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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. User`s input manual for quasi-steady sodium/water reaction analysis computer program SWAC-13E

    SciTech Connect

    Shin, Y W; Choi, U S; Nelson, S O

    1985-08-01

    SWAC-13E is a quasi-steady two-phase flow analysis code for liquid sodium and hydrogen mixtures in an LMFBR intermediate heat transport system and pressure relief system following large-leak sodium/water reactions in a steam generator. SWAC-13E complements the SWAAM-II and SWAAM-LT codes developed by ANL. SWAC-13E was received from Power Reactor and Nuclear Fuel Development Corporation (PNC) of Japan through an international agreement on the exchange of breeder reactor technology between the US Department of Energy and PNC. SWAC-13E was originally written for the Japanese computer system FACOM, and was converted to run on an IBM system at ANL. Input data needed for execution of the SWAC-13E code are described, following the understanding gained through execution of the code for several example problems. The coding changes involved in the conversion are also described. This report is intended to serve as the first document for use of the IBM version of SWAC-13E. Users are referred to various other documents for details of the code capabilities, theoretical basis, and other pertinent information needed in use of the code.

  4. 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.

  5. 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.

  6. 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.

  7. Lepra Reaction with Lucio Phenomenon Mimicking Cutaneous Vasculitis

    PubMed Central

    Misra, Durga Prasanna; Parida, Jyoti Ranjan; Chowdhury, Abhra Chandra; Pani, Krushna Chandra; Kumari, Niraj; Krishnani, Narendra

    2014-01-01

    Leprosy is a disease typically found in the tropics. Patients with leprosy can have varying presentation with constitutional symptoms, joint pains, skin nodules, and rarely a vasculitis-like picture with skin ulcers and neuropathy. We present a young lady who presented with the rare manifestation of skin infarcts mimicking cutaneous vasculitis, diagnosed on histopathology to have Lucio phenomenon on a background of lepromatous leprosy. With increasing migration and widespread use of biologic response modifiers, clinicians all over the world need to be aware of various presentations of leprosy as well as needing to keep an open mind while considering the differential diagnoses of vasculitis. PMID:25580317

  8. Lepra reaction with lucio phenomenon mimicking cutaneous vasculitis.

    PubMed

    Misra, Durga Prasanna; Parida, Jyoti Ranjan; Chowdhury, Abhra Chandra; Pani, Krushna Chandra; Kumari, Niraj; Krishnani, Narendra; Agarwal, Vikas

    2014-01-01

    Leprosy is a disease typically found in the tropics. Patients with leprosy can have varying presentation with constitutional symptoms, joint pains, skin nodules, and rarely a vasculitis-like picture with skin ulcers and neuropathy. We present a young lady who presented with the rare manifestation of skin infarcts mimicking cutaneous vasculitis, diagnosed on histopathology to have Lucio phenomenon on a background of lepromatous leprosy. With increasing migration and widespread use of biologic response modifiers, clinicians all over the world need to be aware of various presentations of leprosy as well as needing to keep an open mind while considering the differential diagnoses of vasculitis.

  9. 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

  10. Tournay's description of anisocoria on lateral gaze: reaction, myth, or phenomenon?

    PubMed

    Robert, Matthieu P; Plant, Gordon T

    2014-02-04

    The year 1917 witnessed the opening of a great debate in neuro-ophthalmology, with Tournay's description of a phenomenon thought to be universal: anisocoria in lateral gaze, due to mydriasis of the abducting pupil and a minor miosis of the fellow one. Through many publications, this phenomenon was soon assessed and confirmed to be physiologic, while the cause of the pupil reaction in lateral gaze was extensively discussed. Cases of abolition and reversal of the phenomenon were also reported in specific clinical situations, such as neurosyphilis, and its study became part of the neuro-ophthalmologic examination. Publications on the phenomenon declined after 1934, with only one publication appearing between 1934 and 1974 (1957). In 1974, the demise of the Tournay phenomenon was secured after 2 pupillographic studies showed it to be rare and marginal. This story is reviewed. Hypotheses are proposed in order to help unfold the controversy; anisocoria in lateral gaze should not be regarded as a myth, nor does it--or only rarely--correspond to a pupil reaction, or noumenon: it can usually be accounted for by a specific optical distortion (apparent without real anisocoria) and hence fits the Kantian definition of a phenomenon. An understanding of Tournay phenomenon is therefore of current relevance to the examination of the pupils to avoid misinterpretation of observed changes in the pupil.

  11. [Persistent skin reaction and Raynaud phenomenon after a sting by Echiichthys draco (great weever fish)].

    PubMed

    Mayser, P; Dreyer, F; Repp, H

    2003-07-01

    A 54-year-old recreational angler was stung in his right forefinger by Echiichthys draco. Within a few seconds he developed severe swelling with extreme pain sensation at the sting site, accompanied by dizziness and chill. Even under morphine therapy the pain symptoms were only slightly reduced. During the subsequent weeks, an erythema with marginate medium-sized scaling developed at the sting site and the patient experienced a approximately 50% reduced bending capacity of the forefinger and permanent numbness in this region. After 4 months, Raynaud phenomenon developed limited to the right forefinger. Great weever fishes (Echiichthys spp.) are the most venomous fishes in European waters. In humans, life-threatening sting reactions occur only in exceptional cases. As a commercial antiserum is not available, the therapy is mainly empiric (General measures of first aid and emergency medicine, the wound should be thoroughly washed). Patients should be informed that reduced motion ability, swelling or Raynaud's phenomenon can persist for several months.

  12. Paradoxical reaction of raynaud phenomenon following the repeated administration of iloprost in a patient with diffuse cutaneous systemic sclerosis.

    PubMed

    Barreira, Rebeca Iglesias; García, Belén Bardán; López, Mónica Granero; Legazpi, Iria Rodríguez; Díaz, Hortensia Álvarez; Penín, Isaura Rodríguez

    2012-10-01

    To report a paradoxical reaction of Raynaud phenomenon following the repeated administration of iloprost in a patient with diffuse cutaneous systemic sclerosis with vascular involvement. In January 2006, a 40-year-old male was diagnosed with diffuse cutaneous systemic sclerosis with pulmonary, esophageal, cutaneous, and vascular involvement (Raynaud phenomenon, with digital ulcers on his hands). In December 2008, treatment with iloprost was started due to worsening disease. Nine cycles of iloprost were administered at a rate of 0.5-1 ng/kg/min (6 hours per day, for 5 days every 6-8 weeks); the patient tolerated this treatment well. However, on the fourth day of cycles 10 and 11, the patient developed paradoxical Raynaud phenomenon in the hand with perfusion when the infusion was increased to 1 ng/kg/min, requiring treatment to be stopped. Treatment was continued during cycles 12 and 13 at 0.5 ng/kg/min; the patient tolerated the treatment well, although paradoxical Raynaud phenomenon occurred when the rate of infusion was increased. Raynaud phenomenon is extremely common in patients with scleroderma, and often is severe. Iloprost has vasodilating, antiplatelet, cytoprotective, and immunomodulating properties, and has been found to be an efficacious alternative to nifedipine for the treatment of Raynaud phenomenon in patients with scleroderma. The Naranjo probability scale indicated that iloprost was the probable cause of the paradoxical Raynaud phenomenon in this patient. This case demonstrates a probable relationship between the rate of infusion of iloprost and the paradoxical reaction of Raynaud phenomenon.

  13. 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…

  14. 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…

  15. 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.

  16. 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.

  17. [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.

  18. Computer experiments concerning palladium-deuterium and titanium-deuterium lattices - implications to phenomenon of low-energy nuclear reaction

    SciTech Connect

    Rao, K.R.; Chaplot, S.L.

    1996-12-01

    Short-lived large energy fluctuations (SLEFs) in solids, proposed by Khait, are known to be responsible for several anomalous properties in a variety of materials. The study of SLEFs in palladium-deuterium and titanium-deuterium lattices via computer experiments is reported. The relevance of these large energy fluctuations in penetrating coulombic barriers in these systems is discussed. Such dynamical effects arising from the phonon bath in solids may enhance nuclear reaction probabilities leading to cold fusion. Expected cold fusion reaction rates are reported taking into account the effective charges of the deuterium atoms in the solid and SLEF frequencies. 25 refs., 7 figs., 1 tab.

  19. 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

  20. [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.

  1. 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.

  2. 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

  3. Raynaud's phenomenon.

    PubMed

    O'connor, C M

    2001-09-01

    Many persons are affected by the phenomenon known as Raynaud's. Raynaud's is classified in 2 ways-as Raynaud's disease or Raynaud's syndrome. Classification is based on the presence of associated conditions. Raynaud's is characterized by vasospasm-induced color changes of the fingers, toes, and ears. The fingers are most commonly affected. Studies involving cause, diagnosis, and treatment have been instituted with varied results. Diagnosis is primarily based on clinical symptoms involving digital color changes. Treatment is aimed at prevention of attacks and includes medication, stress reduction, and avoidance of vasoconstricting agents. Whether the phenomenon will develop into a more serious condition with which Raynaud's is associated is important. This article describes the etiology, pathophysiology, diagnosis, treatment, and nursing implications with regard to Raynaud's.

  4. Vacuum phenomenon.

    PubMed

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

    2016-08-01

    This article describes the theory of the formation of the vacuum phenomenon (VP), the detection of the VP, the different medical causes, the different locations of the presentation of the VP, and the differential diagnoses. In the human body, the cavitation effect is recognized on radiological studies; it is called the VP. The mechanism responsible for the formation of the VP is as follows: 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. In the setting of expanding volume, the pressure within the space will decrease. The solubility of the gas in the enclosed space will decrease as the pressure of the space decreases. Decreased solubility allows a gas to leave a solution. Clinically, the pathologies associated with the VP have been reported to mainly include the normal joint motion, degeneration of the intervertebral discs or joints, and trauma. The frequent use of CT for trauma patients and the high spatial resolution of CT images might produce the greatest number of chances to detect the VP in trauma patients. The VP is observed at locations that experience a traumatic impact; thus, an analysis of the VP may be useful for elucidating the mechanism of an injury. When the VP is located in the abdomen, it is important to include perforation of the digestive tract in the differential diagnosis. The presence of the VP in trauma patients does not itself influence the final outcome.

  5. [Raynaud's phenomenon].

    PubMed

    Sprynger, M

    2004-06-01

    Raynaud's phenomenon (RP) is a common vascular disorder characterized by a recurrent transient vasospasm of the fingers and toes on exposure to cold or with emotional stress. Clinical criteria are used to distinguish patients with primary or idiopathic RP (formely Raynaud's disease) from those with secondary RP (formely Raynaud's syndrome). They include history, general physical examination, capillaroscopy, test for antinuclear antibody and erythrocyte sedimentation rate. More specific exams may be needed in selective cases. Excluding RP of occupational origin, the most common cause of secondary RP is a connective tissue disease (particularly scleroderma). RP may precede other clinical symptoms by several years, but most patients with RP will not progress to systemic disease. Nevertheless, primary RP may cause significant disability. We review the pathophysiology and clinical criteria of the disorder. Unfortunately, management of PR is still empirical and largely supportive.

  6. [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.

  7. Solid-State Reaction Mechanism and Deliquescence Phenomenon of K0.5Na0.5Nb0.7Al0.3O3 Ceramic

    NASA Astrophysics Data System (ADS)

    Gao, Lu; Zhou, Wancheng; Luo, Fa; Zhu, Dongmei

    2017-10-01

    Development of (K,Na)NbO3-based ceramics has attracted much attention in recent decades. In this work, K0.5Na0.5Nb0.7Al0.3O3 ceramic was prepared using conventional solid-state processing. A deliquescence phenomenon was observed when the specimen was exposed to moist atmosphere. The reaction mechanism and cause of deliquescence were investigated using x-ray diffraction analysis, scanning electron microscopy, energy-dispersive spectrometry, electron microprobe analysis, inductively coupled plasma mass spectrometry, and thermogravimetric/differential scanning calorimetric analysis. The results revealed interactions mainly amongst the raw materials K2CO3, Na2CO3, and Nb2O5 as well as K2CO3, Na2CO3, and Al2O3, which can influence the sintering behavior of the mixture. (K,Na)NbO3 and (K,Na)AlO2 were present in the sintered K0.5Na0.5Nb0.7Al0.3O3 ceramic, with the latter leading to deliquescence. During the sintering process, Al2O3 reacts with alkali oxides (Na2O and K2O), which are the decomposition products of carbonates, to form (K,Na)AlO2. In addition, Al2O3 is more likely to react with K2O compared with Na2O.

  8. 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

  9. Amplified-response-spectrum analysis of sodium-water reaction pressure waves. [LMFBR

    SciTech Connect

    Knittle, D.E.

    1981-10-28

    This report deals with a frequency spectrum evaluation of the SWAAM I predicted double rupture disc assembly operation pressure wave generated in the LLTR Series II A-2 test. It also evaluates the same wave predicted by the TRANSWRAP II code and the pressure wave actually measured upstream of the rupture disc assembly by the test instrumentation in Test A-2. The SWAAM I and TRANSWRAP II codes currently use the same analytical model to characterize the rupture disc until the disc strikes the knife edges. Thereafter, the SWAAM I code relies on analytical techniques to characterize the phenomena, whereas the TRANSWRAP II code uses empirical parameters based on A-2 test data to represent the disc behavior. Any differences in the predicted dynamic pipe loads caused by double rupture disc assembly operation, using the forcing functions predicted by the codes can, therefore, be traced to this difference.

  10. 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 ...

  11. CHEMICAL REACTION MECHANISM AND MODELIZATION OF DETERIORATION PHENOMENON OF HARDENED CEMENT DAMAGED BY CHEMICAL EROSION DUE TO MIXED ACID AQUEOUS SOLUTION

    NASA Astrophysics Data System (ADS)

    Miyamoto, Shintaro; Minagawa, Hiroshi; Hisada, Makoto

    This study measured the mass decrease rate of the hardened cement specimens which deteriorated by sulfuric acid, hydrochloric acid, nitric acid and mixed acid which mixed these acids (i.e. sulfuric acid, hydrochloric acid, nitric acid) for the purpose of clarify the these chemical reaction mechanism. As a result, it was clarified that mass decrease rate of hardened cement is greatly dependent on concentration of sulfuric acid when mixed acids containing sulfuric acid and other acid (i.e. hydrochloric acid or nitric acid) act on hardened cement. In this study, it was apprehended that the cause of this chemical reaction mechanism is influence of molar fraction of sulfuric acid and it was indicated that this chemical reaction mechanism could be explained by Gibbs free energy and chemical kinetics. Moreover, in this study, it was proposed that prediction model of mass decrease rate based on these theories.

  12. Increased reaction time variability in attention-deficit hyperactivity disorder as a response-related phenomenon: evidence from single-trial event-related potentials.

    PubMed

    Saville, Christopher W N; Feige, Bernd; Kluckert, Christian; Bender, Stephan; Biscaldi, Monica; Berger, Andrea; Fleischhaker, Christian; Henighausen, Klaus; Klein, Christoph

    2015-07-01

    Increased intra-subject variability (ISV) in reaction times (RTs) is a promising endophenotype for attention-deficit hyperactivity disorder (ADHD) and among the most robust hallmarks of the disorder. ISV has been assumed to represent an attentional deficit, either reflecting lapses in attention or increased neural noise. Here, we use an innovative single-trial event-related potential approach to assess whether the increased ISV associated with ADHD is indeed attributable to attention, or whether it is related to response-related processing. We measured electroencephalographic responses to working memory oddball tasks in patients with ADHD (N = 20, aged 11.3 ± 1.1) and healthy controls (N = 25, aged 11.7 ± 1.1), and analysed these data with a recently developed method of single-trial event-related potential analysis. Estimates of component latency variability were computed for the stimulus-locked and response-locked forms of the P3b and the lateralised readiness potential (LRP). ADHD patients showed significantly increased ISV in behavioural ISV. This increased ISV was paralleled by an increase in variability in response-locked event-related potential latencies, while variability in stimulus-locked latencies was equivalent between groups. This result held across the P3b and LRP. Latency of all components predicted RTs on a single-trial basis, confirming that all were relevant for speed of processing. These data suggest that the increased ISV found in ADHD could be associated with response-end, rather than stimulus-end processes, in contrast to prevailing conceptions about the endophenotype. This mental chronometric approach may also be useful for exploring whether the existing lack of specificity of ISV to particular psychiatric conditions can be improved upon. © 2014 Association for Child and Adolescent Mental Health.

  13. 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.

  14. [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)

  15. 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.

  16. 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.

  17. 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.

  18. 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)

  19. 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)

  20. The Lazarus phenomenon

    PubMed Central

    Adhiyaman, Vedamurthy; Adhiyaman, Sonja; Sundaram, Radha

    2007-01-01

    Even though Lazarus phenomenon is rare, it is probably under reported. There is no doubt that Lazarus phenomenon is a reality but so far the scientific explanations have been inadequate. So far the only plausible explanation at least in some cases is auto-PEEP and impaired venous return. In patients with PEA or asystole, dynamic hyperinflation should considered as a cause and a short period of apnoea (30-60 seconds) should be tried before stopping resuscitation. Since ROSC occurred within 10 minutes in most cases, patients should be passively monitored for at least 10 minutes after the cessation of CPR before confirming death. PMID:18065707

  1. 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)

  2. Raynaud's phenomenon (primary)

    PubMed Central

    2008-01-01

    Introduction Raynaud’s phenomenon is an episodic vasospasm of the peripheral arteries, causing pallor followed by cyanosis and redness with pain and sometimes paraesthesia. On rare occasions it can lead to ulceration of the fingers and toes (and in some cases of the ears or nose). This review focuses on primary (idiopathic) Raynaud's phenomenon occurring in the absence of an underlying disease. The prevalence of primary Raynaud's phenomenon varies by sex, country, and exposure to workplace vibration. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical question: What are the effects of treatments for primary Raynaud’s phenomenon? We searched: Medline, Embase, The Cochrane Library, and other important databases up to May 2008 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 15 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: amlodipine, diltiazem, exercise, inositol nicotinate, keeping warm, moxisylyte (thymoxamine), naftidrofuryl oxalate, nicardipine, nifedipine, prazosin, and smoking cessation. PMID:19445785

  3. Raynaud's phenomenon (primary)

    PubMed Central

    2011-01-01

    Introduction Raynaud’s phenomenon is an episodic vasospasm of the peripheral arteries, causing pallor, followed by cyanosis and redness with pain, and sometimes paraesthesia. On rare occasions it can lead to ulceration of the fingers and toes (and in some cases of the ears or nose). This review focuses on primary (idiopathic) Raynaud's phenomenon, occurring in the absence of an underlying disease. The prevalence of primary Raynaud's phenomenon varies by sex, country, and exposure to workplace vibration. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical question: What are the effects of treatments for primary Raynaud’s phenomenon? We searched: Medline, Embase, The Cochrane Library, and other important databases up to May 2010 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 16 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: amlodipine, diltiazem, exercise, inositol nicotinate, keeping warm, moxisylyte (thymoxamine), naftidrofuryl oxalate, nicardipine, nifedipine, prazosin, and smoking cessation. PMID:21401971

  4. Raynaud's phenomenon (primary)

    PubMed Central

    2013-01-01

    Introduction Raynaud’s phenomenon is an episodic, reversible vasospasm of the peripheral arteries (usually digital). It causes pallor, followed by cyanosis and/or redness, often with pain and, at times, paraesthesia. On rare occasions, it can lead to ulceration of the fingers and toes (and, in some cases, of the ears or nose). This review focuses on primary (idiopathic) Raynaud's phenomenon, occurring in the absence of an underlying disease. The prevalence of primary Raynaud's phenomenon varies by sex, country, and exposure to workplace vibration. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical question: What are the effects of drug treatments for primary Raynaud’s phenomenon? We searched: Medline, Embase, The Cochrane Library, and other important databases up to August 2013 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 9 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: amlodipine, diltiazem, nicardipine, and nifedipine. PMID:24112969

  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 (secondary)

    PubMed Central

    2008-01-01

    Introduction Raynaud’s phenomenon is episodic vasospasm of the peripheral vessels, causing pallor followed by cyanosis and redness with pain and sometimes paraesthesia, and, rarely, ulceration of the fingers and toes. It presents as episodic colour changes of the digits, usually in response to cold exposure or stress. The classic triphasic colour change is white (ischaemia), then blue (deoxygenation), then red (reperfusion). Raynaud’s phenomenon can be primary (idiopathic) or secondary to several different conditions and causes. This review deals with secondary Raynaud’s phenomenon. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of self-help measures for secondary Raynaud’s phenomenon? What are the effects of drug treatments for secondary Raynaud’s phenomenon? We searched: Medline, Embase, The Cochrane Library, and other important databases up to May 2007 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 25 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review, we present information relating to the effectiveness and safety of the following interventions: alpha-blockers; angiotensin-converting enzyme (ACE) inhibitors; angiotensin II receptor antagonists; antithrombotics/inhibitors of platelet aggregation; biofeedback; calcium channel blockers; endothelin-1 receptor antagonists; glyceryl trinitrate (transdermal); hand exercises; inositol nicotinate; moxisylyte; naftidrofuryl oxylate; phosphodiesterase inhibitors; prostaglandins (oral, intravenous); relaxation therapy

  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 charge transfer transition phenomenon and microstructure of Eu{sup 3+}-doped NaCaPO{sub 4} phosphors sintered with NH{sub 4}Cl flux via solid-state reaction

    SciTech Connect

    Peng, Yu-Ming; Su, Yan-Kuin; Yang, Ru-Yuan

    2013-05-15

    Graphical abstract: This paper describes: The charge transfer transition phenomenon and microstructure of Eu{sup 3+}-doped NaCaPO{sub 4} phosphors sintered with NH{sub 4}Cl flux via solid-state reaction. The emission intensity of NaCa{sub 0.95}PO{sub 4}:0.05Eu{sup 3+} phosphors with 2 wt.% NH{sub 4}Cl flux is enhanced as the sintering temperature was increased from 800 °C to 1000 °C and reveals the maximum value at 1000 °C. Photoluminescence emission spectra of NaCa{sub 0.95}PO{sub 4}:0.05Eu{sup 3+} phosphors with 2 wt.% NH{sub 4}Cl flux sintered at various sintering temperature for 3 h via solid state reaction method (λ{sub ex} = 270 nm). Highlights: ► NH{sub 4}Cl flux is helpful for enhancing the crystallization degree and decreasing surface defects. ► A single phase of NaCaPO{sub 4}:Eu{sup 3+} phosphor was observed as the sintering temperature was increased from 800 °C to 1000 °C. ► The intensity of the excitation peaks displays a maximum value at 1000 °C. ► The NaCaPO{sub 4} host added with NH{sub 4}Cl flux and sintered at the different temperature can affect the morphology. ► The NaCaPO{sub 4} host added with NH{sub 4}Cl flux and sintered at the different temperature can affect fluorescent properties. - Abstract: NaCa{sub 0.95}PO{sub 4}:0.05Eu{sup 3+} phosphors with 2 wt.% NH{sub 4}Cl flux sintered at various sintering temperature (800, 900, 1000, 1100 °C) for 3 h under air atmosphere were synthesized successfully via solid state reaction method. It is found that the addition of NH{sub 4}Cl flux and different sintering temperatures can affect the morphology and fluorescent properties of NaCa{sub 0.95}PO{sub 4}:0.05Eu{sup 3+} phosphor. The X-ray diffractions show a single phase and the microstructure observations show uniform morphologies for NaCa{sub 0.95}PO{sub 4}:0.05Eu{sup 3+} phosphors sintered at the range from 900 °C to 1000 °C, indicating that addition of 2 wt.% NH{sub 4}Cl flux is helpful for enhancing the crystallization, thus

  10. 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. Copyright © 2015 Elsevier España, S.L.U. and Sociedad Española de Reumatología y Colegio Mexicano de Reumatología. All rights reserved.

