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Search Results: 1 - 10 of 224168 matches for " R. Steinberg "
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Chooz and Perry: New Experiments for Long Baseline Reactor Neutrino Oscillations
R. I. Steinberg
Physics , 1993,
Abstract: We discuss the Chooz experiment, a long baseline search for neutrino vacuum oscillations, which will utilize a large gadolinium-loaded liquid scintillation detector one km from a large nuclear power station in France. The 300-meter (water equivalent) underground site of the detector reduces cosmic ray muons, the main source of background in this type of experiment, by a factor of 300, thereby allowing clean detection of antineutrinos from the reactor. The experimental goal is to probe \Delta m^2 values down to 1E-3 eV^2 for large values of sin^2 2\theta and mixing angles to 0.08 for favorable regions of \Delta m^2. A subsequent experiment which will have a 13 km baseline at the former IMB site in Ohio and which can reach \Delta m^2 = 8E-5 eV^2 is also briefly described.
A Mathematically Creative Four-Year-Old—What Do We Learn from Him?  [PDF]
Ruti Steinberg
Creative Education (CE) , 2013, DOI: 10.4236/ce.2013.47A1004
Abstract:

A 4-year-old child, who is very interested and precocious in mathematics, was interviewed doing mathematical tasks in order to find out how advanced can a 4-year-old child be? His mathematical knowledge and ability are very high. Danny was able to count objects and add them, memorizing many of the addition facts. He was able to check if numbers are even or odd. He solved a variety of challenging addition, subtraction and multiplication problems. He could read and write large numbers in hundreds and thousands and could add large numbers. Analysis was done on the kind of problems the child was able to solve, their level of difficulty and the solution strategies the child used in light of what children usually do to solve these problems in ages 5-8 (Carpenter et al., 1999). Danny also showed creativity, including inventing problems for himself to solve and finding mathematical situations in his environment to attend to. An analysis was done on the creative components of his solutions and problem posing using the literature on creativity and creativity in mathematics learning (Leikin & Pitta-Pantazi, 2013). Interview with his mother showed that she supports Danny’s mathematical development by being responsive to his initiations and allowing him to explore his ideas autonomously. Her support was discussed in light of different support patterns of parents and what kind of support is especially beneficial to the child and encourages creativity (Leder, 1992). I discuss implications for education with an emphasis on what kindergarten and school can do to promote problem solving and creativity in mathematics.

Using spirometry results in occupational medicine and research: Common errors and good practice in statistical analysis and reporting
Wagner N,Beckett W,Steinberg R
Indian Journal of Occupational and Environmental Medicine , 2006,
Abstract: Spirometry appears to be a simple and inexpensive method to measure disorders of the respiratory tract. In reality however, a simple spirometry test requires knowledge and skill to correctly conduct and evaluate the test and its results. This review addresses common misunderstandings in using, evaluating and reporting spirometry results in Occupational Health practice, clinical medicine and research. Results of spirometry need to be evaluated in relation to reference values. The factory medical officer has to decide first whether the test was technically correctly executed and is acceptable for medical interpretation. The next step is to compare results of the individual to published reference values. A 10% reduction of reference values for North Indians and Pakistanis and a 12 to 13% reduction for South Indians is recommended when Caucasian reference tables are used. In occupational health practice the worker′s spirometry performance over time needs to be considered. Common errors in reporting summarized results, for instance from groups of workers, are the incorrect use of tests of significance and incorrect presentation of aggregated spirometry results. The loss of respiratory function is recommended as an indicator of difference between two groups. That way, early changes in function can seen without waiting for a drop of function below the usually used 80%-of-predicted limit. This procedure increases the sensitivity of medical surveillance. In research the more precise Lower Limit of Normal should be calculated and used. Correct reference equations, good patient coaching, decision on the technical quality (acceptability) of each spirometry test and critical re-evaluation of the machine′s readout are essential parts of a correct spirometry test. A good understanding how results are calculated is crucial for further statistical evaluation.
Analytical Modeling of Vibration of Micropolar Plates  [PDF]
Lev Steinberg, Roman Kvasov
Applied Mathematics (AM) , 2015, DOI: 10.4236/am.2015.65077
Abstract: This paper presents an extension of mathematical static model to dynamic problems of micropolar elastic plates, recently developed by the authors. The dynamic model is based on the generalization of Hellinger-Prange-Reissner (HPR) variational principle for the linearized micropolar (Cosserat) elastodynamics. The vibration model incorporates high accuracy assumptions of the micropolar plate deformation. The computations predict additional natural frequencies, related with the material microstructure. These results are consistent with the size-effect principle known from the micropolar plate deformation. The classic Mindlin-Reissner plate resonance frequencies appear as a limiting case for homogeneous materials with no microstructure.
