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Sample records for massive paradoxical air

  1. [Paradoxical air embolism resulted in acute myocardial infarction and massive ischemic brain injury in a patient operated on in a sitting position].

    PubMed

    Anan'ev, E P; Polupan, A A; Savin, I A; Goryachev, A S; Troitskiy, A P; Kolokol'nikov, A E; Kulikovskiy, V P; Matskovskiy, I V; Abramov, T A; Podlepich, V V; Krylov, K Yu; Sychev, A A; Tabasaranskiy, T F; Pashin, A A; Lubnin, A Yu

    2016-01-01

    Paradoxical air embolism (PAE) is a rare life-threatening complication when air emboli enter arteries of the systemic circulation and cause their occlusion. Here, we describe a clinical case of PAE developed during neurosurgery in a patient in the sitting position. PAE led to injuries to the cerebral blood vessels, coronary arteries, and lungs, which caused death of the patient. An effective measure for preventing PAE is abandoning surgery in the sitting position in favor of surgery in the prone position.

  2. Paradoxes

    ERIC Educational Resources Information Center

    Partis, M.

    1972-01-01

    Examples of logical paradoxes, including the square root of two paradox, Achilles and the tortoise paradox, author paradox, Russell paradox, bibliomaniac paradox, and Berry paradox, are presented; some are resolved. (DT)

  3. Paradoxical Personality and Academic Achievement in College Students From Buenos Aires

    PubMed Central

    Freiberg Hoffmann, Agustín; Fernández Liporace, María Mercedes

    2015-01-01

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

  4. Paradoxical Personality and Academic Achievement in College Students From Buenos Aires.

    PubMed

    Freiberg Hoffmann, Agustín; Fernández Liporace, María Mercedes

    2015-11-01

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

  5. Management of traumatic pneumothorax with massive air leakage: role of a bronchial blocker: a case report

    PubMed Central

    Lee, Dong Kyu; Lim, Sang Ho; Lim, Byung Gun; Kang, Sung Wook

    2014-01-01

    Massive air leakage through a lacerated lung produces inadequate ventilation and hypoxemia. Tube exchange from a single to double lumen endotracheal tube (DLT), and lung separation to maintain oxygenation, are challenging for seriously injured patients. In this case report, we aim to describe how a bronchial blocker (BB) makes it easier to perform a lung separation in this situation; it also increases the overall safety of the procedure. A 35-year-old female (163 cm, 47 kg) suffered from blunt chest trauma due to a traffic accident; the accident caused right-sided lung laceration with massive air leakage. Paradoxically, positive ventilation worsened SaO2 and leakage increased through a chest tube. We introduced BB while the patient was still awake: Left-side one-lung ventilation (OLV) was established and anesthesia was induced. After PaO2 was maximized with OLV, we changed the endotracheal tube to DLT without a hypoxic event. By BB placement, we maintained PaO2 at a secure level, conducted mechanical ventilation and exchanged the tube without deterioration. PMID:25473467

  6. The Diesel Paradox: Why Dieselization Will Lead to Cleaner Air

    SciTech Connect

    Eberhardt, James J.

    2000-08-20

    There are challenges facing the U.S. and the world that are brought on by the growing demand for transporting people and goods. These include the growing consumption of petroleum, urban air pollution, and global climate change.

  7. Massive air embolism from continuous venovenous haemofiltration causing electromechanical dissociation in a cardiac surgical patient.

    PubMed

    Ku, Lisa; Weinberg, Laurence; Seevanayagam, Siven; Baldwin, Ian; Opdam, Helen; Doolan, Laurie

    2012-06-01

    Venous air embolism is a rare but life-threatening complication of continuous venovenous haemofiltration. We report a case of massive venous air embolism associated with haemofiltration in a 75-year-old man after complicated cardiac surgery. Haemofiltration circuitry and air detector alarms are not infallible and air embolism should be considered in patients receiving such therapy who develop cardiopulmonary instability. We discuss our early intervention, which focused on restoration of the circulation, prevention of further air entry, retrieval of air and supportive care. The use of transoesophageal echocardiography for diagnosis of air embolism and to aid the insertion of a pulmonary artery catheter for air aspiration was essential for management.

  8. Anorexia nervosa with massive pulmonary air leak and extraordinary propagation.

    PubMed

    Jensen, V M; Støving, R K; Andersen, P E

    2017-02-07

    A rare case combining pneumothorax, pneumomediastinum, pneumopericardium, pneumoperitoneum, pneumorrhachis, air in retroperitoneum and extensive subcutaneous emphysema simultaneously in a severely anorectic male with BMI 9.2 (22.8 kg) and multiple vomitings is presented. This unusual condition was treated successfully with conservative medical approach in a specialized somatic unit for anorexia nervosa.

  9. Paradoxical Thromboembolism/ST-Elevation Myocardial Infarction via a Patent Foramen Ovale in Sub-Massive Pulmonary Embolism Following an Upper Extremity Deep Venous Thrombosis: Is It Time for a Change in the Standard of Care?

    PubMed Central

    Tukaye, Deepali Nivas; Cavallazzi, Rodrigo Silva

    2014-01-01

    The objective of this case study is to discuss a rare case of proven paradoxical thromboembolism captured in-transit. A 23-year-old female with a diagnosis of right internal jugular deep vein thrombus who developed acute onset chest pain, dyspnea and hypotension, was selected for the study. Sub-massive PE and STEMI were diagnosed. Transthoracic echocardiogram revealed a left ventricular (LV) mass moving across the aortic valve. Soon after, the patient developed numbness of right extremities with non-palpable pulses. A transesophageal echocardiogram revealed absent LV mass, PFO, left atrial mass entering through the PFO and emboli in bilateral pulmonary arteries. We report a case of sub-massive PE and paradoxical proven coronary and upper extremity embolism, captured in-transit, following destabilization of an UEDVT in a patient with PFO.

  10. Paradoxical Air Microembolism Induces Cerebral Bioelectrical Abnormalities and Occasionally Headache in Patent Foramen Ovale Patients With Migraine

    PubMed Central

    Sevgi, Eser Başak; Erdener, Sefik Evren; Demirci, Mehmet; Topcuoglu, Mehmet Akif; Dalkara, Turgay

    2012-01-01

    Background Although controversial, paradoxical embolism via patent foramen ovale (PFO) may account for some of the migraine attacks in a subset of migraine with aura (MA) patients. Induction of MA attacks with air bubble injection during transcranial Doppler ultrasound in MA patients with PFO supports this view. It is likely that cerebral embolism in patients with right-to-left shunt induces bioelectrical abnormalities to initiate MA under some conditions. Methods and Results We investigated changes in cerebral bioelectrical activity after intravenous microbubble injection in 10 MA patients with large PFO and right-to-left cardiac shunt. Eight PFO patients without migraine but with large right-to-left shunt and 12 MA patients without PFO served as controls. Four MA patients with PFO were reexamined with sham injections of saline without microbubbles. Bioelectrical activity was evaluated using spectral electroencephalography and, passage of microbubbles through cerebral arteries was monitored with transcranial Doppler ultrasound. Microbubble embolism caused significant electroencephalographic power increase in MA+PFO patients but not in control groups including the sham-injected MA+PFO patients. Headache developed in 2 MA with PFO patients after microbubble injection. Conclusions These findings demonstrate that air microembolism through large PFOs may cause cerebral bioelectrical disturbances and, occasionally, headache in MA patients, which may reflect an increased reactivity of their brain to transient subclinical hypoxia–ischemia, and suggest that paradoxical embolism is not a common cause of migraine but may induce headache in the presence of a large PFO and facilitating conditions. PMID:23316313

  11. Convective Lofting Links Indian Ocean Air Pollution to Paradoxical South Atlantic Ozone Maxima

    NASA Technical Reports Server (NTRS)

    Chatfield, Robert B.; Guan, Hong; Thompson, Anne M.; Witte, Jacquelyn C.

    2003-01-01

    We describe a broad resolution of the "Atlantic Paradox" concerning the seasonal and geographic distribution of tropical tropospheric ozone. We describe periods of significant maximum tropospheric O3 for Jan.-April, 1999, exploiting satellite estimates and SHADOZ (Southern Hemisphere Additional Ozonesondes). Trajectory analyses connecting sondes and Total Tropospheric Ozone (TTO)O3 maps suggest a complex influence from the Indian Ocean: beginning with mixed combustion sources, then low level transport, cumulonimbus venting, and finally high-level transport to the west, with possible mixing over Africa. For the Jan.- March highest column-O3 periods in the Atlantic, distinct sounding peaks trace to specific NO sources, especially lightning, while in the same episodes, recurring every 30 or 60 days, more diffuse buildups of Indian-to-Atlantic pollution make important contributions.

  12. Paradoxical cerebral air embolism causing large vessel occlusion treated with endovascular aspiration.

    PubMed

    Belton, Patrick J; Nanda, Ashish; Alqadri, Syeda L; Khakh, Gurpreet S; Chandrasekaran, Premkumar Nattanmai; Newey, Christopher; Humphries, William E

    2017-04-01

    Cerebral air embolism is a dreaded complication of invasive medical procedures. The mainstay of therapy for patients with cerebral air embolism has been hyperbaric oxygen therapy, high flow oxygen therapy, and anticonvulsants. We present a novel therapeutic approach for treatment of cerebral air embolism causing large vessel occlusion, using endovascular aspiration. Our patient developed a cerebral air embolism following sclerotherapy for varicose veins. This caused near total occlusion of the superior division of the M2 segment of the right middle cerebral artery. Symptoms included unilateral paralysis, unintelligible speech, and hemianopia; National Institutes of Health Stroke Scale (NIHSS) on presentation was 16. The air embolism was treated using a distal aspiration technique. Angiography following aspiration showed Thrombolysis in Cerebral Infarction 2B reperfusion. Following aspiration, the patient was re-examined; NIHSS at that time was 4. At 1 month follow-up, the modified Rankin Scale score was 1 and NIHSS was 1. Treatment of cerebral air embolism is discussed.

  13. Paramagnetism Paradoxes: Projectable Demonstrations

    ERIC Educational Resources Information Center

    Sauls, Frederick C.; Vitz, Ed

    2008-01-01

    Drops of oil in Mn(SO[subscript 4])(aq) and drops of the solution in oil show opposite effects when brought near a rare earth magnet. Oxygen, nitrogen, and air bubbles atop water show expected attraction, repulsion, and null behavior, respectively. Air bubbles atop aqueous Mn(SO[subscript 4]) show paradoxical behavior because the magnet's…

  14. Hydrogen peroxide in exhaled air: a source of error, a paradox and its resolution

    PubMed Central

    Peters, Stefan; Kronseder, Angelika; Karrasch, Stefan; Neff, Petra A.; Haaks, Matz; Koczulla, Andreas R.; Reinhold, Petra; Nowak, Dennis

    2016-01-01

    The concentration of hydrogen peroxide (H2O2) in exhaled air has been reported to be elevated in asthma and chronic obstructive pulmonary disease (COPD), but results are inconsistent and difficult to reproduce. As H2O2 occurs in ambient air, we examined its association with exhaled H2O2 in human subjects. Exhaled breath condensate (EBC) of 12 COPD patients and nine healthy control subjects was collected either with an inhalation filter (efficiency 81%) or without. Ambient air condensate (AAC) was collected in parallel and samples were analysed for H2O2. Additionally, ambient H2O2 was recorded by an atmospheric measuring device (online fluorometric measurement). H2O2 concentration in AAC was significantly higher (p<0.001) than in EBC. AAC variations were concordant with the data from the atmospheric measuring instrument. In both subjects' groups, the inhalation filter reduced H2O2 values (p<0.01). Despite generally low levels in exhaled air, analysis by a mathematical model revealed a contribution from endogenous H2O2 production. The low H2O2 levels in exhaled air are explained by the reconditioning of H2O2-containing inhaled air in the airways. Inhaled H2O2 may be one factor in the heterogeneity and limited reproducibility of study results. A valid determination of endogenous H2O2 production requires inhalation filters. PMID:27730191

  15. Hydrogen peroxide in exhaled air: a source of error, a paradox and its resolution.

    PubMed

    Peters, Stefan; Kronseder, Angelika; Karrasch, Stefan; Neff, Petra A; Haaks, Matz; Koczulla, Andreas R; Reinhold, Petra; Nowak, Dennis; Jörres, Rudolf A

    2016-04-01

    The concentration of hydrogen peroxide (H2O2) in exhaled air has been reported to be elevated in asthma and chronic obstructive pulmonary disease (COPD), but results are inconsistent and difficult to reproduce. As H2O2 occurs in ambient air, we examined its association with exhaled H2O2 in human subjects. Exhaled breath condensate (EBC) of 12 COPD patients and nine healthy control subjects was collected either with an inhalation filter (efficiency 81%) or without. Ambient air condensate (AAC) was collected in parallel and samples were analysed for H2O2. Additionally, ambient H2O2 was recorded by an atmospheric measuring device (online fluorometric measurement). H2O2 concentration in AAC was significantly higher (p<0.001) than in EBC. AAC variations were concordant with the data from the atmospheric measuring instrument. In both subjects' groups, the inhalation filter reduced H2O2 values (p<0.01). Despite generally low levels in exhaled air, analysis by a mathematical model revealed a contribution from endogenous H2O2 production. The low H2O2 levels in exhaled air are explained by the reconditioning of H2O2-containing inhaled air in the airways. Inhaled H2O2 may be one factor in the heterogeneity and limited reproducibility of study results. A valid determination of endogenous H2O2 production requires inhalation filters.

  16. Galileo's Paradox

    NASA Astrophysics Data System (ADS)

    Greenslade, Thomas B.

    2008-05-01

    The paradox is a wonderful teaching tool. The sleepy student in the back row is surprised and wakes up, and the student with the instantly memorized answer is forced into the analytical mode. The diagram in Fig. 1 has the following paradox: A body sliding freely down a chord from the edge of the circle reaches the lowest point on the circle at the same time as a body released simultaneously from the top. This result was first mentioned in a 1602 letter from Galileo Galilei to Guidobaldo dal Monte.

  17. [Obesity paradox].

    PubMed

    Aursulesei, Viviana; Cozma, A; Datcu, M D

    2009-01-01

    Obesity has reached global epidemic proportions and is associated with major cardiovascular diseases and reduced overall survival. This paper reviews the metabolic and vascular consequences of dysfunctional adipocytokines in obesity as well as the pathological effects on blood pressure, cardiovascular structure and function. Despite this adverse association, numerous studies have documented an obesity paradox in which overweight and obese population with established cardiovascular disease have a better prognosis. There are potential explanations offered by literature for these puzzling data. For obese hypertensive patients the paradox is possibly linked to the lower systemic vascular resistance and plasma renin activity. In heart failure the excess body weight may confer some protective effects on mortality, due to a more metabolic reserve, higher levels of arterial pressure compatible with higher doses of cardioprotective medications, and a specific neuroendocrine profile with lower levels of circulating natriuretic atrial peptides, attenuated sympathetic nervous system and renin-angiotensin responses. For coronary heart disease and peripheral arterial disease the mechanisms are still uncertain. There are discussed a lesser severity of coronary lesions and left ventricular dysfunction, or a reduced prevalence of moderate-severe chronic obstructive pulmonary disease in patients selected for surgery. On the other hand, the constellation of data which supports purposeful weight reduction in the prevention and treatment of cardiovascular diseases, induces a controversial position regarding this new concept.

  18. Pulmonary embolism and concomitant paradoxical embolism. A case report.

    PubMed

    Abad-Arranz, María; Jara-Palomares, Luis; Martos-Maine, José Luis; Carrasco-Hernandez, Laura; Ortega-Ruiz, Francisco; Otero-Candelera, Remedios

    2014-03-01

    Although patent foramen ovale is a relatively common disease, the presence of paradoxical embolism is a rare clinical condition, representing less than 2% of arterial ischemias. We report the case of a 55-year-old male diagnosed with massive pulmonary embolism and paradoxical embolism in the right arm, secondary to patent foramen ovale. We also highlight some uncertainties in the diagnosis and treatment of patients with paradoxical embolism.

  19. Massive systemic air embolism during off-pump coronary artery surgery.

    PubMed

    Kuralay, Erkan

    2009-01-01

    In OPCAB (off-pump coronary artery bypass) operations, development of cardiac arrest during the distal anastomosis to obtuse marginal coronary artery leads to significantly low blood pressure in the ascending aorta. Therefore, blowing of compressed air in high flow on not-slinged coronary artery may cause air mobilization from the coronary artery system into the ascending aorta that may result in severe brain damage.

  20. A paradox for air pollution controlling in China revealed by “APEC Blue” and “Parade Blue”

    NASA Astrophysics Data System (ADS)

    Liu, Haoran; Liu, Cheng; Xie, Zhouqing; Li, Ying; Huang, Xin; Wang, Shanshan; Xu, Jin; Xie, Pinhua

    2016-09-01

    A series of strict emission control measures were implemented in Beijing and surrounding regions to ensure good air quality during the 2014 Asia-Pacific Economic Cooperation (APEC) summit and 2015 Grand Military Parade (Parade), which led to blue sky days during these two events commonly referred to as “APEC Blue” and “Parade Blue”. Here we calculated Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) and Ozone Monitoring Instrument (OMI) NO2 and HCHO results based on well known DOAS trace gas fitting algorithm and WRF-Chem model (with measured climatology parameter and newest emission inventor) simulated trace gases profiles. We found the NO2 columns abruptly decreased both Parade (43%) and APEC (21%) compared with the periods before these two events. The back-trajectory cluster analysis and the potential source contribution function (PSCF) proved regional transport from southern peripheral cities plays a key role in pollutants observed at Beijing. The diminishing transport contribution from southern air mass during Parade manifests the real effect of emission control measures on NO2 pollution. Based on the ratios of HCHO over NO2 we found there were not only limited the NO2 pollutant but also suppress the O3 contaminant during Parade, while O3 increased during the APEC.

  1. Influence of air pollutants on allergic sensitization: the paradox of increased allergies and decreased resistance to infection.

    PubMed

    Gilmour, M Ian

    2012-01-01

    Air pollution has long been associated with health risks such as increased susceptibility to respiratory infections and potentiation of asthmatic-type responses. Experimental evidence in rodents indicates that air pollutants including diesel exhaust particles (DEPs), gases, and metals cause lung injury, inflammation, reduce aspects of host defense, and may potentiate allergic airway responses. Here we present evidence that diesel exhaust particles delivered by inhalation or aspiration can exacerbate allergic lung disease depending on the material's chemical properties. Genomic analysis of mouse lungs following instillation or inhalation of DEPs shows an alteration spectrum of pathways associated with immune signaling, cell metabolism, and oxidative stress. Diesel exposure also may worsen respiratory infections through depression of protective immune responses. Here we show that mice exposed to diesel and co-infected with influenza had increased influenza virus titers as well as higher levels of lung injury and inflammation in association with increased Th2 cytokines, and a concomitant decrease in Th1 polarization. A simplified model explains how the potentiation of the Th2 arm of immunity by diesel exhaust results in increased allergic sensitization, whereas cell-mediated (protective) immunity against viral infections is simultaneously reduced.

  2. A paradox for air pollution controlling in China revealed by “APEC Blue” and “Parade Blue”

    PubMed Central

    Liu, Haoran; Liu, Cheng; Xie, Zhouqing; Li, Ying; Huang, Xin; Wang, Shanshan; Xu, Jin; Xie, Pinhua

    2016-01-01

    A series of strict emission control measures were implemented in Beijing and surrounding regions to ensure good air quality during the 2014 Asia-Pacific Economic Cooperation (APEC) summit and 2015 Grand Military Parade (Parade), which led to blue sky days during these two events commonly referred to as “APEC Blue” and “Parade Blue”. Here we calculated Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) and Ozone Monitoring Instrument (OMI) NO2 and HCHO results based on well known DOAS trace gas fitting algorithm and WRF-Chem model (with measured climatology parameter and newest emission inventor) simulated trace gases profiles. We found the NO2 columns abruptly decreased both Parade (43%) and APEC (21%) compared with the periods before these two events. The back-trajectory cluster analysis and the potential source contribution function (PSCF) proved regional transport from southern peripheral cities plays a key role in pollutants observed at Beijing. The diminishing transport contribution from southern air mass during Parade manifests the real effect of emission control measures on NO2 pollution. Based on the ratios of HCHO over NO2 we found there were not only limited the NO2 pollutant but also suppress the O3 contaminant during Parade, while O3 increased during the APEC. PMID:27680499

  3. Beyond Parrondo's Paradox

    PubMed Central

    SHU, Jian-Jun; WANG, Qi-Wen

    2014-01-01

    The Parrondo's paradox is a counterintuitive phenomenon where individually-losing strategies can be combined in producing a winning expectation. In this paper, the issues surrounding the Parrondo's paradox are investigated. The focus is lying on testifying whether the same paradoxical effect can be reproduced by using a simple capital dependent game. The paradoxical effect generated by the Parrondo's paradox can be explained by placing all the parameters in one probability space. Based on this framework, it is able to generate other possible paradoxical effects by manipulating the parameters in the probability space. PMID:24577586

  4. [Massive cerebral air embolism following endoscopic retrograde cholangiopancreatography. A case report and review of the literature].

    PubMed

    Fernandez-Fernandez, J; Real-Noval, H; Rodriguez-Rodriguez, E

    2016-12-01

    Introduccion. La embolia aerea cerebral tras procesos endoscopicos es una complicacion infrecuente, pero que puede tener consecuencias catastroficas. Caso clinico. Varon de 85 años, diagnosticado de colangiocarcinoma distal con criterios de irresecabilidad, al cual se coloca una protesis biliar de drenaje. Se realiza una colangiopancreatografia retrograda endoscopica para el cambio de protesis. Tras el procedimiento, el paciente sufre un deterioro de las constantes vitales y del nivel de consciencia, y requiere intubacion orotraqueal. En la tomografia axial computarizada craneal se evidencia una embolia aerea masiva con focos de isquemia hiperaguda en ambos hemisferios. El paciente fallece posteriormente. Conclusiones. El embolismo aereo cerebral tras una colangiopancreatografia retrograda endoscopica es infrecuente, pero potencialmente letal. La manipulacion de la pared biliointestinal en las exploraciones endoscopicas podria originar comunicaciones entre la luz y el sistema venoso. Esto, unido a la alta presion de insuflacion para la realizacion de la prueba, condicionaria el paso de aire al sistema venoso portal y, de ahi, al sistema circulatorio. En el sistema nervioso central, las burbujas de aire provocarian una obstruccion vascular, con la consiguiente isquemia y necrosis del tejido. Es fundamental un diagnostico precoz y una terapia de soporte vital. Su rapido manejo puede contribuir a un mejor pronostico, que en principio es sombrio.

  5. Oxygen, a paradoxical element?

    PubMed

    Greabu, Maria; Battino, M; Mohora, Maria; Olinescu, R; Totan, Alexandra; Didilescu, Andreea

    2008-01-01

    Oxygen is an essential element for life on earth. No life may exist without oxygen. But in the last forty years, conclusive evidence demonstrated the double-edge sword of this element. In certain conditions, oxygen may produce reactive species, even free radicals. More, the production of reactive oxygen species (ROS) takes place everywhere: in air, nature or inside human bodies. The paradox of oxygen atom is entirely due to its peculiar electronic structure. But life began on earth, only when nature found efficient weapons against ROS, these antioxidants, which all creatures are extensibly endowed with. The consequences of oxygen activation in human bodies are only partly known, in spite of extensive scientific research on theoretical, experimental and clinical domains.

  6. The Integration Paradox

    PubMed Central

    Verkuyten, Maykel

    2016-01-01

    The integration paradox refers to the phenomenon of the more highly educated and structurally integrated immigrants turning away from the host society, rather than becoming more oriented toward it. This article provides an overview of the empirical evidence documenting this paradox in the Netherlands. In addition, the theoretical arguments and the available findings about the social psychological processes involved in this paradox are considered. The existing evidence for the integration paradox and what might explain it form the basis for making suggestion for future theoretical work and empirical research, and for discussing possible policy implications. PMID:27152028

  7. Aharonov-bohm paradox.

    NASA Technical Reports Server (NTRS)

    Trammel, G. T.

    1964-01-01

    Aharonov-bohm paradox involving charge particle interaction with stationary current distribution showing that vector potential term in canonical momenta expression represents electromagnetic field momentum

  8. Paradoxes in dermatology

    PubMed Central

    Adya, Keshavmurthy A.; Inamadar, Arun C.; Palit, Aparna

    2013-01-01

    Many paradoxical phenomena related to clinical, immunological, and therapeutic dermatology have been described. While some of them can be explained logically, the cause for others can only be speculated. Whenever encountered in clinical practice, background knowledge of such paradoxes may be useful to the clinician. PMID:23741675

  9. The Paradoxical Young Person

    ERIC Educational Resources Information Center

    Vishnevskii, Iu. R.; Shapko, V. T.

    2007-01-01

    The social transformations in Russian society in the past two decades have made relevant the problem of paradoxality, including its application to young people. The results of many years of sociological studies by the authors investigating the social problems of young people completely confirm Toshchenko's conclusion that "paradoxality of…

  10. Accretion of Saturn’s mid-sized moons during the viscous spreading of young massive rings: Solving the paradox of silicate-poor rings versus silicate-rich moons

    NASA Astrophysics Data System (ADS)

    Charnoz, Sébastien; Crida, Aurélien; Castillo-Rogez, Julie C.; Lainey, Valery; Dones, Luke; Karatekin, Özgür; Tobie, Gabriel; Mathis, Stephane; Le Poncin-Lafitte, Christophe; Salmon, Julien

    2011-12-01

    The origin of Saturn’s inner mid-sized moons (Mimas, Enceladus, Tethys, Dione and Rhea) and Saturn’s rings is debated. Charnoz et al. [Charnoz, S., Salmon J., Crida A., 2010. Nature 465, 752-754] introduced the idea that the smallest inner moons could form from the spreading of the rings’ edge while Salmon et al. [Salmon, J., Charnoz, S., Crida, A., Brahic, A., 2010. Icarus 209, 771-785] showed that the rings could have been initially massive, and so was the ring’s progenitor itself. One may wonder if the mid-sized moons may have formed also from the debris of a massive ring progenitor, as also suggested by Canup [Canup, R., 2010. Nature 468, 943-946]. However, the process driving mid-sized moon accretion from the icy debris disks has not been investigated in details. In particular, Canup’s (2010) model does not seem able to explain the varying silicate contents of the mid-sized moons (from 6% to 57% in mass). Here, we explore the formation of large objects from a massive ice-rich ring (a few times Rhea’s mass) and describe the fundamental properties and implications of this new process. Using a hybrid computer model, we show that accretion within massive icy rings can form all mid-sized moons from Mimas to Rhea. However in order to explain their current locations, intense dissipation within Saturn (with Qp < 2000) is required. Our results are consistent with a satellite origin tied to the rings formation at least 2.5 Gy ago, both compatible with either a formation concurrent to Saturn or during the Late Heavy Bombardment. Tidal heating related to high-eccentricity post-accretional episodes may induce early geological activity. If some massive irregular chunks of silicates were initially present within the rings, they would be present today inside the satellites’ cores which would have accreted icy shells while being tidally expelled from the rings (via a heterogeneous accretion process). These moons may be either mostly icy, or, if they contain a

  11. Thermal Expansion "Paradox."

    ERIC Educational Resources Information Center

    Fakhruddin, Hasan

    1993-01-01

    Describes a paradox in the equation for thermal expansion. If the calculations for heating a rod and subsequently cooling a rod are determined, the new length of the cool rod is shorter than expected. (PR)

  12. Length Paradox in Relativity

    ERIC Educational Resources Information Center

    Martins, Roberto de A.

    1978-01-01

    Describes a thought experiment using a general analysis approach with Lorentz transformations to show that the apparent self-contradictions of special relativity concerning the length-paradox are really non-existant. (GA)

  13. The core paradox.

    NASA Technical Reports Server (NTRS)

    Kennedy, G. C.; Higgins, G. H.

    1973-01-01

    Rebuttal of suggestions from various critics attempting to provide an escape from the seeming paradox originated by Higgins and Kennedy's (1971) proposed possibility that the liquid in the outer core was thermally stably stratified and that this stratification might prove a powerful inhibitor to circulation of the outer core fluid of the kind postulated for the generation of the earth's magnetic field. These suggestions are examined and shown to provide no reasonable escape from the core paradox.

  14. The quercetin paradox

    SciTech Connect

    Boots, Agnes W. . E-mail: a.boots@farmaco.unimaas.nl; Li, Hui; Schins, Roel P.F.; Duffin, Rodger; Heemskerk, Johan W.M.; Bast, Aalt; Haenen, Guido R.M.M.

    2007-07-01

    Free radical scavenging antioxidants, such as quercetin, are chemically converted into oxidation products when they protect against free radicals. The main oxidation product of quercetin, however, displays a high reactivity towards thiols, which can lead to the loss of protein function. The quercetin paradox is that in the process of offering protection, quercetin is converted into a potential toxic product. In the present study, this paradox is evaluated using rat lung epithelial (RLE) cells. It was found that quercetin efficiently protects against H{sub 2}O{sub 2}-induced DNA damage in RLE cells, but this damage is swapped for a reduction in GSH level, an increase in LDH leakage as well as an increase of the cytosolic free calcium concentration. To our knowledge, this is the first study that indicates that the quercetin paradox, i.e. the exchange of damage caused by quercetin and its metabolites, also occurs in living lung cells. Following depletion of GSH in the cells by BSO pre-treatment, this quercetin paradox becomes more pronounced, confirming that the formation of thiol reactive quercetin metabolites is involved in the quercetin paradox. The quercetin paradox in living cells implies that the anti-oxidant directs oxidative damage selectively to thiol arylation. Apparently, the potential toxicity of metabolites formed during the actual antioxidant activity of free radical scavengers should be considered in antioxidant supplementation.

  15. Zeno's Paradox of Immortality.

    PubMed

    Olshansky, S Jay; Carnes, Bruce A

    2013-01-01

    Scientists who speculate on the future of human longevity have a broad range of views ranging from the promise of immortality, to radical life extension, to declines in life expectancy. Among those who contend that radical life extension is already here, or on the horizon, or immortality is forthcoming, elements of their reasoning appear surprisingly close, if not identical, to a famous mathematical paradox posed by the ancient Greek mathematician known as Zeno. Here we examine the underlying assumptions behind the views that much longer life expectancies are forthcoming or have already arrived, and place their line of reasoning within the context of a new Zeno paradox described here as The Paradox of Immortality.

  16. Black Hole Paradoxes

    NASA Astrophysics Data System (ADS)

    Joshi, Pankaj S.; Narayan, Ramesh

    2016-10-01

    We propose here that the well-known black hole paradoxes such as the information loss and teleological nature of the event horizon are restricted to a particular idealized case, which is the homogeneous dust collapse model. In this case, the event horizon, which defines the boundary of the black hole, forms initially, and the singularity in the interior of the black hole at a later time. We show that, in contrast, gravitational collapse from physically more realistic initial conditions typically leads to the scenario in which the event horizon and space-time singularity form simultaneously. We point out that this apparently simple modification can mitigate the causality and teleological paradoxes, and also lends support to two recently suggested solutions to the information paradox, namely, the ‘firewall’ and ‘classical chaos’ proposals.

  17. [Disseminated arterial occlusions revealing bilateral venous thrombosis with paradoxical embolisms].

    PubMed

    Elsendoorn, A; Desport, E; Vialle, R; Frat, J-P; Bridoux, F; Touchard, G

    2009-06-01

    Paradoxical embolism is a diagnosis of exclusion. Clinical triad associates deep venous thrombosis with or without pulmonary embolism, arterial embolism, and intracardiac communication with right-to-left shunt. The intracardiac communication is generally related to a patent foramen ovale (PFO). We report a 75-year-old patient, who presented with bilateral deep venous thrombosis of the legs, complicated by massive pulmonary embolism and paradoxical embolisms through a PFO. This resulted in cerebral, mesenteric, splenic and bilateral kidney infarctions. A promptly initiated anticoagulant treatment allowed a favourable outcome.

  18. Massive Stars

    NASA Astrophysics Data System (ADS)

    Livio, Mario; Villaver, Eva

    2009-11-01

    Participants; Preface Mario Livio and Eva Villaver; 1. High-mass star formation by gravitational collapse of massive cores M. R. Krumholz; 2. Observations of massive star formation N. A. Patel; 3. Massive star formation in the Galactic center D. F. Figer; 4. An X-ray tour of massive star-forming regions with Chandra L. K. Townsley; 5. Massive stars: feedback effects in the local universe M. S. Oey and C. J. Clarke; 6. The initial mass function in clusters B. G. Elmegreen; 7. Massive stars and star clusters in the Antennae galaxies B. C. Whitmore; 8. On the binarity of Eta Carinae T. R. Gull; 9. Parameters and winds of hot massive stars R. P. Kudritzki and M. A. Urbaneja; 10. Unraveling the Galaxy to find the first stars J. Tumlinson; 11. Optically observable zero-age main-sequence O stars N. R. Walborn; 12. Metallicity-dependent Wolf-Raynet winds P. A. Crowther; 13. Eruptive mass loss in very massive stars and Population III stars N. Smith; 14. From progenitor to afterlife R. A. Chevalier; 15. Pair-production supernovae: theory and observation E. Scannapieco; 16. Cosmic infrared background and Population III: an overview A. Kashlinsky.

  19. The local environment resulting from a massive nuclear attack on Whiteman Air Force Base. Final technical report

    SciTech Connect

    Hulburt, C.W.; Yutko, C.A.; Sullivan, R.J.

    1980-04-01

    The study examines the potential blast and fallout damage that would be sustained by the 15 counties surrounding the Whiteman Air Force Base in Missouri following a nuclear attack against the associated Minuteman missile silos. The study also provides recommendations concerning the shelters that would be required to protect the population of these 15 counties from blast effects and heavy fallout. The study was performed in consonance with the new emphasis that FEMA (Federal Emergency Management Agency) is giving to nuclear civil protection in counterforce areas. It is intended to be a prototype for analyses of areas containing other U.S. counterforce targets, notably the other five Minuteman wings, the Titan missiles, the Strategic Air Command bases, and the strategic submarine bases.

  20. A Hydrostatic Paradox Revisited

    ERIC Educational Resources Information Center

    Ganci, Salvatore

    2012-01-01

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

  1. Adventures in Paradox

    ERIC Educational Resources Information Center

    Lynch, Pip; Moore, Kevin

    2004-01-01

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

  2. Postradiation hypertrichosis: a paradox.

    PubMed

    Agarwal, Jai Prakash; Upasani, Maheshkumar N; Ghadi, Yogesh; Munshi, Anusheel

    2014-01-01

    Alopecia due to radiation has remained a widely accepted aspect of radiotherapy. We present an unexpected clinical scenario, where a patient with left lung stage IIIB nonsmall cell adenocarcinoma, treated with radiochemotherapy achieved a complete response and developed an obscure late effect in terms of paradoxical hypertrichosis in the radiation portals. The paper presents plausible hypothesis for this unusual phenomenon.

  3. Massive Hemoptysis.

    PubMed

    Rali, Parth; Gandhi, Viral; Tariq, Cheema

    2016-01-01

    Hemoptysis, or coughing of blood, oftentimes triggers anxiety and fear for patients. The etiology of hemoptysis will determine the clinical course, which includes watchful waiting or intensive care admission. Any amount of hemoptysis that compromises the patient's respiratory status is considered massive hemoptysis and should be considered a medical emergency. In this article, we review introduction, definition, bronchial circulation anatomy, etiology, and management of massive hemoptysis.

  4. Pentagrams and Paradoxes

    NASA Astrophysics Data System (ADS)

    Badziaģ, Piotr; Bengtsson, Ingemar; Cabello, Adán; Granström, Helena; Larsson, Jan-Åke

    2011-03-01

    Klyachko and coworkers consider an orthogonality graph in the form of a pentagram, and in this way derive a Kochen-Specker inequality for spin 1 systems. In some low-dimensional situations Hilbert spaces are naturally organised, by a magical choice of basis, into SO( N) orbits. Combining these ideas some very elegant results emerge. We give a careful discussion of the pentagram operator, and then show how the pentagram underlies a number of other quantum "paradoxes", such as that of Hardy.

  5. The Bohr paradox

    NASA Astrophysics Data System (ADS)

    Crease, Robert P.

    2008-05-01

    In his book Niels Bohr's Times, the physicist Abraham Pais captures a paradox in his subject's legacy by quoting three conflicting assessments. Pais cites Max Born, of the first generation of quantum physics, and Werner Heisenberg, of the second, as saying that Bohr had a greater influence on physics and physicists than any other scientist. Yet Pais also reports a distinguished younger colleague asking with puzzlement and scepticism "What did Bohr really do?".

  6. Autophagy Paradox and Ceramide

    PubMed Central

    Jiang, Wenhui; Ogretmen, Besim

    2013-01-01

    Sphingolipid molecules act as bioactive lipid messengers and exert their actions on the regulation of various cellular signaling pathways. Sphingolipids play essential roles in numerous cellular functions, including controlling cell inflammation, proliferation, death, migration, senescence, tumor metastasis and/or autophagy. Dysregulated sphingolipid metabolism has been also implicated in many human cancers. Macroatuophagy (referred to here as autophagy) “self-eating”, is characterized by nonselective sequestering of cytosolic materials by an isolation membrane, which can be either protective or lethal for cells. Ceramide (Cer), a central molecule of sphingolipid metabolism, has been extensively implicated in the control of autophagy. The increasing evidence suggests Cer is highly involved in mediating two opposing autophagic pathways, which regulate either cell survival or death, autophagy paradox. However, the underlying mechanism that regulates the autophagy paradox remains unclear. Therefore, this review focuses on recent studies with regard to the regulation of autophagy by Cer and elucidate the roles and mechanisms of action of Cer in controlling autophagy paradox. PMID:24055889

  7. Air

    MedlinePlus

    ... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

  8. The paradox of Schrodinger's cat

    NASA Astrophysics Data System (ADS)

    Villars, C. N.

    1986-07-01

    Erwin Schrodinger first described the thought-experiment which has since become known as 'the paradox of Schrodinger's cat' 51 years ago. In recent years, popular accounts of quantum mechanics have tended to adopt one or other of the philosophically most extreme solutions to this paradox, i.e. the consciousness hypothesis or the many worlds interpretation. The author attempts to redress the balance by describing what he takes to be the orthodox solution to the paradox which explains the paradox, without recourse to such counterintuitive notions as a cat simultaneously dead and alive or a universe continually splitting into multiple worlds, as being due to a misapplication of the quantum formalism.

  9. The Easterlin paradox revisited.

    PubMed

    Frank, Robert H

    2012-12-01

    The traditional view that well-being depends on both absolute and relative income was challenged in a 1974 paper by Richard Easterlin (Does economic growth improve the human lot? In P. David and M. Reder (Eds.), Nations and households in economic growth: Essays in honor of Moses Abramovitz (pp. 89-125), New York: Academic Press). He noted that although individual well-being is strongly positively associated with income within any country at a given point in time, the average level of measured well-being for a country changes little over time, even in the face of substantial growth in average incomes. For decades, social scientists have struggled to explain this "Easterlin Paradox." In a 2008 paper, Betsey Stephenson and Justin Wolfers (Economic growth and subjective well-being: Reassessing the Easterlin Paradox, Brookings Papers on Economic Activity, Vol. 39, pp. 1-87) argued that the Easterlin Paradox was a statistical illusion. Using richer data sets that facilitate more precise estimates of the various links between income and well-being, they assert that average well-being in a country does, in fact, rise as average income rises over time, and that rich countries are happier than slightly poorer ones. They also suggest that the link between income and well-being may run through absolute income alone-that is, that individual well-being may be completely independent of relative income. In this article, I argue that there have always been good reasons to believe that well-being is positively linked to absolute income. I also argue, however, that there is no reason to believe that individual well-being is independent of relative income.

  10. The Teacher's Paradox

    NASA Astrophysics Data System (ADS)

    Lilyquist, J. Gary

    1998-06-01

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

  11. Barn and Pole Paradox: Revisited

    ERIC Educational Resources Information Center

    Cacioppo, Robert; Gangopadhyaya, Asim

    2012-01-01

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

  12. Understanding Schroeder's Paradox

    NASA Astrophysics Data System (ADS)

    Weber, Adam; Kusoglu, Ahmet

    2012-02-01

    Schroeder's paradox is a well known, but not fully understood, phenomenon that exists in many polymers and gels. Essentially, the uptake of solvent in the polymer depends on the interaction with the boundary phase. Nafion, a polymer of interest for many electrochemical energy applications, is a classic example where the water uptake almost doubles by placement in liquid water versus saturated water vapor. In this talk, we examine the origin of this paradox through examination of Nafion morphology and water-uptake time constants using experiments in various solvents, vacuum, and small-angle X-ray scattering techniques. The results show that the interface controls the water uptake (even in bulk membranes) and that the interfacial morphology depends on the interactions of the different polymer moieties with the external environment including its density and dielectric constant. In addition, interactions with solid phases will be discussed which show similar impact on water uptake depending on whether they are hydrophilic or hydrophobic. Understanding the morphological changes and their associated impact on membrane properties is critical for optimizing polymers for use in energy applications.

  13. China's Innovation Paradox

    ERIC Educational Resources Information Center

    Chan, Jeremy

    2015-01-01

    China aims to become an innovation-led nation by 2020, but its leadership is generally sceptical--and oftentimes hostile--to the market forces, open exchange of ideas, and creative destruction that have unlocked innovation in other countries. Instead, Beijing hopes to promote innovation in China through a massive expansion in higher education,…

  14. Resveratrol: French Paradox Revisited

    PubMed Central

    Catalgol, Betul; Batirel, Saime; Taga, Yavuz; Ozer, Nesrin Kartal

    2012-01-01

    Resveratrol is a polyphenol that plays a potentially important role in many disorders and has been studied in different diseases. The research on this chemical started through the “French paradox,” which describes improved cardiovascular outcomes despite a high-fat diet in French people. Since then, resveratrol has been broadly studied and shown to have antioxidant, anti-inflammatory, anti-proliferative, and anti-angiogenic effects, with those on oxidative stress possibly being most important and underlying some of the others, but many signaling pathways are among the molecular targets of resveratrol. In concert they may be beneficial in many disorders, particularly in diseases where oxidative stress plays an important role. The main focus of this review will be the pathways affected by resveratrol. Based on these mechanistic considerations, the involvement of resveratrol especially in cardiovascular diseases, cancer, neurodegenerative diseases, and possibly in longevity will be is addressed. PMID:22822401

  15. Paradoxes of neutrino oscillations

    SciTech Connect

    Akhmedov, E. Kh.; Smirnov, A. Yu.

    2009-08-15

    Despite the theory of neutrino oscillations being rather old, some of its basic issues are still being debated in the literature. We discuss a number of such issues, including the relevance of the 'same energy' and 'same momentum' assumptions, the role of quantum-mechanical uncertainty relations in neutrino oscillations, the dependence of the coherence and localization conditions that ensure the observability of neutrino oscillations on neutrino energy and momentum uncertainties, the question of (in)dependence of the oscillation probabilities on the neutrino production and detection processes, and the applicability limits of the stationary-source approximation. We also develop a novel approach to calculation of the oscillation probability in the wave-packet approach, based on the summation/integration conventions different from the standard one, which allows a new insight into the 'same energy' vs. 'same momentum' problem. We also discuss a number of apparently paradoxical features of the theory of neutrino oscillations.

  16. The lunar apatite paradox.

    PubMed

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

    2014-04-25

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

  17. The Fermi Paradox Is Neither Fermi's Nor a Paradox

    NASA Astrophysics Data System (ADS)

    Gray, Robert H.

    2015-03-01

    The so-called Fermi paradox claims that if technological life existed anywhere else, we would see evidence of its visits to Earth-and since we do not, such life does not exist, or some special explanation is needed. Enrico Fermi, however, never published anything on this topic. On the one occasion he is known to have mentioned it, he asked 'where is everybody?'- apparently suggesting that we don't see extraterrestrials on Earth because interstellar travel may not be feasible, but not suggesting that intelligent extraterrestrial life does not exist, or suggesting its absence is paradoxical. The claim 'they are not here; therefore they do not exist' was first published by Michael Hart, claiming that interstellar travel and colonization of the galaxy would be inevitable if intelligent extraterrestrial life existed, and taking its absence here as proof that it does not exist anywhere. The Fermi paradox appears to originate in Hart's argument, not Fermi's question. Clarifying the origin of these ideas is important, because the Fermi paradox is seen by some as an authoritative objection to searching for evidence of extraterrestrial intelligence-cited in the U. S. Congress as a reason for killing NASA's SETI program on one occasion-but evidence indicates that it misrepresents Fermi's views, misappropriates his authority, deprives the actual authors of credit, and is not a valid paradox. Keywords: Astrobiology, SETI, Fermi paradox, extraterrestrial life

  18. Explaining the harmonic sequence paradox.

    PubMed

    Schmidt, Ulrich; Zimper, Alexander

    2012-05-01

    According to the harmonic sequence paradox, an expected utility decision maker's willingness to pay for a gamble whose expected payoffs evolve according to the harmonic series is finite if and only if his marginal utility of additional income becomes zero for rather low payoff levels. Since the assumption of zero marginal utility is implausible for finite payoff levels, expected utility theory - as well as its standard generalizations such as cumulative prospect theory - are apparently unable to explain a finite willingness to pay. This paper presents first an experimental study of the harmonic sequence paradox. Additionally, it demonstrates that the theoretical argument of the harmonic sequence paradox only applies to time-patient decision makers, whereas the paradox is easily avoided if time-impatience is introduced.

  19. A Magnetic Paradox

    ERIC Educational Resources Information Center

    Arndt, Ebe

    2006-01-01

    Two recent articles in this journal described how an air core solenoid connected to an ac power source may restore the magnetization of a bar magnet with an alternating magnetic field (see Figs. 1 and 2). Although we are quite accustomed to using a constant magnetic field in an air core solenoid to remagnetize a ferromagnet, it is puzzling that we…

  20. The Statistical Fermi Paradox

    NASA Astrophysics Data System (ADS)

    Maccone, C.

    In this paper is provided the statistical generalization of the Fermi paradox. The statistics of habitable planets may be based on a set of ten (and possibly more) astrobiological requirements first pointed out by Stephen H. Dole in his book Habitable planets for man (1964). The statistical generalization of the original and by now too simplistic Dole equation is provided by replacing a product of ten positive numbers by the product of ten positive random variables. This is denoted the SEH, an acronym standing for “Statistical Equation for Habitables”. The proof in this paper is based on the Central Limit Theorem (CLT) of Statistics, stating that the sum of any number of independent random variables, each of which may be ARBITRARILY distributed, approaches a Gaussian (i.e. normal) random variable (Lyapunov form of the CLT). It is then shown that: 1. The new random variable NHab, yielding the number of habitables (i.e. habitable planets) in the Galaxy, follows the log- normal distribution. By construction, the mean value of this log-normal distribution is the total number of habitable planets as given by the statistical Dole equation. 2. The ten (or more) astrobiological factors are now positive random variables. The probability distribution of each random variable may be arbitrary. The CLT in the so-called Lyapunov or Lindeberg forms (that both do not assume the factors to be identically distributed) allows for that. In other words, the CLT "translates" into the SEH by allowing an arbitrary probability distribution for each factor. This is both astrobiologically realistic and useful for any further investigations. 3. By applying the SEH it is shown that the (average) distance between any two nearby habitable planets in the Galaxy may be shown to be inversely proportional to the cubic root of NHab. This distance is denoted by new random variable D. The relevant probability density function is derived, which was named the "Maccone distribution" by Paul Davies in

  1. The fermi paradox is neither Fermi's nor a paradox.

    PubMed

    Gray, Robert H

    2015-03-01

    The so-called Fermi paradox claims that if technological life existed anywhere else, we would see evidence of its visits to Earth--and since we do not, such life does not exist, or some special explanation is needed. Enrico Fermi, however, never published anything on this topic. On the one occasion he is known to have mentioned it, he asked "Where is everybody?"--apparently suggesting that we do not see extraterrestrials on Earth because interstellar travel may not be feasible, but not suggesting that intelligent extraterrestrial life does not exist or suggesting its absence is paradoxical. The claim "they are not here; therefore they do not exist" was first published by Michael Hart, claiming that interstellar travel and colonization of the Galaxy would be inevitable if intelligent extraterrestrial life existed, and taking its absence here as proof that it does not exist anywhere. The Fermi paradox appears to originate in Hart's argument, not Fermi's question. Clarifying the origin of these ideas is important, because the Fermi paradox is seen by some as an authoritative objection to searching for evidence of extraterrestrial intelligence--cited in the U.S. Congress as a reason for killing NASA's SETI program on one occasion. But evidence indicates that it misrepresents Fermi's views, misappropriates his authority, deprives the actual authors of credit, and is not a valid paradox.

  2. The helium paradoxes.

    PubMed

    Anderson, D L

    1998-04-28

    The ratio 3He/4He (R) plays a central role in models of mantle evolution that propose an undegassed lower mantle, rich in the primordial isotope 3He. A large primordial volatile-rich reservoir, a feature of recent models, is inconsistent with high-temperature accretion and with estimates of crustal and bulk Earth chemistry. High R can alternatively reflect high integrated 3He/(U+Th) ratios or low 4He abundances, as expected in refractory portions of the upper mantle. I show that high R materials are gas-poor and are deficient in radiogenic 4He compared with midocean ridge basalts. The seemingly primitive (i.e., high R) signatures in "hotspot" magmas may be secondary, derived from CO2-rich gases, or residual peridotite, a result of differential partitioning of U and He into magmas. A shallow and low 3He source explains the spatial variability and the temporal trends of R in ocean islands and is consistent with a volatile-poor planet. A shallow origin for the "primitive" He signature in ocean island basalts, such as at Loihi, reconciles the paradoxical juxtaposition of crustal, seawater, and atmospheric signatures with inferred "primitive" characteristics. High 238U/204Pb components in ocean island basalts are generally attributed to recycled altered oceanic crust. The low 238U/3He component may be in the associated depleted refractory mantle. High 3He/4He ratios are due to low 4He, not excess 3He, and do not imply or require a deep or primordial or undegassed reservoir. 40Ar in the atmosphere also argues against such models.

