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Sample records for sodium-water reaction phenomenon

  1. Theoretical Study of Sodium-Water Surface Reaction Mechanism

    NASA Astrophysics Data System (ADS)

    Kikuchi, Shin; Kurihara, Akikazu; Ohshima, Hiroyuki; Hashimoto, Kenro

    Computational study of the sodium-water reaction at the gas (water) - liquid (sodium) interface has been carried out using the ab initio (first-principle) method. A possible reaction channel has been identified for the stepwise OH bond dissociations of a single water molecule. The energetics including the binding energy of a water molecule on the sodium surface, the activation energies of the bond cleavages, and the reaction energies, have been evaluated, and the rate constants of the first and second OH bond-breakings have been compared. It was found that the estimated rate constant of the former was much larger than the latter. The results are the basis for constructing the chemical reaction model used in a multi-dimensional sodium-water reaction code, SERAPHIM, being developed by Japan Atomic Energy Agency (JAEA) toward the safety assessment of the steam generator (SG) in a sodium-cooled fast reactor (SFR).

  2. Microstructure and deformation mode of a stainless steel rupture disc exposed to sodium-water reaction

    SciTech Connect

    Sudha, C.; Parameswaran, P. Kishore, S.; Murthy, C. Meikanda; Rajan, M.; Vijayalakshmi, M.; Raghunathan, V.S.

    2008-08-15

    This paper deals with microstructural studies carried out on an austenitic stainless steel rupture disc which was exposed to sodium-water reaction. The rupture disc was part of a leak simulator put in a micro leak test section which was used to study the 'self wastage' of steam generator tubes. During micro leak testing, the rupture disc failed exhibiting a linear crack at a much lower pressure of 10 MPa rather than bursting open at the higher designed pressure of 15 MPa. The failed rupture disc revealed different microstructural features on the inner (steam exposed) and outer (sodium exposed) surfaces. Using microstructure as the signature, the temperature experienced by the rupture disc was predicted as {>=} 1273 K. Evidence for the exposure of the rupture disc to highly exothermic sodium-water reaction was obtained in the form of sodium rich debris, microcracks and deformation bands. Detailed transmission electron microscopy revealed the nature of deformation bands as deformation twins which is not a preferred failure mode for austenitic stainless steels.

  3. Development of a multiphysics analysis system for sodium-water reaction phenomena in steam generators of sodium-cooled fast reactors

    SciTech Connect

    Uchibori, Akihiro; Kurihara, Akikazu; Ohshima, Hiroyuki

    2015-12-31

    A multiphysics analysis system for sodium-water reaction phenomena in a steam generator of sodium-cooled fast reactors was newly developed. The analysis system consists of the mechanistic numerical analysis codes, SERAPHIM, TACT, and RELAP5. The SERAPHIM code calculates the multicomponent multiphase flow and sodium-water chemical reaction caused by discharging of pressurized water vapor. Applicability of the SERAPHIM code was confirmed through the analyses of the experiment on water vapor discharging in liquid sodium. The TACT code was developed to calculate heat transfer from the reacting jet to the adjacent tube and to predict the tube failure occurrence. The numerical models integrated into the TACT code were verified through some related experiments. The RELAP5 code evaluates thermal hydraulic behavior of water inside the tube. The original heat transfer correlations were corrected for the tube rapidly heated by the reacting jet. The developed system enables evaluation of the wastage environment and the possibility of the failure propagation.

  4. Development of a multiphysics analysis system for sodium-water reaction phenomena in steam generators of sodium-cooled fast reactors

    NASA Astrophysics Data System (ADS)

    Uchibori, Akihiro; Kurihara, Akikazu; Ohshima, Hiroyuki

    2015-12-01

    A multiphysics analysis system for sodium-water reaction phenomena in a steam generator of sodium-cooled fast reactors was newly developed. The analysis system consists of the mechanistic numerical analysis codes, SERAPHIM, TACT, and RELAP5. The SERAPHIM code calculates the multicomponent multiphase flow and sodium-water chemical reaction caused by discharging of pressurized water vapor. Applicability of the SERAPHIM code was confirmed through the analyses of the experiment on water vapor discharging in liquid sodium. The TACT code was developed to calculate heat transfer from the reacting jet to the adjacent tube and to predict the tube failure occurrence. The numerical models integrated into the TACT code were verified through some related experiments. The RELAP5 code evaluates thermal hydraulic behavior of water inside the tube. The original heat transfer correlations were corrected for the tube rapidly heated by the reacting jet. The developed system enables evaluation of the wastage environment and the possibility of the failure propagation.

  5. Analysis of large-leak test SWAT-3 Run-6 data by use of sodium-water-reaction analysis code SWAAM-I

    SciTech Connect

    Shin, Y.W.; Lin, H.C.

    1982-02-01

    The Sodium Water Advanced Analysis Method computer code (SWAAM-I) is used to analyze the large-leak test data SWAT-3 Run-6. The SWAT-3 is the mockup of the secondary system of the Japanese breeder-reactor demonstration plant Monju. The steam-generator design for the Monju reactor was a helical-coil-tube type with a cover-gas space, and the SWAT-3 Run-6 Test vessel simulates this design of the steam generator. The objectives of this work are: (1) to examine the adequacy of the SWAAM-I code for the helical-coil-tube steam-generator system, (2) to understand and confirm the understanding of phenomena that have major design implications, and (3) to define needs for additional development of SWAAM-I code capabilities.

  6. Reaction Current Phenomenon in Bifunctional Catalytic Metal-Semiconductor Nanostructures

    NASA Astrophysics Data System (ADS)

    Hashemian, Mohammad Amin

    Energy transfer processes accompany every elementary step of catalytic chemical processes on material surface including molecular adsorption and dissociation on atoms, interactions between intermediates, and desorption of reaction products from the catalyst surface. Therefore, detailed understanding of these processes on the molecular level is of great fundamental and practical interest in energy-related applications of nanomaterials. Two main mechanisms of energy transfer from adsorbed particles to a surface are known: (i) adiabatic via excitation of quantized lattice vibrations (phonons) and (ii) non-adiabatic via electronic excitations (electron/hole pairs). Electronic excitations play a key role in nanocatalysis, and it was recently shown that they can be efficiently detected and studied using Schottky-type catalytic nanostructures in the form of measureable electrical currents (chemicurrents) in an external electrical circuit. These nanostructures typically contain an electrically continuous nanocathode layers made of a catalytic metal deposited on a semiconductor substrate. The goal of this research is to study the direct observations of hot electron currents (chemicurrents) in catalytic Schottky structures, using a continuous mesh-like Pt nanofilm grown onto a mesoporous TiO2 substrate. Such devices showed qualitatively different and more diverse signal properties, compared to the earlier devices using smooth substrates, which could only be explained on the basis of bifunctionality. In particular, it was necessary to suggest that different stages of the reaction are occurring on both phases of the catalytic structure. Analysis of the signal behavior also led to discovery of a formerly unknown (very slow) mode of the oxyhydrogen reaction on the Pt/TiO2(por) system occurring at room temperature. This slow mode was producing surprisingly large stationary chemicurrents in the range 10--50 microA/cm2. Results of the chemicurrent measurements for the bifunctional

  7. Medical Students' Reactions to Anatomic Dissection and the Phenomenon of Cadaver Naming

    ERIC Educational Resources Information Center

    Williams, Austin D.; Greenwald, Emily E.; Soricelli, Rhonda L.; DePace, Dennis M.

    2014-01-01

    The teaching of gross anatomy has, for centuries, relied on the dissection of human cadavers, and this formative experience is known to evoke strong emotional responses. The authors hypothesized that the phenomenon of cadaver naming is a coping mechanism used by medical students and that it correlates with other attitudes about dissection and body…

  8. Medical students' reactions to anatomic dissection and the phenomenon of cadaver naming.

    PubMed

    Williams, Austin D; Greenwald, Emily E; Soricelli, Rhonda L; DePace, Dennis M

    2014-01-01

    The teaching of gross anatomy has, for centuries, relied on the dissection of human cadavers, and this formative experience is known to evoke strong emotional responses. The authors hypothesized that the phenomenon of cadaver naming is a coping mechanism used by medical students and that it correlates with other attitudes about dissection and body donation. The authors developed a 33-question electronic survey to which 1,156 medical students at 12 medical schools in the United States voluntarily responded (November 2011-March 2012). They also surveyed course directors from each institution regarding their curricula and their observations of students' coping mechanisms. The majority of students (574, 67.8%) named their cadaver. Students most commonly cited the cadaver's age as the reason they chose a particular name for the cadaver. A minority of the students who did not name the cadaver reported finding the practice of naming disrespectful. Almost all students indicated that they would have liked to know more about their donor, particularly his or her medical history. Finally, students who knew the birth name of the donor used it less frequently than predicted. The authors found that the practice of naming cadavers is extremely prevalent among medical students and that inventive naming serves as a beneficial coping mechanism. The authors suggest that developing a method of providing students with more information about their cadaver while protecting the anonymity of the donor and family would be useful.

  9. Power plant II - Sodium-water

    NASA Astrophysics Data System (ADS)

    Roche, M.

    The implementation of a sodium based heat exchange loop is presented as a means of reducing the required size of a solar thermal power plant heat exchanger. Sodium as a heat transfer fluid allows operations near 535 C with electromagnetic pumps. It is noted that sodium must be completely sealed in and surrounded with a neutral gas such as nitrogen or argon. The higher temperatures pave the way for a more efficient thermodynamic cycle, although the Themis receiver would necessarily need a faster loop in addition to more absorbent surfaces to adequately handle the sodium liquid. The steam lines would be helically wound in a chamber through which the sodium flows linearly downward. Storage is concluded to not be feasible under current technology due to the violent reactions possible between sodium and water or hitec salts. An auxiliary heat source would be required.

  10. [Raynaud's phenomenon].

    PubMed

    Piérard-Franchimont, C; Piérard, G E; Hermanns-Lê, T

    2012-12-01

    Raynaud's phenomenon is a vascular acrosyndrome caused by a variety of diseases. There is a distinction between the idiopathic Raynaud's disease, the secondary types and the suspicious idiopathic Raynaud's phenomenon.

  11. Aminoglycosides modify the in vitro metachromatic reaction and murine generalized Shwartzman phenomenon induced by Salmonella minnesota R595 lipopolysaccharide.

    PubMed Central

    Focà, A; Matera, G; Iannello, D; Berlinghieri, M C; Liberto, M C

    1991-01-01

    Endotoxin-neutralizing activity may be an important property for antibiotics to be used in severe sepsis. Several antibiotics, belonging to different classes, were evaluated as to their endotoxin-neutralizing ability, using the inhibition of an in vitro metachromatic assay for lipopolysaccharides and a murine generalized Shwartzman reaction model. Gentamicin, amikacin, and sisomicin have been found to share significant in vitro antiendotoxin activity at an antibiotic/endotoxin ratio as low as 1.0/5 (by weight) and to reduce the murine generalized Shwartzman reaction at an antibiotic/endotoxin ratio of 3.3/5. Images PMID:1759842

  12. [Raynaud's phenomenon].

    PubMed

    Saavedra Salinas, Miguel Ángel; Carrillo Vázquez, Sandra Miriam

    2006-11-01

    Raynaud's phenomenon is characterized by repeated daily attacks of ischemia followed by reperfusion at the acrallevel. It is a frequent syndrome found in medical practice; and it can be considered as primary or secondary to other conditions, including rheumatic autoimmune diseases. Current classification had clinical and therapeutic implications. Careful clinical evaluation is the most reliable and reproducible method in the diagnosis of Raynaud's phenomenon. Several risk factors had been associated in the genesis of Raynaud's phenomenon; however, its pathogenesis remains elusive although recently, considerable progress in disease mechanism had been described. Such advances are directing new lines of therapy.

  13. Raynaud's Phenomenon

    MedlinePlus

    ... form. It is common for patients with a connective tissue disease to have Raynaud’s phenomenon. It occurs in ... enlarged or malformed, the patient may have a connective tissue disease. Antinuclear antibody (ANA) test. In this blood ...

  14. A preliminary study on numerical simulation of microwave heating process for chemical reaction and discussion of hotspot and thermal runaway phenomenon

    NASA Astrophysics Data System (ADS)

    Zhao, Xiang; Huang, Kama; Yan, Liping; Yao, Yuan

    2009-04-01

    The nonlinear process of microwave heating chemical reaction is studied by means of numerical simulation. Especially, the variation of temperature in terms of space and time, as well as the hotspot and thermal runaway phenomena are discussed. Suppose the heated object is a cylinder and the incident electromagnetic (EM) wave is plane wave, the problem turns out to be a coupling calculation of 2D multi-physical fields. The integral equation of EM field is solved using the method of moment (MoM) and the thermal conduction equation is solved using a semi-analysis method. Moreover, a method to determine the equivalent complex permittivity of reactant under the heating is presented in order to perform the calculation. The numerical results for water and a dummy chemical reaction ( A) show that the hotspot is a ubiquitous phenomenon in microwave heating process. When the radius of the heated object is small, the highest temperature occurs somewhere inside the object due to the concentration of the EM wave. While the radius increases to a certain degree, the highest temperature occurs somewhere close to the surface due to the skin effect, and the whole high temperature area shows crescent-shaped. That is in accordance with basic physical principles. If the radius is kept the same in the heating process, the hotspot position of water does not change, while that of reaction A with several radius values varies. For either water or A, the thermal runaway phenomenon in which small difference of radius results in large difference of highest temperature, occurs easily when the radius is small. On the contrary, it is not evident when the radius is large. Moreover, it is notable that the highest temperature in water shows oscillating decreasing trend with the increase of radius, but in reaction A almost decreases monotonously. Further study should be performed to determine if this difference is only an occasional occurrence.

  15. THE ACUTE INFLAMMATORY REACTION IN THE RABBIT EAR CHAMBER WITH PARTICULAR REFERENCE TO THE PHENOMENON OF LEUKOCYTIC MIGRATION

    PubMed Central

    Cliff, W. J.

    1966-01-01

    Responses to injections of various materials into rabbit ear chambers were studied by in vivo microscopy. The acute inflammatory responses provoked by injections of antibody-antigen complexes were both quantitatively and qualitatively different from the responses obtained after injections of either homologous sera or the antigens alone. The sticking of leukocytes to endothelium during these responses occurred only in the venules draining the injection sites and was frequently present only on the sides of the venules towards the injection sites. An explanation of this finding was proposed in terms of absorption by the minute vessels related to the injection sites of postulated mediator(s) with specific activity on venular endothelium. Analysis of the rates and direction of movement of leukocytes during the reactions produced by the antibody-antigen complexes was performed with the aid of time-lapse cinemicroscopy. The leukocytes that were sticking to the venular endothelium frequently exhibited amoeboid locomotion within the vessels. Twice as many of these cells moved against the direction of blood flow as with it. This finding was discussed and an explanation proposed. A method for detecting a drift in the overall population of emigrated leukocytes within the inflamed tissue was described and revealed that four times as many amoeboid cells moved away from the injection sites as towards them. This result was discussed in the light of the in vitro chemotactic properties of antibody-antigen complexes demonstrated for rabbit leukocytes. An alternative explanation was proposed in terms of variation in the population density of these cells and their random movements and collisions. The rates of amoeboid movement of leukocytes during the acute inflammatory reactions produced by antibody-antigen complexes were similar to the rates found during turpentine inflammation and were compared to other published values. PMID:5922284

  16. [Raynaud's phenomenon].

    PubMed

    Tomčík, Michal

    2016-01-01

    Raynaud's phenomenon (RP) is a very common sign which can usually be seen across all medical specialties. It is characterized by episodic color changes of acral parts of the body (palor, cyanosis, rubor) lasting from a few minutes to hours, which are usually triggered by cold temperature and/or stress. The primary RP occurs alone, without concomitant diseases, is usually benign and has favorable prognosis. Secondary RP occurs in a variety of diseases with a very variable progression and prognosis, mostly unfavorable one due to the development of ischemic tissue necrosis and gangrene. This work provides a comprehensive overview of the history, current knowledge about the epidemiology and pathogenesis and the recommended evaluation and treatment of RP.

  17. Raynaud's phenomenon.

    PubMed

    Hughes, Michael; Herrick, Ariane L

    2016-02-01

    Raynaud's phenomenon (RP) is a major cause of pain and disability in patients with autoimmune connective tissue diseases (CTDs), particularly systemic sclerosis (SSc). The clinician must perform a comprehensive clinical assessment in patients with RP to differentiate between primary (idiopathic) and secondary RP, in particular (for rheumatologists), secondary to an autoimmune CTD, as both the prognosis and treatment may differ significantly. Key investigations are nailfold capillaroscopy and testing for autoantibodies (in particular, those associated with SSc). Patients with RP and either abnormal nailfold capillaroscopy or an SSc-specific antibody (and especially with both) have a high risk of transitioning to an autoimmune CTD. Both nailfold capillaroscopy and autoantibody specificity may help the clinician in predicting organ-based complications. The management of CTD-associated RP requires a multifaceted approach to treatment, including patient education and conservative ('non-drug') measures. Patients with CTD-associated RP often require pharmacological treatment, which in the first instance is usually a calcium channel blocker, although other agents can be used. There is an increasing tendency to use phosphodiesterase type 5 inhibitors early in the treatment of CTD-associated RP. Oral therapies are commonly associated with side effects (often due to systemic vasodilation) that may result in failure of dose escalation and/or permanent discontinuation. Intravenous prostanoid therapy and surgery (e.g., botulinum toxin injection and digital sympathectomy) can be considered in severe RP. Patients with CTD-associated RP can develop a number of ischaemic digital complications (primarily ulcers and critical ischaemia), which may be associated with significant tissue loss. Future research is required to increase the understanding of the pathogenesis and natural history of RP (to drive therapeutic advances), and to explore/develop drug therapies, including those that

  18. What Is Raynaud's Phenomenon?

    MedlinePlus

    ... Phenomenon PDF Version Size: 59 KB November 2014 What Is Raynaud’s Phenomenon? Fast Facts: An Easy-to- ... use tools that vibrate, such as a jackhammer. What Are the Symptoms of Raynaud’s Phenomenon? The body ...

  19. Mucocutaneous Splendore-Hoeppli phenomenon.

    PubMed

    Hussein, Mahmoud R

    2008-11-01

    Splendore-Hoeppli phenomenon (asteroid bodies) is the in vivo formation of intensely eosinophilic material (radiate, star-like, asteroid or club-shaped configurations) around microorganisms (fungi, bacteria and parasites) or biologically inert substances. This study presents a literature review concerning Splendore-Hoeppli reaction in the mucocutaneous diseases. It examines the histopathological features, nature and differential diagnosis of this reaction. It also discusses the mucocutaneous infections and the non-infective diseases associated with it. Available studies indicate that several mucocutaneous infections can generate Splendore-Hoeppli reaction. The fungal infections include sporotrichosis, pityrosporum folliculitis, zygomycosis, candidiasis, aspergillosis and blastomycosis. The bacterial infections include botryomycosis, nocardiosis and actinomycosis. The parasitic conditions include orbital pythiosis, strongyloidiasis, schistosomiasis and cutaneous larva migrans. In addition, Splendore-Hoeppli reaction may be seen with non-infective pathology such as hypereosinophilic syndrome and allergic conjunctival granulomas. The Splendore-Hoeppli reaction material comprises antigen-antibody complex, tissue debris and fibrin. Although the exact nature of this reaction is unknown, it is thought to be a localized immunological response to an antigen-antibody precipitate related to fungi, parasites, bacteria or inert materials. The characteristic formation of the peribacterial or perifungal Splendore-Hoeppli reaction probably prevents phagocytosis and intracellular killing of the insulting agent leading to chronicity of infection. To conclude, Splendore-Hoeppli reaction is a tell tale of a spectrum of infections and reactive conditions. The molecular pathways involved in the development of this reaction are open for future investigations.

  20. [Phenomenon of dental fear].

    PubMed

    Moore, R; Birn, H

    1990-01-01

    Odontophobia is a rather unique phobia with special psychosomatic components that impact on the dental health of odontophobic persons. It also has psychosocial components largely as a result of destruction of the teeth and subsequent embarrassment that can affect a person and cause a vicious cycle of dental fear. The phenomenon is facilitated by misunderstandings and myths generated by both patients and dentists. The most common reasons given in the literature for such strong fears of dental treatment are: 1) bad experiences in childhood for 85% of cases, 2) feeling of powerlessness and lack of control over personal emotional reactions and over the social situation in the dental chair, 3) social learning processes in which the image of the dentist is cast in a negative light by the mass media or by the person's relatives or friends and 4) that the person has other psychologic problems (in 20% of cases), such as serious phobias and/or neuroses. A strategy of researching and thus tackling the problem is presented which focuses on three essential targets that require studying and change: 1) the community at large and their image of the dentist, 2) the patient role and 3) the dentist role. Various model projects are presented along with their diagnostic systems. These are seen to focus in varying degrees on different elements of the target groups that effect the dentist-patient relationship but the need to come out into the community and make the social environment right for these patients is an important factor in all strategies.(ABSTRACT TRUNCATED AT 250 WORDS)

  1. Pathogenesis of Raynaud's phenomenon.

    PubMed

    Herrick, A L

    2005-05-01

    The pathogenesis of Raynaud's phenomenon is not fully understood. However, the last 20 yr have witnessed enormous increases in our understanding of different mechanisms which, singly or in combination, may contribute. A key point is that Raynaud's phenomenon can be either primary (idiopathic) or secondary to a number of underlying conditions, and that the pathogenesis and pathophysiology vary between these conditions. This review concentrates upon those subtypes of Raynaud's phenomenon of most interest to rheumatologists: systemic sclerosis-related Raynaud's phenomenon, primary Raynaud's phenomenon and Raynaud's phenomenon secondary to hand-arm vibration syndrome. In this review, I shall discuss the main mechanisms thought to be important in pathophysiology under the three broad headings of 'vascular', 'neural' and 'intravascular'. While these are false distinctions because all interrelate, they facilitate discussion of the key elements: the blood vessel wall (particularly the endothelium), the neural control of vascular tone, and the many circulating factors which can impair blood flow and/or cause endothelial injury. Vascular abnormalities include those of both structure and function. Neural abnormalities include deficiency of the vasodilator calcitonin gene-related peptide (released from sensory afferents), alpha(2)-adrenoreceptor activation (possibly with up-regulation of the normally 'silent' alpha(2C)-adrenoreceptor) and a central nervous system component. Intravascular abnormalities include platelet activation, impaired fibrinolysis, increased viscosity and probably oxidant stress. As our understanding of the pathophysiology of Raynaud's phenomenon increases, so do our possibilities for identifying effective treatments.

  2. A new phenomenon?

    NASA Astrophysics Data System (ADS)

    Ganci, S.

    2017-03-01

    This letter describes an interesting optical phenomenon engaging the reflected images of a new tube LED lamp (an array of high luminosity LEDs substituting the old fluorescent lamps) on any convex glossy black surface.

  3. Treatment of Raynaud's phenomenon.

    PubMed

    García-Carrasco, Mario; Jiménez-Hernández, Mario; Escárcega, Ricardo O; Mendoza-Pinto, Claudia; Pardo-Santos, Rodrigo; Levy, Roger; Maldonado, Claudio Galarza; Chávez, Gonzalo Pérez; Cervera, Ricard

    2008-10-01

    Raynaud's phenomenon is an episodic vasospasm of the peripheral arteries, causing pallor followed by cyanosis and redness with pain and sometimes paraesthesia, and, rarely, ulceration of the fingers and toes. Primary or idiopathic Raynaud's phenomenon (Raynaud's disease) occurs without an underlying disease. Secondary Raynaud's phenomenon (Raynaud's syndrome) occurs in association with an underlying disease. Initially conservative, non-pharmacologic approach is important for these patients, although pharmacologic therapy may ultimately be necessary. Advances in vascular physiology have showed the role of the endothelium as well as endothelium-independent mechanisms in the altered vasoregulation of Raynaud's phenomenon. This has opened promising therapeutic avenues, and it is likely that therapies targeted towards specific pathophysiologic steps become available in the near future.

  4. The Root Pressure Phenomenon

    ERIC Educational Resources Information Center

    Marsh, A. R.

    1972-01-01

    Describes experiments demonstrating that root pressure in plants is probably controlled by a circadian rhythm (biological clock). Root pressure phenomenon plays significant part in water transport in contradiction with prevalent belief. (PS)

  5. The Leidenfrost Phenomenon

    ERIC Educational Resources Information Center

    Curzon, F. L.

    1978-01-01

    Describes four demonstrations of the Leidenfrost phenomenon; floating of liquid drops on their own vapor above a hot surface, delayed quenching of red-hot brass by water, explosion of vessels containing suspended liquid droplets, and momentary incombustibility of living tissue immersed in boiling oil. (Author/GA)

  6. Raynaud's phenomenon in children.

    PubMed

    Ortega Vicente, Elena; Garrido Redondo, Mercedes

    Raynaud's Phenomenon is caused by spasm of the small arteries and arterioles of the fingers. It is triggered by various stimuli including exposure to cold or a stressful event. It may be symmetrical or wrap one end. The appearance of this entity in children is rare. We report the case of a 4 year old male consultation health center by episodes of coldness, pallor and pain in both feet.

  7. Vacuum phenomenon: Clinical relevance.

    PubMed

    Gohil, Ishan; Vilensky, Joel A; Weber, Edward C

    2014-04-01

    Vacuum phenomenon (VP) is an anatomical entity of potential confusion in the diagnosis and evaluation of joint pathology. Observation of this phenomenon has been demonstrated on basic radiographs, computed tomography, and magnetic resonance imaging. Although VP is most often associated with degenerative joint disease, it is observed with other pathologies. Two problematic scenarios can occur: a false-positive diagnosis of serious pathology instead of benign VP and a false-negative diagnosis of benign VP with a more serious underlying process Despite this potential for confusion, criteria for distinguishing VP from other causes of joint pain and for evaluating a suspected case of VP have not been fully established. We reviewed the literature to determine underlying mechanism, symptomology, associated pathologies, and clinical importance of VP. The formation of VP can be explained by gas solubility, pressure-volume relationships, and human physiology. CT, GRE-MRI, and multipositional views are the best imaging studies to view VP. Although most cases of VP are benign, it can be associated with clinical signs and symptoms. VP outside the spine is an underreported finding on imaging studies. VP should be on the differential diagnosis for joint pain, especially in the elderly. We have proposed criteria for diagnosing VP and generated a basic algorithm for its workup. Underreporting of this phenomenon shows a lack of awareness of VP on the part of physicians. By identifying true anatomic VP, we can prevent harm from suboptimal treatment of patients.

  8. Translation as a psycholinguistic phenomenon.

    PubMed

    Zasyekin, Serhiy

    2010-06-01

    The article sketches the outlines of a theoretical framework for the analysis of translation of literary texts, viewed as psycho-semiotic phenomenon and based on evaluation of earlier attempts in this direction, and on the results of a psycholinguistic empirical study of translations. Central to this framework is the recent insight that the human cerebral hemisphere functional asymmetry somehow plays a role in structuring the fictional text by its author and in its processing by the interpreter. It is argued that the texts of modernism and post-modernism contain information blocks describing a character's perception of events in altered states of consciousness. This model helps to explain how a translator's inappropriate linguistic choice may influence the target language reader's aesthetic reaction.

  9. The neutron channeling phenomenon.

    PubMed

    Khanouchi, A; Sabir, A; Boulkheir, M; Ichaoui, R; Ghassoun, J; Jehouani, A

    1997-01-01

    Shields, used for protection against radiation, are often pierced with vacuum channels for passing cables and other instruments for measurements. The neutron transmission through these shields is an unavoidable phenomenon. In this work we study and discuss the effect of channels on neutron transmission through shields. We consider an infinite homogeneous slab, with a fixed thickness (20 lambda, with lambda the mean free path of the neutron in the slab), which contains a vacuum channel. This slab is irradiated with an infinite source of neutrons on the left side and on the other side (right side) many detectors with windows equal to 2 lambda are placed in order to evaluate the neutron transmission probabilities (Khanouchi, A., Aboubekr, A., Ghassoun, J. and Jehouani, A. (1994) Rencontre Nationale des Jeunes Chercheurs en Physique. Casa Blanca Maroc; Khanouchi, A., Sabir, A., Ghassoun, J. and Jehouani, A. (1995) Premier Congré International des Intéractions Rayonnements Matière. Eljadida Maroc). The neutron history within the slab is simulated by the Monte Carlo method (Booth, T. E. and Hendricks, J. S. (1994) Nuclear Technology 5) and using the exponential biasing technique in order to improve the Monte Carlo calculation (Levitt, L. B. (1968) Nuclear Science and Engineering 31, 500-504; Jehouani, A., Ghassoun, J. and Aboubker, A. (1994) In Proceedings of the 6th International Symposium on Radiation Physics, Rabat, Morocco). Then different geometries of the vacuum channel have been studied. For each geometry we have determined the detector response and calculated the neutron transmission probability for different detector positions. This neutron transmission probability presents a peak for the detectors placed in front of the vacuum channel. This study allowed us to clearly identify the neutron channeling phenomenon. One application of our study is to detect vacuum defects in materials.

  10. Docetaxel-induced photo-recall phenomenon.

    PubMed

    Droitcourt, Catherine; Le Hô, Hélêne; Adamski, Henri; Le Gall, François; Dupuy, Alain

    2012-08-01

    Photo-recall phenomenon is a phototoxic eruption occurring on areas of previous ultraviolet-induced solar erythema following a systemic administration of a drug. It has been mostly described with methotrexate but remains rare with other antineoplastic drugs. We describe a case of docetaxel-induced photo-recall skin rash in a woman treated for a non-small-cell lung cancer. Although the patient has refused to receive a second infusion, chemotherapy can be carried on with photoprotection and the use of topical and/or systemic corticosteroids. In contrast, radiation recall is a well-known reaction by oncologists, most of them may not be aware of a similar phenomenon called photo-recall phenomenon. Recognizing this entity may avoid misdiagnosing a drug allergy and should avoid inappropriate decisions of drug discontinuation.

  11. Cozen's phenomenon: a reminder.

    PubMed

    Dorman, S; Jariwala, A; Campbell, D

    2013-08-01

    A four-year-old child attended Accident and Emergency following a fall from a slide with a displaced and angulated proximal tibial metaphyseal fracture. Treatment included closed manipulation under anaesthesia and an above knee cast for seven weeks. Serial radiographs over the following few months were satisfactory demonstrating good alignment and evidence of healing. However, at four-months review new-onset genu valgum with mechanical axis deviation was noted. No evidence of spontaneous resolution was noted over the following 12 months and hence a corrective hemi-epiphysiodesis was performed. At 12-months post-operatively, there was marked clinical and radiographical improvement in alignment. Classically Cozen's phenomenon is described as the late-onset post-traumatic valgus deformity associated with proximal tibial metaphyseal fractures in children. We want to reemphasise the early recognition of children at risk of this unique complication. In addition, we wish to highlight the progression of the late-onset valgus and its subsequent management.

  12. [Raynaud's phenomenon: pathogenesis and prevalence].

    PubMed

    Mikulska, Danuta

    2010-01-01

    Raynaud's phenomenon is defined as occasional ischemia of the distal parts of the extremities. Ischemia may be idiopathic as in primary Raynaud's disease or instigated by a comorbidity as in Raynaud's syndrome. Opinions on the etiopathogenesis of Raynaud's phenomenon have changed during recent years. Research has shown that enhanced vascular reactivity is attributable more to local factors and less to abnormalities in the central nervous system. Local factors are classified as vascular, nervous, and intravascular. Changes in our understanding of the etiopathogenesis of Raynaud's phenomenon have resulted in modified therapeutic guidelines. The present work reviews current opinions on the etiopathogenesis of Raynaud's phenomenon.

  13. Lucio's phenomenon: exuberant case report and review of Brazilian cases*

    PubMed Central

    Rocha, Rafael Henrique; Emerich, Paulo Sergio; Diniz, Lucia Martins; de Oliveira, Marcela Bahia Barretto; Cabral, Aline Neves Freitas; do Amaral, Ana Cristina Vervloet

    2016-01-01

    Lucio’s phenomenon is an uncommon reaction characterized by severe necrotizing cutaneous lesions that occurs in patients with Lucio’s leprosy and lepromatous leprosy. It is considered by some authors as a variant of type 2 or 3 reaction. Death can occur because of blood dyscrasia or sepsis. Precipitating factors include infections, drugs and pregnancy. We report a 31-year-old female patient exhibiting both clinical and histopathological features of lepromatous leprosy and Lucio’s phenomenon presenting favorable response to treatment. We complement our report with a literature review of the Brazilian cases of Lucio’s phenomenon published in Portuguese and English. PMID:28300896

  14. Theory of the shimmy phenomenon

    NASA Astrophysics Data System (ADS)

    Zhuravlev, V. Ph.; Klimov, D. M.

    2010-06-01

    The shimmy phenomenon is the appearance of angular self-excited vibrations of the carriage wheels. Such self-excited vibrations provide a serious safety hazard for motion, which explains the great interest of scientists in this phenomenon [1-6]. This problem is most serious for the aircraft fore wheels. It is commonly agreed that themain cause of the shimmyphenomenon is the tyre deformation [2]. We do not doubt this thesis, but still we note that this cause is not unique. The shimmy phenomenon can be observed in everyday life in the case of various hand trucks with rigid wheels, where the reference to the elastic tyre is out of place. In what follows, we show that the theory of polycomponent dry friction can completely explain the shimmy phenomenon for absolutely rigid wheels, and hence can be at least one of the causes of this phenomenon in the general case. Dry friction has been ignored by the scientists in their explanations of the shimmy phenomenon, because this friction has not been fully investigated until now, and it has been impossible to explain the shimmy phenomenon in the framework of the former representations.

  15. The phenomenon of fluorescence in immunosensors.

    PubMed

    Kłos-Witkowska, Aleksandra

    2016-01-01

    The phenomenon of fluorescence in immunosensors is described in this paper. Both structure and characteristics of biosensors and immunosensors are presented. Types of immunosensors and the response of bioreceptor layers to the reaction with analytes as well as measurements of electrochemical, piezoelectric and optical parameters in immunosensors are also presented. In addition, detection techniques used in studies of optical immunosensors based on light-matter interactions (absorbance, reflectance, dispersion, emission) such as: UV/VIS spectroscopy, reflectometric interference spectroscopy (RIfs), surface plasmon resonance (SPR), optical waveguide light-mode spectroscopy (OWLS), fluorescence spectroscopy. The phenomenon of fluorescence in immunosensors and standard configurations of immunoreactions between an antigen and an antibody (direct, competitive, sandwich, displacement) is described. Fluorescence parameters taken into account in analyses and fluorescence detection techniques used in research of immunosensors are presented. Examples of immunosensor applications are given.

  16. [Raynaud's phenomenon, disease or syndrome?].

    PubMed

    Fiessinger, Jean-Noël

    2011-09-01

    Raynaud's phenomenon is a common symptom. More often it is usually an idiopathic and benign condition. But it can be an early manifestation of a connective tissue disease especially scleroderma and primary Sjogren's syndrom. Thus it is necessary to develop reasonable screening model. If the vasomotor symptoms are localized, a diagnosis of secondary Raynaud's phenomenon is highly probable and the main etiology is an arterial disease. Occupational arterial lesions are a particularly aspect of secondary Raynaud's phenomenon. Calcium channel blockers are the reference for the symptomatic treatment of Raynaud's phenomenon. In severe secondary forms, intravenous iloprost infusion is effective. New drugs as endothelin antagonist and phospodiesterase type 5 inhibitors are still to be evaluated.

  17. [Methylphenidate and secondary Raynaud's phenomenon].

    PubMed

    Iglesias Otero, M; Portela Romero, M; Bugarín González, R; Ventura Victoria, M A

    2013-09-01

    Raynaud's phenomenon is a clinical disease characterized by episodic attacks of vasoconstriction of the arteries and arterioles of the extremities such as fingers and toes, sometimes the ears and nose, in response to cold or emotional stimuli. A classic attack is the pallor of the distal extremity, followed by cyanosis and redness, accompanied by paresthesia, usually as heat. When it occurs without apparent cause is called primary Raynaud's phenomenon. When associated with other disease, is called secondary Raynaud's phenomenon. The secondary table is associated with increased frequency of rheumatic diseases of collagen. They can also present certain drugs that cause vasoconstriction, such as ergotamine, beta-adrenergic antagonists, contraception and sympathomimetic drugs. Regarding the latter, we present a case of Raynaud's phenomenon secondary to methylphenidate in a 14 years.

  18. Nutcracker phenomenon and nutcracker syndrome.

    PubMed

    Kurklinsky, Andrew K; Rooke, Thom W

    2010-06-01

    Nutcracker phenomenon refers to compression of the left renal vein, most commonly between the aorta and the superior mesenteric artery, with impaired blood outflow often accompanied by distention of the distal portion of the vein. The nutcracker syndrome (NCS) is the clinical equivalent of nutcracker phenomenon characterized by a complex of symptoms with substantial variations. Depending on specific manifestations, NCS may be encountered by different medical specialists. Although it may be associated with substantial morbidity, the diagnosis of NCS is often difficult and is commonly delayed. Diagnostic and treatment criteria are not well established, and the natural history of NCS is not well understood. We performed an initial review of the literature through MEDLINE, searching from 1950 to date and using the keywords nutcracker syndrome, nutcracker phenomenon, and renal vein entrapment. We performed additional reviews based on the literature citations of the identified articles. We attempted to elucidate clinical relevance of these conditions and their prominent features and to summarize professional experience.

  19. Translation as a Psycholinguistic Phenomenon

    ERIC Educational Resources Information Center

    Zasyekin, Serhiy

    2010-01-01

    The article sketches the outlines of a theoretical framework for the analysis of translation of literary texts, viewed as psycho-semiotic phenomenon and based on evaluation of earlier attempts in this direction, and on the results of a psycholinguistic empirical study of translations. Central to this framework is the recent insight that the human…

  20. Religion as a Natural Phenomenon

    ScienceCinema

    Dennett, Daniel [Tufts University, Boston, Massachusetts, United States

    2016-07-12

    Religion is a costly human activity that has evolved over the millennia. Why does it exist and how does it foster such powerful allegiances? To undertake a serious scientific study of religious practices and attitudes we must set aside a traditional exemption from scrutiny which religions have enjoyed. Religious adherents may not welcome this attention, but we should press ahead with it, since if we don't come to understand religion as a natural phenomenon, our attempts to deal with the problems that loom in the twenty-first century will likely be counterproductive.

  1. Religion as a Natural Phenomenon

    SciTech Connect

    Dennett, Daniel

    2006-02-15

    Religion is a costly human activity that has evolved over the millennia. Why does it exist and how does it foster such powerful allegiances? To undertake a serious scientific study of religious practices and attitudes we must set aside a traditional exemption from scrutiny which religions have enjoyed. Religious adherents may not welcome this attention, but we should press ahead with it, since if we don't come to understand religion as a natural phenomenon, our attempts to deal with the problems that loom in the twenty-first century will likely be counterproductive.

  2. Cell phenomenology: The first phenomenon.

    PubMed

    Pattee, H H

    2015-12-01

    As a broad academic discipline phenomenology may be summarized as the study from a first person point of view of what appears to subjective human conscious experience. As a historical philosophical movement phenomenology was often motivated by the belief that subjective human experience is the proper foundation of all philosophy. I explore phenomena from a broader evolutionary and physical point of view. I consider a phenomenon as the subjective consequence of a physical interaction with an individual organism. In physical terms, a phenomenon requires some form of detection or measurement. What is detected is determined by the organism, and is potentially functional for the organism as a self or subject. The concept of function has meaning only for living organisms. The classical human mind-body problem is an ill-defined complicated case of the more general epistemic subject-object problem, which at the origin of life I reduce to the primitive symbol-matter problem. I argue that the first memory-based self-replicating unit, like a cell, is the most primitive case of a necessary symbol-matter distinction. The first phenomena, which include all forms or sensing, detection, and measurement, require a subject-object distinction, called the epistemic cut. It is only because of such a subject-object distinction that populations of individual subjects can selectively adapt to their environment by heritable variations. This basic evolutionary process requires distinguishing the individual's subjective phenomena from the objective events of inexorable physical laws.

  3. Water condensation: a multiscale phenomenon.

    PubMed

    Jensen, Kasper Risgaard; Fojan, Peter; Jensen, Rasmus Lund; Gurevich, Leonid

    2014-02-01

    The condensation of water is a phenomenon occurring in multiple situations in everyday life, e.g., when fog is formed or when dew forms on the grass or on windows. This means that this phenomenon plays an important role within the different fields of science including meteorology, building physics, and chemistry. In this review we address condensation models and simulations with the main focus on heterogeneous condensation of water. The condensation process is, at first, described from a thermodynamic viewpoint where the nucleation step is described by the classical nucleation theory. Further, we address the shortcomings of the thermodynamic theory in describing the nucleation and emphasize the importance of nanoscale effects. This leads to the description of condensation from a molecular viewpoint. Also presented is how the nucleation can be simulated by use of molecular models, and how the condensation process is simulated on the macroscale using computational fluid dynamics. Finally, examples of hybrid models combining molecular and macroscale models for the simulation of condensation on a surface are presented.

  4. Are Earthquakes a Critical Phenomenon?

    NASA Astrophysics Data System (ADS)

    Ramos, O.

    2014-12-01

    Earthquakes, granular avalanches, superconducting vortices, solar flares, and even stock markets are known to evolve through power-law distributed events. During decades, the formalism of equilibrium phase transition has coined these phenomena as critical, which implies that they are also unpredictable. This work revises these ideas and uses earthquakes as the paradigm to demonstrate that slowly driven systems evolving through uncorrelated and power-law distributed avalanches (UPLA) are not necessarily critical systems, and therefore not necessarily unpredictable. By linking the correlation length to the pdf of the distribution, and comparing it with the one obtained at a critical point, a condition of criticality is introduced. Simulations in the classical Olami-Feder-Christensen (OFC) earthquake model confirm the findings, showing that earthquakes are not a critical phenomenon. However, one single catastrophic earthquake may show critical properties and, paradoxically, the emergence of this temporal critical behaviour may eventually carry precursory signs of catastrophic events.

  5. Skin Reactions to Cold

    PubMed Central

    Talpash, Orest

    1976-01-01

    Although skin reactions to cold are seen surprisingly infrequently in Canada, it is important to manage them correctly when they do occur. Frostbite, cold urticarias, Raynaud's disease and phenomenon, and several miscellaneous changes are discussed. PMID:21308019

  6. The phenomenon of Soviet science.

    PubMed

    Kojevnikov, Alexei

    2008-01-01

    The grand "Soviet experiment" constituted an attempt to greatly accelerate and even shortcut the gradual course of historical development on the assumption of presumed knowledge of the general laws of history. This paper discusses the parts of that experiment that directly concerned scientific research and, in fact, anticipated or helped define important global changes in the functioning of science as a profession and an institution during the twentieth century. The phenomenon of Soviet, or socialist, science is analyzed here from the comparative international perspective, with attention to similarities and reciprocal influences, rather than to the contrasts and dichotomies that have traditionally interested cold war-type historiography. The problem is considered at several levels: philosophical (Soviet thought on the relationship between science and society and the social construction of scientific knowledge); institutional (the state recognition of research as a separate profession, the rise of big science and scientific research institutes); demographic (science becoming a mass profession, with ethnic and gender diversity among scientists); and political (Soviet-inspired influences on the practice of science in Europe and the United States through the social relations of science movement of the 1930s and the Sputnik shock of the 1950s).

  7. Life as a planetary phenomenon.

    PubMed

    Owen, T

    1985-01-01

    The success of recent spacecraft from the U.S.A. and the U.S.S.R. has given us a wealth of new data about the planets in our solar system. We can now develop a much better rationale for the reasons that abundant life is only found on our planet. Mars, smaller and more distant from the Sun, may nevertheless hold clues to the early development of Earth's atmosphere. The origin of life on Mars early in that planet's history cannot be ruled out. Titan offers a contemporary example of extremely primitive conditions, where chemical reactions resembling those that preceded the development of life on Earth may be occurring today. Venus and Jupiter illustrate the need for a planet to be the right size and the right distance from the sun if chemical evolution leading to the origin of life is to occur.

  8. STUDIES ON THE MECHANISM OF THE SHWARTZMAN PHENOMENON

    PubMed Central

    Stetson, Chandler A.

    1955-01-01

    The cutaneous, ophthalmic, and systemic reactions of normal rabbits to Gram-negative bacterial endotoxins have been compared with the classical reactions of bacterial hypersensitivity, and in each case certain similarities have been found. It has also been shown that the Shwartzman phenomenon can be reproduced with tuberculin, in BCG-vaccinated rabbits, and with suspensions or extracts of heat-killed Group A streptococci in rabbits previously sensitized to these bacteria. These considerations suggest the hypothesis that the biologic activity of endotoxins may be based on the existence in "normal" animals of delayed or tuberculin-type hypersensitivity to these materials. PMID:14354110

  9. Monostotic fibrous dysplasia with Raynaud's phenomenon

    PubMed Central

    Kumar, K. V. S. Hari; Aravinda, K.; Narayanan, K.

    2015-01-01

    Fibrous dysplasia (FD) is a benign bone disorder characterized by alteration in bone morphology. Monostotic FD is the commonest variant and affects the craniofacial bones. Raynaud's phenomenon is recurrent vasospasm of the fingers and toes due to cold exposure. The disease is usually idiopathic or secondary to connective tissue disorders. Raynaud's phenomenon is not described previously with FD. We recently encountered two interesting patients of craniofacial monostotic FD with Raynaud's phenomenon and report the same in this report. PMID:26283854

  10. Monostotic fibrous dysplasia with Raynaud's phenomenon.

    PubMed

    Kumar, K V S Hari; Aravinda, K; Narayanan, K

    2015-01-01

    Fibrous dysplasia (FD) is a benign bone disorder characterized by alteration in bone morphology. Monostotic FD is the commonest variant and affects the craniofacial bones. Raynaud's phenomenon is recurrent vasospasm of the fingers and toes due to cold exposure. The disease is usually idiopathic or secondary to connective tissue disorders. Raynaud's phenomenon is not described previously with FD. We recently encountered two interesting patients of craniofacial monostotic FD with Raynaud's phenomenon and report the same in this report.

  11. The Isakower phenomenon revisited: a case study.

    PubMed

    Dann, O T

    1992-01-01

    The Isakower phenomenon is a situation in which an individual typically experiences perceptions of enlargement or thickening, altered states of consciousness, sensations of floating, and impressions of the emergence and disappearance of an oral mass. This paper defines the phenomenon, reviews the literature, and describes a case in which a patient experienced it. The patient manifested the phenomenon symptomatically in the aftermath of a toxic state, and the elements were analysed for several years. There was support for Isakower's original thesis that the regressive states serve to defend against threatening incestuous fantasies. However, the Isakower phenomenon in this patient was the result of a multiplicity of determinants, largely defensive, involving many developmental levels.

  12. Electron string phenomenon: physics and use

    NASA Astrophysics Data System (ADS)

    Donets, Evgeny D.

    2004-01-01

    Electron string phenomenon arises as a result of phase transition of a state of multiply reflected electron beam to this new discovered state of one component electron plasma and can be easily observed in the reflex mode of EBIS operation. The transition goes via a strong instability, which causes considerable electron energy spread, which in its turn suppresses the instability. Electron string state is a stationary state of hot pure electron plasma, which is heated by injected electron beam and cooled because of electron loses. Electron string is quiet in broad regions of experimental parameters, so that it is used for confinement and ionization of positive ions by electron impact to highly charge states similar to electron beams in EBIS. Application of electron strings instead of electron beams for ion production allows to save about 99% of electric power of electron beam and simultaneously to improve reliability of an ion source considerably. The JINR EBIS `Krion-2' in the string mode of operation is used for production of N7+, Ar16+ and Fe24+ ion beams and their acceleration to relativistic energies on the facility of the JINR super conducting one turn injection synchrotron `Nuklotron'. The tubular electron string possibly can exist and it is under study now theoretically and experiments are prepared now. Estimations show that a Tubular Electron String Ion Source (TESIS) could have up to three orders of magnitude higher ion output then a Linear one (LESIS). In frames of nuclear astrophysics electron strings can be used for research of fusion nuclear reactions at low energies in conditions when both beam and target nuclei do not carry orbital electrons. The project NARITA — Nuclear Astrophysics Researches in an Ion Trap Apparatus is proposed. Polarization effects also can be studied.

  13. A classical case of the Gasul phenomenon.

    PubMed

    Sabnis, Girish R; Phadke, Milind S; Kerkar, Prafulla G

    2016-02-01

    This case demonstrates the development of secondary infundibular stenosis in a 10-year-old male child with documented large non-restrictive perimembranous ventricular septal defect in infancy - the classical Gasul phenomenon.

  14. Validation of the Impostor Phenomenon among Managers

    PubMed Central

    Rohrmann, Sonja; Bechtoldt, Myriam N.; Leonhardt, Mona

    2016-01-01

    Following up on earlier investigations, the present research aims at validating the construct impostor phenomenon by taking other personality correlates into account and to examine whether the impostor phenomenon is a construct in its own right. In addition, gender effects as well as associations with dispositional working styles and strain are examined. In an online study we surveyed a sample of N = 242 individuals occupying leadership positions in different sectors. Confirmatory factor analyses provide empirical evidence for the discriminant validity of the impostor phenomenon. In accord with earlier studies we show that the impostor phenomenon is accompanied by higher levels of anxiety, dysphoric moods, emotional instability, a generally negative self-evaluation, and perfectionism. The study does not reveal any gender differences concerning the impostor phenomenon. With respect to working styles, persons with an impostor self-concept tend to show perfectionist as well as procrastinating behaviors. Moreover, they report being more stressed and strained by their work. In sum, the findings show that the impostor phenomenon constitutes a dysfunctional personality style. Practical implications are discussed. PMID:27313554

  15. PP composites with Hybrid Nanofillers: NTC phenomenon

    NASA Astrophysics Data System (ADS)

    Sarlin, Juha; Immonen, Kirsi

    2010-06-01

    Electric conductive plastic composites have a wide potential for commercial applications, some examples are EMI shielding housings and components in automotive industry and in consumer electronics, equipments in health care sector and fuel cell components. A phenomenon in conductive composites, especially in composites with carbon based fillers, is change of thermal induced change in conductivity as a result of morphological transitions. Usually the observed changes are practically irreversible. The phenomenon may cause increasing resistivity, usually called as "positive temperature coefficient" (PTC) or decreasing resistivity, called "negative temperature coefficient (NTC), where the new morphology created by heat treatment is more favorable for electric conductivity compared to the original state. The existence of NTC is a sing of the lost potential in material design and processing. Therefore detailed information about the phenomenon gives us tools to develop high performance conductive materials. It this paper we discuss about NTC phenomenon observed in PP composites with CNT or in-situ synthesized CNT-PANi hybrid nanofiller with an amphiphilic dispersing agent. The goal of the paper is not to present a comprehensive model of this phenomenon; we present some experimental results which may be related to polymer-filler interactions. These details are a part of this complicated phenomenon.

  16. SODIUM-WATER HEAT EXCHANGER

    DOEpatents

    Simmons, W.R.; Koch, L.J.

    1962-04-17

    A heat exchanger comprising a tank for hot liquid and a plurality of concentric, double tubes for cool liquid extending vertically through the tank is described. These tubes are bonded throughout most of their length but have an unbonded portion at both ends. The inner tubes extend between headers located above and below the tanmk and the outer tubes are welded into tube sheets forming the top and bottom of the tank at locations in the unbonded portions of the tubes. (AEC)

  17. Investigation of ozone zero phenomenon using new electrode and surface analysis technique

    NASA Astrophysics Data System (ADS)

    Taguchi, M.; Ochiai, Y.; Kawagoe, R.; Kato, Y.; Teranishi, K.; Suzuki, S.; Itoh, H.

    2011-07-01

    Results of our experimental investigation on the ozone zero phenomenon suggested us the importance of the electrode surface condition. This means that the main cause of the phenomenon, that is, temporal decrease of ozone concentration at the outlet of DBD type ozone generator and the recovery characteristics from the phenomenon are considered as the surface reaction process, which are influenced strongly by the surface condition. The surface condition is never constant during the ozone generation and varies gradually or remarkably with time depending on the experimental conditions. Therefore we have been continued to make clear the cause of the phenomenon, for example, the reproducibility of the phenomenon, using new electrodes and together with the surface analysis technique etc. In this paper, we describe on the above results and discussion.

  18. Stability of the discretization of the electron avalanche phenomenon

    SciTech Connect

    Villa, Andrea; Barbieri, Luca; Gondola, Marco; Leon-Garzon, Andres R.; Malgesini, Roberto

    2015-09-01

    The numerical simulation of the discharge inception is an active field of applied physics with many industrial applications. In this work we focus on the drift-reaction equation that describes the electron avalanche. This phenomenon is one of the basic building blocks of the streamer model. The main difficulty of the electron avalanche equation lies in the fact that the reaction term is positive when a high electric field is applied. It leads to exponentially growing solutions and this has a major impact on the behavior of numerical schemes. We analyze the stability of a reference finite volume scheme applied to this latter problem. The stability of the method may impose a strict mesh spacing, therefore a proper stabilized scheme, which is stable whatever spacing is used, has been developed. The convergence of the scheme is treated as well as some numerical experiments.

  19. Conjunctival Splendore-Hoeppli phenomenon in a 3-year-old child.

    PubMed

    Orhan, Diclehan; Kiratli, Hayyam; Kocabeyoğlu, Sibel

    2006-01-01

    A case of benign granulomas of the conjunctiva in a 3-year-old girl is reported. Histologic features of the excised conjunctival lesions were consistent with Splendore-Hoeppli phenomenon. This phenomenon is thought to be a granulomatous reaction to an antigen-antibody precipitate related to parasites or fungi. No causative agent is identified in our patient. Immunohistochemical analysis showed no immunoreactivity for immunoglobulin G (IgG), IgM, IgA, or the C3 component of the complement. We propose that the presence of small amelanotic nodular conjunctival tumors should arouse suspicion related to the Splendore-Hoeppli phenomenon even in early childhood.

  20. Aging phenomenon of stabilized bismuth oxides

    SciTech Connect

    Jiang, N.; Buchanan, R.M.; Henn, F.E.G.; Marshall, A.F.; Stevenson, D.A. . Dept. of Materials Science and Engineering); Washsman, E.D. . Materials Research Center)

    1994-03-01

    Stabilized bismuth oxides exhibit a decay in conductivity when annealed at temperatures below 600 C. The authors refer to this phenomenon as aging and it is distinct from a conventional crystallographic phase transformation. This phenomenon is revealed by an endotherm from DSC thermal analysis and results in the formation of a superstructure observable by TEM diffraction patterns, yet no change in structure is observable by XRD. Since oxygen vacancies are the mobile defects responsible for ionic conductivity, the authors attribute the aging process to the ordering of oxygen vacancies by an order-disorder transition below [approximately]600 C.

  1. First time description of dismantling phenomenon

    PubMed Central

    Barrer, Laurence; Gimenez, Guy

    2015-01-01

    Dismantling is a complex psychic phenomenon, which is not easy to define, and little interest has been shown in the subject. The authors of this paper want to demonstrate that dismantling is the main defense mechanism in autism, bringing about de-consensus of senses. The effects perceived in a child with autistic disorder are passivity and lack of thought. The authors’ purpose here is to define the dismantled state and reveal its underlying process. This paper will therefore describe for the first time in literature, the dismantling phenomenon and will submit a metapsychological approach of this defense mechanism. PMID:25999871

  2. Capecitabine-induced radiation recall phenomenon: a case report

    PubMed Central

    Aguilar, José

    2013-01-01

    Radiation recall dermatitis is defined as an inflammatory reaction of the skin at the site of previous irradiation. Different drugs have been associated with triggering this phenomenon, and it can also affect other areas and organs where previous radiotherapy has been administered. The time gap between the inflammatory reaction and previous radiation can range from days to several years. We report a case of capecitabine-induced Radiation Therapy Oncology Group (RTOG) grade 4 (ulcerating dermatitis) recall skin toxicity of skin irradiated 3 years previously. To our knowledge, this is the first reported case of capecitabine-induced RTOG grade 4 (ulcerating dermatitis) recall skin toxicity of previously irradiated skin. Clinicians should be aware of this phenomenon, even when considering patients for whom it has been a long time since previous radiation therapy. This unusual and late drug side effect should be borne in mind in the differential diagnosis and management of advanced-disease patients as it may be confused with local relapse or infectious complication of previously operated areas. PMID:24555020

  3. Facilitated Communication: The Clinical and Social Phenomenon.

    ERIC Educational Resources Information Center

    Shane, Howard C., Ed.

