5,387 research outputs found
Умови розвитку методологічної культури майбутнього вчителя у педагогіці Василя Сухомлинського
У статті висвітлюються теоретичні засади та методичні аспекти розвитку методологічної культури майбутнього вчителя у педагогічній спадщині Василя Сухомлинського. Автор акцентує увагу на дослідженні інтерпертації видатним педагогом змісту та умов формування методологічної культури як важливої характеристики професіоналізму вчителя
Observation of the Dynamical Casimir Effect in a Superconducting Circuit
One of the most surprising predictions of modern quantum theory is that the
vacuum of space is not empty. In fact, quantum theory predicts that it teems
with virtual particles flitting in and out of existence. While initially a
curiosity, it was quickly realized that these vacuum fluctuations had
measurable consequences, for instance producing the Lamb shift of atomic
spectra and modifying the magnetic moment for the electron. This type of
renormalization due to vacuum fluctuations is now central to our understanding
of nature. However, these effects provide indirect evidence for the existence
of vacuum fluctuations. From early on, it was discussed if it might instead be
possible to more directly observe the virtual particles that compose the
quantum vacuum. 40 years ago, Moore suggested that a mirror undergoing
relativistic motion could convert virtual photons into directly observable real
photons. This effect was later named the dynamical Casimir effect (DCE). Using
a superconducting circuit, we have observed the DCE for the first time. The
circuit consists of a coplanar transmission line with an electrical length that
can be changed at a few percent of the speed of light. The length is changed by
modulating the inductance of a superconducting quantum interference device
(SQUID) at high frequencies (~11 GHz). In addition to observing the creation of
real photons, we observe two-mode squeezing of the emitted radiation, which is
a signature of the quantum character of the generation process.Comment: 12 pages, 3 figure
Powers of Hamilton cycles in pseudorandom graphs
We study the appearance of powers of Hamilton cycles in pseudorandom graphs,
using the following comparatively weak pseudorandomness notion. A graph is
-pseudorandom if for all disjoint and with and we have
. We prove that for all there is an
such that an -pseudorandom graph on
vertices with minimum degree at least contains the square of a
Hamilton cycle. In particular, this implies that -graphs with
contain the square of a Hamilton cycle, and thus
a triangle factor if is a multiple of . This improves on a result of
Krivelevich, Sudakov and Szab\'o [Triangle factors in sparse pseudo-random
graphs, Combinatorica 24 (2004), no. 3, 403--426].
We also extend our result to higher powers of Hamilton cycles and establish
corresponding counting versions.Comment: 30 pages, 1 figur
An instrumented cylinder measuring pinch force and orientation
Background: The function of a cylinder allowing simultaneous measurements of the opposition axis of the index finger and thumb of the hand and the magnitude of pinch force is described.\ud
Methods: The apparatus is made of two half-cylinders that are bonded together through a 6-axis force/torque sensor and allows the measurement of 3D orthogonal forces and moments of force. The amplitude of the pinch force exerted on the cylinder by the fingers is defined as the resultant of the forces in the different axes. A software program was developed to measure the barycentre of the forces on the instrumented cylinder, allowing calculation of the angle of the opposition axis between the fingers and the location of the resulting pinch force on the cylinder, assuming that the pinch or grip forces are co-linear through the center of the cylinder.\ud
In order to assess the validity and reliability of the measurements, the cylinder was mounted on a milling table and seven calibrated weights (from 100 to 500 g) were successively applied perpendicularly to a 9*9 matrix of sites separated by 1 cm. With the exception of the extreme lateral parts of the cylinder, the dispersion of the calculated vertical position of the resulting force was always within 1 mm of the application point, suggesting a high reliability of these measurements. In addition, the errors in the angles of the applied force were calculated and found to be less than 2 degree with no clear patterns of variation across the different locations of the cylinder.\ud
Results: The usefulness of the cylinder is demonstrated by evaluating the pinch force and the opposition axis in six healthy subjects lifting the cylinder from the table using three different orientations of their right hand. The magnitude of the grip force was not significantly different across orientations (45, 22 and -22 degrees relative to the midline of the subject) suggesting that force grip is controlled.\ud
Conclusion: From these results, it has been concluded that the cylinder is a valid, reliable and precise instrument that may prove useful for evaluating opposition axis and grip force in healthy and pathological populations
Satellites of the largest Kuiper Belt objects
We have searched the four brightest objects in the Kuiper Belt for the presence of satellites using the newly commissioned Keck Observatory Laser Guide Star Adaptive Optics system. Satellites are seen around three of the four objects: Pluto (whose satellite Charon is well-known and whose recently discovered smaller satellites are too faint to be detected), 2003 EL61 (where a second satellite is seen in addition to the previously known satellite), and 2003 UB313 (where a satellite is seen for the first time). The object 2005 FY9, the brightest Kuiper Belt object (KBO) after Pluto, does not have a satellite detectable within 0".4 with a brightness of more than 1% of the primary. The presence of satellites around three of the four brightest KBOs is inconsistent with the fraction of satellites in the Kuiper Belt at large at the 99.2% confidence level, suggesting a different formation mechanism for these largest KBO satellites. The two satellites of 2003 EL61, and the one satellite of 2003 UB313, with fractional brightnesses of 5% and 1.5%, and 2%, of their primaries, respectively, are significantly fainter relative to their primaries than other known KBO satellites, again pointing to possible differences in their origin
High-resolution spectroscopy of the R Coronae Borealis and Other Hydrogen Deficient Stars
High-resolution spectroscopy is a very important tool for studying stellar
physics, perhaps, particularly so for such enigmatic objects like the R Coronae
Borealis and related Hydrogen deficient stars that produce carbon dust in
addition to their peculiar abundances.