  3. Paradoxical and bidirectional drug effects.

    PubMed

    Smith, Silas W; Hauben, Manfred; Aronson, Jeffrey K

    2012-03-01

    A paradoxical drug reaction constitutes an outcome that is opposite from the outcome that would be expected from the drug's known actions. There are three types: 1. A paradoxical response in a condition for which the drug is being explicitly prescribed. 2. Paradoxical precipitation of a condition for which the drug is indicated, when the drug is being used for an alternative indication. 3. Effects that are paradoxical in relation to an aspect of the pharmacology of the drug but unrelated to the usual indication. In bidirectional drug reactions, a drug may produce opposite effects, either in the same or different individuals, the effects usually being different from the expected beneficial effect. Paradoxical and bidirectional drug effects can sometimes be harnessed for benefit; some may be adverse. Such reactions arise in a wide variety of drug classes. Some are common; others are reported in single case reports. Paradoxical effects are often adverse, since they are opposite the direction of the expected effect. They may complicate the assessment of adverse drug reactions, pharmacovigilance, and clinical management. Bidirectional effects may be clinically useful or adverse. From a clinical toxicological perspective, altered pharmacokinetics or pharmacodynamics in overdose may exacerbate paradoxical and bidirectional effects. Certain antidotes have paradoxical attributes, complicating management. Apparent clinical paradoxical or bidirectional effects and reactions ensue when conflicts arise at different levels in self-regulating biological systems, as complexity increases from subcellular components, such as receptors, to cells, tissues, organs, and the whole individual. These may be incompletely understood. Mechanisms of such effects include different actions at the same receptor, owing to changes with time and downstream effects; stereochemical effects; multiple receptor targets with or without associated temporal effects; antibody-mediated reactions; three

  4. Biochemical pharmacology of paradoxical sleep

    PubMed Central

    Gaillard, J. -M.

    1983-01-01

    1 The role of noradrenergic cells in the regulation of paradoxical sleep is still controversial, and experimental data have given rise to contradictory interpretations. 2 Early investigations focused primarily on chemical neurotransmissions. However, the process of information transmission between cells involves many other factors, and the cell surface is an important site for transduction of messages into modifications of the activity of postsynaptic cells. 3 α-adrenoceptors are believed to play an important role in the control of wakefulness and paradoxical sleep. Experimental evidence suggests that physiological modulation of receptor sensitivity, possibly by specific neuro-modulators, may be a key mechanism in synaptic transmission. 4 In the investigation of the mechanisms involved in paradoxical sleep regulation, lesions of the locus coeruleus have given equivocal results. Collateral inhibition, probably mediated by α2-adrenoceptors, appears to be a powerful mechanism. The exact temporal relationship between noradrenergic cell activation and paradoxical sleep production is not established, but 5-HT appears to be involved. Differences between paradoxical sleep and waking may be related to a physiological modulation of α2-adrenoceptor sensitivity. PMID:6140943

  5. An Acid Hydrocarbon: A Chemical Paradox

    ERIC Educational Resources Information Center

    Burke, Jeffrey T.

    2004-01-01

    The chemical paradox of cyclopentadiene, a hydrocarbon, producing bubbles like a Bronsted acid is observed. The explanation that it is the comparative thermodynamic constancy of the fragrant cyclopentadienyl anion, which produces the powerful effect, resolves the paradox.

  6. Broadbeam for Massive MIMO Systems

    NASA Astrophysics Data System (ADS)

    Qiao, Deli; Qian, Haifeng; Li, Geoffrey Ye

    2016-05-01

    Massive MIMO has been identified as one of the promising disruptive air interface techniques to address the huge capacity requirement demanded by 5G wireless communications. For practical deployment of such systems, the control message need to be broadcast to all users reliably in the cell using broadbeam. A broadbeam is expected to have the same radiated power in all directions to cover users in any place in a cell. In this paper, we will show that there is no perfect broadbeam. Therefore, we develop a method for generating broadbeam that can allow tiny fluctuations in radiated power. Overall, this can serve as an ingredient for practical deployment of the massive MIMO systems.

  7. Classical three-box 'paradox'

    NASA Astrophysics Data System (ADS)

    Kirkpatrick, K. A.

    2003-05-01

    A simple classical probabilistic system (a simple card game) classically exemplifies Aharonov and Vaidman's 'three-box 'paradox'' (1991 J. Phys. A: Math. Gen. 24 2315), implying that the three-box example is neither quantal nor a paradox and leaving one with less difficulty to busy the interpreters of quantum mechanics. An ambiguity in the usual expression of the retrodiction formula is shown to have misled Albert et al (1985 Phys. Rev. Lett. 54 5) to a result not, in fact, 'curious'; the discussion illustrates how to avoid this ambiguity.

  8. Teaching Quantum Physics without Paradoxes

    ERIC Educational Resources Information Center

    Hobson, Art

    2007-01-01

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

  9. CCC and the Fermi paradox

    NASA Astrophysics Data System (ADS)

    Gurzadyan, V. G.; Penrose, R.

    2016-01-01

    Within the scheme of conformal cyclic cosmology (CCC), information can be transmitted from aeon to aeon. Accordingly, the "Fermi paradox" and the SETI programme --of communication by remote civilizations-- may be examined from a novel perspective: such information could, in principle, be encoded in the cosmic microwave background. The current empirical status of CCC is also discussed.

  10. Economics and the Fermi Paradox

    NASA Astrophysics Data System (ADS)

    Hosek, W. R.

    A resolution of the Fermi paradox is proposed using common economic assumptions that should apply to all intelligent, planet-bound civilizations. It is argued that seemingly rational decisions about resource allocation will lead all civilizations to forego the commitment to interstellar exploration and colonization. Consequently humans have not, and will not, be visited by them and humans will not visit other civilizations.

  11. Mechanical Paradox: The Uphill Roller

    ERIC Educational Resources Information Center

    Cortes, Emilio; Cortes-Poza, D.

    2011-01-01

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

  12. The Paradox of Case Study.

    ERIC Educational Resources Information Center

    Simons, Helen

    1996-01-01

    Examines the paradox of case studies' abilities to understand the complexity in particular contexts while not being generalizable. Argues that the pressure for quantification and multisite case study design in policy research has weakened the original utility of the case study method for understanding complex educational phenomena. (DSK)

  13. Review Essay: Pondering Pedagogical Paradoxes

    ERIC Educational Resources Information Center

    Spencer, Leland G.

    2015-01-01

    Herein, Leland Spencer provides a review of four book selections while reflecting on paradoxes regularly faced by feminist teachers (and scholars, activists, and thinkers). The books include: (1) Bradley, Harriet. "Gender." Cambridge: Polity, 2012. Print; (2) Murphy, Michael J., and Elizabeth N. Ribarsky, eds. "Activities for…

  14. The Paradox of Painful Art

    ERIC Educational Resources Information Center

    Smuts, Aaron

    2007-01-01

    Many of the most popular genres of narrative art are designed to elicit negative emotions: emotions that are experienced as painful or involving some degree of pain, which people generally avoid in their daily lives. Traditionally, the question of why people seek out such experiences of painful art has been presented as the paradox of tragedy, and…

  15. Paradoxical Results and Item Bundles

    ERIC Educational Resources Information Center

    Hooker, Giles; Finkelman, Matthew

    2010-01-01

    Hooker, Finkelman, and Schwartzman ("Psychometrika," 2009, in press) defined a paradoxical result as the attainment of a higher test score by changing answers from correct to incorrect and demonstrated that such results are unavoidable for maximum likelihood estimates in multidimensional item response theory. The potential for these results to…

  16. Colloquium: The Einstein-Podolsky-Rosen paradox: From concepts to applications

    SciTech Connect

    Reid, M. D.; Drummond, P. D.; Bowen, W. P.; Cavalcanti, E. G.; Lam, P. K.; Bachor, H. A.; Andersen, U. L.; Leuchs, G.

    2009-10-15

    This Colloquium examines the field of the Einstein, Podolsky, and Rosen (EPR) gedanken experiment, from the original paper of Einstein, Podolsky, and Rosen, through to modern theoretical proposals of how to realize both the continuous-variable and discrete versions of the EPR paradox. The relationship with entanglement and Bell's theorem are analyzed, and the progress to date towards experimental confirmation of the EPR paradox is summarized, with a detailed treatment of the continuous-variable paradox in laser-based experiments. Practical techniques covered include continuous-wave parametric amplifier and optical fiber quantum soliton experiments. Current proposals for extending EPR experiments to massive-particle systems are discussed, including spin squeezing, atomic position entanglement, and quadrature entanglement in ultracold atoms. Finally, applications of this technology to quantum key distribution, quantum teleportation, and entanglement swapping are examined.

  17. Protective effect of adenosine against a calcium paradox in the isolated frog heart.

    PubMed

    Touraki, M; Lazou, A

    1992-01-01

    The effect of adenosine on the calcium paradox in the isolated frog heart was studied. Addition of adenosine during calcium depletion protected the frog heart against a calcium paradox. This protective effect was indicated by reduced protein and creatine kinase release, maintenance of electrical activity, and recovery of mechanical activity during reperfusion. Tissue calcium determination results showed that adenosine protected frog myocardial cells by reducing the massive calcium influx during reperfusion possibly through an action on calcium channels. Adenosine exerted its action in a dose-dependent manner; a concentration of 10 microM adenosine provided maximum protection of myocardial cells against the calcium paradox damage. Higher concentrations of adenosine produced side effects on both electrical and mechanical activity. These results are discussed in terms of the possible mechanism involved in the protective effect of adenosine.

  18. Quantum-mechanical twin paradox

    NASA Astrophysics Data System (ADS)

    Franson, J. D.

    2016-10-01

    In the twin paradox of special relativity, an observer that travels along an accelerated trajectory at a high velocity will experience a smaller amount of elapsed time than an observer that remains at rest. This illustrates the fact that time is relative unlike the situation in classical physics where time is absolute. In a recent paper, Bushev et al (2016 New J. Phys. 18 093050) showed that the twin paradox can also be demonstrated using a single electron that functions as a quantum-mechanical clock. The wave function of the electron can travel along two different paths simultaneously, which allows a measurement of the difference in proper times along the two trajectories using a single particle. Quantum interference effects show that time cannot be thought of as a classical parameter even when associated with a single clock or observer.

  19. The paradoxical nature of surrender.

    PubMed

    Holley, Dorothy E Adamson

    2007-01-01

    Surrender is one of the most fundamental, important aspects of spirituality and of integration. It is crucial to our relationship to God, to self, and to others. While surrender is essential for any real attempt at authenticity and integration, it is also one of the most challenging aspects of any spiritual pursuit or endeavor. The inability or unwillingness to surrender is a serious impediment to our relationship with God, with others, and even with ourselves. Paradoxically, there is great freedom and an increased sense of control that is experienced when one is able to surrender. This article explores two themes that the author believes are involved in surrender: fear and trust. Clinical as well as personal examples of the paradoxical nature and transformational power of surrender are offered.

  20. Paradoxical emboli in elderly patients.

    PubMed

    Vella, M; McNabb, R; Lewis, R; Sulke, N; Poston, R; Lugon, M

    1992-01-01

    We report two elderly patients who each had a patent foramen ovale (PFO) and were considered to have had paradoxical emboli. In one patient the PFO was detected by contrast two-dimensional echocardiography, whereas in the other it was demonstrated at post-mortem examination. This is an unusual but treatable condition, particularly difficult to diagnose in older people and probably occurring more frequently than is generally suspected.

  1. Reinterpretaion of the friendship paradox

    NASA Astrophysics Data System (ADS)

    Fu, Jingcheng; Wu, Jianliang

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

  2. Massive transfusion and massive transfusion protocol

    PubMed Central

    Patil, Vijaya; Shetmahajan, Madhavi

    2014-01-01

    Haemorrhage remains a major cause of potentially preventable deaths. Rapid transfusion of large volumes of blood products is required in patients with haemorrhagic shock which may lead to a unique set of complications. Recently, protocol based management of these patients using massive transfusion protocol have shown improved outcomes. This section discusses in detail both management and complications of massive blood transfusion. PMID:25535421

  3. Multisetting Greenberger-Horne-Zeilinger paradoxes

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

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

  4. Discriminatory Air Pollution

    ERIC Educational Resources Information Center

    McCaull, Julian

    1976-01-01

    Described are the patterns of air pollution in certain large urban areas. Persons in poverty, in occupations below the management or professional level, in low-rent districts, and in black population are most heavily exposed to air pollution. Pollution paradoxically is largely produced by high energy consuming middle-and upper-class households.…

  5. Bioterrorism and the Fermi Paradox

    NASA Astrophysics Data System (ADS)

    Cooper, Joshua

    2013-04-01

    We proffer a contemporary solution to the so-called Fermi Paradox, which is concerned with conflict between Copernicanism and the apparent paucity of evidence for intelligent alien civilizations. In particular, we argue that every community of organisms that reaches its space-faring age will (1) almost immediately use its rocket-building computers to reverse-engineer its genetic chemistry and (2) self-destruct when some individual uses said technology to design an omnicidal pathogen. We discuss some of the possible approaches to prevention with regard to Homo sapiens' vulnerability to bioterrorism, particularly on a short-term basis.

  6. Burnt Water Paradoxes of Schools of Education.

    ERIC Educational Resources Information Center

    Blackwell, Peggy L.; Futrell, Mary H.; Imig, David G.

    2003-01-01

    Discusses historical underpinnings of five "burnt water" paradoxes representing both destruction (burning) and life (water): professionalism, teaching and learning, market and standards, social justice and diversity, and change. Asserts that "burnt water" paradoxes are greatest challenges facing schools of education in 21st century. (Contains 22…

  7. Advocacy: Catching and Using the Paradox

    ERIC Educational Resources Information Center

    Kaplan, Sandra

    2002-01-01

    Successful advocates are able to identify a paradox in the context of a statement or discussion and use it to reinforce or change an opinion. Embedded in the discussion held by educators and parents, are often self-contradictory statements. Educators listening to the presentation of educational ideas that oppose each other can use the paradox to…

  8. Virtue Acquisition: The Paradox of Striving

    ERIC Educational Resources Information Center

    Snow, Nancy

    2016-01-01

    Aristotelian-inspired accounts of virtue acquisition stress guided practice and habituated action to develop virtue. This emphasis on action can lead to the "paradox of striving". The paradox occurs when we try too hard to act well and thereby spoil our efforts. I identify four forms of striving--forcing, impulsivity, overthinking, and…

  9. The twin paradox and Mach's principle

    NASA Astrophysics Data System (ADS)

    Lichtenegger, H.; Iorio, L.

    2011-12-01

    The problem of absolute motion in the context of the twin paradox is discussed. It is shown that the various versions of the clock paradox feature some aspects which Mach might have appreciated. However, the ultimate cause of the behavior of the clocks must be attributed to the autonomous status of spacetime, thereby proving the relational program advocated by Mach as impracticable.

  10. Dewey, Peirce, and the Learning Paradox.

    ERIC Educational Resources Information Center

    Prawat, Richard S.

    1999-01-01

    Proposes a solution to the learning paradox (how learning develops from prior learning) that is based on the work of C. Peirce and J. Dewey. Ideas, as opposed to schemas or postmodernist discourse, are viewed as the real carriers of meaning. Abduction offers the best chance of coming to terms with the paradox. Contains 78 references. (Author/SLD)

  11. [Five paradoxes in health promotion].

    PubMed

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

    2017-02-17

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

  12. Higher dimensional massive bigravity

    NASA Astrophysics Data System (ADS)

    Do, Tuan Q.

    2016-08-01

    We study higher-dimensional scenarios of massive bigravity, which is a very interesting extension of nonlinear massive gravity since its reference metric is assumed to be fully dynamical. In particular, the Einstein field equations along with the following constraint equations for both physical and reference metrics of a five-dimensional massive bigravity will be addressed. Then, we study some well-known cosmological spacetimes such as the Friedmann-Lemaitre-Robertson-Walker, Bianchi type I, and Schwarzschild-Tangherlini metrics for the five-dimensional massive bigravity. As a result, we find that massive graviton terms will serve as effective cosmological constants in both physical and reference sectors if a special scenario, in which reference metrics are chosen to be proportional to physical ones, is considered for all mentioned metrics. Thanks to the constancy property of massive graviton terms, consistent cosmological solutions will be figured out accordingly.

  13. The Simpson's paradox in quantum mechanics

    NASA Astrophysics Data System (ADS)

    Selvitella, Alessandro

    2017-03-01

    In probability and statistics, the Simpson's paradox is a paradox in which a trend that appears in different groups of data disappears when these groups are combined, while the reverse trend appears for the aggregate data. In this paper, we give some results about the occurrence of the Simpson's paradox in quantum mechanics. In particular, we prove that the Simpson's paradox occurs for solutions of the quantum harmonic oscillator both in the stationary case and in the non-stationary case. In the non-stationary case, the Simpson's paradox is persistent: if it occurs at any time t =t ˜ , then it occurs at any time t ≠t ˜ . Moreover, we prove that the Simpson's paradox is not an isolated phenomenon, namely, that, close to initial data for which it occurs, there are lots of initial data (a open neighborhood), for which it still occurs. Differently from the case of the quantum harmonic oscillator, we also prove that the paradox appears (asymptotically) in the context of the nonlinear Schrödinger equation but at intermittent times.

  14. Paradoxical Behavior of Granger Causality

    NASA Astrophysics Data System (ADS)

    Witt, Annette; Battaglia, Demian; Gail, Alexander

    2013-03-01

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

  15. Resolving thermoelectric "paradox" in superconductors.

    PubMed

    Shelly, Connor D; Matrozova, Ekaterina A; Petrashov, Victor T

    2016-02-01

    For almost a century, thermoelectricity in superconductors has been one of the most intriguing topics in physics. During its early stages in the 1920s, the mere existence of thermoelectric effects in superconductors was questioned. In 1944, it was demonstrated that the effects may occur in inhomogeneous superconductors. Theoretical breakthrough followed in the 1970s, when the generation of a measurable thermoelectric magnetic flux in superconducting loops was predicted; however, a major crisis developed when experiments showed puzzling discrepancies with the theory. Moreover, different experiments were inconsistent with each other. This led to a stalemate in bringing theory and experiment into agreement. With this work, we resolve this stalemate, thus solving this long-standing "paradox," and open prospects for exploration of novel thermoelectric phenomena predicted recently.

  16. The paradox of cooperation benefits.

    PubMed

    Németh, A; Takács, K

    2010-05-21

    It seems obvious that as the benefits of cooperation increase, the share of cooperators in the population should also increase. It is well known that positive assortment between cooperative types, for instance in spatially structured populations, provide better conditions for the evolution of cooperation than complete mixing. This study demonstrates that, assuming positive assortment, under most conditions higher cooperation benefits also increase the share of cooperators. On the other hand, under a specified range of payoff values, when at least two payoff parameters are modified, the reverse is true. The conditions for this paradox are determined for two-person social dilemmas: the Prisoner's Dilemma, the Hawks and Doves game, and the Stag Hunt game, assuming global selection and positive assortment.

  17. Cerebral emboli of paradoxical origin.

    PubMed

    Jones, H R; Caplan, L R; Come, P C; Swinton, N W; Breslin, D J

    1983-03-01

    A diagnosis of paradoxical cerebral embolus (PCE) was made in five patients aged 31 to 62 years who sustained eight cerebral ischemic events. No patient had evidence of primary carotid system or left heart disease. A probe-patent foramen ovale was the presumed mechanism in four patients, and an unsuspected congenital atrial septal defect was found in the fifth patient. Clinically apparent pulmonary emboli or venous thrombosis preceded the cerebral event in only one instance. Review of the literature reveals a high mortality with PCE. However, careful clinical search for this lesion may be rewarding: four of our five patients survived. One should consider PCE in any patient with cerebral embolus in whom there is no demonstrable left-sided circulatory source. This principle applies particularly if there is concomitant venous thrombosis, pulmonary embolism, or enhanced potential for venous thrombosis due to, for example, morbid obesity, use of hormonal birth control pills, prolonged bed rest (especially postoperatively), or systemic carcinoma.

  18. The moving plate capacitor paradox

    NASA Astrophysics Data System (ADS)

    Davis, B. R.; Abbott, D.; Parrondo, J. M. R.

    2000-03-01

    For the first time we describe an apparent paradox concerning a moving plate capacitor driven by thermal noise from a resistor. A demon restores the plates of the capacitor to their original position, only when the voltage across the capacitor is small—hence only small forces are present for the demon to work against. The demon has to work harder than this to avoid the situation of perpetual motion, but the question is how? We explore the concept of a moving plate capacitor, driven by noise, a step further by examining the case where the restoring force on the capacitor plates is provided by a simple spring, rather than some unknown demon. We display simulation results with interesting behavior, particularly where the capacitor plates collide with each other.

  19. Gray's paradox: A fluid mechanical perspective

    PubMed Central

    Bale, Rahul; Hao, Max; Bhalla, Amneet Pal Singh; Patel, Namrata; Patankar, Neelesh A.

    2014-01-01

    Nearly eighty years ago, Gray reported that the drag power experienced by a dolphin was larger than the estimated muscle power – this is termed as Gray's paradox. We provide a fluid mechanical perspective of this paradox. The viewpoint that swimmers necessarily spend muscle energy to overcome drag in the direction of swimming needs revision. For example, in undulatory swimming most of the muscle energy is directly expended to generate lateral undulations of the body, and the drag power is balanced not by the muscle power but by the thrust power. Depending on drag model utilized, the drag power may be greater than muscle power without being paradoxical. PMID:25082341

  20. Logistics of massive transfusions.

    PubMed

    DeLoughery, Thomas G

    2010-01-01

    Care of the patient with massive bleeding involves more than aggressive surgery and infusion of large amounts of blood products. The proper management of massive transfusions-whether they are in trauma patients or other bleeding patients-requires coordination of the personnel in the surgical suite or the emergency department, the blood bank, and laboratory.

  1. [Massive traumatic hemoptysis].

    PubMed

    Bourdereau, J M; Mathé, D; Voultoury, J C

    1985-01-01

    A case is reported of a patient who suffered a rupture of one lung as result of thoracic trauma. This gave rise to respiratory distress with massive haemoptysis which was initially treated with a double-lumen endotracheal tube, with separate lung ventilation, a chest drain and massive transfusion. A haemostatic pneumonectomy had to be performed because of the persisting and profuse bleeding.

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

    ERIC Educational Resources Information Center

    Gruber, Ronald P.; And Others

    1991-01-01

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

  3. Stokes paradox in electronic Fermi liquids

    NASA Astrophysics Data System (ADS)

    Lucas, Andrew

    2017-03-01

    The Stokes paradox is the statement that in a viscous two-dimensional fluid, the "linear response" problem of fluid flow around an obstacle is ill posed. We present a simple consequence of this paradox in the hydrodynamic regime of a Fermi liquid of electrons in two-dimensional metals. Using hydrodynamics and kinetic theory, we estimate the contribution of a single cylindrical obstacle to the global electrical resistance of a material, within linear response. Momentum relaxation, present in any realistic electron liquid, resolves the classical paradox. Nonetheless, this paradox imprints itself in the resistance, which can be parametrically larger than predicted by Ohmic transport theory. We find a remarkably rich set of behaviors, depending on whether or not the quasiparticle dynamics in the Fermi liquid should be treated as diffusive, hydrodynamic, or ballistic on the length scale of the obstacle. We argue that all three types of behavior are observable in present day experiments.

  4. Barrier paradox in the Klein zone

    SciTech Connect

    De Leo, Stefano; Rotelli, Pietro P.

    2006-04-15

    We study the solutions for a one-dimensional electrostatic potential in the Dirac equation when the incoming wave packet exhibits the Klein paradox (pair production). With a barrier potential we demonstrate the existence of multiple reflections (and transmissions). The antiparticle solutions which are necessarily localized within the barrier region create new pairs with each reflection at the potential walls. Consequently we encounter a new 'paradox' for the barrier because successive outgoing wave amplitudes grow geometrically.

  5. The Lindley paradox in optical interferometry

    NASA Astrophysics Data System (ADS)

    Mauri, Camillo; Paris, Matteo G. A.

    2016-02-01

    The so-called Lindley paradox is a counterintuitive statistical effect where the Bayesian and frequentist approaches to hypothesis testing give radically different answers, depending on the choice of the prior distribution. In this paper we address the occurrence of the Lindley paradox in optical interferometry and discuss its implications for high-precision measurements. In particular, we focus on phase estimation by Mach-Zehnder interferometers and show how to mitigate the conflict between the two approaches by using suitable priors.

  6. Johann Madler's Resolution of Olber's Paradox

    NASA Astrophysics Data System (ADS)

    Tipler, F. J.

    1988-09-01

    In 1861, some 40 years after Olbers' discussion of the paradox which bears his name, the German astronomer Johann Heinrich Mädler argued that a dark sky would be consistent with an infinite universe if the universe began a finite time in the past. The author shows that Mädler's resolution of Olbers' paradox is essentially the same as the resolution offered by modern cosmologists.

  7. The time–emotion paradox

    PubMed Central

    Droit-Volet, Sylvie; Gil, Sandrine

    2009-01-01

    The present manuscript discusses the time–emotion paradox in time psychology: although humans are able to accurately estimate time as if they possess a specific mechanism that allows them to measure time (i.e. an internal clock), their representations of time are easily distorted by the context. Indeed, our sense of time depends on intrinsic context, such as the emotional state, and on extrinsic context, such as the rhythm of others' activity. Existing studies on the relationships between emotion and time suggest that these contextual variations in subjective time do not result from the incorrect functioning of the internal clock but rather from the excellent ability of the internal clock to adapt to events in one's environment. Finally, the fact that we live and move in time and that everything, every act, takes more or less time has often been neglected. Thus, there is no unique, homogeneous time but instead multiple experiences of time. Our subjective temporal distortions directly reflect the way our brain and body adapt to these multiple time scales. PMID:19487196

  8. Unveiling the Mobile Learning Paradox.

    PubMed

    Mather, Carey; Cummings, Elizabeth

    2015-01-01

    A mobile learning paradox exists in Australian healthcare settings. Although it is increasingly acknowledged that timely, easy, and convenient access to health information using mobile learning technologies can enhance care and improve patient outcomes, currently there is an inability for nurses to access information at the point of care. Rapid growth in the use of mobile technology has created challenges for learning and teaching in the workplace. Easy access to educational resources via mobile devices challenges traditional strategies of knowledge and skill acquisition. Redesign of learning and teaching in the undergraduate curriculum and the development of policies to support the use of mobile learning at point of care is overdue. This study explored mobile learning opportunities used by clinical supervisors in tertiary and community-based facilities in two Australian States. Individual, organisation and systems level governance were sub-themes of professionalism that emerged as the main theme and impacts on learning and teaching in situ in healthcare environments. It is imperative healthcare work redesign includes learning and teaching that supports professional identity formation of students during work integrated learning.

  9. Protective effects of manganese, cobalt, nickel, and barium against a calcium paradox in the isolated frog heart.

    PubMed

    Touraki, M; Beis, I

    1991-09-01

    The effect of inorganic slow channel blockers on the calcium paradox in the frog heart was examined. Addition of the divalent cations of manganese, cobalt, nickel, or barium during calcium depletion protected the frog heart against a calcium paradox. This protective effect was indicated by reduced protein release, maintenance of electrical activity, and recovery of mechanical activity during reperfusion. Tissue calcium determination results showed that in the control paradox in the absence of divalent cations, there is an efflux of calcium from myocardial cells during calcium depletion and a massive influx of calcium during the following reperfusion, leading to a calcium overload. Divalent cations protected frog myocardial cells, when present in the calcium-free perfusion medium, by reducing both calcium efflux during calcium depletion and the massive calcium influx during reperfusion. The effectiveness of the added divalent cations showed a strong dependence upon their ionic radius. The most potent inhibitors of the calcium paradox in the frog heart were the divalent cations having an ionic radius closer to the ionic radius of calcium. These results are discussed in terms of the possible mechanism involved in the protective effect of manganese, cobalt, nickel, and barium.

  10. Law of the Minimum paradoxes.

    PubMed

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

    2011-09-01

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

  11. Retrocausation, Consistency, and the Bilking Paradox

    NASA Astrophysics Data System (ADS)

    Dobyns, York H.

    2011-11-01

    Retrocausation seems to admit of time paradoxes in which events prevent themselves from occurring and thereby create a physical instance of the liar's paradox, an event which occurs iff it does not occur. The specific version in which a retrocausal event is used to trigger an intervention which prevents its own future cause is called the bilking paradox (the event is bilked of its cause). The analysis of Echeverria, Klinkhammer, and Thorne (EKT) suggests time paradoxes cannot arise even in the presence of retrocausation. Any self-contradictory event sequence will be replaced in reality by a closely related but noncontradictory sequence. The EKT analysis implies that attempts to create bilking must instead produce logically consistent sequences wherein the bilked event arises from alternative causes. Bilking a retrocausal information channel of limited reliability usually results only in failures of signaling. An exception applies when the bilking is conducted in response only to some of the signal values that can be carried on the channel. Theoretical analysis based on EKT predicts that, since some of the channel outcomes are not bilked, the channel is capable of transmitting data with its normal reliability, and the paradox-avoidance effects will instead suppress the outcomes that would lead to forbidden (bilked) transmissions. A recent parapsychological experiment by Bem displays a retrocausal information channel of sufficient reliability to test this theoretical model of physical reality's response to retrocausal effects. A modified version with partial bilking would provide a direct test of the generality of the EKT mechanism.

  12. Use of informed consent with therapeutic paradox.

    PubMed

    Farkas, M M

    1992-01-01

    Debate persists in the literature and among clinicians about the ethical appropriateness of paradoxical interventions. It has been suggested that informed consent with therapeutic paradox would alleviate ethical concerns of deception, manipulation, harm to the client, and withholding of information from the client in therapy. The purpose of this study was to explore health care consumer reactions to the benefits and risks of therapeutic paradox as stated in a consent for treatment form. The study explored the responses of 32 medical patients to a hypothetical consent for treatment form for therapeutic paradox. Data were collected in a brief semistructured interview after subjects read the hypothetical consent form. Utilizing a case study, the investigator then offered an example of a successful paradoxical intervention and additional subject comments were solicited. Content analysis of the responses was made. Health care consumers had mixed responses to the consent form. While the consent form served as an obstacle for some consumers, many were willing to sign the consent form and accept treatment even though they had internal reservations and questions. Appropriateness of the consent form format is discussed.

  13. Paradoxical vocal cord motion--a case report.

    PubMed

    Lo, Hung-I; Ho, Hsu-Chueh; Hwang, Juen-Haur

    2005-12-01

    Paradoxical vocal cord motion (PVCM) is an unusual cause of stridor, which is associated with some underlying causes, such as central nervous system lesion, gastroesophageal reflux or psychogenic problem. Once a diagnosis of PVCM is made, acute management with reassurance and sedation instead of aggressive airway intervention is required. Speech therapy, psychotherapy combination with anti-reflux medication is considered to be useful in long-term management. We present a 58 year-old male patient who had suffered from several episodes of acute onset of stridor, short of breath and tachypnea since one year ago. He was initially treated as an asthmatic patient with poor response. Aneurysm of ascending aorta by angiography, and mild gastroesophageal reflux with hiatal hernia by panendoscopy were noted. Then, the paradoxical vocal cord motion during inspiration phase was confirmed by flexible fiberoptic nasopharyngoscope after the consultation with an otolaryngologist. The emergency of his air-hunger was relieved quickly after psychological intervention. Now, he is free of stridor attack under anti-reflux therapy and psychotherapy.

  14. Information-driven societies and Fermi's paradox

    NASA Astrophysics Data System (ADS)

    Lampton, Michael

    2013-10-01

    Fermi's paradox is founded on the idea that one or more Galactic extraterrestrial civilizations (ETCs) existed long ago and sustained exploration for millions of years, but in spite of their advanced knowledge, they could not find a way to explore the Galaxy other than with fleets of starships or self replicating probes. Here, I question this second assumption: if advanced technology generally allows long-distance remote sensing, and if ETCs were motivated by gaining information rather than conquest or commerce, then such voyages would be unnecessary, thereby resolving Fermi's paradox.

  15. Resummation of Massive Gravity

    SciTech Connect

    Rham, Claudia de; Gabadadze, Gregory; Tolley, Andrew J.

    2011-06-10

    We construct four-dimensional covariant nonlinear theories of massive gravity which are ghost-free in the decoupling limit to all orders. These theories resume explicitly all the nonlinear terms of an effective field theory of massive gravity. We show that away from the decoupling limit the Hamiltonian constraint is maintained at least up to and including quartic order in nonlinearities, hence excluding the possibility of the Boulware-Deser ghost up to this order. We also show that the same remains true to all orders in a similar toy model.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    ERIC Educational Resources Information Center

    Kristjansson, Kristjan

    2006-01-01

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

  18. Paradoxical pop-ups: Why are they difficult to catch?

    NASA Astrophysics Data System (ADS)

    McBeath, Michael K.; Nathan, Alan M.; Bahill, A. Terry; Baldwin, David G.

    2008-08-01

    Professional baseball players occasionally find it difficult to gracefully approach seemingly routine pop-ups. We describe a set of towering pop-ups with trajectories that exhibit cusps and loops near the apex. For a normal fly ball the horizontal velocity continuously decreases due to drag caused by air resistance. For pop-ups the Magnus force is larger than the drag force. In these cases the horizontal velocity initially decreases like a normal fly ball, but after the apex, the Magnus force accelerates the horizontal motion. We refer to this class of pop-ups as paradoxical because they appear to misinform the typically robust optical control strategies used by fielders and lead to systematic vacillation in running paths, especially when a trajectory terminates near the fielder. Former major league infielders confirm that our model agrees with their experiences.

  19. Massive and Open

    ERIC Educational Resources Information Center

    Fasimpaur, Karen

    2013-01-01

    MOOCs--massive open online courses--are all the rage these days, with hundreds of thousands of participants signing up and investors plunking down millions to get a piece of the pie. Why is there so much excitement about this new disruptive form of online learning, and how does this model apply to professional learning for teachers? Traditional…

  20. Massively Redundant Electromechanical Actuators

    DTIC Science & Technology

    2014-08-30

    date of determination). DoD Controlling Office is (insert controlling DoD office). "Massively Redundant Electromechanical Actuators" August... electromechanical systems) processes are used to manufacture reliable and reproducible stators and sliders for the actuators. These processes include

  1. Photosynthesis: the paradox of carbon dioxide efflux.

    PubMed

    Falkowski, P G

    1997-10-01

    The discovery that photosynthetic marine cyanobacteria can actually leak CO2 has been predicted from theory but, until now, never experimentally demonstrated. The apparent paradox can be explained by known chemistry and biochemistry, but the phenomenon may have important implications for paleoclimatology.

  2. Sustainable Development: Paradoxes, Misunderstandings and Learning Organizations

    ERIC Educational Resources Information Center

    Ramirez, Gabriel A.

    2012-01-01

    Purpose: Sustainability is, in itself, the idea of a harmonic answer to the dual nature of the most pressing problem for global society. Most of the problems dealing with sustainability concern its dual and contradictory nature. That paradoxical reality is in no way a unique feature of sustainability; its universal pervasiveness is demonstrated by…

  3. Twin Paradox in de Sitter Spacetime

    ERIC Educational Resources Information Center

    Boblest, Sebastian; Muller, Thomas; Wunner, Gunter

    2011-01-01

    The "twin paradox" of special relativity offers the possibility of making interstellar flights within a lifetime. For very long journeys with velocities close to the speed of light, however, we have to take into account the expansion of the universe. Inspired by the work of Rindler on hyperbolic motion in curved spacetime, we study the worldline…

  4. NEW APPROACHES: The twins paradox explained

    NASA Astrophysics Data System (ADS)

    Linton, J. O.

    1997-09-01

    The well-known paradox of the space-travelling twins is easily stated, but it is not at all easy to explain, especially to a perspicacious audience. This essay attempts to set out an explanation (largely inspired by Paul Davies' book About Time [1]) which should be within the grasp of an intelligent sixth-former.

  5. An alternative resolution to the Mansuripur paradox

    NASA Astrophysics Data System (ADS)

    Redfern, Francis

    2016-04-01

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

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

    ERIC Educational Resources Information Center

    Isaac, Barry L.

    1974-01-01

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

  7. The Sustainability Solution To The Fermi Paradox

    NASA Astrophysics Data System (ADS)

    Haqq-Misra, J. D.; Baum, S. D.

    No present observations suggest a technologically advanced extraterrestrial intelligence (ETI) has spread through the galaxy. However, under commonplace assumptions about galactic civilization formation and expansion, this absence of observation is highly unlikely. This improbability is the heart of the Fermi Paradox. The Fermi Paradox leads some to conclude that humans have the only advanced civilization in this galaxy, either because civilization formation is very rare or because intelligent civilizations inevitably destroy themselves. In this paper, we argue that this conclusion is premature by introducing the “Sustainability Solution” to the Fermi Paradox, which questions the Paradox's assumption of faster ( e.g. exponential) civilization growth. Drawing on insights from the sustainability of human civilization on Earth, we propose that faster-growth may not be sustainable on the galactic scale. If this is the case, then there may exist ETI that have not expanded throughout the galaxy or have done so but collapsed. These possibilities have implications for both searches for ETI and for human civilization management.

  8. Toward a Theory of Coaching Paradox

    ERIC Educational Resources Information Center

    Barnson, Steven C.

    2014-01-01

    Multiple tensions exist as part of the coaching process. How a coach responds to these tensions is a fundamental determinant of an athlete or team's fate. In today's highly competitive, socially demanding, and ever-changing sports environment, and as the expectations on coaches become more complex, the paradox becomes a critical lens to…

  9. Consistent resolution of some relativistic quantum paradoxes

    SciTech Connect

    Griffiths, Robert B.

    2002-12-01

    A relativistic version of the (consistent or decoherent) histories approach to quantum theory is developed on the basis of earlier work by Hartle, and used to discuss relativistic forms of the paradoxes of spherical wave packet collapse, Bohm's formulation of the Einstein-Podolsky-Rosen paradox, and Hardy's paradox. It is argued that wave function collapse is not needed for introducing probabilities into relativistic quantum mechanics, and in any case should never be thought of as a physical process. Alternative approaches to stochastic time dependence can be used to construct a physical picture of the measurement process that is less misleading than collapse models. In particular, one can employ a coarse-grained but fully quantum-mechanical description in which particles move along trajectories, with behavior under Lorentz transformations the same as in classical relativistic physics, and detectors are triggered by particles reaching them along such trajectories. States entangled between spacelike separate regions are also legitimate quantum descriptions, and can be consistently handled by the formalism presented here. The paradoxes in question arise because of using modes of reasoning which, while correct for classical physics, are inconsistent with the mathematical structure of quantum theory, and are resolved (or tamed) by using a proper quantum analysis. In particular, there is no need to invoke, nor any evidence for, mysterious long-range superluminal influences, and thus no incompatibility, at least from this source, between relativity theory and quantum mechanics.

  10. A Developmental Perspective on the Imperfective Paradox

    ERIC Educational Resources Information Center

    Kazanina, Nina; Phillips, Colin

    2007-01-01

    Imperfective or progressive verb morphology makes it possible to use the name of a whole event to refer to an activity that is clearly not a complete instance of that event, leading to what is known as the Imperfective Paradox. For example, a sentence like "John was building a house" does not entail that a house ever got built. The Imperfective…

  11. Amphetamine's Paradoxical Effects May Be Predictable

    ERIC Educational Resources Information Center

    Zentall, Sydney S.; Zentall, Thomas R.

    1976-01-01

    It is suggested that the so-called paradoxical calming or depressant effects of amphetamine on hyperactive children can be accounted for by the proposition that amphetamines increase arousal when the initial arousal level is low but decrease arousal when the initial level is high. (Author)

  12. Art's Pedagogical Paradox

    ERIC Educational Resources Information Center

    Kalin, Nadine M.

    2014-01-01

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

  13. Bell's Paradox under Different Capital Market Regimes.

    ERIC Educational Resources Information Center

    Kang, Johan Moonwon

    1993-01-01

    In 1984 "Economics of Education Review" paper, E. Bell indicates that, when capital markets are imperfect in a certain sense, demand for education may not always be directly related with present net value of education. This study shows Bell's paradox is possible under the alternative definitions of capital market imperfections and…

  14. Massively Parallel Genetics.

    PubMed

    Shendure, Jay; Fields, Stanley

    2016-06-01

    Human genetics has historically depended on the identification of individuals whose natural genetic variation underlies an observable trait or disease risk. Here we argue that new technologies now augment this historical approach by allowing the use of massively parallel assays in model systems to measure the functional effects of genetic variation in many human genes. These studies will help establish the disease risk of both observed and potential genetic variants and to overcome the problem of "variants of uncertain significance."

  15. New improved massive gravity

    NASA Astrophysics Data System (ADS)

    Dereli, T.; Yetişmişoğlu, C.

    2016-06-01

    We derive the field equations for topologically massive gravity coupled with the most general quadratic curvature terms using the language of exterior differential forms and a first-order constrained variational principle. We find variational field equations both in the presence and absence of torsion. We then show that spaces of constant negative curvature (i.e. the anti de-Sitter space AdS 3) and constant torsion provide exact solutions.

  16. A Resolution of the Paradox of Enrichment

    NASA Astrophysics Data System (ADS)

    Feng, Z. C.; Li, Y. Charles

    2015-06-01

    The paradox of enrichment was observed by Rosenzweig [1971] in a class of predator-prey models. Two of the parameters in the models are crucial for the paradox. These two parameters are the prey's carrying capacity and prey's half-saturation for predation. Intuitively, increasing the carrying capacity due to enrichment of the prey's environment should lead to a more stable predator-prey system. Analytically, it turns out that increasing the carrying capacity always leads to an unstable predator-prey system that is susceptible to extinction from environmental random perturbations. This is the so-called paradox of enrichment. Our resolution here rests upon a closer investigation on a dimensionless number H formed from the carrying capacity and the prey's half-saturation. By recasting the models into dimensionless forms, the models are in fact governed by a few dimensionless numbers including H. The effects of the two parameters: carrying capacity and half-saturation are incorporated into the number H. In fact, increasing the carrying capacity is equivalent (i.e. has the same effect on H) to decreasing the half-saturation which implies more aggressive predation. Since there is no paradox between more aggressive predation and instability of the predator-prey system, the paradox of enrichment is resolved. The so-called instability of the predator-prey system is characterized by the existence of a stable limit cycle in the phase plane, which gets closer and closer to the predator axis and prey axis. Due to random environmental perturbations, this can lead to extinction. We also further explore spatially dependent models for which the phase space is infinite-dimensional. The spatially independent limit cycle which is generated by a Hopf bifurcation from an unstable steady state, is linearly stable in the infinite-dimensional phase space. Numerical simulations indicate that the basin of attraction of the limit cycle is riddled. This shows that spatial perturbations can

  17. Phases of massive gravity

    NASA Astrophysics Data System (ADS)

    Dubovsky, Sergei L.

    2004-10-01

    We systematically study the most general Lorentz-violating graviton mass invariant under three-dimensional Eucledian group. We find that at general values of mass parameters the massive graviton has six propagating degrees of freedom, and some of them are ghosts or lead to rapid classical instabilities. However, there is a number of different regions in the mass parameter space where massive gravity is described by a consistent low-energy effective theory with cutoff ~ (mMPl)1/2. This theory is free of rapid instabilities and vDVZ discontinuity. Each of these regions is characterized by certain fine-tuning relations between mass parameters, generalizing the Fierz Pauli condition. In some cases the required fine-tunings are consequences of the existence of the subgroups of the diffeomorphism group that are left unbroken by the graviton mass. We found two new cases, when the resulting theories have a property of UV insensitivity, i.e. remain well behaved after inclusion of arbitrary higher dimension operators without assuming any fine-tunings among the coefficients of these operators, besides those enforced by the symmetries. These theories can be thought of as generalizations of the ghost condensate model with a smaller residual symmetry group. We briefly discuss what kind of cosmology can one expect in massive gravity and argue that the allowed values of the graviton mass may be quite large, affecting growth of primordial perturbations, structure formation and, perhaps, enhancing the backreaction of inhomogeneities on the expansion rate of the Universe.

  18. Hardy's paradox and measurement-disturbance relations

    NASA Astrophysics Data System (ADS)

    Fujikawa, Kazuo; Oh, C. H.; Yu, Sixia

    2015-01-01

    We establish a quantitative relation between Hardy's paradox and the breaking of the uncertainty principle in the sense of measurement-disturbance relations in the conditional measurement of noncommuting operators. The analysis of the inconsistency of local realism with entanglement by Hardy is simplified if this breaking of measurement-disturbance relations is taken into account, and a much simplified experimental test of local realism is illustrated in the framework of Hardy's thought experiment. The essence of Hardy's model is identified as a combination of two conditional measurements, which give rise to definite eigenvalues to two noncommuting operators simultaneously in hidden-variables models. Better understanding of the intimate interplay of entanglement and measurement disturbance is crucial in the current discussions of Hardy's paradox using the idea of weak measurement, which is based on a general analysis of measurement-disturbance relations.

  19. Osteoporosis: a paradox in ankylosing spondylitis.

    PubMed

    Carter, Shea; Lories, Rik J

    2011-09-01

    Ankylosing spondylitis is a chronic and severe inflammatory disease of the axial skeleton and the joints. Inflammation is associated with trabecular bone loss leading to osteoporosis but also with corcal new bone formation leading to progressive ankylosis of the spine and sacroiliac joints. This results in an apparent paradox of bone formation and loss taking place at sites closesly located to each other. Osteoporosis can be explained by the impact of inflammation of the bone remodeling cycle. In contrast, new bone formation has been linked to aberrant acvaon of bone morphogenec protein and Wnt signaling. In this commentary, we review recent data on this bone paradox and highlight recent advances including the effect of current drug therapies and the idenfication of new therapeutic targets.

  20. A Canadian paradox: Tommy Douglas and eugenics.

    PubMed

    Shevell, Michael

    2012-01-01

    Tommy Douglas is an icon of Canadian 20th Century political history and is considered by many as the "Father" of Medicare, a key component of our national identity. Throughout his career, he was associated at both the provincial and federal levels with progressive causes concerning disadvantaged populations. In his sociology Master's thesis written in the early 1930's, Douglas endorsed eugenic oriented solutions such as segregation and sterilization to address what was perceived to be an endemic and biologically determined problem. At first glance, this endorsement of eugenics appears to be paradoxical, but careful analysis revealed that this paradox has multiple roots in religion, political belief, historical exposure and our own desire to view our collective history in a favourable light.

  1. The happiness-income paradox revisited.

    PubMed

    Easterlin, Richard A; McVey, Laura Angelescu; Switek, Malgorzata; Sawangfa, Onnicha; Zweig, Jacqueline Smith

    2010-12-28

    The striking thing about the happiness-income paradox is that over the long-term--usually a period of 10 y or more--happiness does not increase as a country's income rises. Heretofore the evidence for this was limited to developed countries. This article presents evidence that the long term nil relationship between happiness and income holds also for a number of developing countries, the eastern European countries transitioning from socialism to capitalism, and an even wider sample of developed countries than previously studied. It also finds that in the short-term in all three groups of countries, happiness and income go together, i.e., happiness tends to fall in economic contractions and rise in expansions. Recent critiques of the paradox, claiming the time series relationship between happiness and income is positive, are the result either of a statistical artifact or a confusion of the short-term relationship with the long-term one.

  2. The Island Wind-Buoyancy Paradox

    NASA Astrophysics Data System (ADS)

    de Boer, A. M.; Nof, D.

    2003-04-01

    In recent years, a variety of studies have suggested that the meridional overturning circulation is at least partially controlled by the Southern Ocean winds. However, the overturning requires transformation of water masses, a process driven by buoyancy fluxes. This seems paradoxical as the wind and buoyancy fluxes are generally thought to be independent. The paradox is resolved qualitatively, using salinity and temperature mixed dynamical-box models, and quantitatively, employing a numerical model. The salinity and temperature box models suggest that stronger southern winds will tend to weaken the vertical and horizontal salinity stratification so that it is easier for the conversion of deep to surface water (and vice versa) to take place. The (process-orientated) reduced-gravity numerical model is adapted to include a thermodynamic parameterization for the surface heat and freshwater fluxes. In response to stronger southern winds, the thermocline thickens in the north, releasing more heat to the atmosphere and, thereby, converting more surface to deep water.

  3. "Permanence" - An Adaptationist Solution to Fermi's Paradox?

    NASA Astrophysics Data System (ADS)

    Cirkovic, Milan M.

    A new solution of Fermi's paradox sketched by SF writer Karl Schroeder in his 2002. novel Permanence is investigated. It is argued that this solution is tightly connected with adaptationism - a widely discussed working hypothesis in evolutionary biology. Schroeder's hypothesis has important ramifications for astrobiology, SETI projects, and future studies. Its weaknesses should be explored without succumbing to the emotional reactions often accompanying adaptationist explanations.

  4. Paradoxical insomnia in a patient taking zopiclone.

    PubMed

    Abba-Aji, Adam; Bardoloi, Prajjita

    2017-01-19

    We present a case of a man aged 20 years who was diagnosed with a major depressive disorder and was started on escitalopram and zopiclone. The patient had a significant response to escitalopram except that he developed severe insomnia which dramatically resolved following discontinuation of zopiclone. The patient was recommenced on low dose of zopiclone and unfortunately redeveloped moderate insomnia. The patient was thoroughly investigated and zopiclone was determined to have paradoxically caused the insomnia.

  5. Enjoying Sad Music: Paradox or Parallel Processes?

    PubMed

    Schubert, Emery

    2016-01-01

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

  6. Enjoying Sad Music: Paradox or Parallel Processes?

    PubMed Central

    Schubert, Emery

    2016-01-01

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

  7. A developmental perspective on the Imperfective Paradox.

    PubMed

    Kazanina, Nina; Phillips, Colin

    2007-10-01

    Imperfective or progressive verb morphology makes it possible to use the name of a whole event to refer to an activity that is clearly not a complete instance of that event, leading to what is known as the Imperfective Paradox. For example, a sentence like 'John was building a house' does not entail that a house ever got built. The Imperfective Paradox has received a number of different treatments in the philosophical and linguistic literature, but has received less attention from the perspective of language acquisition. This article presents developmental evidence on the nature of the Imperfective Paradox, based on a series of four experiments conducted with Russian-speaking 3 to 6 year olds. Despite the fact that Russian is a language in which the morphological form of imperfectives is highly salient and used appropriately at a very young age, younger children show a clearly non-adultlike pattern of comprehension in our experiments. The results from Experiments 1 and 2 suggest that Russian-speaking children incorrectly ascribe completion entailments to imperfectives. However, Experiments 3 and 4 indicate that the children recognize that imperfectives can describe incomplete events, and that their problem instead concerns their inability to find a suitable temporal interval against which to evaluate imperfective statements. Specifically, children are only willing to accept an imperfective predicate as a description of a past incomplete event when the sentence contains an explicit temporal modifier that highlights a time interval that ends before the failure point of the event. These findings are taken as support for an account of the imperfective that makes use of temporal perspectives in solving the Imperfective Paradox.