    This text explains the phenomenon of facilitated communication (FC) from an empirical, data-based, and/or clinical perspective. It is not a how-to-facilitate text, but one that explores the clinical and sociological reality of FC. A common theme running through each of the papers in the book is the question of FC's legitimacy. The papers reveal…

  4. A Phenomenon of Overqualification in Personnel Psychology

    ERIC Educational Resources Information Center

    Fine, Saul; Nevo, Baruch

    2007-01-01

    This study examines the concept of overqualification as a phenomenon of nonlinearity in the upper deciles of the ability-performance relationship. In three job contexts (military, academic, and industrial), the ability-performance relationship is characterized by a strong linear component below the mean and a ceiling effect at various points above…

  5. LED's and the "Fluttering Heart" Phenomenon.

    ERIC Educational Resources Information Center

    Jewett, John W., Jr.

    1993-01-01

    Describes the nineteenth-century parlor trick entitled the Fluttering Heart phenomenon which uses a red heart on a bright blue background. Discusses theories concerning the apparent fluttering. Suggests doing the trick with a red light-emitting diode in a darkened room. (MVL)

  6. Critical Barriers Phenomenon in Elementary Science.

    ERIC Educational Resources Information Center

    Apelman, Maja; And Others

    Conceptual obstacles which inhibit scientific understanding are examined in this monograph. Perspectives are offered on theoretical aspects, research directions, and educational implications on the problem area known as the critical barriers phenomenon. Papers included are: "Nature of the Problem" (by David Hawkins), which describes the…

  7. Bullying: Description and Analysis of the Phenomenon

    ERIC Educational Resources Information Center

    Benitez, Juan Luis; Justicia, Fernando

    2006-01-01

    This article purports to present this Special Issue about Bullying and, at the same time, to introduce the phenomenon of bullying in order to facilitate readers an updated vision about the problem that will be worked from different perspectives by researchers from national and international scope. With this purpose, we present some controversial…

  8. Feature extraction of arc tracking phenomenon

    NASA Technical Reports Server (NTRS)

    Attia, John Okyere

    1995-01-01

    This document outlines arc tracking signals -- both the data acquisition and signal processing. The objective is to obtain the salient features of the arc tracking phenomenon. As part of the signal processing, the power spectral density is obtained and used in a MATLAB program.

  9. Homocysteine and Raynaud's phenomenon: a review.

    PubMed

    Lazzerini, Pietro Enea; Capecchi, Pier Leopoldo; Bisogno, Stefania; Cozzalupi, Mauro; Rossi, Pier Carlo; Pasini, Franco Laghi

    2010-01-01

    Raynaud's phenomenon, categorized as primary and secondary when occurring isolated or in association with an underlying disease, respectively, is a paroxysmal and recurrent acral ischemia resulting from an abnormal arterial vasospastic response to cold or emotional stress. The key issue in the pathogenesis of Raynaud's phenomenon is presumed to be a dysregulation in the mechanisms of vascular motility resulting in an imbalance between vasodilatation and vasoconstriction. Homocysteine, a non-protein forming sulphured amino acid proposed as an independent risk factor for atherothrombosis in the general population, clearly demonstrated to produce vascular damage through mechanisms also including endothelial injury and modifications in circulating mediators of vasomotion. The rationale for homocysteine involvement in the pathogenesis of Raynaud's phenomenon led some authors to investigate the possible association between mild hyperhomocysteinemia and such a vascular disturbance, particularly in the course of connective tissue disease. Here we review data regarding this putative association and the supposed mechanisms involved, also discussing the emblematic case of a patient with new-onset severe Raynaud's phenomenon and markedly elevated homocysteinemia.

  10. Concept "Medical Museum" as a Sociocultural Phenomenon

    ERIC Educational Resources Information Center

    Chizh, Nina V.; Slyshkin, Gennady G.; Zheltukhina, Marina R.; Privalova, Irina V.; Kravchenko, Olga A.

    2016-01-01

    The article examines the concept "medical museum" as a sociocultural phenomenon. The register of medical museums in Russia makes the material of research. The complex methods of analysis of the concept "medical museum" are used. The philosophical, historical, cultural, structural, communicative and semantic analysis is carried…

  11. Statin escape phenomenon: Fact or fiction?

    PubMed Central

    Barkas, Fotios; Elisaf, Moses; Klouras, Eleftherios; Dimitriou, Theodora; Tentolouris, Nikolaos; Liberopoulos, Evangelos

    2017-01-01

    AIM To evaluate the presence of the so called “statin escape” phenomenon among hyperlipidemic subjects attending a lipid clinic. METHODS This was a retrospective analysis of 1240 hyperlipidemic individuals followed-up for ≥ 3 years. We excluded those individuals meeting one of the following criteria: Use of statin therapy at baseline visit, discontinuation of statin treatment at most recent visit, change in statin treatment during follow-up and poor compliance to treatment. Statin escape phenomenon was defined as an increase in low-density lipoprotein cholesterol (LDL-C) levels at the most recent visit by > 10% compared with the value at 6 mo following initiation of statin treatment. RESULTS Of 181 eligible subjects, 31% exhibited the statin escape phenomenon. No major differences regarding baseline characteristics were found between statin escapers and non-statin escapers. Both escapers and non-escapers had similar baseline LDL-C levels [174 (152-189) and 177 (152-205) mg/dL, respectively]. In comparison with non-escapers, statin escapers demonstrated lower LDL-C levels at 6 mo after treatment initiation [88 (78-97) mg/dL vs 109 (91-129) mg/dL, P < 0.05], but higher levels at the most recent visit [103 (96-118) mg/dL vs 94 (79-114) mg/dL, P < 0.05]. CONCLUSION These data confirm the existence of an escape phenomenon among statin-treated individuals. The clinical significance of this phenomenon remains uncertain. PMID:28261552

  12. A scaling phenomenon in the difference of Shannon information uncertainty of fragments in heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Ma, Chun-Wang; Song, Yi-Dan; Qiao, Chun-Yuan; Wang, Shan-Shan; Wei, Hui-Ling; Ma, Yu-Gang; Cao, Xi-Guang

    2016-08-01

    Shannon information-entropy uncertainty is used to analyze fragments in the measured 140A MeV {}{40,48}Ca + 9Be and {}{58,64}Ni + 9Be reactions. A scaling phenomenon is found in the information-uncertainty difference of fragments between the reactions. The scaling phenomenon is explained in the manner of canonical ensemble theory, and is reproduced in simulated reactions using the antisymmetric molecular dynamics (AMD) and AMD + GEMINI models. The probes based on information uncertainty, requiring no equilibrium state of reaction, can be used in the non-equilibrium system, and bridge the results of the static thermodynamics models and the evolving dynamical transport models.

  13. Single transistor latch phenomenon in junctionless transistors

    NASA Astrophysics Data System (ADS)

    Singh Parihar, Mukta; Ghosh, Dipankar; Kranti, Abhinav

    2013-05-01

    In this work, we report on the single transistor latch phenomenon in junctionless transistors. In the latch condition, the device is unable to turn-off despite a reduction in gate bias. It is shown that impact ionization induced latch condition can occur due to an increase in drain bias, silicon film thickness, gate oxide thickness, and doping concentration. The latch phenomenon is explained in terms of generation-recombination rates, electrostatic potential, electric field distribution and product of current density and electric field (J.E). As latch condition is undesirable for dynamic memory applications, the work highlights the significance of (J.E) as a performance metric to avoid the junctionless transistor being driven into the latch mode.

  14. Introduction to the B[e] Phenomenon

    NASA Astrophysics Data System (ADS)

    Oudmaijer, R. D.; Miroshnichenko, A. S.

    2017-02-01

    In this contribution we introduce the topic of this workshop with a brief history of studies of objects with the B[e] phenomenon, including its discovery and evolution of our understanding of the phenomenon. We will also review the most prominent results on selected objects published prior to the previous B[e] star conference in 2005. These include the discovery of B[e] supergiants in the Magellanic Clouds, detection of maser and laser lines in the spectrum of MWC 349A, studies of η Carinae, and a few more. This talk is planned to set up the stage for discussion of more recent results that will be presented at the conference.

  15. Ringing phenomenon of the fiber ring resonator.

    PubMed

    Ying, Diqing; Ma, Huilian; Jin, Zhonghe

    2007-08-01

    A resonator fiber-optic gyro (R-FOG) is a high-accuracy inertial rotation sensor based on the Sagnac effect. A fiber ring resonator is the core sensing element in the R-FOG. When the frequency of the fiber ring resonator input laser is swept linearly with time, ringing of the output resonance curve is observed. The output field of the fiber ring resonator is derived from the superposition of the light transmitted through the directional coupler directly and the multiple light components circulated in the fiber ring resonator when the frequency of the laser is swept. The amplitude and phase of the output field are analyzed, and it is found that the difference in time for different light components in the fiber ring resonator to reach a point of destructive interference causes the ringing phenomenon. Finally the ringing phenomenon is observed in experiments, and the experimental results agree with the theoretical analysis well.

  16. Diffusion phenomenon in Hilbert spaces and applications

    NASA Astrophysics Data System (ADS)

    Radu, Petronela; Todorova, Grozdena; Yordanov, Borislav

    2011-06-01

    We prove an abstract version of the striking diffusion phenomenon that offers a strong connection between the asymptotic behavior of abstract parabolic and dissipative hyperbolic equations. An important aspect of our approach is that we use in a natural way spectral analysis without involving complicated resolvent estimates. Our proof of the diffusion phenomenon does not use the individual behavior of solutions; instead we show that only their difference matters. We estimate the Hilbert norm of the difference in terms of the Hilbert norm of solutions to the parabolic problems, which allows us to transfer the decay from the parabolic to the hyperbolic problem. The application of these estimates to operators with Markov property combined with a weighted Nash inequality yields explicit and sharp decay rates for hyperbolic problems with variable (x-dependent) coefficients in exterior domains. Our method provides new insight in this area of extensive research which was not well understood until now.

  17. Phase transition phenomenon: A compound measure analysis

    NASA Astrophysics Data System (ADS)

    Kang, Bo Soo; Park, Chanhi; Ryu, Doojin; Song, Wonho

    2015-06-01

    This study investigates the well-documented phenomenon of phase transition in financial markets using combined information from both return and volume changes within short time intervals. We suggest a new measure for the phase transition behaviour of markets, calculated as a return distribution conditional on local variance in volume imbalance, and show that this measure successfully captures phase transition behaviour under various conditions. We analyse the intraday trade and quote dataset from the KOSPI 200 index futures, which includes detailed information on the original order size and the type of each initiating investor. We find that among these two competing factors, the submitted order size yields more explanatory power on the phenomenon of market phase transition than the investor type.

  18. The cutoff phenomenon in finite Markov chains.

    PubMed Central

    Diaconis, P

    1996-01-01

    Natural mixing processes modeled by Markov chains often show a sharp cutoff in their convergence to long-time behavior. This paper presents problems where the cutoff can be proved (card shuffling, the Ehrenfests' urn). It shows that chains with polynomial growth (drunkard's walk) do not show cutoffs. The best general understanding of such cutoffs (high multiplicity of second eigenvalues due to symmetry) is explored. Examples are given where the symmetry is broken but the cutoff phenomenon persists. PMID:11607633

  19. Mechanisms of the warm-up phenomenon.

    PubMed

    Tomai, F; Crea, F; Danesi, A; Perino, M; Gaspardone, A; Ghini, A S; Cascarano, M T; Chiariello, L; Gioffrè, P A

    1996-07-01

    The warm-up phenomenon, described in patients with coronary artery disease, refers to the improved performance following a first exercise test. The aim of this study was to investigate the causes of the warm-up phenomenon. Fifteen patients with coronary artery disease and positive exercise test were enrolled. Patients were off treatment throughout the study. They underwent two consecutive treadmill exercise tests according to the Bruce protocol, with a recovery period of 10 min to re-establish baseline conditions. A third exercise test was then performed 2 h later. Before the onset of ischaemia, the rate-pressure product for a similar degree of workload was similar during the first and second exercise test, while it was lower during the third test (P < 0.05). Time to 1.5 mm ST-segment depression during the second and third exercise test was greater than during the first test (454 +/- 133 and 410 +/- 161 vs 354 +/- 127 s, P < 0.01, respectively). Similarly, the time to anginal pain onset was increased during the second and third exercise tests, compared to the first test (356 +/- 208 and 310 +/- 203 vs 257 +/- 204 s, P < 0.01, respectively). In contrast, rate-pressure product at 1.5 mm ST-segment depression during the second test was higher than that during the first test (232 +/- 47 vs 210 +/- 39 beats.min-1.mmHg.10(2), P < 0.01), while in the third test it was similar to that during the first (209 +/- 43 beats.min-1.mmHg.10(2), P = ns). The warm-up phenomenon observed a few minutes after exercise is characterized by an increase of both time to ischaemia and ischaemic threshold; this adaptation to ischaemia may be due to an improvement of myocardial perfusion or to preconditioning. Conversely, the warm-up phenomenon observed a few hours after repeated exercise is characterized by an increase of time to ischaemia but not of ischaemic threshold and is caused by a slower increase of cardiac workload. Thus, the mechanisms of the warm-up phenomenon may be different

  20. Role of psychiatry in the phenomenon of cults.

    PubMed

    Levine, S V

    1979-11-01

    Religious cults and particularly their attraction for young people are receiving increased attention. There is currently considerable controversy about the role of governmental bodies in understanding and regulating cults and their effect on members. Regardless of their effect on the members of the cult or movement, particularly new members who are often adolescents, membership in a cult produces severe familial tensions. The cult members often develop opinions and modes of behaviour so diametrically different from their families of origin that psychiatrists are often consulted with the view to understand, treat and correct what is seen as behavioural aberration by the families. The phenomenon of religious cults does not seem to be of a passing nature and it is therefore imperative that psychiatrists have a comprehensive and clear a knowledge of the concepts and activities of cults, their seeming effects on young people and their families, and some of the reactions they have caused in society.

  1. Experimental investigations of the ozone zero phenomenon

    NASA Astrophysics Data System (ADS)

    Murayama, K.; Matsumura, N.; Taguchi, M.; Katoh, Y.; Teranishi, K.; Suzuki, S.; Itoh, H.

    2009-08-01

    An experimental study is carried out to clarify the mechanism of the ozone zero phenomenon. Temporal variations of both the discharge characteristics and the metallic electrode surface in the ozone generator are investigated by the Lissajous figure method and Auger electron spectroscopy (AES), respectively. The AES results suggest that a number of oxygen atoms penetrate into the stainless-steel electrode owing to the exposure to ozone. Such a surface change would result in the temporal variation of the discharge characteristics of the generator.

  2. Is iloprost effective in secondary Raynaud's phenomenon?

    PubMed

    Lustig, Nicole; Rada, Gabriel

    2015-03-09

    Patients with systemic sclerosis frequently have Raynaud's phenomenon and digital ischemic ulcers. Iloprost, a synthetic prostacyclin analogue, may be effective in these cases. Searching in Epistemonikos database, which is maintained by screening 20 databases, we identified three systematic reviews including seven randomized trials. We combined the evidence using meta-analysis and generated a summary of findings table following the GRADE approach. We concluded iloprost may lead to little or no difference in the frequency or severity of secondary Raynaud, and it is associated to adverse effects and important costs.

  3. Impact process: an important geological phenomenon.

    PubMed

    Skala, R

    1996-01-01

    The impact process was for a long period of time, even after a wider acceptance among the geological community, considered to be a marginal phenomenon in the Earth sciences. The first decade or two have showed an importance of the process itself and consequent events only too clearly. The present paper is a review describing the history and development of the impact hypothesis, structure and origin of impact craters, influence of huge impacts on the living environment and other aspects of the impact process from the point of view of geology s.l.

  4. Storage-recovery phenomenon in magnonic crystal.

    PubMed

    Chumak, A V; Vasyuchka, V I; Serga, A A; Kostylev, M P; Tiberkevich, V S; Hillebrands, B

    2012-06-22

    The phenomenon of coherent wave trapping and restoration is demonstrated experimentally in a magnonic crystal. Unlike the conventional scheme used in photonics, the trapping occurs not due to the deceleration of the incident wave when it enters the periodic structure but due to excitation of the quasinormal modes of the artificial crystal. This excitation occurs at the group velocity minima of the decelerated wave in narrow frequency regions near the edges of the band gaps of the crystal. The restoration of the traveling wave is implemented by means of phase-sensitive parametric amplification of the stored mode.

  5. Acoustical phenomenon in ancient Totonac's monument

    NASA Astrophysics Data System (ADS)

    Sánchez-Dehesa, José; Ha˚Kansson, Andreas; Cervera, Francisco; Meseguer, Francisco; Manzanares-Martínez, Betsabé; Ramos-Mendieta, Felipe

    2004-05-01

    The circle of gladiators is a monument built by Totonac Indians in the ceremonial site of Cempoala, which is located near Veracruz (Mexico). The city is believed to date to around 1200 A.D. The monument is a round structure with crenellated wall tops, and it has a diameter of 13.4 m. Though the deterioration of this monument is noticeable, it presents a singular acoustical phenomenon whose strength had to be probably extraordinary on the date of its construction. In brief, along any diameter in the circle, one can find two focal points such that if one person speaks on one focus, another person located on the other hears the sound reinforced. In other words, this circular place acoustically behaves as if it were elliptical. Here, we report the experimental characterization of the phenomenon and present a theoretical explanation. Also, the intentionality of the Totonacs is speculated since these people are associated with the Mayan culture, which is known by its realizations of environments with astonishing sonic properties. [Work supported by CEAL-UAM of Spain.

  6. NANOLEAKAGE PHENOMENON ON DEPROTEINIZED HUMAN DENTIN

    PubMed Central

    Duarte, Patrícia de Britto Pereira Garcia; da Silva, Eduardo Moreira

    2007-01-01

    Objective: The purpose of this study was to evaluate the influence of dentin deproteinization on the nanoleakage phenomenon. Material and Methods: Class V cavities were prepared in 12 human molars with cervical margins located in dentin. The cavities were assigned to 2 groups (n=6) according to dentin treatment: Group I - dentin treated in accordance with the manufacturer’s instructions and Group II - dentin treated following the manufacturer’s instructions + 10% NaOCl. Each group was sub-divided into three groups, according to the DBS (dentin bonding system) used: Scotchbond Multi Purpose (SBMP), Prime & Bond NT (PB) and Clearfil SE Bond (SE), which were applied according to manufacturer’s instructions. The cavities were restored with composite resin, and the specimens were immersed in a tracer agent (AgNO3 50%) for 24 h. The teeth were sectioned buccolingually through the center of the restorations, and nanoleakage pattern was evaluated by scanning electron microscopy (SEM) using the backscattered electron image mode. Results: SEM analysis showed different nanoleakage patterns for each DBS. Irrespective of dentin treatments, all SBMP specimens showed nanoleakage. SE did not show any nanoleakage with both dentin treatments used. PB showed nanoleakage within the hybrid layer only in Group I. Conclusions: The influence of dentin deproteinization on the nanoleakage phenomenon was dependent on dentin bonding system formulation and bonding strategies. PMID:19089146

  7. The United States pork niche market phenomenon.

    PubMed

    Honeyman, M S; Pirog, R S; Huber, G H; Lammers, P J; Hermann, J R

    2006-08-01

    After the broad industrialization of the US pork industry, there has been a development of niche markets for export and domestic pork; that is, there is a pork niche market phenomenon. The US pork niche market phenomenon is characterized, and 2 of the major markets are explained in detail. With the Midwest's tradition of a diversified family-based agriculture and record low hog prices of the late 1990s, the conditions were conducive for this phenomenon to develop. Pork niche markets utilize various sales methods including Internet sales, local abattoir sales, direct marketing, farmer networks, and targeting to organized groups. In 2003, there were approximately 35 to 40 active pork niche marketing efforts in Iowa. The Berkshire breed is an example of a swine breed that has had a recent resurgence because of niche markets. Berkshire pork is known for tenderness and excellent quality. Berkshire registrations have increased 4-fold in the last 10 yr. One of the larger niche marketers of "natural pork" is Niman Ranch Pork, which has more than 400 farmer-producers and processes about 2,500 pigs weekly. Many US consumers of pork are interested in issues concerning the environment, food safety, pig welfare, and pig farm ownership and structure. These consumers may be willing to pay more for pork from farmers who are also concerned about these issues. Small- and medium-sized swine farmers are active in pork niche markets. Niche markets claim product differentiation by superior or unique product quality and social attributes. Quality attributes include certain swine breeds, and meat quality, freshness, taste or flavor, and tenderness. Social or credence attributes often are claimed and include freedom from antibiotics and growth promotants; local family farm production; natural, organic, outdoor, or bedded rearing; humane rearing; known origin; environmentally friendly production; and the absence of animal by-products in the feed. Niche pork markets and alternative swine

  8. Anaphylaxis Conundrum: A Trojan Horse Phenomenon.

    PubMed

    Esquivel, Ann; Busse, William W

    Anaphylaxis is a serious and potentially life-threatening allergic reaction that may follow the ingestion of foods. Although these reactions usually follow a common clinical pattern and often demonstrate IgE sensitization to the antigen in question, both the clinical presentation and causative allergen may be atypical, surprising, and difficult to identify. Failure to identify the actual cause of the reaction can compromise treatment and complicate long-term care. Here, we present a patient who had symptoms of anaphylaxis after eating salmon, but confirmation of the causative allergen was not readily apparent. This particular case serves as an insightful lesson for patients undergoing evaluation for anaphylaxis and also provides a framework for navigating through a case involving identification of an underlying allergen.

  9. Dependence phenomenon analysis of the stock market

    NASA Astrophysics Data System (ADS)

    Cheng, Wuyang; Wang, Jun

    2013-04-01

    A random financial stock price model is developed by the interacting contact process, which is one of the statistical-physics systems. The contact process is a continuous-time Markov process, one interpretation of this process is as a model for the spread of an infection, where the epidemic spreading mimics the interplay of local infections and the recovery of individuals. We investigate and analyze the long-term memory, the nonlinear correlations and the multifractal phenomenon of normalized returns of the price model by statistical analysis methods, which include autocorrelation analysis, the Gaussian copula method and the multifractal analysis method. Moreover, we consider the daily returns of the Shanghai Stock Exchange Composite Index and the Shenzhen Stock Exchange Composite Index, and the comparisons of statistical behaviors of returns between the actual data and the simulation data are presented.

  10. No-reflow phenomenon: maintaining vascular integrity.

    PubMed

    Kloner, Robert A

    2011-01-01

    The no-reflow phenomenon relates to the inability to reperfuse regions of the myocardium after ischemia, despite removal of the large epicardial coronary artery occlusion. The mechanism involves microvascular obstruction. In experimental studies, using markers for flow (thioflavin S, carbon black, microspheres), perfusion defects associated with no-reflow demonstrated ultrastructural evidence of localized endothelial swelling and blebs that appeared to obstruct flow. In humans no-reflow is more complicated due to the microemboli of atherosclerotic debris and thrombi generated by percutaneous coronary intervention. The no-reflow zone expands during the first few hours of reperfusion suggesting an element of reperfusion injury. In animal models, extensive no-reflow was associated with worse infarct expansion. The phenomenon of no-reflow following reperfusion therapy for myocardial infarction in humans has been demonstrated by magnetic resonance imaging, echo contrast agents, thallium, technecium-99m-labeled albumin microspheres, Thrombolysis In Myocardial Infarction (TIMI) scores, and myocardial blush grade. Patients exhibiting no-reflow following reperfusion therapy for myocardial infarction have greater left ventricular dilation and remodeling, more congestive heart failure, shock, and reduced survival. Certain vasodilators (adenosine, nitroprusside, nicorandil, and calcium blockers) are used acutely in the catheterization laboratory and appear to improve no-reflow, but systematic studies on therapy for no-reflow are needed. There is now clinical evidence that no-reflow is a strong predictor of long-term mortality that is independent of and beyond that provided by infarct size. Identifying and treating no-reflow may have important benefits including enhancing delivery of nutrients and cells required for healing and reducing infarct expansion and ventricular remodeling, which ultimately may reduce congestive heart failure and mortality.

  11. Epicardial halo phenomenon: a guide for pericardiocentesis?

    PubMed

    Ristić, Arsen D; Wagner, Hans-Joachim; Maksimović, Ružica; Maisch, Bernhard

    2013-05-01

    The epicardial halo delineates the heart shadow in fluoroscopy. To establish whether the sign is applicable to pericardiocentesis guidance, three investigators evaluated its intensity as absent = grade 0, indistinct = 0.5, clear = 1, intensive = 2 in posterior-anterior (PA) and lateral fluoroscopies recorded before pericardiocentesis or cardiac catheterization (Philips Integris-II BH3000). Three populations were studied: (a) 32 patients with pericardial effusion (PE group), 53.1 % males, aged 53.9 ± 13.9 years; (b) 14 patients with perimyocarditis (PM group), 64.3 % males, aged 51.6 ± 14.4 years; and (c) 46 coronary patients (CAD group), no PE, 95.6 % males, aged 67.3 ± 11.8 years. The intensity of the halo phenomenon was highest in patients with PE, lowest in patients with CAD, and intermediate in patients with PM (median sum of grades in PA/lateral view: 4/5 vs. 2/2.5 vs. 3/3, respectively) (p < 0.01). The halo phenomenon correlated well with HR and echocardiographic PE size in both angiographic views. The correlation with body mass index (BMI) and age was significant only in the lateral view and with PE volume only in the PA view. The sensitivity of the halo sign for PE was 84.1 % in PA and 92.0 % in lateral views. In 10/32 PE patients, the evaluation of the sign was repeated after PE drainage, revealing lower grades both in PA and in lateral views (p < 0.01). In conclusion, the epicardial halo sign is highly sensitive for the detection of a PE; it correlates well in at least one angiographic projection with the PE volume, HR, age, BMI, and the PE size in echocardiography and could be therefore applied as a safety guide for pericardiocentesis.

  12. Acoustic characterization of flame blowout phenomenon

    NASA Astrophysics Data System (ADS)

    Nair, Suraj

    Combustor blowout is a very serious concern in modern land-based and aircraft engine combustors. The ability to sense blowout precursors can provide significant payoffs in engine reliability and life. The objective of this work is to characterize the blowout phenomenon and develop a sensing methodology which can detect and assess the proximity of a combustor to blowout by monitoring its acoustic signature, thus providing early warning before the actual blowout of the combustor. The first part of the work examines the blowout phenomenon in a piloted jet burner. As blowout was approached, the flame detached from one side of the burner and showed increased flame tip fluctuations, resulting in an increase in low frequency acoustics. Work was then focused on swirling combustion systems. Close to blowout, localized extinction/re-ignition events were observed, which manifested as bursts in the acoustic signal. These events increased in number and duration as the combustor approached blowout, resulting an increase in low frequency acoustics. A variety of spectral, wavelet and thresholding based approaches were developed to detect precursors to blowout. The third part of the study focused on a bluff body burner. It characterized the underlying flame dynamics near blowout in greater detail and related it to the observed acoustic emissions. Vorticity was found to play a significant role in the flame dynamics. The flame passed through two distinct stages prior to blowout. The first was associated with momentary strain levels that exceed the flame's extinction strain rate, leading to flame "holes". The second was due to large scale alteration of the fluid dynamics in the bluff body wake, leading to violent flapping of the flame front and even larger straining of the flame. This led to low frequency acoustic oscillations, of the order of von Karman vortex shedding. This manifested as an abrupt increase in combustion noise spectra at 40-100 Hz very close to blowout. Finally, work

  13. [Phenomenon of polyembryony. Genetic heterogeneity of seeds].

    PubMed

    Batygina, T B; Vinogradova, G Iu

    2007-01-01

    Different concepts of polyembryony and genetic heterogeneity of seeds in flower plants have been reviewed. Different types, ways, and forms of plant reproduction appeared in the course of evolution as a consequences of the attached mode of life and autotrophy. This is ascribed to totipotency, "stemminess" of plant cells, and presence of constantly functioning meristems, which determined to a great extent the system of plant safety. There are two ways of formation of a new individual: sexual process --> gamospermy involving meiosis and gamete fusion and asexual process --> agamospermy without meiosis and gamete fusion and two types of reproduction: seed and vegetative. Both processes may take place simultaneously in one seed, as a result of which many embryos of different origins are formed: uniparental and biparental inheritance. Traditionally, this phenomenon is called polyembryony. It comprises embryoidogeny (a new category of vegetative reproduction): formation of somatic embryos (= embryoids) in the flower, seed, and on vegetative organs. Genetic heterogeneity is one of the most important characteristics of seeds, which is based on different phenomena, such as embryogeny, embryoidogeny, and gametophytic and sporophytic apomixes. When describing two types of polyembryony, sporophytic (nucellar, integumental, cleavage) and gametophytic (synergidal, antipodal), a great attention is paid to characterization of initial cells of the sexual and adventive embryos. A new concept of apogamety is developed from new positions (totipotency and "stemminess"), which is based on different genesis of cells of the egg and antipodal systems. Five possible pathways of formation of the adventive embryos have been proposed from cells of the egg apparatus. Specific features of the formation of adventive embryos in the case of gametophytic apomixis, such as androgenesis and semigamy, are discussed. Morphogenesis of the sexual and adventive embryos proceeds in the mother organism and

  14. [Phenomenon of super-longevity in Yakutia].

    PubMed

    Tatarinova, O V; Kylbanova, E S; Neustroeva, V N; Semenova, A N; Nikitin, Iu P

    2008-01-01

    According to preliminary data of UNESCO the oldest inhabitant of a planet now lives in the Republic Sakha (Yakutia). The article presents some results of the examination of a 117-years long-liver Semennikova (Djakonova) Varvara Konstantinovna. The age of the supercentenarian is certified by the record in the metric book of Yakutsk Spiritual Consistory for the Bulunskiy Spasskiy Church. The standard methods and unified criteria of estimation applied in epidemiological researches and at examination of elderly contingent were used. The health state, lifestyle and quality of life of the supercentenarian have been studied. During physical and instrumental examination of the centenarian the following data have been obtained: asthenic type of the constitution, the lowered index of body weight; the pathology of organism's functional systems (cardiovascular, respiratory, osteomuscular), appeared in senior age. The basic biochemical parameters of the blood are registered within the limits of the norm. The centenarian almost has not suffered from serious diseases. She does not remember long-livers among her relatives. The phenomenon of supercentenarian in Yakutia is the unique example of the extremely high level of adaptation to the extreme climate with prevailing clinically slightly expressed form.

  15. Opioid antagonists and the sexual satiation phenomenon.

    PubMed

    Rodríguez-Manzo, G; Fernández-Guasti, A

    1995-11-01

    This study evaluates the effects of the IP injection of naloxone (0.3, 3 and 30 mg/kg) and naltrexone (0.2, 2 and 20 mg/kg) on the sexual satiation phenomenon. It was found that both antagonists exert a dose-based biphasic effect on the proportion of sexually exhausted rats displaying copulation. The intermediate doses of both opioid antagonists were more effective than the low and high doses in increasing the percentage of animals engaged in copulation. The analysis of the specific sexual behaviour parameters revealed that naloxone produces a slight inhibitory effect at the lowest dose, evidenced as an increase in the intromission number. The higher doses of this compound facilitated copulation reflected as a shortening of the ejaculation latency and the interintromission interval (III) and an increase in the copulatory rate. Naltrexone treatment had only facilitatory effects at the lower doses by reducing the III. The higher doses of naloxone (3 and 30 mg/kg) and the intermediate dose of naltrexone (2 mg/kg) decreased the spontaneous ambulatory behaviour of sexually satiated rats without impairing sexual behaviour execution. Data suggest a participation of the endogenous opioid systems in the sexual inhibition resulting from sexual exhaustion.

  16. Raynaud's phenomenon: from molecular pathogenesis to therapy.

    PubMed

    Prete, Marcella; Fatone, Maria Celeste; Favoino, Elvira; Perosa, Federico

    2014-06-01

    Raynaud's phenomenon (RP) is a well defined clinical syndrome characterized by recurrent episodes of digital vasospasm triggered by exposure to physical/chemical or emotional stress. RP has been classified as primary or secondary, depending on whether it occurs as an isolated condition (pRP) or is associated to an underlying disease, mainly a connective tissue disease (CTD-RP). In both cases, it manifests with unique "triple" (pallor, cyanosis and erythema), or "double" color changes. pRP is usually a benign condition, while sRP can evolve and be complicated by acral digital ulcers and gangrene, which may require surgical treatment. The pathogenesis of RP has not yet been entirely clarified, nor is it known whether autoantibodies have a role in RP. Even so, recent advances in our understanding of the pathophysiology have highlighted novel potential therapeutic targets. The aim of this review is to discuss the etiology, epidemiology, risk factors, clinical manifestations, recently disclosed pathogenic mechanisms underlying RP and their correlation with the available therapeutic options, focusing primarily on pRP and CTD-RP.

  17. Capillaroscopic pattern in paraneoplastic Raynaud's phenomenon.

    PubMed

    Lambova, S; Müller-Ladner, U

    2013-06-01

    The capillaroscopic pattern in paraneoplastic Raynaud's phenomenon (RP) has not been investigated systematically and is not well-defined. Here, we present three case reports of patients with paraneoplastic rheumatic conditions, manifested with severe secondary RP with emphasis upon capillaroscopic findings. The first patient is a 58-year-old male with known psoriasis and psoriatic arthritis, severe RP and scleroderma-like syndrome, resulting in a paraneoplastic syndrome in the context of a lung cancer. At capillaroscopic examination classic "scleroderma" pattern, an "early" type was found. The second patient is a 48-year-old woman with an abrupt onset of paraneoplastic dermatomyositis, severe RP, and a lung cancer. The capillaroscopic examination revealed frequent dilated and giant capillaries, hemorrhages and severe microvascular disarrangement-the so-called "scleroderma-like" pattern typical of the idiopathic forms of the disease. The third patient is a 56-year-old woman with paraneoplastic dermatomyositis, secondary RP, and thyroid cancer. The capillaroscopic examination showed dilated and giant capillaries, elongated capillaries, decreased mean capillary density with avascular areas, severe disarrangement, single hemorrhages, and clear evidence of neoangiogenesis. These capillaroscopic features characteristic of the "scleroderma-like" pattern are indistinguishable from those in idiopathic dermatomyositis like in the second case. Taken together, the cases illustrate the problem that capillaroscopic patterns in paraneoplastic RP in the context of scleroderma-like syndrome and dermatomyositis appear to be indistinguishable from the microvascular changes in the respective idiopathic rheumatic diseases.

  18. Priming Intelligent Behavior: An Elusive Phenomenon

    PubMed Central

    Shanks, David R.; Newell, Ben R.; Lee, Eun Hee; Balakrishnan, Divya; Ekelund, Lisa; Cenac, Zarus; Kavvadia, Fragkiski; Moore, Christopher

    2013-01-01

    Can behavior be unconsciously primed via the activation of attitudes, stereotypes, or other concepts? A number of studies have suggested that such priming effects can occur, and a prominent illustration is the claim that individuals' accuracy in answering general knowledge questions can be influenced by activating intelligence-related concepts such as professor or soccer hooligan. In 9 experiments with 475 participants we employed the procedures used in these studies, as well as a number of variants of those procedures, in an attempt to obtain this intelligence priming effect. None of the experiments obtained the effect, although financial incentives did boost performance. A Bayesian analysis reveals considerable evidential support for the null hypothesis. The results conform to the pattern typically obtained in word priming experiments in which priming is very narrow in its generalization and unconscious (subliminal) influences, if they occur at all, are extremely short-lived. We encourage others to explore the circumstances in which this phenomenon might be obtained. PMID:23637732

  19. Antimicrobial resistance: a global multifaceted phenomenon

    PubMed Central

    Prestinaci, Francesca; Pezzotti, Patrizio; Pantosti, Annalisa

    2015-01-01

    Antimicrobial resistance (AMR) is one of the most serious global public health threats in this century. The first World Health Organization (WHO) Global report on surveillance of AMR, published in April 2014, collected for the first time data from national and international surveillance networks, showing the extent of this phenomenon in many parts of the world and also the presence of large gaps in the existing surveillance. In this review, we focus on antibacterial resistance (ABR), which represents at the moment the major problem, both for the high rates of resistance observed in bacteria that cause common infections and for the complexity of the consequences of ABR. We describe the health and economic impact of ABR, the principal risk factors for its emergence and, in particular, we illustrate the highlights of four antibiotic-resistant pathogens of global concern – Staphylococcus aureus, Klebsiella pneumoniae, non-typhoidal Salmonella and Mycobacterium tuberculosis – for whom we report resistance data worldwide. Measures to control the emergence and the spread of ABR are presented. PMID:26343252

  20. Anesthesia cutoff phenomenon: Interfacial hydrogen bonding

    SciTech Connect

    Chiou, J.S.; Ma, S.M.; Kamaya, H.; Ueda, I. )

    1990-05-04

    Anesthesia cutoff refers to the phenomenon of loss of anesthetic potency in a homologous series of alkanes and their derivatives when their sizes become too large. In this study, hydrogen bonding of 1-alkanol series (ethanol to eicosanol) to dipalmitoyl-L-alpha-phosphatidylcholine (DPPC) was studied by Fourier transform infrared spectroscopy (FTIR) in DPPC-D2O-in-CCl4 reversed micelles. The alkanols formed hydrogen bonds with the phosphate moiety of DPPC and released the DPPC-bound deuterated water, evidenced by increases in the bound O-H stretching signal of the alkanol-DPPC complex and also in the free O-D stretching band of unbound D2O. These effects increased according to the elongation of the carbon chain of 1-alkanols from ethanol (C2) to 1-decanol (C10), but suddenly almost disappeared at 1-tetradecanol (C14). Anesthetic potencies of these alkanols, estimated by the activity of brine shrimps, were linearly related to hydrogen bond-breaking activities below C10 and agreed with the FTIR data in the cutoff at C10.

  1. Lung tissue mechanics as an emergent phenomenon.

    PubMed

    Suki, Béla; Bates, Jason H T

    2011-04-01

    The mechanical properties of lung parenchymal tissue are both elastic and dissipative, as well as being highly nonlinear. These properties cannot be fully understood, however, in terms of the individual constituents of the tissue. Rather, the mechanical behavior of lung tissue emerges as a macroscopic phenomenon from the interactions of its microscopic components in a way that is neither intuitive nor easily understood. In this review, we first consider the quasi-static mechanical behavior of lung tissue and discuss computational models that show how smooth nonlinear stress-strain behavior can arise through a percolation-like process in which the sequential recruitment of collagen fibers with increasing strain causes them to progressively take over the load-bearing role from elastin. We also show how the concept of percolation can be used to link the pathologic progression of parenchymal disease at the micro scale to physiological symptoms at the macro scale. We then examine the dynamic mechanical behavior of lung tissue, which invokes the notion of tissue resistance. Although usually modeled phenomenologically in terms of collections of springs and dashpots, lung tissue viscoelasticity again can be seen to reflect various types of complex dynamic interactions at the molecular level. Finally, we discuss the inevitability of why lung tissue mechanics need to be complex.

  2. A suspicious reason for Raynaud's phenomenon: Intrauterine device.

    PubMed

    Diken, Adem I; Yalçınkaya, Adnan; Aksoy, Eray; Yılmaz, Seyhan; Çağlı, Kerim

    2015-06-01

    Primary Raynaud's phenomenon may be insistent in patients under medical therapy, and intrauterine devices may be an unnoticed reason in these patients. Fluctuations in female sex hormone status were reported to be associated with the emergence of primary Raynaud's phenomenon symptoms. The use of intrauterine devices was not reported to be associated with Raynaud's phenomenon previously. Intrauterine device may stimulate vascular hyperactivity regarding hormonal or unknown mechanisms that result in Raynaud's phenomenon. We present a postmenopausal patient who complained of primary Raynaud's phenomenon symptoms and had recovery after the removal of her copper intrauterine device.

  3. Acute eosinophilic pneumonia: a hypersensitivity phenomenon?

    PubMed

    Badesch, D B; King, T E; Schwarz, M I

    1989-01-01

    A previously healthy young man presented with acute respiratory distress and diffuse bilateral infiltrates on chest radiograph. Eosinophilic pneumonia was diagnosed by bronchoalveolar lavage and confirmed by transbronchial lung biopsy. There was no evidence of an infectious etiology, and the patient rapidly improved with corticosteroid therapy. Most cases of eosinophilic pneumonia reported previously have followed a chronic course. The case presented here was acute in onset, suggesting a hypersensitivity reaction. High levels of bronchoalveolar lavage eosinophils indicate the diagnosis but not the etiology of eosinophilic pneumonia.

  4. Animal Rights as a Mainstream Phenomenon

    PubMed Central

    Rollin, Bernard E.

    2011-01-01

    Simple Summary The twentieth century has witnessed a bewildering array of ethical revolutions, from civil rights to environmentalism to feminism. Often ignored is the rise of massive societal concern across the world regarding animal treatment. Regulation of animal research exists in virtually all western countries, and reform of “factory farming” is regnant in Europe and rapidly emerging in the United States. Opponents of concern for animals often dismiss the phenomenon as rooted in emotion and extremist lack of appreciation of how unrestricted animal use has improved human life. Such a view totally ignores the rational ethical basis for elevating legal protection for animals, as explained in this essay. Abstract Businesses and professions must stay in accord with social ethics, or risk losing their autonomy. A major social ethical issue that has emerged in the past four decades is the treatment of animals in various areas of human use. Society's moral concern has outgrown the traditional ethic of animal cruelty that began in biblical times and is encoded in the laws of all civilized societies. There are five major reasons for this new social concern, most importantly, the replacement of husbandry-based agriculture with industrial agriculture. This loss of husbandry to industry has threatened the traditional fair contract between humans and animals, and resulted in significant amounts of animal suffering arising on four different fronts. Because such suffering is not occasioned by cruelty, a new ethic for animals was required to express social concerns. Since ethics proceed from preexisting ethics rather than ex nihilo, society has looked to its ethic for humans, appropriately modified, to find moral categories applicable to animals. This concept of legally encoded rights for animals has emerged as a plausible vehicle for reform. PMID:26486217

  5. Binary 193nm photomasks aging phenomenon study

    NASA Astrophysics Data System (ADS)

    Dufaye, Félix; Sartelli, Luca; Pogliani, Carlo; Gough, Stuart; Sundermann, Frank; Miyashita, Hiroyuki; Hidenori, Yoshioka; Charras, Nathalie; Brochard, Christophe; Thivolle, Nicolas

    2011-05-01

    193nm binary photomasks are still used in the semiconductor industry for the lithography of some critical layers for the nodes 90nm and 65nm, with high volumes and over long period. These 193nm binary masks seem to be well-known but recent studies have shown surprising degrading effects, like Electric Field induced chromium Migration (EFM) [1] or chromium migration [2] [3] . Phase shift Masks (PSM) or Opaque MoSi On Glass (OMOG) might not be concerned by these effects [4] [6] under certain conditions. In this paper, we will focus our study on two layers gate and metal lines. We will detail the effects of mask aging, with SEM top view pictures revealing a degraded chromium edge profile and TEM chemical analyses demonstrating the growth of a chromium oxide on the sidewall. SEMCD measurements after volume production indicated a modified CD with respect to initial CD data after manufacture. A regression analysis of these CD measurements shows a radial effect, a die effect and an isolated-dense effect. Mask cleaning effectiveness has also been investigated, with sulphate or ozone cleans, to recover the mask quality in terms of CD. In complement, wafer intrafield CD measurements have been performed on the most sensitive structure to monitor the evolution of the aging effect on mask CD uniformity. Mask CD drift have been correlated with exposure dose drift and isolated-dense bias CD drift on wafers. In the end, we will try to propose a physical explanation of this aging phenomenon and a solution to prevent from it occurring.

  6. Time-Dependent Rate Phenomenon in Viruses

    PubMed Central

    Aiewsakun, Pakorn

    2016-01-01

    ABSTRACT Among the most fundamental questions in viral evolutionary biology are how fast viruses evolve and how evolutionary rates differ among viruses and fluctuate through time. Traditionally, viruses are loosely classed into two groups: slow-evolving DNA viruses and fast-evolving RNA viruses. As viral evolutionary rate estimates become more available, it appears that the rates are negatively correlated with the measurement timescales and that the boundary between the rates of DNA and RNA viruses might not be as clear as previously thought. In this study, we collected 396 viral evolutionary rate estimates across almost all viral genome types and replication strategies, and we examined their rate dynamics. We showed that the time-dependent rate phenomenon exists across multiple levels of viral taxonomy, from the Baltimore classification viral groups to genera. We also showed that, by taking the rate decay dynamics into account, a clear division between the rates of DNA and RNA viruses as well as reverse-transcribing viruses could be recovered. Surprisingly, despite large differences in their biology, our analyses suggested that the rate decay speed is independent of viral types and thus might be useful for better estimation of the evolutionary time scale of any virus. To illustrate this, we used our model to reestimate the evolutionary timescales of extant lentiviruses, which were previously suggested to be very young by standard phylogenetic analyses. Our analyses suggested that these viruses are millions of years old, in agreement with paleovirological evidence, and therefore, for the first time, reconciled molecular analyses of ancient and extant viruses. IMPORTANCE This work provides direct evidence that viral evolutionary rate estimates decay with their measurement timescales and that the rate decay speeds do not differ significantly among viruses despite the vast differences in their molecular features. After adjustment for the rate decay dynamics, the

  7. Powerful Radio Burst Indicates New Astronomical Phenomenon

    NASA Astrophysics Data System (ADS)

    2007-09-01

    Astronomers studying archival data from an Australian radio telescope have discovered a powerful, short-lived burst of radio waves that they say indicates an entirely new type of astronomical phenomenon. Region of Strong Radio Burst Visible-light (negative greyscale) and radio (contours) image of Small Magellanic Cloud and area where burst originated. CREDIT: Lorimer et al., NRAO/AUI/NSF Click on image for high-resolution file ( 114 KB) "This burst appears to have originated from the distant Universe and may have been produced by an exotic event such as the collision of two neutron stars or the death throes of an evaporating black hole," said Duncan Lorimer, Assistant Professor of Physics at West Virginia University (WVU) and the National Radio Astronomy Observatory (NRAO). The research team led by Lorimer consists of Matthew Bailes of Swinburne University in Australia, Maura McLaughlin of WVU and NRAO, David Narkevic of WVU, and Fronefield Crawford of Franklin and Marshall College in Lancaster, Pennsylvania. The astronomers announced their findings in the September 27 issue of the online journal Science Express. The startling discovery came as WVU undergraduate student David Narkevic re-analyzed data from observations of the Small Magellanic Cloud made by the 210-foot Parkes radio telescope in Australia. The data came from a survey of the Magellanic Clouds that included 480 hours of observations. "This survey had sought to discover new pulsars, and the data already had been searched for the type of pulsating signals they produce," Lorimer said. "We re-examined the data, looking for bursts that, unlike the usual ones from pulsars, are not periodic," he added. The survey had covered the Magellanic Clouds, a pair of small galaxies in orbit around our own Milky Way Galaxy. Some 200,000 light-years from Earth, the Magellanic Clouds are prominent features in the Southern sky. Ironically, the new discovery is not part of these galaxies, but rather is much more distant

  8. Reaction profiles in porous electrodes

    NASA Astrophysics Data System (ADS)

    Katan, T.; Carlen, P. J.

    1985-05-01

    An experimental program was conducted to ascertain causes of alkaline zinc electrode shape change and to determine the development of reaction profiles within the pores of porous zinc electrodes. Various analog electrochemical cells were operated to isolate and evaluate the individual processes occurring during charge and discharge. It was found that both edge effects and osmosis can be responsible for the shape change phenomenon.

  9. Recent achievements in the management of Raynaud's phenomenon.

    PubMed

    Baumhäkel, Magnus; Böhm, Michael

    2010-04-15

    Raynaud's phenomenon is a clinical disorder with episodic digital ischemic vasospasm triggered by cold- or emotional-stress. It was first mentioned by Maurice Raynaud in 1862 describing "a local asphyxia of the extremities" and was further divided into primary Raynaud's disease and secondary Raynaud's phenomenon, which is often related to connective tissue diseases, but also physical or chemical strain. Though pathophysiology of Raynaud's phenomenon is still poorly understood, systemic and local vascular effects are most likely to be involved in primary Raynaud's disease. In secondary Raynaud's phenomenon additional abnormalities in vascular structure and function may play the major role. Thus, medical treatment of Raynaud's phenomenon remains unsatisfactory, due to limited understanding of pathophysiological mechanisms. This review addresses current evidence for medical treatment of primary and secondary Raynaud's phenomenon with regard to pathophysiological mechanisms as well as future perspectives.

  10. Raynaud's phenomenon of the nipple associated with labetalol use.

    PubMed

    McGuinness, Naomi; Cording, Vicky

    2013-02-01

    Raynaud's phenomenon of the nipple is an unusual cause of severe nipple pain. Precipitants for Raynaud's phenomenon of the nipple are known to be cold temperatures, caffeine, and emotional stress. Nipple pain is quoted as the most common cause of cessation of breastfeeding. It is important that lactation consultants and other health care professionals are aware of Raynaud's phenomenon of the nipple and the treatment options available. This is a case of a 37-year-old woman, Gravida 2, Para 1, who was first seen in the antenatal clinic at 34 weeks gestation. A diagnosis of Raynaud's phenomenon of the nipple was made after she began taking labetalol for pregnancy-induced hypertension. The phenomenon had occurred in both of her previous pregnancies on commencing labetalol and resolved postnatally on cessation of the drug. We aim to raise awareness of both the condition itself and the potential role of labetalol in the development of Raynaud's phenomenon of the nipple.

  11. Raynaud's phenomenon with oral manifestation in systemic lupus erythematosus.

    PubMed

    da Cunha Bang, F; Lange Wantzin, G; Dahl Christensen, J

    1985-01-01

    A 24-year-old woman with discoid lupus erythematosus developed systemic lupus erythematosus after 6 years. One of the clinical features was Raynaud's phenomenon in the fingers and toes, and furthermore Raynaud's phenomenon appeared in the tongue when exposed to cold and windy weather.

  12. Fluorescence: An Interdisciplinary Phenomenon for Different Education Levels

    ERIC Educational Resources Information Center

    García, J. A.; Moreno, J. M.; Perales, F. J.; Romero, J.; Sánchez, P.; Gómez-Robledo, L.

    2012-01-01

    This paper shows the scientific foundations of a natural phenomenon of undoubted interest and applicability in our day, fluorescence, and its possibilities for teaching at three educational levels: primary, secondary and university. It begins by describing the nature of the phenomenon and continues by explaining how we work with students of the…

  13. The Grey Nomad Phenomenon: Changing the Script of Aging

    ERIC Educational Resources Information Center

    Onyx, Jenny; Leonard, Rosemary

    2007-01-01

    This article explores a relatively new and little understood phenomenon, that of the Australian Grey Nomads. Every year increasing numbers of older Australians take to the road. This article explores the phenomenon both empirically and theoretically. A grounded approach is used by which the experience is explored from an ethnographic account…

  14. Raynaud's phenomenon of the nipples: an elusive diagnosis.

    PubMed

    Morino, Carolyn; Winn, Susan M

    2007-05-01

    Pain and throbbing of the nipples associated with Raynaud's phenomenon often mimics yeast or fungal infections. Breastfeeding mothers with Raynaud's of the nipples are often treated inappropriately for organisms such as Candida Albicans with topical or systemic antifungal agents. This case report describes the eventual diagnosis of Raynaud's phenomenon of the nipples in a breastfeeding mother who was initially treated for yeast.

  15. STUDIES ON THE MECHANISM OF THE SHWARTZMAN PHENOMENON

    PubMed Central

    Stetson, Chandler A.; Good, Robert A.

    1951-01-01

    The inhibition of the Shwartzman phenomenon by nitrogen mustard and benzene has been confirmed and investigated further. This inhibition can be correlated with the leucopenia induced by these agents. Evidence is presented indicating that polymorphonuclear leucocytes play an essential role in the preparation of the skin for the Shwartzman phenomenon. PMID:14803631

  16. [Study on whorl swarming growth phenomenon of Proteus mirabilis].

    PubMed

    He, Xianyuan; Liao, Sixiang; Liu, Junkang; Li, Kun; Liu, Yanxia; Yu, Lurong

    2015-02-01

    The present paper is aimed to explore the origins of Proteus mirabilis (PM) whorl swarming growth phenomenon. The whorl swarming growth phenomenon of PM was observed by changed bacterial culture inoculation time, humidity, vaccination practices, cultured flat placement, magnetic field, pH and other factors. Bacterial ring spiral direction of rotation is counterclockwise and the volatile growth process of PM was whorl swarming growth phenomenon. Spiro fluctuation phenomenon was of high frequency in the sealing tanks by cultured anytime inoculation, wherever inoculation technique applied or not, the presence or absence of the magnetic field, and wherever the dish position was. The experimental results showed that the whorl swarming growth phenomenon of PM requires specific pH environment, in which the facts may be relative to its genetic characteristics and the Earths rotation.

  17. Correction of the Pulfrich phenomenon by surgery and laser.

    PubMed

    Diaper, Charles J M; Heron, Gordon; MacMillan, Ewen S

    2002-02-01

    We describe 2 patients who presented with asymmetrical media changes and a spontaneous Pulfrich phenomenon. In the first case, the phenomenon was due to cataract formation and an interocular latency difference of 1.49 ms +/-0.07 (SD) was found. After cataract surgery, the symptoms resolved and no interocular latency difference could be measured. In the second case, the phenomenon was caused by posterior capsule opacification and an interocular latency difference of 1.16 +/- 0.08 ms was found. The symptoms were alleviated and no interocular latency difference could be measured after a neodymium:YAG laser capsulotomy was performed. The symptomatology of the Pulfrich phenomenon is often difficult for patients to explain. Clinicians should be aware of the phenomenon with cataract patients.

  18. The local dissociation phenomenon in a nitrogen afterglow

    NASA Astrophysics Data System (ADS)

    Levaton, J.; Amorim, J.; Ricard, A.

    2012-12-01

    We used the optical emission spectroscopy diagnostic to study the nitrogen afterglow of a pure N2 flowing dc discharge operating under particular experimental conditions to facilitate the simultaneous occurrence of the pink afterglow (PA) and the Lewis-Rayleigh afterglow. The PA is a special kind of nitrogen plasma occurring outside the direct influence of an external electric field. The phenomenon results from the flux of energy, introduced in the nitrogen molecules by the electrons in the discharge region, from the lower to the higher N_{2}(X\\,^1\\Sigma _g^+ ) vibrational levels due to vibrational-vibrational (V-V) and vibrational-translational (V-T) exchange reactions. We studied the following set of experimental conditions: discharge electric current (I = 15-50 mA), gas pressure (p = 200-1070 Pa) and gas flow rate (Q = 400-1000 sccm). The emissions of the first positive system of the nitrogen molecules were monitored from the end of the discharge down to the end of the post-discharge tube. A kinetic numerical model developed to investigate the nitrogen afterglow generated a calibrating factor for the 580.4 nm band in such a way that the relative density of the N(4S) atoms could be measured along the afterglow. The experimental results indicated that N(4S) atoms are created locally in the afterglow producing atomic density profiles that follow the behaviour of the other species studied experimentally in the PA, such as N_{2}(A\\,^3\\Sigma _u^+ ) , N2(B 3Πg), N2(C 3Πu), N_2^+ (X\\,^2\\Sigma _g^+ ) , N_2^+ (B\\,^2\\Sigma _u^+ ) , N+, N_3^+ , N_4^+ , N(2D) and N(2P). The numerical model was also used to fit the N2(B 3Πg), N_2^+ (B\\,^2\\Sigma _u^+ ) and the N(4S) experimental density profiles and to evaluate the participation of several kinetic pathways capable of producing local dissociation in the N2 afterglow. It was found that the dominant dissociation channel in the PA is the reaction N_2 (a'\\,^1\\Sigma _u^- )+N_2 (X\\,^1\\Sigma _g^+ ,v>4)\\to N(^4S)+N(^4

  19. Effects of oligomerization phenomenon on dissolved organic matter removal kinetics on novel activated carbons.

    PubMed

    Yan, Liang; Deeter, Valerie; Lalley, Jacob; Medellin, Oscar; Kupferle, Margaret J; Sorial, George A

    2014-08-15

    The overall objective of this research was to determine the effects of oxidative coupling (oligomerization) phenomenon on the adsorption kinetics of dissolved natural organic matter (DOM) on novel tailored activated carbons. A comparison of adsorption kinetics data collected in the presence and absence of phenolic compounds under both oxic (presence of molecular oxygen) and anoxic (absence of molecular oxygen) conditions showed that the adsorption rate of DOM was strongly affected by the oligomerization phenomenon. The diffusion rate of DOM is in inverse proportion to the critical oxidation potential of the phenolic compound. In addition, the roles of carbon physicochemical characteristics and DOM molecular weight distribution were also investigated. Tailored activated carbon impregnated with manganese oxide was found to play an important role in promoting complexation reactions between DOM and phenolic compounds. Meanwhile, Fulvic acid molecules (component of DOM) with molecular weight below 2000 Da appeared to have more potential to get influenced from oligomerization effects.