Utilización de variables citogenéticas y antropométricas para un eficiente manejo de primates neotropicales en cautiverio Use of cytogenetic and anthropometric variables for an efficient management of Neotropical Primates in captivity
D Ferre,E. R Steinberg,L Albarracín,A Pedrosa
InVet , 2009,
Abstract: Los monos neotropicales de la colección del Zoológico de la Ciudad de Mendoza (ZMA), Argentina, fueron objeto de un estudio colaborativo que incluyó la toma de medidas antropométricas y el análisis citogenético básico (alfa). Se estudiaron 13 ejemplares del género Alouatta sp. (10 hembras y 3 machos), 2 Cebus sp. (una hembra y un macho) y 3 hembras Saimiri sp. Mediante la cariología se confirmó que los Cebus del ZMA se corresponderían con C. paraguayanus (2N=54, XX/XY) y los Saimiri, con Saimiri boliviensis boliviensis (2N= 44,XX). En los aulladores se corroboró su asignación de especie como A. caraya y se observó una morfología cromosómica, compatible con el ya descrito sistema de determinación sexual múltiple X1X1X2X2/X1X2Y1Y2. La oportunidad permitió que el ZMA implementara por primera vez la identificación de los ejemplares a través de la colocación de microchips numerados que permitirán su seguimiento y manejo en el tiempo. The neotropical primates which are part of the collection of the Mendoza Zoological Garden (ZMA) were object of a collaborative study that included the performance of anthropometrical measurements and classic cytogenetic analysis (alpha). Thirteen specimens of the genus Alouatta (10 females and 3 males), 2 Cebus sp. (1 male and 1 female) and 3 females of Saimiri sp. were studied. The karyological study allowed to confirm that the Cebus of ZMA corresponded to Cebus paraguayanus (2N=54, XX/XY) and the Saimiri to Saimiri boliviensis boliviensis species (2N = 44, XX). In the howler monkeys the species assignment was confirmed to A. caraya and a chromosomal morphology in the mitotic metaphases, compatible with the previously described and confirmed by meiosis, multiple sex determination system X1X1X2X2/X1X2Y1Y2, was observed. This opportunity allowed the ZMA to implementthe identification through the injection of numerated microchips that will facilitate its following and management.
Do Clouds Save the Great Barrier Reef? Satellite Imagery Elucidates the Cloud-SST Relationship at the Local Scale
Susannah M. Leahy, Michael J. Kingsford, Craig R. Steinberg
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0070400
Abstract: Evidence of global climate change and rising sea surface temperatures (SSTs) is now well documented in the scientific literature. With corals already living close to their thermal maxima, increases in SSTs are of great concern for the survival of coral reefs. Cloud feedback processes may have the potential to constrain SSTs, serving to enforce an “ocean thermostat” and promoting the survival of coral reefs. In this study, it was hypothesized that cloud cover can affect summer SSTs in the tropics. Detailed direct and lagged relationships between cloud cover and SST across the central Great Barrier Reef (GBR) shelf were investigated using data from satellite imagery and in situ temperature and light loggers during two relatively hot summers (2005 and 2006) and two relatively cool summers (2007 and 2008). Across all study summers and shelf positions, SSTs exhibited distinct drops during periods of high cloud cover, and conversely, SST increases during periods of low cloud cover, with a three-day temporal lag between a change in cloud cover and a subsequent change in SST. Cloud cover alone was responsible for up to 32.1% of the variation in SSTs three days later. The relationship was strongest in both El Ni?o (2005) and La Ni?a (2008) study summers and at the inner-shelf position in those summers. SST effects on subsequent cloud cover were weaker and more variable among study summers, with rising SSTs explaining up to 21.6% of the increase in cloud cover three days later. This work quantifies the often observed cloud cooling effect on coral reefs. It highlights the importance of incorporating local-scale processes into bleaching forecasting models, and encourages the use of remote sensing imagery to value-add to coral bleaching field studies and to more accurately predict risks to coral reefs.
Preparation of pure and mixed polarization qubits and the direct measurement of figures of merit
R. B. A. Adamson,L. K. Shalm,A. M. Steinberg
Physics , 2006, DOI: 10.1103/PhysRevA.75.012104
Abstract: Non-classical joint measurements can hugely improve the efficiency with which certain figures of merit of quantum systems are measured. We use such a measurement to determine a particular figure of merit, the purity, for a polarization qubit. In the process we highlight some of subtleties involved in common methods for generating decoherence in quantum optics.
