings identify that the emission at 290 nm originates from the macrostep edges. Potential minima induced by local variation of QW thickness and Ga incorporation are found along the step edges, where quantum wires (QWRs) are formed. The lateral advance rate of macrostep (∼310 nm/h) is obtained by investigating the distribution of QWRs. Temperature-dependent CL spectrum suggest that thermal quenching for 290 nm emission is dramatically suppressed compared with that for conventional QWs emission, which shows excitonic localization characteristics of QWRs.

  7. Fog Inputs and Edge Effects From Canopy to Soil in a California Redwood Forest

    NASA Astrophysics Data System (ADS)

    Ewing, H. A.; Weathers, K. C.; Elliott, A.

    2005-12-01

    As a horizontally-driven vector, fog interacts with the structure of the landscape to create spatial patterns of deposition not seen in the more even distribution of vertically-delivered rainwater inputs. In coastal CA, fog arrives during the summer growing season when trees are most physiologically active and rainfall is negligible, thus it may be an ecologically significant source of water and nutrients. We are examining the interaction of horizontal and vertical inputs with forest structure, and the influence of these inputs on plant physiology, ecosystem fluxes, and soil characteristics in coastal redwood forests, Sonoma, CA. Fog water flux to the forest floor via throughfall (TF) was approximately 5 times greater at the windward (ocean-facing) edge than at sites on the interior of the patch, while rain delivery was more even across the whole forest patch. This edge effect for TF showed an exponential decline away from the windward forest edge; all sites greater than about 75 m from the edge received comparable fog inputs. Soil moisture patterns reflected the input pattern: the surface soil horizon at the windward edge had consistently greater water content than did interior sites throughout the fog season. After a large fog event, throughfall added to edge soils roughly doubled the moisture content at the soil surface. The absence of such input in the forest interior left relative water content lower by a factor of two to three compared to the edge site. While both tension and gravity lysimeters collected water at all sites in the forest during the rainy season, only tension lysimeters near the windward forest edge collected water in the fog season. These results suggest water availability at edge and interior locations can differ markedly during the fog water season and that fog may affect rates of primary production, biogeochemical cycling, and soil development.

  8. Saturn's Rings Edge-on

    NASA Technical Reports Server (NTRS)

    1995-01-01

    In one of nature's most dramatic examples of 'now-you see-them, now-you-don't', NASA's Hubble Space Telescope captured Saturn on May 22, 1995 as the planet's magnificent ring system turned edge-on. This ring-plane crossing occurs approximately every 15 years when the Earth passes through Saturn's ring plane.

    For comparison, the top picture was taken by Hubble on December 1, 1994 and shows the rings in a more familiar configuration for Earth observers.

    The bottom picture was taken shortly before the ring plane crossing. The rings do not disappear completely because the edge of the rings reflects sunlight. The dark band across the middle of Saturn is the shadow of the rings cast on the planet (the Sun is almost 3 degrees above the ring plane.) The bright stripe directly above the ring shadow is caused by sunlight reflected off the rings onto Saturn's atmosphere. Two of Saturn's icy moons are visible as tiny starlike objects in or near the ring plane. They are, from left to right, Tethys (slightly above the ring plane) and Dione.

    This observation will be used to determine the time of ring-plane crossing and the thickness of the main rings and to search for as yet undiscovered satellites. Knowledge of the exact time of ring-plane crossing will lead to an improved determination of the rate at which Saturn 'wobbles' about its axis (polar precession).

    Both pictures were taken with Hubble's Wide Field Planetary Camera 2. The top image was taken in visible light. Saturn's disk appears different in the bottom image because a narrowband filter (which only lets through light that is not absorbed by methane gas in Saturn's atmosphere) was used to reduce the bright glare of the planet. Though Saturn is approximately 900 million miles away, Hubble can see details as small as 450 miles across.