  8. Identifying Quantum Structures in the Ellsberg Paradox

    NASA Astrophysics Data System (ADS)

    Aerts, Diederik; Sozzo, Sandro; Tapia, Jocelyn

    2014-10-01

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

  9. Obesity and poverty paradox in developed countries.

    PubMed

    Żukiewicz-Sobczak, Wioletta; Wróblewska, Paula; Zwoliński, Jacek; Chmielewska-Badora, Jolanta; Adamczuk, Piotr; Krasowska, Ewelina; Zagórski, Jerzy; Oniszczuk, Anna; Piątek, Jacek; Silny, Wojciech

    2014-01-01

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

  10. A Probabilistic Analysis of the Fermi Paradox

    NASA Astrophysics Data System (ADS)

    Solomonides, Evan; Terzian, Yervant

    2016-06-01

    The Fermi paradox uses an appeal to the mediocrity principle to make it seem counterintuitive that humanity has not been contacted by extraterrestrial intelligence. A numerical, statistical analysis was conducted to determine whether this apparent loneliness is, in fact, unexpected. An inequality was derived to relate the frequency of life arising and developing technology on a suitable planet in the galaxy; the average length of time since the first broadcast of such a civilization; and a constant term. An analysis of the sphere reached thus far by human communication was also conducted, considering our local neighborhood and planets of particular interest. These analyses both conclude that the Fermi paradox is not, in fact, unexpected. By the mediocrity principle and numerical modeling, it is actually unlikely that the Earth would have been reached by extraterrestrial communication at this point. We predict that under 1% of the galaxy has been reached at all thus far, and we do not anticipate to be reached until approximately 50% of stars/planets have been reached. We offer a prediction that we should not expect this until at least 1,500 years in the future. Thus the Fermi paradox is not a shocking observation- or lack thereof- and humanity may very well be contacted within our species’ lifespan (we can begin to expect to be contacted 1,500 years in the future).

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

    NASA Astrophysics Data System (ADS)

    Cirkovic, M. M.

    2009-06-01

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

  12. Hawking radiation and the boomerang behavior of massive modes near a horizon

    SciTech Connect

    Jannes, G.; Maiessa, P.; Rousseaux, G.; Philbin, T. G.

    2011-05-15

    We discuss the behavior of massive modes near a horizon based on a study of the dispersion relation and wave packet simulations of the Klein-Gordon equation. We point out an apparent paradox between two (in principle equivalent) pictures of black-hole evaporation through Hawking radiation. In the picture in which the evaporation is due to the emission of positive-energy modes, one immediately obtains a threshold for the emission of massive particles. In the picture in which the evaporation is due to the absorption of negative-energy modes, such a threshold apparently does not exist. We resolve this paradox by tracing the evolution of the positive-energy massive modes with an energy below the threshold. These are seen to be emitted and move away from the black-hole horizon, but they bounce back at a 'red horizon' and are reabsorbed by the black hole, thus compensating exactly for the difference between the two pictures. For astrophysical black holes, the consequences are curious but do not affect the terrestrial constraints on observing Hawking radiation. For analogue-gravity systems with massive modes, however, the consequences are crucial and rather surprising.

  13. Paradoxical Herniation following Decompressive Craniectomy in the Subacute Setting

    PubMed Central

    Espinosa, Jose

    2016-01-01

    Decompressive craniectomy is reserved for extreme cases of intracranial hypertension. An uncommon complication known as paradoxical herniation has been documented within weeks to months following surgery. Here we present a unique case within days of surgery. Since standard medical treatment for intracranial hypertension will exacerbate paradoxical herniation, any abrupt neurological changes following decompressive craniectomy should be carefully investigated. Immediate treatment for paradoxical herniation is placement of the patient in the supine position with adequate hydration. Cranioplasty is the ultimate treatment option. PMID:27446619

  14. On the equivalence of Goodman's and Hempel's paradoxes.

    PubMed

    Boyce, Kenneth

    2014-03-01

    Historically, Nelson Goodman's paradox involving the predicates 'grue' and 'bleen' has been taken to furnish a serious blow to Carl Hempel's theory of confirmation in particular and to purely formal theories of confirmation in general. In this paper, I argue that Goodman's paradox is no more serious of a threat to Hempel's theory of confirmation than is Hempel's own paradox of the ravens. I proceed by developing a suggestion from R. D. Rosenkrantz into an argument for the conclusion that these paradoxes are, in fact, equivalent. My argument, if successful, is of both historical and philosophical interest. Goodman himself maintained that Hempel's theory of confirmation was capable of handling the paradox of the ravens. And Hempel eventually conceded that Goodman's paradox showed that there could be no adequate, purely syntactical theory of confirmation. The conclusion of my argument entails, by contrast, that Hempel's theory of confirmation is incapable of handling Goodman's paradox if and only if it is incapable of handling the paradox of the ravens. It also entails that for any adequate solution to one of these paradoxes, there is a corresponding and equally adequate solution to the other.

  15. Inconsistency of topologically massive hypergravity

    NASA Technical Reports Server (NTRS)

    Aragone, C.; Deser, S.

    1985-01-01

    The coupled topologically massive spin-5/2 gravity system in D = 3 dimensions whose kinematics represents dynamical propagating gauge invariant massive spin-5/2 and spin-2 excitations, is shown to be inconsistent, or equivalently, not locally hypersymmetric. In contrast to D = 4, the local constraints on the system arising from failure of the fermionic Bianchi identities do not involve the 'highest spin' components of the field, but rather the auxiliary spinor required to construct a consistent massive model.

  16. Minimal massive 3D gravity

    NASA Astrophysics Data System (ADS)

    Bergshoeff, Eric; Hohm, Olaf; Merbis, Wout; Routh, Alasdair J.; Townsend, Paul K.

    2014-07-01

    We present an alternative to topologically massive gravity (TMG) with the same ‘minimal’ bulk properties; i.e. a single local degree of freedom that is realized as a massive graviton in linearization about an anti-de Sitter (AdS) vacuum. However, in contrast to TMG, the new ‘minimal massive gravity’ has both a positive energy graviton and positive central charges for the asymptotic AdS-boundary conformal algebra.

  17. Vitamin paradox in obesity: Deficiency or excess?

    PubMed Central

    Zhou, Shi-Sheng; Li, Da; Chen, Na-Na; Zhou, Yiming

    2015-01-01

    Since synthetic vitamins were used to fortify food and as supplements in the late 1930s, vitamin intake has significantly increased. This has been accompanied by an increased prevalence of obesity, a condition associated with diabetes, hypertension, cardiovascular disease, asthma and cancer. Paradoxically, obesity is often associated with low levels of fasting serum vitamins, such as folate and vitamin D. Recent studies on folic acid fortification have revealed another paradoxical phenomenon: obesity exhibits low fasting serum but high erythrocyte folate concentrations, with high levels of serum folate oxidation products. High erythrocyte folate status is known to reflect long-term excess folic acid intake, while increased folate oxidation products suggest an increased folate degradation because obesity shows an increased activity of cytochrome P450 2E1, a monooxygenase enzyme that can use folic acid as a substrate. There is also evidence that obesity increases niacin degradation, manifested by increased activity/expression of niacin-degrading enzymes and high levels of niacin metabolites. Moreover, obesity most commonly occurs in those with a low excretory reserve capacity (e.g., due to low birth weight/preterm birth) and/or a low sweat gland activity (black race and physical inactivity). These lines of evidence raise the possibility that low fasting serum vitamin status in obesity may be a compensatory response to chronic excess vitamin intake, rather than vitamin deficiency, and that obesity could be one of the manifestations of chronic vitamin poisoning. In this article, we discuss vitamin paradox in obesity from the perspective of vitamin homeostasis. PMID:26322161

  18. Seventy Years of the EPR Paradox

    NASA Astrophysics Data System (ADS)

    Kupczynski, Marian

    2006-11-01

    In spite of the fact that statistical predictions of quantum theory (QT) can only be tested if large amount of data is available a claim has been made that QT provides the most complete description of an individual physical system. Einstein's opposition to this claim and the paradox he presented in the article written together with Podolsky and Rosen in 1935 inspired generations of physicists in their quest for better understanding of QT. Seventy years after EPR article it is clear that without deep understanding of the character and limitations of QT one may not hope to find a meaningful unified theory of all physical interactions, manipulate qubits or construct a quantum computer.. In this paper we present shortly the EPR paper, the discussion, which followed it and Bell inequalities (BI). To avoid various paradoxes we advocate purely statistical contextual interpretation (PSC) of QT. According to PSC a state vector is not an attribute of a single electron, photon, trapped ion or quantum dot. A value of an observable assigned to a physical system has only a meaning in a context of a particular physical experiment PSC does not provide any mental space-time picture of sub phenomena. The EPR paradox is avoided because the reduction of the state vector in the measurement process is a passage from a description of the whole ensemble of the experimental results to a particular sub-ensemble of these results. We show that the violation of BI is neither a proof of the completeness of QT nor of its non-locality. Therefore we rephrase the EPR question and ask whether QT is "predictably "complete or in other words does it provide the complete description of experimental data. To test the "predictable completeness" it is not necessary to perform additional experiments it is sufficient to analyze more in detail the existing experimental data by using various non-parametric purity tests and other specific statistical tools invented to study the fine structure the time-series.

  19. Vitamin paradox in obesity: Deficiency or excess?

    PubMed

    Zhou, Shi-Sheng; Li, Da; Chen, Na-Na; Zhou, Yiming

    2015-08-25

    Since synthetic vitamins were used to fortify food and as supplements in the late 1930s, vitamin intake has significantly increased. This has been accompanied by an increased prevalence of obesity, a condition associated with diabetes, hypertension, cardiovascular disease, asthma and cancer. Paradoxically, obesity is often associated with low levels of fasting serum vitamins, such as folate and vitamin D. Recent studies on folic acid fortification have revealed another paradoxical phenomenon: obesity exhibits low fasting serum but high erythrocyte folate concentrations, with high levels of serum folate oxidation products. High erythrocyte folate status is known to reflect long-term excess folic acid intake, while increased folate oxidation products suggest an increased folate degradation because obesity shows an increased activity of cytochrome P450 2E1, a monooxygenase enzyme that can use folic acid as a substrate. There is also evidence that obesity increases niacin degradation, manifested by increased activity/expression of niacin-degrading enzymes and high levels of niacin metabolites. Moreover, obesity most commonly occurs in those with a low excretory reserve capacity (e.g., due to low birth weight/preterm birth) and/or a low sweat gland activity (black race and physical inactivity). These lines of evidence raise the possibility that low fasting serum vitamin status in obesity may be a compensatory response to chronic excess vitamin intake, rather than vitamin deficiency, and that obesity could be one of the manifestations of chronic vitamin poisoning. In this article, we discuss vitamin paradox in obesity from the perspective of vitamin homeostasis.

  20. The paradox of strategic environmental assessment

    SciTech Connect

    Bidstrup, Morten Hansen, Anne Merrild

    2014-07-01

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

  1. Massively parallel mathematical sieves

    SciTech Connect

    Montry, G.R.

    1989-01-01

    The Sieve of Eratosthenes is a well-known algorithm for finding all prime numbers in a given subset of integers. A parallel version of the Sieve is described that produces computational speedups over 800 on a hypercube with 1,024 processing elements for problems of fixed size. Computational speedups as high as 980 are achieved when the problem size per processor is fixed. The method of parallelization generalizes to other sieves and will be efficient on any ensemble architecture. We investigate two highly parallel sieves using scattered decomposition and compare their performance on a hypercube multiprocessor. A comparison of different parallelization techniques for the sieve illustrates the trade-offs necessary in the design and implementation of massively parallel algorithms for large ensemble computers.

  2. Paradox of integration-A computational model

    NASA Astrophysics Data System (ADS)

    Krawczyk, Małgorzata J.; Kułakowski, Krzysztof

    2017-02-01

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

  3. Feynman's Relativistic Electrodynamics Paradox and the Aharonov-Bohm Effect

    NASA Astrophysics Data System (ADS)

    Caprez, Adam; Batelaan, Herman

    2009-03-01

    An analysis is done of a relativistic paradox posed in the Feynman Lectures of Physics involving two interacting charges. The physical system presented is compared with similar systems that also lead to relativistic paradoxes. The momentum conservation problem for these systems is presented. The relation between the presented analysis and the ongoing debates on momentum conservation in the Aharonov-Bohm problem is discussed.

  4. Leaves and Foxes: Using Hyperbole and Paradox in Poetry.

    ERIC Educational Resources Information Center

    DePoy, Phillip

    1997-01-01

    Presents a three-part exercise that deals with poetic excess: heightened exaggeration of deliberately conflicting ideas. States that part 1 deals with hyperbole, part 2 with paradox, and part 3 with combining hyperbole and paradox in a single poem. Gives examples of students' poems using the technique. (PA)

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

    ERIC Educational Resources Information Center

    Bacon, Stephen Barcia

    Paradox and therapeutic double bind techniques are used to overcome resistance in students with a history of success avoidance. Predictions of failure, restraining comments, and the use of paradox in the midst of an activity are defended theoretically by presenting historical roots and a rationale of effectiveness. A skill-building approach…

  6. Bolzano's Approach to the Paradoxes of Infinity: Implications for Teaching

    ERIC Educational Resources Information Center

    Waldegg, Guillermina

    2005-01-01

    In this paper we analyze excerpts of "Paradoxes of the Infinite", the posthumous work of Bernard Bolzano (1781-1848), in order to show that Georg Cantor's (1845-1918) approach to the problem of defining actual mathematical infinity is not the most natural. In fact, Bolzano's approach to the paradoxes of infinity is more intuitive, while remaining…

  7. A Simple Explanation of the Classic Hydrostatic Paradox

    ERIC Educational Resources Information Center

    Kontomaris, Stylianos-Vasileios; Malamou, Anna

    2016-01-01

    An interesting problem in fluid mechanics, with significant educational importance, is the classic hydrostatic paradox. The hydrostatic paradox states the fact that in different shaped containers, with the same base area, which are filled with a liquid of the same height, the applied force by the liquid on the base of each container is exactly the…

  8. Killing Mosquitoes and Keeping Practice: Teacher Education as Sustaining Paradox

    ERIC Educational Resources Information Center

    Keiser, David Lee

    2013-01-01

    The moral and ethical charge of teaching and teacher education includes sustaining equanimity and paradox, and maintaining poise amongst contradicting policies and interests. This paper draws upon the wisdom of the Tao Te Ching to address some paradoxes in education and teacher preparation. Specifically, the article looks at four chapters of the…

  9. Paradoxical Double Binds in Human-Relations Training.

    ERIC Educational Resources Information Center

    Becvar, Raphael J.

    1978-01-01

    Paradoxical double binds are discussed relative to their efficacy in helping systematic human-relations trainees integrate the skills more quickly and with less pain and frustration. An explanation and examples of paradoxical double binds used in human-relations training are presented. (Author)

  10. Two Paradoxes of the "Seller's Market" of Chinese Higher Education

    ERIC Educational Resources Information Center

    Huang, J.

    2005-01-01

    In recent years, two "paradoxes" have emerged in the "seller's market" of Chinese higher education. One is a strong demand for buying educational services and a weak demand for consumption; a second is the coexistence of an entry to the seller's market and an exit point from the buyer's market. These two "paradoxes"…

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

    ERIC Educational Resources Information Center

    Woelert, Peter; Millar, Victoria

    2013-01-01

    This paper identifies what can be called the "paradox of interdisciplinarity" (Weingart 2000) in Australian higher education research governance and explores some of its constitutive dimensions. In the Australian context, the paradox of interdisciplinarity primarily concerns the proliferation of a programmatic discourse of…

  12. The evolution of massive stars

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The hypotheses underlying theoretical studies of the evolution of massive model stars with and without mass loss are summarized. The evolutionary tracks followed by the models across theoretical Hertzsprung-Russell (HR) diagrams are compared with the observed distribution of B stars in an HR diagram. The pulsational properties of models of massive star are also described.

  13. The oxygen paradox of neurovascular coupling

    PubMed Central

    Leithner, Christoph; Royl, Georg

    2014-01-01

    The coupling of cerebral blood flow (CBF) to neuronal activity is well preserved during evolution. Upon changes in the neuronal activity, an incompletely understood coupling mechanism regulates diameter changes of supplying blood vessels, which adjust CBF within seconds. The physiologic brain tissue oxygen content would sustain unimpeded brain function for only 1 second if continuous oxygen supply would suddenly stop. This suggests that the CBF response has evolved to balance oxygen supply and demand. Surprisingly, CBF increases surpass the accompanying increases of cerebral metabolic rate of oxygen (CMRO2). However, a disproportionate CBF increase may be required to increase the concentration gradient from capillary to tissue that drives oxygen delivery. However, the brain tissue oxygen content is not zero, and tissue pO2 decreases could serve to increase oxygen delivery without a CBF increase. Experimental evidence suggests that CMRO2 can increase with constant CBF within limits and decreases of baseline CBF were observed with constant CMRO2. This conflicting evidence may be viewed as an oxygen paradox of neurovascular coupling. As a possible solution for this paradox, we hypothesize that the CBF response has evolved to safeguard brain function in situations of moderate pathophysiological interference with oxygen supply. PMID:24149931

  14. Unveiling consumer's privacy paradox behaviour in an economic exchange.

    PubMed

    Motiwalla, Luvai F; Li, Xiao-Bai

    2016-01-01

    Privacy paradox is of great interest to IS researchers and firms gathering personal information. It has been studied from social, behavioural, and economic perspectives independently. However, prior research has not examined the degrees of influence these perspectives contribute to the privacy paradox problem. We combine both economic and behavioural perspectives in our study of the privacy paradox with a price valuation of personal information through an economic experiment combined with a behavioural study on privacy paradox. Our goal is to reveal more insights on the privacy paradox through economic valuation on personal information. Results indicate that general privacy concerns or individual disclosure concerns do not have a significant influence on the price valuation of personal information. Instead, prior disclosure behaviour in specific scenario, like with healthcare providers or social networks, is a better indicator of consumer price valuations.

  15. ASA's Chandra Neon Discovery Solves Solar Paradox

    NASA Astrophysics Data System (ADS)

    2005-07-01

    NASA's Chandra X-ray Observatory survey of nearby sun-like stars suggests there is nearly three times more neon in the sun and local universe than previously believed. If true, this would solve a critical problem with understanding how the sun works. "We use the sun to test how well we understand stars and, to some extent, the rest of the universe," said Jeremy Drake of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. "But in order to understand the sun, we need to know exactly what it is made of," he added. It is not well known how much neon the sun contains. This is critical information for creating theoretical models of the sun. Neon atoms, along with carbon, oxygen and nitrogen, play an important role in how quickly energy flows from nuclear reactions in the sun's core to its edge, where it then radiates into space. Chandra X-ray Spectrum of II Pegasi Chandra X-ray Spectrum of II Pegasi The rate of this energy flow determines the location and size of a crucial stellar region called the convection zone. The zone extends from near the sun's surface inward approximately 125,000 miles. The zone is where the gas undergoes a rolling, convective motion much like the unstable air in a thunderstorm. "This turbulent gas has an extremely important job, because nearly all of the energy emitted at the surface of the sun is transported there by convection," Drake said. The accepted amount of neon in the sun has led to a paradox. The predicted location and size of the solar convection zone disagree with those deduced from solar oscillations. Solar oscillations is a technique astronomers previously relied on to probe the sun's interior. Several scientists have noted the problem could be fixed if the abundance of neon is in fact about three times larger than currently accepted. Attempts to measure the precise amount of neon in the Sun have been frustrated by a quirk of nature; neon atoms in the Sun give off no signatures in visible light. However, in a gas

  16. Massively parallel processor computer

    NASA Technical Reports Server (NTRS)

    Fung, L. W. (Inventor)

    1983-01-01

    An apparatus for processing multidimensional data with strong spatial characteristics, such as raw image data, characterized by a large number of parallel data streams in an ordered array is described. It comprises a large number (e.g., 16,384 in a 128 x 128 array) of parallel processing elements operating simultaneously and independently on single bit slices of a corresponding array of incoming data streams under control of a single set of instructions. Each of the processing elements comprises a bidirectional data bus in communication with a register for storing single bit slices together with a random access memory unit and associated circuitry, including a binary counter/shift register device, for performing logical and arithmetical computations on the bit slices, and an I/O unit for interfacing the bidirectional data bus with the data stream source. The massively parallel processor architecture enables very high speed processing of large amounts of ordered parallel data, including spatial translation by shifting or sliding of bits vertically or horizontally to neighboring processing elements.

  17. Massive soliton stars

    NASA Astrophysics Data System (ADS)

    Chiu, Hong-Yee

    1990-05-01

    The structure of nontopological solutions of Einstein field equations as proposed by Friedberg, Lee, and Pang (1987) is examined. This analysis incorporates finite temperature effects and pair creation. Quarks are assumed to be the only species that exist in interior of soliton stars. The possibility of primordial creation of soliton stars in the incomplete decay of the degenerate vacuum in early universe is explored. Because of dominance of pair creation inside soliton stars, the luminosity of soliton stars is not determined by its radiative transfer characteristics, and the surface temperature of soliton stars can be the same as its interior temperature. It is possible that soliton stars are intense X-ray radiators at large distances. Soliton stars are nearly 100 percent efficient energy converters, converting the rest energy of baryons entering the interior into radiation. It is possible that a sizable number of baryons may also be trapped inside soliton stars during early epochs of the universe. In addition, if soliton stars exist they could assume the role played by massive black holes in galactic centers.

  18. Massive soliton stars

    NASA Technical Reports Server (NTRS)

    Chiu, Hong-Yee

    1990-01-01

    The structure of nontopological solutions of Einstein field equations as proposed by Friedberg, Lee, and Pang (1987) is examined. This analysis incorporates finite temperature effects and pair creation. Quarks are assumed to be the only species that exist in interior of soliton stars. The possibility of primordial creation of soliton stars in the incomplete decay of the degenerate vacuum in early universe is explored. Because of dominance of pair creation inside soliton stars, the luminosity of soliton stars is not determined by its radiative transfer characteristics, and the surface temperature of soliton stars can be the same as its interior temperature. It is possible that soliton stars are intense X-ray radiators at large distances. Soliton stars are nearly 100 percent efficient energy converters, converting the rest energy of baryons entering the interior into radiation. It is possible that a sizable number of baryons may also be trapped inside soliton stars during early epochs of the universe. In addition, if soliton stars exist they could assume the role played by massive black holes in galactic centers.

  19. Massive gauge-flation

    NASA Astrophysics Data System (ADS)

    Nieto, Carlos M.; Rodríguez, Yeinzon

    2016-06-01

    Gauge-flation model at zeroth-order in cosmological perturbation theory offers an interesting scenario for realizing inflation within a particle physics context, allowing us to investigate interesting possible connections between inflation and the subsequent evolution of the Universe. Difficulties, however, arise at the perturbative level, thus motivating a modification of the original model. In order to agree with the latest Planck observations, we modify the model such that the new dynamics can produce a relation between the spectral index ns and the tensor-to-scalar ratio r allowed by the data. By including an identical mass term for each of the fields of the system, we find interesting dynamics leading to slow-roll inflation of the right length. The presence of the mass term has the potential to modify the ns versus r relation so as to agree with the data. As a first step, we study the model at zeroth-order in cosmological perturbation theory, finding the conditions required for slow-roll inflation and the number of e-foldings of inflation. Numerical solutions are used to explore the impact of the mass term. We conclude that the massive version of gauge-flation offers a viable inflationary model.

  20. Volcanogenic Massive Sulfide Deposit Density

    USGS Publications Warehouse

    Mosier, Dan L.; Singer, Donald A.; Berger, Vladimir I.

    2007-01-01

    A mineral-deposit density model for volcanogenic massive sulfide deposits was constructed from 38 well-explored control areas from around the world. Control areas contain at least one exposed volcanogenic massive sulfide deposit. The control areas used in this study contain 150 kuroko, 14 Urals, and 25 Cyprus massive sulfide subtypes of volcanogenic massive sulfide deposits. For each control area, extent of permissive rock, number of exposed volcanogenic massive sulfide deposits, map scale, deposit age, and deposit density were determined. The frequency distribution of deposit densities in these 38 control areas provides probabilistic estimates of the number of deposits for tracts that are permissive for volcanogenic massive sulfide deposits-90 percent of the control areas have densities of 100 or more deposits per 100,000 square kilometers, 50 percent of the control areas have densities of 700 or more deposits per 100,000 square kilometers, and 10 percent of the control areas have densities of 3,700 or more deposits per 100,000 square kilometers. Both map scale and the size of the control area are shown to be predictors of deposit density. Probabilistic estimates of the number of volcanogenic massive sulfide deposits can be made by conditioning the estimates on sizes of permissive area. The model constructed for this study provides a powerful tool for estimating the number of undiscovered volcanogenic massive sulfide deposits when conducting resource assessments. The value of these deposit densities is due to the consistency of these models with the grade and tonnage and the descriptive models. Mineral-deposit density models combined with grade and tonnage models allow reasonable estimates of the number, size, and grades of volcanogenic massive sulfide deposits to be made.

  1. The Destructive Birth of Massive Stars and Massive Star Clusters

    NASA Astrophysics Data System (ADS)

    Rosen, Anna; Krumholz, Mark; McKee, Christopher F.; Klein, Richard I.; Ramirez-Ruiz, Enrico

    2017-01-01

    Massive stars play an essential role in the Universe. They are rare, yet the energy and momentum they inject into the interstellar medium with their intense radiation fields dwarfs the contribution by their vastly more numerous low-mass cousins. Previous theoretical and observational studies have concluded that the feedback associated with massive stars' radiation fields is the dominant mechanism regulating massive star and massive star cluster (MSC) formation. Therefore detailed simulation of the formation of massive stars and MSCs, which host hundreds to thousands of massive stars, requires an accurate treatment of radiation. For this purpose, we have developed a new, highly accurate hybrid radiation algorithm that properly treats the absorption of the direct radiation field from stars and the re-emission and processing by interstellar dust. We use our new tool to perform a suite of three-dimensional radiation-hydrodynamic simulations of the formation of massive stars and MSCs. For individual massive stellar systems, we simulate the collapse of massive pre-stellar cores with laminar and turbulent initial conditions and properly resolve regions where we expect instabilities to grow. We find that mass is channeled to the massive stellar system via gravitational and Rayleigh-Taylor (RT) instabilities. For laminar initial conditions, proper treatment of the direct radiation field produces later onset of RT instability, but does not suppress it entirely provided the edges of the radiation-dominated bubbles are adequately resolved. RT instabilities arise immediately for turbulent pre-stellar cores because the initial turbulence seeds the instabilities. To model MSC formation, we simulate the collapse of a dense, turbulent, magnetized Mcl = 106 M⊙ molecular cloud. We find that the influence of the magnetic pressure and radiative feedback slows down star formation. Furthermore, we find that star formation is suppressed along dense filaments where the magnetic field is

  2. Electromagnetic properties of massive neutrinos

    SciTech Connect

    Dobrynina, A. A. Mikheev, N. V.; Narynskaya, E. N.

    2013-10-15

    The vertex function for a virtual massive neutrino is calculated in the limit of soft real photons. A method based on employing the neutrino self-energy operator in a weak external electromagnetic field in the approximation linear in the field is developed in order to render this calculation of the vertex function convenient. It is shown that the electric charge and the electric dipole moment of the real neutrino are zero; only the magnetic moment is nonzero for massive neutrinos. A fourth-generation heavy neutrino of mass not less than half of the Z-boson mass is considered as a massive neutrino.

  3. Fragmentation in massive star formation.

    PubMed

    Beuther, Henrik; Schilke, Peter

    2004-02-20

    Studies of evolved massive stars indicate that they form in a clustered mode. During the earliest evolutionary stages, these regions are embedded within their natal cores. Here we present high-spatial-resolution interferometric dust continuum observations disentangling the cluster-like structure of a young massive star-forming region. The derived protocluster mass distribution is consistent with the stellar initial mass function. Thus, fragmentation of the initial massive cores may determine the initial mass function and the masses of the final stars. This implies that stars of all masses can form via accretion processes, and coalescence of intermediate-mass protostars appears not to be necessary.

  4. Massive subcutaneous emphysema, pneumomediastinum, and pneumopericardium in children.

    PubMed

    Giuliani, Stefano; Franklin, Ashanti; Pierce, James; Ford, Henri; Grikscheit, Tracy C

    2010-03-01

    Massive subcutaneous emphysema (SE), pneumomediastinum (PM), and pneumopericardium (PP) are rare conditions in the pediatric population. Air leak syndrome is a constellation of disorders that include SE, PM, PP, and pulmonary interstitial emphysema. In children, SE, PM, and PP are associated with obstructive airway disease most often in the case of asthma. Management may be conservative or involve invasive procedures that require surgical intervention. Here, we describe a case of massive SE, PM, and PP in a 10-year-old child after placement of a peripherally inserted central line and review the literature.

  5. Hot Young Solution to Faint Sun Paradox

    NASA Astrophysics Data System (ADS)

    Riofrio, L.

    2006-12-01

    The "Faint Young Sun" has been a paradox of astrophysics. The standard solar model predicts that 4 billion years ago Earth was too cold to support life. Geology and the fossil record contradict this prediction. The paradox and possible solution are a fascinating combination of astrophysics, relativity and the Earth sciences. Models predict that 4 billion years ago the Sun shone with only 70 % of its present luminosity. Since power P is related to temperature T by the Stefan-Boltzmann Law P ∝ T4, Earth temperature would have been only 91 % of its present value. That temperature is approximately 283K, so temperature in the past would have been only 258K. Earth's surface would have frozen solid, making evolution of life very unlikely. Geology shows evidence of extensive sedimentation 4 billion years ago. Other geological markers corroborate the presence of liquid water on Earth during this period. Paleontology dates the earliest organisms at least 3.4 to 4 billion years old. Clearly liquid water and life both existed when the model predicts Earth was frozen solid. This conflict with observations is the Faint Young Sun paradox. Fortunately, Relativity and Space/Time can help save the standard solar model. The Sun converts its fuel to energy according to E=mc2. Unified Space/Time predicts that c is given by: GM=tc3. Where t is age of the Universe, GM combines its mass and gravitational constant. Solving, we have c(t)=(GM)^{1/3} t^{-1/3}. Billions of years ago, solar output and temperature were therefore higher than originally calculated. Earth is estimated to be 4.6 billion years and the Universe 13.7 billion years old, 1.5 times its age at the time of Earth's formation. Energy e=mc2 is adjusted by (1.5)^{2/3} = 1.31 times the initial estimate. Multiplying by that estimate of 70 %, the Sun's actual output was 0.917 of the present value. Temperature was then (0.917)^{1/4} = 98 % of today's value. If we start with an estimate of 76 %, the Sun's true output was exactly

  6. The paradox of evil/homosexuality.

    PubMed

    Woo, Juhyun

    2015-01-01

    In this article, I analyze "personal experience stories around the homosexual" that entered into the parliamentary debates on the Sexual Offences Act in Britain in the 1950s and 1960s and shaped understandings of sexual citizenship in particular ways. Specific attention is paid to the effects of political storytelling involved in the making of British sexual citizens. I explore how the paradoxical figure of the evil homosexual emerges and how politicians, in telling stories of the evil homosexuality, police the border that can effectively separate sexual outsiders from sexual citizens. I conclude with an analysis of these stories, and how their telling is closely linked to the postwar social welfare thinking in Britain.

  7. The paradox of cognitive flexibility in autism.

    PubMed

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

    2009-02-01

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

  8. Simpson's paradox in a synthetic microbial system.

    PubMed

    Chuang, John S; Rivoire, Olivier; Leibler, Stanislas

    2009-01-09

    The maintenance of "public" or "common good" producers is a major question in the evolution of cooperation. Because nonproducers benefit from the shared resource without bearing its cost of production, they may proliferate faster than producers. We established a synthetic microbial system consisting of two Escherichia coli strains of common-good producers and nonproducers. Depending on the population structure, which was varied by forming groups with different initial compositions, an apparently paradoxical situation could be attained in which nonproducers grew faster within each group, yet producers increased overall. We show that a simple way to generate the variance required for this effect is through stochastic fluctuations via population bottlenecks. The synthetic approach described here thus provides a way to study generic mechanisms of natural selection.

  9. Paradoxical Evidence Integration in Rapid Decision Processes

    PubMed Central

    Rüter, Johannes; Marcille, Nicolas; Sprekeler, Henning; Gerstner, Wulfram; Herzog, Michael H.

    2012-01-01

    Decisions about noisy stimuli require evidence integration over time. Traditionally, evidence integration and decision making are described as a one-stage process: a decision is made when evidence for the presence of a stimulus crosses a threshold. Here, we show that one-stage models cannot explain psychophysical experiments on feature fusion, where two visual stimuli are presented in rapid succession. Paradoxically, the second stimulus biases decisions more strongly than the first one, contrary to predictions of one-stage models and intuition. We present a two-stage model where sensory information is integrated and buffered before it is fed into a drift diffusion process. The model is tested in a series of psychophysical experiments and explains both accuracy and reaction time distributions. PMID:22359494

  10. The St. Petersburg paradox: An experimental solution

    NASA Astrophysics Data System (ADS)

    Da Silva, Sergio; Matsushita, Raul

    2016-03-01

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

  11. Aging and communication in the twin paradox

    NASA Astrophysics Data System (ADS)

    de Wolf, David A.

    2016-11-01

    The twin paradox of the special theory of relativity has given rize to a large body of literature discussing its implications. In its standard form, the traveler changes velocity only at the destination of the trip, so that he appears to perceive an improbably instantaneous and non-continuous change in age of the stationary twin. In this work, a smooth velocity/acceleration profile is used that allows the abrupt velocity-change case as a limit. All gravitational effects are ignored in this treatment. Aside from mutual perception of simultaneous clock times in an accelerating frame, constant communication of clock times between the twins by means of (digital) light signals is shown to be possible, in principle if not in practice.

  12. The free quon gas suffers Gibbs' paradox

    SciTech Connect

    Werner, R.F. )

    1993-09-15

    We consider the statistical mechanics of systems of particles satisfying the [ital q]-commutation relations recently proposed by Greenberg and others. We show that although the commutation relations approach Bose (Fermi) relations for [ital q][r arrow]1 ([ital q][r arrow][minus]1), the partition functions of free gases are independent of [ital q] in the range [minus]1[lt][ital q][lt]1. The partition functions exhibit Gibbs' paradox in the same way as a classical gas without a correction factor 1/[ital N] for the statistical weight of the [ital N]-particle phase space; i.e., the statistical mechanics does not describe a material for which entropy, free energy, and particle number are extensive thermodynamical quantities.

  13. Zeno's paradox in decision-making

    PubMed Central

    Yearsley, James M.; Pothos, Emmanuel M.

    2016-01-01

    Classical probability theory has been influential in modelling decision processes, despite empirical findings that have been persistently paradoxical from classical perspectives. For such findings, some researchers have been successfully pursuing decision models based on quantum theory (QT). One unique feature of QT is the collapse postulate, which entails that measurements (or in decision-making, judgements) reset the state to be consistent with the measured outcome. If there is quantum structure in cognition, then there has to be evidence for the collapse postulate. A striking, a priori prediction, is that opinion change will be slowed down (under idealized conditions frozen) by continuous judgements. In physics, this is the quantum Zeno effect. We demonstrate a quantum Zeno effect in decision-making in humans and so provide evidence that advocates the use of quantum principles in decision theory, at least in some cases. PMID:27053743

  14. Zeno's paradox in decision-making.

    PubMed

    Yearsley, James M; Pothos, Emmanuel M

    2016-04-13

    Classical probability theory has been influential in modelling decision processes, despite empirical findings that have been persistently paradoxical from classical perspectives. For such findings, some researchers have been successfully pursuing decision models based on quantum theory (QT). One unique feature of QT is the collapse postulate, which entails that measurements (or in decision-making, judgements) reset the state to be consistent with the measured outcome. If there is quantum structure in cognition, then there has to be evidence for the collapse postulate. A striking, a prioriprediction, is that opinion change will be slowed down (under idealized conditions frozen) by continuous judgements. In physics, this is the quantum Zeno effect. We demonstrate a quantum Zeno effect in decision-making in humans and so provide evidence that advocates the use of quantum principles in decision theory, at least in some cases.

  15. The antioxidant paradox in diabetes mellitus.

    PubMed

    Sheikh-Ali, Mae; Chehade, Joe M; Mooradian, Arshag D

    2011-05-01

    There is ample empiric evidence to indicate that oxidative stress contributes to the pathogenesis of coronary artery disease and has a key role in the onset and progression of diabetes and its complications. Diabetes leads to depletion of the cellular antioxidant defense system and is associated with an increase in the production of free radicals. Oxidative stress can be the result of multiple pathways. Some of these are related to substrate-driven overproduction of mitochondrial reactive oxygen species, advanced glycation end product formation, glucose autoxidation, and depletion of micronutrients and cellular elements with antioxidative properties. There are numerous observational studies in the literature showing a beneficial outcome of the consumption of antioxidant vitamins. However, the interventional trials portray a different picture. The divide between the robust experimental evidence of the pathogenetic role of increased oxidative load in diabetes and the overwhelming failure of antioxidants to show any health benefits in clinical trials may well be characterized as the "antioxidant paradox."

  16. Superlubricity: A Paradox about Confined Fluids Resolved

    NASA Astrophysics Data System (ADS)

    Zhu, Yingxi; Granick, Steve

    2004-08-01

    Using the method of Frantz and Salmeron to cleave mica [

    Tribol. Lett.TRLEFS1023-8883 5, 151 (1998)10.1023/A:1019149910047
    ] we investigate alkane fluids in a surface forces apparatus and confirm several predictions of molecular dynamics (MD) simulation. An oscillatory force-distance profile is observed for the methyl-branched alkane, squalane. Boundary slip is inferred from the frictional sliding of molecularly thin fluids and also from the hydrodynamic flow of thicker films. These findings resolve the paradox that prior experiments disagreed with these aspects of MD predictions, and demonstrate that exceptionally low energy dissipation is possible when fluids move past solid surfaces that are sufficiently smooth.

  17. EPR paradox, quantum nonlocality and physical reality

    NASA Astrophysics Data System (ADS)

    Kupczynski, M.

    2016-03-01

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

  18. Avoiding Braess' Paradox Through Collective Intelligence

    NASA Technical Reports Server (NTRS)

    Wolpert , David H.; Tumer, Kagan

    1999-01-01

    In an Ideal Shortest Path Algorithm (ISPA), at each moment each router in a network sends all of its traffic down the path that will incur the lowest cost to that traffic. In the limit of an infinitesimally small amount of traffic for a particular router, its routing that traffic via an ISPA is optimal, as far as cost incurred by that traffic is concerned. We demonstrate though that in many cases, due to the side-effects of one router's actions on another routers performance, having routers use ISPA's is suboptimal as far as global aggregate cost is concerned, even when only used to route infinitesimally small amounts of traffic. As a particular example of this we present an instance of Braess' paradox for ISPA'S, in which adding new links to a network decreases overall throughput. We also demonstrate that load-balancing, in which the routing decisions are made to optimize the global cost incurred by all traffic currently being routed, is suboptimal as far as global cost averaged across time is concerned. This is also due to "side-effects", in this case of current routing decision on future traffic. The theory of COllective INtelligence (COIN) is concerned precisely with the issue of avoiding such deleterious side-effects. We present key concepts from that theory and use them to derive an idealized algorithm whose performance is better than that of the ISPA, even in the infinitesimal limit. We present experiments verifying this, and also showing that a machine-learning-based version of this COIN algorithm in which costs are only imprecisely estimated (a version potentially applicable in the real world) also outperforms the ISPA, despite having access to less information than does the ISPA. In particular, this COIN algorithm avoids Braess' paradox.

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

    PubMed Central

    Andersen, Cheme; Roust Aaberg, Anne Marie

    2016-01-01

    We describe the care for an elderly woman who was admitted to the intensive care unit (ICU) to receive noninvasive ventilation for acute exacerbation of chronic obstructive pulmonary disease. After administration of the sleeping pill zopiclone, a nonbenzodiazepine receptor agonist (NBRA), the patient became agitated and was confused, a possible paradoxical reaction to benzodiazepines. These symptoms were immediately resolved after treatment with flumazenil, usually used to reverse the adverse effects of benzodiazepines or NBRAs and to reverse paradoxical reactions to benzodiazepines. This case indicates that zopiclone induced behavioral changes resembling a paradoxical reaction to benzodiazepines and these symptoms may be treated with flumazenil. PMID:27672456

  20. A quantum Rosetta Stone for the information paradox

    NASA Astrophysics Data System (ADS)

    Pando Zayas, Leopoldo A.

    2014-11-01

    The black hole information loss paradox epitomizes the contradictions between general relativity and quantum field theory. The AdS/conformal field theory (CFT) correspondence provides an implicit answer for the information loss paradox in black hole physics by equating a gravity theory with an explicitly unitary field theory. Gravitational collapse in asymptotically AdS spacetimes is generically turbulent. Given that the mechanism to read out the information about correlations functions in the field theory side is plagued by deterministic classical chaos, we argue that quantum chaos might provide the true Rosetta Stone for answering the information paradox in the context of the AdS/CFT correspondence.

  1. Linear optics implementation of weak values in Hardy's paradox

    NASA Astrophysics Data System (ADS)

    Ahnert, S. E.; Payne, M. C.

    2004-10-01

    We propose an experimental setup for the implementation of weak measurements in the context of the gedanken experiment known as Hardy’s paradox. As Aharonov et al. [

    Y. Aharonov, A. Botero, S. Popescu, B. Reznik, and J. Tollaksen, Phys. Lett. A301, 130 (2002)
    ] showed, these weak values form a language with which the paradox can be resolved. Our analysis shows that this language is indeed consistent and experimentally testable. It also reveals exactly how a combination of weak values can give rise to an apparently paradoxical result.

  2. Tackling a Hot Paradox: Laminar Soot Processes-2 (LSP-2)

    NASA Technical Reports Server (NTRS)

    Faeth, Gerard M.; Urban, David L.; Over, Ann (Technical Monitor)

    2002-01-01

    The last place you want to be in traffic is behind the bus or truck that is belching large clouds of soot onto your freshly washed car. Besides looking and smelling bad, soot is a health hazard. Particles range from big enough to see to microscopic and can accumulate in the lungs, potentially leading to debilitating or fatal lung diseases. Soot is wasted energy, and therein lies an interesting paradox: Soot forms in a flame's hottest regions where you would expect complete combustion and no waste. Soot enhances the emissions of other pollutants (carbon monoxide and polyaromatic hydrocarbons, etc.) from flames and radiates unwanted heat to combustion chambers (a candle's yellowish glow is soot radiating heat), among other effects. The mechanisms of soot formation are among the most important unresolved problems of combustion science because soot affects contemporary life in so many ways. Although we have used fire for centuries, many fundamental aspects of combustion remain elusive, in part because of limits imposed by the effects of gravity on Earth. Hot or warm air rises quickly and draws in fresh cold air behind it, thus giving flames the classical teardrop shape. Reactions occur in a very small zone, too fast for scientists to observe, in detail, what is happening inside the flame. The Laminar Soot Processes (LSP-2) experiments aboard STS-107 will use the microgravity environment of space to eliminate buoyancy effects and thus slow the reactions inside a flame so they can be more readily studied. 'Laminar' means a simple, smooth fuel jet burning in air, somewhat like a butane lighter. This classical flame approximates combustion in diesel engines, aircraft jet propulsion engines, and furnaces and other devices. LSP-2 will expand on surprising results developed from its first two flights in 1997. The data suggest the existence of a universal relationship, the soot paradigm, that, if proven, will be used to model and control combustion systems on Earth. STS-107

  3. The paradox of enrichment in phytoplankton by induced competitive interactions.

    PubMed

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

    2013-10-03

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

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

    NASA Astrophysics Data System (ADS)

    Vieira, R. S.

    2016-12-01

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

  5. Speech Acts, Communicative Competence and the Paradox of Authority

    ERIC Educational Resources Information Center

    McGuire, R. R.

    1977-01-01

    Attempts to resolve the paradox of authority through an expansion of the theory of speech acts by means of Habermas' theory of communicative competence. Cites the works of Robert Wolff and P.H. Nowell-Smith. (MH)

  6. Paradoxical perception of surfaces in the Shepard tabletop illusion

    PubMed Central

    Tyler, Christopher W

    2011-01-01

    The Shepard tabletop illusion, consisting of different perspective embeddings of two identical parallelograms as tabletops, affords a profound difference in their perceived surface shapes. My analysis reveals three further paradoxical aspects of this illusion, in addition to its susceptibility to the ‘inverse perspective illusion’ of the implied orthographic perspective of the table images. These novel aspects of the illusion are: a paradoxical slant of the tabletops, a paradoxical lack of perceived depth, and a paradoxical distortion of the length of the rear legs. The construction of the illusion resembles scenes found in ancient Chinese scroll paintings, and an analysis of the source of the third effect shows that the interpretation in terms of surfaces can account for the difference in treatment of the filled-in versus open forms in the Chinese painting from more than 1000 years ago. PMID:23145230

  7. Intimate partner violence against women and the Nordic paradox.

    PubMed

    Gracia, Enrique; Merlo, Juan

    2016-05-01

    Nordic countries are the most gender equal countries in the world, but at the same time they have disproportionally high prevalence rates of intimate partner violence (IPV) against women. High prevalence of IPV against women, and high levels of gender equality would appear contradictory, but these apparently opposite statements appear to be true in Nordic countries, producing what could be called the 'Nordic paradox'. Despite this paradox being one of the most puzzling issues in the field, this is a research question rarely asked, and one that remains unanswered. This paper explores a number of theoretical and methodological issues that may help to understand this paradox. Efforts to understand the Nordic paradox may provide an avenue to guide new research on IPV and to respond to this major public health problem in a more effective way.

  8. Contribution of cardiorespiratory fitness to the obesity paradox.

    PubMed

    McAuley, Paul A; Beavers, Kristen M

    2014-01-01

    Until recently, cardiorespiratory fitness (CRF) has been overlooked as a potential modifier of the inverse association between obesity and mortality (the so-called obesity paradox), observed in patients with known or suspected cardiovascular (CV) disease. Evidence from five observational cohort studies of 30,104 patients (87% male) with CV disease indicates that CRF significantly alters the obesity paradox. There is general agreement across studies that the obesity paradox persists among patients with low CRF, regardless of whether adiposity is assessed by body mass index, waist circumference, or percentage body fat. However, among patients with high CRF, risk of all-cause mortality is lowest for the overweight category in some, but not all, studies, suggesting that higher levels of fitness may modify the relationship between body fatness and survival in patients manifesting an obesity paradox. Further study is needed to better characterize the joint contribution of CRF and obesity on mortality in diverse populations.

  9. One-Piece Faraday Generator: A Paradoxical Experiment from 1851

    ERIC Educational Resources Information Center

    Crooks, M. J.; And Others

    1978-01-01

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

  10. Paradox of Migration in Kolkata: A Megacity in GBM Delta

    NASA Astrophysics Data System (ADS)

    Das, S.; Hazra, S.; Ghosh, T.

    2015-12-01

    Contrary to other coastal cities (Mumbai, Chennai, Bhubaneswar etc.) in India, Kolkata, the largest city of India until 1990, has been showing a persistent trend of out-migration over the last decade. The situation is more paradoxical when compared to Dhaka in Bangladesh, the other coastal city in Ganga-Brahmaputra-Meghna (GBM) delta. Exacerbating impacts of Climate Change like accelerated sea level rise, impact of cyclones, rising temperature and high rainfall events and waterlogging, vis-à-vis the density of poor population in slums, Kolkata has been assessed as one of the most vulnerable cities of the world. However, Kolkata has long been a preferred destination for migrants for its port based economy, existence of industrial belt with labour intensive industries. The city and its surrounding districts attracted a massive influx of trans-border migrants when India and Bangladesh gained Independence in 1947 and 1971 respectively. The paper attempts to explore reasons behind the present trend of depopulation in the erstwhile preferred migration destination. This paper distinguishes between 'Kolkata City' (census district) with 4.5 million residents and 'Kolkata Megacity' which encompasses also the peri-urban areas and home to almost 14.1 million people according to Census 2011. Analysing migration as an ongoing research activity under DECCMA project, an overall 'in-migration' pattern can be deciphered in Kolkata 'megacity'. On the contrary, the Kolkata 'city' located right in the heart of the megacity exhibits negative net migration (-5.11%) i.e. high 'out-migration'. Plausible causes can be movement of people from Kolkata 'city' to peri-urban areas and satellite towns (urban to urban migration) probably due to closure of labour intensive industries, comparatively lower land prices, availability of space and accommodation, lower costs of living, development of different modes of commutation and communication. Further growth of population in the Kolkata Megacity

  11. Consumer response: the paradoxes of food and health.

    PubMed

    Biltekoff, Charlotte

    2010-03-01

    The papers in the session "Food Culture and Consumer Response," show how important people's values, beliefs, aspirations and social context are to their dietary health. They also reveal several tensions that shape consumer responses to healthy food. This essay discusses the paradoxical nature of eating habits in general, and describes three paradoxes related specifically to the challenges of providing food for health in the 21st century: pleasure/health, technology/nature, innovation/nostalgia.

  12. Paradoxical Cerebral Fat Embolism in Revision Hip Surgery

    PubMed Central

    Piuzzi, Nicolás S.; Zanotti, Gerardo; Comba, Fernando M.; Buttaro, Martin A.; Piccaluga, Francisco

    2014-01-01

    The incidence of clinical fat embolism syndrome (FES) is low (<1%) whilst fat embolism (FE) of marrow fat appears to occur more often (Mellor and Soni (2001)). Paradoxical brain FE may occur in patients undergoing hip orthopedic surgery who have an undocumented patent foramen ovale (PFO). We report a case of an eighty-year-old male patient, who underwent a scheduled revision hip surgery suffering a paradoxical cerebral FE. PMID:25184065

  13. Holographically viable extensions of topologically massive and minimal massive gravity?

    NASA Astrophysics Data System (ADS)

    Altas, Emel; Tekin, Bayram

    2016-01-01

    Recently [E. Bergshoeff et al., Classical Quantum Gravity 31, 145008 (2014)], an extension of the topologically massive gravity (TMG) in 2 +1 dimensions, dubbed as minimal massive gravity (MMG), which is free of the bulk-boundary unitarity clash that inflicts the former theory and all the other known three-dimensional theories, was found. Field equations of MMG differ from those of TMG at quadratic terms in the curvature that do not come from the variation of an action depending on the metric alone. Here we show that MMG is a unique theory and there does not exist a deformation of TMG or MMG at the cubic and quartic order (and beyond) in the curvature that is consistent at the level of the field equations. The only extension of TMG with the desired bulk and boundary properties having a single massive degree of freedom is MMG.

  14. Is the faint young Sun paradox solved?

    NASA Astrophysics Data System (ADS)

    Wolf, E. T.; Toon, O. B.