  11. Winter Cardiovascular Diseases Phenomenon

    PubMed Central

    Fares, Auda

    2013-01-01

    This paper review seasonal patterns across twelve cardiovascular diseases: Deep venous thrombosis, pulmonary embolism, aortic dissection and rupture, stroke, intracerebral hemorrhage, hypertension, heart failure, angina pectoris, myocardial infarction, sudden cardiac death, venricular arrythmia and atrial fibrillation, and discuss a possible cause of the occurrence of these diseases. There is a clear seasonal trend of cardiovascular diseases, with the highest incidence occurring during the colder winter months, which have been described in many countries. This phenomenon likely contributes to the numbers of deaths occurring in winter. The implications of this finding are important for testing the relative importance of the proposed mechanisms. Understanding the influence of season and other factors is essential when seeking to implement effective public health measures. PMID:23724401

  12. 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.

  13. 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.

  14. 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.

  15. [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.

  16. 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

  17. Raynaud's phenomenon induced by sulphasalazine.

    PubMed Central

    Reid, J.; Holt, S.; Housley, E.; Sneddon, D. J.

    1980-01-01

    Sulphasalazine-induced Raynaud's phenomenon is reported in a patient who showed no other features of a drug-induced lupus syndrome. The vascular disturbance disappeared when the drug was withdrawn on 3 occasions. A simple technique for assessing the circulatory abnormality in Raynaud's phenomenon is described. PMID:6104805

  18. 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.

  19. 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.

  20. [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.

  1. [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.

  2. The Tullio phenomenon: a neurologically neglected presentation.

    PubMed

    Kaski, Diego; Davies, R; Luxon, L; Bronstein, A M; Rudge, P

    2012-01-01

    The Tullio phenomenon refers to sound-induced disequilibrium or oscillopsia. Patients with this condition frequently present to neurologists, many of whom are unfamiliar with the condition and its diagnostic criteria. Indeed, due to the unusual nature of the symptoms patients are often misdiagnosed as having psychiatric disturbances. Tullio patients describe disequilibrium, auditory and visual symptoms, which are recurrent, brief, and often triggered by loud noises or middle ear pressure changes, e.g. the Valsalva manoeuvre. Many cases are associated with superior semicircular canal dehiscence (SCCD). Early work suggested that the presence of sound-induced torsional eye movements and visual field tilts were consequent upon a utricular-mediated ocular tilt reaction. However, more recent evidence from imaging and oculographic research, as well as data from our patient series indicates that these ocular abnormalities are usually the result of superior semicircular canal stimulation. The clinical history and a focussed examination are often sufficient to make the diagnosis, which can be confirmed with high resolution CT imaging of the temporal bones. In some patients, surgical occlusion or resurfacing of the affected canal can ameliorate symptoms and signs. The aim of this paper is two-fold: Firstly, to review the clinical features of the Tullio phenomenon, and secondly, to highlight our own observations in three cases with a new clinical syndrome consisting of Tullio's phenomenon with bilateral vestibular failure, a pure horizontal nystagmus in response to sound, and no evidence of canal dehiscence.

  3. 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.

  4. Pink tooth phenomenon: an enigma?

    PubMed

    Thapar, Raveena; Choudhry, Swati; Sinha, Anju; Bali, Ruchita; Shukla, Deepika

    2013-10-01

    The appearance of pink teeth is a common phenomenon which has been observed after death in certain circumstances on post-mortem examination. Extra fibrinolytic activity of pulp facilitates rapid breakdown of red blood cells and diffusion of hemoglobin and its derivatives to flow into dentine. We reviewed various studies on pink tooth phenomenon which have stated the various factors that lead to pink tooth formation. Most of the authors have stressed that post-mortem pink teeth must not be considered as a reliable odontological parameter for determining cause of death. No correlation has been found between the occurrence of pink teeth and the cause of death but condition of the surroundings certainly plays an important role in the development of this phenomenon. This paper reviews the factors and conditions responsible for formation of pink teeth. Copyright © 2013 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  5. 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…

  6. 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…

  7. Wellness as a worldwide phenomenon?

    PubMed

    Elliott, Heather; Bernstein, Jennifer; Bowman, Diana M

    2014-10-01

    This article examines the concept of wellness through a comparative political economy and legal framework. It asks whether wellness, an increasingly defined term within US federal and state legislative instruments including, for example, the Patient Protection and Affordable Care Act, is primarily a US-centric phenomenon. Or is wellness, in its various different guises, a worldwide phenomenon? By focusing on three distinctly different jurisdictions - the United States, Germany, and Australia - this article examines wellness through the lens of employers, the health care system, employment and tort law, and the greater political economy. It notes that while improving employee health, well-being, and productivity is common across the three countries and their respective cultures, the focus on wellness as a distinct legal concept is unique to the United States. Copyright © 2014 by Duke University Press.

  8. STUDIES ON THE SHWARTZMAN PHENOMENON

    PubMed Central

    Klein, Herbert M.

    1932-01-01

    Formalin induces a considerable change in meningococcus culture filtrates. This consists of a marked decrease in toxidty as concerns both the Shwartzman phenomenon and the lethal effect, with relative preservation of the antibody-combining capacity and antigenicity. A similar modification occurs spontaneously in meningococcus culture filtrates on standing. Inasmuch as these changes parallel those occurring in the conversion of diphtheria toxin into toxoid, it is justifiable to consider such altered meningococcus toxin as meningococcus toxoid. PMID:19870087

  9. Nutcracker Phenomenon and Nutcracker Syndrome

    PubMed Central

    Kurklinsky, Andrew K.; Rooke, Thom W.

    2010-01-01

    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. PMID:20511485

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. The phenomenon of microbial uncultivability.

    PubMed

    Epstein, S S

    2013-10-01

    Most of the microbial diversity on our planet cannot be cultivated, and remains inaccessible. To bring the missing species into culture, microbiologists have introduced over the past decade a number of innovations aiming to meet the demands of new microbes and better mimic their natural conditions. This resulted in a significant increase in microbial recovery yet the real reasons why so many microbes do not grow on artificial media remain largely unknown. The recently proposed scout model of microbial life cycle may provide a partial explanation for the phenomenon. It postulates that transition from dormancy to activity is a stochastic process originating in noise-driven bistability. The model helps explain several otherwise perplexing observations, and informs the future cultivation efforts. Copyright © 2013. Published by Elsevier Ltd.

  16. Phosphene phenomenon: a new concept.

    PubMed

    Bókkon, István

    2008-05-01

    This paper proposes a new biopsychophysical concept of phosphene phenomenon. Namely, visual sensation of phosphenes is due to the intrinsic perception of ultraweak bioluminescent photon emission of cells in the visual system. In other words, phosphenes are bioluminescent biophotons in the visual system induced by various stimuli (mechanical, electrical, magnetic, ionizing radiation, etc.) as well as random bioluminescent biophotons firings of cells in the visual pathway. This biophoton emission can become conscious if induced or spontaneous biophoton emission of cells in the visual system exceeds a distinct threshold. Neuronal biophoton communication can occur by means of non-visual neuronal opsins and natural photosensitive biomolecules. Our interpretation is in direct connection with the functional roles of free radicals and excited biomolecules in living cells.

  17. 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. Copyright © 2015. Published by Elsevier Ltd.

  18. Theory and Calculation of the Phosphorescence Phenomenon.

    PubMed

    Baryshnikov, Gleb; Minaev, Boris; Ågren, Hans

    2017-05-10

    Phosphorescence is a phenomenon of delayed luminescence that corresponds to the radiative decay of the molecular triplet state. As a general property of molecules, phosphorescence represents a cornerstone problem of chemical physics due to the spin prohibition of the underlying triplet-singlet emission and because its analysis embraces a deep knowledge of electronic molecular structure. Phosphorescence is the simplest physical process which provides an example of spin-forbidden transformation with a characteristic spin selectivity and magnetic field dependence, being the model also for more complicated chemical reactions and for spin catalysis applications. The bridging of the spin prohibition in phosphorescence is commonly analyzed by perturbation theory, which considers the intensity borrowing from spin-allowed electronic transitions. In this review, we highlight the basic theoretical principles and computational aspects for the estimation of various phosphorescence parameters, like intensity, radiative rate constant, lifetime, polarization, zero-field splitting, and spin sublevel population. Qualitative aspects of the phosphorescence phenomenon are discussed in terms of concepts like structure-activity relationships, donor-acceptor interactions, vibronic activity, and the role of spin-orbit coupling under charge-transfer perturbations. We illustrate the theory and principles of computational phosphorescence by highlighting studies of classical examples like molecular nitrogen and oxygen, benzene, naphthalene and their azaderivatives, porphyrins, as well as by reviewing current research on systems like electrophosphorescent transition metal complexes, nucleobases, and amino acids. We furthermore discuss modern studies of phosphorescence that cover topics of applied relevance, like the design of novel photofunctional materials for organic light-emitting diodes (OLEDs), photovoltaic cells, chemical sensors, and bioimaging.

  19. 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

  20. Leidenfrost phenomenon on conical surfaces

    NASA Astrophysics Data System (ADS)

    Hidalgo-Caballero, S.; Escobar-Ortega, Y.; Pacheco-Vázquez, F.

    2016-09-01

    The Leidenfrost state is typically studied by placing droplets on flat or slightly curved surfaces. Here this phenomenon is investigated by depositing water in hot conical bowls. We found that this phase exists even for large amounts of liquid in very narrow cones without considerable effect of the confinement on the Leidenfrost transition temperature TL. At a fixed temperature, T >TL , the total evaporation time τ has a nonmonotonic dependence on the angle of confinement θ : for large volumes (˜20 ml) on flat surfaces (θ ˜0∘ ), vapor chimneys appear and accelerate the evaporation rate, their frequency diminishes as θ augments and becomes zero at a certain angle θc, at which τ reaches its maximum value; then, τ decreases again at larger angles because the vapor layer holding up the water becomes thinner due to the increase of hydrostatic pressure and because the geometry facilitates the vapor expulsion along the conical wall. For small volumes (˜1 ml), surface tension mainly determines the drop curvature and the lifetime is practically independent of θ . Different chimney regimes and oscillation patterns were observed and summarized in a phase diagram. Finally, we developed a simple model to decipher the shape adopted by the liquid volume and its evolution as a function of time, and the predictions are in good agreement with the experimental results.

  1. 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).

  2. Surface phenomenon in Electrochemical Systems

    NASA Astrophysics Data System (ADS)

    Gupta, Tanya

    Interfaces play a critical role in the performance of electrochemical systems. This thesis focusses on interfaces in batteries and covers aspects of interfacial morphologies of metal anodes, including Silicon, Lithium and Zinc. Growth and cycling of electrochemically grown Lithium and Zinc metal structures is investigated. A new morphology of Zinc, called Hyper Dendritic Zinc is introduced. It is cycled against Prussian Blue Analogues and is shown to improve the performance of this couple significantly. Characterization of materials is done using various electron microscopy techniques ranging from Low Energy Electron Microscope (LEEM), to high energy Transmission Electron Microscope (TEM). LEEM is used for capturing subtle surface phenomenon occurring during epitaxial process of electrolyte on anode. The system studied is Silicon (100) during Chemical Vapor Deposition of Ethylene Carbonate. A strain driven relaxation theory is modeled to explain the unusual restructuring of Si substrate. The other extreme, TEM, is often used to study electrochemical processes, without clear understanding of how the high-energy electron beam can influence the sample under investigation. Here, we study the radiolysis in liquid cell TEM and emphasize on the enhancement of radiation dose at interfaces of the liquid due to generation of secondary and backscattered electrons from adjoining materials. It is shown that this effect is localized in a 10 nm region around the interface and can play a dominating role if there is an interface of liquid with heavy metals like Gold and Platinum which are frequently used as electrode materials. This analysis can be used to establish guidelines for experimentalists to follow, for accurate interpretation of their results.

  3. 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.

  4. 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

  5. Measurement of cold challenge responses in primary Raynaud's phenomenon and Raynaud's phenomenon associated with systemic sclerosis.

    PubMed Central

    O'Reilly, D; Taylor, L; el-Hadidy, K; Jayson, M I

    1992-01-01

    Using computed thermography continuous temperature recordings were made before and after cold challenge of the fingers of control subjects and patients with primary Raynaud's phenomenon and Raynaud's phenomenon associated with systemic sclerosis. Basal skin temperature measurements (Tpre) were significantly lower in patients with primary Raynaud's phenomenon and Raynaud's phenomenon associated with systemic sclerosis than in the controls. Temperatures immediately after cold challenge (T0) were significantly lower in patients with primary Raynaud's phenomenon and Raynaud's phenomenon associated with systemic sclerosis than in controls. The lag phase before the start of temperature recovery (Tlag) was significantly greater in patients with primary Raynaud's phenomenon and Raynaud's phenomenon associated with systemic sclerosis than in control subjects. The maximum recovery index (R%) was significantly less in patients with primary Raynaud's phenomenon and Raynaud's phenomenon associated with systemic sclerosis than in controls. The maximum rate of change of temperature during the rapid phase of rewarming (Gmax) was significantly greater in controls than in patients with primary Raynaud's phenomenon and Raynaud's phenomenon associated with systemic sclerosis. Discriminant analysis showed that the dynamic parameters of rewarming (Tlag, Gmax, and R%) showed greater variation between the patients with primary Raynaud's phenomenon and those with Raynaud's phenomenon associated with systemic sclerosis than did Tpre or T0. This method of analysis of cold challenge will be used in studies of the effects of treatment of Raynaud's phenomenon. PMID:1466594

  6. 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

  7. 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.

  8. 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.

  9. Terrorism as a Social and Legal Phenomenon

    ERIC Educational Resources Information Center

    Serebrennikova, Anna; Mashkova, Yekaterina

    2017-01-01

    This article examines the concept of terrorism as a social and legal phenomenon, its international legal and criminal-legal characteristics. Highlighted are the main aspects of cooperation of the states and the international community to counter terrorist activities. Terrorism as a social phenomenon is determined by paragraph 1 of article 3 of the…

  10. 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.

  11. Evaluating method for the double image phenomenon of LED lighting

    NASA Astrophysics Data System (ADS)

    Wu, Wen-Hong; Kuo, Chao-Hui; Hung, Min-Wei; Huang, Kuo-Cheng

    In recent years, the overriding advantages long life, high efficiency, small size and short reaction time have made LED become a viable alternative to conventional light sources. LED lighting sources are usually composed of several individual LED cells which must be mounted on a panel as a lighting module. Being composed of several individual LED cells, the LED sources will cause the double image phenomenon. The double image phenomenon is more obvious when the LED sources are more closer, such as LED table lamp, and limits the applications of LED sources. By using a proper secondary optical lens, the double image phenomenon can be reduced. In this research, an evaluating method based on image processing is developed for the double image phenomenon of a LED sources. By analyzing the gray-scale of the grabbed image which is obtained by putting a rob under a LED source, an index of double image can be established and be a criterion to judge different LED sources. Furthermore, a series of LED lighting simulations are shown in this paper and several type of secondary optical lens are compared and discussed in this paper as well.

  12. The Fleischmann-Pons phenomenon; Different perspective

    SciTech Connect

    Ray, M.K.S.; Saini, R.D.; Das, D.; Chattopadhyay, G.; Parthasarathy, R.; Garg, S.P.; Venkataramani, R.; Sen, B.K.; Iyengar, T.S.; Kutty, K.K. )

    1992-11-01

    This paper reports on attempts which have been made to initiate the Fleischmann-Pons phenomenon through selective perturbations during experimental studies in divided electrolytic cells. Despite wide variations in the operating parameters and the attainment of high loading (sometimes up to D/Pd [approx] 2), the phenomenon was not observed either during the unperturbed electrolysis or on physical perturbation. However, instances of its occurrence were observed when the state of equilibrium of the deuterated cathode (having a scale free portion) was chemically perturbed by oxygen. This observation, viewed in light of available information, is indicative of oxygen playing a vital role in the phenomenon.

  13. [Gregg phenomenon and garden hose effect].

    PubMed

    Schipke, J D; Frehen, D

    2001-05-01

    Under physiologic circumstances, cardiac function determines myocardial oxygen consumption and consequently coronary perfusion. Surprisingly, in a reverse direction, improved coronary perfusion also increased myocardial oxygen consumption and contractile function. This experimental finding, now 40 years old, is termed the Gregg phenomenon. Some 10 years later, in experiments by Arnold and co-workers, an isolated increase in perfusion pressure improved ventricular function. In this context, the term 'gardenhose effect' was coined, implying a hydraulic explanation of the Gregg phenomenon. In the following, we attempt to distinguish the Gregg phenomenon from the gardenhose effect and to critically evaluate them.

  14. 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.

  15. The lean hunting phenomenon in gasoline engines

    SciTech Connect

    Tanaka, M.; Mochizuki, S.; Nishiwaki, N.; Miyake, M.

    1987-01-01

    A quite interesting self-excited oscillation phenomenon in engine speed, which may not be explained with the classical theory of mechanical hunting, is studied experimentally. The effects of the various engine operating variables on the phenomenon are examined using a four cycle single cylinder gasoline engine with an inertia governor. It was found that the phenomenon occurs when engines are operated at a lean air fuel ratio under light load conditions, and that the hunting phenomenon is ascribable to the temporary shift in air fuel ratio from the steady state value. This shift in air fuel ratio occurs due to the fuel flow delay into the cylinder caused by the fact that the fuel flow into the cylinder cannot follow the movement of the throttle valve.

  16. Orgasm Induced Seizures: A Rare Phenomenon.

    PubMed

    Chaukimath, S P; Patil, P S

    2015-01-01

    A variety of stimuli can cause reflex seizures, Some triggers include light, music and cognitive phenomenon. There are case reports however where the phenomenon of sexual activity has been a trigger for epileptic seizures. Most of these cases reported are in women so far, and were found to be localized to right cerebral hemisphere. We report a case of a 36-year-old male with orgasm-induced seizures, with other atypical features compared to majority of previous reports.

  17. 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.

  18. 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

  19. 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)

  20. 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.

  1. Resonant Phenomenon in a Stochastic Delayed Bistable Chemical System

    NASA Astrophysics Data System (ADS)

    Li, Chunxuan; Yang, Tao

    2015-06-01

    In this paper, the resonant phenomenon for a bistable chemical system in the presence of noises and delayed feedback is investigated. The signal-to-noise ratio (SNR) is calculated when periodic signal is introduced additively (or multiplicatively). The impacts of the parameter μ of the reaction, time delay τ, strength K of the feedback loop, multiplicative ( D) and additive ( Q) noise strengths and cross-correlation strength λ between two noises on the SNR are discussed. When the periodic signal is introduced additively, our results show (i) the SNR as a function of the parameter μ exhibits a maximum, the existence of the maximum is a characteristic of the parametric resonance (PR) phenomenon; (ii) the SNR as a function of D exhibits only a maximum, however, for the case of SNR as a function of Q exhibits not only a maximum, but also a minimum. The existence of the maximum and minimum in the SNR is the identifying characteristics of the stochastic resonance (SR) and reverse-resonance (RR); and (iii) the increases of τ, K and λ enhance the SR and weaken the RR. Finally, we compare the resonant phenomenon for the additive periodic signal with that for multiplicative one in the chemical system.

  2. 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.

  3. 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.

  4. Measurement of thermoacoustic convection heat transfer phenomenon

    NASA Technical Reports Server (NTRS)

    Parang, M.; Salah-Eddine, A.

    1983-01-01

    In this paper the results of an experimental investigation of thermoacoustic convection (TAC) heat transfer phenomenon in both zero-gravity and gravity environment are presented and compared with pure conduction heat transfer. The numerical solutions of the governing equations obtained by others for TAC heat transfer phenomenon are also discussed. The experimental results show that for rapid heating rate at a boundary, the contribution of TAC heat transfer to a gas could be significantly (one order of magnitude) higher than heat transfer rate from pure conduction. The results also show significantly reduced transient time in heat transfer processes involving thermoacoustic convective heat transfer mode in both space and gravity environment.

  5. 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.

  6. 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

  7. 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

  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. 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…

  10. 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…

  11. 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…

  12. 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)

  13. 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…

  14. Return to the "Getting Better Phenomenon"

    ERIC Educational Resources Information Center

    Carley, Glenn

    2007-01-01

    A school social work intervention called the "Getting Better Phenomenon" is redesigned as a curriculum resource for eighth- and ninth-grade teachers. The activities in the curriculum represent a synergy of provincial learning expectations; academic assessment and evaluation structures; teacher-guided delivery of student-generated "course" content;…

  15. 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…

  16. 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…

  17. 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)

  18. 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…

  19. 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.