    The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Spaced Flight Center for NASA's Office of Space Science

  9. A Mesh Refinement Study on the Impact Response of a Shuttle Leading-Edge Panel Finite Element Simulation

    NASA Technical Reports Server (NTRS)

    Fasanella, Edwin L.; Jackson, Karen E.; Lyle, Karen H.; Spellman, Regina L.

    2006-01-01

    A study was performed to examine the influence of varying mesh density on an LS-DYNA simulation of a rectangular-shaped foam projectile impacting the space shuttle leading edge Panel 6. The shuttle leading-edge panels are fabricated of reinforced carbon-carbon (RCC) material. During the study, nine cases were executed with all possible combinations of coarse, baseline, and fine meshes of the foam and panel. For each simulation, the same material properties and impact conditions were specified and only the mesh density was varied. In the baseline model, the shell elements representing the RCC panel are approximately 0.2-in. on edge, whereas the foam elements are about 0.5-in. on edge. The element nominal edge-length for the baseline panel was halved to create a fine panel (0.1-in. edge length) mesh and doubled to create a coarse panel (0.4-in. edge length) mesh. In addition, the element nominal edge-length of the baseline foam projectile was halved (0.25-in. edge length) to create a fine foam mesh and doubled (1.0-in. edge length) to create a coarse foam mesh. The initial impact velocity of the foam was 775 ft/s. The simulations were executed in LS-DYNA for 6 ms of simulation time. Contour plots of resultant panel displacement and effective stress in the foam were compared at four discrete time intervals. Also, time-history responses of internal and kinetic energy of the panel, kinetic and hourglass energy of the foam, and resultant contact force were plotted to determine the influence of mesh density.

  10. Comparing object recognition from binary and bipolar edge features

    PubMed Central

    Jung, Jae-Hyun; Pu, Tian; Peli, Eli

    2017-01-01

    Edges derived from abrupt luminance changes in images carry essential information for object recognition. Typical binary edge images (black edges on white background or white edges on black background) have been used to represent features (edges and cusps) in scenes. However, the polarity of cusps and edges may contain important depth information (depth from shading) which is lost in the binary edge representation. This depth information may be restored, to some degree, using bipolar edges. We compared recognition rates of 16 binary edge images, or bipolar features, by 26 subjects. Object recognition rates were higher with bipolar edges and the improvement was significant in scenes with complex backgrounds.

  11. Gyrokinetic Models for Edge Plasmas*

    NASA Astrophysics Data System (ADS)

    Dimits, Andris

    2010-11-01

    The use of gyrokinetic equations for the simulation of magnetic fusion edge and scrapeoff-layer plasmas requires that the equations be valid for large relative perturbation amplitudes and, possibly, large flows. The Hamiltonian gyrokinetic theory has therefore been extended to two new orderings [1,2] that are more general than the standard ones in that they allow for potential perturbations or ExB flows of order the thermal levels. These theories both generalize and show that additional terms should have been present some related prior work. Here, full (low-β) electromagnetic toroidal equation sets are presented, and he energy conservation relations are derived using Noether's theorem in a Lagrangian variational approach. Useful subsidiary and reduced orderings are also considered that result in considerable simplification, and methods for the numerical implementation of the new terms in the equations will also be discussed. *This work was performed for US DOE by LLNL under Contract DE-AC52-07NA27344 and is part of the ESL. [4pt] [1] A.M. Dimits et al., Phys. Fluids B4, 274 (1992). [0pt] [2] A.M. Dimits, Phys. Plasmas 17, 055901 (2010).