    2013-12-01

    How did the early Earth remain warm despite weak solar luminosity? The faint young Sun paradox has stubbornly resisted a self-consistent solution since it was first introduced by Sagan and Mullen [1] over four decades ago. However, recent revisions to expected paleo-ocean temperatures [2, 3] along with new results from three-dimensional climate models [4] may allow this long standing problem to be finally put to rest. Here we use a modified version of the Community Atmosphere Model version 3 from the National Center for Atmospheric Research to study early climate. We find that resolving the faint young Sun paradox becomes less problematic when viewing a full representation of the climate system. For the late Archean climate (80% solar constant), relatively modest amounts of CO2 (≤0.02 bar) and CH4 (0.001 bar) yield surface temperatures equal to the present day with no other alterations to climate. Cooler climates with large ice caps but with temperate tropical regions can be supported with considerably smaller greenhouse gas burdens. The incorporation of systematic climate system elements expected for the Archean such as fewer cloud condensation nuclei (CCN) [5], reduced land albedos [5], and an increased atmospheric inventory of N2 [6], can provide a combined 10 to 20 K of additional surface warming given reasonable assumptions. With the inclusion of 0.001 bar of CH4, 2 PAL of N2, reduced land albedos, and reduced CCN, present day mean surface temperatures can be maintained for the earliest Archean (75% solar constant) with only ~0.01 bar of CO2. However, lower requirements for atmospheric CO2 may imply that photochemical hazes were frequent during the Archean. [1] Sagan, C., & Mullen, G. Science 177, 52 (1972) [2] Hren, M.T., Tice, M.M., & Chamberlin, C.P. Nature 462, 205 (2009) [3] Blake. R.E., Chang, S.J., & Lepland, A. Nature 464, 1029 (2010) [4] Wolf, E.T., & Toon, O.B. Astrobiology 13(7), 1 (2013) [5] Rosing, M.T., Bird, D.K., Sleep, N.H., & Bjerrum, C

  15. Capability and Interface Assessment of Gaming Technologies for Future Multi-Unmanned Air Vehicle Systems

    DTIC Science & Technology

    2011-08-01

    technologies evaluated include Real-Time Strategy (RTS) games , which require the simultaneous control of multiple entities; Massively Multiplayer Online Role...Air Vehicle, Unmanned Air Vehicle Systems, Real-Time Strategy, Massively Multiplayer Online Role Playing Games , Situation Awareness, UAV, UAS, RTS...tested platform for simultaneous control of multiple entities. Similarly, the popularity of Massively Multiplayer Online Role Playing Games (MMORPG

  16. The autophagic paradox in cancer therapy.

    PubMed

    Wu, W K K; Coffelt, S B; Cho, C H; Wang, X J; Lee, C W; Chan, F K L; Yu, J; Sung, J J Y

    2012-02-23

    Autophagy, hallmarked by the formation of double-membrane bound organelles known as autophagosomes, is a lysosome-dependent pathway for protein degradation. The role of autophagy in carcinogenesis is context dependent. As a tumor-suppressing mechanism in early-stage carcinogenesis, autophagy inhibits inflammation and promotes genomic stability. Moreover, disruption of autophagy-related genes accelerates tumorigenesis in animals. However, autophagy may also act as a pro-survival mechanism to protect cancer cells from various forms of cellular stress. In cancer therapy, adaptive autophagy in cancer cells sustains tumor growth and survival in face of the toxicity of cancer therapy. To this end, inhibition of autophagy may sensitize cancer cells to chemotherapeutic agents and ionizing radiation. Nevertheless, in certain circumstances, autophagy mediates the therapeutic effects of some anticancer agents. Data from recent studies are beginning to unveil the apparently paradoxical nature of autophagy as a cell-fate decision machinery. Taken together, modulation of autophagy is a novel approach for enhancing the efficacy of existing cancer therapy, but its Janus-faced nature may complicate the clinical development of autophagy modulators as anticancer therapeutics.

  17. Lagrangian turbulence and the Brownian motion paradox

    NASA Astrophysics Data System (ADS)

    Viecelli, J. A.

    1991-11-01

    The unique properties of three-dimensional hydrodynamic turbulence depend on the nature of the long-range time correlations as well as the spatial correlations. Although Kolmogorov's second similarity hypothesis predicts a power-law spatial scaling exponent for the Eulerian velocity fluctuations in agreement with experiments, it also leads, via the Lagrangian velocity time structure function relationship, to particle dispersion predictions that are inconsistent with enhanced diffusion. Recently, a new computational technique has been developed which can generate random power-law correlated fields in any number of dimensions with unlimited scale range. This new method is used to explore the consequences of a proposed set of assumptions about the nature of the time correlations and their relationship to the spatial correlations. In particular, the Brownian motion paradox is examined and it is shown that it can be resolved if the time domain constraint part of Kolmogorov's second hypothesis is relaxed and replaced with an assumption of space-time isotropy. The proposed modification preserves the observed one-dimensional k-5/3 spatial energy spectrum, allows for enhanced diffusion consistent with Richardson's law, is consistent with Taylor's frozen turbulence assumption under the appropriate conditions, and yields an ω-5/3 frequency spectrum for the velocity fluctuations in a frame at rest with respect to the turbulence.

  18. [Dream in the land of paradoxical sleep].

    PubMed

    Pire, E; Herman, G; Cambron, L; Maquet, P; Poirrier, R

    2008-01-01

    Paradoxical sleep (PS or REM sleep) is traditionally a matter for neurophysiology, a science of the brain. Dream is associated with neuropsychology and sciences of the mind. The relationships between sleep and dream are better understood in the light of new methodologies in both domains, particularly those of basic neurosciences which elucidate the mechanisms underlying SP and functional imaging techniques. Data from these approaches are placed here in the perspective of rather old clinical observations in human cerebral lesions and in the phylogeny of vertebrates, in order to support a theory of dream. Dreams may be seen as a living marker of a cognitivo-emotional process, called here "eidictic process", involving posterior brain and limbic structures, keeping up during wakefulness, but subjected, at that time, to the leading role of a cognitivo-rational process, called here "thought process". The last one is of instrumental origin in human beings. It involves prefrontal cortices (executive tasks) and frontal/parietal cortices (attention) in the brain. Some clinical implications of the theory are illustrated.

  19. The paradoxical zero reflection at zero energy

    NASA Astrophysics Data System (ADS)

    Ahmed, Zafar; Sharma, Vibhu; Sharma, Mayank; Singhal, Ankush; Kaiwart, Rahul; Priyadarshini, Pallavi

    2017-03-01

    Usually, the reflection probability R(E) of a particle of zero energy incident on a potential which converges to zero asymptotically is found to be 1: R(0)=1. But earlier, a paradoxical phenomenon of zero reflection at zero energy (R(0)=0) has been revealed as a threshold anomaly. Extending the concept of half-bound state (HBS) of 3D, here we show that in 1D when a symmetric (asymmetric) attractive potential well possesses a zero-energy HBS, R(0)=0 (R(0)\\ll 1). This can happen only at some critical values q c of an effective parameter q of the potential well in the limit E\\to {0}+. We demonstrate this critical phenomenon in two simple analytically solvable models: square and exponential wells. However, in numerical calculations, even for these two models R(0)=0 is observed only as extrapolation to zero energy from low energies, close to a precise critical value q c. By numerical investigation of a variety of potential wells, we conclude that for a given potential well (symmetric or asymmetric), we can adjust the effective parameter q to have a low reflection at a low energy.

  20. Variational Principles, Occam Razor and Simplicity Paradox

    NASA Astrophysics Data System (ADS)

    Berezin, Alexander A.

    2004-05-01

    Variational minimum principles (VMP) refer to energy (statics, Thomson and Earnshaw theorems in electrostatics), action (Maupertuis, Euler, Lagrange, Hamilton), light (Fermat), quantum paths (Feynman), etc. Historically, VMP appeal to some economy in nature, similarly to Occam Razor Parsimony (ORP) principle. Version of ORP are "best world" (Leibniz), Panglossianism (Voltaire), and "most interesting world" (Dyson). Conceptually, VMP exemplify curious fact that infinite set is often simpler than its subsets (e.g., set of all integers is simpler than set of primes). Algorithmically very simple number 0.1234567... (Champernowne constant) contains Library of Babel of "all books" (Borges) and codes (infinitely many times) everything countably possible. Likewise, full Megaverse (Everett, Deutsch, Guth, Linde) is simpler than our specific ("Big Bang") universe. Dynamically, VMP imply memory effects akin to hysteresis. Similar ideas are "water memory" (Benveniste, Josephson) and isotopic biology (Berezin). Paradoxically, while ORP calls for economy (simplicity), unfolding of ORP in VMP seemingly works in the opposite direction allowing for complexity emergence (e.g., symmetry breaking in Jahn-Teller effect). Metaphysical extrapolation of this complimentarity may lead to "it-from-bit" (Wheeler) reflection of why there is something rather than nothing.

  1. The paradox of enrichment in metaecosystems.

    PubMed

    Gounand, Isabelle; Mouquet, Nicolas; Canard, Elsa; Guichard, Frédéric; Hauzy, Céline; Gravel, Dominique

    2014-12-01

    The paradox of enrichment has been studied almost exclusively within communities or metacommunities, without explicit nutrient dynamics. Yet local recycling of materials from enriched ecosystems may affect the stability of connected ecosystems. Here we study the effect of nutrient, detritus, producer, and consumer spatial flows-combined with changes in regional enrichment-on the stability of a metaecosystem model. We considered both spatially homogeneous and heterogeneous enrichment. We found that nutrient and detritus spatial flows are destabilizing, whereas producer or consumer spatial flows are either neutral or stabilizing. We noticed that detritus spatial flows have only a weak impact on stability. Our study reveals that heterogeneity no longer stabilizes well-connected systems when accounting for explicit representation of nutrient dynamics. We also found that intermediate consumer diffusion could lead to multiple equilibria in strongly enriched metaecosystems. Stability can emerge from a top-down control allowing the storage of materials into inorganic form, a mechanism never documented before. In conclusion, local enrichment can be stabilized if spatial flows are strong enough to efficiently redistribute the local excess of enrichment to unfertile ecosystems. However, high regional enrichment can be dampened only by intermediate consumer diffusion rates.

  2. Mad about Physics: Braintwisters, Paradoxes, and Curiosities

    NASA Astrophysics Data System (ADS)

    Jargodzki, Christopher; Potter, Franklin

    2000-11-01

    Why is there eight times more ice in Antarctica than in the Arctic? Why can you warm your hands by blowing gently, and cool your hands by blowing hard? Why would a pitcher scuff a baseball?Which weighs more-a pound of feathers or a pound of iron? Let science experts Christopher Jargodzki and Franklin Potter guide you through the curiosities of physics and you'll find the answers to these and hundreds of other quirky conundrums. You'll discover why sounds carry well over water (especially in the summer), how a mouse can be levitated in a magnetic field, why backspin is so important when shooting a basketball, and whether women are indeed as strong as men. With nearly 400 questions and answers on everything from race cars to jumping fleas to vanishing elephants, Mad about Physics presents a comprehensive collection of braintwisters and paradoxes that will challenge and entertain even the brainiest of science lovers. Whether you're a physicist by trade or just want to give your brain a power workout, this collection of intriguing and unusual physics challenges will send you on a highly entertaining ride that reveals the relevance of physics in our everyday lives.

  3. Massive ascites of unknown origin

    PubMed Central

    Yuan, Shi-Min

    2014-01-01

    Massive ascites of unknown origin is an uncommon condition, which represent a diagnostic challenge. Patients with delayed diagnosis and treatment may have a poor prognosis. A 22-year-old female was referred to this hospital due to a 4-year progressive abdominal distension with massive ascites of unknown origin. By thorough investigations, she was eventually diagnosed as chronic calcified constrictive pericarditis. She received pericardiectomy and had an uneventful postoperative course. With a few day paracentesis, ascites did not progress any more. She was doing well at 5-month follow-up and has returned to work. Extracardiac manifestations, such as massive ascites and liver cirrhosis, were rare in patients with constrictive pericarditis. Pericardiectomy can be a radical solution for the treatment of chronic constrictive pericarditis. In order to avoid delayed diagnosis and treatment, physicians have to bear in mind this rare manifestation of chronic calcified constrictive pericarditis. PMID:24600502

  4. Positive signs in massive gravity

    SciTech Connect

    Cheung, Clifford; Remmen, Grant N.

    2016-04-01

    Here, we derive new constraints on massive gravity from unitarity and analyticity of scattering amplitudes. Our results apply to a general effective theory defined by Einstein gravity plus the leading soft diffeomorphism-breaking corrections. We calculate scattering amplitudes for all combinations of tensor, vector, and scalar polarizations. Furthermore, the high-energy behavior of these amplitudes prescribes a specific choice of couplings that ameliorates the ultraviolet cutoff, in agreement with existing literature. We then derive consistency conditions from analytic dispersion relations, which dictate positivity of certain combinations of parameters appearing in the forward scattering amplitudes. These constraints exclude all but a small island in the parameter space of ghost-free massive gravity. And while the theory of the "Galileon" scalar mode alone is known to be inconsistent with positivity constraints, this is remedied in the full massive gravity theory.

  5. Positive signs in massive gravity

    DOE PAGES

    Cheung, Clifford; Remmen, Grant N.

    2016-04-01

    Here, we derive new constraints on massive gravity from unitarity and analyticity of scattering amplitudes. Our results apply to a general effective theory defined by Einstein gravity plus the leading soft diffeomorphism-breaking corrections. We calculate scattering amplitudes for all combinations of tensor, vector, and scalar polarizations. Furthermore, the high-energy behavior of these amplitudes prescribes a specific choice of couplings that ameliorates the ultraviolet cutoff, in agreement with existing literature. We then derive consistency conditions from analytic dispersion relations, which dictate positivity of certain combinations of parameters appearing in the forward scattering amplitudes. These constraints exclude all but a small islandmore » in the parameter space of ghost-free massive gravity. And while the theory of the "Galileon" scalar mode alone is known to be inconsistent with positivity constraints, this is remedied in the full massive gravity theory.« less

  6. Positive signs in massive gravity

    NASA Astrophysics Data System (ADS)

    Cheung, Clifford; Remmen, Grant N.

    2016-04-01

    We derive new constraints on massive gravity from unitarity and analyticity of scattering amplitudes. Our results apply to a general effective theory defined by Einstein gravity plus the leading soft diffeomorphism-breaking corrections. We calculate scattering amplitudes for all combinations of tensor, vector, and scalar polarizations. The high-energy behavior of these amplitudes prescribes a specific choice of couplings that ameliorates the ultraviolet cutoff, in agreement with existing literature. We then derive consistency conditions from analytic dispersion relations, which dictate positivity of certain combinations of parameters appearing in the forward scattering amplitudes. These constraints exclude all but a small island in the parameter space of ghost-free massive gravity. While the theory of the "Galileon" scalar mode alone is known to be inconsistent with positivity constraints, this is remedied in the full massive gravity theory.

  7. Processing massive datasets in genomics

    NASA Astrophysics Data System (ADS)

    Artiguenave, F.

    2011-02-01

    Life science researches have been profoundly impacted by technological advances allowing faster and cheaper DNA sequencing. Opening a wide range of applications in medical and biology, the last generation sequencing platforms raised new challenges, in particular in processing, analysing and interpreting massive data. In this talk, the growing role of bioinformatics will be illustrated by providing some figures about genome sequencing and others applications aimed at unravelling biological mechanisms. Methods to gather insights from massive amount of data will be illustrated by the genome annotation process, by which genes are identified in the genome sequence.

  8. Massive photons and Lorentz violation

    NASA Astrophysics Data System (ADS)

    Cambiaso, Mauro; Lehnert, Ralf; Potting, Robertus

    2012-04-01

    All quadratic translation- and gauge-invariant photon operators for Lorentz breakdown are included into the Stueckelberg Lagrangian for massive photons in a generalized Rξ gauge. The corresponding dispersion relation and tree-level propagator are determined exactly, and some leading-order results are derived. The question of how to include such Lorentz-violating effects into a perturbative quantum-field expansion is addressed. Applications of these results within Lorentz-breaking quantum-field theories include the regularization of infrared divergences as well as the free propagation of massive vector bosons.

  9. Genetic Susceptibility and Predictors of Paradoxical Reactions in Buruli Ulcer

    PubMed Central

    Johnson, Roch Christian; Phillips, Richard O.; van der Veer, Eveline; van Diemen, Cleo; van der Werf, Tjip S.; Stienstra, Ymkje

    2016-01-01

    Introduction Buruli ulcer (BU) is the third most frequent mycobacterial disease in immunocompetent persons after tuberculosis and leprosy. During the last decade, eight weeks of antimicrobial treatment has become the standard of care. This treatment may be accompanied by transient clinical deterioration, known as paradoxical reaction. We investigate the incidence and the risks factors associated with paradoxical reaction in BU. Methods The lesion size of participants was assessed by careful palpation and recorded by serial acetate sheet tracings. For every time point, surface area was compared with the previous assessment. All patients received antimicrobial treatment for 8 weeks. Serum concentration of 25-hydroxyvitamin D, the primary indicator of vitamin D status, was determined in duplex for blood samples at baseline by a radioimmunoassay. We genotyped four polymorphisms in the SLC11A1 gene, previously associated with susceptibility to BU. For testing the association of genetic variants with paradoxical responses, we used a binary logistic regression analysis with the occurrence of a paradoxical response as the dependent variable. Results Paradoxical reaction occurred in 22% of the patients; the reaction was significantly associated with trunk localization (p = .039 by Χ2), larger lesions (p = .021 by Χ2) and genetic factors. The polymorphisms 3’UTR TGTG ins/ins (OR 7.19, p < .001) had a higher risk for developing paradoxical reaction compared to ins/del or del/del polymorphisms. Conclusions Paradoxical reactions are common in BU. They are associated with trunk localization, larger lesions and polymorphisms in the SLC11A1 gene. PMID:27097163

  10. Fast, Massively Parallel Data Processors

    NASA Technical Reports Server (NTRS)

    Heaton, Robert A.; Blevins, Donald W.; Davis, ED

    1994-01-01

    Proposed fast, massively parallel data processor contains 8x16 array of processing elements with efficient interconnection scheme and options for flexible local control. Processing elements communicate with each other on "X" interconnection grid with external memory via high-capacity input/output bus. This approach to conditional operation nearly doubles speed of various arithmetic operations.

  11. From Ancient Paradoxes to Modern Orbit Determination

    NASA Astrophysics Data System (ADS)

    Giorgini, Jon D.

    2008-09-01

    In the 5th century BC, Zeno advanced a set of paradoxes to show motion and time are impossible, hence an illusion. The problem of motion has since driven much scientific thought and discovery, extending to Einstein's insights and the quantum revolution. To determine and predict the motion of remote objects within the solar system, a methodology has been refined over centuries. It integrates ideas from astronomy, physics, mathematics, measurement, and probability theory, having motivated most of those developments. Recently generalized and made numerically efficient, statistical orbit determination has made it possible to remotely fly Magellan and other spacecraft through the turbulent atmospheres of Venus and other planets while estimating atmospheric structure and internal mass distributions of the planet. Over limited time-scales, the methodology can predict the position of the Moon within a meter and asteroids within tens of meters -- their velocities at the millimeter per second level -- while characterizing the probable correctness of the prediction. Current software and networks disseminate such ephemeris information in moments; over the last 12 years, 10 million ephemerides have been provided by the Horizons system, at the request of 300000 different users. Applications range from ground and space telescope pointing to correlation with observations recorded on Babylonian cuneiform tablets. Rapid orbit updates are particularly important for planetary radars integrating weak small-body echoes moving quickly through the frequency spectrum due to relative motion. A loop is established in which the predicted delay-Doppler measurement and uncertainties are used to configure the radar. Both predictions are then compared to actual results, the asteroid or comet orbit solution improved, and the radar system optimally adjusted. Still, after 2500 years and tremendous descriptive success, there remain substantial problems understanding and predicting motion.

  12. Paradoxical monocular stereopsis and perspective vergence

    NASA Technical Reports Server (NTRS)

    Enright, J. T.

    1989-01-01

    The question of how to most effectively convey depth in a picture is a multifaceted problem, both because of potential limitations of the chosen medium (stereopsis, image motion), and because effectiveness can be defined in various ways. Practical applications usually focus on information transfer, i.e., effective techniques for evoking recognition of implied depth relationships, but this issue depends on subjective judgements which are difficult to scale when stimuli are above threshold. Two new approaches to this question are proposed here which are based on alternative criteria for effectiveness. Paradoxical monocular stereopsis is a remarkably compelling impression of depth which is evoked during one-eyed viewing of only certain illustrations; it can be unequivocally recognized because the feeling of depth collapses when one shifts to binocular viewing. An exploration of the stimulus properties which are effective for this phenomenon may contribute useful answers for the more general perceptual problem. Positive vergence is an eye-movement response associated with changes of fixation point within a picture which implies depth; it also arises only during monocular viewing. The response is directionally appropriate (i.e., apparently nearer objects evoke convergence, and vice versa), but the magnitude of the response can be altered consistently by making relatively minor changes in the illustration. The cross-subject agreement in changes of response magnitude would permit systematic exploration to determine which stimulus configurations are most effective in evoking perspective vergence, with quantitative answers based upon this involuntary reflex. It may well be that most effective pictures in this context will embody features which would increase effectiveness of pictures in a more general sense.

  13. Molecular pathological epidemiology gives clues to paradoxical findings.

    PubMed

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

    2015-10-01

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

  14. Where Was Everybody? Olaf Stapledon and the Fermi Paradox

    NASA Astrophysics Data System (ADS)

    Baxter, S.

    In 1948 Olaf Stapledon gave an address to the BIS in which he summarised his vision of mankind's cosmic future: `One can imagine some sort of cosmical community of worlds ...' One might ask, however, since the universe is vastly older than mankind, why races on other worlds have not already built such a community. This is a `Fermi Paradox' question. The Paradox is based on the observation that there has been time for extraterrestrial intelligence to arise and colonise the Galaxy many times over, yet we see no sign of such endeavours. In this paper Stapledon's novels are retrospectively analysed from the point of view of the Fermi Paradox. In Last and First Men (1930) humanity is forever isolated because life and mind are rare in the Galaxy, and interstellar distances are too large ever to be traversed. These are classic candidate Fermi `solutions'. The `solution' implicit in Star Maker (1937) might be criticised in that it posits that humanity lives at a special epoch, with the cosmically transforming development of interstellar travel occurring a `mere' ten billion years after mankind, in a universe supposedly ~200bn years old. Stapledon died in 1950, the year the Paradox was formulated, and was probably unaware of the Paradox. However to apply retrospectively Fermi thinking to Stapledon's cosmologies is to gain a new insight into the author's philosophy.

  15. Fermi's Paradox Is a Daunting Problem, Under Whatever Label

    NASA Astrophysics Data System (ADS)

    Čirković, Milan M.

    2016-10-01

    Gray (2015) argued that the Fermi paradox (FP) is a misnomer, and it is not a valid paradox. Gray also speculated that the argument was misattributed to Fermi, whose lunchtime remarks did not pertain to the existence of extraterrestrial intelligence, but to the feasibility of interstellar travel. Instead, the paradox is ascribed to Hart and Tipler, and it is further suggested that the paradox is not a real problem or research subject and should not be used in debates about SETI projects. The arguments given are unpersuasive, ahistorical, and, in at least one instance, clearly hinge on literalistic and uncharitable reading of evidence. Instead, I argue the following three points: (i) Contrary to Gray's assertion, the historical issue of naming of ideas or concepts is completely divorced from their epistemic status. (ii) FP is easily and smoothly generalized into the Great Silence paradox, so it makes no sense either theoretically or empirically to separate the two. (iii) In sharp contrast to the main implication of Gray's paper, FP has become more aggravated lately due to advances in astrobiology.

  16. Is "healthy dying" a paradox? revisiting an early Kastenbaum challenge.

    PubMed

    Kellehear, Allan

    This article is a review of Robert Kastenbaum's 1979 essay entitled "Healthy dying: A paradoxical quest continues." It begins with a summary of the arguments and challenges in the original essay. This is followed by an evaluation of his original claims in the light of contemporary insights in modern public health history and empirical studies of near-death experiences and death bed visions. The recent development of health promotion in palliative care is described in relation to these developments and Kastenbaum's early question about the paradoxical quest for health while dying is again posed against this background. Given our modern understanding of "health" in current global health policy and debates, it is argued that "healthy dying" is no paradox. Instead, the pursuit of health at the end of life represents a realistic modern desire to compress morbidity, minimize unnecessary suffering, and enhance quality of life at this time.

  17. Seismic Exploration for Pennsylvanian Algal Mounds, Paradox Basin

    SciTech Connect

    Moriarty, B.; Grundy, R.

    1985-05-01

    During the past 2 years, several new field discoveries were drilled in Pennsylvanian algal mounds of the Paradox basin. Most of these discoveries were based, at least partially, on state-of-the-art seismic data. New field production comes from either the Ismay or Desert Creek zones the Paradox Formation. The algal correlate laterally with either marine shelf or penesaline facies. Detection of the Ismay and Desert Creek buildups is difficult because of their limited thickness. Therefore, the acquisition of good signal-to-noise high-frequency data and stratigraphic processing for frequency enhancement are both critical for successful seismic exploration in the Paradox basin. Bug, Patterson, Ismay, Cache, and Rockwell Springs fields are characteristic of Desert Creek and Ismay stratigraphic trapping.

  18. The ethical use of paradoxical interventions in psychotherapy.

    PubMed Central

    Foreman, D M

    1990-01-01

    The purpose of this paper is to establish ethical guidelines for the use of paradoxical interventions in psychotherapy. These are defined as interventions which are counterintuitive, coercive, and which require non-observance by the client. Arguments are developed to show that such interventions are associated with a psychology that understands individuals solely in terms of their relationship: a 'strong interactionist' position. Ethical principles consistent with such a position are considered, and from these it is derived that: paradox is an ethical technique with resistive patients; it requires consent; its content should be consistent with general ethical principles, especially those of beneficence and non-maleficence; non-paradoxical techniques should be preferred when possible; and it should not be used as an assessment procedure. It is concluded that research is needed to explore the effect of such ethical guidelines of effectiveness, though preliminary impressions are encouraging. PMID:2287016

  19. Traversing boundaries: thrombus in transit with paradoxical embolism

    PubMed Central

    Miriyala, Varun; Faraj, Kirmanj; Nagra, Bipinpreet

    2016-01-01

    A 72-year-old male is diagnosed with paradoxical embolus after he presented with concurrent deep vein thrombosis, stroke, and multiple arterial emboli in the presence of a patent foramen ovale (PFO). Paradoxical embolus requires the passage of a thrombus from the venous into the arterial circulation through a right-to-left shunt leading to systemic embolism. But, despite the high incidence of PFO (27.3% across all age groups by autopsy), paradoxical embolism (PDE) is uncommon, representing <2% of all arterial emboli. We present a case report where a thrombus has been directly observed passing through the PFO during an echocardiogram study; thus, clearly delineating the true cause of multiple thromboemboli and stoke in our patient. Subsequent Transesophageal Echocardiography (TEE) also interestingly showed the thrombus in transit in the aorta and pulmonary artery. PMID:27609716

  20. Caloric stimulation with near infrared radiation does not induce paradoxical nystagmus.

    PubMed

    Walther, L E; Asenov, D R; Di Martino, E

    2011-04-01

    Near infrared radiation can be used for warm stimulation in caloric irrigation of the equilibrium organ. Aim of this study was to determine whether near infrared radiation offers effective stimulation of the vestibular organ, whether it is well tolerated by the patients and especially whether it is a viable alternative to warm air stimulation in patients with defects of the tympanic membrane and radical mastoid cavities. Patients with perforations of the tympanic membrane (n = 15) and with radical mastoid cavities (n = 13) were tested both with near infrared radiation and warm dry air. A caloric-induced nystagmus could be seen equally effectively and rapidly in all patients. Contrary to stimulation with warm dry air, no paradoxical nystagmus was observed following caloric irrigation with a warm stimulus (near infrared radiation). Results of a questionnaire showed excellent patient acceptance of near infrared stimulation with no arousal effects or unpleasant feeling. In conclusion, near infrared radiation proved to be an alternative method of caloric irrigation to warm dry air in patients with tympanic membrane defects and radical mastoid cavities. Near infrared radiation is pleasant, quick, contact free, sterile and quiet. With this method an effective caloric warm stimulus is available. If near infrared radiation is used for caloric stimulus no evaporative heat loss occurs.

  1. The calcium paradox in isolated frog heart: Ringer revisited.

    PubMed

    Ruigrok, T J; Slade, A M; Poole-Wilson, P A

    1983-12-01

    Restoration of a normal calcium concentration in the perfusate of isolated hearts after a short period of calcium-free perfusion may result in irreversible cell damage (calcium paradox). We have compared the calcium paradox in rat and frog hearts. Perfusion with zero calcium for 8 min at 37 degrees C predisposed the rat heart to the paradox. After the reintroduction of calcium to the perfusate resting tension rose, developed tension did not recover, ultrastructural changes occurred and enzyme loss was substantial. In the frog heart a calcium paradox did not occur after 8 min of calcium-free perfusion at 23 degrees C. Removal of both potassium and calcium caused a rise in resting tension on reintroduction of control solution, but the rise was only transient and absent if potassium was present during the perfusion with zero calcium. At 37 degrees C no complete calcium paradox occurred after 8 min calcium-free perfusion. Only a small rise in resting tension was apparent, and developed tension partially recovered. A calcium paradox could only be induced in the frog heart after calcium-free perfusion at 37 degrees C for 30 min. Ultrastructural changes were apparent and resting tension rose but even under these conditions the recovery of developed tension was not abolished. Release of creatine kinase was 161 +/- 55 IU/g dry tissue during the 15 min after reintroduction of calcium (n = 5). Calcium-free perfusion for 8 min resulted in a smaller release of creatine kinase over 15 min (39 +/- 11 IU/g dry tissue. n = 5).(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Massive binary stars as a probe of massive star formation

    NASA Astrophysics Data System (ADS)

    Kiminki, Daniel C.

    2010-10-01

    Massive stars are among the largest and most influential objects we know of on a sub-galactic scale. Binary systems, composed of at least one of these stars, may be responsible for several types of phenomena, including type Ib/c supernovae, short and long gamma ray bursts, high-velocity runaway O and B-type stars, and the density of the parent star clusters. Our understanding of these stars has met with limited success, especially in the area of their formation. Current formation theories rely on the accumulated statistics of massive binary systems that are limited because of their sample size or the inhomogeneous environments from which the statistics are collected. The purpose of this work is to provide a higher-level analysis of close massive binary characteristics using the radial velocity information of 113 massive stars (B3 and earlier) and binary orbital properties for the 19 known close massive binaries in the Cygnus OB2 Association. This work provides an analysis using the largest amount of massive star and binary information ever compiled for an O-star rich cluster like Cygnus OB2, and compliments other O-star binary studies such as NGC 6231, NGC 2244, and NGC 6611. I first report the discovery of 73 new O or B-type stars and 13 new massive binaries by this survey. This work involved the use of 75 successful nights of spectroscopic observation at the Wyoming Infrared Observatory in addition to observations obtained using the Hydra multi-object spectrograph at WIYN, the HIRES echelle spectrograph at KECK, and the Hamilton spectrograph at LICK. I use these data to estimate the spectrophotometric distance to the cluster and to measure the mean systemic velocity and the one-sided velocity dispersion of the cluster. Finally, I compare these data to a series of Monte Carlo models, the results of which indicate that the binary fraction of the cluster is 57 +/- 5% and that the indices for the power law distributions, describing the log of the periods, mass

  3. The calcium paradox - what should we have to fear?

    PubMed

    Oliveira, Marcos Aurélio Barboza de; Brandi, Antônio Carlos; Dos Santos, Carlos Alberto; Botelho, Paulo Henrique Husseni; Cortez, José Luís Lasso; Goissis, Gilberto; Braile, Domingo Marcolino

    2014-01-01

    The calcium paradox was first mentioned in 1966 by Zimmerman et al. Thereafter gained great interest from the scientific community due to the fact of the absence of calcium ions in heart muscle cells produce damage similar to ischemia-reperfusion. Although not all known mechanisms involved in cellular injury in the calcium paradox intercellular connection maintained only by nexus seems to have a key role in cellular fragmentation. The addition of small concentrations of calcium, calcium channel blockers, and hyponatraemia hypothermia are important to prevent any cellular damage during reperfusion solutions with physiological concentration of calcium.

  4. The calcium paradox - What should we have to fear?

    PubMed Central

    de Oliveira, Marcos Aurélio Barboza; Brandi, Antônio Carlos; dos Santos, Carlos Alberto; Botelho, Paulo Henrique Husseni; Cortez, José Luís Lasso; Goissis, Gilberto; Braile, Domingo Marcolino

    2014-01-01

    The calcium paradox was first mentioned in 1966 by Zimmerman et al. Thereafter gained great interest from the scientific community due to the fact of the absence of calcium ions in heart muscle cells produce damage similar to ischemia-reperfusion. Although not all known mechanisms involved in cellular injury in the calcium paradox intercellular connection maintained only by nexus seems to have a key role in cellular fragmentation. The addition of small concentrations of calcium, calcium channel blockers, and hyponatraemia hypothermia are important to prevent any cellular damage during reperfusion solutions with physiological concentration of calcium. PMID:25140476

  5. New branches of massive gravity

    NASA Astrophysics Data System (ADS)

    Comelli, D.; Crisostomi, M.; Koyama, K.; Pilo, L.; Tasinato, G.

    2015-06-01

    The basic building block for Lorentz-invariant and ghost-free massive gravity is the square root of the combination g-1η , where g-1 is the inverse of the physical metric and η is a reference metric. Since the square root of a matrix is not uniquely defined, it is possible to have physically inequivalent potentials corresponding to different branches. We show that around the Minkowski background, the only perturbatively well-defined branch is the potential proposed by de Rham, Gabadadze and Tolley. On the other hand, if Lorentz symmetry is broken spontaneously, other potentials exist with a standard perturbative expansion. We show this explicitly building new Lorentz-invariant, ghost-free massive gravity potentials for theories that in the background preserve rotational invariance but break Lorentz boosts.

  6. Black holes in massive gravity

    NASA Astrophysics Data System (ADS)

    Babichev, Eugeny; Brito, Richard

    2015-08-01

    We review the black hole (BH) solutions of the ghost-free massive gravity theory and its bimetric extension, and outline the main results on the stability of these solutions against small perturbations. Massive (bi)-gravity accommodates exact BH solutions, analogous to those of general relativity (GR). In addition to these solutions, hairy BHs—solutions with no correspondent in GR—have been found numerically, whose existence is a natural consequence of the absence of Birkhoff’s theorem in these theories. The existence of extra propagating degrees of freedom, makes the stability properties of these BHs richer and more complex than those of GR. In particular, the bi-Schwarzschild BH exhibits an unstable spherically symmetric mode, while the bi-Kerr geometry is also generically unstable, both against the spherical mode and against superradiant instabilities. If astrophysical BHs are described by these solutions, the superradiant instability of the Kerr solution imposes stringent bounds on the graviton mass.

  7. Topologically massive higher spin gravity

    NASA Astrophysics Data System (ADS)

    Bagchi, Arjun; Lal, Shailesh; Saha, Arunabha; Sahoo, Bindusar

    2011-10-01

    We look at the generalisation of topologically massive gravity (TMG) to higher spins, specifically spin-3. We find a special "chiral" point for the spin-three, analogous to the spin-two example, which actually coincides with the usual spin-two chiral point. But in contrast to usual TMG, there is the presence of a non-trivial trace and its logarithmic partner at the chiral point. The trace modes carry energy opposite in sign to the traceless modes. The logarithmic partner of the traceless mode carries negative energy indicating an instability at the chiral point. We make several comments on the asymptotic symmetry and its possible deformations at this chiral point and speculate on the higher spin generalisation of LCFT2 dual to the spin-3 massive gravity at the chiral point.

  8. Spin-3 topologically massive gravity

    NASA Astrophysics Data System (ADS)

    Chen, Bin; Long, Jiang; Wu, Jun-bao

    2011-11-01

    In this Letter, we study the spin-3 topologically massive gravity (TMG), paying special attention to its properties at the chiral point. We propose an action describing the higher spin fields coupled to TMG. We discuss the traceless spin-3 fluctuations around the AdS3 vacuum and find that there is an extra local massive mode, besides the left-moving and right-moving boundary massless modes. At the chiral point, such extra mode becomes massless and degenerates with the left-moving mode. We show that at the chiral point the only degrees of freedom in the theory are the boundary right-moving graviton and spin-3 field. We conjecture that spin-3 chiral gravity with generalized Brown-Henneaux boundary condition is holographically dual to 2D chiral CFT with classical W3 algebra and central charge cR = 3 l / G.

  9. Formation of Massive Stars: Theoretical Considerations

    NASA Technical Reports Server (NTRS)

    Yorke, Harold W.

    2008-01-01

    This slide presentation reviews theoretical considerations of the formation of massive stars. It addresses the questions that assuming a gravitationally unstable massive clump, how does enough material become concentrated into a sufficiently small volume within a sufficiently short time? and how does the forming massive star influence its immediate surroundings to limit its mass?

  10. Theoretical Considerations of Massive Star Formation

    NASA Technical Reports Server (NTRS)

    Yorke, Harold W.

    2006-01-01

    This viewgraph presentation reviews the formation of massive stars. The formation of massive stars is different in many ways from the formation of other stars. The presentation shows the math, and the mechanisms that must be possible for a massive star to form.

  11. Massive star clusters in galaxies.

    PubMed

    Harris, William E

    2010-02-28

    The ensemble of all star clusters in a galaxy constitutes its star cluster system. In this review, the focus of the discussion is on the ability of star clusters, particularly the systems of old massive globular clusters (GCs), to mark the early evolutionary history of galaxies. I review current themes and key findings in GC research, and highlight some of the outstanding questions that are emerging from recent work.

  12. Voids in massive neutrino cosmologies

    SciTech Connect

    Massara, Elena; Villaescusa-Navarro, Francisco; Viel, Matteo; Sutter, P.M. E-mail: villaescusa@oats.inaf.it E-mail: sutter@oats.inaf.it

    2015-11-01

    Cosmic voids are a promising environment to characterize neutrino-induced effects on the large-scale distribution of matter in the universe. We perform a comprehensive numerical study of the statistical properties of voids, identified both in the matter and galaxy distributions, in massive and massless neutrino cosmologies. The matter density field is obtained by running several independent N-body simulations with cold dark matter and neutrino particles, while the galaxy catalogs are modeled by populating the dark matter halos in simulations via a halo occupation distribution (HOD) model to reproduce the clustering properties observed by the Sloan Digital Sky Survey (SDSS) II Data Release 7. We focus on the impact of massive neutrinos on the following void statistical properties: number density, ellipticities, two-point statistics, density and velocity profiles. Considering the matter density field, we find that voids in massive neutrino cosmologies are less evolved than those in the corresponding massless neutrinos case: there is a larger number of small voids and a smaller number of large ones, their profiles are less evacuated, and they present a lower wall at the edge. Moreover, the degeneracy between σ{sub 8} and Ω{sub ν} is broken when looking at void properties. In terms of the galaxy density field, we find that differences among cosmologies are difficult to detect because of the small number of galaxy voids in the simulations. Differences are instead present when looking at the matter density and velocity profiles around these voids.

  13. Extinction in young massive clusters

    NASA Astrophysics Data System (ADS)

    De Marchi, Guido; Panagia, Nino

    2016-01-01

    Up to ages of ~100 Myr, massive clusters are still swamped in large amounts of gas and dust, causing considerable and uneven levels of extinction. At the same time, large grains (ices?) produced by type II supernovae profoundly alter the interstellar medium (ISM), thus resulting in extinction properties very different from those of the diffuse ISM. To obtain physically meaningful parameters of stars (luminosities, effective temperatures, masses, ages, etc.) we must understand and measure the local extinction law. We have developed a powerful method to unambiguously determine the extinction law everywhere across a cluster field, using multi-band photometry of red giant stars belonging to the red clump (RC) and are applying it to young massive clusters in the Local Group. In the Large Magellanic Cloud, with about 20 RC stars per arcmin2, for each field we can easily derive an accurate extinction curve over the entire wavelength range of the photometry. As an example, we present the extinction law of the Tarantula nebula (30 Dor) based on thousands of stars observed as part of the Hubble Tarantula Treasury Project. We discuss how the incautious adoption of the Milky Way extinction law in the analysis of massive star forming regions may lead to serious underestimates of the fluxes and of the star formation rates by factors of 2 or more.

  14. Creative Paradoxical Thinking and Its Implications for Teaching and Learning Motor Skills

    ERIC Educational Resources Information Center

    Chen, David

    2011-01-01

    A paradox is a statement or situation that involves two or more contradictory, mutually exclusive elements that operate at the same time. This article examines a number of findings in motor-learning and motor-control research and categorizes them into six paradoxes. Based on those research findings, the concept of creative paradoxical thinking is…

  15. Characterization of the calcium paradox in the isolated perfused frog heart: enzymatic, ionic, contractile and electrophysiological studies.

    PubMed

    Touraki, M; Beis, I

    1990-01-01

    The effect of perfusion temperature and duration of calcium deprivation on the occurrence of the calcium paradox was studied in the isolated frog heart. Loss of electrical and mechanical activity, ion fluxes, creatine kinase and protein release were used to define cell damage. Perfusion was performed at 22, 27, 32, and 37 degrees C, and calcium deprivation lasted 10, 20, 30, or 40 min. At 22 degrees C and 27 degrees C even a prolonged calcium-free perfusion failed to induce a calcium paradox. After 30 min of calcium-free perfusion at 37 degrees C ventricular activity ceased and a major contraction occurred followed by an increase in resting tension. During the 15-min re-perfusion period the release of creatine kinase was 158.24 +/- 2.49 IU.g dry wt-1, and the total amount of protein lost was 70.37 +/- 0.73 mg.g dry wt-1, while lower perfusion temperatures resulted in a decreased loss of protein and creatine kinase. Ion fluxes in the perfusion effluent indicate that during re-perfusion a massive calcium influx accompanied by a potassium and a magnesium efflux, and an apparent sodium efflux, occur at a perfusion temperature of 37 degrees C after 30 min of calcium deprivation. The results suggest that the basic principles and damaging effects of calcium overloading are common to both mammalian and frog hearts.

  16. Massive Stars in Interactive Binaries

    NASA Astrophysics Data System (ADS)

    St.-Louis, Nicole; Moffat, Anthony F. J.

    Massive stars start their lives above a mass of ~8 time solar, finally exploding after a few million years as core-collapse or pair-production supernovae. Above ~15 solar masses, they also spend most of their lives driving especially strong, hot winds due to their extreme luminosities. All of these aspects dominate the ecology of the Universe, from element enrichment to stirring up and ionizing the interstellar medium. But when they occur in close pairs or groups separated by less than a parsec, the interaction of massive stars can lead to various exotic phenomena which would not be seen if there were no binaries. These depend on the actual separation, and going from wie to close including colliding winds (with non-thermal radio emission and Wolf-Rayet dust spirals), cluster dynamics, X-ray binaries, Roche-lobe overflow (with inverse mass-ratios and rapid spin up), collisions, merging, rejuventation and massive blue stragglers, black-hole formation, runaways and gamma-ray bursts. Also, one wonders whether the fact that a massive star is in a binary affects its parameters compared to its isolated equivalent. These proceedings deal with all of these phenomena, plus binary statistics and determination of general physical properties of massive stars, that would not be possible with their single cousins. The 77 articles published in these proceedings, all based on oral talks, vary from broad revies to the lates developments in the field. About a third of the time was spent in open discussion of all participants, both for ~5 minutes after each talk and 8 half-hour long general dialogues, all audio-recorded, transcribed and only moderately edited to yield a real flavour of the meeting. The candid information in these discussions is sometimes more revealing than the article(s) that preceded them and also provide entertaining reading. The book is suitable for researchers and graduate students interested in stellar astrophysics and in various physical processes involved when

  17. The hierarchical model of stem cell genesis explains the man mouse paradox, Peto's paradox, the red cell paradox and Wright's enigma.

    PubMed

    Morris, James A

    2014-12-01

    The central dogma of carcinogenesis is that deleterious mutations accumulate in regularly cycling stem cells and eventually one of the cells will acquire a specific set of mutations which leads to uncontrolled cell proliferation. Each mutation is rare and the specific set is extremely rare so that even though there are millions of stem cells in a small area of mucosa the specific set of mutations to initiate the process of malignancy will only arise in one stem cell at most; hence neoplasia is clonal. But this model predicts that men, who are 1000 times larger than mice and live 30 times as long, should have a vastly increased risk of cancer compared with mice, but they don't (man-mouse paradox). The model also predicts that the prevalence of cancer in men should rise as power function of age and mutagen dose, the former is correct but not the latter (Peto's paradox). Furthermore there are more mitotic divisions in red cell precursors than in all other stem cells combined and yet erythroleukaemia is rare (red cell paradox). The central dogma is also challenged by Wright's enigma; the observation that some gastro-intestinal neoplasms are polyclonal in origin. The problem with the central dogma is the concept of a regularly cycling stem cell. In fact it is possible to produce all the cells that arise in a human lifetime with fewer than 60 rounds of DNA replication separating the zygote from mature differentiated cells in extreme old age. This hierarchical model of stem cell genesis leads to a very low prevalence of cancer, unless the orderly progression of the hierarchy is disturbed by inflammation, ulceration or trauma. This model explains the paradoxes and Wright's enigma. It is suggested that the number of cell divisions that separate the zygote from stem cells is a key variable in carcinogenesis.

  18. Paradox in Paradise: The Black Image in Revolutionary America.

    ERIC Educational Resources Information Center

    Collier, Eugenia

    1991-01-01

    Examines the literature and explores the portrayal of African Americansin creative writings of revolutionary America. The literature of the period reveals the paradox of African-American life in America, where prosperity for some was based on exploitation of others. Works of Benjamin Banneker, Thomas Jefferson, and Phyllis Wheatley are cited. (SLD)

  19. The Power of Paradox in Learning to Teach

    ERIC Educational Resources Information Center

    Noordhoff, Karen

    2012-01-01

    This chapter makes the case for engaging teacher candidates with matters of personal identity and integrity, using explorations of the paradox of self and role, in teacher education programs dominated by a focus on professional knowledge and skills, based on the analysis of interviews with novice teachers. The author argues that both teacher…

  20. A Powerful Theory and a Paradox: Ecological Psychologists after Barker

    ERIC Educational Resources Information Center

    Scott, M. M.

    2005-01-01

    Roger Barker, influenced by Lewin, developed a powerful theory in psychology, behavior setting theory. Paradoxically, this theory is still not widely known or understood in mainstream American psychology. Oral histories of the core group who worked with Barker were collected and examined to determine influences on them and subsequent directions in…

  1. The Punitive Paradox: Desert and the Compulsion to Punish.

    ERIC Educational Resources Information Center

    Clear, Todd R.

    1996-01-01

    Explores the concept of a "just deserts" justice paradox in which carrying out a deserved penalty breaches the values that undergird the theory of just deserts. Examines whether it might ever be proper, from a desert perspective, to choose not to impose a deserved punishment. (KW)

  2. Paradox of Our Times: Hunger in a Strong Economy.

    ERIC Educational Resources Information Center

    Venner, Sandra H.; Sullivan, Ashley F.; Seavey, Dorie

    America today is haunted by the paradox of hunger and food insecurity amidst unprecedented prosperity. Despite a record economic expansion, millions of American households struggle to find sufficient resources to feed family members. Focusing on families with children, this report presents current evidence on hunger and food insecurity, identifies…

  3. The Paradox of Reducing Class Size and Improving Learning Outcomes

    ERIC Educational Resources Information Center

    Hattie, John

    2005-01-01

    This paper addresses four questions: What are the effects of reducing class size? How important are these effects? How can we explain these effects? and How can we improve the outcomes when class sizes are reduced? A major aim is to provide directions for resolving the paradox as to "Why reducing class size has not led to major improvements in…

  4. A Paradoxical Academic Identity: Fate, Utopia and Critical Hope

    ERIC Educational Resources Information Center

    Sutton, Paul

    2015-01-01

    Using a dialectical mode of exposition, I offer a reflexive sociological theorisation of the paradox that characterises my academic identity: a fatalistic disenchantment concerning the colonisation of Higher Education (HE) by neoliberalism co-exists with a utopianism concerning HE's emancipatory possibilities. I begin with a discussion of Weber's…

  5. THE PARADOX OF THE PLANKTON: COMMUNITY STRUCTURE PROMOTES BLOOMS

    EPA Science Inventory

    ABSTRACT: The 'paradox of the plankton' refers to commensalism as well as symbiosis, predation, and impacts of non equilibrium conditions between two planktonic

    competitors. In regards to commensalism, phytoplankton can release organic carbon that enhances growth of its ba...

  6. Confucius Institutes and China's Soft Power: Practices and Paradoxes

    ERIC Educational Resources Information Center

    Lo, Joe Tin-yau; Pan, Suyan

    2016-01-01

    Since China's implementation of the Confucius Institute (CI) project in 2004, most academic works have been written on its objectives, nature, features, development, problems and challenges, especially in terms of soft power projection. Though some of them could unravel the tensions and paradoxes in the CI project, there is a paucity of in-depth…

  7. The Use of Paradoxes as an Instructional Strategy.

    ERIC Educational Resources Information Center

    Rastovac, John J.; Slavsky, David B.

    1986-01-01

    Describes a study in which paradoxes about seasons, hemispheres, and altitude were used to teach concepts in climatology. The misconceptions commonly held about the earth-sun distance relationship were used as an instructional strategy with an experimental group, which outgained the control group on an achievement test. (TW)

  8. Some Paradoxical Results for the Quadratically Weighted Kappa

    ERIC Educational Resources Information Center

    Warrens, Matthijs J.

    2012-01-01

    The quadratically weighted kappa is the most commonly used weighted kappa statistic for summarizing interrater agreement on an ordinal scale. The paper presents several properties of the quadratically weighted kappa that are paradoxical. For agreement tables with an odd number of categories "n" it is shown that if one of the raters uses the same…

  9. The Paradox of Professional Community: Tales from Two High Schools.

    ERIC Educational Resources Information Center

    Scribner, Jay Paredes; Hager, Douglas R.; Warne, Tara R

    2002-01-01

    Case study of two urban high schools explores how, paradoxically, professional autonomy and attention to individual needs are necessary and salient conditions of strong professional communities. Focuses on the important role that principals play in balancing individual and organizational needs and fostering professional community. Reinterprets…

  10. Scrounging by foragers can resolve the paradox of enrichment

    PubMed Central

    2017-01-01

    Theoretical models of predator–prey systems predict that sufficient enrichment of prey can generate large amplitude limit cycles, paradoxically causing a high risk of extinction (the paradox of enrichment). Although real ecological communities contain many gregarious species, whose foraging behaviour should be influenced by socially transmitted information, few theoretical studies have examined the possibility that social foraging might resolve this paradox. I considered a predator population in which individuals play the producer–scrounger foraging game in one-prey-one-predator and two-prey-one-predator systems. I analysed the stability of a coexisting equilibrium point in the one-prey system and that of non-equilibrium dynamics in the two-prey system. The results revealed that social foraging could stabilize both systems, and thereby resolve the paradox of enrichment when scrounging behaviour (i.e. kleptoparasitism) is prevalent in predators. This suggests a previously neglected mechanism underlying a powerful effect of group-living animals on the sustainability of ecological communities.