  20. Uhthoff's phenomenon in multiple sclerosis and neuromyelitis optica.

    PubMed

    Park, Kwiyoung; Tanaka, Keiko; Tanaka, Masami

    2014-01-01

    To evaluate and compare the incidence and clinical features of Uhthoff's phenomenon in Japanese patients with neuromyelitis optica (NMO) and those with multiple sclerosis (MS), we asked 135 consecutive patients with MS and an NMO-related disorder (NMOrd) whether they experienced worse neurological symptoms after an increase in body temperature. Responses were obtained from 54 MS and 37 NMOrd patients. Uhthoff's phenomenon was observed in 26 MS (48.1%) and 20 NMOrd patients (54.1%). Motor and sensory symptoms were more frequent than visual symptoms in both diseases. The incidence of Uhthoff's phenomenon was similar in MS and NMOrd.

  1. The Page kidney phenomenon secondary to a traumatic fall.

    PubMed

    Babel, Nitin; Sakpal, Sujit Vijay; Chamberlain, Ronald Scott

    2010-02-01

    Page kidney is a rare phenomenon of hyperreninemic hypertension caused by compression of the renal parenchyma. It has been reported in healthy individuals after blunt abdominal or flank trauma, and in patients after invasive nephrological interventions. We present a case of acute on chronic renal failure and Page kidney phenomenon in an elderly male after a traumatic fall, who underwent effective medical management until spontaneous recovery to baseline was observed. A brief discussion on the Page kidney phenomenon is provided with a suggested algorithmic approach towards the management of this process.

  2. Severe Raynaud's phenomenon-A streamlined approach to acute management.

    PubMed

    Lee, Regent; Lomas, Oliver; Handa, Ashok

    2011-01-01

    Raynaud's phenomenon is an exaggerated vasospastic response to cold or emotional stress which not only may cause the patient severe pain but also critical ischaemia and necrosis of the digits. We report the case of a 69-year-old woman who presented with rest pain, impending ulceration and necrosis of finger tips due to an episode of left-sided Raynaud's phenomenon. Intravenous prostacyclin was administered successfully as a bridge to endoscopic thoracic sympathectomy. Vascular surgery units are ideally positioned for the acute management of severe Raynaud's phenomenon to provide continuity of care to patients with profound digital ischaemia and impending tissue loss.

  3. Glow phenomenon surrounding the vertical stabilizer and OMS pods

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This 35mm frame, photographed as the Space Shuttle Columbia was orbiting Earth during a 'night' pass, documents the glow phenomenon surrounding the vertical stabilizer and the Orbital Maneuvering System (OMS) pods of the spacecraft.

  4. Spontaneous Involution of Congenital Melanocytic Nevus With Halo Phenomenon.

    PubMed

    Lee, Noo Ri; Chung, Hee-Chul; Hong, Hannah; Lee, Jin Wook; Ahn, Sung Ku

    2015-12-01

    Congenital melanocytic nevus (CMN) is a neural crest-derived hamartoma, which appear at or soon after birth. CMN has a dynamic course and may show variable changes over time, including spontaneous involution. Spontaneous involution of CMN is a rare phenomenon and is often reported in association with halo phenomenon or vitiligo. The mechanism of halo phenomenon is yet to be investigated but is suggested to be a destruction of melanocytes by immune responses of cytotoxic T cells or IgM autoantibodies. Here, the authors report an interesting case of spontaneously regressed medium-sized CMN with halo phenomenon and without vitiligo, which provides evidence that cytotoxic T cells account for the halo formation and pigmentary regression of CMN.

  5. Rumpel-Leede phenomenon presenting as a hypertensive urgency.

    PubMed

    Varela, Daniel; Tran, Dat; Ngamdu, Kyari Sumayin; Trullender, Brett; Mukherjee, Debabrata; Abbas, Aamer

    2016-04-01

    Rumpel-Leede (R-L) phenomenon is the rare event in which the small dermal capillaries of an extremity rupture in response to application of a compressive device to that extremity, such as when inflating a cuff during noninvasive blood pressure monitoring or when applying a tourniquet to draw blood. This capillary rupture results in formation of a petechial rash distal to the compressive device. R-L phenomenon is believed to occur most often in patients with underlying vascular disease, such as diabetes mellitus or thrombocytopenia. R-L phenomenon is most often benign, though it may rarely be associated with pain and discomfort. There is no treatment for this condition apart from treatment of the underlying vascular disease or thrombocytopenia. We report a 57-year-old woman who presented with hypertensive urgency and experienced R-L phenomenon during blood pressure cuff inflation.

  6. Prevalence of Raynaud's phenomenon in young Greek males.

    PubMed

    Tzilalis, Vassilios; Panagiotopoulos, Nikolaos; Papatheodorou, George; Rallis, Efstathios; Kassimos, Dimitrios

    2011-01-01

    The aim of this paper is to study the prevalence of Raynaud's phenomenon in young males. Young males were examined prospectively in a district hospital, and laboratory tests were performed on the basis of the clinical history. Young males (3.912), age 18-28 years old, were examined. Raynaud's phenomenon was present in seven men (1,79 per 1.000, 95% CI 0.72-3.68). Three of them had at least one member in their family diagnosed with Raynaud's phenomenon. Three were smokers. All had negative immunological test. Five patients reported having severe attacks and two had only mild ischemic attacks. The treatment was conservative for all patients, two of them necessitated vasodilators. Very low prevalence of Raynaud's phenomenon was observed in this young male group compared with the previous studies.

  7. Post-traumatic Raynaud's phenomenon following volar plate injury.

    PubMed

    Chodakiewitz, Yosef G; Daniels, Alan H; Kamal, Robin N; Weiss, Arnold-Peter C

    2014-04-01

    Post-traumatic Raynaud's phenomenon following non-penetrating or non-repetitive injury is rare. We report a case of Raynaud's phenomenon occurring in a single digit 3 months following volar plate avulsion injury. Daily episodes of painless pallor of the digit occurred for 1 month upon any exposure to cold, resolving with warm water therapy. Symptoms resolved after the initiation of hand therapy, splinting, and range-of- motion exercises.

  8. [Raynaud's phenomenon - first sign of malignancy: case report].

    PubMed

    Sutić, Anamarija; Gračanin, Gudelj; Morović-Vergles, Jadranka

    2014-06-01

    Raynaud's phenomenon is a common phenomenon in the general population. It most commonly occurs in healthy individuals, in whom there is no associated illness or any other cause of Raynaud's phenomenon (primary or idiopathic Raynaud's phenomenon). Secondary Raynaud's phenomenon is common with rheumatic diseases (systemic sclerosis, systemic lupus erythematosus, primary Sjögren's syndrome, mixed connective tissue disease, etc.), occlusive vascular diseases, hematologic disorders, use of vibrating tools and use of some medications, and rarely with malignancy. We report on a patient who presented with a three-week history of painful Raynaud's attacks, which was the reason for seeking assistance of internists in emergency clinic. Upon admission to the hospital and diagnostic work-up, adenocarcinoma of the lung was found. Antinuclear antibodies (ANA), anti-dsDNA antibodies, anticardiolipin IgM and IgG antibodies were present in a lower titer. It is known that rheumatoid factor or ANA characteristic of rheumatic disease are often present in patients with paraneoplastic rheumatic syndromes, which can lead to wrong conclusions about the possible systemic connective tissue diseases and ultimately delay the correct diagnosis. The first appearance of Raynaud's phenomenon as an isolated symptom in people older than 50, with painful signs of ischemia, as in our patient, or the occurrence of asymmetric grasping fingers, especially in men, regardless of the presence of RF, ANA, anti-dsDNA or other autoantibodies, requires broader diagnostic evaluation for malignancy.

  9. Abnormal platelet aggregation in patients with Raynaud's phenomenon.

    PubMed Central

    Biondi, M L; Marasini, B

    1989-01-01

    Platelet aggregation in vitro to several aggregating agents (serotonin (5-HT), adenosine diphosphate, adrenaline and collagen) was studied in 16 patients with primary and secondary Raynaud's phenomenon and compared with that in 13 normal volunteers. Platelets from patients with Raynaud's phenomenon had significantly greater responses to all the 5-HT concentrations tested (p less than 0.001 for 10 microM; p less than 0.01 for 1 microM; p less than 0.05 for 0.1 microM; p less than 0.02 for 0.025 microM) and to low doses of adenosine diphosphate (p less than 0.01 for 1 microM; p less than 0.02 for 0.5 microM) but normal responses to collagen, adrenaline, and high doses of adenosine diphosphate. Patients with secondary Raynaud's phenomenon were significantly more hypersensitive to 0.5 microM adenosine diphosphate than patients with primary Raynaud's phenomenon. In patients with secondary Raynaud's phenomenon there was a significant correlation between the extent of 5-HT aggregation and the duration of the disease. The finding that platelets from patients with Raynaud's phenomenon have enhanced responses to 5-HT and adenosine diphosphate, but normal responses to adrenaline and collagen, is consistent with a role for 5-HT in this disease. PMID:2760232

  10. [Disorders in sodium-water balance].

    PubMed

    Petitclerc, Thierry

    2013-02-01

    Water balance control is aimed at normalizing cellular hydration, and sodium balance control at normalizing extracellular volume. Water balance control is based on the regulation of body fluid tonicity, while the control of sodium balance is based on the regulation of effective arterial volume. Disorders of water balance act on cellular hydration: primary disorders induce a proportional change in tonicity; secondary disorders are induced by a change in tonicity or effective arterial volume. Disorders of sodium balance act on extracellular volume: primary disorders of sodium balance induce a change in effective arterial volume; secondary disorders are induced by a change in effective arterial volume. Physical examination of the patient allows assessing the extracellular volume and the severity of the sodium balance disorder. Natremia - that generally reflects tonicity - allows to assess cellular hydration and to determine the type of water balance disorder. In the case of natremia disturbance, the assessment of both the tonicity and the extracellular volume allows the determination of the type of water and/or sodium balance disorder that is necessary for prescribing the adequate therapy.

  11. Noise Improves Visual Motion Discrimination via a Stochastic Resonance-Like Phenomenon

    PubMed Central

    Treviño, Mario; De la Torre-Valdovinos, Braniff; Manjarrez, Elias

    2016-01-01

    The stochastic resonance (SR) is a phenomenon in which adding a moderate amount of noise can improve the signal-to-noise ratio and performance of non-linear systems. SR occurs in all sensory modalities including the visual system in which noise can enhance contrast detection sensitivity and the perception of ambiguous figures embedded in static scenes. Here, we explored how adding background white pixel-noise to a random dot motion (RDM) stimulus produced changes in visual motion discrimination in healthy human adults. We found that, although the average reaction times (RTs) remained constant, an intermediate level of noise improved the subjects’ ability to discriminate motion direction in the RDM task. The psychophysical responses followed an inverted U-like function of the input noise, whereas the incorrect responses with short RTs did not exhibit such modulation by external noise. Moreover, by applying stimulus and noisy signals to different eyes, we found that the SR phenomenon occurred presumably in the primary visual cortex, where these two signals first converge. Our results suggest that a SR-like phenomenon mediates the improvement of visual motion perception in the RDM task. PMID:27932960

  12. The post-mortem pink teeth phenomenon: a case report.

    PubMed

    Soriano, Evelyne-Pessoa; Carvalho, Marcus-Vitor-Diniz de; Santos, Francisco-Bernardo Dos; Mendoza, Clóvis-César de; Araújo, Maria-do Socorro-Dantas de; Campello, Reginaldo-Inojosa-Carneiro

    2009-07-01

    This study presents the case of the post-mortem pink teeth phenomenon observed during an autopsy procedure performed on the body of a man who was kidnapped and murdered approximately 30 days before the examination. The corpse was in an advanced stage of decomposition and putrefaction. Both maxillary and jaw bones were intact, as well as the permanent teeth which presented the "pink teeth phenomenon", probably due to a haemorrhage in the pulp chambers. The pink discolouration was most pronounced at the neck of the teeth. The cause of death was asphyxia. Although the examiners stressed that post-mortem pink teeth must not be considered as a reliable odontological parameter for determining the cause of death, the results of other studies have shown that the pink teeth phenomenon is a common finding related to cases of asphyxia such as strangulation, drowning or suffocation. Thus, the pink teeth phenomenon must be studied in order to determine its role as a post-mortem finding. As of now, an exact relationship between the cause of death and this phenomenon remains unknown.

  13. Analysis of rewarming curves in Raynaud's phenomenon of various aetiologies.

    PubMed

    Salem, K M; Baker, M; Hilliam, R M; Davies, S; Deighton, C; Bainbridge, L C; Manning, G

    2009-10-01

    This study investigated whether a modified Cold Provocation Test could distinguish between 86 normal subjects and 31 patients with Raynaud's phenomenon or 59 with hand arm vibration syndrome (HAVS). Of the HAVS subjects, 56 were seen for medical reports as they were involved in litigation. Their assessments were done in a different location but the same protocol was used. A standardised cold stress was used to reduce the finger temperature to 15 degrees C or less without inducing reflex hyperaemia. This test had acceptable repeatability for subjects without HAVS with an intra-class correlation of 0.7. Baseline temperature, temperature rise in the first 30 seconds and the time taken to rewarm by 5 degrees C were measured. Patients with Raynaud's phenomenon and HAVS had cooler hands than controls. HAVS patients rewarmed most in the first 30 seconds. Patients with Raynaud's phenomenon take longer to rewarm by 5 degrees C than controls or those with HAVS (P<0.001). A baseline difference of >7.5 degrees C between the temperature of the digit and that of the room is unlikely to occur in patients with Raynaud's phenomenon or HAVS. A temperature gain of > or =2.2 degrees C in the first 30 seconds on rewarming combined with a low baseline temperature strongly suggests HAVS. This modified cold provocation test may differentiate between patients with Raynaud's phenomenon, HAVS and controls but this observation requires independent verification in subjects not involved in litigation and tested in the same facility.

  14. The role of ocean phenomenon in music compositions

    NASA Astrophysics Data System (ADS)

    Liu, Chi-Min

    2016-04-01

    This is a preliminarily interdisciplinary study for exploring the elements of ocean phenomenon appearing in some compositions of classical music. The so-called ocean phenomenon contain wave conditions, climate change, coastal landform, and other natural events around or over the sea. In some music compositions, it is apparent that natural phenomenon over the sea influence the composers' moods and the music pieces they composed. In this poster, some music compositions in the 19th and the early 20th centuries will be introduced to demonstrate the relation between ocean and music works. These works include Meeresstille by Schubert, Étude Op.25 No.12 by Chopin, Fingal's Cave Overture by Mendelssohn, Der Fliegende Holländer by Wagner and La Mer by Debussy. In addition, present idea may give a novel way for music teachers to elucidate the knowledge of ocean science in classes.

  15. Ringing phenomenon based whispering-gallery-mode sensing

    PubMed Central

    Ye, Ming-Yong; Shen, Mei-Xia; Lin, Xiu-Min

    2016-01-01

    Highly sensitive sensing is one of the most important applications of whispering-gallery-mode (WGM) microresonators, which is usually accomplished through a tunable continuous-wave laser sweeping over a whispering-gallery mode with the help of a fiber taper in a relative slow speed. It is known that if a tunable continuous-wave laser sweeps over a high quality whispering-gallery mode in a fast speed, a ringing phenomenon will be observed. The ringing phenomenon in WGM microresonators is mainly used to measure the Q factors and mode-coupling strengths. Here we experimentally demonstrate that the WGM sensing can be achieved based on the ringing phenomenon. This kind of sensing is accomplished in a much shorter time and is immune to the noise caused by the laser wavelength drift. PMID:26796871

  16. Statistical Agent Based Modelization of the Phenomenon of Drug Abuse

    NASA Astrophysics Data System (ADS)

    di Clemente, Riccardo; Pietronero, Luciano

    2012-07-01

    We introduce a statistical agent based model to describe the phenomenon of drug abuse and its dynamical evolution at the individual and global level. The agents are heterogeneous with respect to their intrinsic inclination to drugs, to their budget attitude and social environment. The various levels of drug use were inspired by the professional description of the phenomenon and this permits a direct comparison with all available data. We show that certain elements have a great importance to start the use of drugs, for example the rare events in the personal experiences which permit to overcame the barrier of drug use occasionally. The analysis of how the system reacts to perturbations is very important to understand its key elements and it provides strategies for effective policy making. The present model represents the first step of a realistic description of this phenomenon and can be easily generalized in various directions.

  17. The coronary slow flow phenomenon: a new cardiac "Y" syndrome?

    PubMed

    Leone, Maria Cristina; Gori, Tommaso; Fineschi, Massimo

    2008-01-01

    The coronary slow flow phenomenon (CSFP) is an angiographic finding that is characterised by delayed progression of the contrast medium during coronary angiography. The mechanism of this phenomenon remains unknown. In the present paper, we revise the current evidence regarding this phenomenon and discuss recent findings from our group reporting increased resting resistances in patients with the CSFP. We report that these patients had preserved blood flow responses to the intracoronary infusion of the vasodilator papaverine, demonstrating that the CSFP is not necessarily associated with an abnormal coronary flow reserve. Based on these findings and on the review of the current literature, we concur with the concept proposed by Beltrame et al. that the CSFP should be considered a separate clinical entity. Further studies are necessary to describe the clinical characteristics, including the prognosis, of these patients and to identify potential treatments.

  18. Ringing phenomenon based whispering-gallery-mode sensing

    NASA Astrophysics Data System (ADS)

    Ye, Ming-Yong; Shen, Mei-Xia; Lin, Xiu-Min

    2016-01-01

    Highly sensitive sensing is one of the most important applications of whispering-gallery-mode (WGM) microresonators, which is usually accomplished through a tunable continuous-wave laser sweeping over a whispering-gallery mode with the help of a fiber taper in a relative slow speed. It is known that if a tunable continuous-wave laser sweeps over a high quality whispering-gallery mode in a fast speed, a ringing phenomenon will be observed. The ringing phenomenon in WGM microresonators is mainly used to measure the Q factors and mode-coupling strengths. Here we experimentally demonstrate that the WGM sensing can be achieved based on the ringing phenomenon. This kind of sensing is accomplished in a much shorter time and is immune to the noise caused by the laser wavelength drift.

  19. High prevalence of isolated sleep paralysis: kanashibari phenomenon in Japan.

    PubMed

    Fukuda, K; Miyasita, A; Inugami, M; Ishihara, K

    1987-06-01

    In Japan, a set of experiences called kanashibari is considered identical with isolated sleep paralysis. We investigated this phenomenon by means of a questionnaire administered to 635 college students (390 men and 245 women). Of all subjects, about 40% had experienced at least one episode of kanashibari [subjects of K(+)]. Therefore, isolated sleep paralysis is apparently a more common phenomenon than is usually appreciated. About half of the subjects of K(+) reported that they had been under "physical or psychological stress" or in a "disturbed sleep and wakefulness cycle" immediately before the episode. Many subjects of K(+) experienced the first episode in adolescence. In the distribution of age of first attack, the peak occurred at an earlier age in women subjects than in men subjects. These findings suggest that two factors influence the occurrence of the phenomenon. One is exogenous physical or psychological load and the other is endogenous biological development.

  20. Kernohan's phenomenon associated with left ruptured occipital arteriovenous malformation.

    PubMed

    Fujimoto, A; Sato, H; Katayama, W; Nakai, K; Tsunoda, T; Kobayashi, E; Nose, T

    2004-05-01

    A 23-year-old woman presented with ipsilateral hemiparesia due to rupture of a left occipital arteriovenous malformation (AVM). Emergency decompression (the onset-operation interval was 46 minutes,) was carried out and the patient could leave the hospital upon recovery without neurological deficits. In general, Kernohan's phenomenon is caused by the gradual displacement of the cerebral peduncle against the tentorial edge caused by compression by the contralateral mass. This phenomenon is very rare among the cases with spontaneous intracranial hemorrhage and only three cases including the present one have been reported in the literature. In all cases the onset-operation intervals of were very short. Kernohan's phenomenon associated with a ruptured AVM is a rare condition and emergency decompression is required.

  1. Tears of wine: new insights on an old phenomenon

    PubMed Central

    Venerus, David C.; Nieto Simavilla, David

    2015-01-01

    Anyone who has enjoyed a glass of wine has undoubtedly noticed the regular pattern of liquid beads that fall along the inside of the glass, or ‘tears of wine.’ The phenomenon is the result of a flow against gravity along the liquid film on the glass, which is induced by an interfacial tension gradient. It is generally accepted that the interfacial tension gradient is due to a composition gradient resulting from the evaporation of ethanol. We re-examine the tears of wine phenomenon and investigate the importance of thermal effects, which previously have been ignored. Using a novel experiment and simple model we find that evaporative cooling contributes significantly to the flow responsible for wine tears, and that this phenomenon occurs primarily because of the thermodynamic behavior of ethanol-water mixtures. Also, the regular pattern of tear formation is identified as a well-known hydrodynamic instability. PMID:26548566

  2. Tears of wine: new insights on an old phenomenon

    NASA Astrophysics Data System (ADS)

    Venerus, David C.; Nieto Simavilla, David

    2015-11-01

    Anyone who has enjoyed a glass of wine has undoubtedly noticed the regular pattern of liquid beads that fall along the inside of the glass, or ‘tears of wine.’ The phenomenon is the result of a flow against gravity along the liquid film on the glass, which is induced by an interfacial tension gradient. It is generally accepted that the interfacial tension gradient is due to a composition gradient resulting from the evaporation of ethanol. We re-examine the tears of wine phenomenon and investigate the importance of thermal effects, which previously have been ignored. Using a novel experiment and simple model we find that evaporative cooling contributes significantly to the flow responsible for wine tears, and that this phenomenon occurs primarily because of the thermodynamic behavior of ethanol-water mixtures. Also, the regular pattern of tear formation is identified as a well-known hydrodynamic instability.

  3. [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.

  4. What types of investors generate the two-phase phenomenon?

    NASA Astrophysics Data System (ADS)

    Ryu, Doojin

    2013-12-01

    We examine the two-phase phenomenon described by Plerou, Gopikrishnan, and Stanley (2003) [1] in the KOSPI 200 options market, one of the most liquid options markets in the world. By analysing a unique intraday dataset that contains information about investor type for each trade and quote, we find that the two-phase phenomenon is generated primarily by domestic individual investors, who are generally considered to be uninformed and noisy traders. In contrast, our empirical results indicate that trades by foreign institutions, who are generally considered informed and sophisticated investors, do not exhibit two-phase behaviour.

  5. [Raynaud's phenomenon of the papilla mammae caused by breastfeeding].

    PubMed

    Laursen, Jacob Brink; Rørbye, Christina

    2015-01-26

    In Denmark, the benefits of breastfeeding are emphasized and the Danish Health and Medicines Authority encourages women to breastfeed for at least six months. Raynaud's phenomenon can occur in any small arteriole and cause painful, temporary ischaemia. Women quit breastfeeding prematurely for a variety of reasons, pain being just one of them. In this case report we describe an incident of Raynaud's phenomenon of the nipple and describe how correct diagnosis can prevent unnecessary medical treatment and cause relief of symptoms, thus avoiding premature cessation of breastfeeding.

  6. Binary phenomenon of hope: perceptions of traumatized veterans.

    PubMed

    Levi, Ofir; Liechtentritt, Ronit; Savaya, Riki

    2013-09-01

    This is the second article in a phenomenological study of hope among 10 Israeli reserve soldiers with chronic posttraumatic stress disorder. The aim of the second analysis was to learn about the veterans' conceptualization of hope. The picture of hope that emerges from the analysis of their interviews is of a binary phenomenon in which hope develops but may also be arrested, is conscious but also unconscious, and strengthens the individual but may also weaken one. These findings show the binary phenomenon of hope and how it contributes to coping with traumatic events and therefore can assist professional workers who treat individuals suffering from posttraumatic stress disorder.

  7. [Skin reactions to bradykinin].

    PubMed

    Rihoux, J P; Ramboer, I; Fadel, R

    1995-10-01

    A large series of experiments carried out in animals and humans suggest that histamine release is not involved in the leakage phenomenon induced by bradykinin (BK) challenge. These experiments comprise in vitro studies on skin and bronchial human mast cells and in vivo studies on guinea pig airways and human skin using mepyramine, chlorpheniramine and terfenadine as reference H1-anti-histamines. Nevertheless, it has been shown recently that the H1 antagonist cetirizine 10 mg p.o. markedly inhibits skin reactions induced by BK challenge (intradermal injection of 212 micrograms BK in 10 microL saline and prick test with a solution of 21.2 micrograms/microL). In a guinea pig model, this drug also inhibited the bronchospasm induced by increasing concentrations of BK given by iv route (0.25 to 2 micrograms/Kg) and aerosol (3 to 300 micrograms/Kg). This inhibition was similar to the one obtained with the specific BK antagonist HOE 140 (15 pM/Kg). New data in the literature suggest the existence of various pharmacological mediators possibly involved in the BK-induced reaction: neuromediators, nitric oxyde and PAF. They also suggest that this reaction presents itself as a well defined sequence of pharmacological events. Since we could show that there is no binding of cetirizine to a human recombinant B2 receptor in vitro, some hypotheses are raised in order to explain this unexpected inhibiting effect of cetirizine.

  8. A Modular Approach for Teaching Partial Discharge Phenomenon through Experiment

    ERIC Educational Resources Information Center

    Chatterjee, B.; Dey, D.; Chakravorti, S.

    2011-01-01

    Partial discharge (PD) monitoring is an effective predictive maintenance tool for electrical power equipment. As a result, an understanding of the theory related to PD and the associated measurement techniques is now necessary knowledge for power engineers in their professional life. This paper presents a modular course on PD phenomenon in which…

  9. Experimental Study on Effective Cure of "Tsumari" Phenomenon.

    ERIC Educational Resources Information Center

    Mito, Hiromichi

    1999-01-01

    Examines an effective method of curing tsumari, a phenomenon whereby the first note in a sequence of two eighth-notes is performed shorter than the second note. Considers two possible causes: (1) insufficient motor skill control and (2) a lack of steady beat perception. Reveals a reduction in tsumari after procedural instruction. (CMK)

  10. Exploring Fourier Series and Gibbs Phenomenon Using Mathematica

    ERIC Educational Resources Information Center

    Ghosh, Jonaki B.

    2011-01-01

    This article describes a laboratory module on Fourier series and Gibbs phenomenon which was undertaken by 32 Year 12 students. It shows how the use of CAS played the role of an "amplifier" by making higher level mathematical concepts accessible to students of year 12. Using Mathematica students were able to visualise Fourier series of…

  11. Quantum walk on the line as an interference phenomenon

    SciTech Connect

    Knight, Peter L.; Roldan, Eugenio; Sipe, J. E.

    2003-08-01

    We show that the coined quantum walk on a line can be understood as an interference phenomenon, can be classically implemented, and indeed already has been. The walk is essentially two independent walks associated with the different coin sides, coupled only at initiation. There is a simple analogy between the evolution of walker positions and the propagation of light in a dispersive optical fiber.

  12. Partitioned Image Filtering for Reduction of the Gibbs Phenomenon

    PubMed Central

    Zeng, Gengsheng L.; Allred, Richard J.

    2017-01-01

    The aim of this paper is to propose a partitioned-image filtering technique that is a new way of reducing the Gibbs phenomenon in filtered images. Methods This technique relies on exploiting the properties of the Gibbs phenomenon and on assumptions about the structure of the image. The amplitude of the Gibbs ringing is directly proportional to the height of the image discontinuity. If the height of the discontinuity can be reduced, then the subsequent ringing will also be reduced. Separating the image into stratified layers or partitions reduces the height of the discontinuity significantly. Each partition is filtered separately and recombined nonlinearly to yield the final filtered image. This method weakens filtering of image edges that have large discontinuities, thus reducing the Gibbs phenomenon while simultaneously reducing the image noise. Results The proposed filtering method has been applied to a simple image with only 2 intensity values to illustrate the implementation steps. The method has also been applied to 2 SPECT patient studies to show the effectiveness of the proposed filtering method, which can significantly reduce the Gibbs artifacts. Conclusion The Gibbs phenomenon in a filtered image can be reduced by partitioning the image so that the amplitude of the discontinuity is controlled. The proposed method is efficient and simple in implementation, with fast Fourier transform. PMID:19447854

  13. Observation of a new interference phenomenon in internal conical diffraction.

    PubMed

    Darcy, R T; Lunney, J G; Donegan, J F

    2015-01-26

    Conical diffraction is observed in biaxial materials when a beam of light is directed along one of the two optic axis directions. When the beam is directed close to but not along an optic axis, a rich interference pattern is observed beyond the material. We observe some of the previously predicted low intensity interference patterns, representing a qualitatively new optical phenomenon in biaxial materials.

  14. The Gibbs Phenomenon for Series of Orthogonal Polynomials

    ERIC Educational Resources Information Center

    Fay, T. H.; Kloppers, P. Hendrik

    2006-01-01

    This note considers the four classes of orthogonal polynomials--Chebyshev, Hermite, Laguerre, Legendre--and investigates the Gibbs phenomenon at a jump discontinuity for the corresponding orthogonal polynomial series expansions. The perhaps unexpected thing is that the Gibbs constant that arises for each class of polynomials appears to be the same…

  15. Attachment, Entitlement, and the Impostor Phenomenon in Female Graduate Students

    ERIC Educational Resources Information Center

    Gibson-Beverly, Gina; Schwartz, Jonathan R.

    2008-01-01

    This study examined the utility of attachment and entitlement as predictors of the impostor phenomenon in female graduate students. Findings suggested that individuals with high levels of self-reliance/self-assurance entitlement are able to associate positive feedback with stable internal attributes. Those with anxious attachment and narcissistic…

  16. The Success-Breeds-Success Phenomenon and Bibliometric Processes.

    ERIC Educational Resources Information Center

    Tague, Jean

    1981-01-01

    Describes success-breeds-success phenomenon by single and multiple-urn models, and shows that these models lead to a negative binomial distribution for the total number of successes and to a Zipf-Mandelbrot law for the number of sources contributing a specified number of successes. Ten references are cited. (FM)

  17. A Study of the Impostor Phenomenon among Male Nurse Educators

    ERIC Educational Resources Information Center

    Pierce, Stephanie S.

    2011-01-01

    The Clance Impostor Phenomenon Scale and the Rosenberg Self-Esteem Scale continue to be used to measure impostor characteristics and levels of self-esteem in aggregate populations in corporate and academic environments. Previous studies have focused on females or female dominate populations. A correlational study of nursing educators that are male…

  18. Succession Planning and the Imposter Phenomenon in Higher Education

    ERIC Educational Resources Information Center

    Parkman, Anna; Beard, Roxanne

    2008-01-01

    This article illustrates the impact of the imposter phenomenon on succession planning in higher education, describes imposter behavior in detail and offers a number of strategies to address these behaviors. The authors examine how to reduce the likelihood that an imposter is placed into the succession pipeline and how to reduce imposter behaviors…

  19. The Class Clown Phenomenon Among Middle School Students.

    ERIC Educational Resources Information Center

    Damico, Sandra; Purkey, William

    The purpose of this study was to begin exploration of the "class clown" phenomenon. Eighth grade students identified as class clowns on the basis of multiple peer nominations were compared to a random sample of classmates on: inferred and professed self-concept, school attitude, social status, and classroom behavior. Various demographic…

  20. The Gopniks as a Phenomenon in the Youth Community

    ERIC Educational Resources Information Center

    Gavriliuk, V. V.

    2011-01-01

    The socialization mechanisms of young people in Russia are greatly affected by the prevalence of youth subcultures, both socially positive ones and marginal subcultures that include antisocial ones. In this paper, the author focuses on a phenomenon in the youth community that is quite prevalent in the provinces of Russia, the "gopniki"…

  1. Evaluation of Communication about Groups: The Hydra Phenomenon.

    ERIC Educational Resources Information Center

    Desmond, Roger Jon; Bezzini, John

    A study investigated how the attribution of a problem solution to an individual or group affects the consumer's perception of the solution's quality. Based on the tendency to support group decision-making (Hydra phenomenon) it was predicted that decisions attributed to groups would be perceived as higher in quality than those made by individuals,…

  2. The Splendore-Hoeppli phenomenon in hepatic botryomycosis.

    PubMed Central

    Schlossberg, D; Pandey, M; Reddy, R

    1998-01-01

    A 68 year old diabetic man developed septicaemia and multiple liver abscesses due to Streptococcus intermedius. Liver biopsy revealed streptococcal botryomycosis which showed the Splendore-Hoeppli phenomenon. Diabetes mellitus is an example of the immunosuppressed states that have been associated with botryomycosis. Images PMID:9708210

  3. Erosive gastritis, Armanni-Ebstein phenomenon and diabetic ketoacidosis.

    PubMed

    Byard, Roger W; Zhou, Chong

    2010-12-01

    The Armanni-Ebstein phenomenon, which is found in the kidneys in diabetic ketoacidosis, has also been proposed as an independent diagnostic postmortem marker for hypothermia. A case is reported to demonstrate the possibility of a more complex inter-related etiology in certain instances. A 44-year-old man with a past history of hospital admission for hypothermia, alcoholism and insulin dependent diabetes mellitus was found dead at his home address. At autopsy there were prominent superficial erosive gastritis (Wischnewsky spots) in keeping with terminal hypothermia. In addition there was also marked cortical pallor of the kidneys due to subnuclear renal tubular epithelial vacuolization (Armanni-Ebstein phenomenon). Thus there was evidence for both hypothermia and Armanni-Ebstein phenomenon, suggesting a relationship. Subsequent biochemical testing of vitreous humor, however, demonstrated markedly elevated levels of glucose (36.5 mmol/l; N = 3.6-6.0 mmol/l), β-hydroxybutyrate (23.2 mmol/l; N < 0.3 mmol/l), and lactate (29.4 mmol/l; N = 0.2-2.0 mmol/l). Death was, therefore, due to diabetic ketoacidosis complicated by hypothermia. Diabetes mellitus has a known association with both hypothermia and Armanni-Ebstein phenomenon, thus, before renal tubular vacuolization can be taken as a marker of hypothermia in isolation, it is important to consider the possibility that in certain cases underlying diabetic ketoacidosis may be present.

  4. The E-Book Phenomenon: A Disruptive Technology

    ERIC Educational Resources Information Center

    Wilson, T. D.

    2014-01-01

    Introduction: The e-book and its associated technology have emerged as a disruptive technology over the past ten years. The aim of this paper is to discuss some of the consequences of this development, based on the work of the e-books in Sweden research projects. Argument: To explain the impact of the e-book phenomenon we use Winston's theory of…

  5. Polymorphism of clotting factors in Hungarian patients with Raynaud's phenomenon.

    PubMed

    Shemirani, Amir-Houshang; Szomják, Edit; Balogh, Emese; András, Csilla; Kovács, Dóra; Acs, Judit; Csiki, Zoltán

    2011-01-01

    Patients with primary Raynaud's phenomenon may have a genetically determined risk for clotting factors that predispose them to aberrant microvascular thrombosis. We investigated the prevalence of factor V substitution of G to A at position 1691 (FVLeiden), prothrombin G20210A, and methyltetrahydrofolate reductase C677T mutations in these patients. Two hundred (158 women, 42 men, mean age of 42.4 ± 13.7 years) consecutive patients with primary Raynaud's phenomenon and 200 age-sex-matched healthy controls of Hungarian origin were included in a case-control study. The prevalence of methyltetrahydrofolate reductase C677T homozygous among patients was significantly lower than in the control group (odds ratio 0.4, 95% confidence interval 0.2-0.9, P < 0.05). The prevalence of other thrombosis-associated alleles did not differ between patients with primary Raynaud's phenomenon and control subjects. FVLeiden, prothrombin G20210A, and polymorphism, prothrombin G20210A mutations have no apparent effect on the etiology of primary Raynaud's phenomenon.

  6. Drug Reactions

    MedlinePlus

    Most of the time, medicines make our lives better. They reduce aches and pains, fight infections, and control problems such as high blood pressure or diabetes. But medicines can also cause unwanted reactions. One problem is ...

  7. The hardening phenomenon in irritant contact dermatitis: an interpretative update.

    PubMed

    Watkins, Shannon A; Maibach, Howard I

    2009-03-01

    Irritant contact dermatitis (ICD) is common and poses a significant problem in high-risk populations. In most cases, ICD resolves despite continued exposure in a process known as 'hardening', allowing individuals to continue with their work. Those who cannot clear ICD develop chronic ICD, which is a significant source of emotional, physical, and financial distress for affected individuals. While hardening is well known among labourers and clinicians, its mechanism remains to be elucidated. Much can be learned from the study of self-healing processes like the hardening phenomenon. This overview briefly documents the pathogenesis of ICD, focuses on the latest advances pertaining to the hardening phenomenon in ICD, and then highlights potential avenues of productive research. A better understanding of the 'hardening' process in the skin will hopefully lead to advances for the treatment of ICD.

  8. Decoherence as a Fundamental Phenomenon in Quantum Dynamics

    NASA Astrophysics Data System (ADS)

    Mensky, Michael B.

    The phenomenon of decoherence of a quantum system caused by the entanglement of the system with its environment is discussed from different points of view, particularly in the framework of quantum theory of measurements. The selective presentation of decoherence (taking into account the state of the environment) by restricted path integrals or by effective Schrödinger equation is shown to follow from the first principles or from models. Fundamental character of this phenomenon is demonstrated, particularly the role played in it by information is underlined. It is argued that quantum mechanics becomes logically closed and contains no paradoxes if it is formulated as a theory of open systems with decoherence taken into account. If one insist on considering a completely closed system (the whole Universe), the observer's consciousness has to be included in the theory explicitly. Such a theory is not motivated by physics, but may be interesting as a metaphysical theory clarifying the concept of consciousness.

  9. Inverse-Leidenfrost phenomenon on nanofiber mats on hot surfaces

    NASA Astrophysics Data System (ADS)

    Weickgenannt, Christina M.; Zhang, Yiyun; Sinha-Ray, Suman; Roisman, Ilia V.; Gambaryan-Roisman, Tatiana; Tropea, Cameron; Yarin, Alexander L.

    2011-09-01

    The Leidenfrost effect is a technically and industrially important phenomenon that severely restricts heat removal from high-heat-flux surfaces. A simple remedy to the Leidenfrost effect is provided by polymer nanofiber mats created and deposited by electrospinning on stainless steel surfaces. The influence of nanofiber mats on hydrodynamics and cooling efficiency of single drop impact onto hot surfaces has been investigated experimentally. The evolution of the drops has been recorded by a high-speed complimentary metal-oxide semiconductor camera, whereas the cooling temperature was measured by a thermocouple. A remarkable phenomenon was discovered: a mat of polymer nanofibers electrospun onto a heater surface can completely suppress the Leidenfrost effect, thereby increasing the rate of heat removal from the surface to the liquid drops significantly. The “inverse-Leidenfrost” effect is described qualitatively and quantitatively, providing clear physical reasons for the observed behavior.

  10. Self-Propelled Hovercraft Based on Cold Leidenfrost Phenomenon

    PubMed Central

    Shi, Meng; Ji, Xing; Feng, Shangsheng; Yang, Qingzhen; Lu, Tian Jian; Xu, Feng

    2016-01-01

    The Leidenfrost phenomenon of liquid droplets levitating and dancing when placed upon a hot plate due to propulsion of evaporative vapor has been extended to many self-propelled circumstances. However, such self-propelled Leidenfrost devices commonly need a high temperature for evaporation and a structured solid substrate for directional movements. Here we observed a “cold Leidenfrost phenomenon” when placing a dry ice device on the surface of room temperature water, based on which we developed a controllable self-propelled dry ice hovercraft. Due to the sublimated vapor, the hovercraft could float on water and move in a programmable manner through designed structures. As demonstrations, we showed that the hovercraft could be used as a cargo ship or a petroleum contamination collector without consuming external power. This phenomenon enables a novel way to utilize programmable self-propelled devices on top of room temperature water, holding great potential for applications in energy, chemical engineering and biology. PMID:27338595

  11. Results of an attempt to reproduce the STAP phenomenon

    PubMed Central

    Aizawa, Shinichi

    2016-01-01

    In 2014, Obokata and colleagues reported their observation of a novel cell reprogramming phenomenon they named ‘stimulus-triggered acquisition of pluripotency’ (STAP). The most conclusive evidence for the pluripotency of so-called STAP cells was the purported ability of such cells to contribute to chimera formation. Here, I report the results of an attempt by Haruko Obokata to replicate the phenomenon under the supervision of the Scientific Validity Examination Team of RIKEN. In this follow-up study, putative STAP cells prepared by Haruko Obokata were injected into 1051 embryos, of which 591 were recovered. However, the injected cells made no significant contribution in any of the embryos that developed. PMID:27610221

  12. Historical review of die drool phenomenon during plastics extrusion

    NASA Astrophysics Data System (ADS)

    Musil, Jan; Zatloukal, Martin

    2013-04-01

    Die drool phenomenon is defined as unwanted spontaneous accumulation of extruded polymer melt on open faces of extrusion die during extrusion process. Such accumulated material builds up on the die exit and frequently or continually sticks onto the extruded product and thus damages it. Since die drool appears, extrusion process must be shut down and die exit must be manually cleaned which is time and money consuming. Although die drool is complex phenomenon and its formation mechanism is not fully understood yet, variety of proposed explanations of its formation mechanism and also many ways to its elimination can be found in open literature. Our review presents in historical order breakthrough works in the field of die drool research, shows many ways to suppress it, introduces methods for its quantitative evaluation and composition analysis and summarizes theories of die drool formation mechanism which can be helpful for extrusion experts.

  13. Understanding the alternate bearing phenomenon: Resource budget model

    NASA Astrophysics Data System (ADS)

    Prasad, Awadhesh; Sakai, Kenshi

    2015-12-01

    We consider here the resource budget model of plant energy resources, which characterizes the ecological alternate bearing phenomenon in fruit crops, in which high and low yields occur in alternate years. The resource budget model is a tent-type map, which we study in detail. An infinite number of chaotic bands are observed in this map, which are separated by periodic unstable fixed points. These m bands chaotic attractors become m / 2 bands when the period-m unstable fixed points simultaneously collide with the chaotic bands. The distance between two sets of coexisting chaotic bands that are separated by a period-1 unstable fixed point is discussed. We explore the effects of varying a range of parameters of the model. The presented results explain the characteristic behavior of the alternate bearing estimated from the real field data. Effects of noise are also explored. The significance of these results to ecological perspectives of the alternate bearing phenomenon is highlighted.

  14. Self-Propelled Hovercraft Based on Cold Leidenfrost Phenomenon

    NASA Astrophysics Data System (ADS)

    Shi, Meng; Ji, Xing; Feng, Shangsheng; Yang, Qingzhen; Lu, Tian Jian; Xu, Feng

    2016-06-01

    The Leidenfrost phenomenon of liquid droplets levitating and dancing when placed upon a hot plate due to propulsion of evaporative vapor has been extended to many self-propelled circumstances. However, such self-propelled Leidenfrost devices commonly need a high temperature for evaporation and a structured solid substrate for directional movements. Here we observed a “cold Leidenfrost phenomenon” when placing a dry ice device on the surface of room temperature water, based on which we developed a controllable self-propelled dry ice hovercraft. Due to the sublimated vapor, the hovercraft could float on water and move in a programmable manner through designed structures. As demonstrations, we showed that the hovercraft could be used as a cargo ship or a petroleum contamination collector without consuming external power. This phenomenon enables a novel way to utilize programmable self-propelled devices on top of room temperature water, holding great potential for applications in energy, chemical engineering and biology.

  15. Gravitational Analysis of the In-Band Wormhole Phenomenon

    DTIC Science & Technology

    2006-11-01

    1 GRAVITATIONAL ANALYSIS OF THE IN-BAND WORMHOLE PHENOMENON Richard Gopaul1, Peter Kruus2, Dan Sterne2, Brian Rivera1 1U.S. Army Research...Laboratory Adelphi, MD, 20783 USA 2SPARTA, Inc. Columbia, MD, 21046 USA ABSTRACT In-band wormhole attacks undermine routing by attracting...technique, first presented in [KSG06], for evaluating the effects of in-band wormhole attacks on OLSR routing. The gravitational analysis technique

  16. HIV-associated thromboembolic phenomenon due to protein C deficiency.

    PubMed

    Goyal, Anmol; Shah, Ira

    2014-01-01

    HIV-infected individuals are at a high risk of developing arterial and venous thromboembolism. Opportunistic infections, protease inhibitors, low CD4 count, antiphospholipid antibodies, protein S, and protein C deficiencies are some important risk factors associated with it. However, thromboembolic phenomenon due to protein C deficiency has been rarely reported. We report a case of a 12-year-old girl with facial palsy due to middle cerebral artery infarct because of HIV infection and associated protein C deficiency.

  17. [Phenomenon of visualized concepts in schizophrenic children and adolescents].

    PubMed

    Ledenev, B A; Shevchenko, Iu S

    1987-01-01

    The phenomenon of visualized notions has been studied in 42 children and adolescents with schizophrenia. It has been established that visualized notions, being a peculiar manifestation of the visual image thinking reflecting individual characteristics of the ontogenesis of the psyche, change under the impact of the pathological process, which provides certain clinical information. The assessment of qualitative characteristics and the dynamics of visualized notions in the process of analysis of the mental status may serve as an additional criterion in schizophrenia diagnosis.

  18. Tremor, the cogwheel phenomenon and clonus in Parkinson's disease.

    PubMed

    Findley, L J; Gresty, M A; Halmagyi, G M

    1981-06-01

    Resting and postural tremor, intention and action tremor, clonus and the cogwheel phenomenon in Parkinson's disease have been characterised in terms of frequency content using spectral analysis. Typical resting tremor ranged in peak frequency from 4 to 5.3 HZ with tremor in each individual varying only by 0.2 to 0.3 HZ. The peak frequency of postural tremor ranged between 6 and 6.2 HZ. Intention tremor appeared to be an exaggeration of postural tremor. Clonus evoked by active or passive stretch at the wrist had a frequency of 6 HZ and appeared to be a continuation of postural tremor. The cogwheel phenomenon was found at frequencies between 6 and 6.5 HZ and between 7.5 to 9 HZ. Action tremor was indistinguishable from the cogwheel phenomenon. Some patients had either a symptomatic resting tremor with a concurrent 6 HZ component of smaller amplitude or a symptomatic postural tremor with a 4-5 HZ component of smaller amplitude. These combinations would produce two peaks in the power spectrum. When this occurred EMG studies showed that individual muscles had two types of rhythmical activation suggesting that the tremors have separate mechanisms. Likewise some patients had a symptomatic 6 HZ tremor on posture with a second peak at 8-10 HZ in the physiological band. Therefore, the 6 HZ postural tremor is not an exaggeration of physiological tremor. On the basis of wave form and frequency similarities postural tremor, the low frequency type of active or passive cogwheeling, intention tremor and clonus possibly involve a common spinal mechanism. Higher frequency cogwheel phenomenon and action tremor may be an exaggeration of physiological tremor. More than 80% of patients with Parkinson's disease manifest tremors at both 4-5 HZ and 6 HZ. This combination would appear to be the strongest objective criterion for the diagnosis of basal ganglia disease.

  19. The Will Rogers phenomenon: the effect of different diagnostic criteria.

    PubMed

    Sormani, Maria Pia

    2009-12-01

    The 'Will Rogers phenomenon' is an apparent epidemiological paradox named after a remark made by the humorist Will Rogers about migration during the American economic depression of the 1930's: "When the Okies left Oklahoma and moved to California, they raised the average intelligence level in both states." In 1985, Alvan Feinstein proposed the name 'Will Rogers Phenomenon' to describe the 'stage migration' he observed in patients with cancer. Changes in the criteria for assigning patients to the various stages of a disease can produce spurious improvements in stage-specific prognosis, even though the outcome of individual patients has not changed. In oncology, new imaging tools allowed detection of cancer metastases before they became evident clinically. In consequence, more patients are classified into the more severe metastatic disease stage from the less severe single tumour stage. Such a 'stage migration' resulted in an improved survival of patients in both the less and the more severe disease stages. Multiple sclerosis is also subject to the Will Rogers phenomenon since the introduction of the imaging-assisted McDonald criteria. Given the sensitivity of magnetic resonance imaging for detecting disease activity, which is believed to be five to ten times greater than that of clinical assessment, the McDonald criteria are expected to allow earlier diagnosis, hence the 'stage migration' relative to the previous Poser diagnostic criteria. Because of the ethical problems associated with carrying out placebo-controlled trials in multiple sclerosis owing to the wider availability of therapeutic options, the use of historical controls groups remains an attractive option. However, the Will Rogers phenomenon, which is recognised as one of the most important biases limiting the use of historical controls groups in experimental treatment trials, compromises the interest of this approach. In this context, the use of different diagnostic criteria may generate spurious

  20. Bacterial Programmed Cell Death as a Population Phenomenon

    DTIC Science & Technology

    2013-06-11

    Moving in for the kil:Activation of an endoribonuclease toxin by quorum sensing peptide, Molecular Cell, (03 2011): . doi: 06/11/2013 11.00...shown that E. coli mazEF-mediated cell death is a population phenomenon requiring the E. coli quorum sensing factor EDF (Extracellular Death Factor... quorum - sensing factor required for mazEF-mediated cell death in Escherichia coli. Science 318: 652-655. 7) Kolodkin-Gal I, Engelberg-Kulka, H (2008

  1. The melting phenomenon in random-walk model of DNA

    SciTech Connect

    Hayrapetyan, G. N.; Mamasakhlisov, E. Sh.; Papoyan, Vl. V.; Poghosyan, S. S.

    2012-10-15

    The melting phenomenon in a double-stranded homopolypeptide is considered. The relative distance between the corresponding monomers of two polymer chains is modeled by the two-dimensional random walk on the square lattice. Returns of the random walk to the origin describe the formation of hydrogen bonds between complementary units. To take into account the two competing interactions of monomers inside the chains, we obtain a completely denatured state at finite temperature T{sub c}.

  2. Juvenile dermatomyositis as a paraneoplastic phenomenon: an update.

    PubMed

    Morris, Paula; Dare, Jason

    2010-04-01

    Approximately 33% of adult patients with dermatomyositis develop malignancy with up to 42% presenting after the diagnosis has been made; careful evaluation for malignancy is often undertaken at the time of dermatomyositis diagnosis. This phenomenon has rarely been noted in pediatric patients and extensive workup for malignancy is not indicated in pediatric patients. In 1993, 6 cases were reported in which juvenile dermatomyositis/polymyositis (JDM/PM) appeared to be part of a paraneoplastic phenomenon. Our objective was to update the literature for reported cases of malignancy associated with JDM/PM; we reviewed the literature over the last 15 years and located 6 additional cases. In 9 of 12 reported patients an unusual physical finding such as splenomegaly or lymphadenopathy was noted at the time of diagnosis, and in the entire group, the malignancy occurred within a mean of 12 months. It is less likely that JDM/PM in pediatric patients is a paraneoplastic phenomenon as it is in adult patients. However, if the physical examination at the time of diagnosis of JDM/PM is atypical the presence of malignancy must be considered and a more in-depth evaluation to rule out malignancy should be performed prior to the initiation of treatment.

  3. An allelopathy based model for the Listeria overgrowth phenomenon.

    PubMed

    Fgaier, Hedia; Kalmokoff, Martin; Ells, Timothy; Eberl, Hermann J

    2014-01-01

    In a standard procedure of food safety testing, the presence of the pathogenic bacterium Listeria monocytogenes can be masked by non-pathogenic Listeria. This phenomenon of Listeria overgrowth is not well understood. We present a mathematical model for the growth of a mixed population of L. innocua and L. monocytogenes that includes competition for a common resource and allelopathic control of L. monocytogenes by L. innocua when this resource becomes limited, which has been suggested as one potential explanation for the overgrowth phenomenon. The model is tested quantitatively and qualitatively against experimental data in batch experiments. Our results indicate that the phenomenon of masked pathogens can depend on initial numbers of each population present, and on the intensity of the allelopathic effect. Prompted by the results for the batch setup, we also analyze the model in a hypothetical chemostat setup. Our results suggest that it might be possible to operate a continuous growth environment such that the pathogens outcompete the non-pathogenic species, even in cases where they would be overgrown in a batch environment.

  4. Life as a planetary phenomenon: the colonization of Mars.

    PubMed

    Margulis, L; Guerrero, R

    1995-01-01

    Life is a planet-wide phenomenon in which its components incessantly move and interact. Life imperatively recycles its parts at the surface of the Earth in a chemical transformation and physical transport that depends utterly on the energy from a recent star, the Sun. Humanity, entirely dependent on other beings, plays a recent and relatively small part in the great phenomenon of life that transports and transforms the surface of the Earth. Our species accelerates but does not dominate the metabolism of the Earth system. Ironically, during the Apollo days of the sixties, fears were rampant that Martian or other extraterrestrial "germs" might "contaminate" our planet. After Viking, such fears are seen as the manifestation of cultural paranoia. The Viking missions complemented ground-based astronomical observation and yielded definitive evidence for the lack of life on the red planet. The Gaia hypothesis states that the surface temperature, composition of the reactive gases, oxidation state, alkalinity-acidity on today's Earth are kept homeorrhetically at values set by the sum of the activities of the current biota. Life, in other words, not only produces and maintains its immediate environment, but appears on Earth only as a planetary phenomenon. Since the natural tendency of all life is to grow exponentially to fill proximal volume, the question now "can life ecopoietically expand to Mars?" is entirely equivalent to the query of "can Gaia reproduce?"

  5. Disordered voluntary cough as freezing phenomenon in parkinsonism

    PubMed Central

    Ishii, Mitsuaki; Mashimo, Hideaki

    2017-01-01

    [Purpose] In patients with parkinsonism, the precise mechanism of impaired voluntary cough remains poorly understood. This study used the flow–volume curve to clarify whether disordered voluntary cough reflects the freezing phenomenon. [Subjects and Methods] Case 1 was a 58-year-old female who had been suffering from progressive supranuclear palsy-pure akinesia with gait freezing. Case 2 was a 59-year-old female who had advanced juvenile parkinsonism. The subjects were asked to take a deep inspiration to the total lung capacity and then cough more than five times through the face mask into the spirometer without intervening inspirations between the coughing efforts. [Results] Hesitation in cough initiation (case 2), decreased peak cough flow (case 1), and rounding of the first spike (cases 1 and 2) were observed. In addition, movements of the spike wave at a lower lung volume became progressively smaller and faster (cases 1 and 2). [Conclusion] These clinical manifestations in our patients are similar to those observed in the freezing phenomenon. However, to date, the concept of cough freezing has been underrecognized in clinical practice. From the present study, it could be hypothesized that the freezing phenomenon can occur in voluntary cough as well as in gait, speech, and writing. PMID:28356654

  6. Perspectives of biotechnologies based on dormancy phenomenon for space researches

    NASA Astrophysics Data System (ADS)

    Alekseev, V.; Sychev, V.; Layus, D.; Levinsky, M.; Novikova, N.; Zakhodnova, T.

    Long term space missions will require a renewable source of food and an efficient method to recycle oxygen Plants especially aquatic micro algae provide an obvious solution to these problems However long duration plant growth and reproduction in space that is necessary for transportation of a control ecological life support system CELSS from Earth to other planets are problematic The introduction of heterotrophs in space CELSS is a more formidable problem as the absence of gravity creates additional difficulties for their life Dormancy phenomenon protected a great many animals and plants in harsh environmental conditions within a special resting phases of life cycle lasting from months up to hundred years This phenomenon can be quite perspective as a tool to overcome difficulties with CELSS transportation in space missions Cryptobiotic stages of microbes fungi unicellular algae and protists can survive in open space conditions that is important for interplanetary quarantine and biological security inside spacecraft Searching for life outside the Earth at such planet like Mars with extremely variable environment should be oriented on dormancy as crucial phases of a life cycle in such organisms Five major research programs aimed on study dormancy phenomenon for exobiology purposes and creation of new biotechnologies are discussed List of species candidate components of CELSS with dormancy in their life cycle used in space experiments at the Russian segment of International Space Station now includes 26 species from bacteria to fish The

  7. Life as a planetary phenomenon: the colonization of Mars

    NASA Technical Reports Server (NTRS)

    Margulis, L.; Guerrero, R.

    1995-01-01

    Life is a planet-wide phenomenon in which its components incessantly move and interact. Life imperatively recycles its parts at the surface of the Earth in a chemical transformation and physical transport that depends utterly on the energy from a recent star, the Sun. Humanity, entirely dependent on other beings, plays a recent and relatively small part in the great phenomenon of life that transports and transforms the surface of the Earth. Our species accelerates but does not dominate the metabolism of the Earth system. Ironically, during the Apollo days of the sixties, fears were rampant that Martian or other extraterrestrial "germs" might "contaminate" our planet. After Viking, such fears are seen as the manifestation of cultural paranoia. The Viking missions complemented ground-based astronomical observation and yielded definitive evidence for the lack of life on the red planet. The Gaia hypothesis states that the surface temperature, composition of the reactive gases, oxidation state, alkalinity-acidity on today's Earth are kept homeorrhetically at values set by the sum of the activities of the current biota. Life, in other words, not only produces and maintains its immediate environment, but appears on Earth only as a planetary phenomenon. Since the natural tendency of all life is to grow exponentially to fill proximal volume, the question now "can life ecopoietically expand to Mars?" is entirely equivalent to the query of "can Gaia reproduce?".