Examples of how high-resolution spectroscopy is used in the study of these
stars to address the two major puzzles are presented: (i) How are such rare
H-deficient stars created? and (ii) How and where are the obscuring soot clouds
produced around the R Coronae Borealis stars?Comment: 16 pages, 9 figures, Astrophysics and Space Science Proceedings,
Springer-Verlag, Berlin, 201
Combination fluticasone and salmeterol versus fixed dose combination budesonide and formoterol for chronic asthma in adults and children
BackgroundCombination therapies are frequently recommended as maintenance therapy for people with asthma, whose disease is not adequately controlled with inhaled steroids. Fluticasone/salmeterol (FP/SAL) and budesonide/formoterol (BUD/F) have been assessed against their respective monocomponents, but there is a need to compare these two therapies on a head-to-head basis.ObjectivesTo estimate the relative effects of fluticasone/salmeterol and budesonide/formoterol in terms of asthma control, safety and lung function.Search strategyWe searched the Cochrane Airways Group register of trials with prespecified terms. We performed additional hand searching of manufacturers' web sites and online trial registries. Searches are current to May 2008.Selection criteriaRandomised studies comparing fixed dose FP/SAL and BUD/ F were eligible, for a minimum of 12 weeks. Crossover studies were excluded. Our primary outcomes were: i) exacerbations requiring oral steroid bursts, ii) hospital admission and iii) serious adverse events.Data collection and analysisTwo authors independently assessed studies for inclusion in the review. We combined continuous data outcomes with a mean difference (MD), and dichotomous data outcomes with an odds ratio (OR).Main resultsFive studies met the review entry criteria (5537 participants). Primary outcomes: The odds of an exacerbation requiring oral steroids did not differ significantly between treatments (OR 0.89; 95% CI 0.73 to 1.09, three studies, 4515 participants). The odds of an exacerbation leading hospital admission were also not significantly different (OR 1.29; 95% CI 0.68 to 2.47, four studies, 4879 participants). The odds of serious adverse events did not differ significantly between treatments (OR 1.47; 95% CI 0.75, 2.86, three studies, 4054 participants). Secondary outcomes: Lung function outcomes, symptoms, rescue medication, exacerbations leading ED visit/hospital admission and adverse events were not significantly different between treatments.Authors' conclusionsThe evidence in this review indicates that differences in the requirement for oral steroids and hospital admission between BUD/F and FP/SAL do not reach statistical significance. However, the confidence intervals do not exclude clinically important differences between treatments in reducing exacerbations or causing adverse events. The width of the confidence intervals for the primary outcomes justify further trials in order to better determine the relative effects of these drug combinations. Although this review sought to assess the effects of these drugs in both adults and children, no trials were identified in the under-12s and research in this area is of a high priority
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Early Observations And Analysis Of The Type Ia SN 2014J In M82
We present optical and near infrared (NIR) observations of the nearby Type Ia SN 2014J. Seventeen optical and 23 NIR spectra were obtained from 10 days before (-10d) to 10 days after (+10d) the time of maximum B-band brightness. The relative strengths of absorption features and their patterns of development can be compared at one day intervals throughout most of this period. Carbon is not detected in the optical spectra, but we identify C I lambda 1.0693 in the NIR spectra. Mg II lines with high oscillator strengths have higher initial velocities than other Mg II lines. We show that the velocity differences can be explained by differences in optical depths due to oscillator strengths. The spectra of SN 2014J show that it is a normal SN Ia, but many parameters are near the boundaries between normal and high-velocity subclasses. The velocities for OI, Mg II, Si II, S Ca a, and Fell suggest that SN 2014J has a layered structure with little or no mixing. That result is consistent with the delayed detonation explosion models. We also report photometric observations, obtained from -10d to +29d, in the UBVRIJH and K-s bands. The template fitting package SNooPy is used to interpret the light curves and to derive photometric parameters. Using R-v = 1.46, which is consistent with previous studies, SNooPy finds that A(v) = 1.80 for E(B - V)(host) = 1.23 +/- 0.06 mag. The maximum B-band brightness of -19.19 +/- 0.10 mag was reached on February 1.74 UT +/- 0.13 days and the supernova has a decline parameter, Delta m(15), of 1.12 +/- 0.02 mag.Department of Space, Government of IndiaHungarian OTKA NN-107637NSF AST-1109801, AST-1151462, AST-1211196NSF Astronomy and Astrophysics Postdoctoral Fellowship AST-1302771NASA through a grant from the Space Telescope Science Institute GO-12540NASA NAS5-26555Swedish Research CouncilSwedish National Space BoardDanish Agency for Science and Technology and Innovation realized through a Sapere Aude Level 2 grantAstronom
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