  11. One Paradox in District Accountability and Site-Based Management.

    ERIC Educational Resources Information Center

    Shellman, David W.

    The paradox of site-based school management with use of standardized tests or instructional management systems that restrict teacher choices was evident in one school district in North Carolina in which measurement of student success has centered on student performance on state-mandated tests. A study was conducted to see if students whose…

  12. The Paradox of Self-Efficacy: Research with Diverse Populations

    ERIC Educational Resources Information Center

    Lindley, Lori D.

    2006-01-01

    Since its earliest applications to vocational psychology, self-efficacy has been recognized for its utility with diverse populations, attributable to its attention to environmental influences. Somewhat paradoxically, then, it has also been criticized as being limited in its applicability with people from other cultures, because of its focus on…

  13. Achievement Data in IEA Studies and Simpson's Paradox

    ERIC Educational Resources Information Center

    Zuzovsky, Ruth; Steinberg, David M.; Libman, Zipi

    2011-01-01

    This paper is meant to highlight the occurrence of Simpson's Paradox when using aggregated data obtained from two IEA studies in Israel, while ignoring the effect of a powerful intervening variable in the local context--the ethnicity factor. It will demonstrate faulty conclusions regarding either the absence of relationships between a contextual…

  14. A Psychological Taxonomy of Organizational Innovation: Resolving the Paradoxes

    ERIC Educational Resources Information Center

    Cropley, David; Cropley, Arthur

    2012-01-01

    The process of innovation involves numerous contradictions not adequately addressed by business-oriented approaches, in particular the problem that what seem to be mutually antagonistic factors are involved. Psychological research on creativity, especially the 4 "Ps" (process, person, product, and press) and the paradoxes of creativity…

  15. Paradoxes of Learning: On Becoming an Individual in Society.

    ERIC Educational Resources Information Center

    Jarvis, Peter

    This book explores how learning is the lifetime quest to understand personal identity, purpose, and meaning while conforming and adapting to the perceived and real confines of a paradoxical society. It examines the complex social experience of learning, revealing how culture, gender, race, and other societal factors shape and mold an individual's…

  16. Managing Polarity, Paradox, and Dilemma during Leader Transition

    ERIC Educational Resources Information Center

    Manderscheid, Steven V.; Freeman, Peter D.

    2012-01-01

    Purpose: The purpose of this study is to review literature relevant to leader transition and the navigation of polarities, paradoxes, and dilemmas that exist in organizations. Furthermore, the researchers aim to critique the literature and provide suggestions for practitioners and researchers interested in leader transition through the lens of…

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

    ERIC Educational Resources Information Center

    Johnson, Fern L.

    2013-01-01

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

  18. An Apparent Paradox: Catt's Anomaly

    ERIC Educational Resources Information Center

    Pieraccini, M.; Selleri, S.

    2013-01-01

    Catt's anomaly is a sort of "thought experiment" (a "gedankenexperiment") where electrons seem to travel at the speed of light. Although its author argued with conviction for many years, it has a clear and satisfactory solution and it can be considered indubitably just an apparent paradox. Nevertheless, it is curious and…

  19. The Double Cone: A Mechanical Paradox or a Geometrical Constraint?

    ERIC Educational Resources Information Center

    Gallitto, Aurelio Agliolo; Fiordilino, Emilio

    2011-01-01

    In the framework of the Italian National Plan "Lauree Scientifiche" (PLS) in collaboration with secondary schools, we have investigated the mechanical paradox of the double cone. We have calculated the geometric condition for obtaining an upward movement. Based on this result, we have built a mechanical model with a double cone made of aluminum…

  20. Danburite in evaporites of the Paradox basin, Utah.

    USGS Publications Warehouse

    Raup, O.B.; Madsen, B.M.

    1986-01-01

    Danburite (CaB2Si2O8) has been found as nodules in Pennsylvanian age marine evaporites. The occurrence of danburite and its relation to the host rock in the Paradox basin evaporites indicates that it most likely formed by diagenetic reaction of boron-rich, high-salinity brines with constituents in the anhydrite host rock.-from Authors

  1. Understanding Persistent Food Insecurity: A Paradox of Place and Circumstance

    ERIC Educational Resources Information Center

    Mammen, Sheila; Bauer, Jean W.; Richards, Leslie

    2009-01-01

    Survey data from a U.S. Department of Agriculture funded multi-state longitudinal project revealed a paradox where rural low-income families from states considered prosperous were persistently more food insecure than similar families from less prosperous states. An examination of quantitative and qualitative data found that families in the food…

  2. Design principles of paradoxical signaling in the immune system

    NASA Astrophysics Data System (ADS)

    Hart, Yuval

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

  3. On a Simple Formulation of the Golf Ball Paradox

    ERIC Educational Resources Information Center

    Pujol, O.; Perez, J. Ph.

    2007-01-01

    The motion of a ball rolling without slipping on the lateral section inside a fixed vertical cylinder is analysed in the Earth referential frame which is assumed to be Galilean. Equations of motion are rapidly obtained and the golf ball paradox is understood: these equations describe a motion consisting of a vertical harmonic oscillation related…

  4. The "Paradoxical Effect" of Stimulants' Upon Hyperactive Children

    ERIC Educational Resources Information Center

    Brodemus, John; Swanson, Jon C.

    1977-01-01

    Amphetamines and other stimulant drugs are not causing so-called "paradoxical effects" in hyperactive children but are actually effective because they provide needed stimulation. According to the Swanson-Brodemus Model, amphetamines, et al., provide internal sources of stimulation, thus reducing the need for external stimulation. (Author)

  5. Simpson's Paradox in the Interpretation of "Leaky Pipeline" Data

    ERIC Educational Resources Information Center

    Walton, Paul H.; Walton, Daniel J.

    2016-01-01

    The traditional "leaky pipeline" plots are widely used to inform gender equality policy and practice. Herein, we demonstrate how a statistical phenomenon known as Simpson's paradox can obscure trends in gender "leaky pipeline" plots. Our approach has been to use Excel spreadsheets to generate hypothetical "leaky…

  6. Resolving the Paradoxes of Creativity: An Extended Phase Model

    ERIC Educational Resources Information Center

    Cropley, Arthur; Cropley, David

    2008-01-01

    Many teachers are interested in fostering creativity, and there are good reasons for doing so. However, the question of how to do it is made difficult by the paradoxes of creativity: mutually contradictory findings that are, nonetheless, simultaneously true (e.g. convergent thinking hampers creativity but is also necessary for it). These paradoxes…

  7. Apparent Paradoxes in Classical Electrodynamics: Relativistic Transformation of Force

    ERIC Educational Resources Information Center

    Kholmetskii, A. L.; Yarman, T.

    2007-01-01

    In this paper, we analyse a number of paradoxical teaching problems of classical electrodynamics, dealing with the relativistic transformation of force for complex macro systems, consisting of a number of subsystems with nonzero relative velocities such as electric circuits that change their shape in the course of time. (Contains 7 figures.)

  8. Paradoxes in Higher Education: Universities versus Academic Colleges

    ERIC Educational Resources Information Center

    Davidovitch, Nitza; Sinuany-Stern, Zilla; Iram, Yaacov

    2013-01-01

    This article deals with paradoxical relationships between Israeli universities and colleges and their effect on the system of higher education. The article analyzes the history of the higher-education discourse, ranging from patronizing and domineering relations to collaboration based on the recognition that Israel's entire system of higher…

  9. Paradoxical Prescriptions in Family Therapy: From Child to Marital Focus.

    ERIC Educational Resources Information Center

    Protinsky, Howard; And Others

    1982-01-01

    Proposes a technique using paradoxical prescription with families to successfully move away from the identified patient to an emphasis on family and marital dynamics. Presents three clinical illustrations to demonstrate the procedure. Poses some research questions regarding the use of this technique and the need for further refinement. (Author)

  10. Detecting weakly interacting massive particles.

    NASA Astrophysics Data System (ADS)

    Drukier, A. K.; Gelmini, G. B.

    The growing synergy between astrophysics, particle physics, and low background experiments strengthens the possibility of detecting astrophysical non-baryonic matter. The idea of direct detection is that an incident, massive weakly interacting particle could collide with a nucleus and transfer an energy that could be measured. The present low levels of background achieved by the PNL/USC Ge detector represent a new technology which yields interesting bounds on Galactic cold dark matter and on light bosons emitted from the Sun. Further improvements require the development of cryogenic detectors. The authors analyse the practicality of such detectors, their optimalization and background suppression using the "annual modulation effect".

  11. Solid holography and massive gravity

    NASA Astrophysics Data System (ADS)

    Alberte, Lasma; Baggioli, Matteo; Khmelnitsky, Andrei; Pujolàs, Oriol

    2016-02-01

    Momentum dissipation is an important ingredient in condensed matter physics that requires a translation breaking sector. In the bottom-up gauge/gravity duality, this implies that the gravity dual is massive. We start here a systematic analysis of holographic massive gravity (HMG) theories, which admit field theory dual interpretations and which, therefore, might store interesting condensed matter applications. We show that there are many phases of HMG that are fully consistent effective field theories and which have been left overlooked in the literature. The most important distinction between the different HMG phases is that they can be clearly separated into solids and fluids. This can be done both at the level of the unbroken spacetime symmetries as well as concerning the elastic properties of the dual materials. We extract the modulus of rigidity of the solid HMG black brane solutions and show how it relates to the graviton mass term. We also consider the implications of the different HMGs on the electric response. We show that the types of response that can be consistently described within this framework is much wider than what is captured by the narrow class of models mostly considered so far.

  12. Gas in Hepatic Portal Veins with Gastric Massive Dilatation and Pneumatosis in Acute Pancreatitis

    PubMed Central

    Mushtaq, Nadeem; Pateria, Vibhor; Ahmad, Imtiyaz; Kulshreshtha, Nitin

    2015-01-01

    Gas in portal veins is a rare phenomenon observed secondary to bowel ischaemia and necrosis. A young girl with history of pica ingestion presented with acute abdomen with huge distension. Investigation revealed air in hepatic portal veins, air within stomach wall, and massive distension of stomach secondary to acute pancreatitis. Successful conservative treatment confirmed the current concept that all cases of hepatic portal venous gas do not warrant immediate surgical intervention. PMID:26557565

  13. PRISM Polarimetry of Massive Stars

    NASA Astrophysics Data System (ADS)

    Kerkstra, Brennan; Lomax, Jamie R.; Bjorkman, Karen S.; Bjorkman, Jon Eric; Skiff, Brian; Covey, Kevin R.; Wisniewski, John P.

    2016-01-01

    We present the early results from our long-term, multi-epoch filter polarization survey of massive stars in and around young Galactic clusters. These BVRI polarization data were obtained using the PRISM instrument mounted on the 1.8m Perkins Telescope at Lowell Observatory. We first detail the creation of our new semi-automated polarization data reduction pipeline that we developed to process these data. Next, we present our analysis of the instrumental polarization properties of the PRISM instrument, via observations of polarized and unpolarized standard stars. Finally, we present early results on the total and intrinsic polarization behavior of several isolated, previously suggested classical Be stars, and discuss these results in the context of the larger project.BK acknowledges support from a NSF/REU at the University of Oklahoma. This program was also supported by NSF-AST 11411563, 1412110, and 1412135.

  14. Merlin - Massively parallel heterogeneous computing

    NASA Technical Reports Server (NTRS)

    Wittie, Larry; Maples, Creve

    1989-01-01

    Hardware and software for Merlin, a new kind of massively parallel computing system, are described. Eight computers are linked as a 300-MIPS prototype to develop system software for a larger Merlin network with 16 to 64 nodes, totaling 600 to 3000 MIPS. These working prototypes help refine a mapped reflective memory technique that offers a new, very general way of linking many types of computer to form supercomputers. Processors share data selectively and rapidly on a word-by-word basis. Fast firmware virtual circuits are reconfigured to match topological needs of individual application programs. Merlin's low-latency memory-sharing interfaces solve many problems in the design of high-performance computing systems. The Merlin prototypes are intended to run parallel programs for scientific applications and to determine hardware and software needs for a future Teraflops Merlin network.

  15. Derivative couplings in massive bigravity

    SciTech Connect

    Gao, Xian; Heisenberg, Lavinia E-mail: lavinia.heisenberg@eth-its.ethz.ch

    2016-03-01

    In this work we study the cosmological perturbations in massive bigravity in the presence of non-minimal derivative couplings. For this purpose we consider a specific subclass of Horndeski scalar-tensor interactions that live on the unique composite effective metric. For the viability of the model both metrics have to be dynamical. Nevertheless, the number of allowed kinetic terms is crucial. We adapt to the restriction of having one single kinetic term. After deriving the full set of equations of motion for flat Friedmann-Lemaitre-Robertson-Walker background, we study linear perturbations on top of it. We show explicitly that only four tensor, two vector and two scalar degrees of freedom propagate, one of which being the Horndeski scalar, while the Boulware-Deser ghost can be integrated out.

  16. BFKL Pomeron with massive gluons

    NASA Astrophysics Data System (ADS)

    Levin, Eugene; Lipatov, Lev; Siddikov, Marat

    2014-04-01

    We solve the BFKL equation in the leading logarithmic approximation numerically in the Yang-Mills theory with the Higgs mechanism for the vector boson mass generation. It can be considered as a model for the amplitude with the correct behavior of the s-channel partial waves at large impact parameters. The Pomeron spectrum of the massive BFKL kernel in the ω space for t=0 coincides with the continuous spectrum for the massless case although the density of its eigenvalues is 2 times smaller for ω>ω0, where ω0 is a negative number. We find a simple parametrization for the corresponding eigenfunctions. Because the leading singularity in the ω plane in this Higgs model for t=0 is a fixed cut, the Regge pole contributions could be only for nonphysical positive t. Hence we can state that the correct behavior at large b does not influence the main properties of the BFKL equation.

  17. Massively Parallel MRI Detector Arrays

    PubMed Central

    Keil, Boris; Wald, Lawrence L

    2013-01-01

    Originally proposed as a method to increase sensitivity by extending the locally high-sensitivity of small surface coil elements to larger areas, the term parallel imaging now includes the use of array coils to perform image encoding. This methodology has impacted clinical imaging to the point where many examinations are performed with an array comprising multiple smaller surface coil elements as the detector of the MR signal. This article reviews the theoretical and experimental basis for the trend towards higher channel counts relying on insights gained from modeling and experimental studies as well as the theoretical analysis of the so-called “ultimate” SNR and g-factor. We also review the methods for optimally combining array data and changes in RF methodology needed to construct massively parallel MRI detector arrays and show some examples of state-of-the-art for highly accelerated imaging with the resulting highly parallel arrays. PMID:23453758

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

    USGS Publications Warehouse

    Hite, R.J.; Lohman, Stanley William

    1973-01-01

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

  19. Privacy Awareness: A Means to Solve the Privacy Paradox?

    NASA Astrophysics Data System (ADS)

    Pötzsch, Stefanie

    People are limited in their resources, i.e. they have limited memory capabilities, cannot pay attention to too many things at the same time, and forget much information after a while; computers do not suffer from these limitations. Thus, revealing personal data in electronic communication environments and being completely unaware of the impact of privacy might cause a lot of privacy issues later. Even if people are privacy aware in general, the so-called privacy paradox shows that they do not behave according to their stated attitudes. This paper discusses explanations for the existing dichotomy between the intentions of people towards disclosure of personal data and their behaviour. We present requirements on tools for privacy-awareness support in order to counteract the privacy paradox.

  20. Paradoxes of Personal Responsibility in Mental Health Care.

    PubMed

    Lakeman, Richard

    2016-12-01

    Personal responsibility is widely considered important in mental health recovery as well as in popular models of alcohol and drug treatment. Neo-liberal socio-political rhetoric around consumerism in health care often assumes that people are informed and responsible for their own choices and behaviour. In the mental health care context and especially in emergency or crisis settings, personal responsibility often raises particular paradoxes. People often present whose behaviour does not conform to the ideals of the responsible consumer; they may seek and/or be granted absolution from irresponsible behaviour. This paradox is explored and clinicians are urged to consider the context-bound nature of personal responsibility and how attributions of personal responsibility may conflict with policy and their own professional responsibilities to intervene to protect others.

  1. Inductive reasoning and judgment interference: experiments on Simpson's paradox.

    PubMed

    Fiedler, Klaus; Walther, Eva; Freytag, Peter; Nickel, Stefanie

    2003-01-01

    In a series of experiments on inductive reasoning, participants assessed the relationship between gender, success, and a covariate in a situation akin to Simpson's paradox: Although women were less successful then men according to overall statistics, they actually fared better then men at either of two universities. Understanding trivariate relationships of this kind requires cognitive routines similar to analysis of covariance. Across the first five experiments, however, participants generalized the disadvantage of women at the aggregate level to judgments referring to the different levels of the covariate, even when motivation was high and appropriate mental models were activated. The remaining three experiments demonstrated that Simpson's paradox could be mastered when the salience of the covariate was increased and when the salience of gender was decreased by the inclusion of temporal cues that disambiguate the causal status of the covariate.

  2. Ribosomopathies and the paradox of cellular hypo- to hyperproliferation

    PubMed Central

    Sulima, Sergey O.; Dinman, Jonathan D.

    2015-01-01

    Ribosomopathies are largely congenital diseases linked to defects in ribosomal proteins or biogenesis factors. Some of these disorders are characterized by hypoproliferative phenotypes such as bone marrow failure and anemia early in life, followed by elevated cancer risks later in life. This transition from hypo- to hyperproliferation presents an intriguing paradox in the field of hematology known as “Dameshek’s riddle.” Recent cancer sequencing studies also revealed somatically acquired mutations and deletions in ribosomal proteins in T-cell acute lymphoblastic leukemia and solid tumors, further extending the list of ribosomopathies and strengthening the association between ribosomal defects and oncogenesis. In this perspective, we summarize and comment on recent findings in the field of ribosomopathies. We explain how ribosomopathies may provide clues to help explain Dameshek’s paradox and highlight some of the open questions and challenges in the field. PMID:25575543

  3. How River Rocks Round: Resolving the Shape-Size Paradox

    PubMed Central

    Domokos, Gabor; Jerolmack, Douglas J.; Sipos, Andras Á.; Török, Ákos

    2014-01-01

    River-bed sediments display two universal downstream trends: fining, in which particle size decreases; and rounding, where pebble shapes evolve toward ellipsoids. Rounding is known to result from transport-induced abrasion; however many researchers argue that the contribution of abrasion to downstream fining is negligible. This presents a paradox: downstream shape change indicates substantial abrasion, while size change apparently rules it out. Here we use laboratory experiments and numerical modeling to show quantitatively that pebble abrasion is a curvature-driven flow problem. As a consequence, abrasion occurs in two well-separated phases: first, pebble edges rapidly round without any change in axis dimensions until the shape becomes entirely convex; and second, axis dimensions are then slowly reduced while the particle remains convex. Explicit study of pebble shape evolution helps resolve the shape-size paradox by reconciling discrepancies between laboratory and field studies, and enhances our ability to decipher the transport history of a river rock. PMID:24533132

  4. How river rocks round: resolving the shape-size paradox.

    PubMed

    Domokos, Gabor; Jerolmack, Douglas J; Sipos, Andras Á; Török, Akos

    2014-01-01

    River-bed sediments display two universal downstream trends: fining, in which particle size decreases; and rounding, where pebble shapes evolve toward ellipsoids. Rounding is known to result from transport-induced abrasion; however many researchers argue that the contribution of abrasion to downstream fining is negligible. This presents a paradox: downstream shape change indicates substantial abrasion, while size change apparently rules it out. Here we use laboratory experiments and numerical modeling to show quantitatively that pebble abrasion is a curvature-driven flow problem. As a consequence, abrasion occurs in two well-separated phases: first, pebble edges rapidly round without any change in axis dimensions until the shape becomes entirely convex; and second, axis dimensions are then slowly reduced while the particle remains convex. Explicit study of pebble shape evolution helps resolve the shape-size paradox by reconciling discrepancies between laboratory and field studies, and enhances our ability to decipher the transport history of a river rock.

  5. The Critical Care Obesity Paradox and Implications for Nutrition Support.

    PubMed

    Patel, Jayshil J; Rosenthal, Martin D; Miller, Keith R; Codner, Panna; Kiraly, Laszlo; Martindale, Robert G

    2016-09-01

    Obesity is a leading cause of preventable death worldwide. The prevalence of obesity has been increasing and is associated with an increased risk for other co-morbidities. In the critical care setting, nearly one third of patients are obese. Obese critically ill patients pose significant physical and on-physical challenges to providers, including optimization of nutrition therapy. Intuitively, obese patients would have worse critical care-related outcome. On the contrary, emerging data suggests that critically ill obese patients have improved outcomes, and this phenomenon has been coined "the obesity paradox." The purposes of this review will be to outline the historical views and pathophysiology of obesity and epidemiology of obesity, describe the challenges associated with obesity in the intensive care unit setting, review critical care outcomes in the obese, define the obesity-critical care paradox, and identify the challenges and role of nutrition support in the critically ill obese patient.

  6. Einstein-Podolsky-Rosen Paradox in Twin Images

    NASA Astrophysics Data System (ADS)

    Moreau, Paul-Antoine; Devaux, Fabrice; Lantz, Eric

    2014-10-01

    Spatially entangled twin photons provide both promising resources for modern quantum information protocols, because of the high dimensionality of transverse entanglement, and a test of the Einstein-Podolsky-Rosen paradox in its original form of position versus impulsion. Usually, photons in temporal coincidence are selected and their positions recorded, resulting in a priori assumptions on their spatiotemporal behavior. In this Letter, we record, on two separate electron-multiplying charge coupled devices cameras, twin images of the entire flux of spontaneous down-conversion. This ensures a strict equivalence between the subsystems corresponding to the detection of either position (image or near-field plane) or momentum (Fourier or far-field plane). We report the highest degree of paradox ever reported and show that this degree corresponds to the number of independent degrees of freedom, or resolution cells, of the images.

  7. Einstein-Podolsky-Rosen paradox in twin images.

    PubMed

    Moreau, Paul-Antoine; Devaux, Fabrice; Lantz, Eric

    2014-10-17

    Spatially entangled twin photons provide both promising resources for modern quantum information protocols, because of the high dimensionality of transverse entanglement, and a test of the Einstein-Podolsky-Rosen paradox in its original form of position versus impulsion. Usually, photons in temporal coincidence are selected and their positions recorded, resulting in a priori assumptions on their spatiotemporal behavior. In this Letter, we record, on two separate electron-multiplying charge coupled devices cameras, twin images of the entire flux of spontaneous down-conversion. This ensures a strict equivalence between the subsystems corresponding to the detection of either position (image or near-field plane) or momentum (Fourier or far-field plane). We report the highest degree of paradox ever reported and show that this degree corresponds to the number of independent degrees of freedom, or resolution cells, of the images.

  8. Does massive intraabdominal free gas require surgical intervention?

    PubMed Central

    Furihata, Tadashi; Furihata, Makoto; Ishikawa, Kunibumi; Kosaka, Masato; Satoh, Naoki; Kubota, Keiichi

    2016-01-01

    We describe a rare case of an 81-year-old man who presented with severe epigastralgia. A chest radiograph showed massive free gas bilaterally in the diaphragmatic spaces. Computed tomography (CT) scan also showed massive free gas in the peritoneal cavity with portal venous gas. We used a wait-and-see approach and carefully considered surgery again when the time was appropriate. The patient received conservative therapy with fasting, an intravenous infusion of antibiotics, and nasogastric intubation. The patient soon recovered and was able to start eating meals 4 d after treatment; thus, surgical intervention was avoided. Thereafter, colonoscopy examination showed pneumatosis cystoides intestinalis in the ascending colon. On retrospective review, CT scan demonstrated sporadic air-filled cysts in the ascending colon. The present case taught us a lesson: the presence of massive intraabdominal free gas with portal venous gas does not necessarily require surgical intervention. Pneumatosis cystoides intestinalis should be considered as a potential causative factor of free gas with portal venous gas when making the differential diagnosis. PMID:27621584

  9. A Paradoxical Evolutionary Mechanism in Stochastically Switching Environments

    PubMed Central

    Cheong, Kang Hao; Tan, Zong Xuan; Xie, Neng-gang; Jones, Michael C.

    2016-01-01

    Organisms with environmental sensors that guide survival are considered more likely to be favored by natural selection if they possess more accurate sensors. In this paper, we develop a theoretical model which shows that under certain conditions of environmental stochasticity, selection actually favors sensors of lower accuracy. An analogy between this counter-intuitive phenomenon and the well-known Parrondo’s paradox is suggested. PMID:27739447

  10. Security Assistance in Latin America: Paradox and Dilemma

    DTIC Science & Technology

    1991-06-21

    the Third World." Parameters, March 1990, pp. 38-47. Starr, Richard F., ed. Yearbook on International Communist Affairs. Stanford: Hoover Institutional...distribuition is unlinuited 4. PERFPORMING ORGANIZATION REPORT NUMIER( S ) S MONITORING ORGANIZATION REPORT NUMBER( S ) 69. NAME OF PERFORMING ORGANIZATION...11. TITLE (bnckud Secuity Clawficationy SECURITY ASSISTANCE IN LATIN AMERICA: PARADOX AND DILEMNA (UNCLASSIFIED) 12. PERSONAL AUTHOR( S ) iKAJOR ROBERT

  11. Molecular Pathological Epidemiology Gives Clues to Paradoxical Findings

    PubMed Central

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

    2015-01-01

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

  12. Resolution of the Klein Paradox within Relativistic Quantum Mechanics

    SciTech Connect

    Alhaidari, A. D.

    2011-10-27

    We present a resolution of the Klein paradox within the framework of one-particle relativistic quantum mechanics (no pair production). Not only reflection becomes total but the vacuum remains neutral as well. This is accomplished by replacing the pair production process with virtual negative energy ''incidence'' within the barrier in a process analogous to the introduction of image charges in electrostatic and virtual sources in optics.

  13. North Korean Paradoxes. Circumstances, Costs, and Consequences of Korean Unification

    DTIC Science & Technology

    2005-01-01

    paper) 1. Korean reunification question (1945- ) 2. Korea (North)-Economic policy. 3. Korea (North)--Politics and government. 4. Security, International...order@rand.org Preface This monograph, focusing on North Korea , analyzes some of the economic, political, and security issues associated with Korean ...Northeast Asia. iii iv North Korean Paradoxes This research was performed within the International Security and Defense Policy Center of the RAND National

  14. Paradoxes in medicine: an access to new knowledge?

    PubMed

    Ginter, E; Simko, V; Dolinska, S

    2009-01-01

    The analysis of health and nutrition data from various countries shows many surprising and seemingly incomprehensible facts and paradoxical relationships. Health status of a country is the result of long-term factors and therefore it cannot be changed from day to day. For example in Central European countries there was a sudden increase in life expectancy after the fall of Soviet hegemony. French paradox is the oldest example of apparent contrast between "unhealthy" nutrition and low cardiovascular mortality. Although, the consumption of animal fat and milk and milk products in Switzerland is very high, but premature cardiovascular mortality of Swiss men and women is the lowest in Europe. In USA there is concominant increase of obesity and decrease in cardiovascular mortality. In Cuba, in spite of great economic problems its relatively high male and female life expectancy is very similar to the rich USA. The life expectancy in Albania is significantly higher than in many countries in Central Europe and in the Balkan region, in spite of the fact that Albania remains the poorest European country. Analysis of these unexpected and paradoxical relations indicate the importance of the quality of medical care, control of cardiovascular risk factors (USA) and the influence of modest but biologically balanced diet on low prevalence of cardiovascular disease in Cuba and Albania. The experience from former communist Central European countries suggests important influence of chronic stress and psychosocial factors on heart diseases and life expectancy. These paradoxes open the door to new information (Fig. 5, Ref. 11). Full Text (Free, PDF) www.bmj.sk.

  15. Myasthenia Gravis: paradox versus paradigm in autoimmunity.

    PubMed

    Berrih-Aknin, Sonia

    2014-08-01

    Myasthenia Gravis (MG) is a paradigm of organ-specific autoimmune disease (AID). It is mediated by antibodies that target the neuromuscular junction. The purpose of this review is to place MG in the general context of autoimmunity, to summarize the common mechanisms between MG and other AIDs, and to describe the specific mechanisms of MG. We have chosen the most common organ-specific AIDs to compare with MG: type 1 diabetes mellitus (T1DM), autoimmune thyroid diseases (AITD), multiple sclerosis (MS), some systemic AIDs (systemic lupus erythematous (SLE), rheumatoid arthritis (RA), Sjogren's syndrome (SS)), as well as inflammatory diseases of the gut and liver (celiac disease (CeD), Crohn's disease (CD), and primary biliary cirrhosis (PBC)). Several features are similar between all AIDs, suggesting that common pathogenic mechanisms lead to their development. In this review, we address the predisposing factors (genetic, epigenetic, hormones, vitamin D, microbiota), the triggering components (infections, drugs) and their interactions with the immune system [1,2]. The dysregulation of the immune system is detailed and includes the role of B cells, Treg cells, Th17 and cytokines. We particularly focused on the role of TNF-α and interferon type I whose role in MG is very analogous to that in several other AIDS. The implication of AIRE, a key factor in central tolerance is also discussed. Finally, if MG is a prototype of AIDS, it has a clear specificity compared to the other AIDS, by the fact that the target organ, the muscle, is not the site of immune infiltration and B cell expansion, but exclusively that of antibody-mediated pathogenic mechanisms. By contrast, the thymus in the early onset subtype frequently undergoes tissue remodeling, resulting in the development of ectopic germinal centers surrounded by high endothelial venules (HEV), as observed in the target organs of many other AIDs.

  16. Paradoxical pharmacology: turning our pharmacological models upside down.

    PubMed

    Page, Clive

    2011-04-01

    Paradoxical pharmacology is a term first suggested by Richard Bond to refer to intriguing observations that chronic use of some drug types can have the opposite biological effect(s) to those seen following acute administration of the same drug. A good example of 'paradoxical pharmacology' is the research Richard has pioneered showing that whereas acute administration of β-blockers is contraindicated in the treatment of asthma, chronic use of certain β-blockers can have therapeutic benefit. It would appear that those β-blockers that can act as inverse agonists at the β2 receptor particularly show this paradoxical effect and the findings of Richard's research not only challenge the dogma of the treatment of asthma but also challenge many of the pharmacological principles of ligand/receptor interactions established by Sir James Black and others. In this paper, I discuss Richard's efforts to evaluate the chronic effects of β-blockers in the airways and how this research caught the imagination of Sir James Black.

  17. Paradoxical vocal cord dysfunction: clinical experience and personal considerations.

    PubMed

    Nacci, A; Fattori, B; Ursino, F; Rocchi, V; Matteucci, F; Citi, C; Bruschini, L; Rognini, F; La Vela, R; Dallan, I

    2007-10-01

    Paradoxical vocal cord dysfunction is a nosographic entity that remains to be fully elucidated as far as concerns criteria required for diagnosis and underlying aetiopathogenesis. The disorder manifests with repeated episodes of acute dyspnoea associated with a series of symptoms that may include hoarseness, globus, chest pain and "shortness of breath". A retrospective analysis of cases with acute dyspnoea referred to our Department between June 2004 and June 2005 revealed 3 patients with paradoxical vocal cord dysfunction. In 2 of these 3 cases, concomitant psychiatric morbidity was observed and the third also presented gastro-oesophageal reflux. In one patient, the episodes of dyspnoea were triggered by inspiration of irritating substances. Diagnosis of the condition requires a high level of suspicion, which is confirmed by a laryngoscopic investigation that demonstrates hyperadduction of the true vocal cords and a reduction of at least 50% in the breathing space. From a therapeutic point of view, patients with paradoxical vocal cord dysfunction require, in our opinion, a multidisciplinary approach; in fact, only a team comprising otorhinolaryngologists, phoniatricians, pulmonologists, neurologists, allergologists, psychotherapists and speech therapists is capable of defining the appropriate treatment according to the clinical and psychological characteristics of each individual patient. Our results with speech therapy, focused on respiratory and speech retraining, are reported.

  18. Paradoxical signaling regulates structural plasticity in dendritic spines

    PubMed Central

    Rangamani, Padmini; Levy, Michael G.; Khan, Shahid; Oster, George

    2016-01-01

    Transient spine enlargement (3- to 5-min timescale) is an important event associated with the structural plasticity of dendritic spines. Many of the molecular mechanisms associated with transient spine enlargement have been identified experimentally. Here, we use a systems biology approach to construct a mathematical model of biochemical signaling and actin-mediated transient spine expansion in response to calcium influx caused by NMDA receptor activation. We have identified that a key feature of this signaling network is the paradoxical signaling loop. Paradoxical components act bifunctionally in signaling networks, and their role is to control both the activation and the inhibition of a desired response function (protein activity or spine volume). Using ordinary differential equation (ODE)-based modeling, we show that the dynamics of different regulators of transient spine expansion, including calmodulin-dependent protein kinase II (CaMKII), RhoA, and Cdc42, and the spine volume can be described using paradoxical signaling loops. Our model is able to capture the experimentally observed dynamics of transient spine volume. Furthermore, we show that actin remodeling events provide a robustness to spine volume dynamics. We also generate experimentally testable predictions about the role of different components and parameters of the network on spine dynamics. PMID:27551076

  19. Cutaneous wound healing through paradoxical MAPK activation by BRAF inhibitors

    PubMed Central

    Escuin-Ordinas, Helena; Li, Shuoran; Xie, Michael W.; Sun, Lu; Hugo, Willy; Huang, Rong Rong; Jiao, Jing; de-Faria, Felipe Meira; Realegeno, Susan; Krystofinski, Paige; Azhdam, Ariel; Komenan, Sara Marie D.; Atefi, Mohammad; Comin-Anduix, Begoña; Pellegrini, Matteo; Cochran, Alistair J.; Modlin, Robert L.; Herschman, Harvey R.; Lo, Roger S.; McBride, William H.; Segura, Tatiana; Ribas, Antoni

    2016-01-01

    BRAF inhibitors are highly effective therapies for the treatment of BRAFV600-mutated melanoma, with the main toxicity being a variety of hyperproliferative skin conditions due to paradoxical activation of the mitogen-activated protein kinase (MAPK) pathway in BRAF wild-type cells. Most of these hyperproliferative skin changes improve when a MEK inhibitor is co-administered, as it blocks paradoxical MAPK activation. Here we show how the BRAF inhibitor vemurafenib accelerates skin wound healing by inducing the proliferation and migration of human keratinocytes through extracellular signal-regulated kinase (ERK) phosphorylation and cell cycle progression. Topical treatment with vemurafenib in two wound-healing mice models accelerates cutaneous wound healing through paradoxical MAPK activation; addition of a mitogen-activated protein kinase kinase (MEK) inhibitor reverses the benefit of vemurafenib-accelerated wound healing. The same dosing regimen of topical BRAF inhibitor does not increase the incidence of cutaneous squamous cell carcinomas in mice. Therefore, topical BRAF inhibitors may have clinical applications in accelerating the healing of skin wounds. PMID:27476449

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  1. Implications of Stein's Paradox for Environmental Standard Compliance Assessment.

    PubMed

    Qian, Song S; Stow, Craig A; Cha, YoonKyung

    2015-05-19

    The implications of Stein's paradox stirred considerable debate in statistical circles when the concept was first introduced in the 1950s. The paradox arises when we are interested in estimating the means of several variables simultaneously. In this situation, the best estimator for an individual mean, the sample average, is no longer the best. Rather, a shrinkage estimator, which shrinks individual sample averages toward the overall average is shown to have improved overall accuracy. Although controversial at the time, the concept of shrinking toward overall average is now widely accepted as a good practice for improving statistical stability and reducing error, not only in simple estimation problems, but also in complicated modeling problems. However, the utility of Stein's insights are not widely recognized in the environmental management community, where mean pollutant concentrations of multiple waters are routinely estimated for management decision-making. In this essay, we introduce Stein's paradox and its modern generalization, the Bayesian hierarchical model, in the context of environmental standard compliance assessment. Using simulated data and nutrient monitoring data from wadeable streams around the Great Lakes, we show that a Bayesian hierarchical model can improve overall estimation accuracy, thereby improving our confidence in the assessment results, especially for standard compliance assessment of waters with small sample sizes.

  2. Revealing the paradox of drug reward in human evolution

    PubMed Central

    Sullivan, Roger J; Hagen, Edward H; Hammerstein, Peter

    2008-01-01

    Neurobiological models of drug abuse propose that drug use is initiated and maintained by rewarding feedback mechanisms. However, the most commonly used drugs are plant neurotoxins that evolved to punish, not reward, consumption by animal herbivores. Reward models therefore implicitly assume an evolutionary mismatch between recent drug-profligate environments and a relatively drug-free past in which a reward centre, incidentally vulnerable to neurotoxins, could evolve. By contrast, emerging insights from plant evolutionary ecology and the genetics of hepatic enzymes, particularly cytochrome P450, indicate that animal and hominid taxa have been exposed to plant toxins throughout their evolution. Specifically, evidence of conserved function, stabilizing selection, and population-specific selection of human cytochrome P450 genes indicate recent evolutionary exposure to plant toxins, including those that affect animal nervous systems. Thus, the human propensity to seek out and consume plant neurotoxins is a paradox with far-reaching implications for current drug-reward theory. We sketch some potential resolutions of the paradox, including the possibility that humans may have evolved to counter-exploit plant neurotoxins. Resolving the paradox of drug reward will require a synthesis of ecological and neurobiological perspectives of drug seeking and use. PMID:18353749

  3. Authority as paradox: the transformations of Don Quijote.

    PubMed

    Priel, Beatriz

    2006-12-01

    The author's contention is that the analysand's temporary attribution of authority to the analyst is inherent in the analytic situation; this is seen as a transitional and paradoxical form of authority pertaining neither to internal nor external reality, but dwelling in the analytic third. The author proposes a conceptualization of psychoanalytic authority as a form of aesthetic authority according to Gadamer's definitions. While the scientific and hermeneutic codes for the understanding of authority in psychoanalysis assume that the main issue at stake is the delimitation of the objectivity or the subjectivity of the analyst's knowledge, this aesthetic perspective centres on the analysand's attribution of a claim of truth to analytic interpretations, and on the experience of recognition. The experience of recognition of a possible truth is particular and context-bound, as well as self-transformational. A reading of three episodes from Cervantes's The history of Don Quixote de la Mancha illuminates the transitional and paradoxical character of aesthetic authority within a transformational dialogue. These episodes are read as dramatizations of different positions vis-à-vis the paradoxical authority that characterizes transformational dialogues.

  4. A metabolic perspective of Peto's paradox and cancer

    PubMed Central

    Dang, Chi V.

    2015-01-01

    The frequency of cancer is postulated to be proportional to the number of cells an animal possesses, as each cell is similarly exposed to mutagens with every cell division. Larger animals result from more cell divisions with more mutagenic exposure, and hence are expected to have higher frequencies of cancer. Yet, as stipulated by Peto's paradox, larger animals do not have the higher rates of cancers seen in smaller animals despite the significant differences in cell numbers and a longer lifetime that would expose larger animals to more mutagens. The rates of cancer appear to be inversely proportional to animal body size, which scales inversely with specific metabolic rates of mammals. Studies over the past 20 years have linked oncogenes and tumour suppressors to alterations in cancer metabolism, and conversely, mutations in metabolic genes have been documented to trigger tumorigenesis. The by-products and intermediates of metabolism, such as reactive oxygen species, oxoglutarate, citrate and acetate, all have the potential to mutate and alter the genome or epigenome. On the basis of these general observations, it is proposed that metabolic rates correlate with mutagenic rates, which are higher in small animals and give the mechanistic basis for Peto's paradox. The observations discussed in this overview collectively indicate that specific metabolic rate varies inversely with body size, which seems to support the hypothesis that metabolism drives tumorigenesis and accounts for Peto's paradox. PMID:26056367

  5. Braess paradox in a network of totally asymmetric exclusion processes

    NASA Astrophysics Data System (ADS)

    Bittihn, Stefan; Schadschneider, Andreas

    2016-12-01

    We study the Braess paradox in the transport network as originally proposed by Braess with totally asymmetric exclusion processes (TASEPs) on the edges. The Braess paradox describes the counterintuitive situation in which adding an edge to a road network leads to a user optimum with higher travel times for all network users. Travel times on the TASEPs are nonlinear in the density, and jammed states can occur due to the microscopic exclusion principle, leading to a more realistic description of trafficlike transport on the network than in previously studied linear macroscopic mathematical models. Furthermore, the stochastic dynamics allows us to explore the effects of fluctuations on network performance. We observe that for low densities, the added edge leads to lower travel times. For slightly higher densities, the Braess paradox occurs in its classical sense. At intermediate densities, strong fluctuations in the travel times dominate the system's behavior due to links that are in a domain-wall state. At high densities, the added link leads to lower travel times. We present a phase diagram that predicts the system's state depending on the global density and crucial path-length ratios.

  6. Air Research

    EPA Pesticide Factsheets

    EPA's air research provides the critical science to develop and implement outdoor air regulations under the Clean Air Act and puts new tools and information in the hands of air quality managers and regulators to protect the air we breathe.

  7. Massive Star Burps, Then Explodes

    NASA Astrophysics Data System (ADS)

    2007-04-01

    Berkeley -- In a galaxy far, far away, a massive star suffered a nasty double whammy. On Oct. 20, 2004, Japanese amateur astronomer Koichi Itagaki saw the star let loose an outburst so bright that it was initially mistaken for a supernova. The star survived, but for only two years. On Oct. 11, 2006, professional and amateur astronomers witnessed the star actually blowing itself to smithereens as Supernova 2006jc. Swift UVOT Image Swift UVOT Image (Credit: NASA / Swift / S.Immler) "We have never observed a stellar outburst and then later seen the star explode," says University of California, Berkeley, astronomer Ryan Foley. His group studied the event with ground-based telescopes, including the 10-meter (32.8-foot) W. M. Keck telescopes in Hawaii. Narrow helium spectral lines showed that the supernova's blast wave ran into a slow-moving shell of material, presumably the progenitor's outer layers ejected just two years earlier. If the spectral lines had been caused by the supernova's fast-moving blast wave, the lines would have been much broader. artistic rendering This artistic rendering depicts two years in the life of a massive blue supergiant star, which burped and spewed a shell of gas, then, two years later, exploded. When the supernova slammed into the shell of gas, X-rays were produced. (Credit: NASA/Sonoma State Univ./A.Simonnet) Another group, led by Stefan Immler of NASA's Goddard Space Flight Center, Greenbelt, Md., monitored SN 2006jc with NASA's Swift satellite and Chandra X-ray Observatory. By observing how the supernova brightened in X-rays, a result of the blast wave slamming into the outburst ejecta, they could measure the amount of gas blown off in the 2004 outburst: about 0.01 solar mass, the equivalent of about 10 Jupiters. "The beautiful aspect of our SN 2006jc observations is that although they were obtained in different parts of the electromagnetic spectrum, in the optical and in X-rays, they lead to the same conclusions," says Immler. "This

  8. Battling Arrow's Paradox to Discover Robust Water Management Alternatives

    NASA Astrophysics Data System (ADS)

    Kasprzyk, J. R.; Reed, P. M.; Hadka, D.

    2013-12-01

    This study explores whether or not Arrow's Impossibility Theorem, a theory of social choice, affects the formulation of water resources systems planning problems. The theorem discusses creating an aggregation function for voters choosing from more than three alternatives for society. The Impossibility Theorem is also called Arrow's Paradox, because when trying to add more voters, a single individual's preference will dictate the optimal group decision. In the context of water resources planning, our study is motivated by recent theoretical work that has generalized the insights for Arrow's Paradox to the design of complex engineered systems. In this framing of the paradox, states of society are equivalent to water planning or design alternatives, and the voters are equivalent to multiple planning objectives (e.g. minimizing cost or maximizing performance). Seen from this point of view, multi-objective water planning problems are functionally equivalent to the social choice problem described above. Traditional solutions to such multi-objective problems aggregate multiple performance measures into a single mathematical objective. The Theorem implies that a subset of performance concerns will inadvertently dictate the overall design evaluations in unpredictable ways using such an aggregation. We suggest that instead of aggregation, an explicit many-objective approach to water planning can help overcome the challenges posed by Arrow's Paradox. Many-objective planning explicitly disaggregates measures of performance while supporting the discovery of the planning tradeoffs, employing multiobjective evolutionary algorithms (MOEAs) to find solutions. Using MOEA-based search to address Arrow's Paradox requires that the MOEAs perform robustly with increasing problem complexity, such as adding additional objectives and/or decisions. This study uses comprehensive diagnostic evaluation of MOEA search performance across multiple problem formulations (both aggregated and many

  9. Remark on massive particle's de Sitter tunneling

    SciTech Connect

    Jiang, Qing-Quan; Chen, De-You; Wen, Dan E-mail: deyouchen@126.com

    2013-11-01

    In the work [J. Y. Zhang and Z. Zhao, Massive particles's black hole tunneling and de Sitter tunneling, Nucl. Phys. B 725 (2005) 173.], the Hawking radiation of the massive particle via tunneling from the de Sitter cosmological horizon has been first described in the tunneling framework. However, the geodesic equation of the massive particle was unnaturally and awkwardly defined there by investigating the relation between the group and phase velocity. In this paper, we start from the Lagrangian analysis on the action to naturally produce the geodesic equation of the tunneling massive particle. Then, based on the new definition for the geodesic equation, we revisit the Hawking radiation of the massive particle via tunneling from the de Sitter cosmological horizon. It is noteworthy that, the highlight of our work is a new and important development of the Parikh-Wilczek's tunneling method, which can make it more physical.

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

    PubMed

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

    2015-03-01

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

  11. Magnetic Fields in Massive Filaments

    NASA Astrophysics Data System (ADS)

    Pillai, Thushara

    Magnetic fields pervade galaxies, shaping them from the largest scales to the smallest star forming scales. A firm understanding of their role is crucial to our understanding of the physics of ISM. A dominant phase of the ISM that has received considerable attention is that of filaments which are ubiquitous and dominate the mass reservoir in molecular clouds. Enormous progress has been made recently towards understanding filament properties. The next major step should be to understand the role of magnetic fields in filaments. We propose to take advantage of HAWC+ dust emission polarimeter now available on SOFIA to launch a pilot polarization study towards three major classes of filaments: (i) Pristine (ii) Hub-Filament systems and (iii) Perturbed. HAWC+ will trace the connection between the star forming cores and the filaments enveloping them. By covering a vast range in parameter space from quiescent to active filaments, we will be constraining the initial conditions prior to star formation, during star formation and after star formation (feedback from newly formed stars on their parent clouds.) The interpretation of observations will be supported by extensive custom-made numerical simulations of magnetized clouds and subsequent dust radiative transfer with various grain alignment mechanisms, as provided by collaborators. Combined, these observations will provide the first panoramic view of the magnetized nature of massive filaments in the ISM.

  12. Magnetic Fields in Massive Filaments

    NASA Astrophysics Data System (ADS)

    Pillai, G. S. Thushara

    2015-10-01

    Magnetic fields pervade galaxies, shaping them from the largest scales to the smallest star forming scales. A firm understanding of their role is crucial to our understanding of the physics of ISM. A dominant phase of the ISM that has received considerable attention is that of filaments which are ubiquitous and dominate the mass reservoir in molecular clouds. Enormous progress has been made recently towards understanding filament properties. The next major step should be to understand the role of magnetic fields in filaments. We propose to take advantage of HAWC+ dust emission polarimeter now available on SOFIA to launch a pilot polarization study towards three major classes of filaments: (i) Pristine (ii) Hub-Filament systems and (iii) Perturbed. HAWC+ will trace the connection between the star forming cores and the filaments enveloping them. By covering a vast range in parameter space from quiescent to active filaments, we will be constraining the initial conditions prior to star formation, during star formation and after star formation (feedback from newly formed stars on their parent clouds.) The interpretation of observations will be supported by extensive custom--made numerical simulations of magnetized clouds and subsequent dust radiative transfer with various grain alignment mechanisms, as provided by collaborators. Combined, these observations will provide the first panoramic view of the magnetized nature of massive filaments in the ISM.

  13. Inside-out formation of massive galaxies

    NASA Astrophysics Data System (ADS)

    de la Rosa, I. G.

    2017-03-01

    A significant fraction of the present day massive galaxies have compact cores embedded inside their disks or halos. Strikingly, those compact cores are similar to the massive high-redshift quiescent compact galaxies, nicknamed red-nuggets. We present observational evidence supporting an inside-out formation scenario, where present-day massive galaxies can begin as dense spheroidal cores (red-nuggets), around which either a spheroidal halo or a disk are accreted later. This contribution is based on the paper by de la Rosa et al. (2016).

  14. Fluid/gravity correspondence for massive gravity

    NASA Astrophysics Data System (ADS)

    Pan, Wen-Jian; Huang, Yong-Chang

    2016-11-01

    In this paper, we investigate the fluid/gravity correspondence in the framework of massive Einstein gravity. Treating the gravitational mass terms as an effective energy-momentum tensor and utilizing the Petrov-like boundary condition on a timelike hypersurface, we find that the perturbation effects of massive gravity in bulk can be completely governed by the incompressible Navier-Stokes equation living on the cutoff surface under the near horizon and nonrelativistic limits. Furthermore, we have concisely computed the ratio of dynamical viscosity to entropy density for two massive Einstein gravity theories, and found that they still saturate the Kovtun-Son-Starinets (KSS) bound.