  8. Controlling the cavitation phenomenon of evolution on a butterfly valve

    NASA Astrophysics Data System (ADS)

    Baran, G.; Catana, I.; Magheti, I.; Safta, C. A.; Savu, M.

    2010-08-01

    Development of the phenomenon of cavitation in cavitation behavior requires knowledge of both plant and equipment working in the facility. This paper presents a diagram of cavitational behavior for a butterfly valve with a diameter of 100 mm at various openings, which was experimentally built. We proposed seven stages of evolution of the phenomenon of cavitation in the case of a butterfly valve. All these phases are characterized by pressure drop, noise and vibration at various flow rates and flow sections through the valve. The level of noise and vibration for the seven stages of development of the phenomenon of cavitation were measured simultaneously. The experimental measurements were comprised in a knowledge database used in training of a neural network of a neural flow controller that maintains flow rate constantly in the facility by changing the opening butterfly valve. A fuzzy position controller is used to access the valve open. This is the method proposed to provide operational supervision outside the cavitation for a butterfly valve.

  9. Allergic Reactions

    MedlinePlus

    ... that is right for you. In many instances, allergy immunotherapy in the form of shots or tablets is an effective, cost-efficient long term treatment approach. While there is not yet ... Healthy Tips • Allergy symptoms are the result of a chain reaction ...

  10. An interesting case of Lucio phenomenon triggered by activation of hepatitis C infection

    PubMed Central

    Mareen, Jacob; Madhukara, Jithendriya

    2016-01-01

    Lucio phenomenon (LP) or erythema necroticans is a rare type of reaction pattern found in untreated patients with diffuse non-nodular leprosy. It is important to distinguish this from vasculonecrotic erythema nodosum because thalidomide with high-dose steroids is the mainstay of treatment for the latter, whereas LP shows no response to thalidomide. We report a case of a 60-year-old man who presented with purpuric patches, hemorrhagic blisters, and ulcers over extremities of 15 days duration. On cutaneous examination, there were multiple stellate purpuric patches, hemorrhagic bullae, and deep necrotic ulcers, mainly over extremities. Slit-skin smear examination from six sites revealed bacteriological index 6+ with globi, and morphological index 5%. Histopathology revealed diffuse infiltration of bacilli in epidermis, dermis, and endothelial cells along with neutrophilic and lymphocytic infiltrate. Fibrinoid necrosis and thrombosis of blood vessels was also noted. The above clinicohistopathological features helped in making the diagnosis of LP. Concomitantly he was found to be infected with hepatitis C virus. Many triggering factors have been described in literature; however, activation of hepatitis C as a trigger for Lucio phenomenon has not been reported. In addition, IgM and IgG anticardiolipin antibodies were found to be positive. The patient was started on high-dose steroids along with multibacillary antileprosy therapy and improved within 2 weeks. PMID:27730040

  11. Basal cell carcinoma with halo phenomenon in a young female: significance of dermatoscopy in early diagnosis.

    PubMed

    Basak, Pinar Yuksel; Meric, Gonca; Ciris, Metin

    2015-01-01

    Halo phenomenon of nevus may be observed as a circular reaction, although it is unusual around tumors. A 29-year-old woman presented with a pigmented lesion on the cheek since three years. She noted whitening of the skin around the lesion almost after a year following its appearance. Dermatologic examination revealed a pigmented nodular lesion with a hypopigmented halo on the left infraorbital region. The clinical impression was halo nevus, whereas basal cell carcinoma (BCC) was considered in dermatoscopic differential diagnosis. The diagnosis was infiltrative-type BCC histopathologically. The persistence of a perilesional halo around an enlarging pigmented lesion should be carefully examined with accompanying dermatoscopic findings even in young patients for early diagnosis of tumoral lesions.

  12. Splendore-Hoeppli phenomenon in a cat with osteomyelitis caused by Streptococcus species.

    PubMed

    França, Silvia de Araujo; Braga, Juliana Fortes Vilarinho; Moreira, Matheus Vilardo Loes; Silva, Vitor Cesar Martins; Souza, Erick Ferry; Pereira, Luiz Carlos; Rezende, Cleuza Maria de Faria; Ecco, Roselene

    2014-02-01

    A 9-month-old male neutered mixed-breed cat had a history of chronic lameness of the right hind limb, which was non-responsive to antibiotic treatment. Hematologic analysis revealed marked neutrophilia and mild monocytosis. Radiography revealed extensive loss of cortical bone, and replacement with irregular and disorganized bone. There was loss of the normal cortico-medullary distinction, and the medullary cavity had an irregular radiodensity suggestive of osteomyelitis. Surgical curettage and antibiotics did not improve the clinical condition, and amputation was performed. Grossly, the skin over the right tibia was ulcerated with a viscous and granular exudate. At histopathology, there was marked diffuse pyogranulomatous dermatitis, myositis, periostitis and osteomyelitis associated with Splendore-Hoeppli phenomenon. In addition, there was marrow osteoproliferation and multifocal cortical loss, reabsorption, fibroplasia and endosteal bone formation. Gram staining revealed myriad slightly elongated Gram-positive bacteria, arranged in pairs or single chains, confirmed by polymerase chain reaction as Streptococcus species.

  13. Modeling the Pineapple Express phenomenon via Multivariate Extreme Value Theory

    NASA Astrophysics Data System (ADS)

    Weller, G.; Cooley, D. S.

    2011-12-01

    The pineapple express (PE) phenomenon is responsible for producing extreme winter precipitation events in the coastal and mountainous regions of the western United States. Because the PE phenomenon is also associated with warm temperatures, the heavy precipitation and associated snowmelt can cause destructive flooding. In order to study impacts, it is important that regional climate models from NARCCAP are able to reproduce extreme precipitation events produced by PE. We define a daily precipitation quantity which captures the spatial extent and intensity of precipitation events produced by the PE phenomenon. We then use statistical extreme value theory to model the tail dependence of this quantity as seen in an observational data set and each of the six NARCCAP regional models driven by NCEP reanalysis. We find that most NCEP-driven NARCCAP models do exhibit tail dependence between daily model output and observations. Furthermore, we find that not all extreme precipitation events are pineapple express events, as identified by Dettinger et al. (2011). The synoptic-scale atmospheric processes that drive extreme precipitation events produced by PE have only recently begun to be examined. Much of the current work has focused on pattern recognition, rather than quantitative analysis. We use daily mean sea-level pressure (MSLP) fields from NCEP to develop a "pineapple express index" for extreme precipitation, which exhibits tail dependence with our observed precipitation quantity for pineapple express events. We build a statistical model that connects daily precipitation output from the WRFG model, daily MSLP fields from NCEP, and daily observed precipitation in the western US. Finally, we use this model to simulate future observed precipitation based on WRFG output driven by the CCSM model, and our pineapple express index derived from future CCSM output. Our aim is to use this model to develop a better understanding of the frequency and intensity of extreme

  14. Does the dawn phenomenon have clinical relevance in normal pregnancy?

    PubMed Central

    Mandujano, Alicia; Thomas, Alicia; Presley, Larraine Huston; Amini, Saeid B.; de Mouzon, Sylvie Hauguel; Catalano, Patrick M.

    2014-01-01

    OBJECTIVE The dawn phenomenon is a transient rise in blood glucose between 4 and 6 AM that is attributed to the pulsatile release of pituitary growth hormone (GH). In pregnancy, GH is suppressed by placental GH. Hence, we hypothesize that there is no evidence for the dawn phenomenon in late pregnancy in healthy women. STUDY DESIGN Twenty glucose-tolerant women with singleton gestations between 28 weeks and 36 weeks 6 days’ gestation were recruited. The women were admitted overnight to the Clinical Research Unit and had continuous glucose monitoring. Insulin and GH were measured at 2-hour intervals from 8 PM to 8 AM. GH was grouped into times 1A (8–10 PM), 2A (12–2 AM), and 3A (4–8 AM) for changes over time. Further analysis was performed with time 1B (8 PM to 2 AM) and 2B (4–8 AM). Insulin was measured between 4 and 8 AM. RESULTS Plasma glucose decreased over time (P < .001). There were no significant changes in GH among times 1A, 2A, and 3A (P = .45) or times 1B and 2B (P = .12). Insulin concentrations increased after meals, but there were no changes from 4 AM (8.5 ± 1.4 μU/mL) through 8 AM (8.6 ± 1.1 μU/mL; P = .98). CONCLUSION Glucose and insulin concentrations show no increase from 4–8 AM; although there is variability in GH, there is no evidence for the dawn phenomenon in late pregnancy in healthy women. PMID:23583837

  15. Analysis of Ares Crew Launch Vehicle Transonic Alternating Flow Phenomenon

    NASA Technical Reports Server (NTRS)

    Sekula, Martin K.; Piatak, David J.; Rausch, Russ D.

    2012-01-01

    A transonic wind tunnel test of the Ares I-X Rigid Buffet Model (RBM) identified a Mach number regime where unusually large buffet loads are present. A subsequent investigation identified the cause of these loads to be an alternating flow phenomenon at the Crew Module-Service Module junction. The conical design of the Ares I-X Crew Module and the cylindrical design of the Service Module exposes the vehicle to unsteady pressure loads due to the sudden transition between a subsonic separated and a supersonic attached flow about the cone-cylinder junction as the local flow randomly fluctuates back and forth between the two flow states. These fluctuations produce a square-wave like pattern in the pressure time histories resulting in large amplitude, impulsive buffet loads. Subsequent testing of the Ares I RBM found much lower buffet loads since the evolved Ares I design includes an ogive fairing that covers the Crew Module-Service Module junction, thereby making the vehicle less susceptible to the onset of alternating flow. An analysis of the alternating flow separation and attachment phenomenon indicates that the phenomenon is most severe at low angles of attack and exacerbated by the presence of vehicle protuberances. A launch vehicle may experience either a single or, at most, a few impulsive loads since it is constantly accelerating during ascent rather than dwelling at constant flow conditions in a wind tunnel. A comparison of a windtunnel- test-data-derived impulsive load to flight-test-data-derived load indicates a significant over-prediction in the magnitude and duration of the buffet load. I. Introduction One

  16. Luxury perfusion phenomenon in acute herpes simplex virus encephalitis.

    PubMed

    Tanaka, M; Uesugi, M; Igeta, Y; Kondo, S; Sun, X; Hirai, S

    1995-02-01

    In a patient with acute herpes simplex virus (HSV) encephalitis, positron emission tomography (PET) demonstrated increased cerebral blood flow in the affected temporal lobe accompanied by reduction in the cerebral oxygen extraction fraction and the cerebral metabolic rate of oxygen, i.e., luxury perfusion. Follow-up PET studies showed reduction in cerebral perfusion until it was more closely coupled with oxygen metabolism after the resolution of the acute inflammation. These findings support previous single photon emission computed tomographic data and provide a pathophysiological background for the occurrence of hyperperfusion in HSV encephalitis. This is an interesting example of the luxury perfusion phenomenon occurring in a disease other than cerebral ischemia.

  17. Quantum-size resonance tunneling in the field emission phenomenon

    NASA Astrophysics Data System (ADS)

    Litovchenko, V.; Evtukh, A.; Kryuchenko, Yu.; Goncharuk, N.; Yilmazoglu, O.; Mutamba, K.; Hartnagel, H. L.; Pavlidis, D.

    2004-07-01

    Theoretical analyses have been performed of the quantum-size (QS) resonance tunneling in the field-emission (FE) phenomenon for different models of the emitting structures. Such experimentally observed peculiarities have been considered as the enhancement of the FE current, the deviation from the Fowler-Nordheim law, the appearance of sharp current peaks, and a negative resistance. Different types of FE cathodes with QS structures (quantized layers, wires, or dots) have been studied experimentally. Resonance current peaks have been observed, from which the values of the energy-level splitting can be estimated.

  18. The confederate's and others' self-conversion: a neglected phenomenon.

    PubMed

    Laurens, Stéphane; Moscovici, Serge

    2005-04-01

    The authors analyzed a neglected phenomenon: self-conversion. Rather than concentrating on the influence exerted by a confederate on a naive participant, the authors studied how the confederate is himself or herself influenced by the position that he or she defends at the request of the experimenter. This experiment is particularly revealing with respect to a fundamental aspect of the psychology of the proselytizing of minority groups: In the process of convincing others, one also convinces oneself. Exerting influence on others thus leads to self-conversion, which allows the group to reinforce its beliefs and to stand up to conformity pressures.

  19. The B[e] Phenomenon in Symbiotic Binaries

    NASA Astrophysics Data System (ADS)

    Skopal, A.

    2017-02-01

    The spectrum of symbiotic stars (SSs) consists of three basic components of radiation. Two are stellar in nature are produced by the binary components, the evolved cool giant and the hot compact component, whereas the third one is the nebular in nature being rich for emission lines. An additional component from a dust is observed in the near-IR spectrum of the so-called D-type (dusty) SSs. In this contribution I introduce the basic physical processes responsible for the symbiotic phenomenon, model the composite spectrum, and point to a striking similarity of the configuration of B[e] supergiants with that of the hot components during outbursts of SSs.

  20. Surface plasmon resonance phenomenon of the insulating state polyaniline

    SciTech Connect

    Umiati, Ngurah Ayu Ketut; Triyana, Kuwat; Kamsul

    2015-04-16

    Surface Plasmon Resonance (SPR) phenomenon of the insulating polyaniline (PANI) is has been observed. Surface Plasmon (SP) is the traveled electromagnetic wave that passes through the interface of dielectric metal and excited by attenuated total reflection (ATR) method in Kretschmannn configuration (Au-PANI prism). The resonance condition is observed through the angle of SPR in such condition that SP wave is coupled by the evanescent constant of laser beam. In this research, the laser beam was generated by He–Ne and its wavelength (λ) was 632,8 nm. SPR curve is obtained through observation of incidence angles of the laser beam in prism. SPR phenomenon at the boundary between Au – PANI layer has showed by reflection dip when the laser beam passes through the prism. In this early study, the observation was carried out through simulation Winspall 3.02 software and preliminary compared with some experimental data reported in other referred literatures. The results shows that the optimum layer of Au and polyaniline are 50 and 1,5 nm thick respectively. Our own near future experimental work would be further performed and reported elsewhere.

  1. Decoupled Hierarchical Structures for Suppression of Leidenfrost Phenomenon.

    PubMed

    Farokhnia, Nazanin; Sajadi, Seyed Mohammad; Irajizad, Peyman; Ghasemi, Hadi

    2017-03-14

    Thermal management of high temperature systems through cooling droplets is limited by the existence of the Leidenfrost point (LFP), at which the formation of a continuous vapor film between a hot solid and a cooling droplet diminishes the heat transfer rate. This limit results in a bottleneck for the advancement of the wide spectrum of systems including high-temperature power generation, electronics/photonics, reactors, and spacecraft. Despite a long time effort on development of surfaces for suppression of this phenomenon, this limit has only shifted to higher temperatures, but still exists. Here, we report a new multiscale decoupled hierarchical structure that suppress the Leidenfrost state and provide efficient heat dissipation at high temperatures. The architecture of these structures is composed of a nanomembrane assembled on top of a deep micropillar structure. This architecture allows to independently tune the involved forces and to suppress LFP. Once a cooling droplet contacts these surfaces, by rerouting the path of vapor flow, the cooling droplet remains attached to the hot solid substrates even at high temperatures (up to 570 °C) for heat dissipation with no existence of Leidenfrost phenomenon. These new surfaces offer unprecedented heat dissipation capacity at high temperatures (2 orders of magnitude higher than the other state-of-the-art surfaces). We envision that these surfaces open a new avenue in thermal management of high-temperature systems through spray cooling.

  2. Investigation of the Entrainment Phenomenon Using a Scaling Approach

    NASA Astrophysics Data System (ADS)

    Kishore, Aravind; Ghia, Urmila

    2014-11-01

    Air entrainment is a commonly observed phenomenon; we see it when filling a glass with water from a faucet, in the frothing of the ocean surface, in white water rapids, etc. The focus of our work is the numerical simulation of the entrainment phenomenon associated with laminar plunging jets. With increasing jet velocity, the interfacial cusp formed between the jet and the liquid pool becomes sharper. At a critical jet velocity, entrainment inception occurs, i.e., the interfacial cusp breaks, the interface ruptures, and air is pulled into the liquid pool. We conduct two-fluid simulations using the Volume-Of-Fluid (VOF) methodology. The large range of length scales in the flow presents a major computational challenge. We postulate an approach based on scaling of the underlying physics and this helps alleviate the constraints that the physics poses on the numerical method. The approach is validated using a simple flow configuration - a cylinder rotating at an interface between two fluids. Our simulations capture the sharpening of the interfacial cusp, and the sudden rupture of the interface. The predicted critical entrainment velocities are within 1% of experimental data, thereby providing confidence in the approach. This work was supported by the UC Simulation Center at the University of Cincinnati.

  3. Comparative study of analysis methods in biospeckle phenomenon

    NASA Astrophysics Data System (ADS)

    da Silva, Emerson Rodrigo; Muramatsu, Mikiya

    2008-04-01

    In this work we present a review of main statistical properties of speckle patterns and accomplish a comparative study of the more used methods for analysis and extraction of information from optical grainy. The first and second order space-time statistics are dicussed in an overview perspective. The biospeckle phenomenon has detailed attention, specially in its application on monitoring of activity in tissues. The main techniques used to obtain information from speckle patterns are presented, with special prominence to autocorrelation function, co-occurrence matrices, Fujii's method, Briers' contrast and spatial and temporal contrast analisys (LASCA and LASTCA). An incipient method for analysis, based on the study of sucessive correlations contrast, is introduced. Numerical simulations, using diferent probability density functions for velocities of scatterers, were made with two objectives: to test the analysis methods and to give subsidies for interpretation of in vivo results. Vegetable and animal tissues are investigated, achieving the monitoring of senescence process and vascularization maps on leaves, the accompaniment of fungi contamined fruits, the mapping of activity in flowers and the analisys of healing in rats subjected to abdominal surgery. Experiments using the biospeckle phenomenon in microscopy are carried out. At last, it is evaluated the potentiality of biospeckle as diagnosis tool in chronic vein ulcer cared with low intensity laser therapy and the better analysis methods for each kind of tissue are pointed.

  4. Snapshot polarimeter based on the conical refraction phenomenon

    NASA Astrophysics Data System (ADS)

    Peinado, Alba; Lizana, Angel; Turpin, Alex; Estévez, Irene; Iemmi, Claudio; Kalkanjiev, Todor K.; Mompart, Jordi; Campos, Juan

    2015-06-01

    A complete and punctual Stokes polarimeter based on the conical refraction (CR) phenomenon is presented. The CR phenomenon occurs when light travels along one of the optical axes of a biaxial crystal (BC), leading to a bright ring of light at the focal plane of the system. We propose using the connection between the intensity pattern of the CR ring and the state of polarization (SOP) of the incident beam as a new tool for polarization metrology. In order to implement a complete polarimeter, the instrument is designed with a beam splitter and two BCs, one BC for each sub-beam. In the second sub-beam, a retarder is introduced before the BC, allowing us to measure the ellipticity content of the input SOP. The CR-based polarimeter presents several appealing features compared to standard polarimeters. To name some of them, CR polarimeters retrieve the SOP of an input beam with a single snapshot measurement, allow for substantially enhancing the data redundancy without increasing measuring time, and avoid instrumental errors related to rotating elements or active polarization devices. This work shows the instrument design, in particular the parameters of the set-up have been optimized in order to reduce the amplification of noise. Then, the experimental implementation of the instrument is detailed, including the experimental calibration of the system. Finally, the implemented polarimeter is experimentally tested by measuring different SOPs, including fully and partially polarized light.

  5. Focusing phenomenon and near-trapped modes of SH waves

    NASA Astrophysics Data System (ADS)

    Chen, Jeng-Tzong; Lee, Jia-Wei; Tu, Ya-Ching

    2016-09-01

    In this study, the null-field boundary integral equation method (BIEM) and the image method are used to solve the SH wave scattering problem containing semi-circular canyons and circular tunnels. To fully utilize the analytical property of circular geometry, the polar coordinates are used to expand the closed-form fundamental solution to the degenerate kernel, and the Fourier series is also introduced to represent the boundary density. By collocating boundary points to match boundary condition on the boundary, a linear algebraic system is constructed. The unknown coefficients in the algebraic system can be easily determined. In this way, a semi-analytical approach is developed. Following the experience of near-trapped modes in water wave problems of the full plane, the focusing phenomenon and near-trapped modes for the SH wave problem of the half-plane are solved, since the two problems obey the same mathematical model. In this study, it is found that the SH wave problem containing two semi-circular canyons and a circular tunnel has the near-trapped mode and the focusing phenomenon for a special incident angle and wavenumber. In this situation, the amplification factor for the amplitude of displacement is over 300.

  6. [The Will Rogers phenomenon and its impact on imaging diagnostics].

    PubMed

    Golder, W A

    2009-04-01

    The Will Rogers phenomenon is a possible cause of systematic distortions in the results of clinical studies, which can be produced if stage migration occurs during a disease. The term refers to the apparent paradox which is observed when an element is changed from one set to another and the average values of both sets are altered in the same way. The effect is due to the prerequisite that the numerical value of the element being moved is placed between the mean values of both groups. In medicine, this phenomenon is a consequence of the evolution of staging procedures and may be source of misleading statistics for survival in cancer. Both advanced pathological assessment and modern imaging techniques may be involved. The wrong conclusions are induced by comparing the effects of treatment in contemporary patient groups, which profit from extensive diagnostic procedures, to those of historical controls. Treatise informs about the history of the term and illustrates its effects by numerical examples and clinical data. Finally, a model computation based on current PET/CT figures is offered.

  7. a Study of Ricochet Phenomenon for Inclined Impact of Projectile

    NASA Astrophysics Data System (ADS)

    Jo, Jong-Hyun; Lee, Young-Shin

    In this study, the numerical simulation using AUTODYN-3D program was investigated for trajectory prediction for inclined impacts of projectiles. The penetration and perforation of polycarbonate(PC) plate by 7.62 mm projectile was investigated numerically. The characteristic structure of the projectile's trajectory in the PC plates was studied. Two combined failure criteria were used in the target plate, and the target plate was modeled with the properties of polycarbonate for simulating the ricochet phenomenon. The numerical analyses were used to study the effect of the angle of inclination on the trajectory and kinetic energy of the projectile. The dynamic deformation behaviors tests of PC were compared with numerical simulation results which can be used for predictive purpose. Ricochet phenomenon for angles of inclination of 0° ≤ θ ≤ 20° in the analysis. The projectile perforated the plate for θ > 30°, thus defined a failure envelope for numerical configuration. The numerical analyses was used to study the effect under the projectile impact velocity on the depth of penetration(DOP).

  8. Uncertainty quantification applied to the mode coupling phenomenon

    NASA Astrophysics Data System (ADS)

    Treimer, Martin; Allert, Baldur; Dylla, Katrin; Müller, Gerhard

    2017-02-01

    In this study a method for the uncertainty quantification of friction induced vibrations based on the mode coupling phenomenon is shown. The main focus is the assessment of the phenomenon under consideration of uncertain input parameters for the robustness evaluation. Stability assessments of the system under parameter scatter are given. It is pointed out how this is implemented within the scope of the Finite Element method. On the basis of the Euler-Bernoulli beam as a proof-of-concept model a procedure for the assessment of the system's robustness is shown. An objective function is proposed and used to evaluate a design of experiment. By means of a regression analysis an indicator for the robustness of the system is given. Numerical results are presented on the basis of the Euler-Bernoulli beam and a Finite Element brake model. A universal procedure is shown, the approach of which can be used for robustness assessments in different fields of interest. The algorithm that has an optimal efficiency is validated by a comparison with an algorithm which has an optimal quality of prediction. The procedure is applied on the robustness' assessment of brake squeal.

  9. [The knowledge of animal respiration as a combustion phenomenon].

    PubMed

    de Micheli, Alfredo

    2014-01-01

    The different stages leading to knowledge of the phenomenon of animal breathing are going from some writings in Corpus Hippocraticum to Aristoteles' and Galen's works, who considered the heart as the source of the animal heat. Later, Miguel Servet suggested that the inspired air can achieve other functions besides cooling the blood. After that, different explications of the animal heat were raised. About 1770, due to progress of knowledge in the chemistry field, first Mayow and later Black began to consider the animal respiration as a combustion. The important treatise Méthode de nomenclature chimique, published by Guyton de Morveau et al. in 1787 and soon after the Traité élémentaire de chimie de Lavoisier (1789) provided a solid support to Lavoisier's thought. This way on arrived to consider analogous the respiration and combustion phenomena. Studies on the animal respiration phenomenon continued in xix century and in the following century it was possible to apply thermodynamic principles to biology: "generalized thermodynamics".

  10. The McGurk phenomenon in Italian listeners

    PubMed Central

    Bovo, R; Ciorba, A; Prosser, S; Martini, A

    2009-01-01

    Summary In the classic example of the McGurk effect, when subjects see a speaker say /ga/ and hear a simultaneous /ba/, they typically perceive /da/, a syllable that was not presented either acoustically, or visually. This phenomenon, although non-natural and recreated in laboratory investigations, has been studied in order to better understand how, where and when the central nervous system processes and integrates visual and auditory signals. Till now, it has been demonstrated for English, Spanish and German languages, while in Japanese and Chinese it seems weaker. Aim of this study was to evaluate the entity of the McGurk effect for the Italian language. Results obtained demonstrate a robust McGurk effect for the Italian language, which has never been described before. The phenomenon is highly significant when an auditory bilabial Consonant-Vowel is dubbed with a visual apico-dental or velar Consonant-Vowel. Results are discussed on the basis of the recent hypothesis regarding the bimodal perception. PMID:20161878

  11. Investigation of the unstable flow phenomenon in a pump turbine

    NASA Astrophysics Data System (ADS)

    Yin, JunLian; Wang, DeZhong; Walters, D. Keith; Wei, XianZhu

    2014-06-01

    Instability of pump turbine with S-shaped curve is characterized by large fluctuations of rotational speed during the transient processes. For investigating this phenomenon, a numerical model based on the dynamic sliding mesh method (DSSM) is presented and used to numerically solve the 3D transient flow which is characterized by the variable rotation speed of runner. The method is validated by comparison with measured data for a load rejection process in a prototype pump turbine. The results show that the calculated rotation speed agrees well with the experimental data. Based on the validated model, simulations were performed for the runaway process using an artificially assumed operating condition under which the unstable rotation speed is expected to appear. The results confirm that the instability of runner rotational speed can be effectively captured with the proposed method. Presented results include the time history profiles of unit flow rate and unit rotating speed. The internal flow characteristics in a typical unstable period are discussed in detail and the mechanism of the unstable hydraulic phenomenon is explained. Overall, the results suggest that the method presented here can be a viable alternative to predict the dynamic characteristics of pump turbines during transient processes.

  12. Night vision goggle luminance disparity and the Pulfrich phenomenon

    NASA Astrophysics Data System (ADS)

    Pinkus, Alan; Task, Harry L.

    2004-09-01

    When night vision goggle (NVG) image intensifier tubes (I2Ts) are replaced during maintenance, the output luminances of the two channels must not exceed a ratio of 1.5 (brighter channel luminance divided by the dimmer channel luminance) in order to meet the current allowed binocular luminance disparity specification. Two studies were performed to investigate the validity of this requirement. The first study estimated thresholds of binocular luminance disparity detection for observers looking through NVGs. For eight observers, the 25% corrected-for-chance probability of detecting an ocular luminance difference, yielded an average ratio of 1.43 indicating that the current 1.5 specification is perhaps too loose. The second study investigated the Pulfrich phenomenon, a pseudo-stereo effect that can be induced by presenting luminance imbalances to the eyes. This study created NVG luminance imbalances using neutral density (ND) filters and then investigated whether or not the various imbalance levels were sufficient to cause the Pulfrich phenomenon to be perceived. Results indicated an imbalance ratio of 1.10 was insufficient to cause the effect to be seen, but a ratio of 1.26 was sufficient (p <= 0.0003) for the effect to be seen, at least part of the time. Based on these results, it is apparent the allowed binocular luminance disparity ratio should probably be tightened to at least 1.3 with a goal of 1.2.

  13. 25. Ischemic pain in the extremities and Raynaud's phenomenon.

    PubMed

    Devulder, Jacques; van Suijlekom, Hans; van Dongen, Robert; Diwan, Sudhir; Mekhail, Nagy; van Kleef, Maarten; Huygen, Frank

    2011-01-01

    Two important groups of disorders result from an insufficient blood supply to the extremities: critical vascular disease and the Raynaud's phenomenon. The latter can be subdivided into a primary and a secondary type. Critical ischemic disease is often caused by arteriosclerosis due to hypertension or diabetes. Primary Raynaud's is idiopathic and will be diagnosed as such if underlying systemic pathology has been excluded. Secondary Raynaud's is often a manifestation of a systemic disease. It is essential to try to establish a diagnosis as soon as possible in order to influence the evolution of the disease. A sympathetic nerve block can be considered in patients with critical ischemic vascular disease after extensive conservative treatment, preferably in the context of a study (2B±). If this has insufficient effect, spinal cord stimulation can be considered in a selected patient group (2B±). In view of the degree of invasiveness and the costs involved, this treatment should preferably be applied in the context of a study and with the use of transcutaneous pO(2) measurements. In case of primary Raynaud's, life style changes are the first step. Sympathectomy can be considered as a treatment of Raynaud's phenomenon (2C+), but only after multidisciplinary evaluation of the patient and in close consultation with the patient's rheumatologist, vascular surgeon or internist.

  14. The digital divide phenomenon in a hand surgery outpatient clinic.

    PubMed

    Parekh, Selene G; Sodha, Samir; McGuire, Kevin J; Bozentka, David J; Rozental, Tamara D; Beredjiklian, Pedro K

    2004-04-01

    The Internet has become an important source of medical information for patients. However, the availability of this resource for individuals in the lower socioeconomic groups is limited, a concept termed the digital divide. To evaluate this phenomenon, we conducted a survey study to quantify the accessibility and use of the Internet for obtaining medical information in an outpatient hand surgery clinic population. A 28-question survey was distributed to 207 patients concerning computer accessibility, Internet use for medical and nonmedical information, Internet trust and security, and patient economic demographics. After analysis of the data, we found individuals in households with higher incomes had a greater likelihood of owning computers than those in lower income brackets. As income increases, the time spent on the Internet also increases. Another statistically significant trend was that higher income patient households thought that Internet information was trustworthy, secure, and private compared with the lower income brackets. We concluded that clinical settings where the predominant patient population earns less than $18,000 may not benefit or use physician Internet-based services or information. The concept of the digital divide seems to be a real phenomenon in the clinical practice of orthopaedics.

  15. Recognizing and managing the immunologic reactions in leprosy.

    PubMed

    Kamath, Sonia; Vaccaro, Seth A; Rea, Thomas H; Ochoa, Maria T

    2014-10-01

    Immunologic reactions are an important aspect of leprosy that significantly impacts the course of the disease and the associated disability. Reversal reaction (type 1), erythema nodosum leprosum (type 2), and Lucio phenomenon are the 3 leprosy reactions, and they are most commonly seen in patients with the lepromatous and borderline categories of the disease. Because these forms of leprosy are the most common types seen in the United States, it is particularly important for physicians to be able to recognize and treat them. The reactions may occur before, during, or after treatment with multidrug therapy. Reversal reactions are the most common cause of nerve damage in leprosy, and erythema nodosum leprosum may also lead to neuritis. Although there have not been enough studies to confirm the most effective management regimens, treatment of reversal reaction and Lucio phenomenon with prednisone and of erythema nodosum leprosum with thalidomide and/or prednisone may help improve symptoms and prevent further disability.

  16. Poor Sleep Quality Is Associated with Dawn Phenomenon and Impaired Circadian Clock Gene Expression in Subjects with Type 2 Diabetes Mellitus

    PubMed Central

    Li, Yuan; Tao, Xiaoming

    2017-01-01

    Aims. We investigated whether poor sleep quality is associated with both dawn phenomenon and impaired circadian clock gene expression in subjects with diabetes. Methods. 81 subjects with diabetes on continuous glucose monitoring were divided into two groups according to the Pittsburgh Sleep Quality Index. The magnitude of dawn phenomenon was quantified by its increment from nocturnal nadir to prebreakfast. Peripheral leucocytes were sampled from 81 subjects with diabetes and 28 normal controls at 09:00. Transcript levels of circadian clock genes (BMAL1, PER1, PER2, and PER3) were determined by real-time quantitative polymerase chain reaction. Results. The levels of HbA1c and fasting glucose and the magnitude of dawn phenomenon were significantly higher in the diabetes group with poor sleep quality than that with good sleep quality. Peripheral leucocytes from subjects with poor sleep quality expressed significantly lower transcript levels of BMAL1 and PER1 compared with those with good sleep quality. Poor sleep quality was significantly correlated with magnitude of dawn phenomenon. Multiple linear regression showed that sleep quality and PER1 were significantly independently correlated with dawn phenomenon. Conclusions. Dawn phenomenon is associated with sleep quality. Furthermore, mRNA expression of circadian clock genes is dampened in peripheral leucocytes of subjects with poor sleep quality. PMID:28352282

  17. NASA Glenn Research Center Experience with LENR Phenomenon

    NASA Technical Reports Server (NTRS)

    Wrbanek, Susan Y.; Fralick, Gustave C.; Wrbanek, John D.; Niedra, Janis M.

    2012-01-01

    Since 1989 NASA Glenn Research Center (GRC) has performed some small-scale limited experiments that show evidence of effects claimed by some to be evidence of Low Energy Nuclear Reactions (LENR). The research at GRC has involved observations and work on measurement techniques for observing the temperature effects in reactions of isotopes of hydrogen with palladium hydrides. The various experiments performed involved loading Pd with gaseous H2 and D2, and exposing Pd thin films to multi-bubble sonoluminescence in regular and deuterated water. An overview of these experiments and their results will be presented.

  18. NASA Glenn Research Center Experience with "LENR Phenomenon"

    NASA Technical Reports Server (NTRS)

    Wrbanek, Susan Y.; Fralick, Gustave C.; Wrbanek, John D.; Niedra, Janis M.

    2012-01-01

    Since 1989 NASA Glenn Research Center (GRC) has performed some small-scale limited experiments that show evidence of effects claimed by some to be evidence of Low Energy Nuclear Reactions (LENR). The research at GRC has involved observations and work on measurement techniques for observing the temperature effects in reactions of isotopes of hydrogen with palladium hydrides. The various experiments performed involved loading Pd with gaseous H2 and D2, and exposing Pd thin films to multi-bubble sonoluminescence in regular and deuterated water. An overview of these experiments and their results will be presented.

  19. Same-sex marriage: a new social phenomenon.

    PubMed

    Chamie, Joseph; Mirkin, Barry

    2011-01-01

    Same-sex marriage (SSM) is a new social phenomenon. In modern times SSM did not exist until the 21st century when an increasing number of countries began permitting same-sex couples to marry legally. This study presents statistical and related evidence concerning SSM worldwide, with special attention to the United States, where SSM has evolved into a major political and legal issue. In addition to examining data on levels and trends, differentials between men and women are investigated. The study also considers common arguments for and against SSM and likely changes in laws and policies that may occur. Although same-sex marriage now exists in a small number of countries and US states, its consequences and implications are being felt far beyond the borders of those countries and areas. In coming years same-sex marriage will remain a controversial and salient part of the legal, political, and cultural landscape, locally, nationally, and internationally.

  20. Testicular microlithiasis in a unilateral undescended testis: a rare phenomenon.

    PubMed

    Sharma, S; Manchanda, V; Gupta, R

    2013-12-01

    Testicular microlithiasis (TM) is a rare benign condition with presence of multiple small microcalcifications in the seminiferous tubules. Though the aetiology is unknown, TM has been described in association with a variety of urological conditions. We report the clinico-pathological features of a 12-year-old male child who underwent orchidectomy for undescended testis. Histopathological examination of the excised testis showed multiple small intratubular calcifications without any evidence of testicular neoplasia. TM is an unusual phenomenon that should be kept in mind while evaluating testicular biopsies. Though it behaves in a benign manner in most of the cases, patients with positive family history of testicular cancer should be followed-up for testicular tumour.

  1. The Takete-Maluma phenomenon in autism spectrum disorders.

    PubMed

    Occelli, Valeria; Esposito, Gianluca; Venuti, Paola; Arduino, Giuseppe Maurizio; Zampini, Massimiliano

    2013-01-01

    It has been reported that people tend to preferentially associate phonemes like /m/, /l/, /n/ to curvilinear shapes and phonemes like /t/, /z/, /r/, /k/ to rectilinear shapes. Here we evaluated the performance of children/adolescents with autism spectrum disorders (ASD) and neurotypical controls in this audiovisual congruency phenomenon. Pairs of visual patterns (curvilinear vs rectilinear) were presented to a group of ASD participants (low- or high-functioning) and a group of age-matched neurotypical controls. Participants were asked to associate each item to non-meaningful phoneme clusters. ASD participants showed a lower proportion of expected association responses than the controls. Within the ASD group the performance varied as a function of the severity of the symptomatology. These data suggest that children/adolescents with ASD show, although at different degrees as a function of the severity of the ASD, lower phonetic-iconic congruency response patterns than neurotypical controls, pointing to poorer multisensory integration capabilities.

  2. Violence against women: the phenomenon of workplace violence against nurses.

    PubMed

    Child, R J Howerton; Mentes, Janet C

    2010-02-01

    Registered nurses have been the recipients of an alarming increase in workplace violence (WPV). Emergency and psychiatric nurses have been found to be the most vulnerable and yet few solid reporting procedures exist to fully account for a true number of incidents. Further compounding the problem is the lack of a standard definition of violence to guide reporting procedures, interventions, legislation, and research. While there are certain risk factors that not only predispose the nurse and the patient to WPV, research continues to attempt to parse out which risk factors are the key determinants of WPV and also which interventions prove to be significant in reducing WPV. The nursing shortage is expected only to increase; recruitment and retention of qualified staff members may be deterred by WPV. This necessitates focused research on the phenomenon of workplace violence in health care.

  3. Child maltreatment as a global phenomenon: from trauma to prevention.

    PubMed

    Cyr, Chantal; Michel, Geneviève; Dumais, Marilyne

    2013-01-01

    Past studies have clearly showed the negative impact of neglect and abuse on child development at both the psychological and neurobiological levels. To date, many studies have focused on identifying risk and protective factors occurring at all levels of the ecology. However, more distal-level variables, such as culture and ethnicity, have not been studied as much as those of more proximal levels; yet studies in Western countries have consistently found an overrepresentation of child maltreatment reports among ethnic minority groups. In this commentary, we reflect on a series of articles examining maltreatment from a crosscultural perspective and using samples of diverse countries. Taken together, studies in this special section document the terrible fact that maltreatment is a global phenomenon. Through a summary of these studies' main findings and concerns, we highlight four key points that we believe are important to consider for future research and intervention efforts.

  4. [Healing of harmony: music therapy as a historical cultural phenomenon].

    PubMed

    Gantenbein, U L

    1999-05-20

    The interaction of music and psyche constitutes a phenomenon, which is known to man since antiquity, and, for this reason, was ever since used for healing purposes. The pythagoreans developed a system of musical theory that declared consonance to be a musical interval with the frequencies in a ratio of integer numbers. The cosmical music of the spheres, the played instrumental music and the inner music of man, these all they conceived as a unity. Varied in a manyfold way, this great theme was handed down over the centuries to the present day, being a source of inspiration to music and the sciences. Modern musical therapy is, in the last analysis, based on these intuitive findings.

  5. Quantum phase slip phenomenon in ultra-narrow superconducting nanorings

    PubMed Central

    Arutyunov, Konstantin Yu.; Hongisto, Terhi T.; Lehtinen, Janne S.; Leino, Leena I.; Vasiliev, Alexander L.

    2012-01-01

    The smaller the system, typically - the higher is the impact of fluctuations. In narrow superconducting wires sufficiently close to the critical temperature Tc thermal fluctuations are responsible for the experimentally observable finite resistance. Quite recently it became possible to fabricate sub-10 nm superconducting structures, where the finite resistivity was reported within the whole range of experimentally obtainable temperatures. The observation has been associated with quantum fluctuations capable to quench zero resistivity in superconducting nanowires even at temperatures T→0. Here we demonstrate that in tiny superconducting nanorings the same phenomenon is responsible for suppression of another basic attribute of superconductivity - persistent currents - dramatically affecting their magnitude, the period and the shape of the current-phase relation. The effect is of fundamental importance demonstrating the impact of quantum fluctuations on the ground state of a macroscopically coherent system, and should be taken into consideration in various nanoelectronic applications. PMID:22389762

  6. A rational approach to the traveling wave phenomenon.

    PubMed

    Tonndorf, J

    1979-01-01

    To aid comprehension of cochlear traveling waves, the present article will explain this complex phenomenon in terms of its underlying principles: (1) fluid mechanics, with particular reference to a tangible, analogous event, wave transformation on sloping beaches; (2) the central role of the cochlear stiffness gradient with respect to an energy exchange between travel speed and amplitude of cochlear waves, low pass filter action with distance, and impedance matching for the benefit of wave progression; (3) spatial domain and frequency domain considerations; (4) the solution to the classic dilemma between cochlear tuning and damping; and (5) the task of the helicotrema. I will not discuss the ultimate mechanical stimulation of cochlear hair cells that is mediated by shearing interactions between the tectorial membrane and the organ proper.

  7. [Raynaud's phenomenon and other circulatory disorders of the fingers].

    PubMed

    Mahler, Felix

    2014-02-26

    Raynaud's phenomenon (RP) is defined as attacks of blanking, subsequent cyanosis and rubeosis of fingers due to vasospasms in response to cold or emotional stimuli. Primary RP has no known underlying cause and occurs mainly in young and otherwise healthy women. Secondary RP goes along with various causes such as connective tissue diseases, toxic substances, drugs, physical trauma or organic finger artery occlusions, and occurs at any age and in both genders. Related affections are acrocyanosis and finger artery occlusions either due to arteriosclerosis or vasculitis. Also spontaneous finger hematoma may provoke an episode of RP. Therapeutically strict cold protection and avoidance of possible noxa is recommended besides the treatment of underlying diseases. No standard vasoactive drug has proven ideal for RP due to side effects. In cases with rest pain or ulcerations the same principles are applied as in ischemic diseases with no possibility for revascularization.

  8. Air Conditioning Stall Phenomenon Testing, Model Development, and Simulation

    SciTech Connect

    Irminger, Philip; Rizy, D Tom; Li, Huijuan; Smith, Travis; Rice, C Keith; Li, Fangxing; Adhikari, Sarina

    2012-01-01

    Electric distribution systems are experiencing power quality issues of extended reduced voltage due to fault-induced delayed voltage recovery (FIDVR). FIDVR occurs in part because modern air conditioner (A/C) and heat pump compressor motors are much more susceptible to stalling during a voltage sag or dip such as a sub-transmission fault. They are more susceptible than older A/C compressor motors due to the low inertia of these newer and more energy efficient motors. There is a concern that these local reduced voltage events on the distribution system will become more frequent and prevalent and will combine over larger areas and challenge transmission system voltage and ultimately power grid reliability. The Distributed Energy Communications and Controls (DECC) Laboratory at Oak Ridge National Laboratory (ORNL) has been employed to (1) test, (2) characterize and (3) model the A/C stall phenomenon.

  9. [Eluding clinical medicine: a phenomenon that can be stopped].

    PubMed

    Benor, Dan E

    2010-04-01

    A study published in this issue (Lotan et at.) reveals distressing data on the percentage of 4th year students, after their first clerkship, that regret their choice of medicine as a career and contemplate a non-clinical vocational path. This phenomenon, entitled "eluding clinical medicine", is analyzed in terms of early professional socialization of the students toward sciences and their difficulty to tolerate ambiguity and uncertainty, so typical to clinical medicine. Also discussed is the student's incapability to integrate acquired knowledge across disciplines and to interweave it into clinical reality. Rectification of this escape from clinical medicine" may require modification of the pattern of the students' professional socialization during their first years of studies by such measures as early clinical exposure, interdisciplinary integration and practice in decision-making and problem-solving throughout the so-called "preclinical phase". The alarming findings presented in the above-mentioned study call for immediate response.

  10. [Spontaneous Non Ischaemic Blue Finger: A Rare and Benign Phenomenon].

    PubMed

    Franco, Daniela; Alves, Daniela; Almeida, Ana Cristina; Almeida, Carlos Costa; Moreno, Cecília; Freixo, Joâo

    2015-01-01

    The spontaneous non-ischaemic blue finger is a rare and benign disorder, characterized by purple discoloration of a finger, with complete resolution. This article reports the case of a woman of 88 years, which after a few hours of stay in the emergency department developed without associated trauma, a purplish color of the 3rd finger of the right hand, with a palpable pulse and without temperature changes or pain. The etiological investigation was negative. The patient was assessed one week after the event and showed completeresolution. There are several diseases that share the same signs and symptoms, as such the diagnosis is based on the spontaneous violaceous color sparing the finger tip, and fast resolution without treatment. Though being a harmless phenomenon, it requires early assessment for timely differential diagnosis with severe pathologies.

  11. Preliminary Numerical and Experimental Analysis of the Spallation Phenomenon

    NASA Technical Reports Server (NTRS)

    Martin, Alexandre; Bailey, Sean C. C.; Panerai, Francesco; Davuluri, Raghava S. C.; Vazsonyi, Alexander R.; Zhang, Huaibao; Lippay, Zachary S.; Mansour, Nagi N.; Inman, Jennifer A.; Bathel, Brett F.; Splinter, Scott C.; Danehy, Paul M.

    2015-01-01

    The spallation phenomenon was studied through numerical analysis using a coupled Lagrangian particle tracking code and a hypersonic aerothermodynamics computational fluid dynamics solver. The results show that carbon emission from spalled particles results in a significant modification of the gas composition of the post shock layer. Preliminary results from a test-campaign at the NASA Langley HYMETS facility are presented. Using an automated image processing of high-speed images, two-dimensional velocity vectors of the spalled particles were calculated. In a 30 second test at 100 W/cm2 of cold-wall heat-flux, more than 1300 particles were detected, with an average velocity of 102 m/s, and most frequent observed velocity of 60 m/s.

  12. Trance and the trickster: hypnosis as a liminal phenomenon.

    PubMed

    Krippner, Stanley

    2005-04-01

    This paper makes the case that hypnotic phenomena are liminal in nature and that hypnotic practitioners (such as Milton Erickson) share many traits with traditional societies' "tricksters." The ambiguous nature of hypnosis has been apparent since the days of Mesmer's animal magnetism. Hypnotized people often report hallucinations that confound their ordinary distinctions between reality and illusion, external and internal processes, and many other binary oppositions, including time and space as well as mind and body. In addition, hypnosis can obscure the distinction between fact and fiction in one's memory, as is evident in the "recovered memory" controversy. The role played by imagination is central to both indigenous rituals and hypnosis, and hypnosis is a multifaceted phenomenon requiring explanation at multiple levels. Some investigators and practitioners have missed the importance of the social context in which hypnosis occurs, while others have come close to destroying the most interesting and useful hypnotic phenomena under the guise of objectivity.

  13. The Superheat Phenomenon in the Combustion of Magnesium Particles

    NASA Technical Reports Server (NTRS)

    Shafirovich, E. IA.; Goldshleger, U. I.

    1992-01-01

    Magnesium is known to be a likely fuel for engines that could work in the CO2 atmospheres of Mars and Venus. The present paper reports temperature measurements of magnesium samples during combustion in CO2. The burning sample temperature increases with the decrease in the initial size. The temperature of the 1-mm samples is 300-400 K higher than the boiling point of magnesium. The stability of the superheated drop is explained by the presence of a porous shell on the surface. An attempt has been made to describe vaporization on the superheated drop by the Knudsen-Langmuir equation. During combustion at high-pressure fragment ejection of the flame is observed in high-speed motion pictures. This phenomenon is shown to be connected with the drop superheat. The repeated fracture of the outer shell formed in the flame ensures the complete burnout of metal particles at high pressure.

  14. Aggregation-induced emission: phenomenon, mechanism and applications.

    PubMed

    Hong, Yuning; Lam, Jacky W Y; Tang, Ben Zhong

    2009-08-07

    It is textbook knowledge that chromophore aggregation generally quenches light emission. In this feature article, we give an account on how we observed an opposite phenomenon termed aggregation-induced emission (AIE) and identified the restriction of intramolecular rotation as a main cause for the AIE effect. Based on the mechanistic understanding, we developed a series of new fluorescent and phosphorescent AIE systems with emission colours covering the entire visible spectral region and luminescence quantum yields up to unity. We explored high-tech applications of the AIE luminogens as, for example, fluorescence sensors (for explosive, ion, pH, temperature, viscosity, pressure, etc.), biological probes (for protein, DNA, RNA, sugar, phospholipid, etc.), immunoassay markers, PAGE visualization agents, polarized light emitters, monitors for layer-by-layer assembly, reporters for micelle formation, multistimuli-responsive nanomaterials, and active layers in the fabrication of organic light-emitting diodes.

  15. The double generalization phenomenon in juvenile absence epilepsy.

    PubMed

    San-Juan, Daniel; Mayorga, Adriana Patricia M; Anschel, David J; Avellán, Alvaro Moreno; González-Aragón, Maricarmen F; Cole, Andrew J

    2011-07-01

    The characterization of a seizure as generalized or focal onset depends on a basic knowledge of the underlying pathophysiology. Recently, an uncommon phenomenon in generalized epilepsy-evolution of seizures from generalized to focal followed by secondary generalization-was reported for the first time. We describe a 15-year-old boy, initially classified as having partial epilepsy, who had a typical absence seizure that became focal with second secondary generalization (double generalization). On the basis of these findings his epilepsy was classified as juvenile absence epilepsy and his treatment was changed, resulting in seizure freedom. This is the first report of this unusual electroclinical evolution in a patient with juvenile absence epilepsy. The recognition of this particular pattern allows correct classification and impacts both treatment and prognosis.

  16. Evolution as a self-organized critical phenomenon

    SciTech Connect

    Sneppen, K.; Bak, P. |; Flyvbjerg, H. |; Jensen, M.H.

    1995-05-23

    We present a simple mathematical model of biological macroevolution. The model describes an ecology of adapting, interacting species. The environment of any given species is affected by other evolving species; hence, it is not constant in time. The ecology as a whole evolves to a {open_quotes}self-organized critical{close_quotes} state where periods of stasis alternate with avalanches of casually connected evolutionary changes. This characteristic behavior of natural history, known as {open_quotes}punctuated equilibrium,{close_quotes} thus finds a theoretical explanation as a self-organized critical phenomenon. The evolutionary behavior of single species is intermittent. Also, large bursts of apparently simultaneous evolutionary activity require no external cause. Extinctions of all sizes, including mass extinctions, may be a simple consequence of ecosystem dynamics. Our results are compared with data from the fossil record. 35 refs., 7 figs.

  17. Genetic aspects of athletic performance: the African runners phenomenon.

    PubMed

    Vancini, Rodrigo Luiz; Pesquero, João Bosco; Fachina, Rafael Júlio; Andrade, Marília Dos Santos; Borin, João Paulo; Montagner, Paulo César; de Lira, Claudio Andre Barbosa

    2014-01-01

    The current dominance of African runners in long-distance running is an intriguing phenomenon that highlights the close relationship between genetics and physical performance. Many factors in the interesting interaction between genotype and phenotype (eg, high cardiorespiratory fitness, higher hemoglobin concentration, good metabolic efficiency, muscle fiber composition, enzyme profile, diet, altitude training, and psychological aspects) have been proposed in the attempt to explain the extraordinary success of these runners. Increasing evidence shows that genetics may be a determining factor in physical and athletic performance. But, could this also be true for African long-distance runners? Based on this question, this brief review proposed the role of genetic factors (mitochondrial deoxyribonucleic acid, the Y chromosome, and the angiotensin-converting enzyme and the alpha-actinin-3 genes) in the amazing athletic performance observed in African runners, especially the Kenyans and Ethiopians, despite their environmental constraints.

  18. Genetic aspects of athletic performance: the African runners phenomenon

    PubMed Central

    Vancini, Rodrigo Luiz; Pesquero, João Bosco; Fachina, Rafael Júlio; Andrade, Marília dos Santos; Borin, João Paulo; Montagner, Paulo César; de Lira, Claudio Andre Barbosa

    2014-01-01

    The current dominance of African runners in long-distance running is an intriguing phenomenon that highlights the close relationship between genetics and physical performance. Many factors in the interesting interaction between genotype and phenotype (eg, high cardiorespiratory fitness, higher hemoglobin concentration, good metabolic efficiency, muscle fiber composition, enzyme profile, diet, altitude training, and psychological aspects) have been proposed in the attempt to explain the extraordinary success of these runners. Increasing evidence shows that genetics may be a determining factor in physical and athletic performance. But, could this also be true for African long-distance runners? Based on this question, this brief review proposed the role of genetic factors (mitochondrial deoxyribonucleic acid, the Y chromosome, and the angiotensin-converting enzyme and the alpha-actinin-3 genes) in the amazing athletic performance observed in African runners, especially the Kenyans and Ethiopians, despite their environmental constraints. PMID:24891818

  19. Retrospective Revaluation: The Phenomenon and Its Theoretical Implications

    PubMed Central

    Miller, Ralph R.; Witnauer, James E.

    2015-01-01

    Retrospective revaluation refers to an increase (or decrease) in responding to conditioned stimulus (CS X) as a result of decreasing (or increasing) the associative strength of another CS (A) with respect to the unconditioned stimulus (i.e., A-US) that was previously trained in compound with the target CS (e.g., AX−US or just AX). We discuss the conditions under which retrospective revaluation phenomena are most apt to be observed and their implications for various models of learning that are able to account for retrospective revaluation (e.g., Dickinson and Burke, 1996; Miller and Matzel, 1988; Van Hamme and Wasserman, 1994). Although retroactive revaluation is relatively parameter specific, it is seen to be a reliable phenomenon observed across many tasks and species. As it is not anticipated by many conventional models of learning (e.g., Rescorla and Wagner, 1972), it serves as a critical benchmark for evaluating traditional and newer models. PMID:26342855

  20. A nonextensive critical phenomenon scenario for quantum entanglement

    NASA Astrophysics Data System (ADS)

    Tsallis, Constantino; Lamberti, Pedro W.; Prato, Domingo

    2001-06-01

    We discuss the paradigmatic bipartite spin- {1}/{2} system having the probabilities (1+3 x)/4 of being in the Einstein-Podolsky-Rosen fully entangled state |Ψ ->≡1/ 2(|↑> A|↓> B-|↓> A|↑> B) and 3(1- x)/4 of being orthogonal. This system is known to be separable if and only if x⩽ {1}/{3} (Peres criterion). This critical value has been recently recovered by Abe and Rajagopal through the use of the nonextensive entropic form S q≡(1-Tr ρ q)/(q-1) (q∈ R; S 1=-Tr ρ ln ρ) which has enabled a current generalization of Boltzmann-Gibbs statistical mechanics. This result has been enrichened by Lloyd, Baranger and one of the present authors by proposing a critical-phenomenon-like scenario for quantum entanglement. Here, we further illustrate and discuss this scenario through the calculation of some relevant quantities.

  1. Suicide tourism: a pilot study on the Swiss phenomenon.

    PubMed

    Gauthier, Saskia; Mausbach, Julian; Reisch, Thomas; Bartsch, Christine

    2015-08-01

    While assisted suicide (AS) is strictly restricted in many countries, it is not clearly regulated by law in Switzerland. This imbalance leads to an influx of people-'suicide tourists'-coming to Switzerland, mainly to the Canton of Zurich, for the sole purpose of committing suicide. Political debate regarding 'suicide tourism' is taking place in many countries. Swiss medicolegal experts are confronted with these cases almost daily, which prompted our scientific investigation of the phenomenon. The present study has three aims: (1) to determine selected details about AS in the study group (age, gender and country of residence of the suicide tourists, the organisation involved, the ingested substance leading to death and any diseases that were the main reason for AS); (2) to find out the countries from which suicide tourists come and to review existing laws in the top three in order to test the hypothesis that suicide tourism leads to the amendment of existing regulations in foreign countries; and (3) to compare our results with those of earlier studies in Zurich. We did a retrospective data analysis of the Zurich Institute of Legal Medicine database on AS of non-Swiss residents in the last 5 years (2008-2012), and internet research for current legislation and political debate in the three foreign countries most concerned. We analysed 611 cases from 31 countries all over the world. Non-terminal conditions such as neurological and rheumatic diseases are increasing among suicide tourists. The unique phenomenon of suicide tourism in Switzerland may indeed result in the amendment or supplementary guidelines to existing regulations in foreign countries.