  20. 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…

  1. [Raynaud's phenomenon in occupational vibration exposure].

    PubMed

    Letzel, S; Muttray, A

    2013-03-01

    A 34-year-old female stonemason was referred for expert opinion. The question at issue was, whether she suffered from vibration-induced white finger disease. She was exposed to high-frequency hand-arm vibrations for many years. She reported white finger attacks at the long fingers, which were associated with cold weather. Until this point, physical findings were normal. The cold water provocation test showed a slight delay of the rewarming for the long fingers of the right hand. The nailfold capillary microscopy was normal. The slight Raynaud's phenomenon was recognized as an occupational disease with a diagnosis of vibration-induced white finger disease. About three years later, the symptoms of the Raynaud's phenomenon had deteriorated, although the patient had finished working with vibrating tools. The cold water provocation test confirmed the deterioration. At this time, the patient had inflamed swellings of some joints caused by rheumatoid arthritis. The differential diagnosis of a Raynaud's phenomenon should include occupational causes. Occupational history is diagnostically indicative. If an occupational disease is assumed, a report must be filed. With respect to German social law, the deterioration of the Raynaud's phenomenon was caused by the rheumatoid arthritis, which is regarded as independent from the job. © Georg Thieme Verlag KG Stuttgart · New York.

  2. Systemic lupus erythematosus and Raynaud's phenomenon*

    PubMed Central

    Heimovski, Flavia Emilie; Simioni, Juliana A.; Skare, Thelma Larocca

    2015-01-01

    BACKGROUND Patients with systemic lupus erythematosus seem to belong to different serological and clinical subgroups of the disease. Genetic background can cause the appearance of these subgroups. OBJECTIVE To determine whether Brazilian patients who have systemic lupus erythematosus and Raynaud's phenomenon differ from those who do not. METHODS Retrospective analysis of 373 medical records of systemic lupus erythematosus patients studied for demographic, clinical and serological data. A comparative analysis was performed of individuals with and without RP. RESULTS There was a positive association between Raynaud's phenomenon and age at diagnosis (p=0.02), presence of anti-Sm (p=0.01) antibodies and anti-RNP (p<0.0001). Furthermore, a negative association was found between Raynaud's phenomenon and hemolysis (p=0.01), serositis (p=0.01), glomerulonephritis (p=0.0004) and IgM aCL (p=0.004) antibodies. CONCLUSION Raynaud's phenomenon patients appear to belong to a systemic lupus erythematosus subset with a spectrum of clinical manifestations located in a more benign pole of the disease. PMID:26734864

  3. 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

  4. Endoscopic thoracic sympathicotomy for Raynaud's phenomenon.

    PubMed

    Matsumoto, Yasushi; Ueyama, Takeshi; Endo, Masamitsu; Sasaki, Hisao; Kasashima, Fuminori; Abe, Yoshinobu; Kosugi, Ikuko

    2002-07-01

    For many years, thoracic sympathectomy via open surgery was not used to treat Raynaud's phenomenon because of the invasiveness of this procedure and the poor long-term outcomes associated with it. However, with the introduction of endoscopic surgery, thoracic sympathectomy (or sympathicotomy) has been performed by some surgeons as a less invasive surgical option for patients with Raynaud's phenomenon. The less invasive procedure has the possibility of emphasizing merits of sympathectomy. The purpose of this study was to reevaluate the efficacy of sympathicotomy for Raynaud's phenomenon with endoscopic technique and its range of applicability. Between December 1992 and August 2001, endoscopic thoracic sympathicotomy (ETS) was performed in 28 patients with Raynaud's phenomenon (of a total of 502 patients with autonomic disorders who underwent ETS) at National Kanazawa Hospital. We considered indications for surgical treatment of Raynaud's phenomenon to include severe chronic symptoms or nonhealing digital ulceration refractory to intensive medical therapy. All patients were mailed a self-assessment questionnaire after surgery to determine the immediate and long-term results of the procedure. Data from both initial and long-term follow-up examinations were obtained. Fifty-four ETS procedures were performed in 28 patients. No operative mortality was seen, and no occurrence of major complications necessitated open surgery. Initial resolution or improvement of symptoms was achieved in 26 of 28 patients (92.9%). However, later in the postoperative period, symptoms recurred in 23 of 28 patients (82.1%), although no recurrence of digital ulceration was seen throughout our observation. At the final follow-up examination (median follow-up period, 62.5 months), 25 patients (89.3%) reported overall improvement of the frequency and severity of their symptoms. Despite the high rate of recurrence, ETS clearly produced a high rate of initial relief. ETS did indeed promote healing

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Lorentz Symmetry as AN Emergent Phenomenon

    NASA Astrophysics Data System (ADS)

    Consoli, M.

    2015-01-01

    The vacuum of quantum gravity is believed to be a form of `space-time foam' which resembles a turbulent fluid. In this perspective, it is conceivable that Lorentz symmetry might be an emergent phenomenon. However, this idea of an underlying turbulent ether is not strictly peculiar of quantum gravity. This general picture suggests an alternative interpretation of the stochastic signal observed in the present ether-drift experiments with potentially important implications for both relativity and gravity.

  12. 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

  13. Glomus Tumor Presenting as Raynaud's Phenomenon

    PubMed Central

    Abdelrahman, M. H.; Hammoudeh, M.

    2012-01-01

    Glomus tumors are rare tumors that often include hands and feet; they present characteristically with paroxysmal pain, exquisite point tenderness, and cold sensitivity. Such diagnosis needs to be confirmed by imaging like ultrasound and magnetic resonance imaging (MRI). Surgical excision is the treatment of choice for glomus tumors. There are only few case reports of glomus tumors in association with Raynaud's phenomenon; this is considered to be the 4th case. PMID:22811722

  14. The feedback phenomenon applied to underwater acoustics

    NASA Astrophysics Data System (ADS)

    Roux, Philippe; Jordan, Jason E.; Kuperman, W. A.

    2002-11-01

    People are familiar with the feedback phenomenon that results in the loud sound heard when a musician plays an electric instrument directly into a speaker. Feedback occurs when a source and a receiver are connected both acoustically through the propagation medium and electrically through an amplifier in such way that the received signal is simultaneously and continuously added to the emitted signal. A resonance is then obtained when the emitter and the receiver are in phase. The resonant frequency appears to be highly sensitive to fluctuations of the propagation medium. The feedback phenomenon has been experimentally demonstrated as a means to monitor the temperature fluctuation of a shallow water environment [''Acoustic monitoring of the sea medium variability: experimental testing of new methods,'' by A. V. Furduev, Acoust. Phys. 47, No. 3, 361-368 (2001)]. The goal of our work is to reproduce the feedback experiment using an alternative method that decomposes the feedback phenomenon into an iterative process. Successful reproduction of the feedback is accomplished using a step-by-step algorithm which details the evolution of the system from the initial signal to its steady-state form. These experimental and numerical results illustrate the potential of the feedback process for use in narrow-band acoustical tomography.

  15. 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

  16. 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.

  17. Stochastic mirage phenomenon in a random medium.

    PubMed

    McDaniel, Austin; Mahalov, Alex

    2017-05-15

    In the framework of geometric optics, we consider the problem of characterizing the ray trajectory in a random medium with a mean refractive index gradient. Such a gradient results in the mirage phenomenon where an object's observed location is displaced from its actual location. We derive formulas for the mean ray path in both the situation of isotropic stochastic fluctuations and an important anisotropic case. For the isotropic model, the mean squared displacement is also given by a simple formula. Our results could be useful for applications involving the propagation of electromagnetic waves through the atmosphere, where larger-scale mean gradients and smaller-scale stochastic fluctuations are both present.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. Brugada phenocopy: A new electrocardiogram phenomenon

    PubMed Central

    Anselm, Daniel D; Evans, Jennifer M; Baranchuk, Adrian

    2014-01-01

    Brugada phenocopies (BrP) are clinical entities that are etiologically distinct from true congenital Brugada syndrome. BrP are characterized by type 1 or type 2 Brugada electrocardiogram (ECG) patterns in precordial leads V1-V3. However, BrP are elicited by various underlying clinical conditions such as myocardial ischemia, pulmonary embolism, electrolyte abnormalities, or poor ECG filters. Upon resolution of the inciting underlying pathological condition, the BrP ECG subsequently normalizes. To date, reports have documented BrP in the context of singular clinical events. More recently, recurrent BrP has been demonstrated in the context of recurrent hypokalemia. This demonstrates clinical reproducibility, thereby advancing the concept of this new ECG phenomenon. The key to further understanding the pathophysiological mechanisms behind BrP requires experimental model validation in which these phenomena are reproduced under strictly controlled environmental conditions. The development of these validation models will help us determine whether BrP are transient alterations of sodium channels that are not reproducible with a sodium channel provocative test or alternatively, a malfunction of other ion channels. In this editorial, we discuss the conceptual emergence of BrP as a new ECG phenomenon, review the progress made to date and identify opportunities for further investigation. In addition, we also encourage investigators that are currently reporting on these cases to use the term BrP in order to facilitate literature searches and to help establish this emerging concept. PMID:24669289

  5. Brugada phenocopy: A new electrocardiogram phenomenon.

    PubMed

    Anselm, Daniel D; Evans, Jennifer M; Baranchuk, Adrian

    2014-03-26

    Brugada phenocopies (BrP) are clinical entities that are etiologically distinct from true congenital Brugada syndrome. BrP are characterized by type 1 or type 2 Brugada electrocardiogram (ECG) patterns in precordial leads V1-V3. However, BrP are elicited by various underlying clinical conditions such as myocardial ischemia, pulmonary embolism, electrolyte abnormalities, or poor ECG filters. Upon resolution of the inciting underlying pathological condition, the BrP ECG subsequently normalizes. To date, reports have documented BrP in the context of singular clinical events. More recently, recurrent BrP has been demonstrated in the context of recurrent hypokalemia. This demonstrates clinical reproducibility, thereby advancing the concept of this new ECG phenomenon. The key to further understanding the pathophysiological mechanisms behind BrP requires experimental model validation in which these phenomena are reproduced under strictly controlled environmental conditions. The development of these validation models will help us determine whether BrP are transient alterations of sodium channels that are not reproducible with a sodium channel provocative test or alternatively, a malfunction of other ion channels. In this editorial, we discuss the conceptual emergence of BrP as a new ECG phenomenon, review the progress made to date and identify opportunities for further investigation. In addition, we also encourage investigators that are currently reporting on these cases to use the term BrP in order to facilitate literature searches and to help establish this emerging concept.

  6. 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

  7. 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.

  8. 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.

  9. [Dynamic wallpaper phenomenon and fusional hysteresis].

    PubMed

    Kondo, M; Nakamizo, S

    1982-12-01

    Two experiments were conducted with six and three subjects, respectively, to examine the "dynamic" wallpaper phenomenon in which the apparent location of a uniform repeating pattern shifted abruptly at a certain convergence distance when the pattern was viewed with the gradual change of convergence. Experiment 1 demonstrated that the critical convergence distances (shift points), at which the apparent location of the pattern shifted, differed between the two directions of the change of convergence, converging and diverging. It was greater in the diverging condition than in the converging condition. This fact shows a tendency to keep the same fusional state as far as possible when the convergence changes gradually. Experiment 2 showed that the difference of the critical convergence distance between the converging and diverging conditions is systematically related to the convergence level, that is, the difference increased as the convergence angle increased. The implications of the results of the two experiments were discussed in the context of the fusional hysteresis.

  10. The Phenomenon of the Urban Mummy.

    PubMed

    Harding, Brett E; Wolf, Barbara C

    2015-11-01

    The environmental mummification of a body in an urban setting is an unusual event. Florida is known for its high temperatures and humidity, which typically result in the rapid putrefaction of bodies. However, under certain circumstances, Florida's climate provides an environment suitable for mummification, typically in isolated areas. We previously reported a case of a homicide/suicide in a residential neighborhood in which the mummified remains were undetected for several years. We have subsequently encountered two additional cases in which mummified bodies were discovered in urban settings. Presented in the historical context of the environmental conditions and postmortem processes involved in mummification, these cases illustrate the particular constellation of human behaviors and scenarios, as well as environmental conditions, which must coincide for this phenomenon to occur and highlight the necessity of the multidisciplinary approach to the medicolegal investigation of such deaths and the determination of the cause and manner of death. © 2015 American Academy of Forensic Sciences.

  11. [Electroencephalographic characteristics of the deja vu phenomenon].

    PubMed

    Vlasov, P N; Cherviakov, A V; Gnezdinsiĭ, V V

    2013-01-01

    Déjà vu (DV, from French "already seen") is an aberration of psychic activity associated with transitory erroneous perception of novel circumstances, objects, or people as already known. An aim of the study was to investigate EEG characteristics of DV in patients with epilepsy. We studied 166 people (63.2% women, mean age 25.17±9.19 years). The DV phenomenon was studied in patients (27 people) and in a control group (139 healthy people). Patients were interviewed for DV characteristics and underwent a long (12-16 h) ambulatory EEG-monitoring study. In EEG, DV episodes in patients began with polyspike activity in the right temporal lobe and, in some cases, ended with the slow-wave theta-delta activity in the right hemisphere.

  12. 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.

  13. Bioelectrographic correlates of the direct vision phenomenon.

    PubMed

    Korotkov, Konstantin G; Bundzen, Pavel V; Bronnikov, Vjacheslav M; Lognikova, Lubov U

    2005-10-01

    A method for training children and adults to perceive visual information without using the eyes has been developed. A study was conducted to investigate the correlation of this perceptual capacity, known as direct vision (DV), with bioelectrographic measurements. Using the technique of dynamic digital gas-discharge visualization (GDV) bioelectrography, seven subjects were tested on three occasions over a 7-month period while they were in the process of reading information from a computer screen and reading printed text; this testing was repeated after an interval of 2 years. In multiple trials it was found that with the perception of information by DV, curves of GDV versus time exhibited specific dynamics, confirming the phenomenon of DV. At least three types of GDV characteristics can be distinguished in this state. This study also identified improvements in the psychosomatic state of children during the 7-month course of training in DV. The phenomenon of DV presents a newly recognized type of human information processing. It is based on a specific type of mental training that is statistically reproducible and has been assimilated by hundreds of children in Russia who are blind or have poor vision. The discovery of DV opens new perspectives in the study of the mechanisms of consciousness. The GDV characteristics that were observed during the perception of information by DV support the hypothesis that DV occurs through signals within the visible range of the electromagnetic spectrum. These results allow the proposal of a hypothesis for the way in which the brain, as well as the human system as a whole, registers information.

  14. The phenomenon of dynamic stall. [vortex shedding phenomenon on oscillating airfoils

    NASA Technical Reports Server (NTRS)

    Mccroskey, W. J.

    1981-01-01

    The general features of dynamic stall on oscillating airfoils are explained in terms of the vortex shedding phenomenon, and the important differences between static stall, light dynamic stall, and deep stall are described. An overview of experimentation and prediction techniques is given.

  15. [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

  16. 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.

  17. 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

  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. 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.

  20. 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

  1. [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.

  2. The microwave ultra-fast absorption phenomenon.

    NASA Astrophysics Data System (ADS)

    Chen, Xiaojuan; Ji, Shuchen

    A microwave ultra-fast absorption phenomenon observed with high time resolution on June 29, 1988 is analyzed. This absorption appeared at the atmospheric layer of 4.00 GHz above solar active region 5060 from 07h38m50s to 07h38m58sUT. At atmospheric layers of 2.84 GHz and 1.42 GHz spike emissions appeared. AR5060 was of the configuration of bipolar magnetic field which had strong activity. Hα flares of 3B and 2B were generated from 07h38m to 08h47mUT. X-ray burst of M6.5 also occurred. The authors have calculated the magnetic field of harmonic, S = 2, 3, at three frequencies (4.00 GHz, 2.84 GHz and 1.42 GHz) and analysed the absorption by using the bipolar field model. It is possible that the third harmonic of ECM at frequency of 4.00 GHz, was absorbed when it passed the absorption region.

  3. Doctor shopping: a phenomenon of many themes.

    PubMed

    Sansone, Randy A; Sansone, Lori A

    2012-11-01

    Doctor shopping is defined as seeing multiple treatment providers, either during a single illness episode or to procure prescription medications illicitly. According to the available literature, prevalence rates of doctor shopping vary widely, from 6.3 to 56 percent. However, this variability is partially attributable to research methodology, including the study definition of doctor shopping as well as the patient sample. The reasons for doctor shopping are varied. Some patient explanations for this phenomenon relate to clinician factors, such as inconvenient office hours or locations, long waiting times, personal characteristics or qualities of the provider, and/or insufficient communication time between the patient and clinician. Some patient explanations relate to personal factors and include both illness factors (e.g., symptom persistence, lack of understanding or nonacceptance of the diagnosis or treatment) as well as psychological factors (e.g., somatization, prescription drug-seeking). Importantly, not all doctor shopping is driven by suspect motivations. Being aware of these various patient justifications for doctor shopping is important in understanding and managing these challenging patients in the clinical setting, whether they emerge in psychiatric or primary care environments.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Is there an obstetric July phenomenon?

    PubMed

    Myles, Thomas D

    2003-11-01

    To estimate whether variations in intrapartum management and complications exist with regard to the time of delivery within the academic year. The delivery records of 7814 patients were separated by both term half year and quarter. Statistical comparisons were made using chi2 tests of association (P < .05) with respect to the academic time of the year and perineal trauma (third- or fourth-degree tear), episiotomy usage, cesarean delivery, postpartum hemorrhage, chorioamnionitis, shoulder dystocia, neonatal intensive care unit admission, 1- or 5-minute Apgar scores less than 7, and low umbilical cord pH. There were 4082 deliveries in the first half and 3732 in the second half of the year from April 1996 through March 1999. The first half-year overall cesarean rate was higher (15.8% versus 14.3%, P < .03). Primary cesarean rates were similar. No other differences were found by term half year. More perineal trauma was noted in the fourth quarter (first 3.3%, second 4.5%, third 3.7%, fourth 5.5%, P < .037). Episiotomy usage was higher in both the first and fourth quarters (13.0%, 11.3%, 10.6%, and 14.8%, P < .002). More cases of chorioamnionitis occurred in the fourth quarter (first 3.4%, second 3.1%, third 2.6%, fourth 4.0%, P < .038, third versus fourth quarter). Chorioamnionitis occurred more frequently in July (July 5.0% versus August-June 3.1%, P < .005). There were no other clinically significant differences. Neonatal outcomes were not affected by academic time of year. Although small differences in outcome exist with respect to the academic time of the year, the timing of these differences indicates that there is not a "July phenomenon" in obstetrics at our institution.

  10. 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

  11. The Trump phenomenon: An explanation from sociophysics

    NASA Astrophysics Data System (ADS)

    Galam, Serge

    2017-04-01

    The Trump phenomenon is argued to depart from current populist rise in Europe. According to a model of opinion dynamics from sociophysics the machinery of Trump’s amazing success obeys well-defined counter-intuitive rules. Therefore, his success was in principle predictable from the start. The model uses local majority rule arguments and obeys a threshold dynamics. The associated tipping points are found to depend on the leading collective beliefs, cognitive biases and prejudices of the social group which undertakes the public debate. And here comes the open sesame of the Trump campaign, which develops along two successive steps. During a first moment, Trump’s statement produces a majority of voters against him. But at the same time, according to the model the shocking character of the statement modifies the prejudice balance. In case the prejudice is present even being frozen among voters, the tipping point is lowered at Trump’s benefit. Nevertheless, although the tipping point has been lowered by the activation of frozen prejudices it is instrumental to preserve enough support from openly prejudiced people to be above the threshold. Then, as infuriated voters launch intense debate, occurrence of ties will drive progressively hostile people to shift their voting intention without needing to endorse the statement which has infuriated them. The ongoing debate does drive towards a majority for Trump. The possible Trump victory at November Presidential election is discussed. In particular, the model shows that to eventually win the Presidential election, Trump must not modify his past shocking attitude but to appeal to a different spectrum of frozen prejudices, which are common to both Democrats and Republicans.

  12. Weight-based discrimination: an ubiquitary phenomenon?

    PubMed

    Sikorski, C; Spahlholz, J; Hartlev, M; Riedel-Heller, S G

    2016-02-01

    Despite strong indications of a high prevalence of weight-related stigmatization in individuals with obesity, limited attention has been given to the role of weight discrimination in examining the stigma obesity. Studies, up to date, rely on a limited basis of data sets and additional studies are needed to confirm the findings of previous studies. In particular, data for Europe are lacking, and are needed in light of a recent ruling of the European Court of Justice that addressed weight-based discrimination. The data were derived from a large representative telephone survey in Germany (n=3003). The dependent variable, weight-based discrimination, was assessed with a one-item question. The lifetime prevalence of weight discrimination across different sociodemographic variables was determined. Logistic regression models were used to assess the association of independent and dependent variables. A sub-group analysis was conducted analyzing all participants with a body mass index ⩾25 kg m(-)(2). The overall prevalence of weight-based discrimination was 7.3%. Large differences, however, were observed regarding weight status. In normal weight and overweight participants the prevalence was 5.6%, but this number doubled in participants with obesity class I (10.2%), and quadrupled in participants with obesity class II (18.7%) and underweight (19.7%). In participants with obesity class III, every third participant reported accounts of weight-based discrimination (38%). In regression models, after adjustment, the associations of weight status and female gender (odds ratio: 2.59, P<0.001) remained highly significant. Discrimination seems to be an ubiquitary phenomenon at least for some groups that are at special risk, such as heavier individuals and women. Our findings therefore emphasize the need for research and intervention on weight discrimination among adults with obesity, including anti-discrimination legislation.

  13. Hysteresis phenomenon in the dynamics of spiral waves rotating around a hole

    NASA Astrophysics Data System (ADS)

    Zykov, V.; Bordyugov, G.; Lentz, H.; Engel, H.