  15. Venus - Volcano With Massive Landslides

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This Magellan full-resolution mosaic which covers an area 143 by 146 kilometers (89 by 91 miles) is centered at 55 degrees north latitude, 266 degrees east longitude. The bright feature, slightly south of center is interpreted to be a volcano, 15-20 kilometers (9.3 to 12.4 miles) in diameter with a large apron of blocky debris to its right and some smaller aprons to its left. A preferred explanation is that several massive catastrophic landslides dropped down steep slopes and were carried by their momentum out into the smooth, dark lava plains. At the base of the east-facing or largest scallop on the volcano is what appears to be a large block of coherent rock, 8 to 10 kilometers (5 to 6 miles) in length. The similar margin of both the scallop and block and the shape in general is typical of terrestrial slumped blocks (masses of rock which slide and rotate down a slope instead of breaking apart and tumbling). The bright lobe to the south of the volcano may either be a lava flow or finer debris from other landslides. This volcanic feature, characterized by its scalloped flanks is part of a class of volcanoes called scalloped or collapsed domes of which there are more than 80 on Venus. Based on the chute-like shapes of the scallops and the existence of a spectrum of intermediate to well defined examples, it is hypothesized that all of the scallops are remnants of landslides even though the landslide debris is often not visible. Possible explanations for the missing debris are that it may have been covered by lava flows, the debris may have weathered or that the radar may not be recognizing it because the individual blocks are too small

  16. Transthoracic Biopsy Causes Massive Subcutaneous Emphysema in a Low Risk Patient

    PubMed Central

    Dag, Yusuf

    2016-01-01

    Subcutaneous Emphysema (SE) can be defined as air leakage under skin from the respiratory or gastrointestinal system. It is frequently accompanied by pneumomediastinum. Thoracentesis, image-guided lung biopsies, pulmonary diseases and therapies resulting in necrosis can cause this pathology. The risk of pneumothorax and SE increased with the distance of the lesion to the pleura, and small size of the lesion. Although, our patient had low risk for SE, there were minimal pneumothoraces and massive SE. We consider that tumour necrosis and subcutaneous tissue may be related via transthoracic biopsy and this leads to massive SE. PMID:28050477

  17. Under-recognised paradox of neuropathy from rapid glycaemic control

    PubMed Central

    Leow, M; Wyckoff, J

    2005-01-01

    Insulin induced neuropathy has been reported previously in people with diabetes treated with insulin, and subsequently reported in patients with insulinomas. However, neuropathy caused by rapid glycaemic control in patients with poorly controlled diabetes with chronic hyperglycaemia is not a widely recognised entity among clinicians worldwide. It is expected that this phenomenon of paradoxical complication of neuropathy in the face of drastic decreases in glycosylated haemoglobin concentrations will assume greater importance with clinicians achieving glycaemic targets at a faster pace than before. PMID:15701742

  18. Paradoxical darkening and removal of pink tattoo ink.

    PubMed

    Kirby, William; Kaur, Ravneet Ruby; Desai, Alpesh

    2010-06-01

    It is widely accepted that Q-switched lasers are the gold-standard treatment for the resolution of unwanted tattoo ink. Although much safer than other tattoo removal modalities, the treatment of tattoo ink with Q-switched devices may be associated with long-term adverse effects including undesired pigmentary alterations such as tattoo ink darkening. Darkening of tattoo ink is most often reported in cosmetic, flesh-toned, white, peach, and pink tattoos. In this paper, we briefly review a case of pink tattoo ink that initially darkened paradoxically but eventually resolved with continued Q-switched laser treatments.

  19. The aneuploidy paradox: costs and benefits of an incorrect karyotype.

    PubMed

    Sheltzer, Jason M; Amon, Angelika

    2011-11-01

    Aneuploidy has a paradoxical effect on cell proliferation. In all normal cells analyzed to date, aneuploidy has been found to decrease the rate of cell proliferation. Yet, aneuploidy is also a hallmark of cancer, a disease of enhanced proliferative capacity, and aneuploid cells are frequently recovered following the experimental evolution of microorganisms. Thus, in certain contexts, aneuploidy might also have growth-advantageous properties. New models of aneuploidy and chromosomal instability have shed light on the diverse effects that karyotypic imbalances have on cellular phenotypes, and suggest novel ways of understanding the role of aneuploidy in development and disease.

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

    NASA Astrophysics Data System (ADS)

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

    2011-04-01

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

  1. Hormonal regulation of hair follicles exhibits a biological paradox.

    PubMed

    Randall, Valerie Anne

    2007-04-01

    Hair's importance for insulation and camouflage or human communication means that hairs need to change with season, age or sexual development. Regular, regenerating hair follicle growth cycles produce new hairs which may differ in colour and/or size, e.g., beard development. Hormones of the pineal-hypothalamus-pituitary axis coordinate seasonal changes, while androgens regulate most sexual aspects with paradoxically different effects depending on body site; compare beard growth and balding! Hormones affect follicular mesenchymal-epithelial interactions altering growing time, dermal papilla size and dermal papilla cell, keratinocyte and melanocyte activity. Greater understanding of these mechanisms should improve treatments for poorly controlled hair disorders, alopecia and hirsutism.

  2. [Paradoxical kinesis phenomenon in focal hand dystonia--writer's cramp].

    PubMed

    Shavlovskaia, O A; Orlova, O R; Golubev, V L

    2005-01-01

    Paradoxical kinesis (PK) phenomenon and its variants, exerting a beneficial influence on dystonia dynamics, are described using self clinical examination of 57 writer's cramp patients. PK was found in all the patients independently of writer's cramp variant, duration and severity. The most frequent writing maneuvers were as follows: hand printed (100%), proximal arm muscles writing (82.5%), individually selected writing instrument (67.5-80%), unusual means (67.5-75%), writing imitation with unlike-pen object (70%), marked papers (52.5%). The beneficial influence of PK phenomenon on dystonia expression may be considered as one of the directions of writer's cramp rehabilitation.

  3. [The paradoxical effect of persuasive communication in health education sessions].

    PubMed

    Piperini, Marie-Christine

    2012-01-01

    The purpose of this study was to examine the communication dynamics leading to the adoption of new attitudes and cognitions in health education sessions. We examined the verbal interactions at work in persuasive communication in 16 health education sessions. The study found that the medical expertise of the educator and the initial level of commitment of the participants had a positive effect on adherence to recommendations. However, persuasive communication in health education sessions appears to involve a paradoxical process in which criticism of the message can go hand in hand with the expression of an intention to implement new risk-reducing behaviors.

  4. SETI Before Marconi - Sunlight Beacons and the Fermi Paradox

    NASA Astrophysics Data System (ADS)

    Baxter, S.

    The strategies underlying the search for extraterrestrial intelligence are generally predicated on a model of civilisations with telecommunications technology searching for evidence of each other and making contact accordingly. It is argued that there is at least one plausible signalling type detectable to pre-radio civilisations: naked-eye `sunlight beacons'. A motive for attempting such communication could be the remote detection of the injection of greenhouse and other waste gases into a planetary atmosphere as a result of agricultural and early industrial activities. We may have been detectable, and contactable, since the Neolithic. An absence of such contacts is therefore a deepening of the Fermi Paradox.

  5. Mixing properties of growing networks and Simpson's paradox.

    PubMed

    Capocci, Andrea; Colaiori, Francesca

    2006-08-01

    The mixing properties of networks are usually inferred by comparing the degree of a node with the average degree of its neighbors. This kind of analysis often leads to incorrect conclusions: Assortative patterns may appear reversed by a mechanism known as Simpson's paradox. We prove this fact by analytical calculations and simulations on three classes of growing networks based on preferential attachment and fitness, where the disassortative behavior observed is a spurious effect. Our results give a crucial contribution to the debate about the origin of disassortative mixing, since networks previously classified as disassortative reveal instead assortative behavior to a careful analysis.

  6. Generalized absorber theory and the Einstein-Podolsky-Rosen paradox

    NASA Astrophysics Data System (ADS)

    Cramer, John G.

    1980-07-01

    A generalized form of Wheeler-Feynman absorber theory is used to explain the quantum-mechanical paradox proposed by Einstein, Podolsky, and Rosen (EPR). The advanced solutions of the electromagnetic wave equation and of relativistic quantum-mechanical wave equations are shown to play the role of "verifier" in quantum-mechanical "transactions," providing microscopic communication paths between detectors across spacelike intervals in violation of the EPR locality postulate. The principle of causality is discussed in the context of this approach, and possibilities for experimental tests of the theory are examined.

  7. Virtual black holes, remnants and the information paradox

    NASA Astrophysics Data System (ADS)

    Calmet, Xavier

    2015-02-01

    We revisit the question of the contributions of Planckian quantum black holes in general and of remnants in particular to low-energy physics observables. As long as quantum gravity preserves the symmetries of the low-energy effective field theory, we find that the bounds on the number of quantum black holes or remnants are very weak. Typically, we rule out using data on the anomalous magnetic moment of the muon that there are more than 1032 quantum black holes coupled to the standard model particles gravitationally. Remnants thus remain a viable option as a solution to the information paradox of black holes.

  8. Gravitational collapse, chaos in CFT correlators and the information paradox

    NASA Astrophysics Data System (ADS)

    Farahi, Arya; Pando Zayas, Leopoldo A.

    2014-06-01

    We consider gravitational collapse of a massless scalar field in asymptotically anti-de Sitter spacetime. Following the AdS/CFT dictionary we further study correlations in the field theory side by way of the Klein-Gordon equation of a probe scalar field in the collapsing background. We present evidence that in a certain regime the probe scalar field behaves chaotically, thus supporting Hawking's argument in the black hole information paradox proposing that although the information can be retrieved in principle, deterministic chaos impairs, in practice, the process of unitary extraction of information from a black hole. We emphasize that quantum chaos will change this picture. .

  9. Some considerations on molecular machines and Loschmidt paradox

    NASA Astrophysics Data System (ADS)

    Lucia, Umberto

    2015-03-01

    Molecular machines do not apparently satisfy the second law of thermodynamics. This holds to the Loschmidt paradox. Boltzmann introduced the irreversible evolution of any system towards a state of mechanical and thermal equilibrium. He expressed this result in his H-theorem. Loschmidt objected that the Boltzmann's result was inconsistent because it was obtained by using a time-symmetric dynamics, in contrast with the time asymmetry of the result. In this letter we show how these two problems can be related to the Gouy-Stodola theorem and to the interactions between open systems or open subsystems in the case of closed or isolated systems.

  10. Air Pollution

    MedlinePlus

    Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, ... Ozone, a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's ...

  11. A cosmological study in massive gravity theory

    SciTech Connect

    Pan, Supriya Chakraborty, Subenoy

    2015-09-15

    A detailed study of the various cosmological aspects in massive gravity theory has been presented in the present work. For the homogeneous and isotropic FLRW model, the deceleration parameter has been evaluated, and, it has been examined whether there is any transition from deceleration to acceleration in recent past, or not. With the proper choice of the free parameters, it has been shown that the massive gravity theory is equivalent to Einstein gravity with a modified Newtonian gravitational constant together with a negative cosmological constant. Also, in this context, it has been examined whether the emergent scenario is possible, or not, in massive gravity theory. Finally, we have done a cosmographic analysis in massive gravity theory.

  12. Evolution of Massive Stars at Low Metallicity

    NASA Astrophysics Data System (ADS)

    Meynet, Georges; Walborn, Nolan R.; Hunter, Ian; Martayan, Christophe; van Marle, Allard Jan; Marchenko, Sergey; Vink, Jorick S.; Limongi, Marco; Levesque, Emily M.; Modjaz, Maryam

    2008-06-01

    This paper reports the contributions made on the occasion of the Special Session entitled “Evolution of Massive Stars at Low Metallicity” which was held on Sunday, December 9, 2007 in Kauai (USA).

  13. Dwarf Galaxies with Active Massive Black Holes

    NASA Astrophysics Data System (ADS)

    Reines, Amy E.; Greene, J. E.; Geha, M. C.

    2014-01-01

    Supermassive black holes (BHs) live at the heart of essentially all massive galaxies with bulges, power AGN, and are thought to be important agents in the evolution of their hosts. However, the birth and growth of the first supermassive BH "seeds" is far from understood. While direct observations of these distant BHs in the infant Universe are unobtainable with current capabilities, massive BHs in present-day dwarf galaxies can place valuable constraints on the masses, formation path, and hosts of supermassive BH seeds. Using optical spectroscopy from the SDSS, we have systematically assembled the largest sample of dwarf galaxies hosting active massive BHs to date. These dwarf galaxies have stellar masses comparable to the Magellanic Clouds and contain some of the least-massive supermassive BHs known.

  14. Self-protection of massive cosmological gravitons

    SciTech Connect

    Berkhahn, Felix; Dietrich, Dennis D.; Hofmann, Stefan E-mail: dietrich@cp3.sdu.dk

    2010-11-01

    Relevant deformations of gravity present an exciting window of opportunity to probe the rigidity of gravity on cosmological scales. For a single-graviton theory, the leading relevant deformation constitutes a graviton mass term. In this paper, we investigate the classical and quantum stability of massive cosmological gravitons on generic Friedman backgrounds. For a Universe expanding towards a de Sitter epoch, we find that massive cosmological gravitons are self-protected against unitarity violations by a strong coupling phenomenon.

  15. Examining Taiwan's Paradox of Family Decline with a Household-Based Convoy

    ERIC Educational Resources Information Center

    Chen, Chaonan; Lin, Hui-Lin

    2008-01-01

    Taiwan's paradox of family decline is examined with a household-based convoy, which allows us to explore the paradox from two perspectives, namely, the modified extended family and the household-based convoy. The modified extended family refers to the reunion of spatially separated families covering two generations. The household-based convoy is…

  16. Continuous-variable Einstein-Podolsky-Rosen paradox with traveling-wave second-harmonic generation

    SciTech Connect

    Olsen, M.K.

    2004-09-01

    The Einstein-Podolsky-Rosen paradox and quantum entanglement are at the heart of quantum mechanics. Here we show that single-pass traveling-wave second-harmonic generation can be used to demonstrate both entanglement and the paradox with continuous variables that are analogous to the position and momentum of the original proposal.

  17. Can Virtue Be Taught and How? Confucius on the Paradox of Moral Education

    ERIC Educational Resources Information Center

    Huang, Yong

    2011-01-01

    In this paper I shall first examine an apparent paradox in Confucius' view on whether everyone is perfectible through education: on the one hand, he states that education should be provided to all, on the other hand, he says that common people cannot be made to know things. To understand this apparent paradox, I shall argue that education for…

  18. Facing Paradox Everyday: A Heideggerian Approach to the Ethics of Teaching

    ERIC Educational Resources Information Center

    d'Agnese, Vasco

    2016-01-01

    In this paper, I wish to offer insight into the role of paradox in teaching. I will do so by analyzing teachers' everyday work, taking a qualitative approach and constructing a small-scale empirical study. Philosophically, my attempt is framed by Heidegger's thought. Drawing from research data, I argue the following: (a) paradoxes and dilemmas are…

  19. [Effect of paradoxical sleep deprivation on elaboration and differentiation of alimentary conditioned reflexes].

    PubMed

    Koridze, M G; Nemsadze, N D

    1980-01-01

    Paradoxical sleep deprivation of cats by means of awakening them without any significant emotional stress does not affect the acquisition of sound discrimination. Paradoxical sleep deprivation by Jouvet's method producing emotional stress impairs the acquisition of sound discrimination. However, it fails to affect the reproduction of preliminary elaborated sound discrimination.

  20. Introducing the Levinthal's Protein Folding Paradox and Its Solution

    ERIC Educational Resources Information Center

    Martínez, Leandro

    2014-01-01

    The protein folding (Levinthal's) paradox states that it would not be possible in a physically meaningful time to a protein to reach the native (functional) conformation by a random search of the enormously large number of possible structures. This paradox has been solved: it was shown that small biases toward the native conformation result…

  1. The Use of Paradoxical Intention in the Treatment of Panic Attacks.

    ERIC Educational Resources Information Center

    Dattilio, Frank M.

    1987-01-01

    Discusses the counseling use of paradoxical intention, in which clients are told to perform responses that seem incompatible with the goal for which they are seeking help. The use of paradoxical intention in the treatment of panic attacks is described and a case example is included. The nature and implementation of the technique are discussed.…

  2. Three Abductive Solutions to the Meno Paradox--with Instinct, Inference, and Distributed Cognition

    ERIC Educational Resources Information Center

    Paavola, Sami; Hakkarainen, Kai

    2005-01-01

    This article analyzes three approaches to resolving the classical Meno paradox, or its variant, the learning paradox, emphasizing Charles S. Peirce's notion of abduction. Abduction provides a way of dissecting those processes where something new, or conceptually more complex than before, is discovered or learned. In its basic form, abduction is a…

  3. The Chinese Classroom Paradox: A Cross-Cultural Comparison of Teacher Controlling Behaviors

    ERIC Educational Resources Information Center

    Zhou, Ning; Lam, Shui-Fong; Chan, Kam Chi

    2012-01-01

    Chinese classrooms present an intriguing paradox to the claim of self-determination theory that autonomy facilitates learning. Chinese teachers appear to be controlling, but Chinese students do not have poor academic performance in international comparisons. The present study addressed this paradox by examining the cultural differences in…

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

    ERIC Educational Resources Information Center

    Yang, Tse-Chuan; Jensen, Leif; Haran, Murali

    2011-01-01

    The "rural paradox" refers to standardized mortality rates in rural areas that are unexpectedly low in view of well-known economic and infrastructural disadvantages there. We explore this paradox by incorporating social capital, a promising explanatory factor that has seldom been incorporated into residential mortality research. We do so while…

  5. Alma Observations of Massive Molecular Gas Filaments Encasing Radio Bubbles in the Phoenix Cluster

    NASA Astrophysics Data System (ADS)

    Russell, H. R.; McDonald, M.; McNamara, B. R.; Fabian, A. C.; Nulsen, P. E. J.; Bayliss, M. B.; Benson, B. A.; Brodwin, M.; Carlstrom, J. E.; Edge, A. C.; Hlavacek-Larrondo, J.; Marrone, D. P.; Reichardt, C. L.; Vieira, J. D.

    2017-02-01

    We report new ALMA observations of the CO(3-2) line emission from the 2.1+/- 0.3× {10}10 {M}ȯ molecular gas reservoir in the central galaxy of the Phoenix cluster. The cold molecular gas is fueling a vigorous starburst at a rate of 500{--}800 {M}ȯ {{yr}}-1 and powerful black hole activity in the forms of both intense quasar radiation and radio jets. The radio jets have inflated huge bubbles filled with relativistic plasma into the hot, X-ray atmospheres surrounding the host galaxy. The ALMA observations show that extended filaments of molecular gas, each 10{--}20 {kpc} long with a mass of several billion solar masses, are located along the peripheries of the radio bubbles. The smooth velocity gradients and narrow line widths along each filament reveal massive, ordered molecular gas flows around each bubble, which are inconsistent with gravitational free-fall. The molecular clouds have been lifted directly by the radio bubbles, or formed via thermal instabilities induced in low-entropy gas lifted in the updraft of the bubbles. These new data provide compelling evidence for close coupling between the radio bubbles and the cold gas, which is essential to explain the self-regulation of feedback. The very feedback mechanism that heats hot atmospheres and suppresses star formation may also paradoxically stimulate production of the cold gas required to sustain feedback in massive galaxies.

  6. Life history, immunity, Peto's paradox and tumours in birds.

    PubMed

    Møller, A P; Erritzøe, J; Soler, J J

    2017-03-02

    Cancer and tumours may evolve in response to life-history trade-offs between growth and duration of development on one hand, and between growth and maintenance of immune function on the other. Here, we tested whether (i) bird species with slow developmental rates for their body size experience low incidence of tumours because slow development allows for detection of rapid proliferation of cell lineages. We also test whether (ii) species with stronger immune response during development are more efficient at detecting tumour cells and hence suffer lower incidence of tumours. Finally, we tested Peto's paradox, that there is a positive relationship between tumour incidence and body mass. We used information on developmental rates and body mass from the literature and of tumour incidence (8468 birds) and size of the bursa of Fabricius for 7659 birds brought to a taxidermist in Denmark. We found evidence of the expected negative relationship between incidence of tumours and developmental rates and immunity after controlling for the positive association between tumour incidence and body size. These results suggest that evolution has modified the incidence of tumours in response to life history and that Peto's paradox may be explained by covariation between body mass, developmental rates and immunity.

  7. The Bangladesh paradox: exceptional health achievement despite economic poverty.

    PubMed

    Chowdhury, A Mushtaque R; Bhuiya, Abbas; Chowdhury, Mahbub Elahi; Rasheed, Sabrina; Hussain, Zakir; Chen, Lincoln C

    2013-11-23

    Bangladesh, the eighth most populous country in the world with about 153 million people, has recently been applauded as an exceptional health performer. In the first paper in this Series, we present evidence to show that Bangladesh has achieved substantial health advances, but the country's success cannot be captured simplistically because health in Bangladesh has the paradox of steep and sustained reductions in birth rate and mortality alongside continued burdens of morbidity. Exceptional performance might be attributed to a pluralistic health system that has many stakeholders pursuing women-centred, gender-equity-oriented, highly focused health programmes in family planning, immunisation, oral rehydration therapy, maternal and child health, tuberculosis, vitamin A supplementation, and other activities, through the work of widely deployed community health workers reaching all households. Government and non-governmental organisations have pioneered many innovations that have been scaled up nationally. However, these remarkable achievements in equity and coverage are counterbalanced by the persistence of child and maternal malnutrition and the low use of maternity-related services. The Bangladesh paradox shows the net outcome of successful direct health action in both positive and negative social determinants of health--ie, positives such as women's empowerment, widespread education, and mitigation of the effect of natural disasters; and negatives such as low gross domestic product, pervasive poverty, and the persistence of income inequality. Bangladesh offers lessons such as how gender equity can improve health outcomes, how health innovations can be scaled up, and how direct health interventions can partly overcome socioeconomic constraints.

  8. The immigrant paradox on internalizing symptoms among immigrant adolescents.

    PubMed

    Bowe, Anica G

    2017-02-01

    Understanding the immigrant paradox on health outcomes among UK's immigrant adolescents will greatly complement the research on immigrants that has already been established there by economists and interdisciplinary fields. This study used the first Longitudinal Study of Young People in England 2004-2010 database (N = 15,770) to determine a) whether there was evidence of the immigrant paradox on internalizing mental health symptoms between first generation (n = 753) and second plus generation (n = 3042) 14/15 year old immigrant adolescents in England and b) whether differences (if any) were moderated by ethnicity group membership (Black African, Black Caribbean, Indian, Pakistani, Bangladeshi, Asian Other, White Immigrant). Findings demonstrate that overall first generation adolescent immigrants had statistically fewer internalizing symptoms as compared to second plus generation, and that this was especially true for Black African adolescents. Effect sizes measures however indicated that these differences were negligible. Implications for protective factors and future studies are briefly discussed.

  9. Lekking without a paradox in the buff-breasted sandpiper

    USGS Publications Warehouse

    Lanctot, Richard B.; Scribner, Kim T.; Kempenaers, Bart; Weatherhead, Patrick J.

    1997-01-01

    Females in lek‐breeding species appear to copulate with a small subset of the available males. Such strong directional selection is predicted to decrease additive genetic variance in the preferred male traits, yet females continue to mate selectively, thus generating the lek paradox. In a study of buff‐breasted sandpipers (Tryngites subruficollis), we combine detailed behavioral observations with paternity analyses using single‐locus minisatellite DNA probes to provide the first evidence from a lek‐breeding species that the variance in male reproductive success is much lower than expected. In 17 and 30 broods sampled in two consecutive years, a minimum of 20 and 39 males, respectively, sired offspring. This low variance in male reproductive success resulted from effective use of alternative reproductive tactics by males, females mating with solitary males off leks, and multiple mating by females. Thus, the results of this study suggests that sexual selection through female choice is weak in buff‐breasted sandpipers. The behavior of other lek‐breeding birds is sufficiently similar to that of buff‐breasted sandpipers that paternity studies of those species should be conducted to determine whether leks generally are less paradoxical than they appear.

  10. Policy on synthetic biology: deliberation, probability, and the precautionary paradox.

    PubMed

    Wareham, Christopher; Nardini, Cecilia

    2015-02-01

    Synthetic biology is a cutting-edge area of research that holds the promise of unprecedented health benefits. However, in tandem with these large prospective benefits, synthetic biology projects entail a risk of catastrophic consequences whose severity may exceed that of most ordinary human undertakings. This is due to the peculiar nature of synthetic biology as a 'threshold technology' which opens doors to opportunities and applications that are essentially unpredictable. Fears about these potentially unstoppable consequences have led to declarations from civil society groups calling for the use of a precautionary principle to regulate the field. Moreover, the principle is prevalent in law and international agreements. Despite widespread political recognition of a need for caution, the precautionary principle has been extensively criticized as a guide for regulatory policy. We examine a central objection to the principle: that its application entails crippling inaction and incoherence, since whatever action one takes there is always a chance that some highly improbable cataclysm will occur. In response to this difficulty, which we call the 'precautionary paradox,' we outline a deliberative means for arriving at threshold of probability below which potential dangers can be disregarded. In addition, we describe a Bayesian mechanism with which to assign probabilities to harmful outcomes. We argue that these steps resolve the paradox. The rehabilitated PP can thus provide a viable policy option to confront the uncharted waters of synthetic biology research.

  11. [Once again about "Gregg paradox" and its solution].

    PubMed

    Mavrodiev, E V

    2002-01-01

    "Gregg paradox" means that monotypical groups containing the same species (or groups of species) will be equal each other although systematics considers them as different taxa. Thus if the order of placental mammalia Tubilidentata includes one species aardvark Orycteropus after, the order itself, its single family Orycteropodiaceae, single genus of the family Orycteropus and the single species Orycteropus after can be considered as equal to each other. To solve this disagreement the author asserts that taxa of any level can be regarded as an individual according to the taxa of higher rank. Possibility of such interpretation was already suggested by Georg Cantor (1985). He supposed that a set (class) can be regarded as unity by itself. In this case connections between taxa of different levels can be realized by Peano ratio of intrasitive conformities. In this model a genus will consist of species but not individuals, a type--of classes, etc. Thus, if a taxon x as an individual is an element of taxon y, and taxon y as an individual is an element of taxon z, then z according to x will be not only logical class, but class of classes and, hence we could not consider x as an element of z, because the latter consists of indecomposable individual-class y or some similar classes. In this situation "Gregg paradox" does not arise.

  12. Paradoxes of high and low velocities in modern geodynamics

    NASA Astrophysics Data System (ADS)

    Makarov, P. V.

    2016-11-01

    An analysis of the data on the vertical and horizontal movements of the Earth's crust obtained within recent 40 years has revealed paradoxical deviations of its deformations from the movements inherited from the past geological times. Currently, high local deformation velocities are observed both in the aseismic and seismically active regions. There are no clues to this phenomenon within the conventional concepts of geodynamics and mechanics of deformed solids. It is shown in this work that the paradoxes of high and low velocities could be solved if deformation processes taking place in the Earths' crust would be treated as the evolution of the stress-strain state of the loaded medium as a typical non-linear dynamic system. In this case, fracture develops in two stages—a comparatively slow quasi-stationary stage and a superfast catastrophic one, wherein the spatial localization of parameters is followed by the localization of the deformation process in time. This property is a fundamental characteristic of any non-linear dynamic systems.

  13. Pitch jnd and the tritone paradox: The linguistic nexus

    NASA Astrophysics Data System (ADS)

    Safari, Kourosh

    2002-11-01

    Previous research has shown a connection between absolute pitch (the ability to name a specific pitch in the absence of any reference) and native competence in a tone language (Deutsch, 1990). In tone languages, tone is one of the features which determines the lexical meaning of a word. This study investigates the relationship between native competence in a tone language and the just noticeable difference of pitch. Furthermore, the tritone paradox studies have shown that subjects hear two tritones (with bell-shaped spectral envelopes) as either ascending or descending depending on their linguistic backgrounds (Deutsch, 1987). It is hypothesized that the native speakers of tone languages have a higher JND for pitch, and hear the two tones of the tritone paradox as ascending, whereas, native speakers of nontone languages hear them as descending. This study will indicate the importance of early musical training for the development of acute tone sensitivity. It will also underline the importance of language and culture in the way it shapes our musical understanding. The significance of this study will be in the areas of music education and pedagogy.

  14. Paradoxical Herniation in the Postcraniectomy Syndrome: Report and Literature Update

    PubMed Central

    Ramos-Zúñiga, Rodrigo; Mares-Pais, Roberto; Gutiérrez-Avila, Oscar; Saldaña-Koppel, Daniel A.

    2016-01-01

    Introduction The decompressive craniectomy is a surgical strategy widely used with specific criteria to control the refractory intracranial pressure (ICP). However, it is important to warn about the presence of a postcraniectomy syndrome and analyze the risk-benefit on a long term. Case Report A 72-year-old male patient diagnosed with a subarachnoid hemorrhage secondary to the rupture of an anterior circulation aneurysm that develops vasospasm, secondary ischemia, and edema with signs of herniation that required a decompressive craniectomy on a first step. Afterwards, the aneurysm was approached and he consequently developed hydrocephaly. A ventriculoperitoneal shunt is installed, contralateral to the craniectomy, and progressive sinking of the skin flap, there is neurological deterioration and paradoxical herniation. Its association with the clinical deterioration by bronchoaspiration did not allow the cranioplasty to resolve the ICP decompensation. Conclusions The paradoxical herniation as part of the postcraniectomy syndrome is an increasingly common condition identified in adult patients with cortical atrophy, and who have also been treated with ventricular shunt systems. Timely cranioplasty represents the ideal therapeutic plan once the compromise from the mass effect has resolved to avoid complications derived from the decompressive craniectomy per se. PMID:26929899

  15. The Healthy Immigrant Paradox and Child Maltreatment: A Systematic Review.

    PubMed

    Millett, Lina S

    2016-10-01

    Prior studies suggest that foreign-born individuals have a health advantage, referred to as the Healthy Immigrant Paradox, when compared to native-born persons of the same socio-economic status. This systematic review examined whether the immigrant advantage found in health literature is mirrored by child maltreatment in general and its forms in particular. The author searched Academic Search Premier, CINAHL, CINAHL PLUS, Family and Society Studies Worldwide, MEDLINE, PsychINFO, Social Work Abstracts, and SocINdex for published literature through December 2015. The review followed an evidence-based Preferred Reporting Items for Systematic reviews and Meta-Analyses checklist. The author identified 822 unique articles, of which 19 met the inclusion criteria. The reviewed data showed strong support for the healthy immigrant paradox for a general form of maltreatment and physical abuse. The evidence for emotional and sexual abuse was also suggestive of immigrant advantage though relatively small sample size and lack of multivariate controls make these findings tentative. The evidence for neglect was mixed: immigrants were less likely to be reported to Child Protective Services; however, they had higher rates of physical neglect and lack of supervision in the community data. The study results warrant confirmation with newer data possessing strong external validity for immigrant samples.

  16. A resolution to the blue whiting (Micromesistius poutassou) population paradox?

    PubMed

    Pointin, Fabien; Payne, Mark R

    2014-01-01

    We provide the strongest evidence to date supporting the existence of two independent blue whiting (Micromesistius poutassou (Risso, 1827)) populations in the North Atlantic. In spite of extensive data collected in conjunction with the fishery, the population structure of blue whiting is poorly understood. On one hand, genetic, morphometric, otolith and drift modelling studies point towards the existence of two populations, but, on the other hand, observations of adult distributions point towards a single population. A paradox therefore arises in attempting to reconcile these two sets of information. Here we analyse 1100 observations of blue whiting larvae from the Continuous Plankton Recorder (CPR) from 1948-2005 using modern statistical techniques. We show a clear spatial separation between a northern spawning area, in the Rockall Trough, and a southern one, off the Porcupine Seabight. We further show a difference in the timing of spawning between these sites of at least a month, and meaningful differences in interannual variability. The results therefore support the two-population hypothesis. Furthermore, we resolve the paradox by showing that the acoustic observations cited in support of the single-population model are not capable of resolving both populations, as they occur too late in the year and do not extend sufficiently far south to cover the southern population: the confusion is the result of a simple observational artefact. We conclude that blue whiting in the North Atlantic comprises two populations.

  17. Patient autonomy in chronic care: solving a paradox

    PubMed Central

    Reach, Gérard

    2014-01-01

    The application of the principle of autonomy, which is considered a cornerstone of contemporary bioethics, is sometimes in obvious contradiction with the principle of beneficence. Indeed, it may happen in chronic care that the preferences of the health care provider (HCP), who is largely focused on the prevention of long term complications of diseases, differ from those, more present oriented, preferences of the patient. The aims of this narrative review are as follows: 1) to show that the exercise of autonomy by the patient is not always possible; 2) where the latter is not possible, to examine how, in the context of the autonomy principle, someone (a HCP) can decide what is good (a treatment) for someone else (a patient) without falling into paternalism. Actually this analysis leads to a paradox: not only is the principle of beneficence sometimes conflicting with the principle of autonomy, but physician’s beneficence may enter into conflict with the mere respect of the patient; and 3) to propose a solution to this paradox by revisiting the very concepts of the autonomous person, patient education, and trust in the patient–physician relationship: this article provides an ethical definition of patient education. PMID:24376345

  18. Patient autonomy in chronic care: solving a paradox.

    PubMed

    Reach, Gérard

    2013-12-12

    The application of the principle of autonomy, which is considered a cornerstone of contemporary bioethics, is sometimes in obvious contradiction with the principle of beneficence. Indeed, it may happen in chronic care that the preferences of the health care provider (HCP), who is largely focused on the prevention of long term complications of diseases, differ from those, more present oriented, preferences of the patient. The aims of this narrative review are as follows: 1) to show that the exercise of autonomy by the patient is not always possible; 2) where the latter is not possible, to examine how, in the context of the autonomy principle, someone (a HCP) can decide what is good (a treatment) for someone else (a patient) without falling into paternalism. Actually this analysis leads to a paradox: not only is the principle of beneficence sometimes conflicting with the principle of autonomy, but physician's beneficence may enter into conflict with the mere respect of the patient; and 3) to propose a solution to this paradox by revisiting the very concepts of the autonomous person, patient education, and trust in the patient-physician relationship: this article provides an ethical definition of patient education.

  19. Extending the core paradox posed by an early dynamo

    NASA Astrophysics Data System (ADS)

    Tarduno, J. A.; Cottrell, R. D.

    2014-12-01

    New, higher values of core thermal conductivity, together with the reliance of any early geodynamo on thermal convection, represent a paradox (Olson, 2013). These factors suggest either early Earth lacked an internally-generated magnetic field or novel mechanisms for driving an early dynamo. The oldest record of past field strength from in situ igneous rocks comes from 3.4 to 3.45 Ga dacites of the Barberton and Nondweni Greenstone belts of South Africa. These analyses, based on single silicate crystals containing magnetic inclusions with ideal recording characteristics, indicate a field strength within 50 to 70% of the present-day field (Tarduno et al., 2010). Much older igneous rocks are generally not viable as paleomagnetic recorders because of their high metamorphic state (amphibolite grade or higher). Here we discuss extending Earth's magnetic field history further back in time using Archean and Hadean zircons hosting magnetic inclusions that are now found in younger sedimentary units of low metamorphic grade. Thellier-Coe paleointensity data passing reliability checks from zircons of the Jack Hills belt (Western Australia) suggest the presence of a magnetic field at 3.55 Ga, thereby extending the core paradox by 100 million years. We will discuss our continuing efforts to test for the presence/absence of a dynamo field between 3.55 Ga and 4.2 Ga.

  20. Paradoxical Reactions and the Immune Reconstitution Inflammatory Syndrome.

    PubMed

    Church, L W Preston; Chopra, Amit; Judson, Marc A

    2017-03-01

    In HIV-infected individuals, paradoxical reactions after the initiation of antiretroviral therapy (ART) are associated with a variety of underlying infections and have been called the immune reconstitution inflammatory syndrome (IRIS). In cases of IRIS associated with tuberculosis (TB), two distinct patterns of disease are recognized: (i) the progression of subclinical TB to clinical disease after the initiation of ART, referred to as unmasking, and (ii) the progression or appearance of new clinical and/or radiographic disease in patients with previously recognized TB after the initiation of ART, the classic or "paradoxical" TB-IRIS. IRIS can potentially occur in all granulomatous diseases, not just infectious ones. All granulomatous diseases are thought to result from interplay of inflammatory cells and mediators. One of the inflammatory cells thought to be integral to the development of the granuloma is the CD4 T lymphocyte. Therefore, HIV-infected patients with noninfectious granulomatous diseases such as sarcoidosis may also develop IRIS reactions. Here, we describe IRIS in HIV-infected patients with TB and sarcoidosis and review the basic clinical and immunological aspects of these phenomena.

  1. Patent foramen ovale and paradoxical systemic embolism: a bibliographic review

    NASA Technical Reports Server (NTRS)

    Foster, Philip P.; Boriek, Aladin M.; Butler, Bruce D.; Gernhardt, Michael L.; Bove, Alfred A.

    2003-01-01

    A patent foramen ovale (PFO) has been reported to be an important risk factor for cardioembolic cerebrovascular accidents through paradoxical systemic embolization, and it provides one potential mechanism for the paradoxical systemic embolization of venous gas bubbles produced after altitude or hyperbaric decompressions. Here, we present in a single document a summary of the original findings and views from authors in this field. It is a comprehensive review of 145 peer-reviewed journal articles related to PFO that is intended to encourage reflection on PFO detection methods and on the possible association between PFO and stroke. There is a heightened debate on whether aviators, astronauts, and scuba divers should go through screening for PFO. Because it is a source of an important controversy, we prefer to present the findings in the format of a neutral bibliographic review independent of our own opinions. Each cited peer-reviewed article includes a short summary in which we attempt to present potential parallels with the pathophysiology of decompression bubbles. Two types of articles are summarized, as follows. First, we report the original clinical and physiological findings which focus on PFO. The consistent reporting sequence begins by describing the method of detection of PFO and goal of the study, followed by bulleted results, and finally the discussion and conclusion. Second, we summarize from review papers the issues related only to PFO. At the end of each section, an abstract with concluding remarks based on the cited articles provides guidelines.

  2. Black hole remnants and the information loss paradox

    NASA Astrophysics Data System (ADS)

    Chen, P.; Ong, Y. C.; Yeom, D.-h.

    2015-11-01

    Forty years after the discovery of Hawking radiation, its exact nature remains elusive. If Hawking radiation does not carry any information out from the ever shrinking black hole, it seems that unitarity is violated once the black hole completely evaporates. On the other hand, attempts to recover information via quantum entanglement lead to the firewall controversy. Amid the confusions, the possibility that black hole evaporation stops with a "remnant" has remained unpopular and is often dismissed due to some "undesired properties" of such an object. Nevertheless, as in any scientific debate, the pros and cons of any proposal must be carefully scrutinized. We fill in the void of the literature by providing a timely review of various types of black hole remnants, and provide some new thoughts regarding the challenges that black hole remnants face in the context of the information loss paradox and its latest incarnation, namely the firewall controversy. The importance of understanding the role of curvature singularity is also emphasized, after all there remains a possibility that the singularity cannot be cured even by quantum gravity. In this context a black hole remnant conveniently serves as a cosmic censor. We conclude that a remnant remains a possible end state of Hawking evaporation, and if it contains large interior geometry, may help to ameliorate the information loss paradox and the firewall controversy. We hope that this will raise some interests in the community to investigate remnants more critically but also more thoroughly.

  3. Unveiling consumer’s privacy paradox behaviour in an economic exchange

    PubMed Central

    Li, Xiao-Bai

    2015-01-01

    Privacy paradox is of great interest to IS researchers and firms gathering personal information. It has been studied from social, behavioural, and economic perspectives independently. However, prior research has not examined the degrees of influence these perspectives contribute to the privacy paradox problem. We combine both economic and behavioural perspectives in our study of the privacy paradox with a price valuation of personal information through an economic experiment combined with a behavioural study on privacy paradox. Our goal is to reveal more insights on the privacy paradox through economic valuation on personal information. Results indicate that general privacy concerns or individual disclosure concerns do not have a significant influence on the price valuation of personal information. Instead, prior disclosure behaviour in specific scenario, like with healthcare providers or social networks, is a better indicator of consumer price valuations. PMID:27708687

  4. The Information Age and Hot Air.

    PubMed

    Austin, Paul N

    2015-08-01

    Forced-air warmers have been used for over twenty years to help prevent and treat inadvertent perioperative hypothermia. One result of hypothermia can be an increased risk of surgical site infection. Paradoxically, the question has been raised about the role of forced-air warmers in causing surgical site infections. A manufacturer of a competing device has been sending information directly to clinicians with warnings about using forced-air warmers with patients undergoing total joint arthroplasty. Three reviews have been published and none of these condemned the use of forced-air warmers in the operating room including with patients undergoing total joint arthroplasty. Clinicians must continue to seek information about this problem from peer-reviewed journals and not rely on interpretation by others such as manufacturers.

  5. The Paradox and Fog of Supervision: Site for the Encounters and Growth of Praxis, Persons and Voices

    ERIC Educational Resources Information Center

    Cherry, Nita

    2012-01-01

    Purpose: Several paradoxes have been presented in the literature as inherent in supervision of doctoral students. The purpose of this paper is to explore these paradoxes and offer the concept of praxis as a way of effectively engaging with complex and paradoxical dimensions of supervision, rather than denying or avoiding them.…

  6. Massive Cerebrospinal Fluid Leak of the Temporal Bone

    PubMed Central

    Manno, Alessandra; Pasqualitto, Emanuela; Ciofalo, Andrea; Angeletti, Diletta; Pasquariello, Benedetta

    2016-01-01

    Cerebrospinal fluid (CSF) leakage of the temporal bone region is defined as abnormal communications between the subarachnoidal space and the air-containing spaces of the temporal bone. CSF leak remains one of the most frequent complications after VS surgery. Radiotherapy is considered a predisposing factor for development of temporal bone CSF leak because it may impair dural repair mechanisms, thus causing inadequate dural sealing. The authors describe the case of a 47-year-old man with a massive effusion of CSF which extended from the posterior and lateral skull base to the first cervical vertebrae; this complication appeared after a partial enucleation of a vestibular schwannoma (VS) with subsequent radiation treatment and second operation with total VS resection. PMID:27597915

  7. Massive Cerebrospinal Fluid Leak of the Temporal Bone.

    PubMed

    Iannella, Giannicola; Manno, Alessandra; Pasqualitto, Emanuela; Ciofalo, Andrea; Angeletti, Diletta; Pasquariello, Benedetta; Magliulo, Giuseppe

    2016-01-01

    Cerebrospinal fluid (CSF) leakage of the temporal bone region is defined as abnormal communications between the subarachnoidal space and the air-containing spaces of the temporal bone. CSF leak remains one of the most frequent complications after VS surgery. Radiotherapy is considered a predisposing factor for development of temporal bone CSF leak because it may impair dural repair mechanisms, thus causing inadequate dural sealing. The authors describe the case of a 47-year-old man with a massive effusion of CSF which extended from the posterior and lateral skull base to the first cervical vertebrae; this complication appeared after a partial enucleation of a vestibular schwannoma (VS) with subsequent radiation treatment and second operation with total VS resection.

  8. Heavy element abundances and massive star formation

    NASA Technical Reports Server (NTRS)

    Wang, Boqi; Silk, Joseph

    1993-01-01

    The determination of the stellar initial mass function (IMF) remains a great challenge in astronomy. In the solar neighborhood, the IMF is reasonable well determined for stellar masses from about 0.1 to 60 solar mass. However, outside the solar neighborhood, the IMF is poorly known. Among those frequently discussed arguments favoring a different IMF outside the solar neighborhood are the estimated time to consume the remaining gas in spiral galaxies, and the high rate of forming massive stars in starburst galaxies. An interesting question then is whether there may be an independent way of testing possible variations in the IMF. Indeed, the heavy elements in the interstellar medium are mostly synthesized in massive stars, so increasing, or decreasing, the fraction of massive stars naturally leads to a variation in the heavy element yield, and thus, the metallicity. The observed abundance should severely constrain any deviations of the IMF from the locally determined IMF. We focus on element oxygen, which is the most abundant heavy element in the interstellar medium. Oxygen is ejected only by massive stars that can become Type 1 supernovae, and the oxygen abundance is, therefore, a sensitive function of the fraction of massive stars in the IMF. Adopting oxygen enables us to avoid uncertainties in Type 1 supernovae. We use the nucleosynthesis results to calculate the oxygen yield for given IMF. We then calculate the oxygen abundance in the interstellar medium assuming instantaneous recycling of oxygen.

  9. A Hunt for Massive Starless Cores

    NASA Astrophysics Data System (ADS)

    Kong, Shuo; Tan, Jonathan C.; Caselli, Paola; Fontani, Francesco; Liu, Mengyao; Butler, Michael J.

    2017-01-01

    We carry out an ALMA {{{N}}}2{{{D}}}+(3-2) and 1.3 mm continuum survey of 32 high-mass surface density regions of seven infrared dark clouds, with the aim of finding massive starless cores that may form the initial conditions for the formation of massive stars. Cores showing strong {{{N}}}2{{{D}}}+(3-2) emission are expected to be highly deuterated and indicative of early, potentially pre-stellar stages of star formation. We also present maps of these regions in ancillary line tracers, including C18O(2-1), DCN(3-2), and DCO+(3-2). Over 100 {{{N}}}2{{{D}}}+ cores are identified with our newly developed core-finding algorithm, based on connected structures in position–velocity space. The most massive core has ∼ 70 {M}ȯ (potentially ∼ 170 {M}ȯ ) and so may be representative of the initial conditions or early stages of massive star formation. The existence and dynamical properties of such cores constrain massive star formation theories. We measure the line widths and thus velocity dispersion of six of the cores with strongest {{{N}}}2{{{D}}}+(3-2) line emission, finding results that are generally consistent with virial equilibrium of pressure confined cores.

  10. Acute management of vascular air embolism.

    PubMed

    Shaikh, Nissar; Ummunisa, Firdous

    2009-09-01

    Vascular air embolism (VAE) is known since early nineteenth century. It is the entrainment of air or gas from operative field or other communications into the venous or arterial vasculature. Exact incidence of VAE is difficult to estimate. High risk surgeries for VAE are sitting position and posterior fossa neurosurgeries, cesarean section, laparoscopic, orthopedic, surgeries invasive procedures, pulmonary overpressure syndrome, and decompression syndrome. Risk factors for VAE are operative site 5 cm above the heart, creation of pressure gradient which will facilitate entry of air into the circulation, orogenital sex during pregnancy, rapid ascent in scuba (self contained underwater breathing apparatus) divers and barotrauma or chest trauma. Large bolus of air can lead to right ventricular air lock and immediate fatality. In up to 35% patient, the foramen ovale is patent which can cause paradoxical arterial air embolism. VAE affects cardiovascular, pulmonary and central nervous system. High index of clinical suspicion is must to diagnose VAE. The transesophgeal echocardiography is the most sensitive device which will detect smallest amount of air in the circulation. Treatment of VAE is to prevent further entrainment of air, reduce the volume of air entrained and haemodynamic support. Mortality of VAE ranges from 48 to 80%. VAE can be prevented significantly by proper positioning during surgery, optimal hydration, avoiding use of nitrous oxide, meticulous care during insertion, removal of central venous catheter, proper guidance, and training of scuba divers.

  11. Primordial inhomogeneities from massive defects during inflation

    NASA Astrophysics Data System (ADS)

    Firouzjahi, Hassan; Karami, Asieh; Rostami, Tahereh

    2016-10-01

    We consider the imprints of local massive defects, such as a black hole or a massive monopole, during inflation. The massive defect breaks the background homogeneity. We consider the limit that the physical Schwarzschild radius of the defect is much smaller than the inflationary Hubble radius so a perturbative analysis is allowed. The inhomogeneities induced in scalar and gravitational wave power spectrum are calculated. We obtain the amplitudes of dipole, quadrupole and octupole anisotropies in curvature perturbation power spectrum and identify the relative configuration of the defect to CMB sphere in which large observable dipole asymmetry can be generated. We observe a curious reflection symmetry in which the configuration where the defect is inside the CMB comoving sphere has the same inhomogeneous variance as its mirror configuration where the defect is outside the CMB sphere.

  12. Pseudoangiomatous stromal hyperplasia causing massive breast enlargement.

    PubMed

    Bourke, Anita Geraldine; Tiang, Stephen; Harvey, Nathan; McClure, Robert

    2015-10-16

    Pseudoangiomatous stromal hyperplasia (PASH) of the breast is a benign mesenchymal proliferative process, initially described by Vuitch et al. We report an unusual case of a 46-year-old woman who presented with a 6-week history of bilateral massive, asymmetrical, painful enlargement of her breasts, without a history of trauma. On clinical examination, both breasts were markedly enlarged and oedematous, but there were no discrete palpable masses. Preoperative image-guided core biopsies and surgery showed PASH. PASH is increasingly recognised as an incidental finding on image-guided core biopsy performed for screen detected lesions. There are a few reported cases of PASH presenting as rapid breast enlargement. In our case, the patient presented with painful, asymmetrical, massive breast enlargement. Awareness needs to be raised of this entity as a differential diagnosis in massive, painful breast enlargement.

  13. HST Infrared Imaging of MASSIVE Survey Galaxies

    NASA Astrophysics Data System (ADS)

    Jensen, Joseph B.; Goullaud, Charles; Blakeslee, John; Mitchiner, Casey; Ma, Chung-Pei; Greene, Jenny E.; McConnell, Nicholas J.; Thomas, Jens

    2017-01-01

    We have recently obtained high-resolution HST WFC3/IR F110W (J-band) images of 34 early-type galaxies in the MASSIVE study sample. These galaxies are among the most massive in the local universe, and were chosen to study the connection between supermassive central black holes and their host galaxies. To determine accurate masses for the black holes, we are measuring high-precision surface brightness fluctuation (SBF) distances to the galaxies. The WFC3/IR data also allow us to measure high spatial resolution central surface brightness profiles to understand better the nuclear structure and dynamics of the galaxies. We present a first look at the IR images, profiles, and SBF magnitudes for 34 galaxies in the MASSIVE sample.

  14. Gyromagnetic ratio of a massive body.

    NASA Technical Reports Server (NTRS)

    Cohen, J. M.; Tiomno, J.; Wald, R. M.

    1973-01-01

    It is well known that the gyromagnetic ratio (g factor) of a classical, slowly rotating body whose charge density is proportional to its mass density must be equal to unity. However, if the body is very massive, the spacetime curvature effects of general relativity become important and the result g = 1 is no longer valid. We calculate here the gyromagnetic ratio of a slowly rotating, massive shell with uniform charge density. When the shell is large compared with the Schwarzschild radius we have g = 1, but as the shell becomes more massive the g factor increases. In the limit as the shell approaches its Schwarzschild radius we obtain g approaching 2 (the same value as for an electron).

  15. Massive Particle Reflection from Moving Mirrors

    NASA Astrophysics Data System (ADS)

    Sfarti, Adrian

    2016-09-01

    We investigate the reflection of massive particles from moving mirrors. The adoption of the formalism based on the energy-momentum allowed us to derive the most general set of formulas, valid for massive and, in the limit, also for massless particles. We show that the momentum change of the reflecting particle always lies along the normal to the mirror, independent of the mirror speed. The subject is interesting not only to physicists designing concentrators for fascicles of massive particles and electron microscopes but also to computer scientists working in raytracing operating in the photon sector. The paper, far from being only theoretical, has profound and novel practical applications in both domains of engineering design and computer science.