  2. Vacuum Phenomenon of the Sacroiliac Joint: Correlation with Sacropelvic Morphology

    PubMed Central

    Higashino, Kosaku; Morimoto, Masatoshi; Sakai, Toshinori; Yamashita, Kazuta; Abe, Mitusnobu; Nagamachi, Akihiro; Sairyo, Koichi

    2016-01-01

    Study Design A radiologic study of sacropelvic morphology and vacuum phenomenon of sacroiliac joint in subjects unrelated to low back pain. Purpose The aim of this study is to describe the relationship between sacropelvic morphology and vacuum phenomenon of the sacroiliac joint. Overview of Literature Lumbopelvic alignment and sacropelvic morphology are associated with the pathomechanisms of various spinal disorders. The vacuum phenomena of the sacroiliac joint (SJVP) are often observed in clinical practice, but the relationships between these phenomena and sacropelvic morphology have not been investigated. This study examined the prevalence of SJVP in computed tomography (CT) images and the relationship between sacropelvic morphology and SJVP. Methods We analyzed multiplanar CT images of 93 subjects (59 men, 34 women). Pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), and lumbar lordosis (LL) were measured using the three-dimensional reconstruction method. The prevalence of SJVP in multiplanar CT images were reviewed. Roland-Morris Disability Questionnaire (RDQ) scores and the modified Japanese Orthopedic Association (JOA) score, which focuses on subjective symptoms and restriction of activities of daily living, were also obtained from all the subjects. Results Thirty-six of the 93 subjects had SJVP (39%), with marked female predominance (91% women, 8.5% men). Men with SJVP had significantly lower PI than men without SJVP (35.1° vs. 46.3°, p<0.05). There was no correlation between SJVP and the modified JOA or RDQ scores. Conclusions These data suggest that differences in sacropelvic morphology can influence the biomechanical environment and contribute to SJVP in men. Presence of SJVP did not affect JOA or RDQ scores. PMID:27559459

  3. Automatic arteriovenous crossing phenomenon detection on retinal fundus images

    NASA Astrophysics Data System (ADS)

    Hatanaka, Yuji; Muramatsu, Chisako; Hara, Takeshi; Fujita, Hiroshi

    2011-03-01

    Arteriolosclerosis is one cause of acquired blindness. Retinal fundus image examination is useful for early detection of arteriolosclerosis. In order to diagnose the presence of arteriolosclerosis, the physicians find the silver-wire arteries, the copper-wire arteries and arteriovenous crossing phenomenon on retinal fundus images. The focus of this study was to develop the automated detection method of the arteriovenous crossing phenomenon on the retinal images. The blood vessel regions were detected by using a double ring filter, and the crossing sections of artery and vein were detected by using a ring filter. The center of that ring was an interest point, and that point was determined as a crossing section when there were over four blood vessel segments on that ring. And two blood vessels gone through on the ring were classified into artery and vein by using the pixel values on red and blue component image. Finally, V2-to-V1 ratio was measured for recognition of abnormalities. V1 was the venous diameter far from the blood vessel crossing section, and V2 was the venous diameter near from the blood vessel crossing section. The crossing section with V2-to-V1 ratio over 0.8 was experimentally determined as abnormality. Twenty four images, including 27 abnormalities and 54 normal crossing sections, were used for preliminary evaluation of the proposed method. The proposed method was detected 73% of crossing sections when the 2.8 sections per image were mis-detected. And, 59% of abnormalities were detected by measurement of V1-to-V2 ratio when the 1.7 sections per image were mis-detected.

  4. Credit use: psychological perspectives on a multifaceted phenomenon.

    PubMed

    Kamleitner, Bernadette; Hoelzl, Erik; Kirchler, Erich

    2012-01-01

    Consumer borrowing is a highly topical and multifaceted phenomenon as well as a popular subject for study. We focus on consumer credit use and review the existing literature. To categorize what is known we identify four main psychological perspectives on the phenomenon: credit use as (1) a reflection of the situation, (2) a reflection of the person, (3) a cognitive process, and (4) a social process. On top of these perspectives we view credit use as a process that entails three distinct phases: (1) processes before credit acquisition, (2) processes at credit acquisition, and (3) processes after credit acquisition. We review the international literature along a two-tier structure that aligns the psychological perspectives with a process view of credit. This structure allows us to identify systematic concentrations as well as gaps in the existing research. We consolidate what is known within each perspective and identify what seems to be most urgently missing. Some of the most important gaps relate to research studying credit acquisition from the perspective of credit use as a reflection of the person or as a social process. In particular, research on credit use as a reflection of the person appears to focus exclusively on the first stage of the credit process. We conclude with a discussion that reaches across perspectives and identifies overarching gaps, trends, and open questions. We highlight a series of implicit linkages between perspectives and the geographical regions in which studies related to the perspectives were conducted. Beyond diagnosing a geographical imbalance of research, we argue for future research that systematically addresses interrelations between perspectives. We conclude with a set of global implications and research recommendations.

  5. Altered microrheological parameters in Raynaud's phenomenon.

    PubMed

    Papp, Judit; Sandor, Barbara; Toth, Andras; Biro, Katalin; Rabai, Miklos; Botor, David; Kovacs, David; Csernus, Zita; Toth, Kalman; Kesmarky, Gabor

    2017-01-01

    Raynaud's phenomenon is an episodic, painful attack of the acral parts caused by local diminished blood supply. The aim of our study was to examine hemorheological parameters, cold agglutinins, cryoglobulins and their relationship in patients suffering from Raynaud's phenomenon.Blood was taken from 74 patients (mean age: 48 years, female/male: 56/18). Cold agglutinins and cryoglobulins were determined. Hemorheological parameters were also measured such as hematocrit, plasma and whole blood viscosity, red blood cell aggregation and deformability. Results were compared to a group of 58 healthy controls (mean age: 31.5 years, female/male: 24/34).Cold agglutinins were positive in 70%, cryoglobulins in 43% of patients. When compared to healthy controls, increased red blood cell aggregation (64.54  ±  8.93 vs. 61.11  ±  7.05) and decreased red blood cell deformability (0.669  ±  0.002 vs. 0.681  ±  0.001) was observed in Raynaud's patients (p < 0.05), but there were no differences in hematocrit (43.27% ± 3.85 vs. 44.10% ± 3.70), plasma (1.27 mPas ± 0.08 vs. 1.24 mPas ± 0.09) and whole blood viscosity (4.12 mPas ± 0.52 vs. 4.26 mPas ± 0.46). No differences were found between the hemorheological profile of cold agglutinin/cryoglobulin positive and negative patients. Also primary and secondary Raynaud's patients had similar rheological profile.Erythrocyte aggregation and deformability seems to be unfavorable in Raynaud's patients that can play a role in the disturbance of the microcirculation.

  6. On the cause of the flat-spot phenomenon observed in silicon solar cells at low temperatures and low intensities

    NASA Technical Reports Server (NTRS)

    Weizer, V. G.; Broder, J. D.; Brandhorst, H. W., Jr.; Forestieri, A. F.

    1982-01-01

    A model that explains the flat-spot power loss phenomenon is presented. Evidence suggests that the effect is due to localized metallurgical interactions between the silicon substrate and the contact metallization. These reactions are shown to result in localized regions in which the P-N junction is destroyed and replaced with a metal semiconductor-like interface. The effects of thermal treatment, crystallographic orientation, junction depth, and metallization are shown along with a method of preventing the effect through the suppression of vacancy formation at the free surface of the contact metallization. Data indicating the effectiveness of a TiN diffusion barrier in preventing the effect are also given.

  7. Aquatic Organic Matter Fluorescence - from phenomenon to application

    NASA Astrophysics Data System (ADS)

    Reynolds, Darren

    2014-05-01

    The use of fluorescence to quantify and characterise aquatic organic matter in river, ocean, ground water and drinking and waste waters has come along way since its discovery as a phenomenon in the early 20th century. For example, there are over 100 papers published each year in international peer reviewed journals, an order of magnitude increase since a decade ago (see Figure taken from ISI database from 1989 to 2007 for publications in the fields of river water and waste water). Since then it has been extensively used as a research tool since the 1990's by scientists and is currently used for a wide variety of applications within a number of sectors. Universities, organisations and companies that research into aquatic organic matter have either recently readily use appropriate fluorescence based techniques and instrumentation. In industry and government, the technology is being taken up by environmental regulators and water and wastewater companies. This keynote presentation will give an overview of aquatic organic matter fluorescence from its conception as a phenomenon through to its current use in a variety of emerging applications within the sectors concerned with understanding, managing and monitoring the aquatic environment. About the Speaker Darren Reynolds pioneered the use of fluorescence spectroscopy for the analysis of wastewaters in the 1990's. He currently leads a research group within the Centre for Research in Biosciences and sits on the Scientific Advisory Board for the Institute of Bio-Sensing Technology at the University of the West of England, Bristol. He is a multidisciplinary scientist concerned with the development of technology platforms for applications in the fields of environment/agri-food and health. His current research interests include the development of optical technologies and techniques for environmental and biological sensing and bio-prospecting applications. He is currently involved in the development and use of synthetic biology

  8. Percolation phenomenon in mixed reverse micelles: the effect of additives.

    PubMed

    Paul, Bidyut K; Mitra, Rajib K

    2006-03-01

    The conductivity of AOT/IPM/water reverse micellar systems as a function of temperature, has been found to be non-percolating at three different concentrations (100, 175 and 250 mM), while the addition of nonionic surfactants [polyoxyethylene(10) cetyl ether (Brij-56) and polyoxyethylene(20) cetyl ether (Brij-58)] to these systems exhibits temperature-induced percolation in conductance in non-percolating AOT/isopropyl myristate (IPM)/water system at constant compositions (i.e., at fixed total surfactant concentration, omega and X(nonionic)). The influence of total surfactant concentration (micellar concentration) on the temperature-induced percolation behaviors of these systems has been investigated. The effect of Brij-58 is more pronounced than that of Brij-56 in inducing percolation. The threshold percolation temperature, Tp has been determined for these systems in presence of additives of different molecular structures, physical parameters and/or interfacial properties. The additives have shown both assisting and resisting effects on the percolation threshold. The additives, bile salt (sodium cholate), urea, formamide, cholesteryl acetate, cholesteryl benzoate, toluene, a triblock copolymer [(EO)13(PO)30(EO)13, Pluronic, PL64], polybutadiene, sucrose esters (sucrose dodecanoates, L-1695 and sucrose monostearate S-1670), formamide distinctively fall in the former category, whereas sodium chloride, cholesteryl palmitate, crown ether, ethylene glycol constitute the latter for both systems. Sucrose dodecanoates (L-595) had almost marginal effect on the process. The observed behavior of these additives on the percolation phenomenon has been explained in terms of critical packing parameter and/or other factors, which influence the texture of the interface and solution properties of the mixed reverse micellar systems. The activation energy, Ep for the percolation process has been evaluated. Ep values for the AOT/Brij-56 systems have been found to be lower than those of

  9. [The significance of cervical collaterals in the subclavian steal phenomenon].

    PubMed

    Yamaguchi, K; Uchiyama, S

    1993-09-01

    The subclavian steal syndrome (SSS) is often associated with occlusive disease involving the subclavian or innominate arteries, but an asymptomatic subclavian steal, called the "subclavian steal phenomenon" (SSP), is not uncommon. Though intracranial collaterals had been postulated as one of the etiologies for the SSP's being asymptomatic, little has been accomplished in the investigation of extracranial channels. To study the hemodynamic role of cervical collateral channels, an angiographical study was done in three cases with SSP. The three cases were admitted to the hospital because of carotid ischemic symptoms, such as right hemiplegia or sensory aphasia. Each case had a blood pressure difference between the two arms, but in all of them the past history or the exercise test was negative for vertebrobasilar or arm ischemia. On angiography, occlusions of the unilateral proximal subclavian artery, the left in case 1 and the right in case 2, or a tight stenosis of the innominate artery was found in case 3. In each case, the vertebral artery flow in the affected side was inverted, siphoning off from the opposite vertebral artery into the affected subclavian artery. In addition to the vertebral siphoning; muscular branches of ipsilateral external carotid origin in cases 1 and 2, or the thyrocervical trunk via the inferior thyroid artery in case 3 was also found to function as a collateral channel to the vertebral artery on the affected side.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. Deadline rush: a time management phenomenon and its mathematical description.

    PubMed

    König, Cornelius J; Kleinmann, Martin

    2005-01-01

    A typical time management phenomenon is the rush before a deadline. Behavioral decision making research can be used to predict how behavior changes before a deadline. People are likely not to work on a project with a deadline in the far future because they generally discount future outcomes. Only when the deadline is close are people likely to work. On the basis of recent intertemporal choice experiments, the authors argue that a hyperbolic function should provide a more accurate description of the deadline rush than an exponential function predicted by an economic model of discounted utility. To show this, the fit of the hyperbolic and the exponential function were compared with data sets that describe when students study for exams. As predicted, the hyperbolic function fit the data significantly better than the exponential function. The implication for time management decisions is that they are most likely to be inconsistent over time (i.e., people make a plan how to use their time but do not follow it).

  11. When does single-mode lasing become a condensation phenomenon?

    PubMed

    Fischer, Baruch; Weill, Rafi

    2012-11-19

    We present a generic route to classical light condensation (LC) in linear photonic mode systems, such as cw lasers, with different grounds from regular Bose-Einstein condensation (BEC). LC is based on weighting the modes in a noisy environment (spontaneous emission, etc.) in a loss-gain scale, rather than in photon energy. It is characterized by a sharp transition from a multi- to single-mode oscillation. The study uses a linear multivariate Langevin formulation which gives a mode occupation hierarchy that functions like Bose-Einstein statistics. Condensation occurs when the spectral filtering has near the lowest-loss mode a power law dependence with exponent smaller than 1. We then discuss how condensation can occur in photon systems, its relation to lasing and the difficulties to observe regular photon-BEC in laser cavities. We raise the possibility that experiments on photon condensation in optical cavities fall in a classical LC or lasing category rather than being a thermal-quantum BEC phenomenon.

  12. [Some Italian research on the phenomenon of filicide].

    PubMed

    Mastronardi, Vincenzo; De Vita, Luana; Umani Ronchi, Federica

    2012-01-01

    In this work on the phenomenon of filicide, structured on the basis of the examination of hundreds of cases from 1880 to 2010, the five causes were taken into account: the altruistic filicide, the high psychotic component, that of the unwanted child, accidental filicide, and the spouse revenge filicide. Following the observation of Resnick's (1969) 530 psycho-biographiesss, a more structured typing was developed which on the basis of their motive and/or psychopathology divides mother infanticide into 20 categories: the first 10 imply full imputability, stessor events, for piety, immaturity of the mother, hyperactivity of the child, the son of the blame, Medea syndrome, disturbance dependent, narcissistic, or histrionic personality, unwanted child, depression, behavioral disorders involved in the recruitment of drugs. The remaining 10 are those where there may be impairment of traceability for postpartum psychosis (Brief psychotic disorder), Fundus hysterical plus precipitating factors, major depression, schizophrenia, twilight state, psychotic disorder due to a general medical condition, epilepsy, oligophrenia, multiple sclerosis and multiple personality, which however appears to be quite rare. An examination of the causes of death concludes the work.

  13. Proof phenomenon as a function of the phenomenology of proving.

    PubMed

    Hipólito, Inês

    2015-12-01

    Kurt Gödel wrote (1964, p. 272), after he had read Husserl, that the notion of objectivity raises a question: "the question of the objective existence of the objects of mathematical intuition (which, incidentally, is an exact replica of the question of the objective existence of the outer world)". This "exact replica" brings to mind the close analogy Husserl saw between our intuition of essences in Wesensschau and of physical objects in perception. What is it like to experience a mathematical proving process? What is the ontological status of a mathematical proof? Can computer assisted provers output a proof? Taking a naturalized world account, I will assess the relationship between mathematics, the physical world and consciousness by introducing a significant conceptual distinction between proving and proof. I will propose that proving is a phenomenological conscious experience. This experience involves a combination of what Kurt Gödel called intuition, and what Husserl called intentionality. In contrast, proof is a function of that process - the mathematical phenomenon - that objectively self-presents a property in the world, and that results from a spatiotemporal unity being subject to the exact laws of nature. In this essay, I apply phenomenology to mathematical proving as a performance of consciousness, that is, a lived experience expressed and formalized in language, in which there is the possibility of formulating intersubjectively shareable meanings.

  14. [The Reverse Traffic of Drugs Phenomenon: experience in Galicia, Spain].

    PubMed

    Vázquez-Mourelle, Raquel; Rodriguez Costa, Elia; Pose Reino, José Manuel; Cadórniga Valiño, Luis

    2015-10-01

    IInter-state movement of drugs between EU countries by pharmaceutical companies and distribution warehouses is a permitted activity called parallel trade. As Spain is among the states with lower price of these products, its main activity is shipping to other countries; however, a phenomenon has emerged in acquiring drugs for this purpose, called "reverse traffic" that develops without observing the health regulations in the legal distribution channel in our country; in which, the pharmaceutical distribution warehouses, rather than getting drugs from other pharmaceutical companies or pharmaceutical distribution warehouses under the current legislation, obtain them from community pharmacies, thus reversing the legal supply circuit, as this drugs do not end dispensed to the public. This paper studies the risks to public health caused by these practices, detailing the results of health inspections in Galicia, where in relation to the total pharmaceutical establishments sanctioning procedures in the period 2011-2014, were sanctioned for this reason 15 community pharmacies and 5 distribution warehouses, the maximum fines belonging to a network consisting of a pharmaceutical distribution warehouse, with a 1,000,000 € fine and closure for 3 years, and 4 community pharmacies, with 2,400,000 € total fine; It also specifies the methodology of action, identifies the scene of illegal acquisition to make this trade with the greatest economic benefits, highlights the strengths of the success and further action to improve its approach.

  15. The Electrophysiological Phenomenon of Alzheimer's Disease: A Psychopathology Theory.

    PubMed

    Holston, Ezra C

    2015-08-01

    The current understanding of Alzheimer's disease (AD) is based on the Aβ and tau pathology and the resulting neuropathological changes, which are associated with manifested clinical symptoms. However, electrophysiological brain changes may provide a more expansive understanding of AD. Hence, the objective of this systematic review is to propose a theory about the electrophysiological phenomenon of Alzheimer's disease (EPAD). The review of literature resulted from an extensive search of PubMed and MEDLINE databases. One-hundred articles were purposively selected. They provided an understanding of the concepts establishing the theory of EPAD (neuropathological changes, neurochemical changes, metabolic changes, and electrophysiological brain changes). Changes in the electrophysiology of the brain are foundational to the association or interaction of the concepts. Building on Berger's Psychophysical Model, it is evident that electrophysiological brain changes occur and affect cortical areas to generate or manifest symptoms from onset and across the stages of AD, which may be prior to pathological changes. Therefore, the interaction of the concepts demonstrates how the psychopathology results from affected electrophysiology of the brain. The theory of the EPAD provides a theoretical foundation for appropriate measurements of AD without dependence on neuropathological changes. Future research is warranted to further test this theory. Ultimately, this theory contributes to existing knowledge because it shows how electrophysiological changes are useful in understanding the risk and progression of AD across the stages.

  16. Metabolic memory phenomenon in diabetes mellitus: Achieving and perspectives.

    PubMed

    Berezin, Alexander

    2016-01-01

    Diabetes mellitus (DM) exhibits raised prevalence worldwide. There is a large body of evidence regarding the incidence of DM closely associates with cardiovascular (CV) complications. In this context, hyperglycaemia, oxidant stress, and inflammation are key factors that contribute in CV events and disease in type1 and type 2 DM, even when metabolic control was optimal and/or intensive glycemic control was implemented. It has been suggested that the effect of poor metabolic control or even transient episodes of hyperglycemia in DM associates in particularly with worsening ability of endogenous vasoreparative systems that are mediated epigenetic changes in several cells (progenitor cells, stem cells, mononuclears, immune cells), and thereby lead to so called "vascular glycemic memory" or "metabolic memory". Both terms are emphasized the fact that prior glucose control has sustained effects that persist even after return to more usual glycemic control. The mechanisms underlying the cellular "metabolic memory" induced by high glucose remain unclear. The review is discussed pathophysiology and clinical relevance of "metabolic" memory phenomenon in DM. The role of oxidative stress, inflammation, and epigenetics in DM and its vascular complications are highlighted. The effects of several therapeutic approaches are discussed.

  17. On the self-heating phenomenon in nonmodal shear flow

    SciTech Connect

    Li, J.W.; Chen, Y.; Li, Z.Y.

    2006-04-15

    In this article, the nonmodal self-heating phenomenon of linear shear flow [A. D. Rogava, Astrophys. Space Sci. 293, 189 (2004)] is investigated with an initially excited Alfvenic perturbation focusing on the factors determining the efficiency of the heating process. It is found that to get an efficient self-heating process, the initial Alfven wave must be at least partially transformed into the fast mode. This is because only the fast mode, among the three types of magnetohydrodynamic modes, can get amplified significantly by the shear flow. This requires the initial wave number along the shear to be positive so that the Spatial Fourier Harmonics can pass through the degeneration region, and also puts constraints on the plasma parameter {beta} [{beta}=C{sub S}{sup 2}/V{sub A}{sup 2}, where C{sub S} (V{sub A}) is the sound (Alfvenic) velocity]. It is shown that the self-heating function, which represents the total energy dissipated at a certain time, decreases monotonically with increasing {beta}. In addition, to get efficient heating the viscous coefficient should be in an appropriate range. A smaller viscosity results in an insufficient thermalization of the perturbation energy, while a larger one corresponds to a suppressed nonmodal amplification.

  18. The Oral Tolerance as a Complex Network Phenomenon.

    PubMed

    Miranda, Pedro Jeferson; Delgobo, Murilo; Marino, Giovani Favero; Paludo, Kátia Sabrina; da Silva Baptista, Murilo; de Souza Pinto, Sandro Ely

    2015-01-01

    The phenomenon of oral tolerance refers to a local and systemic state of tolerance induced in the gut after its exposure to innocuous antigens. Recent findings have shown the interrelationship between cellular and molecular components of oral tolerance, but its representation through a network of interactions has not been investigated. Our work aims at identifying the causal relationship of each element in an oral tolerance network, and also to propose a phenomenological model that's capable of predicting the stochastic behavior of this network when under manipulation. We compared the changes of a "healthy" network caused by "knock-outs" (KOs) in two approaches: an analytical approach by the Perron Frobenius theory; and a computational approach, which we describe within this work in order to find numerical results for the model. Both approaches have shown the most relevant immunological components for this phenomena, that happens to corroborate the empirical results from animal models. Besides explain in a intelligible fashion how the components interacts in a complex manner, we also managed to describe and quantify the importance of KOs that hasn't been empirically tested.

  19. Open Dialogue Approach - about the phenomenon of Scandinavian Psychiatry.

    PubMed

    Kłapciński, Michał M; Rymaszewska, Joanna

    2015-01-01

    After twenty years of transformation of Finnish mental health care, in the late 80s and early 90s of the last century, incidence of schizophrenia in Western Lapland dropped from 35/100,000 to 7/100,000. This phenomenon is linked with Yrjo O. Alanen et al. who investigated schizophrenia treatment outcomes and psychosocial rehabilitation of people with schizophrenia. Investigators focused on an individually tailored psychotherapeutic recovery plan during patient's hospitalization, including care for patients' families. Within the "Finnish National Schizophrenia Project" the principles of the Need-Adapted Treatment were created and 50% of Finland's country gained access to mobile crisis intervention teams. Further studies were continued within "Acute PsychosisIntegrated Treatment Project" (1992-1993) which locally, in Western Lapland, proceeded into "Open Dialogue in Acute Psychosis Project" (ODAP) (1994-1997). In this approach, all important decisions regarding the patient, including hospitalization or pharmacotherapy, are discussed not only with the entire therapeutic team, but also with the patient and his family members. Two - and five-year follow-ups demonstrated high treatment efficacy as well as important cost reduction in mental health care spending. First two"Open Dialogue Method" training courses for representatives of the medical, psychological, nursing and social care have been completed in Poland in October 2014. Studies evaluating the therapeutic effectiveness of the described approach are being planned.

  20. Vacuum surface flashover: A high-pressure phenomenon

    SciTech Connect

    Gray, E.W.

    1985-07-01

    Desorbed gases from insulator surfaces may be much more important in flashover initiation than properties of the dielectric surface. Ambient neutral densities, immediately above the insulator surface, in the initial stages of flashover have been calculated to lie in the range from 2 x 10/sup 17//cm/sup 3/ to 2 x 10/sup 21//cm/sup 3/ with a mean of about 1 x 10/sup 19//cm/sup 3/, whether flashover occurred on surfaces in air at atmospheric pressure or in vacuum as low as 10/sup -6/ Torr. The evidence presented indicates that, for dc and microsecond pulse voltages, surface flashover is a local, relatively high-pressure phenomenon. Comparison of field strengths of surface flashover for various insulating materials perpendicular to the electrodes, operating pressures, and voltage waveforms appears to indicate that flashover values range well within an order of magnitude (approx.18--80kV/cm). A filamentary nature of the flashover discharge is shown and is consistent with gas breakdown phenomena. Ionization wave front velocities are examined and these compare favorably with those obtained from gaseous breakdown studies.

  1. Origin of the pinking phenomenon of white wines.

    PubMed

    Andrea-Silva, Jenny; Cosme, Fernanda; Ribeiro, Luís Filipe; Moreira, Ana S P; Malheiro, Aureliano C; Coimbra, Manuel A; Domingues, M Rosário M; Nunes, Fernando M

    2014-06-18

    Pinking is the terminology used for the salmon-red blush color that may appear in white wines produced exclusively from white grape varieties. The isolation of pinking compounds and their analysis by RP-HPLC-DAD and ESI-MS(n) showed that the origin of the pinking phenomenon in white wines from Vitis vinifera L. of Sı́ria grape variety are the anthocyanins, mainly malvidin-3-O-glucoside. The analysis showed that the anthocyanins were located both in the pulp and in the skin. Wine pinking severity was negatively related with the increase of the average temperature of the first 10 days of October, the final period of grape maturation. The minimum amount of anthocyanins needed for the pink color visualization in wine was 0.3 mg/L. The appearance of pinking in white wines after bottling is due to the lowering of free sulfur dioxide, which leads to an increase of the relative amount of the anthocyanins red flavylium form and their polymerization, resulting in the formation of colored compounds resistant to pH changes and sulfur dioxide bleaching.

  2. Transit of Venus Culture: A Celestial Phenomenon Intrigues the Public

    NASA Astrophysics Data System (ADS)

    Bueter, Chuck

    2012-01-01

    When Jeremiah Horrocks first observed it in 1639, the transit of Venus was a desirable telescopic target because of its scientific value. By the next transit of Venus in 1761, though, the enlightened public also embraced it as a popular celestial phenomenon. Its stature elevated over the centuries, the transit of Venus has been featured in music, poetry, stamps, plays, books, and art. The June 2004 transit emerged as a surprising global sensation, as suggested by the search queries it generated. Google's Zeitgeist deemed Venus Transit to be the #1 Most Popular Event in the world for that month. New priorities, technologies, and media have brought new audiences to the rare alignment. As the 2012 transit of Venus approaches, the trend continues with publicly accessible capabilities that did not exist only eight years prior. For example, sites from which historic observations have been made are plotted and readily available on Google Earth. A transit of Venus phone app in development will, if fully funded, facilitate a global effort to recreate historic expeditions by allowing smartphone users to submit their observed transit timings to a database for quantifying the Astronomical Unit. While maintaining relevance in modern scientific applications, the transit of Venus has emerged as a cultural attraction that briefly intrigues the mainstream public and inspires their active participation in the spectacle.

  3. Raynaud's phenomenon--or just skin with dye?

    PubMed

    Serinken, M; Karcioglu, O; Turkcuer, I; Bukiran, A

    2009-03-01

    Munchausen's syndrome is a factitious disorder resulting in unnecessary investigations and operative treatments in a small and well-defined population. Autobiographical falsification is the characteristic of the entity. The case history is presented of a 28-year-old woman admitted to the emergency department with severe pain of acute onset in her fingers and discoloration while washing dishes. She had been diagnosed with Raynaud's phenomenon and had been on antiepileptic drugs. The fingertips of both hands looked cyanotic. Radial and ulnar pulses were intact. She had argued with the personnel obtaining vital signs and had a tendency to hide her right hand, which raised the suspicion that a psychiatric disorder was the primary cause of the visit to the emergency department. A blue piece of dirt on the left shoulder had also augmented these concerns. Munchausen's syndrome was suspected after careful handshaking with hands soaked in alcohol resulted in a blue discoloration on the doctor's palm and fingers. Emergency and primary care physicians should be alert to this type of situation, with a myriad possible scenarios to be differentiated from real conditions.

  4. Sharp knee phenomenon of primary cosmic ray energy spectrum

    NASA Astrophysics Data System (ADS)

    Ter-Antonyan, Samvel

    2014-06-01

    Primary energy spectral models are tested in the energy range of 1-200 PeV using standardized extensive air shower responses from BASJE-MAS, Tibet, GAMMA and KASCADE scintillation shower arrays. Results point toward the two-component origin of observed cosmic ray energy spectra in the knee region consisting of a pulsar component superimposed upon rigidity-dependent power law diffuse Galactic flux. The two-component energy spectral model accounts for both the sharp knee shower spectral phenomenon and observed irregularity of all-particle energy spectrum in the region of 50-100 PeV. Alternatively, tested multipopulation primary energy spectra predicted by nonlinear diffusive shock acceleration models describe observed shower spectra in the knee region provided that the cutoff magnetic rigidities of accelerating particles are 6±0.3 and 45±2 PV for the first two populations, respectively. Both tested spectral models confirm the predominant H-He primary nuclei origin of observed shower spectral knee. The parameters of tested energy spectra are evaluated using solutions of the inverse problem on the basis of the corresponding parameterizations of energy spectra for primary H, He, O-like and Fe-like nuclei, standardized shower size spectral responses in the 550-1085 g/cm2 atmospheric slant depth range and near vertical muon truncated size spectra detected by the GAMMA array.

  5. The dialectic in becoming a mother: experiencing a postpartum phenomenon.

    PubMed

    Sethi, S

    1995-01-01

    In this study of the phenomenon of the postpartum period grounded theory methodology was used to investigate the experiences of first-time mothers during the first three months following their deliveries. The sample consisted of 12 primipara women and 3 multipara women. The data were generated by using unstructured interviews and field notes. Each woman was interviewed twice, the first time between 2 and 3 weeks postpartum, and the second time between 10 and 12 weeks postpartum. The final data for analysis consisted of: data generated through interviews, field notes, and the narratives of four mothers found in the non-fiction literature. Constant comparative analysis resulted in the generation of four categories and corresponding subcategories. These were: (1) Giving of Self; (2) Redefining Self; (3) Redefining Relationships; and (4) Redefining Professional Goals. The categories were not mutually exclusive. All the categories converged to provide support for the core variable 'Dialectic in Becoming a Mother'. The dialectic perspective demonstrated that, in becoming mothers, the women experienced transition, contradictions, tensions and transformations. A theoretical model was developed to show relationships among these major concepts. The findings of this study will be useful in effecting change in the provision of care to postpartum women and their families.

  6. A Plant's Response to Gravity as a Wave Guide Phenomenon

    NASA Astrophysics Data System (ADS)

    Wagner, Orvin

    1997-11-01

    Plant experimental data provides a unifying wave theory (W-wave theory) for the growth and development of plants. A plant's response to gravity is an important aspect of this theory. It appears that a plant part is tuned to the angle with which it initially grew with respect to the gravitational field and changes produce correction responses. This is true because the velocity of W-waves (whose standing waves determine plant structure) within plant tissue is found to be different in different directions (angle a) with respect to the gravitational field. I found that there are preferred values of a, namely integral multiples of near 5 degrees for some plants. Conifers apparently are more sensitive to the gravitational field than deciduous trees, in the cases studied, so their structure is determined in more detail by the gravitational field. A plant's response to gravity appears to be a fundamental phenomenon and may provide a new model for gravity that can be experimentally verified in the laboratory. Along these same lines accelerometers placed in plant tissue indicate that plants produce gravity related forces that facilitate sap flow. See the

  7. Cyberbullying: a 21st Century Health Care Phenomenon.

    PubMed

    Carter, Jemica M; Wilson, Feleta L

    2015-01-01

    This study examined bullying and cyberbullying prevalence among 367 adolescents 10 to 18 years of age who were attending schools and community organizations in suburban and urban neighborhoods in the Midwest United States. The correlational design investigated adolescents' daily use of technology that could be used to cyberbully peers, such as cell phones, computers, email, and the Internet. Results showed that 30% of participants had been bullied during school, and 17% had been cyberbullied, with online social networking sites the most common media employed (68%). The majority of participants owned or had access to computers (92%), email accounts (88%), social networking accounts (e.g., Facebook or MySpace) (82%), and cell phones (79%). Daily technology use included an average of two hours on a computer and a median of 71 text messages per day. Logistic regression analysis revealed no significant differences in bullying or cyberbullying prevalence based on location (urban or suburban) or demographic characteristics. Given the substantial presence of cyberbullying and the increase in technology use among adolescents in the 21st century, nurses need knowledge of the phenomenon to plan assessments in clinical practice. Early identification and assessment of cyberbullying victims and perpetrators, and development and implementation of effective interventions are needed to reduce this form of bullying among adolescents.

  8. Room Temperature Ferromagnetic Polymer and the Correlated Anomalous Magnetoresistance Phenomenon

    NASA Astrophysics Data System (ADS)

    Huang, Jinsong; Yang, Bin; Shield, Jeffrey

    2011-03-01

    Organic magnetoresistance (OMAR) has been observed in organic semiconductor devices where resistance can change in a relatively small external magnetic field at room temperature. Since a weak magnetic field is involved, the hyperfine interaction (HFI) is employed to explain OMAR in the reported literatures. None of these issues consider the magnetic properties of the organic semiconductors themselves. However, the we recently discovered that polymer semiconductors, such as poly(3-hexylthiophene) P3HT, can have room temperature (RT) ferromagnetic properties in their crystalline phase and when mixed with phenyl-C61-butyric acid methyl ester (PCBM). Here, we will report the possible correlation between the ferromagnetic property of the P3HT:PCBM and anomalous OMAR phenomenon including the anisotropic and hysteretic OMAR behavior. The magnetic property of the polymer including the anisotropic and photo induced change of magnetism will be also discussed to explore the possible mechanism of the room temperature ferromagnetism.~ This work is partially supported by the NSF MRSEC program at University.

  9. Digital thermography of the fingers and toes in Raynaud's phenomenon.

    PubMed

    Lim, Mie Jin; Kwon, Seong Ryul; Jung, Kyong-Hee; Joo, Kowoon; Park, Shin-Goo; Park, Won

    2014-04-01

    The aim of this study was to determine whether skin temperature measurement by digital thermography on hands and feet is useful for diagnosis of Raynaud's phenomenon (RP). Fifty-seven patients with RP (primary RP, n = 33; secondary RP, n = 24) and 146 healthy volunteers were recruited. After acclimation to room temperature for 30 min, thermal imaging of palmar aspect of hands and dorsal aspect of feet were taken. Temperature differences between palm (center) and the coolest finger and temperature differences between foot dorsum (center) and first toe significantly differed between patients and controls. The area under curve analysis showed that temperature difference of the coolest finger (cutoff value: 2.2℃) differentiated RP patients from controls (sensitivity/specificity: 67/60%, respectively). Temperature differences of first toe (cutoff value: 3.11℃) also discriminated RP patients (sensitivity/specificity: about 73/66%, respectively). A combination of thermographic assessment of the coolest finger and first toe was highly effective in men (sensitivity/specificity : about 88/60%, respectively) while thermographic assessment of first toe was solely sufficient for women (sensitivity/specificity: about 74/68%, respectively). Thermographic assessment of the coolest finger and first toe is useful for diagnosing RP. In women, thermography of first toe is highly recommended.

  10. Cyclic swelling as a phenomenon inherent to biodegradable polyesters.

    PubMed

    Dittrich, Milan; Snejdrova, Eva

    2014-11-01

    The aim of this study is to evaluate and describe the phenomenon and mechanism of the spontaneous cyclic swelling and deswelling of linear and branched aliphatic polyesters in the aqueous medium. The fluctuation of gel volume in one or several cycles as an inherent property of biodegradable and bioerodible materials has not yet been described. We have observed the process at linear and branched polyesters of aliphatic α-hydroxy acids. The period of duration of cycles was in order of hours to days, as influenced by the size of the bodies ranging from 25 to 1000 mg, the temperature in the range of 7°C-42°C, ionic strength, and pH value. The results demonstrated that swelling is accompanied by hydrolysis of ester bonds with the development of small water-soluble osmotically active molecules. After reaching a higher degree of swelling, the obstruction effect of the gel decreases and the diffusion of soluble degradation products from the body to the environment prevails. A decrease in osmotic pressure inside the body and a decrease in the hydrophilic character of the gel matrix result in deswelling by a collapse of the structure, probably due to hydrophobic interactions of nonpolar polyester chains.

  11. The Oral Tolerance as a Complex Network Phenomenon

    PubMed Central

    2015-01-01

    The phenomenon of oral tolerance refers to a local and systemic state of tolerance induced in the gut after its exposure to innocuous antigens. Recent findings have shown the interrelationship between cellular and molecular components of oral tolerance, but its representation through a network of interactions has not been investigated. Our work aims at identifying the causal relationship of each element in an oral tolerance network, and also to propose a phenomenological model that’s capable of predicting the stochastic behavior of this network when under manipulation. We compared the changes of a “healthy” network caused by “knock-outs” (KOs) in two approaches: an analytical approach by the Perron Frobenius theory; and a computational approach, which we describe within this work in order to find numerical results for the model. Both approaches have shown the most relevant immunological components for this phenomena, that happens to corroborate the empirical results from animal models. Besides explain in a intelligible fashion how the components interacts in a complex manner, we also managed to describe and quantify the importance of KOs that hasn’t been empirically tested. PMID:26115356

  12. Raynaud's Phenomenon: A Brief Review of the Underlying Mechanisms.

    PubMed

    Fardoun, Manal M; Nassif, Joseph; Issa, Khodr; Baydoun, Elias; Eid, Ali H

    2016-01-01

    Raynaud's phenomenon (RP) is characterized by exaggerated cold-induced vasoconstriction. This augmented vasoconstriction occurs by virtue of a reflex response to cooling via the sympathetic nervous system as well as by local activation of α2C adrenoceptors (α2C-AR). In a cold-initiated, mitochondrion-mediated mechanism involving reactive oxygen species and the Rho/ROCK pathway, cytoskeletal rearrangement in vascular smooth muscle cells orchestrates the translocation of α2C-AR to the cell membrane, where this receptor readily interacts with its ligand. Different parameters are involved in this spatial and functional rescue of α2C-AR. Of notable relevance is the female hormone, 17β-estradiol, or estrogen. This is consistent with the high prevalence of RP in premenopausal women compared to age-matched males. In addition to dissecting the role of these various players, the contribution of pollution as well as genetic background to the onset and prevalence of RP are also discussed. Different therapeutic approaches employed as treatment modalities for this disease are also highlighted and analyzed. The lack of an appropriate animal model for RP mandates that more efforts be undertaken in order to better understand and eventually treat this disease. Although several lines of treatment are utilized, it is important to note that precaution is often effective in reducing severity or frequency of RP attacks.

  13. Firm Size, a Self-Organized Critical Phenomenon: Evidence from the Dynamical Systems Theory

    NASA Astrophysics Data System (ADS)

    Chandra, Akhilesh

    This research draws upon a recent innovation in the dynamical systems literature called the theory of self -organized criticality (SOC) (Bak, Tang, and Wiesenfeld 1988) to develop a computational model of a firm's size by relating its internal and the external sub-systems. As a holistic paradigm, the theory of SOC implies that a firm as a composite system of many degrees of freedom naturally evolves to a critical state in which a minor event starts a chain reaction that can affect either a part or the system as a whole. Thus, the global features of a firm cannot be understood by analyzing its individual parts separately. The causal framework builds upon a constant capital resource to support a volume of production at the existing level of efficiency. The critical size is defined as the production level at which the average product of a firm's factors of production attains its maximum value. The non -linearity is inferred by a change in the nature of relations at the border of criticality, between size and the two performance variables, viz., the operating efficiency and the financial efficiency. The effect of breaching the critical size is examined on the stock price reactions. Consistent with the theory of SOC, it is hypothesized that the temporal response of a firm breaching the level of critical size should behave as a flicker noise (1/f) process. The flicker noise is characterized by correlations extended over a wide range of time scales, indicating some sort of cooperative effect among a firm's degrees of freedom. It is further hypothesized that a firm's size evolves to a spatial structure with scale-invariant, self-similar (fractal) properties. The system is said to be self-organized inasmuch as it naturally evolves to the state of criticality without any detailed specifications of the initial conditions. In this respect, the critical state is an attractor of the firm's dynamics. Another set of hypotheses examines the relations between the size and the

  14. Urban Heat Island phenomenon in extreme continental climate (Astana, Kazakhstan)

    NASA Astrophysics Data System (ADS)

    Konstantinov, Pavel; Akhmetova, Alina

    2015-04-01

    Urban Heat Island (UHI) phenomenon is well known in scientific literature since first half of the 19th century [1]. By now a wide number of world capitals is described from climatological point of view, especially in mid-latitudes. In beginning of XXI century new studies focus on heat island of tropical cities. However dynamics UHI in extreme continental climates is insufficiently investigated, due to the fact that there isn't large cities in Europe and Northern America within that climate type. In this paper we investigate seasonal and diurnal dynamics UHI intensity for Astana, capital city of Kazakhstan (population larger than 835 000 within the city) including UHI intensity changes on different time scales. Now (since 1998) Astana is the second coldest capital city in the world after Ulaanbaatar, Mongolia [3] For this study we use the UHI investigation technology, described in [2]. According to this paper, we selected three stations: one located into city in high and midrise buildings area (including extensive lowrise and high-energy industrial - LCZ classification) and two others located in rural site (sparsely built or open-set and lightweight lowrise according LCZ classification). Also these stations must be close by distance (less than 100 km) and altitude. Therefore, first for Astana city were obtained numerical evaluations for UHI climate dynamics, UHI dependence of synoptic situations and total UHI climatology on monthly and daily averages. References: 1.Howard, L. (1833) The Climate of London, Deduced from Meteorological Observations. Volume 2, London. 2.Kukanova E.A., Konstantinov P.I. An urban heat islands climatology in Russia and linkages to the climate change In Geophysical Research Abstracts, volume 16 of EGU General Assembly, pages EGU2014-10833-1, Germany, 2014. Germany. 3.www.pogoda.ru.net

  15. Optical observations of the beam-plasma discharge phenomenon

    NASA Technical Reports Server (NTRS)

    Sivjee, G. G.; Hamwey, R. M.; Hallinan, T. J.

    1993-01-01

    Spectroscopic observations of optical emissions from the beam-plasma discharge (BPD) phenomenon were made with NASA's vacuum chamber facility, at the Johnson Space Center, configured to simulate the physical conditions of magnetospheric electron beam injection into the ionospheric/upper-atmospheric environment. Nonlinear N2 and N2(+) optical emission growth rates (with respect to incremental electron beam current values) were observed from the chamber gas during transition to the BPD state. For electron-beam currents (I) near the BPD transition value (I(sub c)), the band emissions from the chamber gas produced by relatively low energy (less than or equal to 50 eV) electrons interacting with N2 were anomalously more intense than those requiring higher energy (greater than 100 eV) electrons to excite them. For I more greater than I(sub c), the optical emissions increased linearly with I (as was the case for I less than I(sub c)) and their ratios decreased significantly from the peak values attained when I approximately equals I(sub c). These observations suggest that during BPD some of the energy of the primary electron beam is efficiently transferred, via wave-particle interactions, to local electrons produced through ionization of the chamber gas; the resulting suprathermal electrons provide an additional source of excitation for the relatively low energy states (A, B and C) of N2. Such nonlinear excitation of upper atmospheric gas may occur in certain auroral events wherein the current due to the precipitating electrons approaches a value close to I(sub c).

  16. A proposal to describe a phenomenon of expanding language

    NASA Astrophysics Data System (ADS)

    Swietorzecka, Kordula

    Changes of knowledge, convictions or beliefs are subjects of interest in frame of so called epistemic logic. There are various proposed descriptions of a process (or its results) in which so a called agent may invent certain changes in a set of sentences that he had already chosen as a point of his knowledge, convictions or beliefs (and this is also considered in case of many agents). In the presented paper we are interested in the changeability of an agent's language which is by its own independent from already mentioned changes. Modern epistemic formalizations assume that the agent uses a fixed (and so we could say: static) language in which he expresses his various opinions which may change. Our interest is to simulate a situation when a language is extended by adding to it new expressions which were not known by the agent so he couldn't even consider them as subjects of his opinions. Actually such a phenomenon happens both in natural and scientific languages. Let us mention a fact of expanding languages in process of learning or in result of getting of new data about some described domain. We propose a simple idealization of extending sentential language used by one agent. Actually the language is treated as a family of so called n-languages which get some epistemic interpretation. Proposed semantics enables us to distinguish between two different types of changes - these which occur because of changing agent's convictions about logical values of some n-sentences - we describe them using one place operator C to be read it changes that - and changes that consist in increasing the level of n-language by adding to it new expressions. However the second type of change - symbolized by variable G - may be also considered independently of the first one. The logical frame of our considerations comes from and it was originally used to describe Aristotelian theory of substantial changes. This time we apply the mentioned logic in epistemology.

  17. International consensus criteria for the diagnosis of Raynaud's phenomenon.

    PubMed

    Maverakis, Emanual; Patel, Forum; Kronenberg, Daniel G; Chung, Lorinda; Fiorentino, David; Allanore, Yannick; Guiducci, Serena; Hesselstrand, Roger; Hummers, Laura K; Duong, Chris; Kahaleh, Bashar; Macgregor, Alexander; Matucci-Cerinic, Marco; Wollheim, Frank A; Mayes, Maureen D; Gershwin, M Eric

    2014-01-01

    Vasoconstriction accompanied by changes in skin color is a normal physiologic response to cold. The distinction between this normal physiology and Raynaud's phenomenon (RP) has yet to be well characterized. In anticipation of the 9th International Congress on Autoimmunity, a panel of 12 RP experts from 9 different institutes and four different countries were assembled for a Delphi exercise to establish new diagnostic criteria for RP. Relevant investigators with highly cited manuscripts in Raynaud's-related research were identified using the Web of Science and invited to participate. Surveys at each stage were administered to participants via the on-line SurveyMonkey software tool. The participants evaluated the level of appropriateness of statements using a scale of 1 (extremely inappropriate) through 9 (extremely appropriate). In the second stage, panel participants were asked to rank rewritten items from the first round that were scored as "uncertain" for the diagnosis of RP, items with significant disagreement (Disagreement Index > 1), and new items suggested by the panel. Results were analyzed using the Interpercentile Range Adjusted for Symmetry (IPRAS) method. A 3-Step Approach to diagnose RP was then developed using items the panelists "agreed" were "appropriate" diagnostic criteria. In the final stage, the panel was presented with the newly developed diagnostic criteria and asked to rate them against previous models. Following the first two iterations of the Delphi exercise, the panel of 12 experts agreed that 36 of the items were "appropriate", 12 items had "uncertain" appropriateness, and 13 items were "inappropriate" to use in the diagnostic criteria of RP. Using an expert committee, we developed a 3-Step Approach for the diagnosis of RP and 5 additional criteria for the diagnosis of primary RP. The committee came to an agreement that the proposed criteria were "appropriate and accurate" for use by physicians to diagnose patients with RP.

  18. Car surfing: case studies of a growing dangerous phenomenon.

    PubMed

    Clark, Steven; Mangram, Alicia; Dunn, Ernest

    2008-03-01

    Car surfing is a dangerous new pastime for American youth. Car surfing is an activity that is defined as standing (or lying) on a vehicle while it is being driven. This activity frequently results in severe injuries that often require significant surgical intervention. Despite its destructive nature, however, there are many Internet sites that encourage this behavior and view it as amusing. As a result, car surfing is becoming increasingly popular. We conducted a retrospective chart review of all patients injured as a result of car surfing over the last 4 years at our Urban Level II trauma center. Data collected included Injury Severity Score (ISS), Revised Trauma Score (RTS), age, gender, injury pattern, surgical intervention, and length of stay. Eight car surfers were identified. The average age was 17. The average Revised Trauma Score was 6.8 with an average Injury Severity Score of 16.9. Five patients were admitted to the intensive care unit. Four of these five patients needed to be intubated for ventilatory support. Five of the eight patients had significant intracranial injuries. Two patients had epidural hematomas that required evacuation. Two other patients had subdural hematomas that were treated nonoperatively, and one patient had a subarachnoid hemorrhage that was also treated nonoperatively. Four of the eight patients required surgical intervention. There were no deaths in this study. Car surfing leads to severe injuries that can result in significant morbidity. American youth have access to Internet sites that project this activity as an acceptable behavior. Five of our eight patients had a significant intracranial injury. Trauma surgeons need to be more aware of this injury phenomenon.

  19. Virulence conversion of Legionella pneumophila: a one-way phenomenon.

    PubMed Central

    Catrenich, C E; Johnson, W

    1988-01-01

    Previous investigations have shown that Legionella pneumophila converts from virulence to avirulence after passage on supplemented Mueller-Hinton (SMH) agar and may convert back to virulence after passage in guinea pigs. However, there is no additional information concerning the apparent interconversion of virulent and avirulent derivatives of L. pneumophila cultures. We investigated the stability of a parental virulent culture and its avirulent derivatives and the growth and viability of these cultures on charcoal-yeast extract (CYE) and SMH agars. Avirulent derivatives of a highly virulent L. pneumophila culture were obtained by passage of the virulent parent culture on SMH agar. The only time a virulent L. pneumophila culture was recoverable from an avirulent culture was when the avirulent culture was derived from a saline suspension of a virulent culture which had been passaged only five times on SMH agar. When an avirulent culture was derived from a virulent culture passaged 25 times on SMH agar or from an isolated colony which grew on a SMH agar plate, we were unable to recover a virulent culture after successive passage through guinea pigs. These results suggest that the conversion process which occurs between virulent and avirulent forms of L. pneumophila is a one-way phenomenon from virulence to avirulence and that stable avirulent derivatives can be isolated. Furthermore, our findings suggest that SMH agar acts as a selective medium for the growth of avirulent L. pneumophila, and growth on SMH agar may be a phenotypic marker for avirulence. Virulent cells, although unable to grow on SMH agar, may remain viable for several passages on SMH agar and propagate when inoculated into guinea pigs. Images PMID:3182073

  20. Understanding atomistic phenomenon for hydrogen storage in complex metal hydrides

    NASA Astrophysics Data System (ADS)

    Chopra, Irinder Singh

    The storage of hydrogen into metals in the form of complex metal hydrides is one of the most promising methods. However, the incorporation and release of hydrogen requires very high temperatures. The discovery that the addition of Ti compounds lowers NaAlH4 decomposition barriers closer to ambient conditions, has re-ignited the field, and it is believed that surface processes are responsible for H2 dissociation and mass transport required to form the hydrogenated materials. Such surface reactions mechanisms are however difficult to study with typical spectroscopic and imaging surface science tools. Alanes lack contrast under electron microscopes and can modify the Scanning Tunneling Microscopy (STM) tips. Infrared spectroscopy would be a sensitive probe to investigate the adsorption of hydrogen providing, but has so far failed to detect chemisorbed hydrogen on Ti-doped Al surfaces due to the weak Al-H dynamic dipole moment. Thus despite extensive investigations, the fundamental mechanisms of the role of Ti and alane formation have remained elusive. In this study combining surface infrared (IR) spectroscopy and density functional theory (DFT), we provide atomistic details about the role of Ti as a catalyst for hydrogen uptake and alane formation and evolution on single crystal Al(111) and Al(100) surfaces. We are able to detect H indirectly by using CO as a probe molecule of the weak Al-H species. We demonstrate that aluminum doped with very small amounts of titanium (in a specific configuration) can activate molecular hydrogen at temperatures as low as 90K. Once dissociated, hydrogen spills over from these catalytic sites on to the Al surface and protects the surface from further reactions. We also show that, on Ti-doped Al surfaces, the diffusion dynamics are severely altered by Ti doping (Atomic hydrogen and AlH3 are trapped at the Ti sites) as indicated by a marked decrease of higher alane concentrations, which is deleterious for hydrogen storage for which mass

  1. Deviation from Power Law Behavior in Landslide Phenomenon

    NASA Astrophysics Data System (ADS)

    Li, L.; Lan, H.; Wu, Y.

    2013-12-01

    behavior in landslide phenomenon. Figure shows that a rollover of landslide size distribution in the small size end is produced as the probability for V/S (the failure volume to failure surface ratio of landslide) exceeding the mechanical threshold applied to the power law distribution of landslide volume.

  2. MHD Dynamo phenomenon in our lab (Petrus Peregrinus Medal Lecture)

    NASA Astrophysics Data System (ADS)

    Gailitis, Agris

    2016-04-01

    Celestial objects generate magnetic field very like technical dynamo do. Field induces current in a moving electroconductor. The induced current amplifies magnetic field. At large enough product conductivity time's velocity time's size amplification exceeds losses and situation without magnetic field is impossible. Such scenario is obvious for technical dynamo made from insolated wire but not so for uniform conductor as in celestial bodies. Development of the idea took literally the entire 20th century. Discovery of sunspot magnetic fields at the century rise and laboratory verification at the very fall. At thirties Cowling noticed that geometrically simple shaped (axially symmetrical) field can't sustain itself. Process must be more complex, somehow spatially fragmented. At the middle of century Parker and Steenbeck saw such fragmentation in a turbulent structure of hydrodynamic flow. Shortly after his α-effect approach was made ready Steenbeck invited us to think on molten Na experiments for theory verification. The first idea was to push the Na flow through the hand-blown pipe maze. Similar industrial scale experiment after years and regardless of us was realized in Karlsruhe. Seeking for something cheaper we stopped at Ponomarenko idea - axially symmetric helical flow can't generate axi-simmetric field but it can generate azimuthally structured one. The mathematical model was modified to experimental conditions and numerically optimized. The Dynamo stand was built and it works. Even after optimization Dynamo stand exceeds usual size of hydraulic experiments. 2m3 of molten Na circulate there by means of propeller powered from 200kW motor. When circulation exceeds 0.6 m3/s (at 120°C) seemingly from nowhere appears magnetic field. Twisted field pattern slowly (about 1.5Hz) rotates round flow axis. Up to 0.1T field stay as long as stay circulation and temperature. When sodium is heated up or slowed down the field is slowly dying out. Phenomenon is much richer

  3. Local hyperemia to heating is impaired in secondary Raynaud's phenomenon.

    PubMed

    Boignard, Aude; Salvat-Melis, Muriel; Carpentier, Patrick H; Minson, Christopher T; Grange, Laurent; Duc, Catherine; Sarrot-Reynauld, Françoise; Cracowski, Jean-Luc

    2005-01-01

    Accurate and sensitive measurement techniques are a key issue in the quantification of the microvascular and endothelial dysfunction in systemic sclerosis (SSc). Thermal hyperemia comprises two separate mechanisms: an initial peak that is axon reflex mediated; and a sustained plateau phase that is nitric oxide dependent. The main objective of our study was to test whether thermal hyperemia in patients with SSc differed from that in patients with primary Raynaud's phenomenon (RP) and healthy controls. In a first study, we enrolled 20 patients suffering from SSc, 20 patients with primary RP and 20 healthy volunteers. All subjects were in a fasting state. Post-occlusive hyperemia, 0.4 mg sublingual nitroglycerin challenge and thermal hyperemia were performed using laser Doppler flowmetry on the distal pad of the third left finger. In a second study, thermal hyperemia was performed in 10 patients with rheumatoid arthritis and 10 patients with primary RP. The thermal hyperemia was dramatically altered in terms of amplitude and kinetics in patients with SSc. Whereas 19 healthy volunteers and 18 patients with primary RP exhibited the classic response, including an initial peak within the first 10 minutes followed by a nadir and a second peak, this occurred only in four of the SSc patients (p < 0.0001). The 10 minutes thermal peak was 43.4 (23.2 to 63), 42.6 (31 to 80.7) and 27 (14.7 to 51.4) mV/mm Hg in the healthy volunteers, primary RP and SSc groups, respectively (p = 0.01), while the 44 degrees C thermal peak was 43.1 (21.3 to 62.1), 42.6 (31.6 to 74.3) and 25.4 (15 to 52.4) mV/mm Hg, respectively (p = 0.01). Thermal hyperemia was more sensitive and specific than post-occlusive hyperhemia for differentiating SSc from primary RP. In patients with rheumatoid arthritis, thermal hyperemia was also altered in terms of amplitude. Thermal hyperemia is dramatically altered in patients with secondary RP in comparison with subjects with primary RP. Further studies are required

  4. "Thermal Charging" Phenomenon in Electrical Double Layer Capacitors.