  12. Beyond the Kuiper Belt Edge

    NASA Astrophysics Data System (ADS)

    Sheppard, Scott

    2011-01-01

    Of the thousands of known objects beyond Neptune, only one has a perihelion significantly beyond 50 AU, Sedna at 75 AU. Kuiper Belt surveys to date have not been optimized to survey beyond the Kuiper Belt edge at 50 AU. Most of these surveys either did not go faint enough, did not have the required long cadence to detect very slow moving objects or covered too small of an area of sky. The dynamical and physical properties of objects in this region offer key constraints on the formation and evolution of our solar system. In order to probe the Sedna like population of objects with moderate radii (100 km) we propose a deep wide-field outer solar system survey. This survey will allow us to determine if the objects beyond 50 AU are fainter than expected, if there is truly a dearth of objects, or if the Kuiper Belt continues again after some sizable gap possibly caused by a planet sized object. We will be able to examine the origin of Sedna and determine if this eccentric, distant body is unique (as once believed for Pluto) or just the first of a new class of object in the outer Solar System. We will also explore the Neptune Trojans and scattered disk populations through the survey.

  13. Structure at the Leading Edge

    NASA Astrophysics Data System (ADS)

    Quint, D. A.; Schwarz, J. M.; Marchetti, M. C.

    2009-03-01

    The leading edge of a crawling cell is propelled forward by a polymerizing network of branched actin filaments. This emergent structural array seems to be rigid enough to support and push against the cell membrane within the appropriate time scales under which cell motility can be realized. We seek to understand how such a network can optimize its structure to generate the rigidity required, particularly focusing on the role of branching in the network. For isolated elastic beams, which model semiflexible polymers, the critical buckling load is enhanced when branched supports are included. Therefore, we conjecture that an optimal branching angle is found by looking at the competition between branching providing collective structural support, which results in polymerization with a component perpendicular to the direction of motion, and polymerization along the direction of motion. To partially test this conjecture, we simulate a directed, branched network in the absence of forces. Preliminary results indicate a lower bound on the optimal branching angle of approximately 40 degrees (to be compared with the observed 70 degree branching angle). Studies of a directed, branched network with forces will also be addressed.

  14. On the Edge of Mercury

    NASA Image and Video Library

    2017-09-28

    In this image, Mercury's horizon cuts a striking edge against the stark blackness of space. On the right, sunlight harshly brings the landscape into relief while on the left, the surface is shrouded in the darkness of night. This image was acquired as part of MDIS's limb imaging campaign. Once per week, MDIS captures images of Mercury's limb, with an emphasis on imaging the southern hemisphere limb. These limb images provide information about Mercury's shape and complement measurements of topography made by the Mercury Laser Altimeter (MLA) of Mercury's northern hemisphere. The MESSENGER spacecraft is the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments and radio science investigation are unraveling the history and evolution of the Solar System's innermost planet. In the mission's more than three years of orbital operations, MESSENGER has acquired over 250,000 images and extensive other data sets. MESSENGER is capable of continuing orbital operations until early 2015. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  15. Beyond the Kuiper Belt Edge

    NASA Astrophysics Data System (ADS)

    Sheppard, Scott; Trujillo, Chad

    2012-02-01

    Of the thousands of known objects beyond Neptune, only one has a perihelion significantly beyond 50 AU, Sedna at 75 AU. Kuiper Belt surveys to date have not been optimized to survey beyond the Kuiper Belt edge at 50 AU. Most of these surveys either did not go faint enough, did not have the required long cadence to detect very slow moving objects or covered too small of an area of sky. The dynamical and physical properties of objects in this region offer key constraints on the formation and evolution of our solar system. In order to probe the Sedna like population of objects with moderate radii (100 km) we propose a medium wide-field outer solar system survey. This survey will allow us to determine if the objects beyond 50 AU are fainter than expected, if there is truly a dearth of objects, or if the Kuiper Belt continues again after some sizable gap possibly caused by a planet sized object. We will be able to examine the origin of Sedna and determine if this eccentric, distant body is unique (as once believed for Pluto) or just the first of a new class of object in the outer Solar System.