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

    PubMed Central

    Momeni, Naghmeh; Rabbat, Michael

    2016-01-01

    The friendship paradox is the phenomenon that in social networks, people on average have fewer friends than their friends do. The generalized friendship paradox is an extension to attributes other than the number of friends. The friendship paradox and its generalized version have gathered recent attention due to the information they provide about network structure and local inequalities. In this paper, we propose several measures of nodal qualities which capture different aspects of their activities and influence in online social networks. Using these measures we analyse the prevalence of the generalized friendship paradox over Twitter and we report high levels of prevalence (up to over 90% of nodes). We contend that this prevalence of the friendship paradox and its generalized version arise because of the hierarchical nature of the connections in the network. This hierarchy is nested as opposed to being star-like. We conclude that these paradoxes are collective phenomena not created merely by a minority of well-connected or high-attribute nodes. Moreover, our results show that a large fraction of individuals can experience the generalized friendship paradox even in the absence of a significant correlation between degrees and attributes. PMID:26863225

  17. The paradox of palliative care nursing across cultural boundaries.

    PubMed

    Somerville, Jacqueline

    2007-12-01

    The purpose of this qualitative study, using a modified grounded theory approach, was to investigate how palliative care nurses care for people from cultural backgrounds other than their own. Ten palliative care nurses were interviewed. The semi-structured interviews were tape-recorded and transcribed verbatim. Analysis commenced as soon as data began to emerge. The findings show that palliative nursing across cultural boundaries is paradoxical. In endeavouring to treat everyone equally, nurses treated everyone as individuals. They made intense efforts to transcend both cultural and language barriers. The nurses gave of themselves when caring for the patients, but their endeavours were impeded by limited resources and a lack of education. The theory of cross-cultural endeavour in palliative nursing was developed to explain how palliative care nurses care for patients from cultures other than their own.

  18. BMP signaling and its paradoxical effects in tumorigenesis and dissemination

    PubMed Central

    Zhang, Lijie; Ye, Yingnan; Long, Xinxin; Xiao, Pei; Ren, Xiubao; Yu, Jinpu

    2016-01-01

    Bone morphogenetic proteins (BMPs) play important roles in embryonic and postnatal development by regulating cell differentiation, proliferation, motility, and survival, thus maintaining homeostasis during organ and tissue development. BMPs can lead to tumorigenesis and regulate cancer progression in different stages. Therefore, we summarized studies on BMP expression, the clinical significance of BMP dysfunction in various cancer types, and the molecular regulation of various BMP-related signaling pathways. We emphasized on the paradoxical effects of BMPs on various aspects of carcinogenesis, including epithelial–mesenchymal transition (EMT), cancer stem cells (CSCs), and angiogenesis. We also reviewed the molecular mechanisms by which BMPs regulate tumor generation and progression as well as potential therapeutic targets against BMPs that might be valuable in preventing tumor growth and invasion. PMID:27661009

  19. Magnetobiology: the kT paradox and possible solutions.

    PubMed

    Binhi, V N; Rubin, A B

    2007-01-01

    The article discusses the so-called 'kT problem' with its formulation, content, and consequences. The usual formulation of the problem points out the paradox of biological effects of weak low-frequency magnetic fields. At the same time, the formulation is based on several implicit assumptions. Analysis of these assumptions shows that they are not always justified. In particular, molecular targets of magnetic fields in biological tissues may operate under physical conditions that do not correspond to the aforementioned assumptions. Consequently, as it is, the kT problem may not be an argument against the existence of non thermal magnetobiological effects. Specific examples are discussed: magnetic nanoparticles found in many organisms, long-lived rotational states of some molecules within protein structures, spin magnetic moments in radical pairs, and magnetic moments of protons in liquid water.

  20. Paradoxical form of filled/empty optical illusion.

    PubMed

    Wackermann, Jiri; Kastner, Kristina

    2009-01-01

    The filled/empty illusion (Oppel-Kundt) is one of the oldest geometrical-optical illusions, but the determinants of the illusion are not yet sufficiently understood. We studied magnitude of the illusory effect as a function of the height of vertical strokes subdividing a spatial extension of fixed length, using the psychophysical standard-variable matching paradigm. For vertical strokes shorter than, or of the same height as strokes delimiting the standard, the length was over-reproduced consistently with earlier studies of the illusion. However, for vertical strokes three times longer than the delimiters, the illusory effect paradoxically decreased, and attained negative values in two of six subjects. The magnitude of the effect thus depends on the patterning of the space between the delimiters, not merely on the number of subdividing elements.

  1. DTC genetic testing: pendulum swings and policy paradoxes.

    PubMed

    Caulfield, T

    2012-01-01

    After decades of optimistic portrayals, there has been a shift in the way that the popular press represents genomic research. A skeptical view has become more common. The central reason for this pendulum swing away from popular support is the harsh truth that most genetic risk information just isn't that predictive. This reality has created a fascinating policy paradox. If, as many in the scientific community are now saying, genetic information is not the oracle of our future health as we were once led to believe, and if access does not, for most, cause harm, why regulate the area? Why worry about shoddy direct-to-consumer (DTC) genetic testing companies? One primary justification, and one endorsed by the recent Canadian College of Medical Geneticists (CCMG) Policy Statement on DTC Genetics Testing, is that information that is conveyed to the public about genetics via marketing and to those who access DTC tests should, at a minimum, be accurate.

  2. Braess's paradox in oscillator networks, desynchronization and power outage

    NASA Astrophysics Data System (ADS)

    Witthaut, Dirk; Timme, Marc

    2012-08-01

    Robust synchronization is essential to ensure the stable operation of many complex networked systems such as electric power grids. Increasing energy demands and more strongly distributing power sources raise the question of where to add new connection lines to the already existing grid. Here we study how the addition of individual links impacts the emergence of synchrony in oscillator networks that model power grids on coarse scales. We reveal that adding new links may not only promote but also destroy synchrony and link this counter-intuitive phenomenon to Braess's paradox known for traffic networks. We analytically uncover its underlying mechanism in an elementary grid example, trace its origin to geometric frustration in phase oscillators, and show that it generically occurs across a wide range of systems. As an important consequence, upgrading the grid requires particular care when adding new connections because some may destabilize the synchronization of the grid—and thus induce power outages.

  3. K2P Potassium Channels, Mysterious and Paradoxically Exciting

    PubMed Central

    Goldstein, Steve A. N.

    2013-01-01

    New evidence reveals that the common electrolyte disorder hypokalemia can induce K2P1 channels that are normally selective for K+ to break the rules and conduct Na+. This defiant behavior leads to paradoxical depolarization of many cells in the heart, increasing the risk for lethal arrhythmia. The new research resolves a mystery uncovered 50 years ago and bestows an array of new riddles. Here, I discuss how K2P1 might achieve this alchemy—through stable residence of the K+ selectivity filter in a Na+-conductive state between its open and C-inactive configurations—and predict that other K+ channels and environmental stimuli will be discovered to produce the same excitatory misconduct. PMID:21868351

  4. A computational approach to the twin paradox in curved spacetime

    NASA Astrophysics Data System (ADS)

    Fung, Kenneth K. H.; Clark, Hamish A.; Lewis, Geraint F.; Wu, Xiaofeng

    2016-09-01

    Despite being a major component in the teaching of special relativity, the twin ‘paradox’ is generally not examined in courses on general relativity. Due to the complexity of analytical solutions to the problem, the paradox is often neglected entirely, and students are left with an incomplete understanding of the relativistic behaviour of time. This article outlines a project, undertaken by undergraduate physics students at the University of Sydney, in which a novel computational method was derived in order to predict the time experienced by a twin following a number of paths between two given spacetime coordinates. By utilising this method, it is possible to make clear to students that following a geodesic in curved spacetime does not always result in the greatest experienced proper time.

  5. Too similar, too different: the paradoxical dualism of psychiatric stigma.

    PubMed

    Gergel, Tania Louise

    2014-08-01

    Challenges to psychiatric stigma fall between a rock and a hard place. Decreasing one prejudice may inadvertently increase another. Emphasising similarities between mental illness and 'ordinary' experience to escape the fear-related prejudices associated with the imagined 'otherness' of persons with mental illness risks conclusions that mental illness indicates moral weakness and the loss of any benefits of a medical model. An emphasis on illness and difference from normal experience risks a response of fear of the alien. Thus, a 'likeness-based' and 'unlikeness-based' conception of psychiatric stigma can lead to prejudices stemming from paradoxically opposing assumptions about mental illness. This may create a troubling impasse for anti-stigma campaigns.

  6. Acquired Fontan paradox in isolated right ventricular cardiomyopathy

    PubMed Central

    Saran, Mahim; Sivasubramonian, Sivasankaran; Abhilash, Sreevilasam P; Tharakan, Jaganmohan A

    2016-01-01

    A 44-year-old woman presented with features of congestive heart failure. Echocardiography revealed severe right ventricular dysfunction along with passive minimally pulsatile pulmonary blood flow suggesting very high systemic venous pressures. This was confirmed with cardiac catheterization in which the pressures of superior vena cava and inferior vena cava (19 mmHg) were higher than the pulmonary artery pressures (17 mmHg). Elevation of systemic venous pressures above the pulmonary venous pressures, Fontan paradox, to drive the forward flow, is a specific feature of artificially created cavopulmonary shunts. Late stage of isolated right ventricular cardiomyopathy resulted in the spontaneous evolution of Fontan circulation with a nonfunctional right ventricle in this patient. PMID:27625525

  7. [Paradoxical transtentorial herniation, extreme trephined syndrome sign: A case report].

    PubMed

    Narro-Donate, Jose Maria; Huete-Allut, Antonio; Escribano-Mesa, Jose A; Rodríguez-Martínez, Virginia; Contreras-Jiménez, Ascensión; Masegosa-González, Jose

    2015-01-01

    The current increasing use of decompressive craniectomy carries the implicit appearance of complications due to alterations in both intracranial pressure and in the hydrostatic-hemodynamic equilibrium. Paradoxical transtentorial herniation represents a rare manifestation, included in "trephine syndrome", extremely critical but with relatively simple treatment. We present the case of a 56-year-old woman with no interesting medical history, who, after an olfactory groove meningioma surgery, presented a haemorrhage located in the surgical area with an important oedema. The patient required a second emergency surgery without any chance of conserving the cranial vault. During the post-operational period, great neurological deterioration in orthostatic position was noticed, which resolved spontaneously in decubitus. This deficit was resolved with bone replacement afterwards. We discuss possible predisposing factors and aetiologies of this pathology.

  8. The Gibbs paradox and the distinguishability of identical particles

    NASA Astrophysics Data System (ADS)

    Versteegh, Marijn A. M.; Dieks, Dennis

    2011-07-01

    Identical classical particles are distinguishable. This distinguishability affects the number of ways W a macrostate can be realized on the microlevel, and from the relation S =k ln W leads to a nonextensive expression for the entropy. This result is usually considered incorrect because of its inconsistency with thermodynamics. It is sometimes concluded from this inconsistency that identical particles are fundamentally indistinguishable and that quantum mechanics is indispensable for making sense of this inconsistency. In contrast, we argue that the classical statistics of distinguishable particles and the resulting nonextensive entropy function are perfectly acceptable from both a theoretical and an experimental perspective. The inconsistency with thermodynamics can be removed by taking into account that the entropy concept in statistical mechanics is not completely identical to the thermodynamical one. We observe that even identical quantum particles are in some cases distinguishable, and conclude that quantum mechanics is irrelevant to the Gibbs paradox.

  9. Coping with paradoxes of risk communication: Observations and suggestions

    SciTech Connect

    Johnson, B.B. )

    1993-06-01

    The maturation of the field of risk communication has resulted in several manuals, a National Research Council review, a Society for Risk Analysis subgroup, and critics. Critics Pieter-Jan Stalen and Rob Coppock, and Harry Otway and Brian Wynne, have pointed out that much risk communication is impractical or paradoxical. In this letter, the author supports many of the criticisms of these critics, but also discusses errors and omissions in their viewpoints that he feels will inhibit progress in effective risk communication. Topics discussed are motivations for risk communication, the practicality of advice, the audience for risk communication, credibility, and whose interests are best served by risk communication. The purpose of this essay is therefore to spur further debate on the issue of risk communication. 13 refs.

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

    PubMed

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

    2016-04-01

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

  11. Disability, inclusion and the Christian Church: practice, paradox or promise.

    PubMed

    Clapton, J

    1997-10-01

    In Western society, Christian Churches historically have been, and contemporarily are, involved with people perceived with disability. While they may practise biblical ethical imperatives such as care, compassion, mercy, support, welfare and charity, Churches have, paradoxically, only minimally offered cohesive or explicit moral notions for the 'inclusion' of people with disability in communities. Importantly, Churches have paid little attention to the historical construction of 'exclusion'. This paper proposes that matrices of patriarchal theology and patriarchal ethics continue to sustain structural positions of societal exclusion for people with disability because of implicit assumptions and values in the matrices about difference and different bodies. By examining a conjunction between feminism and disability around the issue of embodiment, the paper contends that 'inclusion' needs to be explored through the formation and embracing of matrices of feminist theology and feminist ethics.

  12. The earth as a planet - Paradigms and paradoxes

    NASA Technical Reports Server (NTRS)

    Anderson, D. L.

    1984-01-01

    The independent growth of the various branches of the earth sciences in the past two decades has led to a divergence of geophysical, geochemical, geological, and planetological models for the composition and evolution of a terrestrial planet. Evidence for differentiation and volcanism on small planets and a magma ocean on the moon contrasts with hypotheses for a mostly primitive, still undifferentiated, and homogeneous terrestrial mantle. In comparison with the moon, the earth has an extraordinarily thin crust. The geoid, which should reflect convection in the mantle, is apparently unrelated to the current distribution of continents and oceanic ridges. If the earth is deformable, the whole mantle should wander relative to the axis of rotation, but the implications of this are seldom discussed. The proposal of a mantle rich in olivine violates expectations based on evidence from extraterrestrial sources. These and other paradoxes force a reexamination of some long-held assumptions.

  13. Paradoxical Embolus Stuck in a Patent Foramen Ovale

    PubMed Central

    Kohistani, Zaki; Probst, Chris

    2016-01-01

    In-hospital mortality rate of an embolus in transit is as high as 44.7%. In some cases, a paradoxical embolus can get stuck in a patent foramen ovale. Because of the high mortality rate, this condition should be considered as an emergency case. Echocardiography has been established as the gold standard method for the diagnosis. A negative echocardiography, however, does not rule out an embolus in transit. To rule out pulmonary embolisms, a computed tomography scan of the chest should also be performed. A cardiothoracic surgeon should be consulted immediately upon diagnosis of an embolus in transit. There is no medical consensus for the treatment of the above mentioned condition, however, surgical treatment appears to be the best approach in patients who are surgical candidates. PMID:28018828

  14. The IRB paradox: could the protectors also encourage deceit?

    PubMed

    Keith-Spiegel, Patricia; Koocher, Gerald P

    2005-01-01

    The efforts of some institutional review boards (IRBs) to exercise what is viewed as appropriate oversight may contribute to deceit on the part of investigators who feel unjustly treated. An organizational justice paradigm provides a useful context for exploring why certain IRB behaviors may lead investigators to believe that they have not received fair treatment. These feelings may, in turn, lead to intentional deception by investigators that IRBs will rarely detect. Paradoxically, excessive protective zeal by IRBs may actually encourage misconduct by some investigators. The authors contend that, by fostering a climate in which investigators perceive that they receive fair and unbiased treatment, IRBs optimize the likelihood of collegial compliance with appropriate participant protections.

  15. Paradoxical Embolism due to Persistent Foramen Ovale; a Case Report

    PubMed Central

    Barrios, Dormar David; Roncancio, Jonathan; Avila, Albert Alejandro; Alvarado, Jaime Andrés; Montenegro, Ana Cristina

    2017-01-01

    The mean percentage of cryptogenic strokes among ischemic strokes is 31%, of which one-third may be associated with patent foramen ovale. The foramen ovale is required for blood flow through the fetal atrial septum. It is formed as of the fourth week of gestation, and this leads to right-left interatrial shunt that allows the passage of oxygenated blood to systemic circulation. In 75% of cases, its closure is complete by 2 years of age, but it may persist in 25% of patients. We present the case of a patient with paradoxical embolism in the lower extremities and ischemic stroke in the clinical context of a patent foramen ovale. PMID:28286853

  16. A unified approach to resolving the entropy production paradox

    NASA Astrophysics Data System (ADS)

    Hoffmann, Karl Heinz; Essex, Christopher; Prehl, Janett

    2012-12-01

    Bridging the regime between fully irreversible and fully reversible dynamics as represented by the two paradigmatic evolution equations for diffusion and wave propagation became possible by the use of fractional diffusion equations based on time- or space-fractional differential operators. These bridges are each characterized by a one-parameter family of distribution functions. In both cases one encounters a counter-intuitive behavior: the closer one gets to the reversible case, the larger the entropy production becomes. This feature is known as the entropy production paradox, and could be partly resolved for the time-fractional case by using the distribution mean as a way to characterize the internal quickness of the process, while for the space-fractional case a special location parameter was used. Here we are able to present a unified approach based on the distribution modes as the appropriate measure for the internal quickness of the processes.

  17. When in doubt, shout! paradoxical influences of doubt on proselytizing.

    PubMed

    Gal, David; Rucker, Derek D

    2010-11-01

    A seminal case study by Festinger found, paradoxically, that evidence that disconfirmed religious beliefs increased individuals' tendency to proselytize to others. Although this finding is renowned, surprisingly, it has never been subjected to experimental scrutiny and is open to multiple interpretations. We examined a general form of the question first posed by Festinger, namely, how does shaken confidence influence advocacy? Across three experiments, people whose confidence in closely held beliefs was undermined engaged in more advocacy of their beliefs (as measured by both advocacy effort and intention to advocate) than did people whose confidence was not undermined. The effect was attenuated when individuals affirmed their beliefs, and was moderated by both importance of the belief and open-mindedness of a message recipient. These findings not only have implications for the results of Festinger's seminal study, but also offer new insights into people's motives for advocating their beliefs.

  18. Towards a Resolution of the New Core Paradox

    NASA Astrophysics Data System (ADS)

    Driscoll, P. E.; Davies, C. J.

    2015-12-01

    Paleomagnetic observations that indicate a geodynamo as old as 4.2 Gyr are at odds with the "new core paradox", which claims insufficient energy to drive the ancient geodynamo prior to inner core nucleation. Recent upward revisions to the thermal conductivity of iron in the core strain the energy budget by increasing the conductive heat flow that must be overcome in order to drive thermal convection and maintain an ancient geodynamo. We address this paradox by computing thermal-magnetic evolutions of the Earth using a 1-D model with parameterizations for heat sources and sinks in the mantle and core. This model includes a number of important new features that have not been previous coupled in a single model. New features in the mantle model include enhanced mantle heat loss to due extrusive volcanism, crust formation and insolation, and latent heating due to magma ocean solidification. New features in the core model include realistic iron conductivities, time-dependent partitioning of light elements (O, S, and Si) between solid and liquid and their effect on the liquidus depression and gravitational energy release. Core evolutions derived from an energy model are compared to an energy-entropy model, which accounts for ohmic dissipation. We identify the conditions necessary to avoid shut-down of the geodynamo prior to inner core nucleation and to maintain a strong magnetic field over the last 4.2 Gyr. Using a dipole field scaling law derived from numerical dynamo models we compare the predicted paleo-dipole intensity to the paleointensity record and speculate on possible observational evidence for the inner core nucleation event.

  19. Paradoxical Roles of Antioxidant Enzymes: Basic Mechanisms and Health Implications.

    PubMed

    Lei, Xin Gen; Zhu, Jian-Hong; Cheng, Wen-Hsing; Bao, Yongping; Ho, Ye-Shih; Reddi, Amit R; Holmgren, Arne; Arnér, Elias S J

    2016-01-01

    Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are generated from aerobic metabolism, as a result of accidental electron leakage as well as regulated enzymatic processes. Because ROS/RNS can induce oxidative injury and act in redox signaling, enzymes metabolizing them will inherently promote either health or disease, depending on the physiological context. It is thus misleading to consider conventionally called antioxidant enzymes to be largely, if not exclusively, health protective. Because such a notion is nonetheless common, we herein attempt to rationalize why this simplistic view should be avoided. First we give an updated summary of physiological phenotypes triggered in mouse models of overexpression or knockout of major antioxidant enzymes. Subsequently, we focus on a series of striking cases that demonstrate "paradoxical" outcomes, i.e., increased fitness upon deletion of antioxidant enzymes or disease triggered by their overexpression. We elaborate mechanisms by which these phenotypes are mediated via chemical, biological, and metabolic interactions of the antioxidant enzymes with their substrates, downstream events, and cellular context. Furthermore, we propose that novel treatments of antioxidant enzyme-related human diseases may be enabled by deliberate targeting of dual roles of the pertaining enzymes. We also discuss the potential of "antioxidant" nutrients and phytochemicals, via regulating the expression or function of antioxidant enzymes, in preventing, treating, or aggravating chronic diseases. We conclude that "paradoxical" roles of antioxidant enzymes in physiology, health, and disease derive from sophisticated molecular mechanisms of redox biology and metabolic homeostasis. Simply viewing antioxidant enzymes as always being beneficial is not only conceptually misleading but also clinically hazardous if such notions underpin medical treatment protocols based on modulation of redox pathways.

  20. The paradox of algal blooms in oligotrophic waters

    NASA Astrophysics Data System (ADS)

    Sundareshwar, P. V.; Upadhyay, S.; Abessa, M. B.; Honomichl, S.; Berdanier, B.; Spaulding, S.; Sandvik, C.; Trennepohl, A.

    2010-12-01

    Nutrient inputs to streams and lakes, primarily from anthropogenic sources, lead to eutrophic conditions that favor algal blooms with undesirable consequences. In contrast, low nutrient or oligotrophic waters rarely support algal blooms; such ecosystems are typically lower in productivity. Since the mid-1980’s however, the diatom Didymosphenia geminata has dramatically expanded its range colonizing oligotrophic rivers worldwide with blooms appearing as thick benthic mats. This recent global occurrence of Didymosphenia geminata blooms in temperate rivers has been perplexing in its pace of spread and the paradoxical nature of the nuisance growths. The blooms occur primarily in oligotrophic flowing waters, where phosphorus (P) availability often limits primary production. We present a biogeochemical process by which D. geminata mats adsorb both P and iron (Fe) from flowing waters and make P available for cellular uptake. The adsorbed P becomes bioavailable through biogeochemical processes that occur within the mat. The biogeochemical processes observed here while well accepted in benthic systems are novel for algal blooms in lotic habits. Enzymatic and bacterial processes such as Fe and sulfate reduction can release the adsorbed P and increase its bioavailability, creating a positive feedback between total stalk biomass and nutrient availability. Stalk affinity for Fe, Fe-P biogeochemistry, and interaction between watershed processes and climatic setting explain the paradoxical blooms, and the recent global spread of this invasive aquatic species. At a broader scale the study also implies that such algal blooms in oligotrophic environments can fundamentally alter the retention and longitudinal transfer of important nutrients such as P in streams and rivers.

  1. Rock index properties for geoengineering in the Paradox Basin

    SciTech Connect

    O'Rourke, J.E.; Rey, P.H.; Alviti, E.; Capps, C.C.

    1986-02-01

    Previous researchers have investigated the use of a number of rapid index tests that can be used on core samples, or in situ, to determine rock properties needed for geoengineering design, or to predict construction performance in these rock types. Selected research is reviewed, and the correlations of index tests with laboratory tests of rock properties found by the earlier investigators are discussed. The selection and testing of rock core samples from the Gibson Dome No. 1 borehole in Paradox Basin are described. The samples consist primarily of non-salt rock above salt cycle 6, but include some samples of anhydrite and salt cycle 6. The index tests included the point load test, Schmidt hammer rebound test, and abrasion hardness test. Statistical methods were used to analyze the correlations of index test data with laboratory test data of rock properties for the same core. Complete statistical results and computer-generated graphics are presented; these results are discussed in relation to the work of earlier investigations for index testing of similar rock types. Generally, fair to good correlations were obtained for predicting unconfined compressive strength and Young's modulus for sandstone and siltstone, while poorer correlations were found for limestone. This may be due to the large variability of limestone properties compared to the small number of samples. Overall, the use of index tests to assess rock properties at Paradox Basin appears to be practial for some conceptual and preliminary design needs, and the technique should prove useful at any salt repository site. However, it is likely that specific correlations should be demonstrated separately for each site, and the data base for establishing the correlations should probably include at least several hundred data points for each type.

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

    PubMed

    Cirković, Milan M; Vukotić, Branislav

    2008-12-01

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

  3. The obese healthy paradox: is inflammation the answer?

    PubMed

    Barbarroja, Nuria; López-Pedrera, Rosario; Mayas, Maria Dolores; García-Fuentes, Eduardo; Garrido-Sánchez, Lourdes; Macías-González, M; El Bekay, Rajaa; Vidal-Puig, Antonio; Tinahones, Francisco J

    2010-08-15

    A paradoxical but common finding in the obesity clinic is the identification of individuals who can be considered 'inappropriately' healthy for their degree of obesity. We think that studying these obese but metabolically healthy individuals and comparing them with equally obese but insulin-resistant individuals could provide important insights into the mechanistic link between adipose tissue expansion and associated metabolic alterations. In the present study, we investigated whether there are differences in inflammatory and insulin signalling pathways in VAT (visceral adipose tissue) that could account for the metabolic differences exhibited by morbidly obese individuals who are either insulin-resistant (IR-MO) or paradoxically insulin-sensitive (NIR-MO). Our results indicate that there are pathways common to obesity and unrelated to insulin resistance and others that are discriminative for insulin resistance for a similar degree of obesity. For instance, all morbidly obese patients, irrespective of their insulin resistance, showed increased expression of TNFalpha (tumour necrosis factor alpha) and activation of JNK1/2 (c-Jun N-terminal kinase 1/2). However, the IR-MO group showed significantly elevated expression levels of IL (interleukin)-1beta and IL-6 and increased macrophage infiltrates compared with non-obese individuals and NIR-MO. IkappaBalpha [inhibitor of NF-kappaB (nuclear factor kappaB) alpha], the activation of ERK1/2 (extracellular-signal-regulated kinase 1/2) and NF-kappaB were discriminative of the state of insulin resistance and correlated with differential changes in IRS-1 (insulin receptor substrate 1) expression and Akt activation between IR-MO and NIR-MO individuals. Our results support the concept that NIR-MO individuals lack the inflammatory response that characterizes the IR-MO patient and that IL-6, IL-1beta, ERK and NF-kappaB are important effectors that mediate the inflammation effects promoting insulin resistance.

  4. Astrobiological Phase Transition: Towards Resolution of Fermi's Paradox

    NASA Astrophysics Data System (ADS)

    Ćirković, Milan M.; Vukotić, Branislav

    2008-12-01

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

  5. A proposed new approach and unified solution to old Pb paradoxes

    NASA Astrophysics Data System (ADS)

    Castillo, Paterno R.

    2016-05-01

    One of the most remarkable features of many and, perhaps, all oceanic basalts is that their Pb isotopic ratios (206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb) are too radiogenic to be coming from the undifferentiated mantle or bulk silicate Earth. This has created three major concerns in the behavior of U, Th and Pb in the Earth's mantle that have been termed the Pb paradoxes. These are the unexpectedly long time-integrated high U/Pb (1st paradox), long time-integrated low Th/U (2nd paradox) and constant Ce/Pb and Nb/U (3rd paradox) in the mantle sources of oceanic basalts. The origins of such unexpected ratios have been the object of intense studies that produced several highly significant, but generally individualized results during the last four decades. Detailed analysis of available data shows that the paradoxes are closely interrelated as they all pertain to the mantle and have many common characteristic features. Thus, the Pb paradoxes constitute a system of equations that must be solved all together as each solution must satisfy every equation in the system. For example, compositional data for the voluminous mid-ocean ridge basalts (MORB) show that the 1st and 2nd paradoxes exhibit a long time-integrated enrichment of U and the Th/U and Nb/Th ratios are also constant. A single solution to simultaneously explain the paradoxes in MORB is possible if recycled materials with variable enrichments in incompatible trace elements, particularly U and its daughter Pb* plus Nb, Ce, and Th are added to or mixed with the depleted upper mantle. Significantly, a similar binary mixing solution has been proposed for the Pb paradoxes in ocean island basalts.

  6. Massive Hemorrhage From Multiple Hepatic Artery Aneurysms.

    PubMed

    Kahn, S Lowell; McClain, Jonathan; Kaufman, Jeffrey L

    2016-10-01

    A 66-year-old man, with an abnormal porta hepatis, consistent with tumor or inflammation, developed massive bleeding from one of numerous hepatic artery aneurysms, and coil embolization achieved control of bleeding. He died of subsequent multisystem organ failure, and the most likely diagnosis was either polyarteritis nodosa or segmental arterial mediolysis. Although the dual hepatic blood supply allows a degree of arterial embolization, this case demonstrates the risks associated with large territory hepatic arterial embolization in the presence of hemodynamic instability. We discuss the management issues related to massive hepatic bleeding when no surgical approach is possible.

  7. Factors associated with massive fibrosis in silicosis.

    PubMed Central

    Ng, T P; Chan, S L

    1991-01-01

    Data on 1432 patients with silicosis on a register in Hong Kong were analysed to examine the association of massive fibrosis with possible predisposing factors. Detailed occupational and clinical histories, clinical records, radiographic readings according to the International Standard Classification of Radiographs of Pneumoconioses, and environmental dust measurements from hygiene surveys were used to obtain information for several variables--namely, age at first exposure, relative dust exposure level, duration of exposure, smoking, previous recorded history of tuberculosis, and background profusion of small opacities. The most significant risk factors associated with massive fibrosis were high relative dust exposure level, a history of tuberculosis, and increased background profusion of small opacities. PMID:2038729

  8. Primordial Li abundance and massive particles

    SciTech Connect

    Latin-Capital-Letter-Eth apo, H.

    2012-10-20

    The problem of the observed lithium abundance coming from the Big Bang Nucleosynthesis is as of yet unsolved. One of the proposed solutions is including relic massive particles into the Big Bang Nucleosynthesis. We investigated the effects of such particles on {sup 4}HeX{sup -}+{sup 2}H{yields}{sup 6}Li+X{sup -}, where the X{sup -} is the negatively charged massive particle. We demonstrate the dominance of long-range part of the potential on the cross-section.

  9. Physics of Mass Loss in Massive Stars

    NASA Astrophysics Data System (ADS)

    Puls, Joachim; Sundqvist, Jon O.; Markova, Nevena

    2015-01-01

    We review potential mass-loss mechanisms in the various evolutionary stages of massive stars, from the well-known line-driven winds of O-stars and BA-supergiants to the less-understood winds of Red Supergiants. We discuss optically thick winds from Wolf-Rayet stars and Very Massive Stars, and the hypothesis of porosity-moderated, continuum-driven mass loss from stars formally exceeding the Eddington limit, which might explain the giant outbursts from Luminous Blue Variables. We finish this review with a glance on the impact of rapid rotation, magnetic fields and small-scale inhomogeneities in line-driven winds.

  10. NON-AQUEOUS DISSOLUTION OF MASSIVE PLUTONIUM

    DOEpatents

    Reavis, J.G.; Leary, J.A.; Walsh, K.A.

    1959-05-12

    A method is presented for obtaining non-aqueous solutions or plutonium from massive forms of the metal. In the present invention massive plutonium is added to a salt melt consisting of 10 to 40 weight per cent of sodium chloride and the balance zinc chloride. The plutonium reacts at about 800 deg C with the zinc chloride to form a salt bath of plutonium trichloride, sodium chloride, and metallic zinc. The zinc is separated from the salt melt by forcing the molten mixture through a Pyrex filter.

  11. Olivier Chesneau's Work on Massive Stars

    NASA Astrophysics Data System (ADS)

    Millour, F.

    2015-12-01

    Olivier Chesneau challenged several fields of observational stellar astrophysics with bright ideas and an impressive amount of work to make them real in the span of his career, from his first paper on P Cygni in 2000, up to his last one on V838 Mon in 2014. He was using all the so-called high-angular resolution techniques since it helped his science to be made, namely study in details the inner structure of the environments around stars, be it small mass (AGBs), more massive (supergiant stars), or explosives (Novae). I will focus here on his work on massive stars.

  12. Convective lofting links Indian Ocean air pollution to paradoxical South Atlantic ozone maxima

    NASA Technical Reports Server (NTRS)

    Chatfield, R. B.; Guan, H.; Thompson, A. M.; Witte, J. C.

    2005-01-01

    We describe a broad resolution of the Atlantic Parado concerning the seasonal and geographic distribution, of tropical tropospheric ozone. We highlight periods of significant maximum tropospheric O3 for Jan.- April, 1999, exploiting satellite estimates and SHADOZ (Southern Hemisphere Additional Ozonesondes). Trajectory analyses connecting sondes and Total Tropospheric Ozone (TTO) maps suggest a complex influence from the Indian Ocean: beginning with mixed combustion sources, then low level transport, cumulonimbus venting, possible stratospheric input, and finally high-level transport to the west, with possible mixing over Africa. For the Jan.-March highest column-O3 periods in the Atlantic, distinct sounding peaks trace to specific NO sources, especially lightning, while in the same episodes, recurring every 20-50 days, more diffuse buildups of Indian-to-Atlantic pollution make important contributions.

  13. Convective lofting links Indian Ocean air pollution to paradoxical South Atlantic ozone maxima

    NASA Astrophysics Data System (ADS)

    Chatfield, R. B.; Guan, H.; Thompson, A. M.; Witte, J. C.

    2004-03-01

    We describe a broad resolution of the ``Atlantic Parado'' concerning the seasonal and geographic distribution of tropical tropospheric ozone. We highlight periods of significant maximum tropospheric O3 for Jan.-April, 1999, exploiting satellite estimates and SHADOZ (Southern Hemisphere Additional Ozonesondes). Trajectory analyses connecting sondes and Total Tropospheric Ozone (TTO) maps suggest a complex influence from the Indian Ocean: beginning with mixed combustion sources, then low level transport, cumulonimbus venting, possible stratospheric input, and finally high-level transport to the west, with possible mixing over Africa. For the Jan.-March highest column-O3 periods in the Atlantic, distinct sounding peaks trace to specific NO sources, especially lightning, while in the same episodes, recurring every 20-50 days, more diffuse buildups of Indian-to-Atlantic pollution make important contributions.

  14. e-Health in the Age of Paradox: A Position Paper

    NASA Astrophysics Data System (ADS)

    McIver, William

    This position paper examines a critical paradox in e-health: there is a striking gap between critical information services for health care that can be implemented today using existing in information and communication technologies and those services that are actually available. Facets of this paradox are examined in the context of Canadian analyses and policy, advanced research on health care reform, and current technological developments. Hypothetical scenarios are employed as a means of discussing the paradox and, ultimately, of describing potential solutions that are feasible now.

  15. Device- and semi-device-independent random numbers based on noninequality paradox

    NASA Astrophysics Data System (ADS)

    Li, Hong-Wei; Pawłowski, Marcin; Rahaman, Ramij; Guo, Guang-Can; Han, Zheng-Fu

    2015-08-01

    In this work, we propose device-independent true random number expansion protocols based on noninequality paradoxes such as Hardy's and Cabello's nonlocality arguments, thus highlighting the noninequality paradox as an important resource for device-independent quantum-information processing, in particular for generating true randomness. As a byproduct, we find that the nonlocal bound of the Cabello argument with arbitrary dimension is the same as the one achieved in the qubits system. More interestingly, we propose a dimension witness paradox based on the Cabello argument which can be used for constructing a semi-device-independent true random number expansion protocol.

  16. A joint analysis of the Drake equation and the Fermi paradox

    NASA Astrophysics Data System (ADS)

    Prantzos, Nikos

    2013-07-01

    I propose a unified framework for a joint analysis of the Drake equation and the Fermi paradox, which enables a simultaneous, quantitative study of both of them. The analysis is based on a simplified form of the Drake equation and on a fairly simple scheme for the colonization of the Milky Way. It appears that for sufficiently long-lived civilizations, colonization of the Galaxy is the only reasonable option to gain knowledge about other life forms. This argument allows one to define a region in the parameter space of the Drake equation, where the Fermi paradox definitely holds (`Strong Fermi paradox').

  17. 'Obesity paradox' misunderstands the biology of optimal weight throughout the life cycle.

    PubMed

    Dixon, J B; Egger, G J; Finkelstein, E A; Kral, J G; Lambert, G W

    2015-01-01

    The 'obesity paradox' refers to observations that run counter to the thesis that normal weight (BMI 18.5-24.9 g/m(2)) provides the lowest mortality and higher weight is associated with greater mortality. We argue that the weight of lowest mortality is influenced by aging and chronic disease, with mortality advantage extending into the overweight and even class I obese ranges under some circumstances. A focus on quality nutrition, physical activity, fitness, and maintaining function in these weight ranges may be preferable to a focus on intentional weight loss, which has uncertain effects. The 'obesity paradox' is no 'paradox' if one defines and interprets 'ideal' weight appropriately.

  18. Interactions in Massive Colliding Wind Binaries

    NASA Technical Reports Server (NTRS)

    Corcoran, M.

    2012-01-01

    The most massive stars (M> 60 Solar Mass) play crucial roles in altering the chemical and thermodynamic properties of their host galaxies. Stellar mass is the fundamental stellar parameter that determines their ancillary properties and which ultimately determines the fate of these stars and their influence on their galactic environs. Unfortunately, stellar mass becomes observationally and theoretically less well constrained as it increases. Theory becomes uncertain mostly because very massive stars are prone to strong, variable mass loss which is difficult to model. Observational constraints are uncertain too. Massive stars are rare, and massive binary stars (needed for dynamical determination of mass) are rarer still: and of these systems only a fraction have suitably high orbital inclinations for direct photometric and spectroscopic radial-velocity analysis. Even in the small number of cases in which a high-inclination binary near the upper mass limit can be identified, rotational broadening and contamination of spectral line features from thick circumstellar material (either natal clouds or produced by strong stellar wind driven mass loss from one or both of he stellar components) biases the analysis. In the wilds of the upper HR diagram, we're often left with indirect and circumstantial means of determining mass, a rather unsatisfactory state of affairs.

  19. Evolutionary tracks of massive stars during formation

    NASA Astrophysics Data System (ADS)

    Smith, Michael D.

    2014-02-01

    A model for massive stars is constructed by piecing together evolutionary algorithms for the protostellar structure, the environment, the inflow and the radiation feedback. We investigate specified accretion histories of constant, decelerating and accelerating forms and consider both hot and cold accretion, identified with spherical free-fall and disc accretion, respectively. Diagnostic tools for the interpretation of the phases of massive star formation and testing the evolutionary models are then developed. Evolutionary tracks able to fit Herschel Space Telescope data require the generated stars to be three to four times less massive than in previous interpretations, thus being consistent with clump star formation efficiencies of 10-15 per cent. However, for these cold Herschel clumps, the bolometric temperature is not a good diagnostic to differentiate between accretion models. We also find that neither spherical nor disc accretion can explain the high radio luminosities of many protostars. Nevertheless, we discover a solution in which the extreme ultraviolet flux needed to explain the radio emission is produced if the accretion flow is via free-fall on to hotspots covering less than 10 per cent of the surface area. Moreover, the protostar must be compact, and so has formed through cold accretion. We show that these conclusions are independent of the imposed accretion history. This suggests that massive stars form via gas accretion through discs which, in the phase before the star bloats, download their mass via magnetic flux tubes on to the protostar.

  20. Embeddings of the "New Massive Gravity"

    NASA Astrophysics Data System (ADS)

    Dalmazi, D.; Mendonça, E. L.

    2016-07-01

    Here we apply different types of embeddings of the equations of motion of the linearized "New Massive Gravity" in order to generate alternative and even higher-order (in derivatives) massive gravity theories in D=2+1. In the first part of the work we use the Weyl symmetry as a guiding principle for the embeddings. First we show that a Noether gauge embedding of the Weyl symmetry leads to a sixth-order model in derivatives with either a massive or a massless ghost, according to the chosen overall sign of the theory. On the other hand, if the Weyl symmetry is implemented by means of a Stueckelberg field we obtain a new scalar-tensor model for massive gravitons. It is ghost-free and Weyl invariant at the linearized level around Minkowski space. The model can be nonlinearly completed into a scalar field coupled to the NMG theory. The elimination of the scalar field leads to a nonlocal modification of the NMG. In the second part of the work we prove to all orders in derivatives that there is no local, ghost-free embedding of the linearized NMG equations of motion around Minkowski space when written in terms of one symmetric tensor. Regarding that point, NMG differs from the Fierz-Pauli theory, since in the latter case we can replace the Einstein-Hilbert action by specific f(R,Box R) generalizations and still keep the theory ghost-free at the linearized level.

  1. Massive Open Online Courses and Economic Sustainability

    ERIC Educational Resources Information Center

    Liyanagunawardena, Tharindu R.; Lundqvist, Karsten O.; Williams, Shirley A.

    2015-01-01

    Millions of users around the world have registered on Massive Open Online Courses (MOOCs) offered by hundreds of universities (and other organizations) worldwide. Creating and offering these courses costs thousands of pounds. However, at present, revenue generated by MOOCs is not sufficient to offset these costs. The sustainability of MOOCs is a…

  2. Assessment in Massive Open Online Courses

    ERIC Educational Resources Information Center

    Admiraal, Wilfried; Huisman, Bart; Pilli, Olga

    2015-01-01

    Open online distance learning in higher education has quickly gained popularity, expanded, and evolved, with Massive Open Online Courses (MOOCs) as the most recent development. New web technologies allow for scalable ways to deliver video lecture content, implement social forums and track student progress in MOOCs. However, we remain limited in…

  3. A Taxonomy of Massive Open Online Courses

    ERIC Educational Resources Information Center

    Pilli, Olga; Admiraal, Wilfried

    2016-01-01

    Massive Open Online Courses (MOOCs) as a new approach to distance education, which originated from the open education resources (OER) movement, are becoming widespread throughout the world. Over time, early versions of cMOOCs have undergone changes in terms of use, name and structure. In their short life, MOOCs have been categorized into different…

  4. The Fate of Massive Closed Strings

    SciTech Connect

    Chen Bin; Li Miao; She Jianhuang

    2005-12-02

    We calculate the semi-inclusive decay rate of an average string state with toroidal compactification in the the superstring theory. We also apply this calculation to a brane-inflation model in a warped geometry and find that the decay rate is greatly suppressed if the final strings are both massive and enhanced for massless radiation.

  5. Recovery From Giant Eruptions in Massive Stars

    NASA Astrophysics Data System (ADS)

    Kashi, A.; Davidson, K.; Humphreys, R. M.

    2015-12-01

    We perform radiation hydrodynamic simulations to study how very massive stars recover from giant eruptions. The post eruption star experience strong mass loss due to strong winds, driven by radial pulsations in the star*s interior, that operate by the κ-mechanism. The mass loss history obtained in our simulations resembles η Car*s history.

  6. Radial Infall onto a Massive Molecular Filament

    NASA Astrophysics Data System (ADS)

    Battersby, Cara; Myers, Philip C.; Shirley, Yancy L.; Keto, Eric; Kirk, Helen

    The newly discovered Massive Molecular Filament (MMF) G32.02+0.05 (~ 70 pc long, 105 M⊙) has been shaped and compressed by older generations of massive stars. The similarity of this filament in physical structure (density profile, temperature) to much smaller star-forming filaments, suggests that the mechanism to form such filaments may be a universal process. The densest portion of the filament, apparent as an Infrared Dark Cloud (IRDC) shows a range of massive star formation signatures throughout. We investigate the kinematics in this filament and find widespread inverse P cygni asymmetric line profiles. These line asymmetries are interpreted as a signature of large-scale radial collapse. Using line asymmetries observed with optically thick HCO+ (1-0) and optically thin H13CO+ (1-0) across a range of massive star forming regions in the filament, we estimate the global radial infall rate of the filament to range from a few 100 to a few 1000 M⊙ Myr-1 pc-1. At its current infall rate the densest portions of the cloud will more than double their current mass within a Myr.

  7. NOTE: Circular symmetry in topologically massive gravity

    NASA Astrophysics Data System (ADS)

    Deser, S.; Franklin, J.

    2010-05-01

    We re-derive, compactly, a topologically massive gravity (TMG) decoupling theorem: source-free TMG separates into its Einstein and Cotton sectors for spaces with a hypersurface-orthogonal Killing vector, here concretely for circular symmetry. We then generalize the theorem to include matter; surprisingly, the single Killing symmetry also forces conformal invariance, requiring the sources to be null.

  8. The Dynamics of Massive Starless Cores

    NASA Astrophysics Data System (ADS)

    Tan, Jonathan; Caselli, P.; Fontani, F.; Kong, S.; Butler, M. J.

    2012-05-01

    Progress towards resolving a decade-long debate about how massive stars form can be made by determining if massive starless cores exist in a state of near virial equilibrium. These are the initial conditions invoked by the Core Accretion model of McKee & Tan (2003). Alternatively, the Competitive Accretion model of Bonnell et al. (2001) requires sub-virial conditions. We have identified 4 prime examples of massive ( 50 Msun) cores from mid-infrared (MIR) extinction mapping (Butler & Tan 2009, 2012) of Infrared Dark Clouds. We have found spectacularly high deuterated fractions of N_2H+ of 0.5 in these objects with the IRAM 30m telescope (Fontani et al. 2011). Thus N_2D+ is expected to be an excellent tracer of the kinematics of these cold, dark cores, where most other molecular tracers are thought to be depleted from the gas phase. We report on ALMA Cycle 0 Compact Configuration Band 6 observations of these 4 cores that probe the N_2D+(3-2) line on scales from 9" down to 2.3", well-matched to the structures we see in MIR extinction and discuss their implications for massive star formation theories.

  9. Modeling populations of rotationally mixed massive stars

    NASA Astrophysics Data System (ADS)

    Brott, I.

    2011-02-01

    Massive stars can be considered as cosmic engines. With their high luminosities, strong stellar winds and violent deaths they drive the evolution of galaxies through-out the history of the universe. Despite the importance of massive stars, their evolution is still poorly understood. Two major issues have plagued evolutionary models of massive stars until today: mixing and mass loss On the main sequence, the effects of mass loss remain limited in the considered mass and metallicity range, this thesis concentrates on the role of mixing in massive stars. This thesis approaches this problem just on the cross road between observations and simulations. The main question: Do evolutionary models of single stars, accounting for the effects of rotation, reproduce the observed properties of real stars. In particular we are interested if the evolutionary models can reproduce the surface abundance changes during the main-sequence phase. To constrain our models we build a population synthesis model for the sample of the VLT-FLAMES Survey of Massive stars, for which star-formation history and rotational velocity distribution are well constrained. We consider the four main regions of the Hunter diagram. Nitrogen un-enriched slow rotators and nitrogen enriched fast rotators that are predicted by theory. Nitrogen enriched slow rotators and nitrogen unenriched fast rotators that are not predicted by our model. We conclude that currently these comparisons are not sufficient to verify the theory of rotational mixing. Physical processes in addition to rotational mixing appear necessary to explain the stars in the later two regions. The chapters of this Thesis have been published in the following Journals: Ch. 2: ``Rotating Massive Main-Sequence Stars I: Grids of Evolutionary Models and Isochrones'', I. Brott, S. E. de Mink, M. Cantiello, N. Langer, A. de Koter, C. J. Evans, I. Hunter, C. Trundle, J.S. Vink submitted to Astronomy & Astrop hysics Ch. 3: ``The VLT-FLAMES Survey of Massive

  10. Positivity constraints for pseudolinear massive spin-2 and vector Galileons

    NASA Astrophysics Data System (ADS)

    Bonifacio, James; Hinterbichler, Kurt; Rosen, Rachel A.

    2016-11-01

    We derive analyticity constraints on a nonlinear ghost-free effective theory of a massive spin-2 particle known as pseudolinear massive gravity, and on a generalized theory of a massive spin-1 particle, both of which provide simple IR completions of Galileon theories. For pseudolinear massive gravity we find that, unlike de Rham, Gabadadze, and Tolley massive gravity, there is no window of parameter space which satisfies the analyticity constraints. For massive vectors which reduce to Galileons in the decoupling limit, we find that no two-derivative actions are compatible with positivity but that higher derivative actions can be made compatible.

  11. Stishovite paradox in genesis of the superdeep diamond

    NASA Astrophysics Data System (ADS)

    Litvin, Yuriy

    2013-04-01

    Stishovite was experimentally discovered [1] as high-density polymorph of SiO2 stable at 9 - 50 GPa. A paradoxical paragenesis of stishovite and magnesiowustite (Mg,Fe)O was disclosed among primary inclusions in lower-mantle superdeep diamonds [2]. This contradicts to a common knowledge that SiO2 and MgO paragenesis is forbidden for low-pressure SiO2 polymorphs - quartz and coesite. The "stishovite paradox" does not manifest itself in the lower mantle ultrabasic compositions as is seen from experimental pyrolite assembly magnesiowustite+Mg-perovskite+Ca-perovskite at 50 GPa. In basic basalt composition stishovite is formed together with Ca-perovskite, Mg-perovskite and Al-bearing phases under the lower mantle PT-parameters [3]. In this case stishovite is taken as product of oceanic basalt subducted into lower mantle, but not in situ lower-mantle primary mineral. Paragenesis of stishovite and superdeep diamond has opened up fresh opportunity for detailed study. Magnesiowustite (Mg,Fe)O inclusions in superdeep diamonds are characterized by a wide variation of FeO content between 10 and 64 mol. % [2]. It is interesting that ringwoodite (Mg,Fe)2SiO4 solid solutions are decomposed into Mg-perovskite (Mg,Fe)SiO3 + magnesiowustite (Mg,Fe)O + SiO2 (within 30 - 42 mol. % Fe2SiO4) and magnesiowustite + stishovite (within 42 - 100 mol. % Fe2SiO4). Based on experimental data, melting phase diagram of MgO - SiO2 - FeO system at 30 GPa is constructed [4]. Subsolidus assembly includes solid solutions of (Mg,Fe)-perovskite and (Mg,Fe)O. With increase in FeO content in the system, liquidus relations are determined by two univariant cotectics L + (Mg,Fe)O + (Mg,Fe)SiO3 and L + SiO2 + (Mg,Fe)SiO3 having come to invariant peritectic L + (Mg,Fe)O + SiO2 + (Mg,Fe)SiO3. Mg-perovskite is eliminated by peritectic reaction L + (Mg,Fe)SiO3 = (Mg,Fe)O + SiO2 that gives rise to third univariant cotectic L + (Mg,Fe)O + SiO2. The physicochemical peritectic mechanism is also operating in the Mg

  12. The Rb problem in massive AGB stars.

    NASA Astrophysics Data System (ADS)

    Pérez-Mesa, V.; García-Hernández, D. A.; Zamora, O.; Plez, B.; Manchado, A.; Karakas, A. I.; Lugaro, M.