Vertical pairing of identical particles suspended in the plasma sheath
V. Steinberg,R. Sütterlin,A. V. Ivlev,G. Morfill
Physics , 2001, DOI: 10.1103/PhysRevLett.86.4540
Abstract: It is shown experimentally that vertical pairing of two identical microspheres suspended in the sheath of a radio-frequency (rf) discharge at low gas pressures (a few Pa), appears at a well defined instability threshold of the rf power. The transition is reversible, but with significant hysteresis on the second stage. A simple model, which uses measured microsphere resonance frequencies and takes into account besides Coulomb interaction between negatively charged microspheres also their interaction with positive ion wake charges, seems to explain the instability threshold quite well.
Cytoplasmic Fungal Lipases Release Fungicides from Ultra-Deformable Vesicular Drug Carriers
Gero Steinberg
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0038181
Abstract: The Transfersome? is a lipid vesicle that contains membrane softeners, such as Tween 80, to make it ultra-deformable. This feature makes the Transfersome? an efficient carrier for delivery of therapeutic drugs across the skin barrier. It was reported that TDT 067 (a topical formulation of 15 mg/ml terbinafine in Transfersome? vesicles) has a much more potent antifungal activity in vitro compared with conventional terbinafine, which is a water-insoluble fungicide. Here we use ultra-structural studies and live imaging in a model fungus to describe the underlying mode of action. We show that terbinafine causes local collapse of the fungal endoplasmic reticulum, which was more efficient when terbinafine was delivered in Transfersome? vesicles (TFVs). When applied in liquid culture, fluorescently labeled TFVs rapidly entered the fungal cells (T1/2~2 min). Entry was F-actin- and ATP-independent, indicating that it is a passive process. Ultra-structural studies showed that passage through the cell wall involves significant deformation of the vesicles, and depends on a high concentration of the surfactant Tween 80 in their membrane. Surprisingly, the TFVs collapsed into lipid droplets after entry into the cell and the terbinafine was released from their interior. With time, the lipid bodies were metabolized in an ATP-dependent fashion, suggesting that cytosolic lipases attack and degrade intruding TFVs. Indeed, the specific monoacylglycerol lipase inhibitor URB602 prevented Transfersome? degradation and neutralized the cytotoxic effect of Transfersome?-delivered terbinafine. These data suggest that (a) Transfersomes deliver the lipophilic fungicide Terbinafine to the fungal cell wall, (b) the membrane softener Tween 80 allows the passage of the Transfersomes into the fungal cell, and (c) fungal lipases digest the invading Transfersome? vesicles thereby releasing their cytotoxic content. As this mode of action of Transfersomes is independent of the drug cargo, these results demonstrate the potential of Transfersomes in the treatment of all fungal diseases.
Influencia de un factor geográfico en la potencia del rocuronio: Comparación con otro país
Steinberg,David;
Gaceta Médica de Caracas , 2008,
Abstract: ethnic differences in sensitivity to muscle relaxants have been described, both among animal species andpatients around all continents. the present trial assesses the potency for rocuronium by using data coming from a group of patients from university of nijmegen, the netherlands and a strictly comparable local one. single dose rocuronium was administered to bothgroups (n = 26 e/a) and blockade assessed. from the regression line for their log-probit transformation, slope of the curve was obtained and effective doses50, 90 and 95 for each subject calculated. sample size and power for statistical significance were estimated. a restrictive testwas performed and original data also predicted. non significant differences were noticed among the anthropometric features, mean doses and blockade achieved in both groups. neither was for effective doses: ed50= 216±47 [198-234] and 220±73 [192-248] μg.kg-1 (mean ± standard deviation, and 95 % confidence limits), ed90= 356±77 [326-386] and 320±106 [279-360] and ed95= 422±92 [387-458] and 363±120 [316-409], with a variability coefficient of 0.218 and 0.332 respectively. predictions for block were 78 % and 84 % in comparisonto actual values of 75.9 % and 70.6 % respectively. froma restrictive assay 62.66 and 62.33 % blockade were obtained. non statistical differences were shown on rocuronium?s potency (de50, 90, 95) between local patients and those from the netherlands. comparisons includingown author?s results are not different. the present trial does not support any change in rocuronium potency due to such a geographic factor.
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