    PubMed

    Wang, Jianjian; Feng, Shien-Ping; Yang, Yuan; Hau, Nga Yu; Munro, Mary; Ferreira-Yang, Emerald; Chen, Gang

    2015-09-09

    Electrical double layer capacitors (EDLCs) are usually charged by applying a potential difference across the positive and negative electrodes. In this paper, we demonstrated that EDLCs can be charged by heating. An open circuit voltage of 80-300 mV has been observed by heating the supercapacitor to 65 °C. The charge generated at high temperature can be stored in the device after its returning to the room temperature, thus allowing the lighting up of LEDs by connecting the "thermally charged" supercapacitors in a series. The underlying mechanism is related to a thermo-electrochemical process that enhances the kinetics of Faradaic process at the electrode surface (e.g., surface redox reaction of functional group, or chemical adsorption/desorption of electrolyte ions) at higher temperature. Effects of "thermal charging" times, activation voltage, rate, and times on "thermally charged" voltage are studied and possible mechanisms are discussed.

  5. [The phenomenon of gene linkage and recombination in the paternity test].

    PubMed

    Cheng, D L; Yan, P H; Liu, Y; Chen, J

    1999-02-01

    The phenomenon of gene linkage and recombination may nearly be overlooked in paternity test of one single child, but it is likely encountered in paternity test of twin or more. In a case of paternity test, the results of 17 items including eight DNA loci were analyzed and the phenomenon of gene linkage and recombination was discussed in detail. This phenomenon should be brought into necessary attention in the paternity test.

  6. Clinical and image improvement of Raynaud's phenomenon after botulinum toxin type A treatment.

    PubMed

    Zhao, HongMei; Lian, YaJun

    2015-08-01

    Raynaud's phenomenon is often accompanied by pain, digital ulceration and compromised daily activities. Pharmacological therapy or sympathectomies have been administered to diminish these symptoms but existing treatments are not invariably efficacious. A recent case series has described the use of botulinum toxin type A in the treatment of Raynaud's phenomenon. We report two patients with severe or mild Raynaud's phenomenon who were injected with BTX-A; both of whom experienced clinical and image improvement after treatment.

  7. Synthesis of Phenyl-Adducted Cyclodextrin through the Click Reaction

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A new derivative of ß-cyclodextrin (CD) has been made incorporating the phenyl group through the use of click reaction. The resulting product exhibits a self-association phenomenon through the formation of inclusion compound between the phenyl group and CD. The product has been characterized by 1H...

  8. Mercury Cavitation Phenomenon in Pulsed Spallation Neutron Sources

    SciTech Connect

    Futakawa, Masatoshi; Naoe, Takashi; Kawai, Masayoshi

    2008-06-24

    Innovative researches will be performed at Materials and Life Science Experimental Facility in J-PARC, in which a mercury target system will be installed as MW-class pulse spallation neutron sources. Proton beams will be injected into mercury target to induce the spallation reaction. At the moment the intense proton beam hits the target, pressure waves are generated in the mercury because of the abrupt heat deposition. The pressure waves interact with the target vessel leading to negative pressure that may cause cavitation along the vessel wall. Localized impacts by micro-jets and/or shock waves which are caused by cavitation bubble collapse impose pitting damage on the vessel wall. The pitting damage which degrades the structural integrity of target vessels is a crucial issue for high power mercury targets. Micro-gas-bubbles injection into mercury may be useful to mitigate the pressure wave and the pitting damage. The visualization of cavitation-bubble and gas-bubble collapse behaviors was carried out by using a high-speed video camera. The differences between them are recognized.

  9. Catalysis of Photochemical Reactions.

    ERIC Educational Resources Information Center

    Albini, A.

    1986-01-01

    Offers a classification system of catalytic effects in photochemical reactions, contrasting characteristic properties of photochemical and thermal reactions. Discusses catalysis and sensitization, examples of catalyzed reactions of excepted states, complexing ground state substrates, and catalysis of primary photoproducts. (JM)

  10. Anaphylaxis-Like Reactions

    MedlinePlus

    ... Home Conditions Anaphylaxis Anaphylaxis-Like Reactions Anaphylaxis-Like Reactions Make an Appointment Refer a Patient Ask a ... exposed to a foreign substance, some people suffer reactions identical to anaphylaxis, but no allergy (IgE antibody) ...

  11. [Suppressive effects of lanoconazole on arthus phenomenon in vivo and on production and functions of TNF in vitro].

    PubMed

    Mitsuya, M; Wada, K; Ishibashi, H; Tansho, S; Abe, S; Yamaguchi, H

    2000-01-01

    The anti-inflammatory effect of lanoconazole (LCZ) was investigated in vivo and in vitro. The effect of LCZ was evaluated on the inflammatory reactions elicited by intradermal injection of ovalbumin to ovalbumin-immunized rabbits, as an Arthus phenomenon. A one or two % cream preparation of LCZ was topically applied on the lesion daily after challenging injection until the inflamation had diminished. By macroscopic observation and measuring the diameter of edema, erythema, hemorrhage and necrosis, the effects of LCZ on the reactions were compared with the reactions of the sites administered withcream vehicle as reference agent. Two % LCZ showed an anti-hemorrhagic effect. The in vitro effect of LCZ on production and functions of an inflammatory cytokine, TNF was also examined. LCZ suppressed the production of TNF by murine peritoneal macrophages at 20 micro g/ml and the adhesion of neutrophils at 100 micro g/ml. Moreover, LCZ significantly suppressed the growth inhibitory activity of TNF against L929 fibroblasts at 0.5 micro g/ml. A very low concentration of LCZ might protect the fibroblasts from immunological cytotoxicity in vivo. These findings suggest that LCZ has a suppressive activity to inflammatory responses and this suppressive action may be due to its protective activity to cells like fibroblasts.

  12. Children's Independent Exploration of a Natural Phenomenon by Using a Pictorial Computer-Based Simulation.

    ERIC Educational Resources Information Center

    Kangassalo, Marjatta

    Using a pictorial computer simulation of a natural phenomenon, children's exploration processes and their construction of conceptual models were examined. The selected natural phenomenon was the variations of sunlight and heat of the sun experienced on the earth in relation to the positions of the earth and sun in space, and the subjects were…

  13. Diffusion phenomenon for linear dissipative wave equations in an exterior domain

    NASA Astrophysics Data System (ADS)

    Ikehata, Ryo

    Under the general condition of the initial data, we will derive the crucial estimates which imply the diffusion phenomenon for the dissipative linear wave equations in an exterior domain. In order to derive the diffusion phenomenon for dissipative wave equations, the time integral method which was developed by Ikehata and Matsuyama (Sci. Math. Japon. 55 (2002) 33) plays an effective role.

  14. The Role of Photographs and Films in Kettlewell's Popularizations of the Phenomenon of Industrial Melanism.

    ERIC Educational Resources Information Center

    Rudge, David Wyss

    2003-01-01

    Discusses why public perceptions of the importance of Kettlewell's investigations on the phenomenon of industrial melanism diverge from those of researchers who actually work on the phenomenon. Explains the important role photographic and film depictions of differential bird predation play in Kettlewell's popularizations. (Author/SOE)

  15. A Gadamerian Investigation of the Two Cultures Phenomenon in an Undergraduate Honors Research Fellowship

    ERIC Educational Resources Information Center

    Giazzoni, Michael J.

    2009-01-01

    The Two Cultures phenomenon, first given its name by C. P. Snow in 1956, consists of a conflict between participants in the academic communities of the natural sciences and the humanities; it also mirrors the methodological debate in the social sciences. This phenomenon also occurs in undergraduates in an interdisciplinary research fellowship at…

  16. A New Phenomenon in Saudi Females' Code-Switching: A Morphemic Analysis

    ERIC Educational Resources Information Center

    Turjoman, Mona O.

    2016-01-01

    This sociolinguistics study investigates a new phenomenon that has recently surfaced in the field of code-switching among Saudi females residing in the Western region of Saudi Arabia. This phenomenon basically combines bound Arabic pronouns, tense markers or definite article to English free morphemes or the combination of bound English affixes to…

  17. The Stroop Phenomenon and Its Use in the Study of Perceptual, Cognitive and Response Processes.

    ERIC Educational Resources Information Center

    Dyer, Frederick N.

    The review summarizes empirical findings and theoretical views related to the Stroop color-word phenomenon, in which naming of a color is disrupted and delayed by the presence of an "irrelevant" word denoting a color different from the color patch. It was deemed important to increase awareness of this phenomenon, since it involves basic…

  18. Partial fingertip necrosis following a digital surgical procedure in a patient with primary Raynaud's phenomenon.

    PubMed

    Uygur, Safak; Tuncer, Serhan

    2014-12-01

    Raynaud's phenomenon is a common clinical disorder consisting of recurrent, long-lasting and episodic vasospasm of the fingers and toes often associated with exposure to cold. In this article, we present a case of partial fingertip necrosis following digital surgical procedure in a patient with primary Raynaud's phenomenon.

  19. On the cause of the flat-spot phenomenon observed in silicon solar cells at low temperatures and low intensities

    NASA Technical Reports Server (NTRS)

    Weizer, V. G.; Broder, J. D.; Brandhorst, H. W., Jr.; Forestieri, A. F.

    1982-01-01

    A model is presented that explains the "flat-spot" (FS) power loss phenomenon observed in silicon solar cells operating deep space (low temperature, low intensity) conditions. Evidence is presented suggesting that the effect is due to localized metallurgical interactions between the silicon substrate and the contact metallization. These reactions are shown to result in localized regions in which the PN junction is destroyed and replaced with a metal-semiconductor-like interface. The effects of thermal treatment, crystallographic orientation, junction depth, and metallurization are presented along with a method of preventing the effect through the suppression of vacancy formation at the free surface of the contact metallization. Preliminary data indicating the effectiveness of a TiN diffusion barrier in preventing the effect are also given.

  20. Skin reactions to sunscreens.

    PubMed

    Nixon, R L; Frowen, K E; Lewis, A E

    1997-06-01

    Sunscreen reactions are said not to be uncommon. A population referred to a patch testing clinic was evaluated for reactions to sunscreen by questionnaire initially and then, if relevant, by patch testing to sunscreen products and their components. Irritant reactions were more common than allergic contact dermatitis. Allergic reactions to sunscreens were less common than to non-sunscreen chemicals present in sunscreen products.

  1. The Glyoxal Clock Reaction

    ERIC Educational Resources Information Center

    Ealy, Julie B.; Negron, Alexandra Rodriguez; Stephens, Jessica; Stauffer, Rebecca; Furrow, Stanley D.

    2007-01-01

    Research on the glyoxal clock reaction has led to adaptation of the clock reaction to a general chemistry experiment. This particular reaction is just one of many that used formaldehyde in the past. The kinetics of the glyoxal clock makes the reaction suitable as a general chemistry lab using a Calculator Based Laboratory (CBL) or a LabPro. The…

  2. Statistical significance of the rich-club phenomenon in complex networks

    NASA Astrophysics Data System (ADS)

    Jiang, Zhi-Qiang; Zhou, Wei-Xing

    2008-04-01

    We propose that the rich-club phenomenon in complex networks should be defined in the spirit of bootstrapping, in which a null model is adopted to assess the statistical significance of the rich-club detected. Our method can serve as a definition of the rich-club phenomenon and is applied to analyze three real networks and three model networks. The results show significant improvement compared with previously reported results. We report a dilemma with an exceptional example, showing that there does not exist an omnipotent definition for the rich-club phenomenon.

  3. Robotic-Assisted Laparoscopic Donor Nephrectomy of Patient With Nutcracker Phenomenon.

    PubMed

    Barman, Naman; Palese, Michael

    2016-05-17

    We report the case of a 30-year-old male patient undergoing a robotic-assisted laparoscopic left donor nephrectomy, where compression of the left renal vein between the superior mesenteric artery and aorta was noted on magnetic resonance angiography before the operation. The patient was diagnosed with nutcracker phenomenon and was noted to be asymptomatic at that time. This is the first reported case to date of a patient with nutcracker phenomenon who underwent a robotic-assisted laparoscopic donor nephrectomy. This article also reviews the current literature on nutcracker phenomenon and nutcracker syndrome.

  4. [Vibration-induced Raynaud phenomenon caused by an electric hedge trimmer].

    PubMed

    Kákosy, T; Martin, J; Zentai, N; Székely, A

    1995-08-06

    Authors observed Raynaud's phenomenon verified by cold-provocation test and measuring finger systolic blood pressure on a man working with bush cutter equipment installed on a tractor. Vibration measurements showed acceleration superior to maximal allowable level. Other causes of a secondary Raynaud's phenomenon were excluded by means of detailed internal examination. On the ground of the exposure data and lack of other ethiological factors the authors think that the patient had vibration-induced Raynaud's phenomenon. For prevention they proposed the diminishing of the daily exposure time and periodical medical examinations. They want to draw the attention for this sort of exposure.

  5. Effect of acid and temperature on the discontinuous shear thickening phenomenon of silica nanoparticle suspensions

    NASA Astrophysics Data System (ADS)

    Li, Shuangbing; Wang, Jixiao; Cai, Wei; Zhao, Song; Wang, Zhi; Wang, Shichang

    2016-08-01

    The discontinuous shear thickening (DST) phenomenon of silica nanoparticle suspensions was investigated in this article. First, the non-aggregated silica nanoparticles were synthesized and characterized. The results indicate that the silica nanoparticles are spherical particles with a narrow size distribution with a diameter of approximately 90 nm. Next, the influence of nitric acid concentration and temperature on the DST phenomenon of shear thickening fluids (STFs) was investigated. The results indicate that the concentrated fluids with nitric acid concentration below 8.50 mmol/L and at a temperature below 40 °C exhibit a readily noticeable DST phenomenon.

  6. The Psychological Essence of the Child Prodigy Phenomenon: Sensitive Periods and Cognitive Experience.

    ERIC Educational Resources Information Center

    Shavinina, Larisa V.

    1999-01-01

    Examination of the child prodigy phenomenon suggests it is a result of extremely accelerated mental development during sensitive periods that leads to the rapid growth of a child's cognitive resources and their construction into specific exceptional achievements. (Author/DB)

  7. Ringing phenomenon in chaotic microcavity for high-speed ultra-sensitive sensing

    PubMed Central

    Chen, Lei; Liu, Qian; Zhang, Wei-Gang; Chou, Keng C.

    2016-01-01

    The ringing phenomenon in whispering-gallery-mode (WGM) microcavities has demonstrated its great potential for highly-sensitive and high-speed sensing. However, traditional symmetric WGM microcavities have suffered from an extremely low coupling efficiency via free-space coupling because the emission of symmetric WGMs is non-directional. Here we report a new approach for high-speed ultra-sensitive sensing using the ringing phenomenon in a chaotic regime. By breaking the rotational symmetry of a WGM microcavity and introducing chaotic behaviors, we show that the ringing phenomenon in chaotic WGM microcavities extends over both the positive and the negative frequency detune, allowing the ringing phenomenon to interact with analytes over a much broader bandwidth with a reduced dead time. Because the coupling of the chaotic microcavity is directional, it produces a significantly higher signal output, which improves its sensitivity without the need of a fiber coupler. PMID:27966591

  8. The preferential flow of soil: A widespread phenomenon in pedological perspectives

    NASA Astrophysics Data System (ADS)

    Zhang, Yinghu; Zhang, Mingxiang; Niu, Jianzhi; Zheng, Haijin

    2016-06-01

    The article provides an overview of studies about the preferential flow phenomenon. This phenomenon is one of the types of the transportation of water solution through the soil profile by preferential channels (pathways) with a relatively high speed and with a slight change in the chemical composition of the solution. Interest in this phenomenon has risen sharply in the last two decades due to the observed fast transportation of contaminants from soil surface into groundwater level. On the basis of the literature data, the authors give the definition of this phenomenon, consider its types, degree, features, mechanisms, methods and models and research perspectives, in particular the interaction between preferential flow and soil matrix flow. The article considers the aspects of the movement of soil water carrying heavy metals and pesticides; hence, it concerns the protection of environment and people's health. It provides the thorough review of the studies on the preferential flow, and describes the research directions and their development.

  9. Intraoperative Anaphylactic Reaction: Is it the Floseal?

    PubMed Central

    Martin, David; Schloss, Brian; Beebe, Allan; Samora, Walter; Klamar, Jan; Stukus, David; Tobias, Joseph D.

    2016-01-01

    When hemodynamic or respiratory instability occurs intraoperatively, the inciting event must be determined so that a therapeutic plan can be provided to ensure patient safety. Although generally uncommon, one cause of cardiorespiratory instability is anaphylactic reactions. During anesthetic care, these most commonly involve neuromuscular blocking agents, antibiotics, or latex. Floseal is a topical hemostatic agent that is frequently used during orthopedic surgical procedures to augment local coagulation function and limit intraoperative blood loss. As these products are derived from human thrombin, animal collagen, and animal gelatin, allergic phenomenon may occur following their administration. We present 2 pediatric patients undergoing posterior spinal fusion who developed intraoperative hemodynamic and respiratory instability following use of the topical hemostatic agent, Floseal. Previous reports of such reactions are reviewed, and the perioperative care of patients with intraoperative anaphylaxis is discussed. PMID:27713677

  10. Microscale Thermite Reactions.

    ERIC Educational Resources Information Center

    Arnaiz, Francisco J.; Aguado, Rafael; Arnaiz, Susana

    1998-01-01

    Describes the adaptation of thermite (aluminum with metal oxides) reactions from whole-class demonstrations to student-run micro-reactions. Lists detailed directions and possible variations of the experiment. (WRM)

  11. Microfluidic chemical reaction circuits

    SciTech Connect

    Lee, Chung-cheng; Sui, Guodong; Elizarov, Arkadij; Kolb, Hartmuth C; Huang, Jiang; Heath, James R; Phelps, Michael E; Quake, Stephen R; Tseng, Hsian-rong; Wyatt, Paul; Daridon, Antoine

    2012-06-26

    New microfluidic devices, useful for carrying out chemical reactions, are provided. The devices are adapted for on-chip solvent exchange, chemical processes requiring multiple chemical reactions, and rapid concentration of reagents.

  12. Allergic reactions (image)

    MedlinePlus

    Allergic reaction is a sensitivity to a specific substance, called an allergen, that is contacted through the skin, inhaled into the lungs, swallowed or injected. The body's reaction to an allergen can be mild, such as ...

  13. Allergic reactions (image)

    MedlinePlus

    Allergic reaction can be provoked by skin contact with poison plants, chemicals and animal scratches, as well as by ... dust, nuts and shellfish, may also cause allergic reaction. Medications such as penicillin and other antibiotics are ...

  14. 'Time slip' phenomenon in adolescents and adults with autism spectrum disorders: case series.

    PubMed

    Tochimoto, Shinnichi; Kurata, Koichi; Munesue, Toshio

    2011-06-01

    In recent years, it has been noticed that adolescent and adult patients with autism spectrum disorder (ASD) sometimes visit psychiatric medical institutions. In some cases, these patients commit an act of violence and are dealt with by psychiatric emergency and forensic psychiatric services. In this report, we present two cases with ASD who visited a psychiatric emergency service because of the 'time slip' phenomenon, and discuss the clinical significance of this phenomenon.

  15. The problem of moral motivation and the happy victimizer phenomenon: killing two birds with one stone.

    PubMed

    Minnameier, Gerhard

    2010-01-01

    One surprising feature of cognitive and emotional development in the moral domain is the so-called happy victimizer phenomenon, which is commonly explained by a lack of moral motivation. Concerning this general approach, there are two pieces of news in this chapter. The bad news is that moral motivation is a highly problematic concept and its purported theoretical role in moral functioning untenable. The good news is that the happy victimizer phenomenon can be explained without reference to something like "moral motivation."

  16. Continuous-Wave Laser Beam Fanning in Organic Solutions: A Novel Phenomenon

    NASA Technical Reports Server (NTRS)

    Abdeldayem, Hossin; Witherow, William K.; Shields, Angela; Penn, Benjamin; Frazier, Donald O.; Moghbel, Mehdi; Venkateswarlu, P.; Sekhar, P. Chandra; George, M. C.

    1994-01-01

    If a low-power cw Ar(+) laser beam (approx. 50 mW) is sent horizontally and focused on the entrance side of a cuvette containing an absorptive solution, the beam fans into the lower half of the cuvette instead of propagating through and forming self-phase-modulation fringes. We call this phenomenon self-beam fanning, which has been observed in several organic solutions. We present here several experimental results and a descriptive model of the phenomenon.

  17. [A negative first-line work-up of Raynaud's phenomenon: And what if it were cancer?].

    PubMed

    Auboire, L; Landy, S; Perrot, J-Y; Maïza, D; Le Hello, C

    2010-02-01

    Raynaud's phenomenon is a transient paroxysmal vasomotor phenomenon affecting the extremities including manifestations of ischemia. It is a common phenomenon in the general population. In a routine clinical situation, the first step is to differentiate Raynaud's disease from a secondary Raynaud's phenomenon, the latter requiring complementary investigations. We report here the case of an 80-year-old woman who presented a secondary Raynaud's phenomenon. First-line investigations remained negative. A mammography was performed and revealed breast cancer. Raynaud's phenomenon disappeared after treatment of the breast carcinoma and did not recur during the 2-year follow-up.

  18. Prevalence of Raynaud phenomenon and nailfold capillaroscopic abnormalities in Fabry disease: a cross-sectional study.

    PubMed

    Deshayes, Samuel; Auboire, Laurent; Jaussaud, Roland; Lidove, Olivier; Parienti, Jean-Jacques; Triclin, Nathalie; Imbert, Bernard; Bienvenu, Boris; Aouba, Achille

    2015-05-01

    Fabry disease (FD) is a lysosomal disorder leading to progressive systemic involvement, including microvascular damage that leads to neurological and cardiovascular disorders. We hypothesize that the latter could be documented at an early stage by performing a microcirculation study with nailfold capillaroscopy and evaluation of Raynaud phenomenon.The objective was to measure the prevalence of Raynaud phenomenon and nailfold capillaroscopic abnormalities in FD.This cross-sectional study included a standardized questionnaire and a nailfold capillaroscopy that assessed previously reported patterns in FD (dystrophic and giant capillaries, avascular fields, irregular architecture, dilatation and density of capillaries, hemorrhage), and was conducted on 32 Fabry patients and 39 controls. Capillaroscopic photographs were reviewed by 2 independent blinded investigators.Twelve Fabry patients (38%) suffered from Raynaud phenomenon, 5 were males (ie, 50% of male Fabry patients), compared with 2 controls (13%) (P < 0.001), of whom none were males (P < 0.001). Raynaud phenomenon was concomitant or before the occurrence of pain in the extremities in 42% of Fabry patients.More ramified capillaries were significantly observed in Fabry patients (12/32, 38%) than in controls (5/39, 13%, P = 0.016).Secondary Raynaud phenomenon should lead to screening for FD, especially in men. By extension, in high-risk populations for FD, the presence of Raynaud phenomenon and ramified capillaries should be assessed.

  19. Guillain–Barré syndrome presenting with Raynaud’s phenomenon: a case report

    PubMed Central

    2014-01-01

    Background Guillain–Barré syndrome is an immune mediated acute inflammatory polyradiculo-neuropathy involving the peripheral nervous system. Commonest presentation is acute or subacute flaccid ascending paralysis of limbs. Rarely autonomic dysfunction can be the presenting feature of Guillain–Barré syndrome. Raynaud’s phenomenon, although had been described in relation to many disease conditions, has not been described in association with Guillain–Barré syndrome up to date. Case presentation We report the first case of Guillain–Barré syndrome presenting with Raynaud’s phenomenon in a 21-year-old previously well boy. New onset Raynaud’s phenomenon was experienced followed by acute ascending flaccid paralysis of lower limbs and upper limbs together with palpitations and postural giddiness. Nerve conduction studies showed acute inflammatory demyelinating polyneuropathy with cerebrospinal fluid cyto-protein dissociation. He was treated with intravenous immunoglobulin and showed a satisfactory clinical recovery of muscle weakness, Raynaud’s phenomenon and autonomic disturbances. Conclusion Guillain–Barré syndrome presenting with Raynaud’s phenomenon is not being reported in literature previously. Although the underlying mechanism is not fully understood, Raynaud’s phenomenon should prompt the physician to consider Guillain–Barré syndrome with a complimentary clinical picture. PMID:25182165

  20. Scaling phenomena of isobaric yields in projectile fragmentation, spallation, and fission reactions

    NASA Astrophysics Data System (ADS)

    Ma, Chun-Wang; Huang, Ling; Song, Yi-Dan

    2017-02-01

    Background: The isobaric ratio difference scaling phenomenon, which has been found for the fragments produced in projectile fragmentation reactions, is related to the nuclear density change in reaction systems. Purpose: To verify whether the isobaric ratio difference scaling exists in the fragments produced in the spallation and fission reactions. Methods: The isobaric ratio difference scaling, denoted by SΔ lnR21 , is in theory deduced within the framework of the canonical ensemble theory at the grand-canonical limitation. The fragments measured in a series of projectile fragmentation, spallation, and fission reactions have been analyzed. Results: A good SΔ lnR21 scaling phenomenon is shown for the fragments produced both in the projectile fragmentation reactions and in the spallation reactions, whereas the SΔ lnR21 scaling phenomenon for the fragments in the fission reaction is less obvious. Conclusions: The SΔ lnR21 scaling is used to probe the properties of the equilibrium system at the time of fragment formation. The good scaling of SΔ lnR21 suggests that the equilibrium state can be achieved in the projectile fragmentation and spallation reactions. Whereas in the fission reaction, the result of SΔ lnR21 indicates that the equilibrium of the system is hard to achieve.

  1. Raynaud's Phenomenon

    MedlinePlus

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  2. Raynaud phenomenon

    MedlinePlus

    ... erythematosus ) Repeated injury or usage (such as from typing, playing the piano, or heavy use of hand ... ears, or nose become white, and then turn blue. When blood flow returns, the area becomes red and then ...

  3. Intercrystalline distal-effect on the afterglow phenomenon in photoluminescent SrAl2O4:Ce(III), Ln nanotube growth

    NASA Astrophysics Data System (ADS)

    Khaled Zurba, Nadia; Bdikin, Igor; Kholkin, Andrei; Golberg, Dmitri; Ferreira, José M. F.

    2010-08-01

    We report a new method for the synthesis of photoluminescent SrAl2O4:Ce3 + , Dy3 + , Eu2 + nanotubes, PL-SNT:Ce(III), Ln, using solid-state reaction and post-annealing approach. This new optical nanotubular structure was characterized by HRTEM, SEM, AFM, EDX, steady-state and time-resolved PL spectroscopy. A series of f-f and f-d-transitions with light emission in structured bands peaking at 488 nm arising from the polymorphism of the host lattice was correlated with an intercrystalline distal-effect on the afterglow phenomenon.

  4. Hypothesis: the influence of cavitation or vacuum phenomenon for decompression sickness.

    PubMed

    Yanagawa, Youichi; Omori, Kazuhiko; Ishikawa, Kouhei; Jitsuiki, Kei; Yoshizawa, Toshihiko; Takeuchi, Ikuto; Ohsaka, Hiromichi

    2016-09-01

    Attention has recently been focused on the vacuum phenomenon detected by computed tomography (CT), where gas in the human body is incidentally detected by CT. We introduce our hypothesis that the vacuum phenomenon increases the risk of decompression sickness (DCS) in subjects who engage in post-diving exercise. When the screw propeller of a ship operates underwater, a swirling effect called cavitation occurs. This swirling effect is closely related to the ship's propulsive efficiency as well as propeller cracking and damage. Hydrodynamic cavitation describes the process of vaporization, bubble generation, and bubble implosion that occurs in a flowing liquid as a result of a decrease and subsequent increase in local pressure. The formation of cavitation depends on the pressure, speed, temperature, viscosity, turbulence, or existence of impurities in the fluid; the evaporation of inert gas; and the form and surface roughness of the screw. These factors also resemble risk factors of DCS. In the human body, the cavitation effect has been recognized in radiological studies, where it is referred to as the 'vacuum phenomenon'. The mechanism responsible for the formation of the vacuum phenomenon has been described recently. If an enclosed tissue space is allowed to expand as a rebound phenomenon after an external impact, the volume within the enclosed space will increase. Under this condition of expanding volume, the pressure within the space will decrease. The solubility of the gas in the enclosed space will then subsequently decrease as the pressure inside the space decreases, allowing a gas such as nitrogen to leave solution. The combination of reduced nitrogen solubility and the minimal metabolism of nitrogen by the body mainly accounts for the formation of the vacuum phenomenon. The vacuum phenomenon has been observed in normal joints, degenerative intervertebral discs, the spine and spinal canal and traumatized tissues (Figure 1). Exercise induces the inflation and

  5. The Urban Heat Island Phenomenon: How Its Effects Can Influence Environmental Decision Making in Your Community

    NASA Technical Reports Server (NTRS)

    Estes, Maurice G., Jr.; Quattrochi, Dale; Stasiak, Elizabeth

    2003-01-01

    Reinvestment in urban centers is breathing new life into neighborhoods that have been languishing as a result of explosive suburban development over the past several decades. In cities all over the country, adaptive reuse, brownfields redevelopment, transforming urban landscapes, economies, and quality of life. However, the way in which this development occurs has the potential to exacerbate the urban heat island (UHI) phenomenon, an existing problem in many areas and one which poses a threat to the long-term sustainability and environmental quality of cities. The UHI phenomenon is rooted in the science of how the land covers respond to solar heating and can adversely effect the environment. This phenomenon is responsible for urban centers having higher air temperatures and poorer air quality than suburban areas. In addition, the UHI phenomenon causes metrological occurrences, degrades water quality, increases energy demands, poses threats to public health and contributes to global warming. While the name of the phenomenon implies that is solely an urban issue, research has shown that the effects of the UHI are becoming prevalent in suburbs, as well. The UHI phenomenon can plague regions - urban centers and their suburbs. Furthermore, heat islands have been found to exist in both city centers and suburban communities. As suburban areas increasingly develop using land covers and building materials common to urban areas, they are inheriting urban problems - such as heat islands. In this way, it may be necessary for non-urban communities to engage in heat island mitigation. The good news is that through education and planning, the effects of the UHI phenomenon can be prevented and mitigated. Heat islands are more a product of urban design rather than the density of development. Therefore, cities can continue to grow and develop without exacerbating the UHI by employing sustainable development strategies.

  6. A Nuclear Reaction Analysis study of fluorine uptake in flint

    SciTech Connect

    Jin, Jian-Yue; Weathers, D. L.; Picton, F.; Hughes, B. F.; Duggan, J. L.; McDaniel, F. D.; Matteson, S.

    1999-06-10

    Nuclear Reaction Analysis (NRA) using the {sup 19}F(p,{alpha}{gamma}){sup 16}O resonance reaction is a powerful method of fluorine depth profiling. We have used this method to study the fluorine uptake phenomenon in mineral flint, which could potentially develop into a method of dating archeological flint artifacts. Flint samples cut with a rock saw were immersed in aqueous fluoride solutions for different times for the uptake study. The results suggest that fluorine uptake is not a simple phenomenon, but rather a combination of several simultaneous processes. Fluorine surface adsorption appears to play an important role in developing the fluorine profiles. The surface adsorption was affected by several parameters such as pH value and fluorine concentration in the solution, among others. The problem of surface charging for the insulator materials during ion bombardment is also reported.

  7. Suicide Terrorism in America?: The Complex Social Conditions of This Phenomenon and the Implications for Homeland Security

    DTIC Science & Technology

    2014-11-05

    release; distribution is unlimited SUICIDE TERRORISM IN AMERICA?: THE COMPLEX SOCIAL CONDITIONS OF THIS PHENOMENON AND THE IMPLICATIONS FOR...SUBTITLE SUICIDE TERRORISM IN AMERICA?: THE COMPLEX SOCIAL CONDITIONS OF THIS PHENOMENON AND THE IMPLICATIONS FOR HOMELAND SECURITY 5. FUNDING...relations theory to the phenomenon of suicide terrorism and develops a framework that can be used to better understand the threat of suicide

  8. Meyerson phenomenon in children: observation in five cases of congenital melanocytic nevi.

    PubMed

    Rolland, Sébastien; Kokta, Victor; Marcoux, Danielle

    2009-01-01

    To describe the characteristics of five pediatric patients with the Meyerson phenomenon associated with congenital melanocytic nevi, five cases were reviewed to retrieve information relating to clinical presentation, treatment and evolution of the eczematous phenomenon and of the nevi. Three of five patients were male. Mean age at presentation of the Meyerson phenomenon was 23 months (range: 4 mos-4 yrs). Three patients presented with only one halo eczematous lesion, while two patients presented with more then one halo eczematous lesions. The halo eczematous lesions were located on the leg, arm, and trunk in four, two, and two patients, respectively. All were associated with congenital melanocytic nevi with overlying hypertrichosis. Four were treated with topical corticosteroids, and five developed some degree of hypopigmentation within the nevic lesion. In children with Meyerson phenomenon associated with congenital hairy melanocytic nevi, neither trigger to the eczematous eruption nor preferential gender or anatomical site location was identified. The Meyerson phenomenon evolved towards hypopigmentation of the congenital melanocytic nevic lesions in all patients but no other cutaneous changes were observed on follow-up.

  9. Disintegration of the 'waterfall phenomenon' in the inferior vena cava due to right heart failure.

    PubMed

    Kira, S; Dambara, T; Mieno, T; Tamaki, S; Natori, H

    1996-03-01

    The concept of the waterfall phenomenon in Zone 2 in the pulmonary vasculature is well known from West's lung model. It is believed that the flow through this zone is determined by the pressure difference between the pulmonary artery and alveoli, and the left atrial pressure is not transmissible to the alveolar capillaries. However, it is impossible to see whether alveolar capillaries are really displaying the waterfall phenomenon or not. In this review, the interrelation between the flow and geometry of the alveolar capillaries in the waterfall phenomenon is analyzed based on physiological studies using a model system and isolated lung lobe experiments. Further, extending the concept to the analysis of ventilatory changes of the inferior vena cava (IVC) configuration, it is ascertained that the waterfall phenomenon normally occurs in the IVC during inspiration just before it enters the thorax and the waterfall phenomenon in the IVC disintegrates with elevation of the central venous pressure. Because these configurations of the IVC in normal and abnormal conditions are visible with ultrasonography, the technique is very useful as a noninvasive approach to diagnose right heart failure.

  10. Fluctuation enhanced electrochemical reaction rates at the nanoscale

    PubMed Central

    García-Morales, Vladimir; Krischer, Katharina

    2010-01-01

    The electrode potential constitutes a dynamical variable whenever an electrode is resistively coupled to the electric circuit. We show that at the nanoscale, the discreteness and stochasticity of an electron transfer event causes fluctuations of the electrode potential that render all elementary electrochemical reactions to be faster on a nanoelectrode than predicted by the macroscopic (Butler–Volmer) electrochemical kinetics. This phenomenon is substantiated by means of a generalized (electro)chemical master equation. PMID:20176966

  11. Successive splitting of autowaves in a nonlinear chemical reaction medium.

    PubMed

    Okano, Taiji; Matsuda, Yuki; Miyakawa, Kenji

    2006-12-01

    The phenomenon of wave splitting is investigated in a two-dimensional excitable light-sensitive Belousov-Zhabotinsky reaction medium after extremely changing the intensity of illuminated light for a short time. It is found that successive wave splitting and nonannihilation collision between two waves of different amplitudes occur spontaneously under narrow experimental conditions. Experimental observations are approximately reproduced in the specific parameter range by a numerical simulation with a Bär-Eiswirth model.

  12. Influence of neighboring reactive particles on diffusion-limited reactions

    PubMed Central

    Eun, Changsun; Kekenes-Huskey, Peter M.; McCammon, J. Andrew

    2013-01-01

    Competition between reactive species is commonplace in typical chemical reactions. Specifically the primary reaction between a substrate and its target enzyme may be altered when interactions with secondary species in the system are substantial. We explore this competition phenomenon for diffusion-limited reactions in the presence of neighboring particles through numerical solution of the diffusion equation. As a general model for globular proteins and small molecules, we consider spherical representations of the reactants and neighboring particles; these neighbors vary in local density, size, distribution, and relative distance from the primary target reaction, as well as their surface reactivity. Modulations of these model variables permit inquiry into the influence of excluded volume and competition on the primary reaction due to the presence of neighboring particles. We find that the surface reactivity effect is long-ranged and a strong determinant of reaction kinetics, whereas the excluded volume effect is relatively short-ranged and less influential in comparison. As a consequence, the effect of the excluded volume is only modestly dependent on the neighbor distribution and is approximately additive; this additivity permits a linear approximation to the many-body effect on the reaction kinetics. In contrast, the surface reactivity effect is non-additive, and thus it may require higher-order approximations to describe the reaction kinetics. Our model study has broad implications in the general understanding of competition and local crowding on diffusion-limited chemical reactions. PMID:23901970

  13. Noncanonical reactions of flavoenzymes.

    PubMed

    Sobrado, Pablo

    2012-11-05

    Enzymes containing flavin cofactors are predominantly involved in redox reactions in numerous cellular processes where the protein environment modulates the chemical reactivity of the flavin to either transfer one or two electrons. Some flavoenzymes catalyze reactions with no net redox change. In these reactions, the protein environment modulates the reactivity of the flavin to perform novel chemistries. Recent mechanistic and structural data supporting novel flavin functionalities in reactions catalyzed by chorismate synthase, type II isopentenyl diphosphate isomerase, UDP-galactopyranose mutase, and alkyl-dihydroxyacetonephosphate synthase are presented in this review. In these enzymes, the flavin plays either a direct role in acid/base reactions or as a nucleophile or electrophile. In addition, the flavin cofactor is proposed to function as a "molecular scaffold" in the formation of UDP-galactofuranose and alkyl-dihydroxyacetonephosphate by forming a covalent adduct with reaction intermediates.

  14. Reaction spreading on graphs.

    PubMed

    Burioni, Raffaella; Chibbaro, Sergio; Vergni, Davide; Vulpiani, Angelo

    2012-11-01

    We study reaction-diffusion processes on graphs through an extension of the standard reaction-diffusion equation starting from first principles. We focus on reaction spreading, i.e., on the time evolution of the reaction product M(t). At variance with pure diffusive processes, characterized by the spectral dimension d{s}, the important quantity for reaction spreading is found to be the connectivity dimension d{l}. Numerical data, in agreement with analytical estimates based on the features of n independent random walkers on the graph, show that M(t)∼t{d{l}}. In the case of Erdös-Renyi random graphs, the reaction product is characterized by an exponential growth M(t)e{αt} with α proportional to ln(k), where (k) is the average degree of the graph.

  15. Photoneutron Reactions in Nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Utsunomiya, Hiroaki

    Photoneutron reactions are discussed in the context of nucleosynthesis with emphasis on a unified understanding of (γ, n) and (n, γ) reactions for heavy nuclei through the γ-ray strength function and a revisit to explosive nucleosynthesis of 9Be through the reciprocity theorem. The role of photonuclear reactions in nucleosynthesis is supplemented by the photonuclear data project (IAEA-CRP F42032) and will be strengthened in the Extreme Light Infrastructure-Nuclear Physics (ELI-NP) in the future.

  16. Nuclear reaction studies

    SciTech Connect

    Alexander, J.M.; Lacey, R.A.

    1994-11-01

    Research focused on the statistical and dynamical properties of ``hot`` nuclei formed in symmetric heavy-ion reactions. Theses included ``flow`` measurements and the mechanism for multifragment disassembly. Model calculations are being performed for the reactions C+C, Ne+Al, Ar+Sc, Kr+Nb, and Xe+La. It is planned to study {sup 40}Ar reactions from 27 to 115 MeV/nucleon. 2 figs., 41 refs.

  17. Sleeve reaction chamber system

    DOEpatents

    Northrup, M. Allen; Beeman, Barton V.; Benett, William J.; Hadley, Dean R.; Landre, Phoebe; Lehew, Stacy L.; Krulevitch, Peter A.

    2009-08-25

    A chemical reaction chamber system that combines devices such as doped polysilicon for heating, bulk silicon for convective cooling, and thermoelectric (TE) coolers to augment the heating and cooling rates of the reaction chamber or chambers. In addition the system includes non-silicon-based reaction chambers such as any high thermal conductivity material used in combination with a thermoelectric cooling mechanism (i.e., Peltier device). The heat contained in the thermally conductive part of the system can be used/reused to heat the device, thereby conserving energy and expediting the heating/cooling rates. The system combines a micromachined silicon reaction chamber, for example, with an additional module/device for augmented heating/cooling using the Peltier effect. This additional module is particularly useful in extreme environments (very hot or extremely cold) where augmented heating/cooling would be useful to speed up the thermal cycling rates. The chemical reaction chamber system has various applications for synthesis or processing of organic, inorganic, or biochemical reactions, including the polymerase chain reaction (PCR) and/or other DNA reactions, such as the ligase chain reaction.

  18. Raynaud's phenomenon: new aspects of pathogenesis and the role of nailfold videocapillaroscopy.

    PubMed

    Kuryliszyn-Moskal, Anna; Kita, Jacek; Hryniewicz, Anna

    2015-01-01

    Raynaud's phenomenon (RP) refers to paroxysmal pallor or cyanosis of the digits of the hands or feet and, infrequently, the tips of the nose or ears (acral parts) owing to cold-induced vasoconstriction of the digital arteries, precapillary arterioles, and cutaneous arteriovenous shunts. Raynaud's phenomenon reflects an exaggeration of normal central and local vasomotor responses to cold or emotion. Raynaud's phenomenon has been classified as primary or secondary, depending on whether it occurs as an isolated condition or is associated mainly with a connective tissue disease. Dysregulation of autonomic and sensitive nerve fibers, functional and structural vessel changes, and intravascular alterations can be observed in the pathogenesis of RP. Nailfold videocapillaroscopy (NVC) is the best non-invasive and repetitive diagnostic technique for detecting morpho-functional changes in the microcirculation. Nailfold videocapillaroscopy is accepted in early diagnosis and monitoring of primary and secondary RP.

  19. Fluctuating Hemiparesis Secondary to Moyamoya Phenomenon in a Child with Down Syndrome: a case report.

    PubMed

    Rison, Richard A

    2008-10-15

    Moyamoya phenomenon is a term used to describe extensive collateralization of the circle of Willis arteries associated with severe unilateral or bilateral internal carotid artery stenosis or occlusion in the presence of certain conditions. Down syndrome is among these conditions. A case is reported of a young girl with Down syndrome who presented with fluctuating right-sided weakness and facial droop found to have cerebral ischemia. Subsequent investigations disclosed characteristic "puff of smoke" patterns on angiographic studies consistent with moyamoya phenomenon. The patient was initially treated with aspirin and eventually underwent an encephalomyosynangiosis. This young patient with Down syndrome and moyamoya phenomenon serves as a reminder of the association between these two conditions.

  20. B[e] Phenomenon in the D-type Symbiotic Star V1016 Cyg

    NASA Astrophysics Data System (ADS)

    Sekeráš, M.; Skopal, A.

    2017-02-01

    V1016 Cygni is a symbiotic binary consisting of a Mira-type variable and a hot and luminous white dwarf (WD). Its spectrum shows distinctive features of the B[e] phenomenon. The spectral energy distribution reveals two dusty envelopes, probably surrounding the Mira, with different temperature and heated by the radiation from both binary components. Signatures of the B[e] phenomenon in the optical region are represented by strong Balmer emission lines, low excitation permitted emission lines of metals, and forbidden emission lines. In addition to the typical B[e] phenomenon features, numerous emission lines of highly ionized elements, such as He II, O V, [Fe VII], and [Ar V], are also present. Most of the forbidden lines have double-peaked profile, suggesting a bipolar structure of the low density emitting region in the binary.

  1. Scrotal Apocrine Adenocarcinoma with Pagetoid Phenomenon and Inguinal Lymph Node Metastases

    PubMed Central

    Fyllos, Apostolos Haralampos; Havaki, Sophia; Sotiriou, Sotirios; Kotakidis, Georgios; Arvanitis, Dimitrios Leonidas

    2016-01-01

    We report a case of scrotal apocrine adenocarcinoma in a 72-year-old Caucasian male which was initially presented as a reddish superficial lesion which in time became an ulcerated nodule. The initial pathological examination showed an apocrine adenocarcinoma with pagetoid phenomenon. The tumor recurred after four months and then excision biopsy showed tumor with pagetoid phenomenon which reached all the surgical margins. Three months later an ulcerated nodule in the scrotum and greatly enlarged ipsilateral inguinal lymph nodes were noticed. The final pathological examination showed multiple separated malignant foci, some with overlying pagetoid phenomenon and inguinal lymph node metastases. Immunohistochemistry showed positivity for Gross Cystic Disease Fluid Protein-15 (GCDFP-15), androgen receptors, and score 3+ for the Human Epidermal growth factor Receptor-2 (HER2). The aggressive behavior of the present tumor goes along with previous reports showing that HER2 high score cases exhibit a worse prognosis. PMID:27818816

  2. The "boom and bust phenomenon": the hopes, dreams, and broken promises of the contraceptive revolution.

    PubMed

    Boonstra, H; Duran, V; Northington Gamble, V; Blumenthal, P; Dominguez, L; Pies, C

    2000-01-01

    The "boom and bust phenomenon" is a pattern that has emerged in the development, introduction, and delivery of a number of significant new contraceptive products in the United States. When a new contraceptive product is introduced with great promise and publicity, it usually experiences a "boom" during which sales, demand, and expectations are high. This boom is often followed by a "bust" phase during which a product does not live up to expectations, initial excitement falls off, and a drop in sales and use ensues. The boom and bust phenomenon goes to the heart of what some have referred to as the failed promise of the contraception revolution by creating obstacles to significant expansion of contraceptive choice in the United States. Case studies of oral contraceptives, intrauterine devices, and Norplant(R) are used to illustrate the boom and bust phenomenon and the effect it has had in shaping the direction of advances in contraceptive technology.

  3. Raynaud's phenomenon: new aspects of pathogenesis and the role of nailfold videocapillaroscopy

    PubMed Central

    Kuryliszyn-Moskal, Anna; Hryniewicz, Anna

    2015-01-01

    Raynaud's phenomenon (RP) refers to paroxysmal pallor or cyanosis of the digits of the hands or feet and, infrequently, the tips of the nose or ears (acral parts) owing to cold-induced vasoconstriction of the digital arteries, precapillary arterioles, and cutaneous arteriovenous shunts. Raynaud's phenomenon reflects an exaggeration of normal central and local vasomotor responses to cold or emotion. Raynaud's phenomenon has been classified as primary or secondary, depending on whether it occurs as an isolated condition or is associated mainly with a connective tissue disease. Dysregulation of autonomic and sensitive nerve fibers, functional and structural vessel changes, and intravascular alterations can be observed in the pathogenesis of RP. Nailfold videocapillaroscopy (NVC) is the best non-invasive and repetitive diagnostic technique for detecting morpho-functional changes in the microcirculation. Nailfold videocapillaroscopy is accepted in early diagnosis and monitoring of primary and secondary RP. PMID:27407233

  4. Induced Bacterial Cross-Resistance toward Host Antimicrobial Peptides: A Worrying Phenomenon

    PubMed Central

    Fleitas, Osmel; Franco, Octávio L.

    2016-01-01

    Bacterial resistance to conventional antibiotics has reached alarming levels, threatening to return to the pre-antibiotic era. Therefore, the search for new antimicrobial compounds that overcome the resistance phenomenon has become a priority. Antimicrobial peptides (AMPs) appear as one of the most promising antibiotic medicines. However, in recent years several AMP-resistance mechanisms have been described. Moreover, the AMP-resistance phenomenon has become more complex due to its association with cross-resistance toward AMP effectors of the host innate immune system. In this context, the use of AMPs as a therapeutic option could be potentially hazardous, since bacteria could develop resistance toward our innate immune system. Here, we review the findings of major studies that deal with the AMP cross-resistance phenomenon. PMID:27047486

  5. Wave of mutilation: the cattle mutilation phenomenon of the 1970s.

    PubMed

    Goleman, Michael J

    2011-01-01

    During the 1970s many small-scale cattle ranchers across the Midwest reported finding their cattle mutilated. The episode, often dismissed as mass hysteria or sensationalized reporting, demonstrates the growing dissatisfaction of many ranchers concerning government intrusiveness and restrictive policies. These frustrations found a release in response to the mutilation phenomenon during which ranchers vented their anger by taking direct aim at the federal government. The turbulent economic conditions of the period paired with government interference in the cattle industry helped sustain the mutilation phenomenon as ranchers projected their fears and insecurities through the bizarre episode. The hostility ranchers showed toward the federal government during the mutilation scare presaged and helped provide the impetus for events such as the Sagebrush Rebellion. The mutilation phenomenon also underscores the pronounced effects of the libertarian movement of the 1960s that gave rise to the New Right and gained adherents across the West and Midwest.

  6. Myeloproliferative Disease: An Unusual Cause of Raynaud's Phenomenon and Digital Ischaemia

    PubMed Central

    Huws, Gwenan; Lawson, Tom

    2016-01-01

    We describe a 59-year-old female who presented with ischaemic digits, preceded by a 6-month history of Raynaud's phenomenon affecting her fingers and toes. There were no clinical or laboratory features of primary vasculitis or connective tissue disease, Doppler imaging was normal, and bloods were unremarkable aside from a platelet count of 786 × 109/L (150–400) and white cells of 16 × 109/L (4–11). In view of the thrombocytosis a JAK2 mutation assay was requested which confirmed a JAK2 V617F mutation, suggesting essential thrombocytosis (ET) as the cause. She received treatment with hydroxycarbamide which normalised her platelet count and led to a complete resolution of her Raynaud's symptoms. Raynaud's phenomenon is a rare manifestation of ET. Myeloproliferative disorders such as ET should be considered in the differential diagnosis of Raynaud's phenomenon and vasculitis. PMID:27895669

  7. Spin-Flop Phenomenon of Two-Dimensional Frustrated Antiferromagnets without Anisotropy in Spin Space

    NASA Astrophysics Data System (ADS)

    Nakano, Hiroki; Sakai, Tôru; Hasegawa, Yasumasa

    2014-08-01

    Motivated by a recent finding of a spin-flop phenomenon in a system without anisotropy in spin space reported in the S = 1/2 Heisenberg antiferromagnet on the square-kagome lattice, we study the S = 1/2 Heisenberg antiferromagnets on two other lattices composed of vertex-sharing triangles by the numerical diagonalization method. One is a novel lattice including a shuriken shape with four teeth; the other is the kagome lattice with √{3} × √{3} -structure distortion, which includes a shuriken shape with six teeth. We find in the magnetization processes of these systems that a magnetization jump accompanied by a spin-flop phenomenon occurs at the higher-field-side edge of the magnetization plateau at one-third the height of saturation. This finding indicates that the spin-flop phenomenon found in the isotropic system on the square-kagome lattice is not an exceptional case.

  8. Myeloproliferative Disease: An Unusual Cause of Raynaud's Phenomenon and Digital Ischaemia.

    PubMed

    Beynon, Celia; Huws, Gwenan; Lawson, Tom

    2016-01-01

    We describe a 59-year-old female who presented with ischaemic digits, preceded by a 6-month history of Raynaud's phenomenon affecting her fingers and toes. There were no clinical or laboratory features of primary vasculitis or connective tissue disease, Doppler imaging was normal, and bloods were unremarkable aside from a platelet count of 786 × 109/L (150-400) and white cells of 16 × 109/L (4-11). In view of the thrombocytosis a JAK2 mutation assay was requested which confirmed a JAK2 V617F mutation, suggesting essential thrombocytosis (ET) as the cause. She received treatment with hydroxycarbamide which normalised her platelet count and led to a complete resolution of her Raynaud's symptoms. Raynaud's phenomenon is a rare manifestation of ET. Myeloproliferative disorders such as ET should be considered in the differential diagnosis of Raynaud's phenomenon and vasculitis.

  9. Induced Bacterial Cross-Resistance toward Host Antimicrobial Peptides: A Worrying Phenomenon.

    PubMed

    Fleitas, Osmel; Franco, Octávio L

    2016-01-01

    Bacterial resistance to conventional antibiotics has reached alarming levels, threatening to return to the pre-antibiotic era. Therefore, the search for new antimicrobial compounds that overcome the resistance phenomenon has become a priority. Antimicrobial peptides (AMPs) appear as one of the most promising antibiotic medicines. However, in recent years several AMP-resistance mechanisms have been described. Moreover, the AMP-resistance phenomenon has become more complex due to its association with cross-resistance toward AMP effectors of the host innate immune system. In this context, the use of AMPs as a therapeutic option could be potentially hazardous, since bacteria could develop resistance toward our innate immune system. Here, we review the findings of major studies that deal with the AMP cross-resistance phenomenon.

  10. Bimodality: a sign of critical behavior in nuclear reactions.

    PubMed

    Le Fèvre, A; Aichelin, J

    2008-02-01

    The recently discovered coexistence of multifragmentation and residue production for the same total transverse energy of light charged particles, which has been dubbed bimodality like it has been introduced in the framework of equilibrium thermodynamics, can be well reproduced in numerical simulations of heavy ion reactions. A detailed analysis shows that fluctuations (introduced by elementary nucleon-nucleon collisions) determine which of the exit states is realized. Thus, we can identify bifurcation in heavy ion reactions as a critical phenomenon. Also the scaling of the coexistence region with beam energy is well reproduced in these results from the quantum molecular dynamics simulation program.

  11. Loss of chromosome Y in acute lymphoblastic leukemia: age related or neoplastic phenomenon?

    PubMed

    Gupta, Anurag; Parihar, Mayur; Remani, Arun S; Mishra, Deepak Kumar

    2014-01-01

    Loss of chromosome Y (LOY) in the bone marrow has long been considered as an age-related phenomenon with an incidence of more than 25% in males beyond the age of 80 years. Though reported as an acquired abnormality in myeloid neoplasms, it has rarely been described in B-lymphoblastic leukemia which primarily is a disease of the young. We describe here in three cases of pediatric B-lymphoblastic leukemia with LOY. Conventional cytogenetic studies and fluorescence in situ hybridization studies using centromeric probes for chromosome X and Y on peripheral blood samples ruled out constitutional LOY in all the three cases favoring it to be a neoplastic phenomenon.

  12. On the validity and robustness of the scale error phenomenon in early childhood.

    PubMed

    DeLoache, Judy S; LoBue, Vanessa; Vanderborght, Mieke; Chiong, Cynthia

    2013-02-01

    Scale errors is a term referring to very young children's serious efforts to perform actions on miniature replica objects that are impossible due to great differences in the size of the child's body and the size of the target objects. We report three studies providing further documentation of scale errors and investigating the validity and robustness of the phenomenon. In the first, we establish that 2-year-olds' behavior in response to prompts to "pretend" with miniature replica objects differs dramatically from scale errors. The second and third studies address the robustness of the phenomenon and its relative imperviousness to attempts to influence the rate of scale errors.

  13. The use of an exoskeleton to investigate the self advantage phenomenon.

    PubMed

    Moreau, R; Moubarak, S; Pham, M T; Frassinetti, F; Farne, A

    2013-01-01

    This paper presents an upper extremity exoskeleton with an original application in neuroscience. The novelty of this study is the investigation of the self-advantage phenomenon under various experimental conditions. Usually this kind of experiments lies only on human visual ability to explicitly and/or implicitly recognize their own arm movements. Using an exoskeleton to replay recorded trajectories allows to give another perspective to the previous studies in including the proprioceptive ability of humans. Twelve healthy subjects were involved in this study. The results show that the self advantage phenomenon is even more present in the implicit tasks.

  14. The suppression effect of external magnetic field on the high-power microwave window multipactor phenomenon

    SciTech Connect

    Zhang, Xue Wang, Yong; Fan, Junjie

    2015-02-15

    To suppress the surface multipactor phenomenon and improve the transmitting power of the high-power microwave window, the application of external magnetic fields is theoretically analyzed and simulated. A Monte Carlo algorithm is used to track the secondary electron trajectories and study the multipactor scenario on the surface of a cylinder window. It is confirmed that over-resonant magnetic fields (an external magnetic field whose magnitude is slightly greater than that of a resonant magnetic field) will generate a compensating trajectory and collision, which can suppress the secondary electron avalanche. The optimal value of this external magnetic field that will avoid the multipactor phenomenon on cylinder windows is discussed.

  15. Exhibition of circular Bragg phenomenon by hyperbolic, dielectric, structurally chiral materials

    NASA Astrophysics Data System (ADS)

    Lakhtakia, Akhlesh

    2014-01-01

    The relative permittivity dyadic of a dielectric structurally chiral material (SCM) varies helicoidally along a fixed direction; in consequence, the SCM exhibits the circular Bragg phenomenon, which is the circular-polarization-selective reflection of light. The introduction of hyperbolicity in an SCM-by making either one or two but not all three eigenvalues of the relative permittivity dyadic acquire negative real parts-does not eliminate the circular Bragg phenomenon, but significantly alters the regime for its exhibition. Significantly wider circular-polarization-sensitive stopbands may be exhibited by hyperbolic SCMs in comparison to nonhyperbolic SCMs. Physical vapor deposition techniques appear to be suitable to fabricate hyperbolic SCMs.