    2017-03-01

    The asymptotic giant branch (AGB) is formed by low- and intermediate-mass stars (0.8 M_{⊙} < M < 8 M_{⊙}) in their last nuclear-burning phase, when they develop thermal pulses (TP) and suffer extreme mass loss. AGB stars are the main contributor to the enrichment of the interstellar medium (ISM) and thus to the chemical evolution of galaxies. In particular, the more massive AGB stars (M > 4 M_{⊙}) are expected to produce light (e.g., Li, N) and heavy neutron-rich s-process elements (such as Rb, Zr, Ba, Y, etc.), which are not formed in lower mass AGB stars and Supernova explosions. Classical chemical analyses using hydrostatic atmospheres revealed strong Rb overabundances and high [Rb/Zr] ratios in massive AGB stars of our Galaxy and the Magellanic Clouds (MC), confirming for the first time that the ^{22}Ne neutron source dominates the production of s-process elements in these stars. The extremely high Rb abundances and [Rb/Zr] ratios observed in the most massive stars (specially in the low-metallicity MC stars) uncovered a Rb problem; such extreme Rb and [Rb/Zr] values are not predicted by the s-process AGB models, suggesting fundamental problems in our present understanding of their atmospheres. We present more realistic dynamical model atmospheres that consider a gaseous circumstellar envelope with a radial wind and we re-derive the Rb (and Zr) abundances in massive Galactic AGB stars. The new Rb abundances and [Rb/Zr] ratios derived with these dynamical models significantly resolve the problem of the mismatch between the observations and the theoretical predictions of the more massive AGB stars.

  13. Evaporite cycles and cycle boundaries in the upper part of the Paradox Member, Hermosa Formation of Pennsylvanian age in the Paradox basin, Utah and Colorado

    SciTech Connect

    Raup, O.B.; Hite, R.J. )

    1991-03-01

    The evaporites of the Paradox Member of the Hermosa Formation of Pennsylvanian age in southeastern Utah and southwestern Colorado are direct precipitates from marine brines and have been changed only slightly by subsequent events. Geophysical logs of deep wells indicate that the Paradox Member is composed of at least 30 evaporite cycles. Lithologies that make up the cycles, in order of increasing salinity, are organic carbon-rich carbonate shale (black shale), dolomite, anhydrite, and halite (with or without potash). Studies of core from two wells in the central part of the basin show that some of the cycles in the upper part of the Paradox Member are remarkably symmetrical, indicating regular changes in salinity. Detailed petrologic studies have revealed newly recognized lithologic textures and cycle boundaries in 11 evaporite cycles, indicating very regular cyclicity of subaqueous sedimentation in a basin in which salinity was probably controlled by Gondwana glaciation.

  14. The Case for Massive and Ancient Rings of Saturn

    NASA Astrophysics Data System (ADS)

    Esposito, Larry W.

    2016-04-01

    Analysis of Voyager and Pioneer 11 results give a mass for Saturn's rings, M = 5 x 10-8 Msat. This is about the mass of Saturn's small moon Mimas. This has been interpreted as a lower limit to the ring mass (Esposito et al 1983), since the thickest parts of the rings were not penetrated by the stellar occultstion, and this calculation assumes an unvarying particle size throughout the rings. Because the rings are constantly bombarded by micrometeroids, their current composition of nearly pure water ice implies such low mass rings must have formed recently. The case is par-ticularly strong for Saturn's A ring, where the data are the best, implying the A ring is less than 10% of the age of the Saturn (Esposito 1986). Cassini results com-pound this problem. UVIS spectra are consistent with either young rings or rings about 10x as massive as the Voyager estimate (Elliott and Esposito (2011). CDA confirms the impacting mass flux is similar to that as-sumed for the pollution calculations (Kempf etal 2015). VIMS analysis of density wave signatures in the B ring gives a value of about 1/3 the Voyager value (Hedmann etal 2016). This VIMS result implies the rings are even younger! The problem is that young rings are very unlikely to be formed recently, meaning that we live in a very special epoch, following some unlikely recent origin… like disruption of a medium sized moon or capture of the fragments of a disrupted comet. This paradox (Charnoz etal 2009) is unre-solved. Alternative interpretations: To take the VIMS results at face value, Saturn's low mass rings must be very young. The optically thick B ring must be made of small, porous or fractal particles. This is hard to understand, since the particles are continually colliding every few hours and temporary aggregates will stir the collision velocities to higher values. An alternative is that we accept the higher mass interpretation of the Pioneer 11 results (Esposito etal 2008) using the granola bar model of Colwell

  15. Vavilov's Paradox: On Paper, It's a Violation of the Energy Conservation Law.

    ERIC Educational Resources Information Center

    Fabrikant, V. A.

    1992-01-01

    Discusses the energy flux-density of two beams of light of equal energy that are intersected at a given angle. Examines an apparent contradiction to the physics law of conservation of energy known as Vavilov's paradox. (MDH)

  16. Time travel paradoxes, path integrals, and the many worlds interpretation of quantum mechanics

    NASA Astrophysics Data System (ADS)

    Everett, Allen

    2004-06-01

    We consider two approaches to evading paradoxes in quantum mechanics with closed timelike curves. In a model similar to Politzer’s, assuming pure states and using path integrals, we show that the problems of paradoxes and of unitarity violation are related; preserving unitarity avoids paradoxes by modifying the time evolution so that improbable events become certain. Deutsch has argued, using the density matrix, that paradoxes do not occur in the “many worlds interpretation.” We find that in this approach account must be taken of the resolution time of the device that detects objects emerging from a wormhole or other time machine. When this is done one finds that this approach is viable only if macroscopic objects traversing a wormhole interact with it so strongly that they are broken into microscopic fragments.

  17. Generalized friendship paradox in complex networks: The case of scientific collaboration

    NASA Astrophysics Data System (ADS)

    Eom, Young-Ho; Jo, Hang-Hyun

    2014-04-01

    The friendship paradox states that your friends have on average more friends than you have. Does the paradox ``hold'' for other individual characteristics like income or happiness? To address this question, we generalize the friendship paradox for arbitrary node characteristics in complex networks. By analyzing two coauthorship networks of Physical Review journals and Google Scholar profiles, we find that the generalized friendship paradox (GFP) holds at the individual and network levels for various characteristics, including the number of coauthors, the number of citations, and the number of publications. The origin of the GFP is shown to be rooted in positive correlations between degree and characteristics. As a fruitful application of the GFP, we suggest effective and efficient sampling methods for identifying high characteristic nodes in large-scale networks. Our study on the GFP can shed lights on understanding the interplay between network structure and node characteristics in complex networks.

  18. Flow in a porous nozzle with massive wall injection

    NASA Technical Reports Server (NTRS)

    Kinney, R. B.

    1973-01-01

    An analytical and experimental investigation has been conducted to determine the effect of massive wall injection on the flow characteristics in a nozzle. The experiments were performed on a water table with a porous-nozzle test section. This had 45 deg and 15 deg half angles of convergence and divergence, respectively, throat radius of 2.5 inches, and throat width of 3 inches. The hydraulic analogy was employed to qualitatively extend the results to a compressible gas flow through the nozzle. An analysis of the water table flow was made using a one-dimensional flow assumption in the continuity and momentum equations. An analysis of a compressible flow in a nozzle was made in a manner analogous to that for the water flow. It is shown that the effect of blowing is to move the sonic position downstream of the geometric throat. Similar results were determined for the incompressible water table flow. Limited photographic results are presented for an injection of air, CO2, and Freon-12 into a main-stream air flow in a convergent-divergent nozzle. Schlieren photographs were used to visualize the flow.

  19. Evaluation of hydrogeologic aspects of proposed salinity control in Paradox Valley, Colorado

    USGS Publications Warehouse

    Konikow, Leonard F.; Bedinger, M.S.

    1978-01-01

    The salt load in the Dolores River increases by about 200,000 tons per year where it crosses Paradox Valley, Colorado, because of the discharge of a sodium chloride brine from an underlying aquifer. A ground-water management program to nearly eliminate this major source of salt, which eventually enters the Colorado River, can be designed on the basis of an accurate description of the hydrogeologic framework of Paradox Valley.

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

    NASA Astrophysics Data System (ADS)

    Melkikh, A. V.

    2017-01-01

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

  1. Paradoxes of photoconductive target and optical control of secondary ion yield

    SciTech Connect

    Rokakh, A. G. Matasov, M. D.

    2010-01-15

    This study of the photoconductivity of semiconductors, in particular, cadmium chalcogenides as materials for targets of vacuum image converters followed the path of overcoming paradoxes. The concepts developed by the classics of photoelectricity also help to understand the paradoxes of the new secondary-ion photoelectric effect, especially, its spectral characteristic. The optical channel of secondary ion yield control via a photoconductive target opens the way to a new branch of nanotechnology, i.e., optoionics.

  2. Spatial heterogeneity can resolve the nitrogen paradox of tropical forests.

    PubMed

    Menge, Duncan N L; Levin, Simon A

    2017-01-10

    Many tropical forests are characterized by large losses of plant-available forms of nitrogen (N), indicating that they are N-rich, and by an abundance of plants capable of symbiotic N fixation. These N-fixing plants can fix enough N to drive N-richness. However, biological N fixation (BNF) is more expensive than using plant-available N, so sustained BNF in N-rich soils appears to be a paradox. Here, we use spatially explicit ecosystem models to analyze the conditions under which spatial heterogeneity can induce simultaneous BNF and loss of plant-available N (hereafter, we call this combination "N-rich BNF"). Spatial movement of litter to neighboring plants' rooting zones can maintain N-rich BNF under a variety of conditions. For example, when N-fixers have higher N demand than non-fixers, N-fixers export N-rich litter to non-fixers, inducing large losses of plant-available N from the ecosystem, and receive N-poor litter from non-fixers, inducing BNF. BNF and N loss fluxes increase in proportion to the ratio of N-fixer litter N:P to non-fixer litter N:P, and also in proportion to the fraction of litter transferred out of a tree's rooting zone. Stoichiometric variability augments N-rich BNF, as does increasing the fraction of the landscape occupied by N-fixers, at least when they are rare. On the contrary, greater root overlap between neighbors and clumping of N-fixers diminish N-rich BNF. Finally, we examined how spatial litter transfer interacts with another mechanism that can sustain N-rich BNF, incomplete down-regulation of BNF. Spatial transfer and incomplete down-regulation can both sustain N-rich BNF, but they are compensatory rather than additive. These mechanisms can be distinguished by examining where N losses occur. Incomplete down-regulation of BNF leads to greater N loss under N-fixing trees, whereas spatial litter transfer leads to greater N loss under non-fixing trees. Along with time lags in regulating BNF, these results comprise a series of

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

    PubMed

    Jung, Keum Ji; Jeon, Christina; Jee, Sun Ha

    2016-01-01

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

  4. Paradoxical activity of beta-lactam antibiotics against Proteus vulgaris in experimental infection in mice.

    PubMed

    Ikeda, Y; Fukuoka, Y; Motomura, K; Yasuda, T; Nishino, T

    1990-01-01

    In previous papers (Y. Ikeda and T. Nishino, Antimicrob. Agents Chemother. 32:1073-1077, 1988; Y. Ikeda, T. Nishino, and T. Tanino, Antimicrob. Agents Chemother. 31:865-869, 1987), we reported that many of the 7-aminothiazolyl cephalosporins, such as cefmenoxime, showed paradoxically reduced activity against Proteus vulgaris at higher concentrations, whereas these paradoxical effects were not observed for other types of cephalosporins, such as cefbuperazone and cefoperazone. In this study, we compare the therapeutic effect of cefmenoxime with that of cefbuperazone and explore the in vivo paradoxical effect of cefmenoxime by using an experimental infection model in mice. In an intraperitoneal infection with P. vulgaris 11, the survival rate with cefmenoxime was increased to 43% at 3.13 mg/kg but was lower at higher doses. On the other hand, cefbuperazone did not show such a paradoxical therapeutic effect. In mice infected with P. vulgaris 11, cefmenoxime levels in both serum and peritoneal washings were rapidly reduced and beta-lactamase activities in the peritoneal cavity were increased at higher cefmenoxime doses. These findings suggested that high levels of cefmenoxime at the infection site induced increased production of beta-lactamase, which then rapidly inactivated the antibiotic. We conclude that the paradoxical therapeutic effect of cefmenoxime against P. vulgaris occurs by the same mechanisms as the in vitro effect and that the high beta-lactamase inducibility and low beta-lactamase stability may account for the paradoxical therapeutic effect of cefmenoxime against P. vulgaris.

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

    PubMed Central

    2016-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Jones, Phillip N.; Cuper, Taryn

    2010-01-01

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

  7. SUPERDENSE MASSIVE GALAXIES IN WINGS LOCAL CLUSTERS

    SciTech Connect

    Valentinuzzi, T.; D'Onofrio, M.; Fritz, J.; Poggianti, B. M.; Bettoni, D.; Fasano, G.; Moretti, A.; Omizzolo, A.; Varela, J.; Cava, A.; Couch, W. J.; Dressler, A.; Moles, M.; Kjaergaard, P.; Vanzella, E.

    2010-03-20

    Massive quiescent galaxies at z > 1 have been found to have small physical sizes, and hence to be superdense. Several mechanisms, including minor mergers, have been proposed for increasing galaxy sizes from high- to low-z. We search for superdense massive galaxies in the WIde-field Nearby Galaxy-cluster Survey (WINGS) of X-ray selected galaxy clusters at 0.04 < z < 0.07. We discover a significant population of superdense massive galaxies with masses and sizes comparable to those observed at high redshift. They approximately represent 22% of all cluster galaxies more massive than 3 x 10{sup 10} M{sub sun}, are mostly S0 galaxies, have a median effective radius (R{sub e} ) = 1.61 +- 0.29 kpc, a median Sersic index (n) = 3.0 +- 0.6, and very old stellar populations with a median mass-weighted age of 12.1 +- 1.3 Gyr. We calculate a number density of 2.9 x 10{sup -2} Mpc{sup -3} for superdense galaxies in local clusters, and a hard lower limit of 1.3 x 10{sup -5} Mpc{sup -3} in the whole comoving volume between z = 0.04 and z = 0.07. We find a relation between mass, effective radius, and luminosity-weighted age in our cluster galaxies, which can mimic the claimed evolution of the radius with redshift, if not properly taken into account. We compare our data with spectroscopic high-z surveys and find that-when stellar masses are considered-there is consistency with the local WINGS galaxy sizes out to z {approx} 2, while a discrepancy of a factor of 3 exists with the only spectroscopic z > 2 study. In contrast, there is strong evidence for a large evolution in radius for the most massive galaxies with M{sub *} > 4 x 10{sup 11} M{sub sun} compared to similarly massive galaxies in WINGS, i.e., the brightest cluster galaxies.

  8. Massively Parallel Algorithms for Solution of Schrodinger Equation

    NASA Technical Reports Server (NTRS)

    Fijany, Amir; Barhen, Jacob; Toomerian, Nikzad

    1994-01-01

    In this paper massively parallel algorithms for solution of Schrodinger equation are developed. Our results clearly indicate that the Crank-Nicolson method, in addition to its excellent numerical properties, is also highly suitable for massively parallel computation.

  9. Paradox-Free FTL Travel in Higher Dimensional Spaces

    NASA Astrophysics Data System (ADS)

    Froning, H. David

    2004-02-01

    This paper describes one possibility for rapid round-trip, paradox-free Faster-than-Light (FTL) travel between Earth and distant stars within the human lifetimes of those on-board the ships and Earth. It shows that such rapid transits would require dimensions beyond the 4 dimensions of flat or curved spacetime; with the added dimensions needed to give starships (their worldlines) room to ``climb'' and ``descend'' above the spacetime realms of Special Relativity (SR)-realms where nothing travels faster than the speed-of-light (c). The added dimensions would be associated with zero-point field gradients formed within the quantum vacuum by actions of specially conditioned em radiation emitted from accelerating ships. These gradients would result in: STL (slower-than-light) vehicle velocity within the perturbed vacuum surrounding the ship; FTL vehicle velocity with respect to the unperturbed vacuum and Earth; and invisible FTL vehicle travel in all observer-frames that move STL with respect to Earth. For one case of FTL travel, rapid transits to distant stars would result in starship disappearance from human sight after light speed is reached-followed soon thereafter by its reappearance trillions of miles away, in close proximity to its target star. And during the short interval of disappearance, the starship's worldline would jump over trillions of miles of distance-arching like a suddenly-formed rainbow within a ``spacetimetau'' realm of existence that rises above curved or flat spacetime terrain.

  10. No climate paradox under the faint early Sun.

    PubMed

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

    2010-04-01

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

  11. Paradoxical Abatement of Striatal Dopaminergic Transmission by Cocaine and Methylphenidate*

    PubMed Central

    Federici, Mauro; Latagliata, Emanuele Claudio; Ledonne, Ada; Rizzo, Francesca R.; Feligioni, Marco; Sulzer, Dave; Dunn, Matthew; Sames, Dalibor; Gu, Howard; Nisticò, Robert; Puglisi-Allegra, Stefano; Mercuri, Nicola B.

    2014-01-01

    We combined in vitro amperometric, optical analysis of fluorescent false neurotransmitters and microdialysis techniques to unveil that cocaine and methylphenidate induced a marked depression of the synaptic release of dopamine (DA) in mouse striatum. In contrast to the classical dopamine transporter (DAT)-dependent enhancement of the dopaminergic signal observed at concentrations of cocaine lower than 3 μm, the inhibitory effect of cocaine was found at concentrations higher than 3 μm. The paradoxical inhibitory effect of cocaine and methylphenidate was associated with a decrease in synapsin phosphorylation. Interestingly, a cocaine-induced depression of DA release was only present in cocaine-insensitive animals (DAT-CI). Similar effects of cocaine were produced by methylphenidate in both wild-type and DAT-CI mice. On the other hand, nomifensine only enhanced the dopaminergic signal either in wild-type or in DAT-CI mice. Overall, these results indicate that cocaine and methylphenidate can increase or decrease DA neurotransmission by blocking reuptake and reducing the exocytotic release, respectively. The biphasic reshaping of DA neurotransmission could contribute to different behavioral effects of psychostimulants, including the calming ones, in attention deficit hyperactivity disorder. PMID:24280216

  12. The inherent paradox of clinical trials in psychiatry.

    PubMed Central

    Helmchen, H; Müller-Oerlinghausen, B

    1975-01-01

    The authors sum up the central issue of ethics in the conduct of controlled clinical trials in these two paradoxes: 'first, it is unethical to use treatment the efficacy of which has not been examined scientifically; second, it is also unethical to examine the efficacy of treatment scientifically.' In this paper they set out to demonstrate how these antithetical statements apply in controlled trials conducted in psychiatric patients. In such trials the problem of obtaining informed consent may be acute, but in these patients giving 'informed' consent might contribute to a further exacerbation of the illness. Nevertheless the problem cannot be evaded, and scientific judgments must be applied to treatment for it to be sound and improved for the further benefit of patients. These problems in the case of psychiatric controlled trials are a part of the methodology, and in Germany a new drug law has been drafted to attempt to clarify the issue. The authors briefly discuss its application, and its consequences if such a law were enacted. British psychiatrists have exactly the same problems to face but so far no attempts have been made to establish a legal framework. PMID:775089

  13. On Gray's paradox and efficiency measures for swimming

    NASA Astrophysics Data System (ADS)

    Bale, Rahul; Hao, Max; Bhalla, Amneet; Patankar, Neelesh

    2010-11-01

    In 1936 Gray reported that the "drag" power of dolphins was substantially larger than the estimates of muscle power. We revisit this "paradox" in the context of undulatory swimming. We consider larval zebrafish as a model system. We question the basic premise of comparing drag power to muscle power. There are two reasons. First, we recognize that it may not be possible decompose the net force on an undulatory swimmer into drag and thrust. If it becomes possible, as we show in our case, the drag power, which represents the work done on the fluid due to motion in the swimming direction, is exactly balanced by the thrust power, which represents the work done by the fluid. Thus, the total power in the swimming direction, computed in this way, is zero. Second, we show that most of the muscle energy is dissipated in causing the lateral motion of the body - not in overcoming the "drag" in the swimming direction. This will be shown based on a power balance equation. Thus, we argue that efficiency measures, that relate the drag power to muscle power, or the Froude efficiency, are not recommended. Instead non-dimensional cost-of-transport could be a useful measure to compare efficiencies of organisms at different scales.

  14. Paradoxical effects of cyclosporin A on collagen arthritis in rats

    PubMed Central

    1983-01-01

    The effect of the immunosuppressive agent cyclosporin A (CS-A) on collagen arthritis in Sprague-Dawley rats is investigated. A 14-d course of CS-A treatment at doses of 15 mg/kg per day or more, begun on the same day as type II collagen immunization, suppressed the development of arthritis as well as humoral and delayed-type hypersensitivity (DTH) skin test responses to type II collagen, possibly by interfering with helper T cells. Additional studies demonstrated that CS-A treatment only during the induction phase of immunity proved to be successful. When CS-A treatment was started only during the immediately preclinical phase of arthritis or after the disease onset, a significant enhancement of the disease was obtained in a dose-dependent manner. This enhancement was accompanied by an augmentation of DTH skin reactions, while antibody responses were either suppressed or unaffected. These results appear to be attributable at least in part to a suppressive effect of CS-A on a population of suppressor T cells, thus resulting in a T cell-mediated helper effect. It is therefore reasonable to assume that the paradoxical effects of CS-A on collagen arthritis in rats might be caused by an altering of the sensitive balance of the two regulatory subpopulations of T cells. It is also possible that cell-mediated immune responses may play an important role in influencing the course of the disease. PMID:6644238

  15. Paradoxical effects of education on the Iowa Gambling Task.

    PubMed

    Evans, Cathryn E Y; Kemish, Karen; Turnbull, Oliver H

    2004-04-01

    Suitable normative information on the Iowa Gambling Task (IGT) is not currently available, though it is clear that there is great individual variability in performance on this assessment tool. Given that the task is presumed to measure the emotion-based learning systems that are thought to form the biological basis of 'intuition,' there is some reason to think that education (especially tertiary education) might explicitly de-emphasise the role of emotion-based learning in decision-making. This suggests the paradoxical finding that better-educated participants should show poorer performance on the IGT. We recruited 30 participants (all female, all aged 18-25) to participate in a 'real money' version of the IGT. There was no significant difference in performance in blocks 1-3 of the task (trials 1-60). However, there was a substantial effect of education on the final two blocks (trials 61-100), such that the less-well-educated participants produced twice as much of an improvement over baseline as did their university-educated colleagues. A range of possible explanations for this remarkable finding are discussed. The most likely appears to be that tertiary education specifically discourages the use of emotion-based learning systems in decision-making. These findings bear on the extent to which education has a role to play in our reliance on cognition and emotion in decision-making, including the likely role of education in the generation and maintenance of false beliefs.

  16. Permanent administration of d-fenfluramine in rats: paradoxical effects.

    PubMed

    Rozen, R; Fumeron, F; Betoulle, D; Baigts, F; Mandenoff, A; Fricker, J; Apfelbaum, M

    1988-01-01

    In order to test the hypothesis of Levitzky that d-fenfluramine (d-F) acts by modifying the ponderal set-point, we compared the effects of a permanent infusion of d-F on food intake and body weight (BW). The effect on the weight persisted as long as the infusion; the clear-cut anorectic effect lasted only a few days. This paradox is compatible with the set-point hypothesis. In rats rendered overweight by insulin treatment, the d-F-induced decrease in BW was approximately four times smaller than in controls. In rats rendered overweight by a cafeteria diet, the decrease in BW was twice as large in permanently cafeteria fed rats as in cafeteria, then, ad lib fed rats. In rats rendered underweight by a restricted chow diet and then returned to an ad lib feeding, the final BW depended only on the doses of d-F (0.6 or 12 mg/kg BW/day), whatever the weight at the beginning of infusion. Thus, the underweight paradigm fits well with the set-point hypothesis; the overweight paradigm fits only partially.

  17. Rushton's paradox: rod dark adaptation after flash photolysis.

    PubMed Central

    Pugh, E N

    1975-01-01

    1. Rod dark adaptations after a photoregenerating flash and quantum-equivalent 30 sec bleach are found to be in exact agreement, while the measured rhodopsin regenerations are grossly different. This finding confirms and clarifies "Rushton's paradox', the failure of the Dowling-Rushton equation (linking log sensitivity linearly with unregenerated rhodopsin) to account for human rod dark adaptation after flash photolysis. 2. The hypothesis that the agreement between rod dark adaptation curves after a photoregenerating flash and after a quantum-equivalent 30 sec bleach is coincidental is rejected on the basic of two classes of experiments. 3. Rod "bleaching' adaptation is demonstrated to be entirely determined by the number of rhodopsin molecules which absorb at least one quantum in a temporal period T, whose range includes the time interval 600 musec less than or equal T less than or equal 30 sec. This generalization obtains over the entire scotopic energy range (congruent to 3 log units) where rod dark adaptations has been studied. 4. Thus, the state of "bleaching' adaptation is determined by some by-product of the normal chain of events in scotopic excitation. About this by-product three important deductions are made: (i) its production is a monotonic function of the initial effective quantum absorptions; (ii) its production occurs before the metarhodopsin I leads to to metarhodopsin II dark reaction; (iii) it cannot be any photoproduct of the rhodopsin cycle. PMID:1151791

  18. Oxidative Stress and Hepatic Stellate Cells: A PARADOXICAL RELATIONSHIP.

    PubMed

    Gandhi, Chandrashekhar R

    2012-01-01

    In physiology, reactive oxygen species (ROS) are produced by most cells for normal function and as a defense mechanism against foreign particles, microbes and viruses. Hepatic macrophages (Kupffer cells), sinusoidal endothelial cells, hepatocytes and hepatic stellate cells (HSCs) are all capable of generating ROS in physiology and pathology. ROS are also produced by infiltrating inflammatory cells during acute and chronic liver injury. Increased levels of ROS have been implicated in apoptotic/necrotic death of hepatocytes, and liver failure. In contrast to causing injury to hepatocytes, ROS and lipid peroxidation products induce transdifferentiation of the quiescent HSCs into an activated highly proliferative myofibroblast-like phenotype. ROS and lipid peroxidation products also stimulate the synthesis of extracellular matrix (ECM) by activated HSCs. Deposition of excessive amounts of ECM is the primary mechanism of fibrosis and cirrhosis of the liver, and interactions between ROS and HSCs appear to play a major role in this pathology. Although these findings suggest that HSCs are resistant to the injurious actions of ROS, there is compelling evidence demonstrating ROS-induced death of activated HSCs. Detailed mechanistic understanding of such paradoxical interactions between ROS and HSCs will be critical for developing therapies for chronic fibrotic liver disease.

  19. Acetylcholine-Atropine Interactions: Paradoxical Effects on Atrial Fibrillation Inducibility.

    PubMed

    Liu, Yu; Scherlag, Benjamin J; Fan, Youqi; Xia, Wenfang; Huang, He; Po, Sunny S

    2017-03-21

    Atropine (ATr) is well known as a cholinergic antagonist, however, at low concentrations ATr could paradoxically accentuate the parasympathetic actions of acetylcholine (ACh). In 22 pentobarbital anesthetized dogs, via a left and right thoracotomy, a leak proof barrier was attached to isolate the atrial appendages (AAs) from the rest of the atria. In Group 1(Ach+ATr+Ach), ACh, 100 mM, was placed on the AA followed by the application of ATr, 2mg/cc. The average AFdur was 17±7 minutes. After ATr was applied to the AA and ACh again tested, the AFdur was markedly attenuated (2±2 minutes, p<0.05). In Group 2 (ATr+Ach), ATr was initially applied to the AA followed by the application of ACh, 100 mM. There was no significant difference in AF duration (16±4 minutes vs 18±2 minutes, p=NS). The inhibitory effect of ATr on induced HR reduction (electrical stimulation of the anterior right ganglionated plexi and vagal nerves) was no difference between Groups 1 and 2. These observations suggest that when ATr is initially administered it attaches to the allosteric site of the muscarinic ACh receptor (M2 AChRs) leaving the orthosteric site free to be occupied by ACh. The M3 receptor that controls HR slowing does not show the same allosteric properties.

  20. The Fermi paradox: An approach based on percolation theory

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.

    1993-01-01

    If even a very small fraction of the hundred billion stars in the galaxy are home to technological civilizations which colonize over interstellar distances, the entire galaxy could be completely colonized in a few million years. The absence of such extraterrestrial civilizations visiting Earth is the Fermi paradox. A model for interstellar colonization is proposed using the assumption that there is a maximum distance over which direct interstellar colonization is feasible. Due to the time lag involved in interstellar communications, it is assumed that an interstellar colony will rapidly develop a culture independent of the civilization that originally settled it. Any given colony will have a probability P of developing a colonizing civilization, and a probability (1-P) that it will develop a non-colonizing civilization. These assumptions lead to the colonization of the galaxy occuring as a percolation problem. In a percolation problem, there will be a critical value of percolation probability, P(sub c). For P less than P(sub c), colonization will always terminate after a finite number of colonies. Growth will occur in 'clusters', with the outside of each cluster consisting of non-colonizing civilizations. For P greater than P(sub c), small uncolonized voids will exist, bounded by non-colonizing civilizations. For P approximately = to P(sub c), arbitrarily large filled regions exist, and also arbitrarily large empty regions.

  1. Emotion and false memory: The context-content paradox.

    PubMed

    Bookbinder, S H; Brainerd, C J

    2016-12-01

    False memories are influenced by a variety of factors, but emotion is a variable of special significance, for theoretical and practical reasons. Interestingly, emotion's effects on false memory depend on whether it is embedded in the content of to-be-remembered events or in our moods, where mood is an aspect of the context in which events are encoded. We sketch the theoretical basis for this content-context dissociation and then review accumulated evidence that content and context effects are indeed different. Paradoxically, we find that in experiments on spontaneous and implanted false memories, negatively valenced content foments distortion, but negatively valenced moods protect against it. In addition, correlational data show that enduring negative natural moods (e.g., depression) foment false memory. Current opponent-process models of false memory, such as fuzzy-trace theory, are able to explain the content-context dissociation: Variations in emotional content primarily affect memory for the gist of events, whereas variations in emotional context primarily affect memory for events' exact verbatim form. Important questions remain about how these effects are modulated by variations in memory tests and in arousal. Promising methods of tackling those questions are outlined, especially designs that separate the gist and verbatim influences of emotion. (PsycINFO Database Record

  2. Democratic parenting: paradoxical messages in democratic parent education theories

    NASA Astrophysics Data System (ADS)

    Oryan, Shlomit; Gastil, John

    2013-06-01

    Some prominent parent education theories in the United States and other Western countries base their educational viewpoint explicitly on democratic values, such as mutual respect, equality and personal freedom. These democratic parenting theories advocate sharing power with children and including them in family decision making. This study presents a textual analysis of two such theories, the Adlerian model of parent education and the Parent Effectiveness Training (PET) model, as they are embodied in two original bestselling textbooks. Through content and argumentation analysis of these influential texts, this study examines the paradoxes inherent in these two theories when they articulate how to implement fully democratic principles within the parent-child relationship. We discover that in spite of their democratic rationale, both books offer communication practices that guide the child to modify misbehaviour, enforce parental power, and manipulate the child to make decisions that follow parental judgment, and thus do not endorse the use of a truly democratic parenting style. We suggest, as an alternative to the democratic parenting style, that parents be introduced to a guardianship management style, in which they do not share authority with children, but seek opportunities for enabling children to make more autonomous decisions and participate in more family decision making.

  3. Poverty, obesity, and malnutrition: an international perspective recognizing the paradox.

    PubMed

    Tanumihardjo, Sherry A; Anderson, Cheryl; Kaufer-Horwitz, Martha; Bode, Lars; Emenaker, Nancy J; Haqq, Andrea M; Satia, Jessie A; Silver, Heidi J; Stadler, Diane D

    2007-11-01

    In the year 2000, multiple global health agencies and stakeholders convened and established eight tenets that, if followed, would make our world a vastly better place. These tenets are called the Millennium Development Goals. Most of these goals are either directly or indirectly related to nutrition. The United Nations has led an evaluation team to monitor and assess the progress toward achieving these goals until 2015. We are midway between when the goals were set and the year 2015. The first goal is to "eradicate extreme poverty and hunger." Our greatest responsibility as nutrition professionals is to understand the ramifications of poverty, chronic hunger, and food insecurity. Food insecurity is complex, and the paradox is that not only can it lead to undernutrition and recurring hunger, but also to overnutrition, which can lead to overweight and obesity. It is estimated that by the year 2015 noncommunicable diseases associated with overnutrition will surpass undernutrition as the leading causes of death in low-income communities. Therefore, we need to take heed of the double burden of malnutrition caused by poverty, hunger, and food insecurity. Informing current practitioners, educators, and policymakers and passing this information on to future generations of nutrition students is of paramount importance.

  4. Exploring the CK2 Paradox: Restless, Dangerous, Dispensable

    PubMed Central

    Franchin, Cinzia; Borgo, Christian; Zaramella, Silvia; Cesaro, Luca; Arrigoni, Giorgio; Salvi, Mauro; Pinna, Lorenzo A.

    2017-01-01

    The history of protein kinase CK2 is crowded with paradoxes and unanticipated findings. Named after a protein (casein) that is not among its physiological substrates, CK2 remained in search of its targets for more than two decades after its discovery in 1954, but it later came to be one of the most pleiotropic protein kinases. Being active in the absence of phosphorylation and/or specific stimuli, it looks unsuitable to participate in signaling cascades, but its “lateral” implication in a variety of signaling pathways is now soundly documented. At variance with many “onco-kinases”, CK2 is constitutively active, and no oncogenic CK2 mutant is known; still high CK2 activity correlates to neoplasia. Its pleiotropy and essential role may cast doubts on the actual “druggability” of CK2; however, a CK2 inhibitor is now in Phase II clinical trials for the treatment of cancer, and cell clones viable in the absence of CK2 are providing information about the mechanism by which cancer becomes addicted to high CK2 levels. A phosphoproteomics analysis of these CK2 null cells suggests that CK2 pleiotropy may be less pronounced than expected and supports the idea that the phosphoproteome generated by this kinase is flexible and not rigidly pre-determined. PMID:28117670

  5. From Planck Constant to Isomorphicity Through Justice Paradox

    NASA Astrophysics Data System (ADS)

    Hidajatullah-Maksoed, Widastra

    2015-05-01

    Robert E. Scott in his ``Chaos theory and the Justice Paradox'', William & Mary Law Review, v 35, I 1, 329 (1993) wrotes''...As we approach the 21-st Century, the signs of social disarray are everywhere. Social critics observe the breakdown of core structure - the nuclear family, schools, neighborhoods & political groups''. For completions for ``soliton'' first coined by Morikazu TODA, comparing the ``Soliton on Scott-Russell aqueduct on the Union Canal near Heriot-WATT University, July 12, 1995 to Michael Stock works: ``a Fine WATT-Balance: Determination of Planck constant & Redefinition of Kilogram'', January 2011, we can concludes the inherencies between `chaos' & `soliton'. Further through ``string theory'' from Michio KAKU sought statements from Peter Mayr: Stringy world brane & Exponential hierarchy'', JHEP 11 (2000): ``if the 5-brane is embedded in flat 10-D space time, the 6-D Planck mass on the brane is infinite'' who also describes the relation of isomorphicity & ``string theory'', from whom denotes the smart city. Replace this text with your abstract body. Incredible acknowledgments to HE. Mr. Drs. P. SWANTORO & HE. Mr. Dr-HC Jakob OETAMA.

  6. A Case of Risperidone Induced Stuttering as a Paradox

    PubMed Central

    ATAY, İnci Meltem; TANRITANIR, Bilal; AKPINAR, Abdullah; DEMİRDAŞ, Arif

    2014-01-01

    The main feature of stuttering is the disturbance in terms of both timing and fluency of speech inappropriate with the age. This disturbance is characterized with the repetition and prolongation of sounds and syllables. There are two types of stuttering as acquired and developmental. Acquired stuttering may begin suddenly at any age and may be seen rarely due to the adverse effects of drugs. Stuttering induced by antipsychotics may develop very rarely. Risperidone is a strong antagonist of dopamin 2 (D2) and serotonin 2A (5 HT2A) and shows a high affinity for α1 and α2 noradrenaline receptors. It’s used in a wide spectrum including psychotic disorders, mood disorders, and behavioral disorders, even for the treatment of stuttering. Risperidone treats the symptoms of stuttering by the antagonism of D2 receptors with an increase in striatal metabolism. In literature, we haven’t observed any other case reports except the two stuttering cases with psychotic disorders due to the short term and high-dose risperidone treatment. In our case, stuttering adverse effect of chronic low-dose risperidone treatment is remarkable that is discussed for the first time. As well as the use of risperidone for the treatment of stuttering, stuttering adverse effect seems to be interesting as a paradox.

  7. Geology of the Paradox quadrangle, Montrose county, Colorado

    USGS Publications Warehouse

    Withington, C.F.

    1954-01-01

    The Paradox quadrangle is one of eighteen 7 1/2-minute quadrangles covering the principal carnotite-producing area of southwestern Colorado. The geology of these quadrangles was mapped by the U.S. Geological Survey for the Atomic Energy Commission as part of a comprehensive study of carnotite deposits. The rocks exposed in the eighteen quadrangles consist of crystalline rocks of pre-Cambrian age and sedimentary rocks that range in age from late Paleozoic to Quaternary. Over much of the area the sedimentary rocks are flat lying, but in places the rocks are disrupted by high-angle faults, and northwest-trending folds. Conspicuous among the folds are large anticlines having cores of intrusive salt and gypsum. Most of the carnotite deposits are confined to the Salt Wash sandstone member of the Jurassic Morrison formation, Within this sandstone, most of the deposits are spottily distributed through an arcuate zone known as the "Uravan Mineral Belt". Individual deposits range in size from irregular masses containing only a few tons of ore to large, tabular masses containing thousands of tons. The ore consists largely of sandstone selectively impregnated and in part replaced by uranium and vanadium minerals. Most of the deposits appear to be related to certain sedimentary structures in sandstones of favorable composition.

  8. Exploring the CK2 Paradox: Restless, Dangerous, Dispensable.

    PubMed

    Franchin, Cinzia; Borgo, Christian; Zaramella, Silvia; Cesaro, Luca; Arrigoni, Giorgio; Salvi, Mauro; Pinna, Lorenzo A

    2017-01-20

    The history of protein kinase CK2 is crowded with paradoxes and unanticipated findings. Named after a protein (casein) that is not among its physiological substrates, CK2 remained in search of its targets for more than two decades after its discovery in 1954, but it later came to be one of the most pleiotropic protein kinases. Being active in the absence of phosphorylation and/or specific stimuli, it looks unsuitable to participate in signaling cascades, but its "lateral" implication in a variety of signaling pathways is now soundly documented. At variance with many "onco-kinases", CK2 is constitutively active, and no oncogenic CK2 mutant is known; still high CK2 activity correlates to neoplasia. Its pleiotropy and essential role may cast doubts on the actual "druggability" of CK2; however, a CK2 inhibitor is now in Phase II clinical trials for the treatment of cancer, and cell clones viable in the absence of CK2 are providing information about the mechanism by which cancer becomes addicted to high CK2 levels. A phosphoproteomics analysis of these CK2 null cells suggests that CK2 pleiotropy may be less pronounced than expected and supports the idea that the phosphoproteome generated by this kinase is flexible and not rigidly pre-determined.

  9. Photon uncertainty solves the Einstein-Podolsky-Rosen paradox

    NASA Astrophysics Data System (ADS)

    Tommasini, D.

    2003-05-01

    Einstein, Podolsky, and Rosen pointed out that the quantum-mechanical description of “physical reality” implies an unphysical, instantaneous action between distant measurements. To avoid such an action at a distance, these three concluded that quantum mechanics had to be incomplete. However, its extensions involving additional “hidden variables,” allowing for the recovery of determinism and locality, have been disproved experimentally (Bell’s theorem). In this paper, an opposite solution of the paradox is presented, based on the greater indeterminism of the modern quantum field theory (QFT) description of particle physics, which prevents the preparation of any state having a definite number of particles. The resulting uncertainty in photon radiation has interesting consequences in quantum information theory (e.g., cryptography and teleportation). Moreover, since it allows for fewer elements of Einstein-Podolsky-Rosen (EPR) physical reality than the old non-relativistic quantum mechanics, QFT satisfies the EPR condition of completeness without the need for hidden variables. The residual physical reality never violates locality; thus, the unique objective proof of “quantum nonlocality” is removed in an interpretation-independent way. At the same time, the supposed nonlocality of the EPR correlations turns out to be a problem in interpretation of the measurement process. If we do not rely on hidden variables or new physics beyond QFT, the viable interpretation is a minimal statistical one, which preserves locality and Lorentz symmetry.

  10. Massive higher spins from BRST and tractors

    NASA Astrophysics Data System (ADS)

    Grigoriev, Maxim; Waldron, Andrew

    2011-12-01

    We obtain the higher spin tractor equations of motion conjectured by Gover et al. from a BRST approach and use those methods to prove that they describe massive, partially massless and massless higher spins in conformally flat backgrounds. The tractor description makes invariance under local choices of unit systems manifest. In this approach, physical models are described by conformal, rather than (pseudo-)Riemannian geometry. In particular masses become geometric quantities, namely the weights of tractor fields. Massive models can therefore be handled in a unified and simple manner mimicking the gauge principle usually employed for massless models. From a holographic viewpoint, these models describe both the bulk and boundary theories in terms of conformal geometry. This is an important advance, because tying the boundary conformal structure to that of the bulk theory gives greater control over a bulk-boundary correspondence.

  11. Massive ovarian edema, due to adjacent appendicitis.

    PubMed

    Callen, Andrew L; Illangasekare, Tushani; Poder, Liina

    2017-04-01

    Massive ovarian edema is a benign clinical entity, the imaging findings of which can mimic an adnexal mass or ovarian torsion. In the setting of acute abdominal pain, identifying massive ovarian edema is a key in avoiding potential fertility-threatening surgery in young women. In addition, it is important to consider other contributing pathology when ovarian edema is secondary to another process. We present a case of a young woman presenting with subacute abdominal pain, whose initial workup revealed marked enlarged right ovary. Further imaging, diagnostic tests, and eventually diagnostic laparoscopy revealed that the ovarian enlargement was secondary to subacute appendicitis, rather than a primary adnexal process. We review the classic ultrasound and MRI imaging findings and pitfalls that relate to this diagnosis.

  12. Superdense massive galaxies in the nearby universe

    NASA Astrophysics Data System (ADS)

    Ferré-Mateu, Anna; Trujillo, Ignacio

    2010-04-01

    At high-z the most superdense massive galaxies are supposed to be the result of gas-rich mergers resulting in compact remnant (Khochfar & Silk (2006); Naab et al. (2007)). After this, dry mergers are expected to be the mechanism that moves these very massive galaxies towards the current stellar mass size relation. Whitin these merging scenarios, a non-negligible fraction (1-10%) of these galaxies is expected to survive since that epoch retaining their compactness and presenting old stellar populations in the past universe.Using the NYU Value-Added Galaxy Catalog (DR6), we find only a tiny fraction of galaxies (~0.03%) with re ≤ 1.5 kpc and M* ≥ 8x1010M⊙ in the local Universe (z~0.2). Surprisingly, they are relatively young (~2Gyr) and metal rich ([Z/H]~0.2) These results have been published in Trujillo et al. (2009)

  13. Visser's massive graviton bimetric theory revisited

    SciTech Connect

    Roany, Alain de; Chauvineau, Bertrand; Freitas Pacheco, Jose A. de

    2011-10-15

    A massive gravity theory was proposed by Visser in the late 1990s. This theory, based on a background metric b{sub {alpha}{beta}} and on an usual dynamical metric g{sub {alpha}{beta}} has the advantage of being free of ghosts as well as discontinuities present in other massive theories proposed in the past. In the present investigation, the equations of Visser's theory are revisited with particular care on the related conservation laws. It will be shown that a multiplicative factor is missing in the graviton tensor originally derived by Visser, which has no incidence on the weak field approach but becomes important in the strong field regime when, for instance, cosmological applications are considered. In this case, contrary to some previous claims found in the literature, we conclude that a nonstatic background metric is required in order to obtain a solution able to mimic the {Lambda}CDM cosmology.

  14. Stable FLRW solutions in generalized massive gravity

    NASA Astrophysics Data System (ADS)

    de Rham, Claudia; Fasiello, Matteo; Tolley, Andrew J.

    2014-12-01

    We present exact Friedmann Lemaítre Robertson Walkers (FLRW) solutions in generalized massive gravity where the mass parameters are naturally promoted to Lorentz-invariant functions of the Stückelberg fields. This new dependence relaxes the constraint that would otherwise prevent massive gravity from possessing exact FLRW solutions. It does so without the need to introduce additional degrees of freedom. We find self-accelerating cosmological solutions and show that, with a mild restriction on the region of phase space, these cosmological solutions exhibit full stability, i.e. absence of ghosts and gradient instabilities for all the tensor, vector and scalar modes, for all cosmic time. We perform the full decoupling limit analysis, including vector degrees of freedom, which can be used to confirm the existence of an active Vainshtein mechanism about these solutions.

  15. Parallel rendering techniques for massively parallel visualization

    SciTech Connect

    Hansen, C.; Krogh, M.; Painter, J.

    1995-07-01

    As the resolution of simulation models increases, scientific visualization algorithms which take advantage of the large memory. and parallelism of Massively Parallel Processors (MPPs) are becoming increasingly important. For large applications rendering on the MPP tends to be preferable to rendering on a graphics workstation due to the MPP`s abundant resources: memory, disk, and numerous processors. The challenge becomes developing algorithms that can exploit these resources while minimizing overhead, typically communication costs. This paper will describe recent efforts in parallel rendering for polygonal primitives as well as parallel volumetric techniques. This paper presents rendering algorithms, developed for massively parallel processors (MPPs), for polygonal, spheres, and volumetric data. The polygon algorithm uses a data parallel approach whereas the sphere and volume render use a MIMD approach. Implementations for these algorithms are presented for the Thinking Ma.chines Corporation CM-5 MPP.

  16. How Massive Single Stars End Their Life

    NASA Technical Reports Server (NTRS)

    Heger, A.; Fryer, C. L.; Woosley, S. E.; Langer, N.; Hartmann, D. H.

    2003-01-01

    How massive stars die-what sort of explosion and remnant each produces-depends chiefly on the masses of their helium cores and hydrogen envelopes at death. For single stars, stellar winds are the only means of mass loss, and these are a function of the metallicity of the star. We discuss how metallicity, and a simplified prescription for its effect on mass loss, affects the evolution and final fate of massive stars. We map, as a function of mass and metallicity, where black holes and neutron stars are likely to form and where different types of supernovae are produced. Integrating over an initial mass function, we derive the relative populations as a function of metallicity. Provided that single stars rotate rapidly enough at death, we speculate on stellar populations that might produce gamma-ray bursts and jet-driven supernovae.

  17. Massively Parallel Computing: A Sandia Perspective

    SciTech Connect

    Dosanjh, Sudip S.; Greenberg, David S.; Hendrickson, Bruce; Heroux, Michael A.; Plimpton, Steve J.; Tomkins, James L.; Womble, David E.

    1999-05-06

    The computing power available to scientists and engineers has increased dramatically in the past decade, due in part to progress in making massively parallel computing practical and available. The expectation for these machines has been great. The reality is that progress has been slower than expected. Nevertheless, massively parallel computing is beginning to realize its potential for enabling significant break-throughs in science and engineering. This paper provides a perspective on the state of the field, colored by the authors' experiences using large scale parallel machines at Sandia National Laboratories. We address trends in hardware, system software and algorithms, and we also offer our view of the forces shaping the parallel computing industry.

  18. THE STELLAR HALOS OF MASSIVE ELLIPTICAL GALAXIES

    SciTech Connect

    Greene, Jenny E.; Murphy, Jeremy D.; Comerford, Julia M.; Gebhardt, Karl; Adams, Joshua J.

    2012-05-01

    We use the Mitchell Spectrograph (formerly VIRUS-P) on the McDonald Observatory 2.7 m Harlan J. Smith Telescope to search for the chemical signatures of massive elliptical galaxy assembly. The Mitchell Spectrograph is an integral-field spectrograph with a uniquely wide field of view (107'' Multiplication-Sign 107''), allowing us to achieve remarkably high signal-to-noise ratios of {approx}20-70 pixel{sup -1} in radial bins of 2-2.5 times the effective radii of the eight galaxies in our sample. Focusing on a sample of massive elliptical galaxies with stellar velocity dispersions {sigma}{sub *} > 150 km s{sup -1}, we study the radial dependence in the equivalent widths (EW) of key metal absorption lines. By twice the effective radius, the Mgb EWs have dropped by {approx}50%, and only a weak correlation between {sigma}{sub *} and Mgb EW remains. The Mgb EWs at large radii are comparable to those seen in the centers of elliptical galaxies that are {approx} an order of magnitude less massive. We find that the well-known metallicity gradients often observed within an effective radius continue smoothly to 2.5 R{sub e} , while the abundance ratio gradients remain flat. Much like the halo of the Milky Way, the stellar halos of our galaxies have low metallicities and high {alpha}-abundance ratios, as expected for very old stars formed in small stellar systems. Our observations support a picture in which the outer parts of massive elliptical galaxies are built by the accretion of much smaller systems whose star formation history was truncated at early times.

  19. Massive Multi-Agent Systems Control

    NASA Technical Reports Server (NTRS)

    Campagne, Jean-Charles; Gardon, Alain; Collomb, Etienne; Nishida, Toyoaki

    2004-01-01

    In order to build massive multi-agent systems, considered as complex and dynamic systems, one needs a method to analyze and control the system. We suggest an approach using morphology to represent and control the state of large organizations composed of a great number of light software agents. Morphology is understood as representing the state of the multi-agent system as shapes in an abstract geometrical space, this notion is close to the notion of phase space in physics.

  20. Are All Magnetic White Dwarf Stars Massive?

    NASA Astrophysics Data System (ADS)

    Nitta, A.; Kepler, S. O.; Kulebi, B.; Koester, D.; Kleinman, S. J.; Winget, D. E.; Castanheira, B. G.; Corsico, A. H.

    2017-03-01

    We obtained follow-up spectra on 25 white dwarf stars identified in our white dwarf catalog of Sloan Digital Sky Survey (SDSS) as massive or magnetic. We identified over 300 magnetic white dwarf stars from SDSS with some uncertainties due to the low S/N of the spectra. With much higher S/N Gemini data, our sample should be able to help us confirm accuracy of our determinations. We present here our results so far from the follow up observations.