    2010-06-01

    Hysteresis in the pinning-depinning transitions of spiral waves rotating around a hole in a circular shaped two-dimensional excitable medium is studied both by use of the continuation software AUTO and by direct numerical integration of the reaction-diffusion equations for the FitzHugh-Nagumo model. In order to clarify the role of different factors in this phenomenon, a kinematical description is applied. It is found that the hysteresis phenomenon computed for the reaction-diffusion model can be reproduced qualitatively only when a nonlinear eikonal equation (i.e. velocity-curvature relationship) is assumed. However, to obtain quantitative agreement, the dispersion relation has to be taken into account.

  14. 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

  15. 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

  16. 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.

  17. Recent achievements in the management of Raynaud’s phenomenon

    PubMed Central

    Baumhäkel, Magnus; Böhm, Michael

    2010-01-01

    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. PMID:20407628

  18. 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.

  19. 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.

  20. 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

  1. 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…

  2. 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…

  3. 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.

  4. The "Testing" Phenomenon: Not Gone but Nearly Forgotten.

    ERIC Educational Resources Information Center

    Glover, John A.

    1989-01-01

    Four experiments with 263 undergraduates and 57 seventh-graders examined the "testing phenomenon" in relation to students' memory for brief passages and labels for parts of flowers. The phenomenon, which involves the positive effects of previous testing on final test performance, appears to depend on several complete retrieval events. (TJH)

  5. 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…

  6. Severe Raynaud's phenomenon with yohimbine therapy for erectile dysfunction.

    PubMed

    Johnson, Sindhu; Iazzetta, John; Dewar, Catharine

    2003-11-01

    Yohimbine is a selective alpha-2 adrenergic antagonist that has been used in the pharmacologic management of erectile dysfunction (ED). We describe a patient with CREST syndrome (calcinosis, Raynaud's phenomenon, esophageal dysfunction, sclerodactyly, and telangiectasia) who paradoxically experienced worsening of Raynaud's phenomenon when using yohimbine for ED.

  7. 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.

  8. The validity of Raynaud's phenomenon symptoms in HAVS cases.

    PubMed

    Youakim, Sami

    2008-09-01

    Raynaud's phenomenon, a common manifestation of the hand-arm vibration syndrome (HAVS), is typically diagnosed by a subjective history provided by employees. This study evaluates the validity of the subjective history of Raynaud's phenomenon provided by individuals applying for compensation for HAVS. Thirty-six workers with a history of occupational hand-arm vibration exposure who were labelled as having Raynaud's phenomenon were asked to photographically document their finger symptoms before undergoing a detailed clinical assessment. Each individual was provided with a disposable camera and instructions. Returned photographs were reviewed for signs of Raynaud's phenomenon. The reliability of photograph interpretation was tested with three physicians and a non-physician. Inter and intra-rater reliability was very good, Kappa coefficient >0.80. Six individuals (17%) did not return cameras. Thirty individuals provided photographs and underwent a clinical evaluation. The photographs of 13 individuals (43%) did not show Raynaud's phenomenon and for four of these the diagnosis was not supported by careful symptom history. Seventeen individuals (57%) had photographic evidence of Raynaud's phenomenon. A presenting history of Raynaud's phenomenon in workers seeking compensation for HAVS may not be accurate since approximately half the cases are unable to provide objective photographic evidence of Raynaud's phenomenon.

  9. 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.

  10. [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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Large-scale sodium-basalt concrete reaction test LSC-1

    SciTech Connect

    McCormick, M.W.; Muhlestein, L.D.; Colburn, R.P.; Winkel, B.V.

    1981-06-01

    The energy and hydrogen released from sodium-concrete reactions must be considered the analysis of beyond-design basis accidents for breeder reactors. Consequently, a large-scale sodium-basalt concrete reaction test was completed in the Large Sodium Fire Facility (LSFF) at the Hanford Engineering Development Laboratory (HEDL). 454 kg of sodium at 593{sup 0}C was spilled onto 0.84 m{sup 2} of basalt concrete 0.61 m deep containing two layers of reinforcing steel bar. From the data obtained, it was possible to complete a mass and energy balance for this test. The hydrogen generation and generation rate as functions of time for the duration of the test were determined. The major contribution to the chemical energy was energy associated with the formation of hydrogen (sodium-water reactions).

  17. Inverse Bell's Phenomenon: Rare Ophthalmic Finding Following Ptosis Surgery.

    PubMed

    Shitole, Satish; Jakkal, Tapan; Khaire, Bhasakar

    2015-03-01

    Bell's phenomenon is protective reflex in which the globe is turned upwards and slightly outwards during the eyelid closure to avoid corneal exposure. In Inverse Bell's phenomenon, the eye moves downward instead of upward, this may be seen in the normal population, patients with Bell's palsy or following conjunctival scarring. We hereby present the unusual complication of transient inversion of Bell's phenomenon following extensive levator resection surgery performed for congenital ptosis. A 24-year-old male was undergone ptosis correction surgery. On postoperative day two, ocular examination revealed down rolling of eye ball during eyelid closure. It underwent spontaneous resolution within four weeks without any corneal complication. The patients were given frequent lubricating eye drops during this period and advised frequent follow-up for early diagnosis of corneal complication. Here we highlight an inverse Bell's phenomenon following levator resection surgery, its possible mechanism and risk of corneal complication.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Professor Nambu, string theory, and the moonshine phenomenon

    NASA Astrophysics Data System (ADS)

    Eguchi, Tohru

    2016-11-01

    I first recall the last occasion I met the late Professor Yoichiro Nambu, in a hospital in Osaka. I then present a brief introduction to a moonshine phenomenon in string theory that have recently come under investigation.

  3. Symptomatic Epidural Gas-containing Cyst from Intervertebral Vacuum Phenomenon.

    PubMed

    Yun, Sung Min; Suh, Bumn Suk; Park, Jin Su

    2012-12-01

    Vacuum disc phenomenon is a collection of gas in the intervertebral disc space but rarely causes nerve compression. However, some rare type of vacuum phenomenon in the spinal canal may bring about posterior gas displacement within the epidural space. The authors describe two patients with symptomatic epidural gas-containing cyst that seem to be originating from vacuum phenomenon in the intervertebral disc, causing lumbosacral radiculopathy. Radiographic studies demonstrated intervertebral vacuum phenomenon and accumulation of gas in the lumbar epidural space compressing the dural sac and the nerve root. The nerve root in both patients was compressed by gas containing cyst that was surrounded by thin walled capsule separable from the gaseous degenerated disc space. The speculative mechanism of the nerve root compression is discussed. The possibility of gas containing cyst should be considered in case of the nerve root compression in which epidural gas is present.

  4. Benign "setting sun" phenomenon in full-term infants.

    PubMed

    Yoshikawa, Hideto

    2003-06-01

    I report two normally developed infants showing benign" setting sun" phenomenon. A 2(2-12)-year-old boy and a 7-year-old boy, who were born without any complications at full term, developed brief episodes of downward gazing during sucking and crying after birth However, there were no other clinical or laboratory findings, and they developed normally. The phenomenon was not visible until 6 months and 7 months, respectively. The "setting sun" phenomenon usually indicates underlying severe brain damage and can also be seen, although rarely, in healthy full-term infants until 1 to 5 months. However, the benign "setting sun" phenomenon might exist until 6 or 7 months of age in normal infants.

  5. Rumpel-Leede phenomenon presenting as a hypertensive urgency

    PubMed Central

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

    2016-01-01

    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. PMID:27034570

  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: A Case Report.

    PubMed

    Cheok, Liang Jie; Ooi, Chee Kheong

    2017-06-01

    Raynaud's phenomenon has multiple etiologies, ranging from occupational causes to systemic disease. Most occupational causes of Raynaud's phenomenon usually present with vascular compromise. A 41-year-old Chinese woman presented to the emergency department with progressive pain and bluish discoloration over her right index finger after minor trauma. The clinical examination revealed discoloration over multiple fingertips on both hands. She was diagnosed with Raynaud's phenomenon with possible underlying systemic disease. Additional laboratory workup led to the diagnosis of systemic lupus erythematosus with complex regional pain syndrome. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: It is rare for the emergency physician to diagnose Raynaud's phenomenon in the setting of minor trauma. It is important to diagnose this condition because of its potential complications. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Drug Reactions

    MedlinePlus

    ... or diabetes. But medicines can also cause unwanted reactions. One problem is interactions, which may occur between ... more serious. Drug allergies are another type of reaction. They can be mild or life-threatening. Skin ...

  9. 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.

  10. 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

  11. [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.

  12. Osteitis condensans illii — a sacrolliac stress phenomenon: a report of a case

    PubMed Central

    Nykoliation, J. W.; Cassidy, J. D.; Dupuis, P.

    1984-01-01

    Osteitis condensans illii (O.C.I.) is a radiographic finding characterized by a triangular area of sclerosis in the iliac portion of the sacroiliac joint. Current literature views the phenomenon as a stress-related sclerotic reaction in the peri-articular bone. It is possible that O.C.I. represents an advanced form of degenerative arthrosis of the fibrocartilage along the iliac portion of the sacroiliac joint. O.C.I. is not believed to be a pain-producing entity, but may be associated with sacroiliac syndrome. A case is presented illustrating the successful treatment by chiropractic manipulation. ImagesFigure 1Figure 2

  13. [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.

  14. 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

  15. 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.

  16. Emperipolesis: An Unreported Novel Phenomenon in Oral Squamous Cell Carcinoma.

    PubMed

    Sarode, Gargi S; Sarode, Sachin C; Patil, Shankargouda

    2017-04-01

    Emperipolesis is a phenomenon characterized by engulfment of hematopoietic cells by megakaryocytes, monocytes, fibroblasts, and malignant cells within their cytoplasm. This phenomenon has been reported in various physiological and pathological conditions including malignancies. However, emperipolesis has never been reported in oral squamous cell carcinoma (OSCC) till date. We have analyzed histopathological slides of 56 cases of OSCC to see lymphocyte engulfment by tumor cells. Five cases showing features of this phenomenon were observed. Lymphocytes were typically identified as small round cells with oval nuclei and scanty cytoplasm. Both partial and complete engulfment of lymphocytes by tumor cells was appreciated. Nuclei of the host tumor cells were crescent shaped and illustrated small concave indentation, so as to accommodate the internalized lymphocyte. The intercellular bridges were not seen between the internalized cell and the host cell. There were no signs of degeneration appreciable in either cell, thus ruling out the possibility of cannibalism phenomenon. Although emperipolesis is a well-known phenomenon in pathology, this is the first report showing its evidence in OSCC.

  17. 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.

  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. Self-Propelled Hovercraft Based on Cold Leidenfrost Phenomenon.

    PubMed

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

    2016-06-24

    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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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

  8. Kasabach-Merritt Phenomenon: Classic Presentation and Management Options.

    PubMed

    Mahajan, Priya; Margolin, Judith; Iacobas, Ionela

    2017-01-01

    Kasabach-Merritt phenomenon (KMP) is a rare consumptive coagulopathy associated with specific vascular tumors, kaposiform hemangioendothelioma, and tufted angioma. Kasabach-Merritt phenomenon, characterized by profound thrombocytopenia, hypofibrinogenemia, elevated fibrin split products, and rapid tumor growth, can be life-threatening. Severe symptomatic anemia may also be present. With prompt diagnosis and management, KMP can resolve and vascular tumors have been shown to regress. This review highlights the clinical presentation, histopathology, management, and treatment of KMP associated with kaposiform hemangioendothelioma, and less frequently tufted angioma. A classic clinical case is described to illustrate the presentation and our management of a patient with KMP.

  9. 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.

  10. [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.

  11. [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.

  12. 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.

  13. 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

  14. 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…

  15. Possible dynamical mechanisms for the Martian polar warming phenomenon

    NASA Technical Reports Server (NTRS)

    Barnes, Jeffrey R.

    1987-01-01

    The research performed under NASA contract NAGW-727 falls into three major categories, i.e., dynamical modeling of the Martian polar warming phenomenon, studies of dust and water transport associated with a Martian polar warming, and studies of the possible effects of breaking gravity waves on the Martian atmospheric circulation. The work carried out in each of these areas is summarized.

  16. 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…

  17. 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,…

  18. 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…

  19. 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.

  20. 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…

  1. 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…

  2. 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.

  3. 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.

  4. 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…

  5. 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"…

  6. 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)

  7. Examining the Spatial Ability Phenomenon from the Student's Perspective

    ERIC Educational Resources Information Center

    Mohler, J. L.

    2008-01-01

    This phenomenological investigation examined the lived experience of technically-oriented students over the course of a single semester, attempting to answer the question, "What was it like for a student to experience the spatial ability phenomenon?" The study included 12 interviewees and 8 focus group freshman participants at a Midwestern…

  8. 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…

  9. Gibbs' phenomenon for nonnegative compactly supported scaling vectors

    NASA Astrophysics Data System (ADS)

    Ruch, David K.; van Fleet, Patrick J.

    2005-04-01

    This paper considers Gibbs' phenomenon for scaling vectors in . We first show that a wide class of multiresolution analyses suffer from Gibbs' phenomenon. To deal with this problem, in [Contemp. Math. 216 (1998) 63-79], Walter and Shen use an Abel summation technique to construct a positive scaling function Pr, 0phenomenon. These results were extended to scaling vectors and multiwavelets in [Proceedings of Wavelet Analysis and Multiresolution Methods, 2000, pp. 317-339]. In both cases, orthogonality and compact support were lost in the construction process. In this paper we modify the approach given in [Proceedings of Wavelet Analysis and Multiresolution Methods, 2000, pp. 317-339] to construct compactly supported positive scaling vectors. While the mapping into V0 associated with this new positive scaling vector is not a projection, the scaling vector does produce a Riesz basis for V0 and we conclude the paper by illustrating that expansions of functions via positive scaling vectors exhibit no Gibbs' phenomenon.

  10. 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)

  11. Echo phenomenon associated with lower-hybrid-wave launching

    SciTech Connect

    Wong, K.L.; Skiff, F.; Ono, M.

    1983-06-01

    Lower hybrid waves at two different frequencies f/sub 1/ and f/sub 2/ are launched simultaneously from two localized antennas, and a third wave is observed to arise near the plasma edge at the frequency f = f/sub 2/ - f/sub 1/. This phenomenon can be explained by an echo effect near the plasma surface.

  12. Coronary Slow Flow Phenomenon Leads to ST Elevation Myocardial Infarction.

    PubMed

    Sen, Taner

    2013-03-01

    The exact etiology of the coronary slow flow phenomenon (CSFP) is not certain. CSFP is not a normal variant as it is an absolutely pathological entity. Furthermore, CSFP not only leads to myocardial ischemia but it can also cause classical acute ST elevation myocardial infarction, which necessitates coronary angiography for a definite diagnosis.

  13. 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"…

  14. Educationally Resilient Adolescents' Implicit Knowledge of the Resilience Phenomenon.

    ERIC Educational Resources Information Center

    Rouse, Kimberly A. Gordon; Bamaca-Gomez, Mayra Y.; Newman, Phil; Newman, Barbara

    For many years, the resilience phenomenon in populations at-risk has been a major focus in trying to understand and explain why some people who experience challenging and stressful experiences are able to overcome these negative adversities and adapt competently. Resilience has been found to consist of different protective factors that are…

  15. 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…

  16. 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

  17. Glow phenomenon surrounding the vertical stabilizer and OMS pods

    NASA Image and Video Library

    1994-03-05

    STS062-42-026 (4-18 March 1994) --- 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.

  18. 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…

  19. 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…

  20. 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)

  1. Judging Attraction from Nonverbal Behavior: The Gain Phenomenon

    ERIC Educational Resources Information Center

    Clore, Gerald L.; And Others

    1975-01-01

    Describes two experiments conducted to explore non-verbal behaviors and their capacity to convey attraction between men and women. Examines in particular the gain phenomenon which is the idea that people are more attracted to a person who is initially punishing and then rewarding than to one who is always rewarding. (Author/EJT)

  2. 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.

  3. The Critical Vulnerability of Technological Dependence: A Culturally Driven Phenomenon

    DTIC Science & Technology

    2014-05-22

    completes-u- s -navy-aircraft- satcom-demonstration-2/ (accessed October 24, 2013). Hofstede , Geert and Gert Jan Hofstede . Cultures and...33Geert Hofstede and Gert Jan Hofstede , Cultures and Organizations: Software of the Mind, (New York: McGraw...Approved for Public Release; Distribution is Unlimited THE CRITICAL VULNERABILITY OF TECHNOLOGICAL DEPENDENCE: A CULTURALLY DRIVEN PHENOMENON A

  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. [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.

  6. Vestibular hypersensitivity to sound (Tullio phenomenon): structural and functional assessment.

    PubMed

    Watson, S R; Halmagyi, G M; Colebatch, J G

    2000-02-08

    To establish the role of high-resolution CT imaging and tests of vestibulocollic reflexes in diagnosing and understanding the pathogenesis of the Tullio phenomenon. The Tullio phenomenon is a syndrome in which acoustic stimulation produces symptoms and signs of vestibular activation. It has previously been associated with an abnormally low threshold for click-evoked vestibulocollic responses and also with dehiscence of the roof of the anterior (superior) semicircular canal on high-resolution CT scans of the temporal bones. High-resolution CT scans of the temporal bones and vestibulocollic responses in sternocleidomastoid to both clicks and transmastoid galvanic stimulation (3 mA/2 msec) were studied in four patients with the Tullio phenomenon (one bilateral). Click-evoked thresholds were low for all affected ears (four at 65 dB nHL, one at 55 dB nHL) and normal (>70 dB nHL) for the three unaffected ears. In contrast, galvanic-evoked vestibulocollic responses were symmetric and of normal size in all patients. The bony roof of the anterior (superior) semicircular canal was thin, possibly absent, on CT of all affected ears and also in two out of three unaffected ears. The normal galvanic vestibulocollic responses indicate that sound sensitivity in patients with the Tullio phenomenon is likely to occur distal to the vestibular nerve, probably at the level of the receptors. Both click hypersensitivity and dehiscence of the anterior (superior) semicircular canal are associated with the Tullio phenomenon but as the CT scan abnormality can occur in clinically unaffected ears, click testing is important for specific diagnosis. Abnormal sound sensitivity, as demonstrated by click responses, confirms that the radiologic abnormality is function significant.

  7. Hydrogen triggered exothermal reaction in uranium metal

    NASA Astrophysics Data System (ADS)

    Dufour, J.; Murat, D.; Dufour, X.; Foos, J.

    2000-06-01

    An exothermal reaction has been observed when submitting metallic uranium to the combined action of a magnetic field and an electrical current. The set-up used to study the phenomenon is described and results are given. A tentative explanation is given, based on the possible existence of a still hypothetical proton/electron resonance.

  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. Earthquake source parameters that display the first digit phenomenon

    NASA Astrophysics Data System (ADS)

    Toledo, P. A.; Riquelme, S. R.; Campos, J. A.

    2015-10-01

    We study the main parameters of earthquakes from the perspective of the first digit phenomenon: the nonuniform probability of the lower first digit different from 0 compared to the higher ones. We found that source parameters like coseismic slip distributions at the fault and coseismic inland displacements show first digit anomaly. We also found the tsunami runups measured after the earthquake to display the phenomenon. Other parameters found to obey first digit anomaly are related to the aftershocks: we show that seismic moment liberation and seismic waiting times also display an anomaly. We explain this finding by invoking a self-organized criticality framework. We demonstrate that critically organized automata show the first digit signature and we interpret this as a possible explanation of the behavior of the studied parameters of the Tohoku earthquake.

  10. Earthquake source parameters which display first digit phenomenon

    NASA Astrophysics Data System (ADS)

    Toledo, P. A.; Riquelme, S. R.; Campos, J. A.

    2015-05-01

    We study main parameters of earthquakes from the perspective of the first digit phenomenon: the nonuniform probability of the lower first digit different from zero compared to the higher ones. We found that source parameters like coseismic slip distributions at the fault and coseismic inland displacements show first digit anomaly. We also found the tsunami runups measured after the earthquake to display the phenomenon. Other parameters found to obey first digit anomaly are related to the aftershocks: we show that seismic moment liberation and seismic waiting times also display an anomaly. We explain this finding by invoking a self-organized criticality frame. We show that critically organized automata show the first digit signature and we interpret this as a possible explanation of the behavior of the studied parameters of the Tohoku earthquake.

  11. 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.

  12. 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

  13. 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.

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

    PubMed

    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.

  15. Control of dynamic stall phenomenon for vertical axis wind turbine

    NASA Astrophysics Data System (ADS)

    Frunzulicǎ, Florin; Dumitrescu, Horia; Dumitrache, Alexandru; Suatean, Bogdan

    2013-10-01

    In the last years the wind turbine with vertical axis (VAWT) began to be more attractive due benefits in exploitation, the power range covering usually the domain 2 kW-20 kW. But, VAWTs suffer from many complicated aerodynamically problems, of which dynamic stall is an inherent phenomenon when they are operating at low values of tip speed ratio (TSR < 4), and this has a significant impact on vibration, noise, and power output of the VAWTs. For this reason, in the present work we perform a computational investigation of a two-dimensional dynamic stall phenomenon around a NACA0012 airfoil in oscillating motion at relative low Reynolds number (˜105). The unsteady flow is investigated numerically using RANS approach with two turbulence models (k-ω SST and transition SST). The same analysis was performed to evaluate three flow control methods: two passive and one active.

  16. Understanding the alternate bearing phenomenon: Resource budget model.

    PubMed

    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.

  17. 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

  18. 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.