  16. Uhthoff`s phenomenon 125 years later - what do we know today?

    PubMed Central

    Opara, JA; Brola, W; Wylegala, AA; Wylegala, E

    2016-01-01

    125 years have passed since Wilhelm Uhthoff reported the symptoms he observed after an increased body temperature from physical exertion. Those symptoms, which might have led to the transient impairment of vision in patients with Multiple Sclerosis and also observed in optic neuritis, were later named after him "Uhthoff's phenomenon". This has defined the strategy of rehabilitation procedures in Multiple Sclerosis for more than 100 years, restricting the use of thermal treatments and the possibility of aerobic exercises. The current state of knowledge concerning the Uhthoff's phenomenon and its influence on comprehensive rehabilitation in Multiple Sclerosis were presented in the current review report. PMID:27974923

  17. Oscillating Reactions: Two Analogies

    ERIC Educational Resources Information Center

    Petruševski, Vladimir M.; Stojanovska, Marina I.; Šoptrajanov, Bojan T.

    2007-01-01

    Oscillating chemical reactions are truly spectacular phenomena, and demonstrations are always appreciated by the class. However, explaining such reactions to high school or first-year university students is problematic, because it may seem that no acceptable explanation is possible unless the students have profound knowledge of both physical…

  18. Degradations and Rearrangement Reactions

    NASA Astrophysics Data System (ADS)

    Zhang, Jianbo

    This section deals with recent reports concerning degradation and rearrangement reactions of free sugars as well as some glycosides. The transformations are classified in chemical and enzymatic ways. In addition, the Maillard reaction will be discussed as an example of degradation and rearrangement transformation and its application in current research in the fields of chemistry and biology.

  19. Photoinduced Multicomponent Reactions.

    PubMed

    Garbarino, Silvia; Ravelli, Davide; Protti, Stefano; Basso, Andrea

    2016-12-12

    The combination of multicomponent approaches with light-driven processes opens up new scenarios in the area of synthetic organic chemistry, where the need for sustainable, atom- and energy-efficient reactions is increasingly urgent. Photoinduced multicomponent reactions are still in their infancy, but significant developments in this area are expected in the near future.

  20. Lithium Cell Reactions.

    DTIC Science & Technology

    1983-12-01

    SUPPLEMENTARY NOTES It. KEY WORDS (Continue on reverse .,ide if necessary and Identify by block number) Batteries Thionyl Chloride Batteries Lithium ...Batteries Lithium Cells Primary Batteries Thionyl Chloride Cells Non Rechargeable Batteries Electrochemical Reactions 20. ABSTRACT (Continue on reverse...INVESTIGATION OF CHEMICAL, ELECTROCHEMICAL AND PARASITIC REACTIONS IN LITHIUM - THIONYL CHLORIDE CELLS .......................................... 1 1.0 IN TRO D UC

  1. Clock Reaction: Outreach Attraction

    ERIC Educational Resources Information Center

    Carpenter, Yuen-ying; Phillips, Heather A.; Jakubinek, Michael B.

    2010-01-01

    Chemistry students are often introduced to the concept of reaction rates through demonstrations or laboratory activities involving the well-known iodine clock reaction. For example, a laboratory experiment involving thiosulfate as an iodine scavenger is part of the first-year general chemistry laboratory curriculum at Dalhousie University. With…

  2. Hydrogen evolution reaction catalyst

    DOEpatents

    Subbaraman, Ram; Stamenkovic, Vojislav; Markovic, Nenad; Tripkovic, Dusan

    2016-02-09

    Systems and methods for a hydrogen evolution reaction catalyst are provided. Electrode material includes a plurality of clusters. The electrode exhibits bifunctionality with respect to the hydrogen evolution reaction. The electrode with clusters exhibits improved performance with respect to the intrinsic material of the electrode absent the clusters.

  3. REUSABLE REACTION VESSEL

    DOEpatents

    Soine, T.S.

    1963-02-26

    This patent shows a reusable reaction vessel for such high temperature reactions as the reduction of actinide metal chlorides by calcium metal. The vessel consists of an outer metal shell, an inner container of refractory material such as sintered magnesia, and between these, a bed of loose refractory material impregnated with thermally conductive inorganic salts. (AEC)

  4. Reactions to Attitudinal Deviancy.

    ERIC Educational Resources Information Center

    Levine, John M.; Allen, Vernon L.

    This paper presents a critical review of empirical and theoretical treatments of group reaction to attitudinal deviancy. Inspired by Festinger's (1950) ideas on resolution of attitudinal discrepancies in groups, Schachter (1951) conducted an experiment that has greatly influenced subsequent research and theory concerning reaction to attitudinal…

  5. Applications of Reaction Rate

    ERIC Educational Resources Information Center

    Cunningham, Kevin

    2007-01-01

    This article presents an assignment in which students are to research and report on a chemical reaction whose increased or decreased rate is of practical importance. Specifically, students are asked to represent the reaction they have chosen with an acceptable chemical equation, identify a factor that influences its rate and explain how and why it…

  6. Chemical Reaction Problem Solving.

    ERIC Educational Resources Information Center

    Veal, William

    1999-01-01

    Discusses the role of chemical-equation problem solving in helping students predict reaction products. Methods for helping students learn this process must be taught to students and future teachers by using pedagogical skills within the content of chemistry. Emphasizes that solving chemical reactions should involve creative cognition where…

  7. An Experimental Study of the Liesegang Phenomenon and Crystal Growth in Silica Gels.

    ERIC Educational Resources Information Center

    Sharbaugh, Amandus H., III; Sharbaugh, Amandus H., Jr.

    1989-01-01

    Reports on a 30-year-old longitudinal study of reactions in gels. Described are reactions and crystal growth in silica gels and diffusion studies of the Liesegang ring formation. Color photographs showing the reactions and graphs upon the diffusions are presented. (YP)

  8. Reactions and their management.

    PubMed

    Ganapati, R; Pai, V V

    2004-12-01

    The uneventful response to chemotherapy in leprosy is marked by clinically disturbing episodes encountered in 20-30% of patients and these phenomena are called "reactions". Generally they are classified as reversal reaction (type-1) and erythema nodosum leprosum (type-2). The cutaneous menifestations are: (1) Type-2 reactions in LL, BL types constituting erythema nodosum leprosum, erythema multiforme, erythema necroticans, subcutaneous nodules, lepromatous exacerbation. (2) Type-1 reactions in borderline and tuberculoid leprosy. The other manifestations include: Acute neuritis, lymphadenitis, arthritis, oedema of the hands and feet, ocular lesions, etc. Sequelae of reactions are: Paralytic deformities, non-paralytic deformities, extensive scarring and renal damage. A simple guideline to identify the risk-prone cases has been narrated. Prednisolone in standard dosage schedule as recommended by WHO is now being widely used in control programmes.

  9. The Problem of Moral Motivation and the Happy Victimizer Phenomenon: Killing Two Birds with One Stone

    ERIC Educational Resources Information Center

    Minnameier, Gerhard

    2010-01-01

    One surprising feature of cognitive and emotional development in the moral domain is the so-called happy victimizer phenomenon, which is commonly explained by a lack of moral motivation. Concerning this general approach, there are two pieces of news in this chapter. The bad news is that moral motivation is a highly problematic concept and its…

  10. Appropriate Educational Means of Dealing with the Phenomenon of Smoking among Zarqa University Students

    ERIC Educational Resources Information Center

    hatamleh, habes Moh'd; al Khaza'leh, Mohammed Salman

    2016-01-01

    The study aimed to identify the (appropriate educational means of dealing with the phenomenon of smoking among Zarqa University students), and to achieve this goal, the descriptive approach has been used, also used a questionnaire submitted to (800) students of the sample, and a couple of open questions has been submitted to 70 members of the…

  11. Approach to the Phenomenon of M-Learning in English Teaching

    ERIC Educational Resources Information Center

    García, Sergio; Fombona, Javier

    2015-01-01

    This research analyzes the situation of mobile devices and some specific options of support for the teaching of the English language. The features of this complex and novel phenomenon of Mobile-Assisted Language Learning (MALL) are addressed with an exploratory descriptive methodology. The article is part of a more extensive research which deals…

  12. The "Tsumari" Phenomenon in Performance of Beat Division: Tendencies and Possible Causes.

    ERIC Educational Resources Information Center

    Mito, Hiromichi

    1997-01-01

    Explores whether the tsumari phenomenon appears in the performance of keyboard instruments and maintains that tsumari will be severe among subjects with little music training. Finds that tsumari was seen most conspicuously in this beginner group. Concludes that the structural arrangement of the music plays an important role in the tsumari…

  13. Astronaut Maurizio Cheli, mission specialist, works with the Tether Optical Phenomenon System (TOPS)

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Astronaut Maurizio Cheli, mission specialist, works with the Tether Optical Phenomenon System (TOPS) on the flight deck of the Earth-orbiting Space Shuttle Columbia. Cheli, representing the European Space Agency (ESA), joined four other astronauts and an international payload specialists for 16 days of scientific research in Earth-orbit.

  14. Investigations into the Power MOSFET SEGR Phenomenon and its Physical Mechanism

    NASA Technical Reports Server (NTRS)

    Swift, G. M.; Edmonds, L. E.; Miyahira, T.; Nichols, D. K.; Johnston, A. H.

    1997-01-01

    The state of understanding of the destructive SEGR event in power MOSFETs is relatively mature with large published efforts, both experimental and theoretical. However, gasps remain in the uderstanding of the phenomenon, including unexplained anomalies, emperical-only dependencies on some important device and incident ion physical parameters, and limited insight into latent effets.

  15. Effect of Handling, Storage and Cycling on Ni-H2 Cells: Second Plateau Phenomenon

    NASA Technical Reports Server (NTRS)

    Vaidyanathan, Hari; Rao, Gopalakrishna M.; Day, John H. (Technical Monitor)

    2000-01-01

    A viewgraph presentation outlines the effects of handling, storing, and cycling of NiH2 cells, particularly the second plateau phenomenon. Details are given on the criteria for cell selection, cell history, the second plateau capacity at C/2 discharge, and cell reversal test conditions. Tables display a gas analysis and nickel precharge.

  16. Doctoral Students and the Impostor Phenomenon: Am I Smart Enough to Be Here?

    ERIC Educational Resources Information Center

    Craddock, Sarah; Birnbaum, Matt; Rodriguez, Katrina; Cobb, Christopher; Zeeh, Steven

    2011-01-01

    This study explores feelings associated with the impostor phenomenon (IP) as experienced by six doctoral students in a higher education program. Using data gathered from semi-structured interviews and a focus group, our analysis revealed that participants had feelings related to perceptions of inadequacy and academic preparedness. The authors…

  17. Two Causes of Underachievement--The Scapegoat Phenomenon and the Peter Pan Syndrome. Part II.

    ERIC Educational Resources Information Center

    Grau, Phyllis Nelson

    1986-01-01

    Two profiles of underachievement are described: the Peter Pan Syndrome, characterized by irresponsibility, anxiety, loneliness, sex role conflict, and narcissism, and the scapegoating phenomenon, in which children acquire negative self-images from victimization experiences. Prognoses and recommendations for each are offered. (Author/CL)

  18. Frequency and Severity of the Dawn Phenomenon in Type 2 Diabetes

    PubMed Central

    Monnier, Louis; Colette, Claude; Sardinoux, Mathieu; Baptista, Gregory; Regnier-Zerbib, Alyne; Owens, David

    2012-01-01

    OBJECTIVE To know whether age has an independent effect on the dawn phenomenon in noninsulin-using type 2 diabetes. RESEARCH DESIGN AND METHODS Eighty-one individuals with type 2 diabetes were matched for HbA1c and divided by age into three subgroups of 27 individuals (1: ≥70 years; 2: 60–69 years; and 3: ≤59 years). All underwent ambulatory continuous glucose monitoring for quantifying the dawn phenomenon (i.e., the absolute [∂G, mg/dL] or relative [∂G%] increments from nocturnal nadirs to prebreakfast time points). RESULTS HbA1c levels and 24-h glycemic profiles were similar across the three groups. Glucose increments (mean ± SEM) were identical in the three groups: ∂G (mg/dL), 22.0 ± 4.7 (1), 21.3 ± 3.6 (2), and 18.0 ± 3.6 (3) and δG (%), 19.9 ± 4.9 (1), 21.6 ± 4.4 (2), and 17.6 ± 4.2 (3). Using the most common definition (∂G >10 mg/dL), the prevalence of the dawn phenomenon was 52, 70, and 59% in groups 1, 2, and 3, respectively. CONCLUSIONS The dawn phenomenon is present in the elderly. PMID:22991448

  19. Learners' Level of Understanding of the Inclusion Relations of Quadrilaterals and prototype Phenomenon

    ERIC Educational Resources Information Center

    Fujita, Taro

    2012-01-01

    This paper reports on data from investigations on learners' understanding of inclusion relations of quadrilaterals, building on the ideas from our earlier study (Fujita & Jones, 2007). By synthesising past and current theories in the teaching of geometry (van Hiele's model, figural concepts, prototype phenomenon, etc.), we propose a theoretical…

  20. Mothers' Experiences Raising Children Who Have Multiple Disabilities and Their Perceptions of the Chronic Sorrow Phenomenon

    ERIC Educational Resources Information Center

    Parrish, Rosalie N.

    2010-01-01

    This qualitative study proposed to answer the following two questions: Do mothers of children who have multiple disabilities experience feelings that are consistent with chronic sorrow?, and What are mothers' perceptions of the chronic sorrow phenomenon? Seven biological mothers of children who have multiple disabilities were interviewed on two…

  1. The Phenomenon of Withdrawal in Relation to the Aging Process: A Developmental Perspective.

    ERIC Educational Resources Information Center

    McMordie, William R.

    1981-01-01

    Challenges the disengagement theory of adaptation in the aging process. Suggests that the withdrawal phenomenon exhibited by the elderly simply reflects reduced environmental opportunities for social interaction. Views interpersonal intimacy as the key to satisfactory adjustment. Presents a longitudinal developmental approach to the development of…

  2. On the Cause of University Students' Cheating Phenomenon from the Perspective of Albert Bandura's Reciprocal Determinism

    ERIC Educational Resources Information Center

    Run-xian, Zhou; Xiao-pin, Zhou

    2007-01-01

    In recent years, "cheating" becomes a prevalent social phenomenon among the university students, which result in a bad influence to the quality of higher education, to the healthy growth of the university students, and to the social morale. To solve this problem, the key is to scoop out the root reason and get rid of it thoroughly. The emergence…

  3. Conflicts and Contestations. Rural Populations' Perspectives on the Second Homes Phenomenon

    ERIC Educational Resources Information Center

    Rye, Johan Fredrik

    2011-01-01

    In response to demands to restructure and diversify their economies, many rural communities have welcomed the expanding phenomenon of second homes. However, while the second home owners bring new resources to the host communities, the literature also suggests that large second home populations in rural communities provide fertile ground for a…

  4. The "Stepping Stone Phenomenon": Exploring the Role of Positive Attrition at an Early College Entrance Program

    ERIC Educational Resources Information Center

    Heilbronner, Nancy N.; Connell, Elizabeth E.; Dobyns, Sally M.; Reis, Sally M.

    2010-01-01

    This study explored the differences between students who remained at one early college acceleration program and those who left. Students who left appeared to seek what they perceived as a greater academic challenge or more specialized academic majors than were provided by the host college, a phenomenon that lends credence to the notion of positive…

  5. Social violence: a case for classification as a sub-phenomenon of community in the ICNP.

    PubMed

    Coler, M S; Araújo, L do C; Coêlho, A A; de Figueiredo, T M; Freire, M R; Moreira, M E

    2000-03-01

    The study is intended to illustrate that the nursing phenomenon, Violence, exists as a phenomenon of the aggregate and should thus be classified, under the higher level phenomenon, Community, in the International Classification for Nursing Practice (ICNP), published by the International Council of Nurses. This proposition was confirmed during a meeting of an international team of psychiatric nurses to plan reality-based postgraduate modules for the nine countries they represented. Substantiating data, based on the team's module, Violence, clinical investigation and a review of the literature, evolved from a classroom project in north-east Brazil. The Master's Degree nursing students conducted observations and interviews based on identified factors of the phenomenon on children in two municipal day-care centres in targeted neighbourhoods in João Pessoa, Paraíba, Brazil. Data were gleaned from observations and verbalizations regarding their individual drawings depicting sadness and happiness, from school records and observations of these children by their teachers. The data, evolving from the time-limited classroom project, are too sparse to be considered valid, but pave the road for further studies. Professional and lay-literature substantiates the occurrence of violence in the Brazilian society.

  6. The Mozart Effect: Musical Phenomenon or Musical Preference? A More Ecologically Valid Reconsideration

    ERIC Educational Resources Information Center

    Cassity, Hope Daniels; Henley, Tracy B.; Markley, Robert P.

    2007-01-01

    The "Mozart effect" is the reported phenomenon of increased spatial abilities after listening to that composer's music. However, subsequent research suggests that the Mozart effect may be an artifactual consequence of heightened arousal and mood rather than the music of Mozart per se (e.g., Thompson, Schellenberg, & Husain, 2001). The present…

  7. The Multilingual Education (MLE) Network Phenomenon: Advocacy and Action for Minoritized Language Communities

    ERIC Educational Resources Information Center

    Trudell, Barbara

    2014-01-01

    This article examines a new phenomenon in language activism variously called the multilingual education working group or the multilingual education network, and abbreviated as MLEN. After an analysis of the conceptual and organizational contexts for these activist groups, the six MLENs in existence as of 2013 are described. The groups are then…

  8. The Initial Conceptions for Earthquakes Phenomenon for Moroccan Students of the First Year Secondary College

    ERIC Educational Resources Information Center

    Eddif, Aâtika; Touir, Rachid; Majdoubi, Hassan; Larhzil, Hayat; Mousaoui, Brahim; Ahmamou, Mhamed

    2015-01-01

    This work proposes initially to identify the initial conceptions of Moroccan students in the first year of secondary college about the notion of earthquakes. The used methodology is based on a questionnaire addressed to students of life science and Earth in Meknes city, before any official teaching about the said phenomenon. The obtained results…

  9. A correlated-cluster model and the ridge phenomenon in hadron-hadron collisions

    NASA Astrophysics Data System (ADS)

    Sanchis-Lozano, Miguel-Angel; Sarkisyan-Grinbaum, Edward

    2017-03-01

    A study of the near-side ridge phenomenon in hadron-hadron collisions based on a cluster picture of multiparticle production is presented. The near-side ridge effect is shown to have a natural explanation in this context provided that clusters are produced in a correlated manner in the collision transverse plane.

  10. Perceived Inadequacy: A Study of the Imposter Phenomenon among College and Research Librarians

    ERIC Educational Resources Information Center

    Clark, Melanie; Vardeman, Kimberly; Barba, Shelley

    2014-01-01

    The Imposter Phenomenon (IP) is an observed anxiety caused by an individual's feelings of fraudulence, fear of being exposed as a fraud, and inability to internalize personal achievement. This study measures the incidence of the IP among librarians at college and research institutions in the United States and Canada and seeks to identify factors…

  11. Education of Tolerant Personality of a Future Specialist as the Social-Pedagogical Phenomenon

    ERIC Educational Resources Information Center

    Kaztaevna, Tokkulinova Gulnar; Omarovna, Assylova Raushan; Askerkhanovna, Tleuzhanova Kuralay; Zhanarbekovna, Burkitbaeva Anar; Erezhepovna, Kazhieva Nurgul

    2015-01-01

    The article raises the problem of education of tolerance in students as a social and pedagogical phenomenon and stresses the importance and urgency of this problem at the present stage of society development. The author examines the theoretical basis and the possibility of development of tolerant relations in vocational education as a special…

  12. How Families Experience the Phenomenon of Adolescent Pregnancy and Parenting: Implications for Family Therapists and Educators

    ERIC Educational Resources Information Center

    Boyer, Glenda J.

    2012-01-01

    The purpose of this qualitative study was to describe how family members experience the phenomenon of adolescent pregnancy and parenting in the family unit, over time, and to examine the meanings family members attach to the experience. The participants were six nuclear families (20 individuals) of six adolescent mothers who had previously…

  13. Phenomenon of Energy Focusing in Explosive Systems which include High Modulus Elastic Elements

    NASA Astrophysics Data System (ADS)

    Balagansky, I.; Hokamoto, K.; Manikandan, P.; Matrosov, A.; Stadnichenko, I.; Miyoshi, H.

    2009-06-01

    The phenomenon was observed in a passive HE charge of cast Comp. B without cumulative shape under shock wave loading by explosion of an active HE charge through water after preliminary compression by a leading wave in silicon carbide insert. The phenomenon manifested itself as a hole in identification steel specimen with depth of about 10 mm and diameter of about 5 mm. Results of experiments on studying of conditions of implementation of this phenomenon for SEP and Comp. B are presented. For each HE a number of experiments has been executed at various length of silicon carbide insert. Presence or absence of a hole in the steel specimen was determined. Also a number of optical registrations of process in framing mode with record step of 1 μs have been executed. Digital video camera SHIMADZU HPV-1 was used for optical registration. Results of experiments testify that the phenomenon is reproduced both for SEP, and for Comp. B. Focusing process is observed in conditions close to critical conditions of transfer of a detonation from active to a passive HE charge.

  14. How Academic Leaders Conceptualize the Phenomenon of Faculty Performance Appraisal Practices

    ERIC Educational Resources Information Center

    Soo Kim, Tatum

    2016-01-01

    This dissertation addresses the phenomenon of how academic leaders conceptualize faculty performance practices. Qualitative research methods were used to explore the experiences of 11 academic leaders from 4-year higher education institutions in the metropolitan area of New York, NY. Each academic leader had direct responsibility for faculty…

  15. Codependency: a concomitant field of interest in research into the phenomenon caring.

    PubMed

    van der Wal, D

    1996-12-01

    The growing popularity of caring is evident throughout the nursing profession. Research into the phenomenon caring, however, necessitates that caring as an ethic be distinguished from pseudo caring actions and experiences. Codependence and codependency are proposed as being of a pseudo-caring nature. Research interest into this field of study needs to be kindled.

  16. Helicopter Parents of Community College Students: How Community College Professionals Operationally Define and Address This Phenomenon

    ERIC Educational Resources Information Center

    Hightower, Helen C.

    2014-01-01

    This study examined whether the phenomenon of "parental over-involvement" occurred in the Virginia Community College System. Concern has been expressed in the popular and academic literature in recent years over the increased level of parental involvement at four year institutions whose student bodies consist almost exclusively of…

  17. An Emergent Phenomenon of American Indian Secondary Students' Career Development Process

    ERIC Educational Resources Information Center

    Flynn, Stephen V.; Duncan, Kelly J.; Evenson, Lori L.

    2013-01-01

    Nine single-race American Indian secondary students' career development experiences were examined through a phenomenological methodology. All 9 participants were in the transition period starting in late secondary school (age 18). Data sources included individual interviews and journal analysis. The phenomenon of American Indian secondary…

  18. Approaching Participation in School-Based Mathematics as a Cross-Setting Phenomenon

    ERIC Educational Resources Information Center

    Jackson, Kara

    2011-01-01

    This article reports on an ethnographic study of a 10-year-old's pursuit of school-based mathematics across school and home to suggest that participating in school-based mathematics is a cross-setting phenomenon in at least 2 ways. First, I illustrate how accomplishing school-based mathematics literally extends into the home and how individuals…

  19. The Role of Social Influence in Anxiety and the Imposter Phenomenon

    ERIC Educational Resources Information Center

    Fraenza, Christy B.

    2016-01-01

    High anxiety levels have been associated with high levels of the imposter phenomenon (IP), a negative experience of feeling like a fraud. This study was designed to explore IP among graduate students and to determine whether a difference exists between online graduate students and traditional graduate students. The theoretical foundation of this…

  20. The illusory-letters phenomenon: an illustration of graphemic restoration in visual word recognition.

    PubMed

    Jordan, T R; Thomas, S M; Scott-Brown, K C

    1999-01-01

    We present a demonstration of word perception in which stimuli containing very few letters (just 50% of their original number) are presented for unlimited durations and yet are seen unequivocally as complete words. The phenomenon suggests that recognition of words can be achieved even when perception of their component letters is prevented.

  1. Intensification of the phenomenon of violence in the family environment of teenagers.

    PubMed

    Latalski, Maciej; Skórzyńska, Hanna; Pacian, Anna; Sokół, Marlena

    2004-01-01

    Childhood and adolescence are the periods of life when the experience of violence accumulates. As socially weaker individuals, children and teenagers are exposed to violence. The factors that increase the risk of child maltreatment include, above all, social and cultural factors and the stress that family suffer from. The literature on this subject distinguishes four categories of child maltreatment, namely: emotional, physical, negligence and sexual abuse. The survey involved 250 representatives of high school teenagers aged 15-20, including 145 girls and 105 boys. The research method was the survey estimating the Scale of Battered Child Syndrome (for teenagers and adults). The results show that a big group of teenagers admitted to having experienced at least one of four kinds of domestic violence. The group is not uniform, however, and the socio-cultural factors that affect the kind and intensification of the phenomenon of violence have been revealed. The most frequent reasons for using violence are: low level of education, unemployment of parents and material status connected with this fact, low frequency of attendance to religious services, alcohol abuse, and place of living. On account of the intensification of the phenomenon of violence in the domestic environment and both direct and distant consequences of the phenomenon in the form of mental and physical disorders of individuals as well as the dangers for the proper development of the society that result from it, there is a need to continue doing research on this phenomenon.

  2. Factors Influencing the ABT Phenomenon among Graduate Students in a Master Program in Mexico

    ERIC Educational Resources Information Center

    Gonzalez-Castillo, Vicente; Cisneros-Cohernour, Edith J.

    2007-01-01

    This paper presents the findings of a study examining the factors that influence the ABT phenomenon (all but thesis) among graduate students of a Master in Education program in the Southeast of Mexico. Findings of the study identified individual and organizational factors influencing ABT. The study allowed for a better understanding about how…

  3. Role of parietal and principal gastric mucosa cells in the phenomenon of concentration of aluminum and indium.

    PubMed

    Maghraoui, Samira; Ayadi, Ahlem; Audinot, Jean-Nicolas; Ben Ammar, Aouatef; Jaafoura, Mohamed-Habib; El Hili, Ali; Migeon, Henri-Noël; Tekaya, Leila

    2012-02-01

    The subcellular behavior of aluminum and indium, used in medical and industrial fields, was studied in the gastric mucosa and the liver after their intragastric administration to rats, using, two of the most sensitive methods of observation and microanalysis, the transmission electron microscopy, and the secondary ion mass spectrometry. The ultrastructural study showed the presence of electron dense deposits, in the lysosomes of parietal and principal gastric mucosa cells but no loaded lysosomes were observed in the different studied hepatic territories. The microanalytical study allowed the identification of the chemical species present in those deposits as aluminum or indium isotopes and the cartography of their distribution. No modification was observed in control rats tissues. In comparison to previous studies describing the mechanism of aluminum concentration in the gastric mucosa and showing that this element was concentrated in the lysosomes of fundic and antral human gastric mucosa, our study provided additional informations about the types of cells involved in the phenomenon of concentration of aluminum and indium, which are the parietal and the principal cells of the gastric mucosa. Our study demonstrated that these cells have the ability to concentrate selectively aluminum and indium in their lysosomes, as a defensive reaction against intoxication by foreign elements.

  4. Interaction of a flame front with its self-generated flow in an enclosure; The tulip flame phenomenon

    SciTech Connect

    Gonzalez, M.; Borghi, R.; Saouab, A. )

    1992-02-01

    This paper reports on the propagation of a flame front under nonturbulent condition in a closed tube ignited at one end which is numerically investigated using a computing procedure based on finite volumes technique and devoted to two-dimensional, compressible, reacting flows. A global one-step reaction for the chemical process and an Arrhenius law for fuel consumption are assumed. The detailed analysis of the results of computations in which wall friction, tube aspect ratio and initial flame configuration are varied allows to highlight the influence of different parameters and to get more insight into the tulip-shaped flame phenomenon. In particular, Darrieus-landau instability is examined by comparing the shape variations of an initially perturbed flat front in a tube closed at both ends to those in a tube in which the ignition end is open while the opposite one is closed. Attention is also given to the computed flame generated flowfield; the flame front-confined flow interaction is specially scrutinized. Furthermore, the oscillatory acoustic regime occurring during tulip flame appearance, as well as the collapse of the tulip shape in tubes of large aspect ratio, already experimentally put into evidence but never numerically addressed, have also been simulated and discussed.

  5. A proposed model for examining the interference phenomenon between concurrent aerobic and strength training.

    PubMed

    Docherty, D; Sporer, B

    2000-12-01

    A review of the current research on the interference phenomenon between concurrent aerobic and strength training indicates modest support for the model proposed in this article. However, it is clear that without a systematic approach to the investigation of the phenomenon there is lack of control and manipulation of the independent variables, which makes it difficult to test the validity of the model. To enhance the understanding of the interference phenomenon, it is important that researchers are precise and deliberate in their choice of training protocols. Clear definition of the specific training objectives for strength (muscle hypertrophy or neural adaptation) and aerobic power (maximal aerobic power or anaerobic threshold) are required. In addition, researchers should equate training volumes as much as possible for all groups. Care needs to be exercised to avoid overtraining individuals. There should be adequate recovery and regeneration between the concurrent training sessions as well as during the training cycle. The model should be initially tested by maintaining the same protocols throughout the duration of the study. However, it is becoming common practice to use a periodised approach in a training mesocycle in which there is a shift from high volume and moderate intensity training to tower volume and higher intensity. The model should be evaluated in the context of a periodised mesocycle provided the investigators are sensitive to the potential impact of the loading parameters on the interference phenomenon. It may be that the periodised approach is one way of maintaining the training stimulus and minimising the amount of interference. The effects of gender, training status, duration and frequency of training, and the mode of training need to be regarded as potential factors effecting the training response when investigating the interference phenomenon. Other experimental design factors such as unilateral limb training or training the upper body for one

  6. Enhancing chemical reactions

    DOEpatents

    Morrey, John R.

    1978-01-01

    Methods of enhancing selected chemical reactions. The population of a selected high vibrational energy state of a reactant molecule is increased substantially above its population at thermal equilibrium by directing onto the molecule a beam of radiant energy from a laser having a combination of frequency and intensity selected to pump the selected energy state, and the reaction is carried out with the temperature, pressure, and concentrations of reactants maintained at a combination of values selected to optimize the reaction in preference to thermal degradation by transforming the absorbed energy into translational motion. The reaction temperature is selected to optimize the reaction. Typically a laser and a frequency doubler emit radiant energy at frequencies of .nu. and 2.nu. into an optical dye within an optical cavity capable of being tuned to a wanted frequency .delta. or a parametric oscillator comprising a non-centrosymmetric crystal having two indices of refraction, to emit radiant energy at the frequencies of .nu., 2.nu., and .delta. (and, with a parametric oscillator, also at 2.nu.-.delta.). Each unwanted frequency is filtered out, and each desired frequency is focused to the desired radiation flux within a reaction chamber and is reflected repeatedly through the chamber while reactants are fed into the chamber and reaction products are removed therefrom.

  7. Algorithm for reaction classification.

    PubMed

    Kraut, Hans; Eiblmaier, Josef; Grethe, Guenter; Löw, Peter; Matuszczyk, Heinz; Saller, Heinz

    2013-11-25

    Reaction classification has important applications, and many approaches to classification have been applied. Our own algorithm tests all maximum common substructures (MCS) between all reactant and product molecules in order to find an atom mapping containing the minimum chemical distance (MCD). Recent publications have concluded that new MCS algorithms need to be compared with existing methods in a reproducible environment, preferably on a generalized test set, yet the number of test sets available is small, and they are not truly representative of the range of reactions that occur in real reaction databases. We have designed a challenging test set of reactions and are making it publicly available and usable with InfoChem's software or other classification algorithms. We supply a representative set of example reactions, grouped into different levels of difficulty, from a large number of reaction databases that chemists actually encounter in practice, in order to demonstrate the basic requirements for a mapping algorithm to detect the reaction centers in a consistent way. We invite the scientific community to contribute to the future extension and improvement of this data set, to achieve the goal of a common standard.

  8. Modeling of surface reactions

    SciTech Connect

    Ray, T.R.

    1993-01-01

    Mathematical models are used to elucidate properties of the monomer-monomer and monomer-dimer type chemical reactions on a two-dimensional surface. The authors use mean-field and lattice gas models, detailing similarities and differences due to correlations in the lattice gas model. The monomer-monomer, or AB surface reaction model, with no diffusion, is investigated for various reaction rates k. Study of the exact rate equations reveals that poisoning always occurs if the adsorption rates of the reactants are unequal. If the adsorption rates of the reactants are equal, simulations show slow poisoning, associated with clustering of reactants. This behavior is also shown for the two-dimensional voter model. The authors analyze precisely the slow poisoning kinetics by an analytic treatment for the AB reaction with infinitesimal reaction rate, and by direct comparison with the voter model. They extend the results to incorporate the effects of place-exchange diffusion, and they compare the AB reaction with infinitesimal reaction rate and no diffusion to the voter model with diffusion at rate 1/2. They also consider the relationship of the voter model to the monomer-dimer model, and investigate the latter model for small reaction rates. The monomer-dimer, or AB[sub 2] surface reaction model is also investigated. Specifically, they consider the ZGB-model for CO-oxidation, and in generalizations of this model which include adspecies diffusion. A theory of nucleation to describe properties of non-equilibrium first-order transitions, specifically the evolution between [open quote]reactive[close quote] steady states and trivial adsorbing states, is derived. The behavior of the [open quote]epidemic[close quote] survival probability, P[sub s], for a non-poisoned patch surrounded by a poisoned background is determined below the poisoning transition.

  9. Cycloaddition reactions of ICNO

    NASA Astrophysics Data System (ADS)

    Pasinszki, Tibor; Krebsz, Melinda; Hajgató, Balázs

    2009-05-01

    The mechanism and selectivity of cycloaddition reactions of iodonitrile oxide, ICNO, have been studied with theoretical methods for the first time using MR-AQCC coupled-cluster and B3LYP DFT methods. Calculations have predicted that the favoured ICNO dimerisation process is a multi-step reaction to diiodofuroxan involving dinitrosoethylene-like intermediates. The ICNO cycloaddition with nitriles and ethynyl derivatives is a synchronous process favouring the formation of 1,2,4-oxadiazole and 1,2-oxazole derivatives, respectively. The cycloaddition reactions of ICNO have been studied experimentally by generating ICNO from AgCNO and iodine. Diiodofuroxan is obtained, however, even at the presence of nitriles.

  10. NEUTRONIC REACTION SYSTEM

    DOEpatents

    Wigner, E.P.

    1963-09-01

    A nuclear reactor system is described for breeding fissionable material, including a heat-exchange tank, a high- and a low-pressure chamber therein, heat- exchange tubes connecting these chambers, a solution of U/sup 233/ in heavy water in a reaction container within the tank, a slurry of thorium dioxide in heavy water in a second container surrounding the first container, an inlet conduit including a pump connecting the low pressure chamber to the reaction container, an outlet conduit connecting the high pressure chamber to the reaction container, and means of removing gaseous fission products released in both chambers. (AEC)

  11. Reaction and diffusion in turbulent combustion

    SciTech Connect

    Pope, S.B.

    1993-12-01

    The motivation for this project is the need to obtain a better quantitative understanding of the technologically-important phenomenon of turbulent combustion. In nearly all applications in which fuel is burned-for example, fossil-fuel power plants, furnaces, gas-turbines and internal-combustion engines-the combustion takes place in a turbulent flow. Designers continually demand more quantitative information about this phenomenon-in the form of turbulent combustion models-so that they can design equipment with increased efficiency and decreased environmental impact. For some time the PI has been developing a class of turbulent combustion models known as PDF methods. These methods have the important virtue that both convection and reaction can be treated without turbulence-modelling assumptions. However, a mixing model is required to account for the effects of molecular diffusion. Currently, the available mixing models are known to have some significant defects. The major motivation of the project is to seek a better understanding of molecular diffusion in turbulent reactive flows, and hence to develop a better mixing model.

  12. Bad Reaction to Cosmetics?

    MedlinePlus

    ... Devices Radiation-Emitting Products Vaccines, Blood & Biologics Animal & Veterinary Cosmetics Tobacco Products For Consumers Home For Consumers ... Reactions From Cosmetics More in Consumer Updates Animal & Veterinary Children's Health Cosmetics Dietary Supplements Drugs Food Medical ...

  13. Reactor for exothermic reactions

    DOEpatents

    Smith, Jr., Lawrence A.; Hearn, Dennis; Jones, Jr., Edward M.

    1993-01-01

    A liquid phase process for oligomerization of C.sub.4 and C.sub.5 isoolefins or the etherification thereof with C.sub.1 to C.sub.6 alcohols wherein the reactants are contacted in a reactor with a fixed bed acid cation exchange resin catalyst at an LHSV of 5 to 20, pressure of 0 to 400 psig and temperature of 120.degree. to 300.degree. F. Wherein the improvement is the operation of the reactor at a pressure to maintain the reaction mixture at its boiling point whereby at least a portion but less than all of the reaction mixture is vaporized. By operating at the boiling point and allowing a portion of the reaction mixture to vaporize, the exothermic heat of reaction is dissipated by the formation of more boil up and the temperature in the reactor is controlled.

  14. Untoward penicillin reactions

    PubMed Central

    Guthe, T.; Idsöe, O.; Willcox, R. R.

    1958-01-01

    The literature on untoward reactions following the administration of penicillin is reviewed. These reactions, including a certain number of deaths which have been reported, are of particular interest to health administrations and to WHO in view of the large-scale programmes for controlling the treponematoses which are now under way—programmes affecting millions of people in many parts of the world. The most serious problems are anaphylactic sensitivity phenomena and superinfection or cross-infection with penicillin-resistant organisms, and the reactions involved range in intensity from the mildest to the fatal; the incidence of the latter is estimated at 0.1-0.3 per million injections. The authors point out that with increasing use of penicillin, more persons are likely to become sensitized and the number of reactions can therefore be expected to rise. The best prevention against such an increase is the restriction of the unnecessary use of penicillin. PMID:13596877

  15. Translated chemical reaction networks.

    PubMed

    Johnston, Matthew D

    2014-05-01

    Many biochemical and industrial applications involve complicated networks of simultaneously occurring chemical reactions. Under the assumption of mass action kinetics, the dynamics of these chemical reaction networks are governed by systems of polynomial ordinary differential equations. The steady states of these mass action systems have been analyzed via a variety of techniques, including stoichiometric network analysis, deficiency theory, and algebraic techniques (e.g., Gröbner bases). In this paper, we present a novel method for characterizing the steady states of mass action systems. Our method explicitly links a network's capacity to permit a particular class of steady states, called toric steady states, to topological properties of a generalized network called a translated chemical reaction network. These networks share their reaction vectors with their source network but are permitted to have different complex stoichiometries and different network topologies. We apply the results to examples drawn from the biochemical literature.

  16. Common Reactions After Trauma

    MedlinePlus

    ... Loss of intimacy or feeling detached Recovery from stress reactions Turn to your family and friends when ... someone is thinking about killing themselves, call the Suicide Prevention Lifeline 1-800-273-TALK (8255) http:// ...

  17. Reaction wheel assembly

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The fabrication and testing of three reaction wheels with associated drive and system monitoring electronics and brushless dc spin motors are discussed; the wheels are intended for use in a teleoperator simulator. Test results are included as graphs.

  18. Reactor for exothermic reactions

    DOEpatents

    Smith, L.A. Jr.; Hearn, D.; Jones, E.M. Jr.

    1993-03-02

    A liquid phase process is described for oligomerization of C[sub 4] and C[sub 5] isoolefins or the etherification thereof with C[sub 1] to C[sub 6] alcohols wherein the reactants are contacted in a reactor with a fixed bed acid cation exchange resin catalyst at an LHSV of 5 to 20, pressure of 0 to 400 psig and temperature of 120 to 300 F. Wherein the improvement is the operation of the reactor at a pressure to maintain the reaction mixture at its boiling point whereby at least a portion but less than all of the reaction mixture is vaporized. By operating at the boiling point and allowing a portion of the reaction mixture to vaporize, the exothermic heat of reaction is dissipated by the formation of more boil up and the temperature in the reactor is controlled.

  19. Oral Hypersensitivity Reactions

    MedlinePlus

    ... often flavored with agents like cinnamon, peppermint or menthol, which can trigger hypersensitivity reactions in susceptible individuals. ... potential allergens such as cinnamon, peppermint, eugenol and menthol. Even dental floss and denture cleansers may contain ...

  20. Iodine Clock Reaction.

    ERIC Educational Resources Information Center

    Mitchell, Richard S.

    1996-01-01

    Describes a combination of solutions that can be used in the study of kinetics using the iodine clock reaction. The combination slows down degradation of the prepared solutions and can be used successfully for several weeks. (JRH)

  1. Response reactions: equilibrium coupling.

    PubMed

    Hoffmann, Eufrozina A; Nagypal, Istvan

    2006-06-01

    It is pointed out and illustrated in the present paper that if a homogeneous multiple equilibrium system containing k components and q species is composed of the reactants actually taken and their reactions contain only k + 1 species, then we have a unique representation with (q - k) stoichiometrically independent reactions (SIRs). We define these as coupling reactions. All the other possible combinations with k + 1 species are the coupled reactions that are in equilibrium when the (q - k) SIRs are in equilibrium. The response of the equilibrium state for perturbation is determined by the coupling and coupled equilibria. Depending on the circumstances and the actual thermodynamic data, the effect of coupled equilibria may overtake the effect of the coupling ones, leading to phenomena that are in apparent contradiction with Le Chatelier's principle.

  2. Chemisorption And Precipitation Reactions

    EPA Science Inventory

    The transport and bioavailability of chemical components within soils is, in part, controlled by partitioning between solids and solution. General terms used to describe these partitioning reactions include chemisorption and precipitation. Chemisorption is inclusive of the suit...

  3. An Illuminating Reaction.

    ERIC Educational Resources Information Center

    Matthews, Catherine E.

    1996-01-01

    Describes the use of carbide lights as an excellent mechanism for introducing or reviewing many basic chemistry concepts including elements and compounds, endothermic and exothermic reactions, physical and chemical changes, and balancing chemical equations. (JRH)

  4. [Occurrence of drug reactions].

    PubMed

    Pastorello, E; Qualizza, R M; Luraghi, M T; Ispano, M; Villa, A M; Ortolani, C; Zanussi, C

    1986-01-01

    The aim of this prospective study was to evaluate the incidence of allergic reactions to drugs compared to other kinds of medical emergencies admitted to the main Hospital in Milan during a 6 months period. At the same time we drew a list of drugs most frequently involved in allergic reactions, and a list of the most frequent symptoms. Using special forms, the medical staff collected patients' data: age, history of atopy, identification of the drug causing the reaction, and any previous reactions. Among 11,407 cases of medical emergencies, we found 163 (1.43%) patients showing drug reactions: the mean age was 27.3; 58.90% were female; atopy was present in 16.56%. The drugs most frequently involved were: pyrazon group (22%); ASA (20.86%); penicillin and derivatives (9.20%); sulfa drugs (6.14%); group B vitamins (4.30%); tetanus toxoid (4.30%); hyposensitizing extracts (3.68%); propionic acid derivatives (2.46%); paracetamol (1.84%); indomethacin (1.23%); rifampicin (1.23%); erythromycin (1.23%); glafenine (1.23%); others (17.80%). Urticaria and/or angioedema were the most frequent symptoms (86.51%), then anaphylactic shock (9.81%) and asthma (3.68%) with regard to anaphylactic shock only 6.20% of the patients had had a previous reaction to the same drug. From these data we can see that the incidence of drug reactions is very low compared to other medical emergencies; penicillin evidenced fewer reactions than expected, while the pyrazon group and ASA confirmed the data from literature.

  5. Anaphylactoid reaction to ethanol.

    PubMed

    Kelso, J M; Keating, M U; Squillace, D L; O'Connell, E J; Yunginger, J W; Sachs, M I

    1990-05-01

    We studied a 14-year-old boy who developed a pruritic rash and facial swelling after ingestion of beer or wine. A blinded challenge with purified ethanol was positive demonstrating ethanol itself to be the offending agent. An IgE-mediated reaction to ethanol or one of its metabolites as a hapten is possible, or the reaction may involve unusual metabolism of ethanol with accumulation of acetaldehyde and/or direct mast cell degranulation.

  6. Oxygen evolution reaction catalysis

    DOEpatents

    Haber, Joel A.; Jin, Jian; Xiang, Chengxiang; Gregoire, John M.; Jones, Ryan J.; Guevarra, Dan W.; Shinde, Aniketa A.

    2016-09-06

    An Oxygen Evolution Reaction (OER) catalyst includes a metal oxide that includes oxygen, cerium, and one or more second metals. In some instances, the cerium is 10 to 80 molar % of the metals in the metal oxide and/or the catalyst includes two or more second metals. The OER catalyst can be included in or on an electrode. The electrode can be arranged in an oxygen evolution system such that the Oxygen Evolution Reaction occurs at the electrode.

  7. Reactions during infiltration of graphite fibers by molten Al-Ti alloy

    SciTech Connect

    Jarfors, A.E.W.; Wallinder, M.; Fredriksson, H. . Dept. of Materials Processing)

    1993-11-01

    The infiltration sequence of graphite fibers with liquid aluminum alloyed with titanium was studied. The titanium concentration was chosen such that a severe reaction occurred between the fibers and the melt. Aluminum carbide and titanium carbide, as well as an aluminide phase were formed. The phenomenon occurring during the infiltration sequence was explained with the aid of the ternary-phase diagram Al-Ti-C. The effect of the reaction on the infiltration height is discussed.

  8. Dermatophytid in tinea capitis: rarely reported common phenomenon with clinical implications.

    PubMed

    Cheng, Nancy; Rucker Wright, Dakara; Cohen, Bernard A

    2011-08-01

    Tinea capitis may be associated with a dermatophytid, which appears as a disseminated eczematous eruption. This phenomenon may occur before or after initiation of systemic antifungal drug therapy and is not an indication for stopping medication. We present here a series of cases that involve 5 children with tinea capitis who developed a dermatophytid before or during the course of their management. In each child, the eruption resolved despite continuation of oral antifungal therapy. Our experience suggests that dermatophytid secondary to tinea capitis is much more common than reported. Furthermore, parents and clinicians frequently mistake dermatophytid for drug allergy. Recognition of this phenomenon, distinction of dermatophytid from drug allergy, and continuation of systemic treatment is essential for clearing the infection and dermatophytid.

  9. Influence of Doppler effect on the phenomenon of electromagnetically induced transparency

    NASA Astrophysics Data System (ADS)

    Tao, Qiyong; Zhang, Guiyin; Zheng, Haiming

    2016-11-01

    Electromagnetically induced transparency (EIT) is a significant nonlinear optical phenomenon. Based on the theory of density matrix equation, we presented the influence of Doppler effect on EIT. A cascade type three-level system and Na atomic vapor is adopted during the course. The results showed that EIT is determined by Rabi frequency of the couple and probing field. It is independent of temperature usually. But when we take Doppler effect into account, it is found that the full transparency appeared at the condition of ΩP=0.01GHz, ΩC=1GHz will vary with temperature. An obvious transparent window can be observed only when the temperature is less than 50K. With the increase of temperature, EIT phenomenon disappeared quickly. At room temperature, we can see that the double peaks of Aulter-Townes will instead of the EIT transparent window as Rabi frequency of the couple field is larger than 1.5GHz.

  10. Investigation of the Temperature Hysteresis Phenomenon of a Loop Heat Pipe

    NASA Technical Reports Server (NTRS)

    Kaya, Tarik; Ku, Jentung; Hoang, Triem; Cheung, Mark K.

    1999-01-01

    The temperature hysteresis phenomenon of a Loop Heat Pipe (LHP) was experimentally investigated. The temperature hysteresis was identified by the fact that the operating temperature depends upon not only the imposed power but also the previous history of the power variation. The temperature hysteresis could impose limitations on the LHP applications since the LHP may exhibit different steady-state operating temperatures at a given power input even when the condenser sink temperature remains unchanged. In order to obtain insight to this phenomenon, a LHP was tested at different elevations and tilts by using an elaborated power profile. A hypothesis was suggested to explain the temperature hysteresis. This hypothesis explains well the experimental observations. Results of this study provide a better understanding of the performance characteristics of the LHPS.

  11. No reflow phenomenon in percutaneous coronary interventions in ST-segment elevation myocardial infarction.

    PubMed

    Gupta, Sanjiv; Gupta, Madan Mohan

    2016-01-01

    Percutaneous coronary intervention (PCI) is effective in opening the infarct related artery and restoring thrombolysis in myocardial infarction flow 3 (TIMI-flow 3) in large majority of ST-elevation myocardial infarction (STEMI). However there remain a small but significant proportion of patients, who continue to manifest diminished myocardial reperfusion despite successful opening of the obstructed epicardial artery. This phenomenon is called no-reflow. Clinically it manifests with recurrence of chest pain and dyspnea and may progress to cardiogenic shock, cardiac arrest, serious arrhythmias and acute heart failure. No reflow is regarded as independent predictor of death or recurrent myocardial infarction. No reflow is a multi-factorial phenomenon. However micro embolization of atherothrombotic debris during PCI remains the principal mechanism responsible for microvascular obstruction. This review summarizes the pathogenesis, diagnostic methods and the results of various recent randomized trials and studies on the prevention and management of no-reflow.

  12. Organizational Tonypandy: Lessons from a Quarter Century of the Groupthink Phenomenon.

    PubMed

    Fuller; Aldag

    1998-02-01

    We adopt the role of devil's advocate, arguing that the quarter-century experience with groupthink represents an unfortunate episode in the history of group problem solving research. In view of the facts that there has been remarkably little empirical support for the groupthink phenomenon, that the phenomenon rests on arguable assumptions, that published critiques of groupthink have generally been ignored by groupthink researchers, and that groupthink is presented as fact in journal articles and textbooks, we see continued advocacy of groupthink as a form of organizational Tonypandy, in which knowledgeable individuals fail to speak out against widely accepted but erroneous beliefs. We explore the nature and causes of this Tonypandy and encourage researchers to cast off the artificial determinism and constraints of the groupthink model and instead seek to inform the general group decision making literature. Copyright 1998 Academic Press.

  13. FMCW CSAR Doppler shifting correction and the layover phenomenon analysising at a new received signal model

    NASA Astrophysics Data System (ADS)

    Song, Depeng; Qu, Yi; Xie, Yuehui

    2016-10-01

    Because of go-stop mode not applying to FMCW CSAR (frequency modulated continuous wave circular synthetic aperture radar), received signal include Doppler shifting result from the radar fly in one period, which have a bad effect on the quality of imaging in wide-field FMCW CSAR. However the compensation functions of liner SAR are not suitable for CSAR. To solve the problem, the paper rebuild a received mode and elicit the Doppler shifting. At the same time, based on the model, the paper analysis the layover phenomenon while obtaining two-dimensional (2D) representations of 3D large scenes due to the wide-field FMCW CSAR and simulate the phenomenon. By the simulation, the effect of the layover can be expressed clearly.

  14. Characterization of Spontaneous Subclavian Steal Phenomenon in a Female Rhesus Macaque (Macaca mulatta)

    PubMed Central

    Ibáñez-Contreras, Alejandra; Hernández-Godínez, Braulio; Perdigón-Castañeda, Gerardo; Tena-Betancourt, Eduardo

    2011-01-01

    In subclavian steal phenomenon (SSP), the subclavian artery develops a stenoocclusive disease proximal to the origin of the vertebral artery, leading to pronounced hemodynamic changes such as arterial flow reversal. Although SSP is a common echographic finding in humans, the phenomenon occurs only rarely in animals; consequently its physiologic features have not been reported previously. Here we describe the clinical and morphologic features of a spontaneous left SSP that was an incidental finding in an 18-y-old female rhesus macaque (Macaca mulatta). Our findings were documented through high-quality imaging studies obtained by using a computerized 3D tomography apparatus and clinical assessment of systolic and diastolic blood pressures. PMID:21640038

  15. Collisional drag may lead to disappearance of wave-breaking phenomenon of lower hybrid oscillations

    SciTech Connect

    Maity, Chandan; Chakrabarti, Nikhil

    2013-01-15

    The inhomogeneity in the magnetic field in a cold electron-ion non-dissipative homogeneous plasma leads to the breaking of lower hybrid modes via phase mixing phenomenon [Maity et al. Phys. Plasmas 19, 102302 (2012)]. In this work, we show that an inclusion of collisional drag force in fluid equations may lead to the disappearance of the wave-breaking phenomenon of lower hybrid oscillations. The nonlinear analysis in Lagrangian variables provides an expression for a critical value of damping rate, above which spikes in the plasma density profile may disappear. The critical damping rate depends on the perturbation and magnetic field inhomogeneity amplitudes as well as the ratio of the magnetic field inhomogeneity and perturbation scale lengths.

  16. Induction of vasospastic attacks despite digital nerve block in Raynaud's disease and phenomenon.

    PubMed

    Freedman, R R; Mayes, M D; Sabharwal, S C

    1989-10-01

    Using a combination of environmental and local cooling, we induced vasospastic attacks of Raynaud's phenomenon in nine of 11 patients with idiopathic Raynaud's disease and in eight of 10 patients with scleroderma. Attacks were defined as occurring if two of the possible three color changes (pallor, cyanosis, and rubor) occurred, and serial photographs were scored by three independent raters. Two fingers on one hand were anesthetized by local injection of lidocaine, and the effectiveness of nerve blocks was verified by plethysmography. The frequency of vasospastic attacks in nerve-blocked fingers was not significantly different from that in the corresponding intact fingers on the contralateral hand. These findings show that the vasospastic attacks of Raynaud's disease and phenomenon can occur without the involvement of efferent digital nerves and argue against the etiologic role of sympathetic hyperactivity.

  17. Modeling and investigation of the channeling phenomenon in downdraft stratified gasifers.

    PubMed

    Allesina, Giulio; Pedrazzi, Simone; Tartarini, Paolo

    2013-10-01

    Downdraft stratified gasifiers seem to be the reactors which are most influenced by loading conditions. Moreover, the larger the reactor is, the higher the possibility to stumble across a channeling phenomenon. This high sensitivity is due to the limited thickness and superficial placement of the flaming pyrolysis layer coupled with the necessity to keep all the zones parallel for a correct running of this kind of gasifier. This study was aimed at modeling and investigating the channeling phenomenon generated by loading condition variations on a 250-kWe nominal power gasification power plant. The experimental campaign showed great variations in most of the plant outputs. These phenomena were modeled on two modified mathematical models obtained from literature. The results of the models confirmed the capability of this approach to predict the channeling phenomena and its dependency on the loading method.

  18. A coupled TH/Neutronics/CRUD framework in prediction of CIPS phenomenon

    SciTech Connect

    Zou, L.; Zhang, H.; Gehin, J.; Kochunas, B.

    2012-07-01

    A coupled TH/Neutronics/CRUD framework, which is able to simulate the CRUD deposits impact on CIPS phenomenon, was described in this paper. The coupling among three essential physics, thermal-hydraulics, CRUD and neutronics described in the framework was implemented by using CFD software STAR-CCM+, developing CRUD module, and using the neutronics code DeCART. The coupling among these codes was implemented by exchanging data between them using intermediate exchange files. A typical 3 by 3 PWR fuel pin problem was solved under this framework and the results were presented. Time-dependent solutions were provided for a 12-month simulation, including CRUD deposits inventory and their distributions on fuel rods, boron hideout amount inside CRUD deposits, as well as power shape changing over time. The results clearly showed the power shape suppression in regions where CRUD deposits exist, which is a clear indication of CIPS phenomenon. (authors)

  19. A COUPLED TH/NEUTRONICS/CRUD FRAMEWORK IN PREDICTION OF CIPS PHENOMENON

    SciTech Connect

    Ling Zou; Hongbin Zhang; Jess Gehin; Brendan Kochunas

    2012-04-01

    A coupled TH/Neutronics/CRUD framework, which is able to simulate the CRUD deposits impact on CIPS phenomenon, was described in this paper. This framework includes the coupling among three essential physics, thermal-hydraulics, CRUD and neutronics. The overall framework was implemented by using the CFD software STAR-CCM+, developing CRUD codes, and using the neutronics code DeCART. The coupling was implemented by exchanging data between softwares using intermediate exchange files. A typical 3 by 3 PWR fuel pin problem was solved under this framework. The problem was solved in a 12 months length period of time. Time-dependent solutions were provided, including CRUD deposits inventory and their distributions on fuels, boron hideout amount inside CRUD deposits, as well as power shape changing over time. The results clearly showed the power shape suppression in regions where CRUD deposits exist, which is a strong indication of CIPS phenomenon.