  16. Beyond the Kuiper Belt Edge

    NASA Astrophysics Data System (ADS)

    Sheppard, Scott

    2012-06-01

    Of the thousands of known objects beyond Neptune, only one has a perihelion significantly beyond 50 AU, Sedna at 75 AU. Kuiper Belt surveys to date have not been optimized to survey beyond the Kuiper Belt edge at 50 AU. Most of these surveys either did not go faint enough, did not have the required long cadence to detect very slow moving objects or covered too small of an area of sky. The dynamical and physical properties of objects in this region offer key constraints on the formation and evolution of our solar system. In order to probe the Sedna like population of objects with moderate radii (100 km) we propose a deep wide-field outer solar system survey. This survey will allow us to determine if the objects beyond 50 AU are fainter than expected, if there is truly a dearth of objects, or if the Kuiper Belt continues again after some sizable gap possibly caused by a planet sized object. We will be able to examine the origin of Sedna and determine if this eccentric, distant body is unique (as once believed for Pluto) or just the first of a new class of object in the outer Solar System. We will also explore the Neptune Trojans and scattered disk populations through the survey.

  17. Leading edge gypsy moth population dynamics

    Treesearch

    M. R. Carter; F. W. Ravlin; M. L. McManus

    1991-01-01

    Leading edge gypsy moth populations have been the focus of several intervention programs (MDIPM, AIPM). Knowledge of gypsy moth population dynamics in leading edge area is crucial for effective management. Populations in these areas tend to reach outbreak levels (noticeable defoliation) within three to four years after egg masses are first detected. Pheromone traps...

  18. Eliminating Unbonded Edges In Explosive Bonding

    NASA Technical Reports Server (NTRS)

    Bement, Laurence J.; Kushnick, Anne C.

    1991-01-01

    Explosive-bonding technique elminates sharp unbonded notch normally occurring between flyer plate and baseplate. Makes it possible to simply break away unbonded outer extremity of flyer plate; no longer necessary to grind away unbonded edge to prevent collection of corrosive contaminants in edge voids. Method not limited to flat surfaces.

  19. Annotated Bibliography of EDGE2D Use

    SciTech Connect

    J.D. Strachan and G. Corrigan

    2005-06-24

    This annotated bibliography is intended to help EDGE2D users, and particularly new users, find existing published literature that has used EDGE2D. Our idea is that a person can find existing studies which may relate to his intended use, as well as gain ideas about other possible applications by scanning the attached tables.

  20. How Forest Inhomogeneities Affect the Edge Flow

    NASA Astrophysics Data System (ADS)

    Boudreault, Louis-Étienne; Dupont, Sylvain; Bechmann, Andreas; Dellwik, Ebba

    2017-03-01

    Most of our knowledge on forest-edge flows comes from numerical and wind-tunnel experiments where canopies are horizontally homogeneous. To investigate the impact of tree-scale heterogeneities ({>}1 m) on the edge-flow dynamics, the flow in an inhomogeneous forest edge on Falster island in Denmark is investigated using large-eddy simulation. The three-dimensional forest structure is prescribed in the model using high resolution helicopter-based lidar scans. After evaluating the simulation against wind measurements upwind and downwind of the forest leading edge, the flow dynamics are compared between the scanned forest and an equivalent homogeneous forest. The simulations reveal that forest inhomogeneities facilitate flow penetration into the canopy from the edge, inducing important dispersive fluxes in the edge region as a consequence of the flow spatial variability. Further downstream from the edge, the forest inhomogeneities accentuate the canopy-top turbulence and the skewness of the wind-velocity components while the momentum flux remains unchanged. This leads to a lower efficiency in the turbulent transport of momentum within the canopy. Dispersive fluxes are only significant in the upper canopy. Above the canopy, the mean flow is less affected by the forest inhomogeneities. The inhomogeneities induce an increase in the mean wind speed that was found to be equivalent to a decrease in the aerodynamic height of the canopy. Overall, these results highlight the importance of forest inhomogeneities when looking at canopy-atmosphere exchanges in forest-edge regions.