  19. Spontaneous Intra-Parenchymal Rupture of Craniopharyngioma - A Rare Phenomenon.

    PubMed

    Rajan, Vivakaran Thanga Tirupathi; Janani, Asogan Vaishnavi; Kumar, Aiyappan Senthil; Sundar, Ilangovan Vijay

    2017-07-01

    Craniopharyngioma is a relatively benign intracranial tumour that involves sellar and supra-sellar regions. Spontaneous rupture of craniopharyngioma into the sub-arachnoid space or into the ventricles is a rare phenomenon and few cases are reported in literature. We hereby report a case of sellar-suprasellar craniopharyngioma with focal intra-parenchymal rupture into brain causing aggravation of headache in a 12-year-old female child. This complication is a relatively rare phenomenon, which requires attention for early intervention. This was managed by trans-nasal endoscopic trans-sphenoidal surgery. Usually rupture of craniopharyngioma causes chemical meningitis or it can be asymptomatic. Sometimes rupture can cause complete resolution of cyst and symptoms. In the present case, there was only focal rupture and it was into brain parenchyma causing brain oedema with aggravation of headache. Magnetic Resonance Imaging (MRI) in intra-parenchymal rupture of craniopharyngioma has been emphasized in this case report.

  20. 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.

  1. STUDIES ON THE MECHANISM OF THE SHWARTZMAN PHENOMENON

    PubMed Central

    Stetson, Chandler A.

    1951-01-01

    Evidence is presented to indicate that a profound thrombocytopenia and granulocytopenia occur during the second stage of the Shwartzman phenomenon, prior to the actual onset of hemorrhage in the prepared skin areas. These hematologic alterations appear to be due to accumulation of the cells mentioned in the capillary bed of the lungs and perhaps other internal organs. This seems to be consequent on certain changes in the platelets and polymorphonuclear leucocytes, which result in the formation of clumps of these elements. In skin areas prepared for the Shwartzman phenomenon, the capillaries and small veins become occluded by masses of platelets and granulocytes after the intravenous challenging injection has been given. Following the interruption of blood supply necrosis of the involved vessels takes place, and hemorrhage occurs later where the vessel walls have lost their integrity. PMID:14832396

  2. 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.

  3. Dream screen phenomenon in psychotherapy and artistic work.

    PubMed

    Saarinen, Pirjo Irmeli

    2003-01-01

    The aim of this article is to offer a point on the meaning of the dream screen phenomenon in psychotherapy and artistic work. Some current theories of early ego development, the formation of the dream screen and dream imagery seem to match the theories of symbol formation, artistic and literary creativity. In actual dreaming, the dream screen can exist in the form of empty sheets of paper, but also in the form of a landscape, hills or mountains. The activation of the dream screen is presented in the light of the psychotherapy of two depressed patients. Dreams implying activation of the dream screen have been interpreted to signify a turning point during psychotherapy. Dream screen can be considered as a phenomenon with different elements. Examples of dream screen symbols in Aleksis Kivi's poems and in Paul Cézanne's paintings are presented.

  4. Use of Unlabeled Samples for Mitigating the Hughes Phenomenon

    NASA Technical Reports Server (NTRS)

    Landgrebe, David A.; Shahshahani, Behzad M.

    1993-01-01

    The use of unlabeled samples in improving the performance of classifiers is studied. When the number of training samples is fixed and small, additional feature measurements may reduce the performance of a statistical classifier. It is shown that by using unlabeled samples, estimates of the parameters can be improved and therefore this phenomenon may be mitigated. Various methods for using unlabeled samples are reviewed and experimental results are provided.

  5. 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}.

  6. 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

  7. 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.

  8. 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

  9. 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

  10. [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.

  11. Tullio phenomenon with dehiscence of the superior semicircular canal.

    PubMed

    Ostrowski, V B; Byskosh, A; Hain, T C

    2001-01-01

    The goal of the investigation was to determine if vector analysis of nystagmus in a patient with the Tullio phenomenon could determine the source of the nystagmus. The Tullio phenomenon consists of the combination of vertigo and abnormal eye and/or head movements provoked by sound. Dehiscence of the superior semicircular canal can be found in certain patients with the Tullio phenomenon. The patient was tested with pure tones ranging from 250 to 3,000 Hz at 95dB HL. The time course of the three-dimensional vector of eye movement, including torsion and vertical and horizontal displacement angles was determined by individual stop-frame analysis of digitized video. Torsion amplitude varied from 1 to 7 degrees; vertical amplitude varied from 1 to 5 degrees; and horizontal amplitude varied less than 1.5 degrees. The maximal response occurred on stimulation of the right ear with a 1,250-Hz 95-dB HL tone. This elicited a reliable counterclockwise torsional and down-beating fast phase nystagmus as seen from the examiner's point of view. Comparison of the nystagmus with known canal vectors identified the right superior semicircular canal as the source of stimulation. High-resolution computed tomography scan of the temporal bone showed a definite right superior canal dehiscence. The origin of nystagmus from the Tullio phenomenon can be identified by calculating the three-dimensional vector of the observed nystagmus. We show that vector analysis of the observed eye movement can be used to infer the source of nystagmus in these patients. The development of real-time, three-dimensional vector analysis of nystagmus is desirable.

  12. 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.

  13. Rumpel-Leede Phenomenon in a Hypertensive Lady on Amlodipine

    PubMed Central

    Viswanathan, Stalin

    2014-01-01

    We are describing a 60-year-old hypertensive lady who developed Rumpel-Leede phenomenon following the use of a tourniquet to obtain a blood sample. History revealed that she was on amlodipine therapy and that spontaneous sun-exposure related purpura was often seen since amlodipine was prescribed. Examinations and investigations provided normal results. She refused consent for a skin biopsy. Symptoms resolved after its substitution with enalapril and dihydrochlorothiazide, without any further recurrence. PMID:24959504

  14. Simulation of Hydrodynamic Ram Phenomenon Using MSC Dytran

    DTIC Science & Technology

    2014-09-01

    MASTER OF SCIENCE IN MECHANICAL ENGINEERING from the NAVAL POSTGRADUATE SCHOOL September 2014 Author: Kangjie Roy Yang Approved by...phenomenon has led to extensive efforts in developing numerical techniques for computational simulation. Such efforts had been attempted for the past... computational power might be a potential downside. Moreover, no validation to the numerical model was performed, due to the lack of experimental data [1

  15. 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.

  16. 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.

  17. Exploration of the e-patient phenomenon in nursing informatics.

    PubMed

    Gee, Perry M; Greenwood, Deborah A; Kim, Katherine K; Perez, Susan L; Staggers, Nancy; DeVon, Holli A

    2012-01-01

    The availability of health information on the Internet has equalized opportunities for knowledge between patients and their health care providers, creating a new phenomenon called the e-patient. E-patients use technology to actively participate in their health care and assume higher levels of responsibility for their own health and wellness. This phenomenon has implications for nursing informatics research related to e-patients and potential collaboration with practitioners in developing a collective wisdom. Nursing informatics can use the data, information, knowledge, and wisdom (DIKW) framework to understand how e-patients and clinicians may achieve this collective wisdom. Nurse informaticists can use constructivism and Gadamerian hermeneutics to bridge each stage of this framework to illustrate the fundamentals of patient and clinician interactions and commonality of language to achieve a collective wisdom. Examining the e-patient phenomenon will help nurse informaticists evaluate, design, develop, and determine the effectiveness of information systems used by e-patients. The Internet can facilitate a partnership between the patient and clinician and cultivate a collective wisdom, enhanced by collaboration between nurse informatics and e-patients. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. 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

  19. 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

  20. 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. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. 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?".

  2. Genetic View on the Phenomenon of Combined Diseases in Man

    PubMed Central

    Freidin, M.B.

    2009-01-01

    In clinical medicine, the phenomenon of polypathy, as a particular object of investigation, was first put forth by French clinicians at the end of the 19th century through the "arthritismus" doctrine. In the first half of the 20th century, German paediatricians singled out "syntropias," which are combinations of diseases with common pathophysiological mechanisms, and "dystropias," which are diseases that rarely co-occur in one individual. In the present paper, syntropy/dystropy is defined as a natural generic nonrandom phenomenon with an evolutionary-genetic basis. The genes involved in the development of syntropy are called "syntropic genes," whereas the genes that co-participate in pathophysiological mechanisms and prevent the co-occurrence of particular phenotypes are called "dystropic genes." Prospects for studying the genetic basis of this phenomenon are highlighted. The publicly available database HuGENet can be used in order to identify syntropic genes, as will be shown as examples in an analysis of cardiovascular diseases. PMID:22649614

  3. 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?"

  4. Black-spot poison ivy: a rare phenomenon.

    PubMed

    Paniagua, Carmen T; Bean, Ashley S

    2011-06-01

    To provide an overview of the clinical presentation, diagnosis, management, and treatment with advanced practice nursing implications of black-spot poison ivy phenomenon. Case presentation and comprehensive literature review on black-spot poison ivy. Black-spot poison ivy is a rare phenomenon and usually poses a diagnostic challenge. It usually presents after exposure to a higher concentration of uroshiol on Toxicodendron plants. Patients present with black-spot deposits on the epidermis with underlying poison ivy dermatitis. The black deposits cannot be washed off the skin and are followed by itchy blisters. They eventually peel off and the skin heals without scarring. An understanding of the pathophysiology, clinical presentation, treatment, and management of this rare phenomenon is important for the nurse practitioner (NP) to be able to make an accurate diagnosis and initiate appropriate treatment without delay. The NP's recognition and differentiation of it from other skin disorders including melanoma is paramount. ©2011 The Author(s) Journal compilation ©2011 American Academy of Nurse Practitioners.

  5. Identifying Mechanisms Behind the Tullio Phenomenon: a Computational Study Based on First Principles.

    PubMed

    Grieser, Bernhard J; Kleiser, Leonhard; Obrist, Dominik

    2016-04-01

    Patients with superior canal dehiscence (SCD) suffer from events of dizziness and vertigo in response to sound, also known as Tullio phenomenon (TP). The present work seeks to explain the fluid-dynamical mechanisms behind TP. In accordance with the so-called third window theory, we developed a computational model for the vestibular signal pathway between stapes and SCD. It is based on first principles and accounts for fluid-structure interactions arising between endolymph, perilymph, and membranous labyrinth. The simulation results reveal a wave propagation phenomenon in the membranous canal, leading to two flow phenomena within the endolymph which are in close interaction. First, the periodic deformation of the membranous labyrinth causes oscillating endolymph flow which forces the cupula to oscillate in phase with the sound stimulus. Second, these primary oscillations of the endolymph induce a steady flow component by a phenomenon known as steady streaming. We find that this steady flow of the endolymph is typically in ampullofugal direction. This flow leads to a quasi-steady deflection of the cupula which increases until the driving forces of the steady streaming are balanced by the elastic reaction forces of the cupula, such that the cupula attains a constant deflection amplitude which lasts as long as the sound stimulus. Both response types have been observed in the literature. In a sensitivity study, we obtain an analytical fit which very well matches our simulation results in a relevant parameter range. Finally, we correlate the corresponding eye response (vestibulo-ocular reflex) with the fluid dynamics by a simplified model of lumped system constants. The results reveal a "sweet spot" for TP within the audible sound spectrum. We find that the underlying mechanisms which lead to TP originate primarily from Reynolds stresses in the fluid, which are weaker at lower sound frequencies.

  6. Comparison of the capacity of two lipid A precursor molecules to express the local Shwartzman phenomenon.

    PubMed Central

    Galanos, C; Hansen-Hagge, T; Lehmann, V; Lüderitz, O

    1985-01-01

    It has been shown recently that a Salmonella lipid A precursor molecule (Ia) and its synthetic counterpart are inactive in expressing the local Shwartzman reaction in both homologous and heterologous systems in combination with lipid A. Precursor Ia contains a bisphosphoryl-beta-1,6-glucosamine disaccharide substituted by 4 mol of (D)-3-hydroxytetradecanoyl residues. Escherichia coli lipid A, on the other hand, which contains two additional non-hydroxylated acyl residues in the form of two 3-acyloxyacyl units, is highly active. We have recently isolated a lipid A precursor molecule (Ib) with the same basic structure as precursor Ia, which contains, however, one additional non-hydroxylated (hexadecanoic) fatty acid forming one 3-acyloxyacyl residue. A comparison of precursor Ia and Ib in homologous and cross-reacting Shwartzman systems confirmed that precursor Ia completely lacked the capacity to prepare the skin for, or to elicit, the Shwartzman reaction. In contrast, precursor Ib was strongly active in inducing the local Shwartzman reaction both when administered intradermally as a preparatory agent and when administered intravenously as a provocatory agent. The results indicate that the additional presence of at least one fatty acid either as such or as an acyloxyacyl residue (as in precursor Ib) is a prerequisite for the ability of the molecule to induce the local Shwartzman phenomenon. PMID:3886545

  7. 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

  8. 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.

  9. 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.

  10. 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

  11. 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

  12. 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

  13. Type II lepra reaction: an unusual presentation.

    PubMed

    Chauhan, S; D'Cruz, S; Mohan, H; Singh, R; Ram, J; Sachdev, A

    2006-01-27

    Ulcers with maculo-papular rash are an unusual presenting feature of leprosy. They occur as result of neuropathy, type-2 lepra reaction or Lucio's phenomenon. The hall mark of type-2 reaction is erythema nodosum. Very rarely it manifests as ulcerative skin lesions. We describe one such unusual case of a young male who presented with multiple ulcers and maculo-papular rash over the legs, chest and abdomen. In addition to this, he had fever, heart murmur, pulmonary infiltrates, neuropathy, and deranged liver function. A clinical differential diagnosis of infective endocarditis and systemic nectrozing vasculitis was made. Skin biopsy showed dense inflammation with lepra bacilli consistent with type-2 lepra reaction.

  14. Mesoglycan treatment in Raynaud phenomenon: a case series.

    PubMed

    Di Biase, A

    2013-06-01

    Raynaud's phenomenon (RP) is a common clinical disorder without cure or gold standard therapy. Mesoglycan is an well-balanced extract of glycosaminoglycans active on endothelial layers at microcirculatory level. Herein we investigated for the first time the efficacy and tolerability of mesoglycan on vasospastic attacks and videocapillaroscopy patterns in 25 consecutive patients with primary or secondary RP. During 12 months of add-on therapy, mesoglycan obtained a remarkable and significant reduction in the frequency of Raynaud attacks and an improvement of the capillaroscopy abnormalities in most patients, without important adverse effects, revealing a good convenience in the management if this condition.

  15. Laser Flash Effects: A Non-Visual Phenomenon.

    DTIC Science & Technology

    1982-06-18

    A)All49 LETERMAN ARMY INST OF RESEARCH PRESIDIO OF SAN FRANC--ETC F/ 611 LASEk FLASH EFFECTS: A NON-VISUAL PHENOMENON U) 0l’LA’SJ~rD Uf 82 D I...optical sighting devices in the combat environment would receive a laser flash directly in the fovea. Research on flash effects with human subjects has...the paralysis was reversed with neostigmine and atropine. Apparatus: Figure 1A is a diagram of the system used in this study. A Holobeam Series 300 Q

  16. The lean hunting phenomenon in gasoline engines - Part 2

    SciTech Connect

    Tanaka, M.; Yae, K.; Mochizuki, S.; Nishiwaki, N.

    1988-01-01

    The hunting phenomenon which occurs at the lean air-fuel ratio and under light conditions was studied and it was disclosed that this was not mechanical hunting and the fuel flow delay into the cylinder had a dominant effect on this lean hunting. This paper first describes the experiments which demonstrate that such a fuel flow delay can occur by changing the throttle position sinusoidally in various periods, and that Pmax (the maximum pressure in the cylinder) responds quite differently according to the magnitude of the air-fuel ratio; and then describes the effects of ignition energy and ignition timing on lean hunting.

  17. 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.

  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. 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.

  20. 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.

  1. Raynaud's phenomenon progressing to gangrene after vincristine and bleomycin therapy.

    PubMed

    Elomaa, I; Pajunen, M; Virkkunen, P

    1984-01-01

    Vascular symptoms after vinca-alcaloids and bleomycin are known. We report a 50-year-old woman who was cigarette smoker and who had had the syndrome of Raynaud's phenomenon for two years before she developed non-Hodgkin lymphoma. She was treated with chemotherapy including vincristine and bleomycin. Immediately after the second course of chemotherapy she had severe vertigo, nystagmus, dysarthria and dysphagia. The fingers remained cyanotic and became extremely painful despite stellatum blockade, intra-arterial vasodilators and thoracic sympathectomy. Two digits of the left hand were partially amputated because of gangrenous areas on the fingertips. The cerebral symptoms disappeared.

  2. Advances in the treatment of Raynaud’s phenomenon

    PubMed Central

    Levien, Terri L

    2010-01-01

    Raynaud’s phenomenon is a common condition characterized by vasospasm of the digital arteries and resulting cyanosis and redness. It often does not require pharmacologic management, but in some cases symptoms are severe and pharmacologic management is necessary. Calcium channel blockers are often used first-line, but in some patients are ineffective. Patients with severe symptoms or intolerance to available therapies have prompted exploration of alternative therapies, including endothelin antagonists, phosphodiesterase-5 inhibitors, antioxidants, newer vasodilators, statins, and botulinum toxin. These newer therapies provide the focus for this review. PMID:20448801

  3. Effect of advection on transient ion concentration-polarization phenomenon

    NASA Astrophysics Data System (ADS)

    Rosentsvit, Leon; Park, Sinwook; Yossifon, Gilad

    2017-08-01

    Here, we studied the effect of advection on the transient ion concentration-polarization phenomenon in microchannel-membrane systems. Specifically, the temporal evolution of the depletion layer in a system that supports net flow rates with varying Péclet values was examined. Experiments complemented with simplified analytical one-dimensional semi-infinite modeling and numerical simulations demonstrated either suppression or enhancement of the depletion layer propagation against or with the direction of the net flow, respectively. Of particular interest was the third-species fluorescent dye ion concentration-polarization dynamics which was further explained using two-dimensional numerical simulations that accounted for the device complex geometry.

  4. 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

  5. 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).

  6. 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.

  7. [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.

  8. [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". Copyright © 2013 Instituto Nacional de Cardiología Ignacio Chávez. Published by Masson Doyma México S.A. All rights reserved.

  9. 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.

  10. 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.

  11. Wave-Wave Coupling: A Nonlinear Phenomenon of Classical Physics

    NASA Astrophysics Data System (ADS)

    Infeld, E.

    2002-12-01

    Linear physics does not admit the possibility of wave coupling. With the advent of nonlinear research, wave-wave coupling has been observed and described theoretically in many media. For example, in hydrodynamics the Euler equations can lead to the Nonlinear Schroedinger Equation (NLS), which in turn admits three-wave coupling. Simple theory yields surprisingly good results [1, 2]. In plasma physics, the wave coupling phenomenon can be derived directly from the Vlasov equation [3]. Recent interest has been renewed when four-wave coupling was observed in experiments on Bose-Einstein condensates. Here, a successful theory has recently been developed based on the Gross-Pitayevski equation, a NLS for this condensate. Although now four waves may couple instead of three, the ideas and even the formalisms are almost identical [4]. Other fields in which the phenomenon is observed include optics and even population studies. When looking for this effect in new fields, one should ask whether similar coupling mechanisms are in place. References [1] E Infeld, Phys Rev Letters 47 717, 1981 [2] E Infeld and G Rowlands, Nonlinear Waves, Solitons and Chaos, CUP, 1990, second edition, Chapter 5. [3] R C Davidson, Methods in Nonlinear Plasma Theory, Academic, NY, 1972, chapter 6. [4] M. Trippenbach et al., Phys. Rev. A 62, 023608, 2000.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. A bursting phenomenon in a vortex-gas boundary layer

    NASA Astrophysics Data System (ADS)

    Sekaran, Aarthi; Narasimha, Roddam; Govindarajan, Rama

    2014-11-01

    Bursts are a central phenomenon in turbulent boundary layers as they are an integral part of turbulent energy and stress production. They have consequently been a continuing area of interest since the 1970s following the detailed investigations of Kline et al. (1967). Despite several attempts to understand their dynamics, it has been difficult to arrive at a consensus even on the scaling of the burst frequency. The present investigation simulates the outer part of a plane turbulent boundary layer using the vortex-gas model, in a first step towards understanding the role of the outer layer in boundary layer dynamics. Preliminary results indicate the formation of regions of concentrated vorticity near the wall, at a frequency that is independent of the initial vortex configuration but a function of the mean velocity profile. Further, comparisons with existing experimental data indicate a burst frequency which when scaled on outer variables, is within the range of scatter among different studies. Quadrant occupancy statistics are also related to those in conventional boundary layers. It appears as if a bursting phenomenon of some kind may be a general feature of an inviscid, wall-bounded shear flow, and does not necessitate inclusion of either viscosity or three-dimensionality.

  17. The clinicide phenomenon: an exploration of medical murder.

    PubMed

    Kaplan, Robert

    2007-08-01

    The aim of this paper is to explore the phenomenon of clinicide. The study of medical killers is barely in its infancy. Clinicide is the unnatural death of multiple patients in the course of treatment by a doctor. Serial medical killing is a relatively new phenomenon. The role model is Dr Marcel Petiot, the worst serial killer in French history. More recently, Dr Harold Shipman was Britain's worst serial killer and in the United States and Zimbabwe, Dr Michael Swango killed 60 patients. A number of doctors have such high patient death rates that it cannot be ignored. At some level, these doctors have an awareness of what they are doing, countered by an overweening refusal to acknowledge the implications or desist from further treatment. Treatment killer offences usually occur on the basis of serial mental illness, but may include the contentious area of euthanasia killing. Doctors have frequently been accomplices in state repression, brutality and genocide in direct contravention to their sanctioned role to relieve suffering and save life. They have become mass murderers on an exponential scale, making any comparison with a doctor killing his own patients almost risible. Many clinicidal doctors have extreme narcissistic personalities, a grandiose view of their own capability and inability to accept that they could be criticized or need assistance from other doctors. Such doctors develop a God-complex, getting a vicarious thrill out of ending suffering and by determining when a person dies.