  20. Improvement in freezing phenomenon of Parkinson's disease after DL-threo-3, 4-dihydroxyphenylserine.

    PubMed

    Ogawa, N; Kuroda, H; Yamamoto, M; Nukina, I; Ota, Z

    1984-06-01

    A 77-year-old man with Parkinson's disease of long standing, under treatment with L-DOPA and benserazide, was administered DL-threo-3, 4-dihydroxyphenylserine (DL-threo-DOPS), a precursor of norepinephrine, for 10 days. With this administration the patient's freezing phenomenon was remarkably improved, and his dysarthria also showed improvement. When DL-threo-DOPS was suspended, the frozen gait returned on the third day to almost the former level, even though he continued to receive L-DOPA and benserazide. After administration of DL-threo-DOPS, the CSF level of 3-methoxy-4-hydroxyphenylglycol (MHPG), a major metabolite of norepinephrine, was 127.5% of the pretreatment level. These observations suggest that DL-threo-DOPS can pass through the blood-brain barrier and change to norepinephrine, and that DL-threo-DOPS may be beneficial in the treatment of the freezing phenomenon of Parkinson's disease.

  1. Scaling in non-stationary time series. (II). Teen birth phenomenon

    NASA Astrophysics Data System (ADS)

    Ignaccolo, M.; Allegrini, P.; Grigolini, P.; Hamilton, P.; West, B. J.

    2004-05-01

    This paper is devoted to the problem of statistical mechanics raised by the analysis of an issue of sociological interest: the teen birth phenomenon. It is expected that these data are characterized by correlated fluctuations, reflecting the cooperative properties of the process. However, the assessment of the anomalous scaling generated by these correlations is made difficult, and ambiguous as well, by the non-stationary nature of the data that shows a clear dependence on seasonal periodicity (periodic component) and an average changing slowly in time (slow component) as well. We use the detrending techniques described in the companion paper [The earlier companion paper], to safely remove all the biases and to derive the genuine scaling of the teen birth phenomenon.

  2. [Analysis of influence factors and control methods on iron release phenomenon in drinking water distribution system].

    PubMed

    Niu, Zhang-bin; Wang, Yang; Zhang, Xiao-jian; He, Wen-Jie; Han, Hong-da; Yin, Pei-jun

    2006-02-01

    Variation rule of iron in drinking water distribution systems was studied, and it was found that the iron released from the scale to the bulk water was the primary reason for iron overstep. The main chemical composition of the scale in cast iron pipe and galvanized steel pipe was iron in a northern city in China. In the drinking water distribution systems, when the value of dissolved oxygen or chlorine residual was low, the iron release phenomenon was severe. The reason for that was the passivation layer of the corrosion scale was destroyed in reductive condition and the result was a great amount of iron in ferrous form was released. According to the research results, the control methods for iron release and 'red water' phenomenon were indicated.

  3. A cognitive architecture account of the visual local advantage phenomenon in autism spectrum disorders.

    PubMed

    van der Helm, Peter A

    2016-09-01

    Ideally, a cognitive architecture is a neurally plausible model that unifies mental representations and cognitive processes. Here, I apply such a model to re-evaluate the local advantage phenomenon in autism spectrum disorders (ASD), that is, the better than typical performance on visual tasks in which local stimulus features are to be discerned. The model takes (a) perceptual organization as a predominantly stimulus-driven process yielding hierarchical stimulus organizations, and (b) attention as predominantly scrutinizing the hierarchical structure of established percepts in a task-driven top-down fashion. This accounts for a dominance of wholes over parts and implies that perceived global structures mask incompatible local features. The model also substantiates that impairments in neuronal synchronization - as found in ASD - reduce the emergence of global structures and, thereby, their masking effect on incompatible features. I argue that this explains the local advantage phenomenon and I discuss implications and suggestions for future research.

  4. The phenomenon of spontaneous regression of numerous flat warts: immunohistological studies.

    PubMed

    Tagami, H; Oguchi, M; Ofuji, S

    1980-05-15

    The phenomenon of systemic regression of numberous flat warts takes place within one month after the sudden onset of spontaneous inflammation in them. In other types of warts, we have never observed such a dramatic regression. We performed a histological study in a total of 51 cases showing this spontaneous inflammation in their flat warts and found a massive mononuclear cell infiltration in all. In 9 cases, a histological study for basophils was carried out but failed to show them among the infiltrating cells despite the strong histological resemblance to contact allergy. An immunofluorescence technique performed in 16 cases demonstrated no specific deposits of immunoglobulins and complement in such inflamed wart tissues except for those which appear to be only a secondary event to inflammation per se. These immunopathological findings further substantiate the concept that cell-mediated mechanisms rather than humoral immunity play a major role in this phenomenon of sudden regression of numerous flat warts.

  5. A PRELIMINARY STUDY ON THE FRACTAL PHENOMENON: “DISCONNECTED+ DISCONNECTED=CONNECTED”

    NASA Astrophysics Data System (ADS)

    Wang, Da; Liu, Shutang; Zhao, Yang

    The well-known Parrondo’s paradox: “losing+losing=winning” [G. P. Harmer and D. Abbott, Parrondo’s paradox, Stat. Sci. 14 (2009) 206-213.] indicated that two games with negative gains can generate a new game with positive gain. By extending the Parrondo’s philosophy into chaos research, it was shown that the periodic alteration of two chaotic dynamics results in an ordered dynamics, that is the phenomenon: “chaos+chaos=order” [J. Almeida, D. Peralta-Salas and M. Romera, Can two chaotic systems give rise to order, Physica D 200 124-132 (2005)]. This paper further extends these researches into fractal research by proposing that two disconnected Julia sets can originate a new connected Julia set via alternating order. This new parrondian paradoxical phenomenon can be stated in the Parrondo’s terms as “disconnected+disconnected=connected”.

  6. Characterization of the anamorphic and frequency dependent phenomenon in Liquid Crystal on Silicon displays

    NASA Astrophysics Data System (ADS)

    Lobato, L.; Lizana, A.; Márquez, A.; Moreno, I.; Iemmi, C.; Campos, J.; Yzuel, M. J.

    2011-04-01

    The diffractive efficiency of Liquid Crystal on Silicon (LCoS) displays can be greatly diminished by the appearance of temporal phase fluctuations in the reflected beam, depolarization effects and also because of phase modulation depths smaller than 2π. In order to maximize the efficiency of the Diffractive Optical Elements (DOEs) implemented in the LCoS device, the Minimum Euclidean Distance principle can be applied. However, not all the diffractive elements can be corrected in the same way due to the anamorphic and frequency dependent phenomenon, which is related to the LCoS response, largely dependending on the period and the spatial orientation of the generated DOE. Experimental evidence for the anamorphic and frequency dependent phenomenon is provided in this paper, as well as a comparative study between the efficiency obtained for binary gratings of different periods

  7. An Interesting Case of Basal Cell Carcinoma with Raynaud's Phenomenon Following Chronic Arsenic Exposure.

    PubMed

    Gulshan, S; Rahman, M J; Sarkar, R; Ghosh, S; Hazra, R

    2016-01-01

    Arsenic is commonly known to be associated with squamous cell carcinoma. Among the lesser known associations is basal cell carcinoma and even rarer is its effect on blood vessels causing peripheral vascular disease. Here we present a case of a 55 yr old man with ulceroproliferative lesions on scalp and forehead along with several hyperpigmented patches on trunk and extremities. He had symptoms suggestive of Raynaud's phenomenon that eventually led to digital gangrene. FNAC was done which was suggestive of basal cell carcinoma. On further enquiry, he was found to reside in an arsenic endemic zone and was investigated for blood arsenic level which was elevated. Punch biopsy from different lesions from body confirmed nodular basal cell carcinoma. Presently the patient has stopped drinking water from the local tubewell. On follow-up he shows improvement of Raynaud's phenomenon and skin lesions.

  8. Combined Thenar and Hypothenar Hammer Syndromes and Raynaud's Phenomenon Successfully Treated with Iloprost.

    PubMed

    Ciapetti, Alessandro; Carotti, Marina; Di Carlo, Marco; Salaffi, Fausto

    2016-01-01

    Thenar and hypothenar hammer syndromes are uncommon conditions characterised by digital ischemia of the hand as a result of repetitive trauma at level of the thenar and/or hypothenar eminence and damage to the radial and/or ulnar arteries, respectively. The symptoms are related to the mechanism of the trauma and a Raynaud's phenomenon can be predominant for a long time. The angiography is the "gold standard" imaging technique which allows to confirm the diagnosis. Therapeutic strategy depends on the type of the lesion and severity of symptoms and includes pharmacological (antithrombotic and thrombolytic drugs) and surgical treatments. The authors present a case of a 53-year-old man, carpenter by profession, with combined thenar and hypothenar hammer syndromes and Raynaud's phenomenon, successfully treated with a short course of intravenous infusion of iloprost.

  9. A New Demonstration of the Illusory Letters Phenomenon: Graphemic Restoration in Arabic Word Perception.

    PubMed

    Jordan, Timothy R; Sheen, Mercedes; AlJassmi, Maryam A; Paterson, Kevin B

    2015-02-01

    The illusory letters phenomenon (ILP) is a unique demonstration that words can be perceived as complete even when letters are physically absent. However, the ILP has only ever been reported for a Latinate language (English), and it is unknown whether the illusion occurs for alphabetic languages with fundamentally different visual properties. Here we report a demonstration of the ILP for Arabic in which stimuli containing only the exterior letters of three-letter Arabic words and a nonsense pattern in the interior position were presented to fluent Arabic readers. Despite being incomplete, participants perceived these stimuli as complete Arabic words with all letters visible in their appropriate positions, and were unable to distinguish between illusory and normal displays. This finding provides an important extension of the original ILP and suggests that alphabetic languages may be widely susceptible to the phenomenon and reading generally may occur as a process augmented by illusory percepts.

  10. Persistence, Disillusionment, and Compliance in Educator Reactions to State School Reform.

    ERIC Educational Resources Information Center

    Goldman, Paul; Conley, David T.

    Educator reticence in some states has exerted a moderating effect on attempts to redesign public schooling. This paper presents findings of a longitudinal study that investigated the phenomenon of educator reaction to systemic state school-reform legislation. Oregon's landmark school-reform legislation, passed in 1991 and revised in 1995, serves…

  11. [Cutaneous adverse drug reactions].

    PubMed

    Lebrun-Vignes, B; Valeyrie-Allanore, L

    2015-04-01

    Cutaneous adverse drug reactions (CADR) represent a heterogeneous field including various clinical patterns without specific features suggesting drug causality. Exanthematous eruptions, urticaria and vasculitis are the most common forms of CADR. Fixed eruption is uncommon in western countries. Serious reactions (fatal outcome, sequelae) represent 2% of CADR: bullous reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis), DRESS (drug reaction with eosinophilia and systemic symptoms or drug-induced hypersensitivity syndrome) and acute generalized exanthematous pustulosis (AGEP). These forms must be quickly diagnosed to guide their management. The main risk factors are immunosuppression, autoimmunity and some HLA alleles in bullous reactions and DRESS. Most systemic drugs may induce cutaneous adverse reactions, especially antibiotics, anticonvulsivants, antineoplastic drugs, non-steroidal anti-inflammatory drugs, allopurinol and contrast media. Pathogenesis includes immediate or delayed immunologic mechanism, usually not related to dose, and pharmacologic/toxic mechanism, commonly dose-dependent or time-dependent. In case of immunologic mechanism, allergologic exploration is possible to clarify drug causality, with a variable sensitivity according to the drug and to the CADR type. It includes epicutaneous patch testing, prick test and intradermal test. However, no in vivo or in vitro test can confirm the drug causality. To determine the cause of the eruption, a logical approach based on clinical characteristics, chronologic factors and elimination of differential diagnosis is required, completed with a literature search. A reporting to pharmacovigilance network is essential in case of a serious CADR whatever the suspected drug and in any case if the involved drug is a newly marketed one or unusually related to cutaneous reactions.

  12. Improved understanding of the loss-of-symmetry phenomenon in the conventional Kalman filter

    NASA Technical Reports Server (NTRS)

    Verhaegen, M. H.

    1989-01-01

    This paper corrects an unclear statement of the conventional Kalman filter implementation as presented by M. H. Verhaegen and P. van Dooren in Numerical aspects of different Kalman filter implementations, IEEE Trans. Automat. Contr., v. AC-31, no. 10, pp. 907-917, 1986. It is shown that the habitual, incorrect implementation of the Kalman filter has been the major cause of its insensitivity to the so-called loss-of-symmetry phenomenon.

  13. Synchrotron imaging and diffraction to investigate internal features of stable tearing fracture phenomenon in metallic specimens.

    PubMed

    Frink, Elizabeth; Lease, Kevin

    2012-07-01

    In situ synchrotron imaging and diffraction on beamline 1-ID-C at the Advanced Photon Source (APS) has been used to investigate the internal features present during the stable tearing fracture phenomenon in low-constraint metallic specimens. The results that are obtained from this investigation show that the internal features are identifiable with these techniques, and this initial investigation lays the groundwork for future, more in-depth investigations with some improvements to the methods.

  14. Oesophagitis dissecans superficialis: an acute, benign phenomenon associated with pemphigus vulgaris.

    PubMed

    Cesar, W G G; Barrios, M M; Maruta, C W; Aoki, V; Santi, G G

    2009-12-01

    Pemphigus vulgaris (PV) is an autoimmune dermatosis that may evolve to severely compromise the skin and/or mucosa. Autoantibodies directed against epithelial cadherins, such as desmogleins 1 and 3, lead to acantholysis and culminate in blister formation. Involvement of the oral mucosa is common, but other squamous stratified epithelia may also be the target of the autoimmune aggression. We report a woman with PV that was in partial remission, who developed an unusual acute phenomenon, known as oesophagitis dissecans superficialis.

  15. [The "off-on" phenomenon during treatment of parkinson's disease with levodopa (author's transl)].

    PubMed

    Wajsbort, J

    1977-04-28

    The fluctuation in daily performance of Parkinson patients on long-term L-dopa therapy is known as the so called "off-on" phenomenon. Cotzias et al. found that a low protein diet is able to control this phenomenon in patients taking L-dopa alone but not in those receiving a combination of L-dopa and decarboxylase inhibitor. The author's hypothesis was based on the competition between the alimentary aminoacids and L-dopa for transport to the brain ganglia. In our attempt to prove the findings of Cotzias group we tested the influence of a low protein diet on 23 Parkinson patients manifesting the "off-on" phenomenon. All had been pretreated with L-dopa for 5--8 years and taking dopa DI for a minimum of 3 years. The protein intake was limited to 25 g/day (which is less than 0.5 g/kg body weight) for 1--4 months. In 6 cases there was a marked improvment with reduction of the "off-on" effect, and in one it disappeared completely. A distinct improvment of general capability was seen in the other 5 cases, and an objective improvment of the symptoms was noted, except during the "off" period. No response could be observed in the remaining 12 cases. All cases with hyperkinesia showed an augmentation of this symptom during the use of the diet. The diet restriction was not found to be correlated with age, stage, duration of illness or duration of dopa treatment. The possible mechanism of the "off-on" phenomenon and some suggestions to influence it, are presented.

  16. Improved understanding of the loss-of-symmetry phenomenon in the conventional Kalman filter

    NASA Technical Reports Server (NTRS)

    Verhaegen, M. H.

    1987-01-01

    This paper corrects an unclear treatment of the conventional Kalman filter implementation as presented by M. H. Verhaegen and P. van Dooren in Numerical aspects of different Kalman filter implementations, IEEE Trans. Automat. Contr., v. AC-31, no. 10, pp. 907-917, 1986. It is shown that habitual, incorrect implementation of the Kalman filter has been the major cause of its sensitivity to the so-called loss-of-symmetry phenomenon.

  17. Rendering edge enhancement tactile phenomenon by friction variation in dynamic touch.

    PubMed

    Abdolvahab, Mohammad

    2011-01-04

    Variable friction tactile displays have been recently used to render virtual textures and gratings. Neural basis of perceptual mechanism of detection of edge-like features resulting in discrimination of virtual gratings during active touching these tactile actuators is studied using a finite-element biomechanical model of human fingertip. The predicted neural response of the mechanoreceptors, i.e. the computed strain energy density at the location of selected mechanoreceptors as a measure of neural discharge rate of the corresponding receptors, to local reduction of friction between fingerpad and surface are shown to exhibit a similar shape as the edge enhancement phenomenon, particularly in a sudden burst at the boundary of variable friction regions. This phenomenon is supposed to account for the illusion of virtual edges rendered through the modification of contact forces. The presence of this sudden burst under varied model parameters was investigated. It was shown that while the appearance of this phenomenon in simulation results was invariant to model parameters, associated alteration of the edge enhancement ratio might be considered for the purpose of the tuning of the variable friction tactile display.

  18. The challenges of choosing and explaining a phenomenon in epidemiological research on the "Hispanic Paradox".

    PubMed

    Valles, Sean A

    2016-04-01

    According to public health data, the US Hispanic population is far healthier than would be expected for a population with low socioeconomic status. Ever since Kyriakos Markides and Jeannine Coreil highlighted this in a seminal 1986 article, public health researchers have sought to explain the so-called "Hispanic paradox." Several candidate explanations have been offered over the years, but the debate goes on. This article offers a philosophical analysis that clarifies how two sets of obstacles make it particularly difficult to explain the Hispanic paradox. First, different research projects define the Hispanic paradox phenomenon in substantially different ways. Moreover, using Bas van Fraassen's pragmatic theory of explanation and Sean Valles's extension of it with the concept of "phenomenon choice," it also becomes clear that there are also multiple ways of explaining each individual definition of the phenomenon. A second set of philosophical and methodological challenges arises during any attempt to study "Hispanic" phenomena, with one key challenge being that the "Hispanic" panethnic concept was intentionally made vague as it was developed and popularized during the 1960s-1970s. After comparing this case with similar cases in the philosophical literature, the article concludes with observations on what makes this problem unique, particularly its ethical features.

  19. [Friends of virtual Ana--the phenomenon of pro-anorexia in the Internet].

    PubMed

    Stochel, Martyna; Janas-Kozik, Małgorzata

    2010-01-01

    Anorexia nervosa is regarded as a serious mental disturbance, where denial of illness and strong resistance to treatment are symptomatic features. In many cases it leads to extreme devastation or even to death. Effective treatment of this disorder still remains a challenge for clinicians and researchers. Since the 90-ies of the previous century there has been a rise in the free access to the internet. At present over a billion people all over the world use it. What young people look for in the internet is not only information, but also friends, support or entertainment. For last a few years, a phenomenon of pro-anorexia has been present in the Internet, connecting people who claim that anorexia is a "lifestyle" rather than a deadly illness, which should be treat. They communicate with each other through the internet blogs, forums and popular social networking sites, creating a virtual community. The pro-ana community is made up of adolescent girls and young women who decide on dieting. Pro-anorexia is still a poorly known phenomenon, especially in Poland. It seems to be very important to take a note on this phenomenon in the face of an increasing prevalence of eating disorders in the last years.

  20. The B[e] Phenomenon in Pre-Main-Sequence Herbig Ae/Be Stars

    NASA Astrophysics Data System (ADS)

    Oudmaijer, R. D.

    2017-02-01

    In this review I describe the intermediate mass pre-main-sequence Herbig Ae/Be stars and their role in studies of star formation. They play a particularly important part in understanding the differences between the accretion of matter onto low and high mass stars. Once these differences are understood, further progress can be made in high mass star formation. Given that the B[e] phenomenon is a spectroscopic one, I will present recent developments in the spectroscopic studies of the Herbig Ae/Be stars, and then move to the [e] phenomenon in these object. Based on a large sample, it is found that forbidden lines are present for half of the Herbig Ae/Be stars, implying that the "[e]" phenomenon is widespread in Herbig Ae/Be stars. I will describe how the presence and properties of these lines can be used to our advantage in learning about their circumstellar environments, and their disks in particular. I conclude with a forward look.

  1. Abnormalities of Bell's phenomenon in amyotrophic lateral sclerosis: a clinical and electrophysiological evaluation.

    PubMed Central

    Esteban, A; De Andrés, C; Giménez-Roldán, S

    1978-01-01

    A clinical and electromyographic study of oculomotor function was carried out in a series of 24 patients with amyotrophic lateral sclerosis (ALS). In 15 cases an alteration of Bell's phenomenon was found. In addition, three patients showed some impairment of conjugate ocular motility in the form of upward gaze paly. All cases had preserved oculocephalic reflexes in the vertical and horizontal planes. On clinical and electromyographic grounds, three degrees of altered Bell's phenomenon are suggested: attenuated (short and unsustained upward displacement of the eyeballs after forced closure of the eyelids), abolished (no upward displacement), and inverted (downward instead of upward displacement of the eyes). These oculomotor alterations were not directly related to the type of ALS at onset of the illness, nor with its duration. However they were correlated with the relative degree of the clinical bilateral pyramidal tract signs at the supraspinal level. The common involvement of the corticogeniculate tract in ALS could explain the unexpectedly high incidence of alteration of Bell's phenomenon found in this disease, but is is non-specific and similar lesions from different causes may also produce it. Images PMID:681956

  2. The influence of intraperitoneal transplantation of free and encapsulated Langerhans islets on the second set phenomenon.

    PubMed

    Orłowski, Tadeusz; Godlewska, Ewa; Mościcka, Maria; Sitarek, Elzbieta

    2003-12-01

    To protect the allografts or xenografts against transplant rejection special semipermeable membranes are applied. So far, there are only a few studies on the influence of an immunoisolated graft on the recipient immune system. Therefore, the possibility that an intraperitoneally grafted alginate/poly L-lysine/alginate (APA) coated pancreatic islets graft can effectively sensitize the recipient and provoke second set phenomenon was studied. C3H male mice and male WAG rats were used as donors of full-thickness skin and of free or encapsulated islet intraperitoneal grafts. Male BALB/c mice served as recipients. Skin grafts were performed following the method of Billingham and Medawar. The length of the second skin graft survival time served as the criterion for the sensitizing capacity of the primary graft. APA encapsulation of islets delayed but has not prevented the development of the second set phenomenon. However, the second skin graft rejection time was significantly longer after grafting of encapsulated islets than after free islets transplantation. APA microencapsulation of intraperitoneally transplanted islets delayed but did not prevent the development of the second set phenomenon. Encapsulation does not ensure complete immunoisolation, but only creates "an artificially immunoprivileged site of transplantation."

  3. Sperm conjugation in mammal reproductive function: Different names for the same phenomenon?

    PubMed

    Monclus, Maria Angeles; Fornes, Miguel Walter

    2016-10-01

    In many mammalian and non-mammalian species, mature sperm interact within the female reproductive tract or inside the epididymal lumen using cohesive forces. This phenomenon, known as "sperm conjugation," is sometimes confused with sperm agglutination, which is the result of the interaction of epididymal or ejaculate spermatozoa upon release into culture medium. In addition to "agglutination," the terms "association," "rouleaux," or "rosettes" are employed interchangeably to describe the conjugation phenomenon, which inevitably causes confusion due to the non-unifying nomenclature. This variety of descriptions is likely due to a poor understanding of the molecular mechanisms involved in such conspicuous cell-cell interaction as well as the different morphologies that result from such interactions among species. Here, we summarize the published data regarding mammalian sperm conjugation, considering the organisms in which sperm interaction was observed; the particular terminology employed; findings regarding the components that enable sperm to adhere; sperm behavior when deposited in the female reproductive tract; and hypotheses formulated to clarify the biological function and, when known, the mechanisms for sperm interaction. We also propose a new classification system for this phenomenon that might clearly unify the criteria used to describe this behavior. Mol. Reprod. Dev. 83: 884-896, 2016 © 2016 Wiley Periodicals, Inc.

  4. ["Placebo effect", from personal convictions to collective representations: A psychosocial reading of a pharmacodynamic phenomenon].

    PubMed

    Balez, R; Couturaud, F; Touffet, L

    2015-11-01

    After starting with a brief historical account of the placebo effect organized around the elaboration of clinical trials and around sham therapy as a method, we will offer a psychosocial point of view on the placebo phenomenon. The placebo effect is at the heart of medicine and particularly of therapeutic trials from theoretical research on a drug to its acceptance and its use in every-day clinical practice. The placebo effect intermingles biology, relationships and the context of therapeutic interactions. This type of phenomenon originates as much from biology as from human psychology. Our article puts more precisely into question the part that psychology has in the placebo phenomenon and suggests a chart to address it. This chart refers both to the pharmacodynamic effect given to drugs in a subjective way, and to the collective representations and social interactions depending on them. What can we say about the psychosociological dimensions of the placebo effect? How is it possible to organize the scope of these dimensions to base systematic studies on them in the field of clinical trials? We try to give elements of response to these questions by suggesting the study of the placebo effect as an original field of study by necessarily mobilizing both health sciences and the human and social sciences.

  5. Phenomenon analysis of stress corrosion cracking in the vessel head penetrations of French PWR`s

    SciTech Connect

    Pichon, C.; Buisine, D.; Faidy, C.; Gelpi, A.; Vaindirlis, M.

    1995-12-31

    During a hydrotest in 1991, a leak was detected on,a reactor vessel head (RVH) penetration of a French PWR. This leak was due to a phenomenon of Primary Water Stress Corrosion Cracking (PWSCC) affecting these penetrations in Alloy 600. The destructive and non-destructive examinations undertaken during the following months highlighted the generic nature of the degradations. In order to well understand this phenomenon and implement the most suitable maintenance policy, a large scale scientific program was decided and performed jointly by Electricite de France and FRAMATOME. The paper will present all the results obtained in this program concerning the parameters governing the PWSCC. In particular the following fields will be developed: (1) the material, its microstructure in line with the manufacturing and its susceptibility to PWSCC; (2) the stresses and their evaluations by measurements, mock up corrosion tests and Finite Element Analysis (FEA); (3) the effect of surface finish on crack initiation; and (4) the crack growth rate. This phenomenon analysis will be useful for evaluating the risk of PWSCC on other Alloy 600 areas in PWR`s primary system.

  6. Chasing spirits: Clarifying the spirit child phenomenon and infanticide in Northern Ghana.

    PubMed

    Denham, Aaron R; Adongo, Philip B; Freydberg, Nicole; Hodgson, Abraham

    2010-08-01

    In the Kassena-Nankana District of Ghana, researchers and health interventionists describe a phenomenon wherein some children are subject to infanticide because they are regarded as spirit children sent "from the bush" to cause misfortune and destroy the family. This phenomenon remains largely misunderstood and misrepresented. Based upon both ethnographic research and verbal autopsy data from 2006 to 2007 and 2009, this paper clarifies the characteristics of and circumstances surrounding the spirit child phenomenon, the role it plays within community understandings of childhood illness and mortality, and the variations present within the discourse and practice. The spirit child is a complex explanatory model closely connected to the Nankani sociocultural world and understandings surrounding causes of illness, disability, and misfortune, and is best understood within the context of the larger economic, social, and health concerns within the region. The identification of a child as a spirit child does not necessarily indicate that the child was a victim of infanticide. The spirit child best describes why a child died, rather than how the death occurred. In addition to shaping maternal and child health interventions, these findings have implications for verbal autopsy assessments and the accuracy of demographic data concerning the causes of child mortality.

  7. Multiscale stochastic simulations of chemical reactions with regulated scale separation

    NASA Astrophysics Data System (ADS)

    Koumoutsakos, Petros; Feigelman, Justin

    2013-07-01

    We present a coupling of multiscale frameworks with accelerated stochastic simulation algorithms for systems of chemical reactions with disparate propensities. The algorithms regulate the propensities of the fast and slow reactions of the system, using alternating micro and macro sub-steps simulated with accelerated algorithms such as τ and R-leaping. The proposed algorithms are shown to provide significant speedups in simulations of stiff systems of chemical reactions with a trade-off in accuracy as controlled by a regulating parameter. More importantly, the error of the methods exhibits a cutoff phenomenon that allows for optimal parameter choices. Numerical experiments demonstrate that hybrid algorithms involving accelerated stochastic simulations can be, in certain cases, more accurate while faster, than their corresponding stochastic simulation algorithm counterparts.

  8. Reaction/Momentum Wheel

    NASA Technical Reports Server (NTRS)

    1997-01-01

    CTA Space Systems, Inc. has been licensed to sell commercially a reaction/momentum wheel originally developed for NASA's scientific satellites. NASA originally identified a need for the wheel in its Small Explorer program. The Submillimeter Wave Astronomy Satellite required extremely low jitter and a reaction/momentum wheel with a torque greater than any comparably sized commercially available wheel to keep the instrument pointed at celestial objects to a high degree of precision. After development, a market assessment by Research Triangle Institute was completed, showing commercial potential for the flywheel technology. A license was granted to CTA in the fall of 1996. The company currently uses the technology in its complete spacecraft fabrication services and has built over 10 reaction/momentum wheels for commercial, scientific, and military customers.

  9. Velocity pump reaction turbine

    DOEpatents

    House, Palmer A.

    1984-01-01

    An expanding hydraulic/two-phase velocity pump reaction turbine including a dual concentric rotor configuration with an inter-rotor annular flow channel in which the inner rotor is mechanically driven by the outer rotor. In another embodiment, the inner rotor is immobilized and provided with gas recovery ports on its outer surface by means of which gas in solution may be recovered. This velocity pump reaction turbine configuration is capable of potential energy conversion efficiencies of up to 70%, and is particularly suited for geothermal applications.

  10. Velocity pump reaction turbine

    DOEpatents

    House, Palmer A.

    1982-01-01

    An expanding hydraulic/two-phase velocity pump reaction turbine including a dual concentric rotor configuration with an inter-rotor annular flow channel in which the inner rotor is mechanically driven by the outer rotor. In another embodiment, the inner rotor is immobilized and provided with gas recovery ports on its outer surface by means of which gas in solution may be recovered. This velocity pump reaction turbine configuration is capable of potential energy conversion efficiencies of up to 70%, and is particularly suited for geothermal applications.

  11. Velocity pump reaction turbine

    SciTech Connect

    House, P.A.

    1984-02-07

    An expanding hydraulic/two-phase velocity pump reaction turbine including a dual concentric rotor configuration with an inter-rotor annular flow channel in which the inner rotor is mechanically driven by the outer rotor. In another embodiment, the inner rotor is immobilized and provided with gas recovery ports on its outer surface by means of which gas in solution may be recovered. This velocity pump reaction turbine configuration is capable of potential energy conversion efficiencies of up to 70%, and is particularly suited for geothermal applications.

  12. Velocity pump reaction turbine

    SciTech Connect

    House, P.A.

    1982-06-01

    An expanding hydraulic/two-phase velocity pump reaction turbine including a dual concentric rotor configuration with an interrotor annular flow channel in which the inner rotor is mechanically driven by the outer rotor. In another embodiment, the inner rotor is immobilized and provided with gas recovery ports on its outer surface by means of which gas in solution may be recovered. This velocity pump reaction turbine configuration is capable of potential energy conversion efficiencies of up to 70%, and is particularly suited for geothermal application

  13. Velocity pump reaction turbine

    DOEpatents

    House, P.A.

    An expanding hydraulic/two-phase velocity pump reaction turbine including a dual concentric rotor configuration with an inter-rotor annular flow channel in which the inner rotor is mechanically driven by the outer rotor. In another embodiment, the inner rotor is immobilized and provided with gas recovery ports on its outer surface by means of which gas in solution may be recovered. This velocity pump reaction turbine configuration is capable of potential energy conversion efficiencies of up to 70%, and is particularly suited for geothermal applications.

  14. Does the Teacher's Pet Phenomenon Inevitably Cause Classroom Conflict? Comparative Viewpoints of Three Pet-Student Groups

    ERIC Educational Resources Information Center

    Chiu, Shao-I; Lee, Jiezhi; Liang, Tsanglang

    2013-01-01

    Although most studies reveal a relationship between the teacher's pet phenomenon with classroom conflict, it does not necessarily cause classroom conflict. This study confirms the model fit for teacher authority, the existence of the teacher's pet phenomenon and its relationship to classroom conflict and students' self-adjustment, as well as…

  15. The Market Phenomenon in Taiwanese Junior High Level Education: Behind the Battles between Streaming and Mixed-Ability Grouping

    ERIC Educational Resources Information Center

    Lu, Ling-Ying

    2012-01-01

    In this article, the author explores the market phenomenon revealed in the practice of a mixed-ability grouping policy in Taiwan, and traces the influence of the wider educational contexts on the formation of the market phenomenon. Although there have been no major policies introduced with the intention of creating a market mechanism in Taiwanese…

  16. Phenomenon of organic carbon change in natural waters (system "catchment - Lake") of Russian Federation

    NASA Astrophysics Data System (ADS)

    Dinu, Marina; Tatyana, Moiseenko; Tatyana, Kremleva; Natalia, Gashkina

    2015-04-01

    this phenomenon. The water color is predominantly determined by large molecules of humus acids which molecular weight >1000 Da. Macromolecular organic substances of humus type can be dissociated in water with formation of a free proton, as well as enter into reactions of decomposition (hydrolysis) and disproportionation with formation of low-molecular weight fragments. Its fragments also are dissociated of proton (see the diagram below). Non-organic strong acids supplied from anthropogenic and natural sources may catalyze the above processes. The diagram of the organic substances destruction of humus origin is given below, where Ri means non-symmetrical fragments of a natural polymer, X_iH - functional groups of organic substances of humus origin, and n - number of protons. begin{equation*} HX_1-R_1-R_2-X_2H begin{array}{l} → R_1-X_1H + R_2-X_2H quad + quad R{^'}{_1} X1^- + R{^'}{_2} X2^- + nH+ → HX_1-R_1-R2 X_2- + - X_1R_1-R_2-X_2H + - X_1R_1-R2 X_2- + nH+ end{equation*} When strong acids get into a water environment humus acids are degraded into fractions. It could be supposed that the organic matter structure undergoes changes in natural waters, as the fraction of high-molecular weight humus acids decrease. As a consequence of interaction between humus substances and protons the humic acids precipitate to form bottom sediments, whereas fulvic acids remain in water. Fulvic acids are characterized by lower molecular weights (from 500 to 2000 Da) and exert an insignificant effect on the water color. Skelkvale, B.L., J.L. Stoddard, D.S. Jeffries, K. Torseth, T. Hogasen, J. Bowman, L. Mannio, Monteith, D.T., et al. 2005. Regional scale evidence for improvements in surface water chemistry 1990-2001. Environmental Pollution 137(1): 165-176. Moiseenko, T., L. Kudrjavzeva, I. Rodyshkin. 2001. The episodic acidification of small streams in the spring flood period of industrial polar region, Russia. Chemosphere 362: 45-50.

  17. On the cause of the flat-spot phenomenon observed in silicon solar cells at low temperatures and low intensities. [in deep space environments

    NASA Technical Reports Server (NTRS)

    Weizer, V. G.; Broder, J. D.

    1982-01-01

    A model is presented that explains the 'flat-spot' power-loss phenomenon observed in silicon solar cells operating under deep space (low temperature, low intensity) conditions. Evidence is presented suggesting that the effect is due to localized metallurgical interactions between the silicon substrate and the contact metallization. These reactions are shown to result in localized regions in which the PN junction is destroyed and replaced with a metal-semiconductor-like interface. The effects of thermal treatment, crystallographic orientation, junction depth, and metallization are presented along with a method of preventing the effect through the suppression of vacancy formation at the free surface of the contact metallization. Preliminary data indicating the effectiveness of a TiN diffusion barrier in preventing the effect are also given.

  18. Reaction product imaging

    SciTech Connect

    Chandler, D.W.

    1993-12-01

    Over the past few years the author has investigated the photochemistry of small molecules using the photofragment imaging technique. Bond energies, spectroscopy of radicals, dissociation dynamics and branching ratios are examples of information obtained by this technique. Along with extending the technique to the study of bimolecular reactions, efforts to make the technique as quantitative as possible have been the focus of the research effort. To this end, the author has measured the bond energy of the C-H bond in acetylene, branching ratios in the dissociation of HI, the energetics of CH{sub 3}Br, CD{sub 3}Br, C{sub 2}H{sub 5}Br and C{sub 2}H{sub 5}OBr dissociation, and the alignment of the CD{sub 3} fragment from CD{sub 3}I photolysis. In an effort to extend the technique to bimolecular reactions the author has studied the reaction of H with HI and the isotopic exchange reaction between H and D{sub 2}.

  19. Introducing the Wittig Reaction.

    ERIC Educational Resources Information Center

    Armstead, D. E. F.

    1979-01-01

    An experiment is described which provides a simple example of the application of the Wittig reaction to the synthesis of unsaturated compounds. The experiment was designed with British HNC chemistry students in mind, but it is also suitable as a project-type exercise for final year GCE A-level students. (Author/BB)

  20. Enantioselective Vinylogous Organocascade Reactions.

    PubMed

    Hepburn, Hamish B; Dell'Amico, Luca; Melchiorre, Paolo

    2016-08-01

    Cascade reactions are powerful tools for rapidly assembling complex molecular architectures from readily available starting materials in a single synthetic operation. Their marriage with asymmetric organocatalysis has led to the development of novel techniques, which are now recognized as reliable strategies for the one-pot enantioselective synthesis of stereochemically dense molecules. In recent years, even more complex synthetic challenges have been addressed by applying the principle of vinylogy to the realm of organocascade catalysis. The key to the success of vinylogous organocascade reactions is the unique ability of the chiral organocatalyst to transfer reactivity to a distal position without losing control on the stereo-determining events. This approach has greatly expanded the synthetic horizons of the field by providing the possibility of forging multiple stereocenters in remote positions from the catalyst's point of action with high selectivity, while simultaneously constructing multiple new bonds. This article critically describes the developments achieved in the field of enantioselective vinylogous organocascade reactions, charting the ideas, the conceptual advances, and the milestone reactions that have been essential for reaching highly practical levels of synthetic efficiency.

  1. Chain Reaction Polymerization.

    ERIC Educational Resources Information Center

    McGrath, James E.

    1981-01-01

    The salient features and importance of chain-reaction polymerization are discussed, including such topics as the thermodynamics of polymerization, free-radical polymerization kinetics, radical polymerization processes, copolymers, and free-radical chain, anionic, cationic, coordination, and ring-opening polymerizations. (JN)

  2. Chemical Reactions at Surfaces

    SciTech Connect

    Michael Henderson and Nancy Ryan Gray

    2010-04-14

    Chemical reactions at surfaces underlie some of the most important processes of today, including catalysis, energy conversion, microelectronics, human health and the environment. Understanding surface chemical reactions at a fundamental level is at the core of the field of surface science. The Gordon Research Conference on Chemical Reactions at Surfaces is one of the premiere meetings in the field. The program this year will cover a broad range of topics, including heterogeneous catalysis and surface chemistry, surfaces in environmental chemistry and energy conversion, reactions at the liquid-solid and liquid-gas interface, electronic materials growth and surface modification, biological interfaces, and electrons and photons at surfaces. An exciting program is planned, with contributions from outstanding speakers and discussion leaders from the international scientific community. The conference provides a dynamic environment with ample time for discussion and interaction. Attendees are encouraged to present posters; the poster sessions are historically well attended and stimulate additional discussions. The conference provides an excellent opportunity for junior researchers (e.g. graduate students or postdocs) to present their work and interact with established leaders in the field.

  3. Reaction Formulation: A Bibliography.

    ERIC Educational Resources Information Center

    Pedrini, D. T.; Pedrini, Bonnie C.

    Reaction formation was studied by Sigmund Freud. This defense mechanism may be related to repression, substitution, reversal, and compensation (or over-compensation). Alfred Adler considered compensation a basic process in his individual psychology. Anna Freud discussed some defense mechanisms, and Bibring, Dwyer, Huntington, and Valenstein…

  4. Lithium Cell Reactions.

    DTIC Science & Technology

    1985-02-01

    Page 1. INVESTIGATION OF CHEMICAL, ELECTROCHEMICAL AND PARASITIC REACTIONS IN LITHIUM - THIONYL CHLORIDE CELLS ....... ................. 1 1.1 INTRODUCTION...OF LITHIUM - THIONYL CHLORIDE CELLS. ................ 56 1.4.1 Carbon Limited Overdischarge...............56 1.4.1.1 Background... LITHIUM THIONYL - CHLORIDE CELLS. .. ............ ...... 101 1.5.1 Background. ....... ............ .... 101 1.5.2 Microphotography

  5. Confronting Combat Stress Reactions

    DTIC Science & Technology

    2010-03-22

    of the scalp, skull , or brain. 4 Combat stress reaction is categorized as a range of behaviors resulting from the stress of battle which decreases...3) experiencing rage aimed at discriminate and indiscriminate targets, (4) psychic numbing or emotional shutdown, (5) alienation from themselves and

  6. A Superintendent's Reaction

    ERIC Educational Resources Information Center

    Lytle, James H.

    2004-01-01

    This article presents a superintendent's reaction to Catherine Marshall and Michael Ward's article on research on social justice and training for leadership. The author states that there is a problem with Marshall and Ward's article which begins with the title, particularly with the word "training." The author contends that there is a significant…

  7. Polymerase chain reaction system

    DOEpatents

    Benett, William J.; Richards, James B.; Stratton, Paul L.; Hadley, Dean R.; Milanovich, Fred P.; Belgrader, Phil; Meyer, Peter L.

    2004-03-02

    A portable polymerase chain reaction DNA amplification and detection system includes one or more chamber modules. Each module supports a duplex assay of a biological sample. Each module has two parallel interrogation ports with a linear optical system. The system is capable of being handheld.

  8. Exocharmic Reactions up Close

    ERIC Educational Resources Information Center

    Ramette, R. W.

    2007-01-01

    The exocharmic reactions that can be observed microscopically are discussed. The students can discover the optimal concentration of an acidic lead nitrate solution, so that a crystal of potassium iodide, nudged to the edge of a drop, results in glinting golden hexagons of lead iodide.

  9. Three Reaction Papers.

    ERIC Educational Resources Information Center

    Coop, Richard H.; And Others

    1982-01-01

    In reaction papers, Richard H. Coop, an educational psychologist, discusses six themes evident in papers on gifted education; B. J. Cox argues that systems theory is a valuable addition to education of identified and potentially gifted students; and Gary D. Fenstermacher argues for specification of educational entitlements of any learner before…

  10. The aromatic ene reaction

    PubMed Central

    Niu, Dawen; Hoye, Thomas R.

    2014-01-01

    The ene reaction is a pericyclic process in which an alkene having an allylic hydrogen atom (the ene donor) reacts with a second unsaturated species (the enophile) to form a new product with a transposed π-bond. The aromatic ene reaction, in which the alkene component is embedded in an aromatic ring, has only been reported in a few (four) instances and has proceeded in low yield (≤6%). Here we show efficient aromatic ene reactions in which a thermally generated aryne engages a pendant m-alkylarene substituent to produce a dearomatized isotoluene, itself another versatile but rare reactive intermediate. Our experiments were guided by computational studies that revealed structural features conducive to the aromatic ene process. We proceeded to identify a cascade comprising three reactions: (i) hexadehydro-Diels-Alder (for aryne generation), (ii) intramolecular aromatic ene, and (iii) bimolecular Alder ene. The power of this cascade is evident from the structural complexity of the final products, the considerable scope, and the overall efficiency of these multi-stage, reagent- and byproduct-free, single-pot transformations. PMID:24345944

  11. Reaction-Diffusion Patterns in Structured Media

    NASA Astrophysics Data System (ADS)

    Epstein, Irving

    I will look at pattern formation in the Belousov-Zhabotinsky (BZ) oscillating chemical reaction in media that are structured at length scales ranging from ten nanometers to a few centimeters. A reverse microemulsion consisting of nanometer diameter droplets of water containing the reactants dispersed in oil allows the physical structure (size, spacing) of the droplets and their chemical composition to be controlled independently, enabling one to generate a remarkable variety of stationary and moving patterns, including Turing structures, ordinary and antispirals, packet waves and spatiotemporal chaos. One- and two-dimensional arrays of aqueous droplets in oil generated by microfluidic techniques have diameters of the order of 100 micrometers and produce a different array of patterns that can be precisely controlled with light. In particular, circular arrays of droplets provide a testing ground for some of Turing's ideas about morphogenesis. By attaching the BZ catalyst to a polymer that shrinks and swells in response to changes in the redox state of the catalyst, one can construct gel materials that transduce chemical changes to mechanical motion, a phenomenon modeled with considerable success by the Balazs group. If time permits, I will also discuss the BZ reaction in coupled macroscopic flow reactors that mimic small neural networks.

  12. Chemical memory reactions induced bursting dynamics in gene expression.

    PubMed

    Tian, Tianhai

    2013-01-01

    Memory is a ubiquitous phenomenon in biological systems in which the present system state is not entirely determined by the current conditions but also depends on the time evolutionary path of the system. Specifically, many memorial phenomena are characterized by chemical memory reactions that may fire under particular system conditions. These conditional chemical reactions contradict to the extant stochastic approaches for modeling chemical kinetics and have increasingly posed significant challenges to mathematical modeling and computer simulation. To tackle the challenge, I proposed a novel theory consisting of the memory chemical master equations and memory stochastic simulation algorithm. A stochastic model for single-gene expression was proposed to illustrate the key function of memory reactions in inducing bursting dynamics of gene expression that has been observed in experiments recently. The importance of memory reactions has been further validated by the stochastic model of the p53-MDM2 core module. Simulations showed that memory reactions is a major mechanism for realizing both sustained oscillations of p53 protein numbers in single cells and damped oscillations over a population of cells. These successful applications of the memory modeling framework suggested that this innovative theory is an effective and powerful tool to study memory process and conditional chemical reactions in a wide range of complex biological systems.

  13. Effects of reaction time variability and age on brain activity during Stroop task performance.

    PubMed

    Tam, Angela; Luedke, Angela C; Walsh, Jeremy J; Fernandez-Ruiz, Juan; Garcia, Angeles

    2015-09-01

    Variability in reaction time during task performance may reflect fluctuations in attention and cause reduced performance in goal-directed tasks, yet it is unclear whether the mechanisms behind this phenomenon change with age. Using fMRI, we tested young and cognitively healthy older adults with the Stroop task to determine whether aging affects the neural mechanisms underlying intra-individual reaction time variability. We found significant between-group differences in BOLD activity modulated by reaction time. In older adults, longer reaction times were associated with greater activity in frontoparietal attentional areas, while in younger adults longer reaction times were associated with greater activity in default mode network areas. Our results suggest that the neural correlates of reaction time variability change with healthy aging, reinforcing the concept of functional plasticity to maintain high cognitive function throughout the lifespan.

  14. Triggering essential head tremor with sustained phonation: a clinical phenomenon with potential diagnostic value.

    PubMed

    Wright, Brenton A; Michalec, Monika; Louis, Elan D

    2014-02-01

    Here we report a clinical phenomenon that we have observed repeatedly in clinical research settings; namely, a triggering and/or exacerbation of head tremor during or immediately following sustained phonation. To our knowledge, it has not been reported previously nor has it been the subject of study. Here we: 1) report the phenomenon, 2) provide several visual illustrations, 3) estimate its prevalence, and 4) analyze its clinical correlates. Head tremor was assessed qualitatively, and scores were assigned pre-, during, and post-sustained phonation using the Tremor Research Group Essential Tremor Rating Assessment Scale. Seventy (68.6%) of 102 essential tremor (ET) patients exhibited a qualitative increase in head tremor amplitude during and/or immediately after sustained phonation; in 5 (4.9%), head tremor would not have been detected without the voice activation maneuver (i.e., it was not visible at any other point in the videotape aside from the period during/immediately following sustained phonation). Women were more likely than men to exhibit this phenomenon (p = 0.05), whereas age, age at onset, duration of tremor, and total tremor score did not predict responsiveness of head tremor to sustained phonation. Sustained voice activation is a useful examination maneuver that may elicit or amplify head tremor in ET. Head tremor is not reported to occur in patients with enhanced physiological tremor. Thus, this maneuver, by triggering head tremor, may be a useful diagnostic supplement, particularly in research/clinical settings where arm tremor is mild and the diagnosis (mild ET vs. enhanced physiological tremor) would otherwise be ambiguous.

  15. Investigation Results on Solar Array Thermal & Electrical Imbalance Phenomenon on Power Systems Equipped with MPPT

    NASA Astrophysics Data System (ADS)

    Mercier, F.; Samaniego, B.; Soriano, T.; Beaufils, G.; Fernandez Lisbona, E.; Dettlaff, K.; Jensen, H.

    2014-08-01

    The thermal / electrical imbalance phenomenon on the satellite solar arrays is a common issue inherent to the negative thermal voltage coefficient of the triple junction cells, which is usually already taken into account with basic precautions on the solar panel layout.In the frame of the ESA TRP study "Investigation on Solar Array thermal and electrical imbalance phenomenon on power systems equipped with Maximum Power Point Tracker (MPPT)" performed by Airbus Defence & Space (former Astrium Toulouse and Ottobrunn) and TERMA, in-depth analyses were conducted for the first time to better understand and characterize the secondary maximum power point phenomenon for various representative mission cases, whether in Earth vicinity or not. With the help of a newly developed detailed thermo-electrical coupled solver and a wide range of solar cell characterizations in flux and temperature, multiple sets of simulations were run to simulate realistic solar panel characteristics.The study showed that no secondary false maximum power point can be created on the solar panel characteristic IV curve for missions around Earth vicinity, at the sole exception of critical shadowing cases. Furthermore, the same conclusions apply for missions up to Mars orbit. The only potential threats come from the missions further than Mars (typically Jupiter missions) where various very high heterogeneities could lead to multiple maxima. This is deeply linked to the LILT (low illumination low temperature) conditions applied to the current solar cell triple junction characteristics and shape. Moreover, thermo-electrical imbalances that do not create secondary power point can still seriously grieve the solar array power output performances. This power loss can however be accurately assessed by the newly developed solver in support of in-development missions like Juice.

  16. Analysis of a Transonic Alternating Flow Phenomenon Observed During Ares Crew Launch Vehicle Wind Tunnel Tests

    NASA Technical Reports Server (NTRS)

    Sekula, Martin K.; Piatak, David J.; Rausch, Russ D.

    2010-01-01

    A transonic wind tunnel test of the Ares I-X Rigid Buffet Model (RBM) identified a Mach number regime where unusually large buffet loads are present. A subsequent investigation identified the cause of these loads to be an alternating flow phenomenon at the Crew Module-Service Module junction. The conical design of the Ares I-X Crew Module and the cylindrical design of the Service Module exposes the vehicle to unsteady pressure loads due to the sudden transition from separated to attached flow about the cone-cylinder junction with increasing Mach number. For locally transonic conditions at this junction, the flow randomly fluctuates back and forth between a subsonic separated flow and a supersonic attached flow. These fluctuations produce a square-wave like pattern in the pressure time histories which, upon integration result in large amplitude, impulsive buffet loads. Subsequent testing of the Ares I RBM found much lower buffet loads since the evolved Ares I design includes an ogive fairing that covers the Crew Module-Service Module junction, thereby making the vehicle less susceptible to the onset of alternating flow. An analysis of the alternating flow separation and attachment phenomenon indicates that the phenomenon is most severe at low angles of attack and exacerbated by the presence of vehicle protuberances. A launch vehicle may experience either a single or, at most, a few impulsive loads since it is constantly accelerating during ascent rather than dwelling at constant flow conditions in a wind tunnel. A comparison of a wind-tunnel-test-data-derived impulsive load to flight-test-data-derived load indicates a significant over-prediction in the magnitude and duration of the buffet load

  17. Toward Understanding the B[e] Phenomenon. II. New Galactic FS CMa Stars

    NASA Astrophysics Data System (ADS)

    Miroshnichenko, A. S.; Manset, N.; Kusakin, A. V.; Chentsov, E. L.; Klochkova, V. G.; Zharikov, S. V.; Gray, R. O.; Grankin, K. N.; Gandet, T. L.; Bjorkman, K. S.; Rudy, R. J.; Lynch, D. K.; Venturini, C. C.; Mazuk, S.; Puetter, R. C.; Perry, R. B.; Levato, H.; Grosso, M.; Bernabei, S.; Polcaro, V. F.; Viotti, R. F.; Norci, L.; Kuratov, K. S.

    2007-12-01

    FS CMa stars form a group of objects with the B[e] phenomenon that were previously known as unclassified B[e] stars or B[e] stars with warm dust (B[e]WD) until recently. They exhibit strong emission-line spectra and strong IR excesses, most likely due to recently formed circumstellar dust. These properties have been suggested to be due to ongoing or recent rapid mass exchange in binary systems with hot primaries and various types of secondaries. The first paper of this series reported an analysis of the available information about previously known Galactic objects with the B[e] phenomenon, the initial selection of the FS CMa group objects, and a qualitative explanation of their properties. This paper reports the results of our new search for more FS CMa objects in the IRAS Point Source Catalog. We present new photometric criteria for identifying FS CMa stars as well as the first results of our observations of nine new FS CMa group members. With this addition, the FS CMa group has now 40 members, becoming the largest among the dust-forming hot star groups. We also present nine objects with no evidence for the B[e] phenomenon, but with newly discovered spectral line emission and/or strong IR excesses. Partially based on data obtained at the 6 m BTA Telescope of the Russian Academy of Sciences, 3.6 m Canada-France-Hawaii Telescope, 3 m Shane Telescope of the Lick Observatory, 2.7 m Harlan J. Smith and 2.1 m Otto Struve Telescopes of the McDonald Observatory, 2.1 m telescope of the San Pedro Martir Observatory, 1.5 m telescope of the Loiano Observatory, and 0.8 m telescope of the Dark Sky Observatory.

  18. New objects with the B[e] phenomenon in the Large Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Levato, H.; Miroshnichenko, A. S.; Saffe, C.

    2014-08-01

    Aims: The study is aimed at discovering new objects with the B[e] phenomenon in the Large Magellanic Cloud. Methods: We report medium-resolution optical spectroscopic observations of two newly found (ARDB 54 and NOMAD 0181-0125572) and two previously known (Hen S-59 and Hen S-137) supergiants with the B[e] phenomenon in the Large Magellanic Cloud. The observations were obtained with the GMOS spectrograph at the southern Gemini telescope. Results: The optical spectra and the fundamental parameters of ARDB 54 and NOMAD 0181-0125572 are presented for the first time. We found that the Balmer line profiles of Hen S-59 and Hen S-137 were different from those observed in their spectra nearly 20 years ago. We suggest a higher effective temperature and luminosity for both objects. With the new fundamental parameters, the lowest luminosity for known supergiants with the B[e] phenomenon in the Magellanic Clouds is higher that previously thought (log L/L⊙ ~ 4.5 instead of 4.0). The object Hen S-59 may be a binary system based on its UV excess, variable B - V color-index and radial velocity of emission lines, and periodically variable I-band brightness. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência, Tecnologia e Inovacão (Brazil) and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).

  19. Epiretinal Proliferation Associated with Macular Hole and Intraoperative Perifoveal Crown Phenomenon

    PubMed Central

    Son, Gisung; Lee, Ji Shin; Lee, Suchan

    2016-01-01

    Purpose To discuss the unique morphology and origin of epiretinal proliferation associated with macular hole (EPMH) occasionally observed in full-thickness macular hole (FT-MH) or lamellar hole (LH) and to introduce the perifoveal crown phenomenon encountered when removing this unusual proliferative tissue. Methods Sixteen patients showing EPMH in spectral domain-optical coherence tomography were selected from 212 patients diagnosed with MH, LH, FT-MH, impending MH, macular pseudohole, or epiretinal membrane between January 2013 and December 2014. Of the 212 patients included for clinical analysis, 33, 23, 11, 7, and 190 exhibited LH, FT-MH, impending MH, macular pseudohole, and epiretinal membrane, respectively. We reviewed visual acuity, macular morphology, and clinical course. Surgical specimens were analyzed histologically. Results EPMH presented as an amorphous proliferation starting from the defective inner/outer segment (IS/OS) junction covering the inner macula surface. Among the 16 patients with EPMH, 11 underwent vitrectomy, and all exhibited the intraoperative perifoveal crown phenomenon. EPMH tissue was sampled in three patients, one of whom had more tissue removed than intended and showed delayed recovery in visual acuity. Despite hole closure, IS/OS junction integrity was not successfully restored in four of 11 patients. Five patients were followed-up without surgical intervention. Visual acuity slightly decreased in three patients and did not change in one patient, while the remaining patient was lost during follow-up. Among the three perifoveal crown tissues obtained, two were successfully analyzed histologically. Neither tissue showed positivity to synaptophysin or S-100 protein, but one showed positivity to cytokeratin protein immunohistochemical staining. Conclusions EPMH exhibited a distinct but common configuration in spectral domain-optical coherence tomography. An epithelial proliferation origin is plausible based on its configuration and

  20. Inorganic Reaction Mechanisms. Part I

    ERIC Educational Resources Information Center

    Cooke, D. O.

    1976-01-01

    Provides a collection of data on the mechanistic aspects of inorganic chemical reactions. Wherever possible includes procedures for classroom demonstration or student project work. The material covered includes gas phase reactions, reactions in solution, mechanisms of electron transfer, the reaction between iron III and iodine, and hydrolysis. (GS)