  18. The no-reflow phenomenon: epidemiology, pathophysiology, and therapeutic approach.

    PubMed

    Alfayoumi, Fadi; Srinivasan, Venkatraman; Geller, Mark; Gradman, Alan

    2005-01-01

    Over the past 20 years, advances in the management of ST segment elevation myocardial infarction have focused on the rapid achievement of patency in the infarct-related artery. The limitation of this therapeutic strategy has been exposed with the development of diagnostic techniques to assess coronary microcirculation, including myocardial contrast echo, magnetic resonance imaging, myocardial perfusion grading, and the coronary flow wire. These methods have expanded our ability to understand and recognize the no-reflow phenomenon, which describes the absence of tissue perfusion despite epicardial coronary artery patency and flow. Although the mechanisms responsible for the development of no reflow are not fully understood, the end result is microvascular damage produced by microvascular obstruction or reperfusion injury. Ideally, early recognition of the no-reflow phenomenon should provide an opportunity for therapeutic intervention designed to augment tissue perfusion and maintain the viability of myocardium at risk. A number of pharmacologic agents are being used in conjunction with percutaneous transluminal coronary angioplasty in an attempt to improve microvascular perfusion. These include IIb/IIIa receptor antagonists, adenosine, verapamil, and the experimental agent nicorandil. In the new millennium, the emphasis of reperfusion therapy is being shifted downstream from its exclusive focus on the epicardial artery to assuring normal blood flow at the tissue level. This article will review the epidemiology, pathophysiology, and therapeutic approach to this vexing clinical problem.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Livedo reticularis in type 2 lepra reaction: A rare presentation.

    PubMed

    Naveen, Kikkeri Narayanasetty; Athanikar, Sharatchandra Bhimrao; Hegde, Spandana Prakash; Athanikar, Vidisha Sharatchandra

    2014-04-01

    Type 2 lepra reaction or erythema nodosum leprosum (ENL) is an immune complex syndrome that occurs mostly in lepromatous leprosy and sometimes in borderline lepromatous leprosy patients. We present an untreated case of lepromatous leprosy, who presented with type 2 lepra reaction and livedo reticularis. Livedo reticularis, though seen in lucio phenomenon, is not a part of type 2 lepra reaction. The case is being reported for its rarity.

  5. 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.

  6. 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.

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Evolution as a self-organized critical phenomenon.

    PubMed Central

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

    1995-01-01

    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 "self-organized critical" state where periods of stasis alternate with avalanches of causally connected evolutionary changes. This characteristic behavior of natural history, known as "punctuated equilibrium," 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. Images Fig. 3 Fig. 6 Fig. 7 PMID:7761475

  15. An experimental study of the dynamic Leidenfrost phenomenon

    NASA Astrophysics Data System (ADS)

    Khavari, Mohammad; Saifullah, Mohammad S. M.; Tran, Tuan

    2016-11-01

    Complete separation between an impacting droplet and a superheated surface can be achieved if the surface temperature is sufficiently high causing spontaneous generation of a vapor layer under the droplet. The transition to such vapor-induced separation, or Leidenfrost regime, depends on numerous parameters such as materials properties and the impact conditions including the impact velocity and surface temperature. Here we provide detailed experimental observations of several distinct impact dynamics at the Leidenfrost transition in order to understand the physical mechanism of such transition. We focus on the liquid-solid interface to identify necessary conditions for Leidenfrost transition to occur. We show that detailed and quantitative measurements of the wetted area during impact may lead to a physical understanding of the Leidenfrost phenomenon.

  16. Thymineless Death Lives On: New Insights into a Classic Phenomenon.

    PubMed

    Khodursky, Arkady; Guzmán, Elena C; Hanawalt, Philip C

    2015-01-01

    The primary mechanisms by which bacteria lose viability when deprived of thymine have been elusive for over half a century. Early research focused on stalled replication forks and the deleterious effects of uracil incorporation into DNA from thymidine-deficient nucleotide pools. The initiation of the replication cycle and origin-proximal DNA degradation during thymine starvation have now been quantified via whole-genome microarrays and other approaches. These advances have fostered innovative models and informative experiments in bacteria since this topic was last reviewed. Given that thymineless death is similar in mammalian cells and that certain antibacterial and chemotherapeutic drugs elicit thymine deficiency, a mechanistic understanding of this phenomenon might have valuable biomedical applications.

  17. 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.

  18. Modeling of Electromagnetic Phenomenon in Fractional Dimensional Space

    NASA Astrophysics Data System (ADS)

    Zubair, Muhammad; Ang, L. K.

    Fractional dimensional space has emerged as an extremely useful concept in many areas of physics, including electromagnetic (EM) theory. The development made in the area of fractional calculus has made it possible to study the most important physical phenomenon in a generalized D-dimensional fractional space. It is worthwhile to mention that many natural objects, such as clouds, snowflakes, rough surfaces, cracks, turbulence in fluids, are aptly described by dimensions of fractional order. Therefore, EM wave propagation in such fractal media is best characterized by considering an effective space of non-integer (fractional) dimensions. Here we present the recent developments in the study of differential Maxwell equations in a D-dimensional fractional space, where D is a non-integer value. Same examples will be used in order to show the transition to the traditional non-fractional conditions or settings.

  19. 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.

  20. 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.

  1. [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.

  2. [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.

  3. [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.

  4. [Diffuse lepromatous leprosy disclosed by cutaneous vasculitis. The Lucio phenomenon].

    PubMed

    Bernadat, J P; Faucher, J F; Huerre, M

    1996-01-01

    Lucio's phenomenon, also called necrotizing erythema, is a rare acute manifestation which sometimes introduces diffuse lepromatous leprosy, almost exclusively in Central American populations. A 76-year-old polynesian man of chinese ethnic origin had necrotizing erythema for several months before development of Lucio's leprosy. The patient had necrotizing lesions of the lower limbs with large polygonal scars and poor general health status. Diagnosis was based on the discovery of acid-fast bacilli at the pathology examination of skin biopsies. The necrotizing zones appeared as cutaneous vasculitis with angiogenesis of the superficial dermis and presence of Hansen bacilli within the endothelium. This case of diffuse lepromatous leprosy, the first reported in the South Pacific, emphasizes the polymorphism of leprosy and the importance of recognizing rare clinical forms, especially in the tropics. Anti-Hansen drugs are effective.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. Coronary Slow Flow Phenomenon and Atrioventricular Block: A Case Report.

    PubMed

    Masoumi, Mohammad; Mohammadi, Khadije

    2017-04-01

    The coronary slow flow phenomenon (CSFP) is characterized by a delayed coronary blood flow in the absence of an obstructive coronary artery disease. Although the relation between the CSFP and myocardial ischemia has been reported previously, there is no knowledge about the relationship between the CSFP and the conduction system disorder. In this case report, we describe a patient with the CSFP presenting with complete heart block (CHB). The patient was a middle-aged woman with a history of diabetes, hypertension, and prior Coronary Care Unit admission presenting with dizziness, lightheadedness, and presyncope. Electrocardiography revealed CHB with no significant ST-T change. Cardiac enzymes and other routine lab tests were normal. The patient underwent temporary pacemaker implantation. Due to persistent atrioventricular block and suspicion of ischemic heart disease, she underwent coronary angiography, which showed the CSFP and no significant stenosis. The patient was discharged after permanent pacemaker implantation and remained asymptomatic at 3 months' follow-up.

  13. Venusian "hot spots": physical phenomenon and its quantification.

    PubMed

    Goncharov, V P; Gryanik, V M; Pavlov, V I

    2002-12-01

    An overall picture of the Venusian hot spots phenomenon is considered in the framework of the simplest conceptual models that admit the solutions in the form of steadily rotating "hot" vortices. Model assumptions take into account only those features of the middle atmosphere in the polar region of Venus that are supported by observational data and are essential for understanding the physical mechanism initiating similar vortices. The problem is analyzed in the framework of both the pointlike and petal-like models of cyclostrophic vortices. Interpretation of these models as an upper and lower bound of a complete theory allows one to find the region of existence of the regimes responsible for the Venusian hot spots and also to establish and assess numerically conditions under which such vortices can be formed. The emphasis is on a comparison of the theoretically established results with the observational data.

  14. [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.

  15. The phenomenon of wetting at solid/solid interface

    NASA Astrophysics Data System (ADS)

    Haber, J.; Machej, T.; Czeppe, T.

    1985-03-01

    When a V 2O 5 crystallite is placed on an anatase pellet and heated at 823-923 K, vanadium ions migrate over the surface of anatase grains enveloping them in a thin overlayer. XPS, X-ray and EPR studies show that at 823 K a very thin layer is formed, its properties being strongly modified by interaction with the anatase support. At 923 K, on top of this inner layer an outer layer migrates, whose properties are similar to V 2O 5. As in the same conditions no migration is observed on rutile, it is concluded that this phenomenon is a manifestation of wetting of one oxide by another oxide, the difference in the surface free energy being the driving force of the migration.

  16. Management of Raynaud's phenomenon and digital ulcers in systemic sclerosis.

    PubMed

    Botzoris, Vasileios; Drosos, Alexandros A

    2011-07-01

    Raynaud's phenomenon (RP) and digital ulcers (DU) are the clinical manifestations of vasculopathy in systemic sclerosis. Both interfere with hand function and hold the possibility of severe complications, thus adversely influencing patients' quality of life. Managing RP and DU is often a challenge for the treating physician, who has to establish a treatment plan based upon knowledge of the current therapeutic options. The first step is to differentiate primary from secondary RP, where combining history and physical examination with diagnostic modalities, such as nailfold capillaroscopy, aids in reaching the correct diagnosis. Next a wide range of treatment options is offered nowadays, starting from first-line agents, as calcium channel blockers, to the more targeted-ones, like endothelin receptor antagonists. Research and clinical experience with each agent are reviewed in the text, as well as the combinations that more recently gain field in the treatment of DU.

  17. Racial Discrimination, Racial Identity, and Impostor Phenomenon: A Profile Approach.

    PubMed

    Bernard, Donte L; Hoggard, Lori S; Neblett, Enrique W

    2017-04-17

    This study examined the association between racial discrimination and the impostor phenomenon (IP) and the moderating influence of racial identity on this relationship. One hundred fifty-seven African American college students (68% female; mean age = 18.63) completed measures of racial discrimination, racial identity, and IP during 2 waves of data collection. Utilizing latent profile analyses, 4 patterns of racial identity were identified: Undifferentiated, Multiculturalist, Race-Focused, and Humanist. Racial discrimination predicted higher subsequent levels of IP. Racial identity did not moderate the impact of racial discrimination; however, students in the Multiculturalist and Humanist groups reported the lowest and highest levels of IP at Wave 2, respectively. IP is influenced by racial discrimination experiences as well as by the significance and meaning that individuals ascribe to being African American. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  18. Resonance phenomenon of the ATP motor as an ultrasensitive biosensor.

    PubMed

    Wang, Peirong; Zhang, Xiaoguang; Zhang, Xu; Wang, Xia; Li, Xueren; Yue, Jiachang

    2012-09-28

    We designed a rotary biosensor as a damping effector, with the rotation of the F(0)F(1)-ATPase driven by Adenosine Triphosphate (ATP) synthesis being indicated by the fluorescence intensity and a damping effect force being induced by the binding of an RNA molecule to its probe on the rotary biosensor. We found that the damping effect could contribute to the resonance phenomenon and energy transfer process of our rotary biosensor in the liquid phase. This result indicates that the ability of the rotary motor to operate in the vibration harmonic mode depends on the environmental conditions and mechanism in that a few molecules of the rotary biosensor could induce all of the sensor molecules to fluoresce together. These findings contribute to the theory study of the ATPase motor and future development of biosensors for ultrasensitive detection. Copyright © 2012 Elsevier Inc. All rights reserved.

  19. 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.

  20. Condensation in a Capped Capillary is a Continuous Critical Phenomenon

    NASA Astrophysics Data System (ADS)

    Parry, A. O.; Rascón, C.; Wilding, N. B.; Evans, R.

    2007-06-01

    We show that condensation in a capped capillary slit is a continuous interfacial critical phenomenon, related intimately to several other surface phase transitions. In three dimensions, the adsorption and desorption branches correspond to the unbinding of the meniscus from the cap and opening, respectively, and are equivalent to 2D-like complete-wetting transitions. For dispersion forces, the singularities on the two branches are distinct, owing to the different interplay of geometry and intermolecular forces. In two dimensions we establish precise connection, or covariance, with 2D critical-wetting and wedge-filling transitions: i.e., we establish that certain interfacial properties in very different geometries are identical. Our predictions of universal scaling and covariance in finite capillaries are supported by extensive Ising model simulation studies in two and three dimensions.

  1. 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.

  2. 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

  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. 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.

  5. Challenges in Understanding and Modeling the SAPS Phenomenon

    NASA Astrophysics Data System (ADS)

    Anderson, P. C.; Landry, R. G.

    2016-12-01

    SAPS are a profound example of Ionosphere/Thermosphere/Magnetosphere coupling. They lie on subauroral field lines that map to the inner magnetosphere and modify magnetospheric convection. Indeed, the potential drop across them has been shown to sometimes exceed 70 kV, constituting more than half of the total cross-polar-cap-potential drop at times. They modify the plasmasphere, creating the plasmaspheric plume, and thus impact the energization and loss processes in the radiation belts. They reduce the ionospheric conductivity providing a feedback mechanism that further modifies the subauroral fields and thus the convection in the inner magnetosphere. They also impact the thermosphere producing significant thermospheric winds that impact the thermospheric structure. Thus it is critical that we develop a complete understanding of the phenomenon and the ability to accurately model it. Even after decades of study, there are many things that we still don't fully understand about SAPS. For instance, what is the importance of ionospheric preconditioning and the mid-latitude trough on SAPS formation and development? How does the ionosphere/thermosphere system respond and how does that response impact SAPS evolution? What is the role of field-aligned currents and how does their evolution impact SAPS evolution? How does the distribution of precipitating auroral particles at the equatorward edge of the auroral oval impact SAPS development? How are SAPS observed during storms different from SAPS observed during isolated substorms and what is the importance of storm/substorm phase on SAPS structure? I will give a review of what we know about SAPS and discuss these outstanding questions and the implications on our attempts to model the SAPS phenomenon.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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

  12. Baseball hitting, binocular vision, and the Pulfrich phenomenon.

    PubMed

    Hofeldt, A J; Hoefle, F B; Bonafede, B

    1996-12-01

    To determine if dimming the light to 1 eye affects baseball hitting (motion-in-depth) and if binocular interaction influences the ability to hit a baseball. The ability to hit baseballs in a batting cage was measured under conditions of (1) no filter before either eye, (2) neutral density filters before both eyes, and (3) a neutral density filter before 1 eye, while viewing with both eyes. Batting scores were based on the number of hits, fouls, and misses. A neutral density filter of 0.6 optical density before both eyes had no significant effect on batting ability compared with no filter (87% vs 94%). While viewing binocularly, a filter before 1 eye caused a significantly greater reduction in hitting scores than when the filter was placed before the opposite eye (36% vs 80%). This greater effect of 1 eye on hitting scores denotes an ocular preference or dominance within the motion stereopsis system. The eye associated with the greater reduction in hitting ability when dimmed by a filter was termed the dominant eye for motion stereopsis. In comparison with placing 0.6-optical density filters before both eyes, the same filter before the dominant eye reduced hitting ability (36% vs 87%), but when the filter was placed before the nondominant eye, the hitting ability was not significantly reduced (80% vs 87%). The batting scores decreased as filter densities increased from 0.3- to 0.6-optical density, and the effect was significantly more for the dominant eye than for the nondominant eye. Binocular vision contributes to the precise localization of a pitched baseball, and one eye influences baseball hitting more than the other eye. The motion-in-depth channel (baseball hitting) shares a sensitivity to unequal binocular illumination with the sideways-motion channel (Pulfrich phenomenon). The timing of the impulses conducted from the eyes appears to be critical for the precise localization of objects processed by either the motion-in-depth (baseball hitting) or the

  13. V838 Monocerotis revisited: Space phenomenon imitates art

    NASA Astrophysics Data System (ADS)

    2004-03-01

    V838 Monocerotis revisited: Space phenomenon imitates art hi-res Size hi-res: 558 Kb Credits: NASA, the Hubble Heritage Team (AURA/STScI) and ESA V838 Monocerotis revisited: Space phenomenon imitates art "Starry Night", Vincent van Gogh's famous painting, is renowned for its bold whorls of light sweeping across a raging night sky. Although this image of the heavens came only from the artist's restless imagination, a new picture from the NASA/ESA Hubble Space Telescope bears remarkable similarities to the van Gogh work, complete with never-before-seen spirals of dust swirling across trillions of kilometres of interstellar space. This image, obtained with the Advanced Camera for Surveys on February 8, 2004, is Hubble's latest view of an expanding halo of light around a distant star, named V838 Monocerotis (V838 Mon). The illumination of interstellar dust comes from the red supergiant star at the middle of the image, which gave off a flashbulb-like pulse of light two years ago. V838 Mon is located about 20,000 light-years away from Earth in the direction of the constellation Monoceros, placing the star at the outer edge of our Milky Way galaxy V838 Monocerotis revisited: Space phenomenon imitates art hi-res Size hi-res: 1989 kb Credits: NASA, the Hubble Heritage Team (AURA/STScI) and ESA V838 Monocerotis revisited: Space phenomenon imitates art "Starry Night", Vincent van Gogh's famous painting, is renowned for its bold whorls of light sweeping across a raging night sky. Although this image of the heavens came only from the artist's restless imagination, a new picture from the NASA/ESA Hubble Space Telescope bears remarkable similarities to the van Gogh work, complete with never-before-seen spirals of dust swirling across trillions of kilometres of interstellar space. This image, obtained with the Advanced Camera for Surveys on February 8, 2004, is Hubble's latest view of an expanding halo of light around a distant star, named V838 Monocerotis (V838 Mon). The

  14. 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.

  15. [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)

  16. 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).

  17. THE NATURE OF THE TOXIN-ANTITOXIN FLOCCULATION PHENOMENON

    PubMed Central

    Bronfenbrenner, J. J.; Reichert, Philip

    1926-01-01

    1. Animals immunized with the formalinized filtrates of young toxic cultures of B. botulinus produce an antitoxic serum poor in precipitins. 2. Animals immunized with the formalinized filtrates of old and partly autolyzed toxic cultures produce an antitoxic serum containing precipitins. 3. Animals immunized with toxin-free autolyzed bacteria produce a serum free from antitoxin but rich in specific precipitins. 4. Animals immunized with the filtrates of an atoxic variant produce a serum free from antitoxin but rich in precipitins for the homologous toxin. 5. Animals immunized with the washed bacteria of the atoxic variant produce a serum that contains no antitoxin, but is rich in precipitins for the homologous toxin. 6. Removal of the precipitins by flocculation with a non-toxic antigen does not materially reduce the antitoxic value of a serum. 7. Removal of the proteins of the antigen by add coagulation removes the specific precipitable substance. 8. All the sera that contain precipitins produce the specific flocculus when combined with homologous toxins, anatoxins, or with the filtrates of the atoxic variant. The flocculation is restricted within the type. The amount of the precipitate and the width of the zone vary approximately with the estimated amount of bacterial protein in the antigen that is used for the immunization of animals. We conclude, therefore, that the toxin-antitoxin flocculation is a specific bacterial precipitation phenomenon. PMID:19869206

  18. 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.

  19. 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.

  20. The phenomenon of adolescents placing pressure on their parents.

    PubMed

    Bester, Garfield; Marais, Amanda C

    2014-01-01

    Parents are under pressure from their adolescent children if they, contrary to their own convictions, are compelled to bend rules or adapt decisions to submit to the demands of their children. The objective of this investigation was to determine which factors contribute to this phenomenon. The sample comprised 177 adolescents and their parents in the Mpumalanga province. Variables taken into account were individual factors (gender, age and personality of parents and adolescents); factors related to the family (family structure, working circumstances of parents, family relationships and birth order position of adolescents); developmental factors (identity formation of adolescents); and wider contextual factors (peer pressure during adolescence). From the parents' side factors such as self-concept, personality and parent-adolescent relationship explained almost 62% of the variance in the pressure that parents experience. Only one prominent adolescent factor could be identified, namely adolescent-parent relationship (seen from the adolescents' side). The results indicate that the pressure which parents encounter from their adolescent children is associated with parental variables rather than adolescent variables. Adolescents do not deliberately plan to place their parents under pressure, but factors on the parents' side create such a situation.

  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. ALS pathophysiology: insights from the split-hand phenomenon.

    PubMed

    Menon, Parvathi; Kiernan, Matthew C; Vucic, Steve

    2014-01-01

    The aim of the present study was to assess whether peripheral mechanisms, mediated through axonal dysfunction, may contribute to development of the split-hand in amyotrophic lateral sclerosis (ALS). Median and ulnar nerve motor axonal excitability studies were undertaken on 21 ALS patients with motor responses recorded over the abductor pollicis brevis (APB), abductor digit minimi (ADM) and first dorsal interosseous (FDI) muscles, and results compared to 24 controls. The split-hand index (SI), an objective biomarker of preferential atrophy of APB and FDI muscles, was significantly reduced in ALS (SI(ALS) 7.8 ± 1.7, SICONTROLS 13.1 ± 1.1, P<0.0001). Axonal excitability studies identified significant prolongation of strength-duration time constant in ALS patients when recording over the APB (P<0.05) and ADM axons (P<0.05) but not FDI axons (P=0.22). Greater changes in depolarising threshold electrotonus were also evident across the range of intrinsic hand muscles and were accompanied by increases of superexcitability in APB (P<0.01) and FDI (P<0.05) axons. The present study reinforces the significance of the split-hand phenomenon in ALS and argues against a significant peripheral contribution in the underlying development. Axonal dysfunction may appear as a downstream process that develops secondary to the intrinsic pathophysiological origins of ALS. Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  4. 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.

  5. 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.

  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. 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.

  8. Environmental refugees: a growing phenomenon of the 21st century.

    PubMed Central

    Myers, Norman

    2002-01-01

    There is a new phenomenon in the global arena: environmental refugees. These are people who can no longer gain a secure livelihood in their homelands because of drought, soil erosion, desertification, deforestation and other environmental problems, together with the associated problems of population pressures and profound poverty. In their desperation, these people feel they have no alternative but to seek sanctuary elsewhere, however hazardous the attempt. Not all of them have fled their countries, many being internally displaced. But all have abandoned their homelands on a semi-permanent if not permanent basis, with little hope of a foreseeable return. In 1995, environmental refugees totalled at least 25 million people, compared with 27 million traditional refugees (people fleeing political oppression, religious persecution and ethnic troubles). The total number of environmental refugees could well double by the year 2010, and increase steadily for a good while thereafter as growing numbers of impoverished people press ever harder on overloaded environments. When global warming takes hold, there could be as many as 200 million people overtaken by sea-level rise and coastal flooding, by disruptions of monsoon systems and other rainfall regimes, and by droughts of unprecedented severity and duration. PMID:12028796

  9. 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.

  10. 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.

  11. 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.

  12. [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.

  13. 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.

  14. 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. Copyright © 2016 Diabetes India. Published by Elsevier Ltd. All rights reserved.

  15. 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.

  16. Influence of reactor surface materials on the ozone zero phenomenon

    NASA Astrophysics Data System (ADS)

    Seyrling, Sieghard; Müller, Marco; Ramoino, Luca

    2017-06-01

    It is long known that for highly efficient ozone production in a dielectric barrier discharge (DBD), it is beneficial to add a small quantity of nitrogen to the oxygen feed gas. When operated in very pure oxygen without any significant nitrogen content, the ozone formation even drops to zero under certain operating conditions. This is known in the field as the "ozone zero phenomenon", or OZP. The exact mechanisms of said effect, however, are still not understood and a subject of ongoing research. In the present work, we investigated the influence of different reactor surface materials, and their changes when exposed to plasma, on their influence on ozone formation under different nitrogen conditions. The metal powder deposited on the reactor surfaces by sputtering effects was found to have a buffering effect on the time scale needed for the OZP to fully develop. We conclude that the surface of the DBD reactor, in particular the available surface area for nitrogen compounds to adsorb to, is the crucial element in understanding the processes behind the OZP.

  17. 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.

  18. Kin recognition is a nutrient-dependent inducible phenomenon.

    PubMed

    Palmer, Andrew G; Ali, Maysaa; Yang, Shukun; Parchami, Neda; Bento, Thiara; Mazzella, Amanda; Oni, Musa; Riley, Michael C; Schneider, Karl; Massa, Nicole

    2016-09-01

    Recognition and response to prospective competitors are crucial variables that must be considered in resource distribution and utilization in plant communities. Associated behaviors are largely mediated through the exchange of low-molecular weight exudates. These cues can significantly alter the root system architecture (RSA) between neighboring plants and are routinely sensitive enough to distinguish between plants of the same or different accessions, a phenomenon known as kin recognition (KR). Such refined discrimination of identity, based on the composition and detection of patterns of exudate signals is remarkable and provides insight into the chemical ecology of plant-plant interactions. The discovery that KR occurs in Arabidopsis thaliana provides a model system to resolve many of the mechanistic questions associated with this process. We hypothesized that the low-molecular weight cues which direct changes to the RSA during KR was driven by nutrient availability. Here we present evidence in support of a nutrient-inducible model for KR. Our findings underscore how exudate production and detection are influenced by nutrient availability as well as how this information is integrated into 'decisions' about competition and root system architecture which may have broader impacts on community composition.

  19. Kin recognition is a nutrient-dependent inducible phenomenon

    PubMed Central

    Palmer, Andrew G.; Ali, Maysaa; Yang, Shukun; Parchami, Neda; Bento, Thiara; Mazzella, Amanda; Oni, Musa; Riley, Michael C.; Schneider, Karl; Massa, Nicole

    2016-01-01

    ABSTRACT Recognition and response to prospective competitors are crucial variables that must be considered in resource distribution and utilization in plant communities. Associated behaviors are largely mediated through the exchange of low-molecular weight exudates. These cues can significantly alter the root system architecture (RSA) between neighboring plants and are routinely sensitive enough to distinguish between plants of the same or different accessions, a phenomenon known as kin recognition (KR). Such refined discrimination of identity, based on the composition and detection of patterns of exudate signals is remarkable and provides insight into the chemical ecology of plant-plant interactions. The discovery that KR occurs in Arabidopsis thaliana provides a model system to resolve many of the mechanistic questions associated with this process. We hypothesized that the low-molecular weight cues which direct changes to the RSA during KR was driven by nutrient availability. Here we present evidence in support of a nutrient-inducible model for KR. Our findings underscore how exudate production and detection are influenced by nutrient availability as well as how this information is integrated into ‘decisions’ about competition and root system architecture which may have broader impacts on community composition. PMID:27552112

  20. [Study on the phenomenon of splashes and sprays from virology].

    PubMed

    Li, Yuan; Mei, Guo-yong; Jiang, Hui-ying; Wang, Gui-rong; Wei, Qiang; Han, Lu; Wang, Lei; Tian, Chan; Han, Wei-fang; Wu, Gui-zhen; Wang, Ke-xia; Han, Jun

    2009-12-01

    To investigate the phenomenon of accidental splashes and sprays from manipulation of recombinant virus material and to measure the approximate spilled distance when recombinant virus material inadvertently dropped in the biosafety laboratory. first, two groups owning different experience simulated the course of accidental spills and splashes by recombinant adenovirus (rADV) which expressed green fluorescence protein (GFP), the GFP signal were observed in 96 well cell plate after spills appeared; Second, the routine two heights (75 cm and 110 cm) and capacity (1 ml, 1.5 ml, 4 ml and 8 ml) of virus were chose to simulate the experiment of unexpected dropping. First, the positive quantity of the first group owning 5 years' experience is much less than the second group owning 2 years' work experience, the former was 7 positive wells, the latter was 81 positive when they used the pipette to operation. Second, when the unclosed test tubes (1 ml, 1.5 ml, 4 ml and 8 ml recombinant virus) inadvertently dropped, the largest spill distance was 0.92 m, 1.57 m, 2.63 m and2.68 m respectively. The better experience is important to make sure safety when we make infectious material; the contaminated distance increased with the amount of recombinant virus material.

  1. 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.

  2. 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.

  3. [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.

  4. 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

  5. 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.

  6. 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

  7. 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

  8. 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

  9. 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.

  10. Palinacousis--evidence to suggest a post-ictal phenomenon.

    PubMed

    Mohamed, Wazim; Ahuja, Niharika; Shah, Aashit

    2012-06-15

    Palinacousis is a paroxysmal auditory illusion in which perseveration of an external auditory stimulus occurs after cessation of the stimulus. The subjects recognize the illusory nature of this experience, which is often a fragment of the last sentence they heard. Palinacousis has been reported in only a few documented cases. It has been described as an aura, a component of complex partial seizures, and a post-ictal event. We put forward evidence demonstrating palinacousis as a post-ictal event. A 68-year-old woman presented with an acute sensory aphasia, and an EEG showed frequent epileptiform discharges from the left temporo-parietal region. MRI showed an enhancing mass in the left inferior parietal lobule that was consistent with a metastasis. A CT scan of the thorax later showed an enhancing mass in the left lung that was determined to be an invasive non-small cell carcinoma. Treatment with levetiracetam resulted in loss of epileptiform activity on EEG and resolution of aphasia, but soon afterward, she started complaining of recurrent auditory illusions in her right ear. These consisted of phrases from the ends of sentences she heard. Continuous EEG monitoring during her auditory symptoms showed intermittent left temporal slowing but no epileptiform discharges or electrographic seizures. An FDG-PET scan with the glucose uptake phase during episodes of auditory illusions revealed hypometabolism of bilateral medial temporal cortices and increased uptake in the metastatic tumor. A systematic review identified 14 cases with palinacousis since 1981. Cases prior to that were excluded due to the lack of sufficient data. We propose that palinacousis is a "negative" phenomenon, at least in some individuals. It occurs with a loss of function of a region of the brain that normally suppresses auditory perseveration. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. 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).

  12. 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).

  13. Living through the end: The phenomenon of dying at home.

    PubMed

    Solomon, Diane N; Hansen, Lissi

    2015-04-01

    To explore the unique lived experiences of one patient who died at home and her family members, and to interpret how dying at home influenced patterns of bereavement for this patient's family. Benner's (1985) interpretive phenomenological approach was employed to get at the embedded nature of the social phenomenon of dying at home, uncovering what may be taken for granted by participants - in this case, during and after the patient's home hospice course. The participants were a 78-year-old female diagnosed with amyotrophic lateral sclerosis six months prior to death, her husband, and three of her four children. In line with the patient's wish to die at home, she voluntarily forewent food and drink when she no longer wished to watch her body deteriorate and felt that her life had run its course. She informed her family of this plan, and all were supportive. For data collection, separate single in-depth interviews were conducted with the deceased three months prior to death, and after death with three of her four children and her spouse of 60 years. For data analysis, the interview transcripts were coded for paradigm cases, exemplars, and themes. The paradigm case, "The Meaning of Being at Home," revealed that for study participants, remaining home with hospice provided a richly familiar, quiet, and safe environment for being together over time and focusing on relationships. Exemplars included "Driving Her Own Course" and "Not Being a Burden." Salient themes encompassed patient and family characteristics, support, emotions, the value of time, and aspects of the healthcare team. End-of-life care providers need to hold a patient-centered, family-focused view to facilitate patient and family wishes to remain home to die. Investigation into family relationships, from the perspectives of both patient and family members, longitudinally, may enrich understanding and ability and help patients to die at home.

  14. Symptomatic epidural gas cyst associated with discal vacuum phenomenon.

    PubMed

    Kakitsubata, Yousuke; Theodorou, Stavroula J; Theodorou, Daphne J; Yuko, Miyata; Ito, Yasunori; Yuki, Yasuhiro; Wada, Shoichi; Maehara, Toyo

    2009-10-01

    Four cases of computed tomography and magnetic resonance imaging documented lumbar nerve root compression associated with a vacuum disc communicating with the epidural space are presented. To give an insight into the mechanism of nerve root compression associated with vacuum disc phenomenon. Few cases of lumbar radiculopathy resulting from epidural gas have been reported and illustrated using cross-sectional imaging studies. The medical records, imaging examinations, and surgical findings (when available) of 4 symptomatic patients with epidural and intradiscal gas collections were reviewed. Three patients underwent surgery with needle aspiration of the epidural gas, and 1 patient was treated conservatively. Clinical symptoms of epidural gas cyst were similar to those of other more common causes of nerve root compression. Computed tomography and magnetic resonance imaging findings showed intraspinal gas collection associated with a vacuum disc. One patient had an additional vertebral pneumatocyst. Although evacuation of intraspinal gas resulted in complete cure or major neurologic improvement in 3 patients, an initial period of observation is warranted because gas may disappear spontaneously as in 1 of our patients. All 4 patients recovered full motor and sensory functions of the lower extremities. One year later, patients were completely free of symptoms. Although the vacuum disc is considered a common imaging finding of no or not much pathologic significance, occasionally intradiscal gas may leak into the spinal canal. Detection of an epidural gaseous collection at the same level with a vacuum disc strongly suggests a communication between the intervertebral disc and the epidural space. Epidural gas collections can be implicated as a possible cause of radicular symptoms and should be considered in the differential diagnosis of lumbar radiculopathy.

  15. The phenomenon of "fluid creep" in acute burn resuscitation.

    PubMed

    Saffle, Jeffrey I L

    2007-01-01

    Several reports have documented that modern burn patients receive far more resuscitation fluid than predicted by the Parkland formula-a phenomenon termed "fluid creep." This article reviews the incidence, consequences, and possible etiologies of fluid creep in modern practice and uses this information to propose some therapeutic strategies to reduce or eliminate excessive fluid resuscitation in burn care. A literature review was performed of historical references that form the foundation of modern fluid resuscitation, as well as reports of fluid creep and its consequences. The original Parkland formula required a 24-hour volume of 4 ml/kg/%TBSA lactated Ringer's solution followed by an infusion of 0.3-0.5 ml/kg/ %TBSA plasma. Modern iterations of this formula have omitted the colloid bolus. Numerous exceptions to the formula have been noted, most consistently patients with inhalation injuries. In contrast, recent reports document greatly increased fluid requirements in unselected patients, which seems to consist largely of progressive edema formation in unburned areas, increasing after the first 8 hours post-burn. This has been linked to occurrence of the abdominal compartment syndrome and other serious complications. Strategies to reduce fluid creep include the avoidance of early overresuscitation, use of colloid as a routine component of resuscitation or for "rescue," and adherence to protocols for fluid resuscitation. Fluid creep is a significant problem in modern burn care. Review of original investigations of burn shock, coupled with modern reports of fluid creep, suggests several mechanisms by which this problem can be controlled. Prospective trials of these therapies are needed to confirm their effectiveness.

  16. Microvascular reactivity during sympathetic stimulations in Raynaud's phenomenon.

    PubMed

    Stoyneva, Zlatka B; Dermendjiev, Svetlan M; Medjidieva, Daniela G; Vodenicharov, Vlayko E

    2016-12-01

    The objective of the study was to assess skin autonomic microvascular reactivity to sympathetic stimulations and its association with primary and secondary Raynaud's phenomenon (RP). Laser-Doppler recorded finger pulp skin blood flow was monitored during orthostatic and deep breathing tests of 4 subjects groups, each of them composed of 20 subjects: group 1, healthy controls; group 2, vibration-induced secondary RP (vRP); group 3, primary RP (pRP); group 4, systemic sclerosis-related secondary RP (sclRP). Within groups comparisons by Wilcoxon matched pairs rank test and between groups by Bonferroni's multiple test for unpaired data were done using SPSS Statistics software. Reliably lower initial perfusion values were established in all the RP patients. The local sympathetic axon-reflex mediated responses to orthostasis were reduced in all RP groups with increased perfusions in upright posture instead of decreased. The vasoconstrictor responses to deep breathing tended to increase instead of decreasing in the vRP and pRP groups, while in the sclRP group the perfusions decreased. Strong correlations between the initial finger pulp perfusions and the orthostatic and deep breathing perfusion responses were found in the control, pRP and vRP groups (P<0.0001) and a modest correlation between the initial perfusions and the deep breathing perfusion responses in the sclRP group. Abnormal cutaneous microvascular reactivity to central and local axon-reflex sympathetic stimulations was established in RP patients reflecting self-regulatory dysfunctions which might contribute to the manifestations of the ischemic microcirculatory paroxysms. Laser Doppler flowmetry with functional orthostatic and deep breathing tests contribute to the diagnosis of RP.

  17. 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.

  18. The FU Orionis Phenomenon and Solar Nebula Material

    NASA Technical Reports Server (NTRS)

    Bell, K. R.; Cassen, P. M.; Wasson, J. T.; Woolum, D. S.

    2001-01-01

    We summarize astronomical, meteoritic, and theoretical evidence relating to the FU Orionis phenomenon. This evidence suggests that at early times (the first few 10(exp 5) yr), the solar nebula experienced a hot phase characterized by high accretion rates (the "FU Ori epoch"), punctuated by episodic outbursts of enhanced mass flow through the inner part of the disk (less than or equal to 0.3 AU). Throughout this epoch, disk midplane temperatures exceeded 1000 K at 1 AU. Diminishing infall from the cloud core led to decreasing mass flux throughout the disk. When mass flow de creased below the value critical for outburst (5 x 10(exp -7) solar mass/yr, as suggested by thermal ionization instability models), outbursts ceased and the T Tauri epoch began. Outburst timescales are too long to explain calcium- and aluminum-rich inclusion (CAI) and chondrule formation. Volatility-dependent fractionation patterns seen in meteoritic materials suggest that solids formed beginning during a hot epoch when temperatures exceeded 1400 K, and the presence of volatiles in chondrites argues that this process continued until the nebula had cooled to below 400 K. The thermal ionization instability model for FU Ori outbursts is in quantitative agreement with astronomical observations. Its results imply that the terrestrial region of the nebula reached the hot end of this range only during a time when mass flow through the disk was high enough to trigger outbursts (i.e., the FU Ori epoch) and reached the cool end of this range only during the later T Tauri epoch. According to the models, heating of material in the terrestrial planet region during individual FU Ori outbursts would be limited to surface layers of the nebula, leaving midplane materials (which are at greater than or equal to 1000 K) largely unaffected. Alternative FU Ori models should be developed, particularly if compositional differences among chondrite clans are attributable to episodic heating.

  19. Renin-angiotensin system mediators and Raynaud's phenomenon.

    PubMed

    Wood, Heidi M; Ernst, Michael E

    2006-11-01

    To review the use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) in the treatment of Raynaud's phenomenon (RP). Biomedical literature was accessed through July 2006 via PubMed, the Iowa Drug Information System (IDIS), and Cumulative Index to Nursing and Allied Health Literature (CINAHL) Plus. PubMed database terms included Raynaud's disease, angiotensin-converting enzyme inhibitors, and angiotensin II type 1 receptor blockers [pharmacological action]; IDIS terms included hypotensive agents-ace inhib 24080200, raynaud's syndrome 443.0, and hypotensive agents-angioten II 24080400; and CINAHL Plus terms included Raynaud's disease, angiotensin-converting enzyme inhibitors, losartan, and irbesartan. All clinical trials published in English that reported both subjective and objective outcomes of efficacy were reviewed. Several small, short-term studies have evaluated captopril, enalapril, and losartan in the treatment of RP. The studies of ACE inhibitors have found conflicting results in their ability to improve digit blood flow and reduce both frequency and severity of RP attacks. Two studies have focused on the use of losartan for RP treatment, with both finding a statistically significant reduction in attacks and one showing improvement in symptoms of RP in comparison with the commonly utilized calcium-channel blocker, nifedipine. Most of the studies were short term (< or =12 wk) and included a limited number of patients (<60). ACE inhibitors and ARBs may provide some minor benefits in the relief of RP, although no definite evidence exists to suggest that they are superior to traditionally used treatments such as calcium-channel blockers. Larger, randomized controlled trials of longer duration are needed to compare the effectiveness of ACE inhibitors and ARBs with conventional treatment.

  20. Validation of the phenomenon of autistic regression using home videotapes.

    PubMed

    Werner, Emily; Dawson, Geraldine

    2005-08-01

    To date, there has been no objective validation of the phenomenon of autistic regression early in life. To validate parental report of autistic regression using behavioral data coded from home videotapes of children with autism spectrum disorder (ASD) vs typical development taken at 12 and 24 months of age. Home videotapes of 56 children's first and second birthday parties were collected from parents of young children with ASD with and without a reported history of regression and typically developing children. Child behaviors were coded by raters blind to child diagnosis and regression history. A parent interview that elicited information about parents' recall of early symptoms from birth was also administered. Participants were recruited from a multidisciplinary study of autism conducted at a major university. Fifteen children with ASD with a history of regression, 21 children with ASD with early-onset autism, and 20 typically developing children and their parents participated. Observations of children's communicative, social, affective, repetitive behaviors, and toy play coded from videotapes of the toddlers' first and second birthday parties. Analyses revealed that infants with ASD with regression show similar use of joint attention and more frequent use of words and babble compared with typical infants at 12 months of age. In contrast, infants with ASD with early onset of symptoms and no regression displayed fewer joint attention and communicative behaviors at 12 months of age. By 24 months of age, both groups of toddlers with ASD displayed fewer instances of word use, vocalizations, declarative pointing, social gaze, and orienting to name as compared with typically developing 24-month-olds. Parent interview data suggested that some children with regression displayed difficulties in regulatory behavior before the regression occurred. This study validates the existence of early autistic regression.

  1. 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. Published by

  2. Detection of early endothelial damage in patients with Raynaud's phenomenon.

    PubMed

    Gualtierotti, Roberta; Ingegnoli, Francesca; Griffini, Samantha; Grovetti, Elena; Borghi, Maria Orietta; Bucciarelli, Paolo; Meroni, Pier Luigi; Cugno, Massimo

    2017-09-01

    Raynaud's phenomenon (RP) can be the first manifestation of systemic sclerosis (SSc) or other connective tissue diseases (CTDs), often preceding an overt disease by years. It is not known if markers of endothelial damage are detectable in those RP patients who subsequently develop a CTD. We studied 82 RP patients at their first evaluation to correlate the levels of endothelial markers with the subsequent development of an overt disease 36months later. We measured plasma levels of tissue-type plasminogen activator (t-PA) and von Willebrand factor (vWF), two markers of endothelial damage, and interleukin-6 (IL-6), a pro-inflammatory cytokine. Thirty sex- and age-matched healthy subjects (HS) served as controls. At baseline, 67 patients showed capillaroscopic normal pattern (CNP) and 15 patients, of which 11 were very early SSc, had capillaroscopic scleroderma pattern (CSP). Plasma levels of t-PA, vWF and IL-6 were higher in patients with CNP (p=0.0001) than in HS and even much higher in patients with CSP (p=0.0001). In patients with CNP and RP of recent onset (<18months), vWF plasma levels were higher when autoantibodies were present (p=0.020). After 36months, among 48 RP patients with CNP who remained in follow-up, 24 were diagnosed as primary and 24 as secondary RP. In secondary RP, basal levels of t-PA, IL-6 and particularly vWF were higher than in primary RP (p=0.005, p=0.004, p=0.0001 respectively) and HS (p=0.0001 for all). Our findings indicate that markers of endothelial damage are elevated in RP patients who subsequently develop SSc or other CTDs, even in the absence of capillaroscopic abnormalities. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Contact dermatitis after temporary henna tattoos--an increasing phenomenon.

    PubMed

    Läuchli, S; Lautenschlager, S; Läuchl, S

    2001-04-07

    Four patients developed contact dermatitis to black henna tattoos on holiday in the Middle East and Asia. Two to ten days after skin painting an itchy, reddish swelling developed at the site of the tattoo exactly following its sharply demarcated borders. Histological investigation of the lesions revealed spongiotic dermatitis with dense lymphohistiocytic infiltrates. Patch testing in all patients showed a strong reaction to p-phenylenediamine (PPD). The other tests, including standard series and henna powder, were all negative. Healing time after application of topical class III and IV steroids was prolonged. These reports show an impressive side effect of temporary tattoos with possible long-term damage. Rather than henna, the causative agent in the pastes used for temporary tattoos appears to be PPD, a widely used dye that is added to the pastes in high concentrations to produce a darker shade. The growing incidence of this complication requires close observation, while practitioners should be aware of this sensitisation and of possible subsequent allergic reactions, especially after hair colouring with dyes based on PPD.

  4. Compressible, diffusive, reactive flow simulations of the double Mach reflection phenomenon

    NASA Astrophysics Data System (ADS)

    Ziegler, J. L.; Deiterding, R.; Shepherd, J. E.; Pullin, D. I.

    2010-11-01

    We describe direct numerical simulations of the multi-component, compressible, reactive Navier-Stokes equations in two spatial dimensions. The simulations utilize a hybrid, WENO/centered-difference numerical method, with low numerical dissipation, high-order shock-capturing, and structured adaptive mesh refinement (SAMR). These features enable resolution of diffusive processes within reaction zones. A series of one- and two-dimensional test problems are used to verify the implementation, specifically the high-order accuracy of the diffusion terms, including a viscous shock wave, the decaying Lamb-Oseen vortex, laminar flame and unstable ZND detonation. High-resolution simulations are discussed of the reactive double Mach reflection phenomenon. The diffusive scales (shear/mixing/boundary layers and flame thicknesses) and weak shocks are resolved while the strong shocks emanating from the triple points are captured. Additionally, a minimally reduced chemistry and transport model for hydrocarbon detonation is used to accurately capture the induction time, chemical relaxation, and the diffusive mixing within vortical structures evolving from the triple-point shear layer.

  5. 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

  6. 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.

  7. Local hyperhemia to heating is impaired in secondary Raynaud's phenomenon

    PubMed Central

    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 hyperhemia 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 hyperhemia 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 hyperhemia, 0.4 mg sublingual nitroglycerin challenge and thermal hyperhemia were performed using laser Doppler flowmetry on the distal pad of the third left finger. In a second study, thermal hyperhemia was performed in 10 patients with rheumatoid arthritis and 10 patients with primary RP. The thermal hyperhemia 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°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 hyperhemia was more sensitive and specific than post-occlusive hyperhemia for differentiating SSc from primary RP. In patients with rheumatoid arthritis, thermal hyperhemia was also altered in terms of amplitude. Thermal hyperhemia is dramatically altered in patients with secondary RP in comparison with subjects with primary RP. Further studies are

  8. 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

  9. The mixed chemistry phenomenon in Galactic Bulge PNe

    NASA Astrophysics Data System (ADS)

    Perea-Calderón, J. V.; García-Hernández, D. A.; García-Lario, P.; Szczerba, R.; Bobrowsky, M.

    2009-02-01

    Aims: We investigate the dual-dust chemistry phenomenon in planetary nebulae (PNe) and discuss reasons for its occurrence, by analyzing Spitzer/IRS spectra of a sample of 40 Galactic PNe among which 26 belong to the Galactic Bulge (GB). Methods: The mixed chemistry is derived from the simultaneous detection of Polycyclic Aromatic Hydrocarbon (PAH) features in the 6-14 μm range and crystalline silicates beyond 20 μm in the Spitzer/IRS spectra. Results: Out of the 26 planetary nebulae observed in the Galactic Bulge, 21 show signatures of dual-dust chemistry. Our observations reveal that the simultaneous presence of oxygen and carbon-rich dust features in the infrared spectra of [WC]-type planetary nebulae is not restricted to late/cool [WC]-type stars, as previously suggested in the literature, but is a common feature associated with all [WC]-type planetary nebulae. Surprisingly, we found that the dual-dust chemistry is seen also in all observed weak emission-line stars (wels), as well as in other planetary nebulae with central stars being neither [WC] nor wels. Most sources observed display crystalline silicate features in their spectra, with only a few PNe exhibiting, in addition, amorphous silicate bands. Conclusions: We appear to detect a recent change of chemistry at the end of the Asymptotic Giant Branch (AGB) evolution in the low-mass, high-metallicity population of GB PNe observed. The deficit of C-rich AGB stars in this environment suggests that the process of PAH formation in PNe occurs at the very end of the AGB phase. In addition, the population of low-mass, O-rich AGB stars in the Galactic Bulge, do not exhibit crystalline silicate features in their spectra. Thus, the high detection rate of dual-dust chemistry that we find cannot be explained by long-lived O-rich (primordial or circumbinary) disks. Our most plausible scenario is a final thermal pulse on the AGB (or just after), which could produce enhanced mass loss, capable of removing

  10. 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

  11. "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.

  12. [Injuries and vital reactions patterns in hanging].

    PubMed

    2015-01-01

    Hanging is a form of ligature strangulation in which the force applied to the neck is derived from the gravitational drag of one's own body weight. A furrow-dessication is the most common form of ligature mark on the skin. The furrow is a postmortem phenomenon due to ligature pressure and it is more detectable as the suspension time becomes longer.Vital reaction is a phenomenon that shows if the injury was pre- mortal. Vital signs could be present at the injury site, thus it is termed as local, but they could also be remote from the injury site, and then they are termed general vital signs. The presence and recognition of any vital reaction in each pathoforensic case indicate vitality of certain injury, which is sometimes exceptionally useful in solving the case under investigation. Although in cases of hanging there is usually no question about the vitality of injury, this does not mean that one should not recognize the type of vital reactions and location of occurrence of these phenomena in such cases. Most often they can be also useful in the reconstruction of the mechanism. This paper presents most common vital reactions in hanging, with explanation of their underlying mechanisms, and their significance in forensic pathology is pointed out.

  13. [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.

  14. An Osteoma of the Middle Ear Presenting with the Tullio Phenomenon.

    PubMed

    Hornigold, Rachael; Pearch, Ben J; Gleeson, Michael J

    2003-05-01

    The Tullio phenomenon is an extremely rare condition in which loud noise induces a brisk vestibular response. Osteomas of the middle ear cleft are also uncommon. We report a patient with an osteoma of the middle ear cleft that became symptomatic with progressive facial palsy and mixed hearing loss. The onset was heralded by the Tullio phenomenon, which she had experienced for 10 years. The differential diagnosis of the Tullio phenomenon and the management of middle ear osteomas are discussed.

  15. 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.

  16. 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.

  17. Stigma and substance use disorders: an international phenomenon.

    PubMed

    Yang, Lawrence H; Wong, Liang Y; Grivel, Margaux M; Hasin, Deborah S

    2017-09-01

    To collect and update published information on the stigma associated with substance abuse in nonclinical samples, which has not been recently reviewed. Searching large databases, a total of only 17 articles were published since 1999, with the majority of studies conducted outside the United States. Using major stigma concepts from a sociological framework (stereotyping, devaluation in terms of status loss, discrimination, and negative emotional reactions), the studies reviewed predominantly indicated that the public holds very stigmatized views toward individuals with substance use disorders (SUDs), and that the level of stigma was higher toward individuals with SUDs than toward those with other psychiatric disorders. The prevalence of SUDs is increasing in the US general population, but these disorders remain seriously undertreated. Stigma can reduce willingness of policymakers to allocate resources, reduce willingness of providers in nonspecialty settings to screen for and address substance abuse problems, and may limit willingness of individuals with such problems to seek treatment. All of these factors may help explain why so few individuals with SUDs receive treatment. Public education that reduces stigma and provides information about treatment is needed.

  18. Keratosis spinulosa developing in borderline-tuberculoid lesions during type I lepra reaction: two case reports.

    PubMed

    Thankappan, T P; Sulochana, G

    1991-03-01

    Two cases of borderline-tuberculoid leprosy which developed keratosis spinulosa over the anaesthetic areas alone during type I lepra reactions are described. Both patients only developed spiny papules during the period of reaction and subsided with control of the reaction. The probable mechanism of this peculiar phenomenon might be due to the generation of epidermal growth factors by local T cell activation during the type I lepra reaction.

  19. Some aspects of the kinetics of heterogeneous catalytic reactions

    SciTech Connect

    Golodets, G.I.; Il`chenko, N.I.; Dolgikh, L.Yu.

    1995-01-01

    An approach to developing a chemical kinetic model for heterogeneous catalytic reactions was elaborated for the case when in the course of the catalytic interaction of various gases, the adsorption of one of them (an electron donor) is promoted under the action of the other (an electron acceptor). This phenomenon is referred to as the effect of stimulating induced surface heterogeneity.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  1. Viewer Reactions to Content and Presentational Format of Television News.

    ERIC Educational Resources Information Center

    Behnke, Ralph R.; Miller, Phyllis

    1992-01-01

    Investigates patterns of college-student reactions to local television newscasts. Finds that significant audience adaptation does not occur during a 30-minute newscast and that there was no relationship between segment placement and level of viewer interest. Suggests that the audience rebound phenomenon overcomes the audience adaptation phenomenon…

  2. 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)

  3. 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) ...

  4. 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)

  5. 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) ...

  6. [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.

  7. 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…

  8. 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…

  9. 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.

  10. 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)

  11. 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…

  12. 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…

  13. Can Death Be Postponed? The Death-Dip Phenomenon in Psychiatric Patients.

    ERIC Educational Resources Information Center

    Greiner, Teresa; Pokorny, Alex D.

    1990-01-01

    Explored death-dip phenomenon, previously reported decrease in death occurring before significant dates, with cohort of 4,800 psychiatric patients. Compared dates of death with each individual's birthday, Christmas, and New Year's Day. Found no death-dip phenomenon, significant increase in accidental death preceding birthdays, suggested suicide…

  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. 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.

  16. Normobaric hypoxia overnight impairs cognitive reaction time.

    PubMed

    Pramsohler, Stephan; Wimmer, Stefan; Kopp, Martin; Gatterer, Hannes; Faulhaber, Martin; Burtscher, Martin; Netzer, Nikolaus Cristoph

    2017-05-15

    Impaired reaction time in patients suffering from hypoxia during sleep, caused by sleep breathing disorders, is a well-described phenomenon. High altitude sleep is known to induce periodic breathing with central apneas and oxygen desaturations, even in perfectly healthy subjects. However, deficits in reaction time in mountaineers or workers after just some nights of hypoxia exposure are not sufficiently explored. Therefore, we aimed to investigate the impact of sleep in a normobaric hypoxic environment on reaction time divided by its cognitive and motoric components. Eleven healthy non acclimatized students (5f, 6m, 21 ± 2.1 years) slept one night at a simulated altitude of 3500 m in a normobaric hypoxic room, followed by a night with polysomnography at simulated 5500 m. Preexisting sleep disorders were excluded via BERLIN questionnaire. All subjects performed a choice reaction test (SCHUHFRIED RT, S3) at 450 m and directly after the nights at simulated 3500 and 5500 m. We found a significant increase of cognitive reaction time with higher altitude (p = 0.026). No changes were detected in movement time (p = n.s.). Reaction time, the combined parameter of cognitive- and motoric reaction time, didn't change either (p = n.s.). Lower SpO2 surprisingly correlated significantly with shorter cognitive reaction time (r = 0.78, p = 0.004). Sleep stage distribution and arousals at 5500 m didn't correlate with reaction time, cognitive reaction time or movement time. Sleep in hypoxia does not seem to affect reaction time to simple tasks. The component of cognitive reaction time is increasingly delayed whereas motoric reaction time seems not to be affected. Low SpO2 and arousals are not related to increased cognitive reaction time therefore the causality remains unclear. The fact of increased cognitive reaction time after sleep in hypoxia, considering high altitude workers and mountaineering operations with overnight stays, should be further investigated.

  17. False negative hepatitis B surface antigen detection in dialysis patients due to excess surface antigen: postzone phenomenon.

    PubMed Central

    Hefter, L G; Hix, M A; Stoner, M; Cook, C B

    1980-01-01

    Renal dialysis patients are well known to have a high incidence of hepatitis B carrier state. In studying a group of 63 long-term dialysis patients, 10 were found to be positive for hepatitis B surface antigen by radioimmunoassay (RIA). Surprisingly, however, only three of these RIA positive patients were positive by counter immunoelectrophoresis (CIEP). The discrepancy could not be accounted for by the difference in sensitivity of the two methods. The cause for the negative reactions by CIEP in seven patients was found to be the marked excess surface antigen in these sera which produced false negative results by the postzone phenomenon. After dilution all seven sera were positive by CIEP, requiring a dilution up to 1/20 to produce a positive result. Also, all seven sera were positive by the less sensitive Ouchterlony double diffusion. Images p994-a PMID:6776153

  18. 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.

  19. 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…

  20. 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…

  1. 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.

  2. [Reactions to food].

    PubMed

    Halvorsen, R; Eggesb M; Botten, G

    1995-12-10

    Adverse reactions to food occur in about 1-2% of the population, but are reported more frequently by patients. Most reactions to food are not caused by allergy. IgE-mediated food reactions are well known and of major clinical significance owing to their potentially dangerous, even life-threatening character. Adverse reactions to food can also be caused by immunological mechanisms other than IgE-mediated reactions such as, enzyme deficiencies, active pharmacological substances in food and psychological mechanisms. Double-blind provocation is the only way to diagnose a positive reaction to a food item with some certainty. Regretably no objective measures for food reactions exist.

  3. [Predictors of no-reflow phenomenon after primary percutaneous coronary intervention].

    PubMed

    Rivera-Linares, Bernardo M; Bedolla-Barajas, Martín; Morales-Romero, Jaime; Jiménez-Gómez, J Eugenio

    2014-01-01

    No-reflow phenomenon is a common event in patients with acute myocardial infarction with ST elevation (STEMI) who underwent primary percutaneous coronary intervention. The objective is to determine the cumulative incidence of no-reflow phenomenon and some predictors related to its occurrence. We retrospectively analyzed the reports of 71 patients with STEMI. Subjects were categorized in two groups, those with no-reflow phenomenon and those without it; their clinical findings were compared. Predictive factors were identified by logistic regression analysis. We identified 20 patients with no-reflow phenomenon (with a cumulative incidence of 28.1 %) and 51 with adequate reperfusion. In the univariate analysis the following predictors were related to the no-reflow phenomenon: CK-MB = 160 UI/L, Killip class = II, TIMI flow 0, having more than two Q waves in ECG, the form of reperfusion therapy and the presence of intracoronary thrombus. The multivariate logistic regression analysis identified Killip class = II (OR = 9.3, p = 0.008), = two Q waves in ECG (OR = 1.8, p = 0.05), angioplasty as unique reperfusion therapy (OR = 19.9, p = 0.017) and the presence of intracoronary thrombus (OR = 11.9, p = 0.008) as predictors of no-reflow phenomenon. The early detection of predictors of no-reflow phenomenon will establish measures aimed to reduce its presentation.

  4. A longitudinal study on Raynaud's phenomenon in workers using an impact wrench.

    PubMed

    Aiba, Yoko; Yamamoto, Kenya; Ohshiba, Satoshi; Ikeda, Kazuhiro; Morioka, Ikuharu; Miyashita, Kazuhisa; Shimizu, Hidesuke

    2012-01-01

    The purpose of this study was to clarify the occurrence of Raynaud's phenomenon among workers using an impact wrench for a long time. The subjects were 704 workers regularly using an impact wrench and taking special medical examinations for vibration syndrome from 1981 to 2008. Raynaud's phenomenon was observed in 39 subjects during the observation period. The mean operating years at the occurrence of Raynaud's phenomenon was 25.5 ± 8.3 (standard deviation) yr. The mean total operating time (geometric average) at the occurrence of Raynaud's phenomenon was 11,689 h. By the person-year method, the incidence rate of Raynaud's phenomenon was 6.27 persons per 1,000 person-years. The estimated risk of developing Raynaud's phenomenon did not increase until 12 years after starting to operate an impact wrench but increased exponentially after that. The vibration level of an impact wrench (from 4.9 m/s(2) to 22.6 m/s(2)) exceeded the occupational exposure limit value (4.9 m/s(2)). Various countermeasures, such as introducing automatically apparatus and keeping the working environment warm to protect from cold exposure, were taken at the factory. These findings showed that the rate of occurrence of Raynaud's phenomenon was not high, although the vibration level of the impact wrench was high. This may result from various countermeasures to prevent the occurrence of Raynaud's phenomenon. A long period of exposure to vibration had the potential to lead to the occurrence of Raynaud's phenomenon even under various countermeasures.

  5. 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.

  6. 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.

  7. [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.

  8. 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.

  9. 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)

  10. Spatio-temporal Talbot phenomenon using metamaterial composite right/left-handed leaky-wave antennas

    NASA Astrophysics Data System (ADS)

    Gómez-Díaz, J. S.; Alvarez-Melcon, A.; Gupta, S.; Caloz, C.

    2008-11-01

    A spatial-temporal Talbot phenomenon, based on metamaterial composite right/left-handed (CRLH) leaky-wave antennas (LWAs), is presented. This phenomenon, reported in the microwave domain, is based on the combination of the conventional spatial monochromatic Talbot effect and the transient (polychromatic) character of the pulse radiation phenomenon in the LWA structure. When the elements of a periodic CRLH LWA array are fed simultaneously by an input pulse, the spatial beams corresponding to different temporal frequencies constructively interfere in space so as to form a self-imaged pattern constituted by narrow Talbot zones. This Talbot effect is spatial-temporal since the Talbot zones are localized both in space and time. The phenomenon is analyzed theoretically and validated numerically for the case of narrow-band pulses.

  11. Inverse Bell’s Phenomenon: Rare Ophthalmic Finding Following Ptosis Surgery

    PubMed Central

    Jakkal, Tapan; Khaire, Bhasakar

    2015-01-01

    Bell’s phenomenon is protective reflex in which the globe is turned upwards and slightly outwards during the eyelid closure to avoid corneal exposure. In Inverse Bell’s phenomenon, the eye moves downward instead of upward, this may be seen in the normal population, patients with Bell’s palsy or following conjunctival scarring. We hereby present the unusual complication of transient inversion of Bell’s phenomenon following extensive levator resection surgery performed for congenital ptosis. A 24-year-old male was undergone ptosis correction surgery. On postoperative day two, ocular examination revealed down rolling of eye ball during eyelid closure. It underwent spontaneous resolution within four weeks without any corneal complication. The patients were given frequent lubricating eye drops during this period and advised frequent follow-up for early diagnosis of corneal complication. Here we highlight an inverse Bell’s phenomenon following levator resection surgery, its possible mechanism and risk of corneal complication. PMID:25954644

  12. 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.

  13. 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

  14. Elucidation of a Peculiar Phenomenon of Voltage Measuring at a Substation

    NASA Astrophysics Data System (ADS)

    Takafuji, Kouya; Satou, Takashi; Itou, Hisanori; Kouda, Isao; Haba, Toshiaki; Satake, Atushi; Haginomori, Eiichi

    An automatic fault-recorder installed in a substation of Chubu Electric Power Company detected a peculiar phenomenon that bus-bar voltage fell to around 20-30% of the nominal value for a short time (about 8-10 cycles) though electric current didn't change during the period. The phenominon was recorded several times. In this paper, we analyzed the origin of this phenomenon and conducted simulations by EMTP. As a result, we estimated that this phenomenon occurred by the saturation of VT (voltage transformer), and this saturation caused by lightning strokes to the transmission line with line arresters, which have been increasingly installed in recent years. Moreover, we evaluated the influence of the phenomenon to protection relays.

  15. How-to-Do-It: Using the Muscle Response Phenomenon to Enhance Biology Teaching.

    ERIC Educational Resources Information Center

    Kendler, Barry S.

    1989-01-01

    Presents a method which introduces biology students to some fundamental aspects of scientific methodology. Explains simple muscle testing procedures, a historical perspective, experimental variables, pedagogical uses, and possible mechanisms of the muscle response phenomenon action. (RT)

  16. '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.

  17. 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.

  18. Relation of Nailfold Capillaries and Autoantibodies to Mortality in Patients With Raynaud Phenomenon.

    PubMed

    Mueller, Markus; Gschwandtner, Michael E; Gamper, Jutta; Giurgea, Georgiana-Aura; Charwat-Resl, Silvia; Kiener, Hans P; Smolen, Josef S; Perkmann, Thomas; Koppensteiner, Renate; Schlager, Oliver

    2016-02-02

    In incipient Raynaud phenomenon, nailfold capillaroscopy and autoantibody tests are obtained to screen for an emerging connective tissue disease. Whether the presence of abnormal nailfold capillaries and autoantibodies are related to mortality in patients with incipient Raynaud phenomenon is not known. In 2958 consecutive patients (78% women, median age 45 years) with incipient Raynaud phenomenon without previously known connective tissue disease, nailfold capillaroscopy and laboratory tests for antinuclear antibodies (ANA) and ANA subsets were obtained at initial presentation. During a median follow-up period of 9.3 years, 227 women (9.9% of female patients) and 129 men (20% of male patients) with Raynaud phenomenon died. In comparison with a demographically matched standard population, survival was poorer in patients with Raynaud phenomenon (log-rank test P<0.0001). In patients with Raynaud phenomenon, mortality was higher in men than in women (P<0.0001, Cox proportional hazards model). In women, the presence of abnormal nailfold capillaries, ANA, and anti-Scl-70 antibodies were related to an increase in all-cause mortality. The conjoint presence of abnormal nailfold capillaries and autoantibodies was associated with the highest mortality rates. In men, abnormal nailfold capillaries, and ANA and ANA subsets, as well, were not related to survival. In both sexes, patients' age and serum creatinine were associated with mortality. In Raynaud phenomenon, male sex, age, and serum creatinine are related to mortality. Abnormal nailfold capillaries and autoantibodies are associated with an increase in all-cause mortality in female patients, but not in male patients with Raynaud phenomenon. © 2016 American Heart Association, Inc.

  19. 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."

  20. Solving Cracking Phenomenon in Premium Transparent Toilet Soap Production Using Stretched LLDPE Film Wrap

    NASA Astrophysics Data System (ADS)

    Mat Sharif, Zainon Binti; Taib, Norhasnina Binti Mohd; Yusof, Mohd Sallehuddin Bin; Rahim, Mohammad Zulafif Bin; Tobi, Abdul Latif Bin Mohd; Othman, Mohd Syafiq Bin

    2017-05-01

    Cracking phenomenon in soap production is an imminent problem. It renders the soap aesthetically unpleasing. This study attempts to find best solution to solve cracking phenomenon in premium soap production. The adopted approach is a stamping method with stretched LLDPE wrap film. The result shows that stretched LLDPE wrap film able to solve the cracking problem. The appearance of the premium transparent was improved. This paper presents the results and the SOP for stretched LLDPE film wrap for soap making industries to adopt.