2,573 research outputs found
Magnon Condensation in a Dense Nitrogen-Vacancy Spin Ensemble
The feasibility of creating a Bose-Einstein condensate of magnons using a
dense ensemble of nitrogen-vacancy spin defects in diamond is investigated.
Through assessing a density-dependent spin exchange interaction strength and
the magnetic phase transition temperature () using the
Sherrington-Kirkpatrick model, the minimum temperature-dependent concentration
for magnetic self-ordering is estimated. For a randomly dispersed spin
ensemble, the calculated average exchange constant exceeds the average dipole
interaction strengths for concentrations approximately greater than 70 ppm,
while is estimated to exceed 10 mK beyond 90 ppm, reaching 300 K at a
concentration of approximately 450 ppm. On this basis, the existence of
dipole-exchange spin waves and their plane-wave dispersion is postulated and
estimated using a semiclassical magnetostatic description. This is discussed
along with a -based estimate of the four-magnon scattering rate, which
indicates magnons and their condensation may be detectable in thin films for
concentrations greater than 90 ppm.Comment: 14 pages, 6 figure
Blind separation of underdetermined mixtures with additive white and pink noises
This paper presents an approach for underdetermined
blind source separation in the case of additive Gaussian
white noise and pink noise. Likewise, the proposed approach is applicable in the case of separating I + 3 sources from I mixtures with additive two kinds of noises. This situation is more challenging and suitable to practical real world problems. Moreover, unlike to some conventional approaches, the sparsity conditions are not imposed. Firstly, the mixing matrix is estimated based on an algorithm that combines short time Fourier transform and rough-fuzzy clustering. Then, the mixed
signals are normalized and the source signals are recovered using modified Gradient descent Local Hierarchical Alternating Least Squares Algorithm exploiting the mixing matrix obtained from the previous step as an input and initialized by multiplicative algorithm for matrix factorization based on alpha divergence. The experiments and simulation results
show that the proposed approach can separate I + 3 source
signals from I mixed signals, and it has superior evaluation performance compared to some conventional approaches
The Minimal Set of Electroweak Precision Parameters
We present a simple method for analyzing the impact of precision electroweak
data above and below the Z-peak on flavour-conserving heavy new physics. We
find that experiments have probed about ten combinations of new physics
effects, which to a good approximation can be condensed into the effective
oblique parameters Shat, That, Uhat, V, X, W, Y (we prove positivity
constraints W, Y >= 0) and three combinations of quark couplings (including a
distinct parameter for the bottom). We apply our method to generic extra Z'
vectors.Comment: 22 pages, 3 figure
Alien Registration- Sullivan, Ella A. (Reed Plantation, Aroostook County)
https://digitalmaine.com/alien_docs/32792/thumbnail.jp
Implementing a Definition of Street Harassment at Gettysburg College
My project focuses on implementing a definition of street harassment at Gettysburg College. To do so, I plan to add the definition to the Student Code of Conduct through meetings with the Student Life Committee. In order to ensure my success in adding the definition, I will pass an opinion through the Student Senate and send out a survey through engageGettysburg to show support for the definition. By accomplishing this, I hope to make Gettysburg College a more inclusive, open, and safe environment for all students
Efficacy of emamectin benzoate, pyridalyl and methoxyfenozide on pomegranate butterfly, Virachola livia (Klug) (Lepidoptera: Lycanidae) in cultivated and reclaimed lands
The pomegranate butterfly, Virachola livia (Klug) (Lepidoptera: Lycanidae), is one of the most important pests in Egypt. Under pomegranate field conditions, the study was conducted from 2012 to 2013 to compare the efficacy of methoxyfenozide, pyridalyl and emamectin benzoate against pomegranate butterfly in cultivated and reclaimed lands at Assiut Governorate, Egypt. These insecticides demonstrated a significant low infestation of the pomegranate butterfly during 2012 and 2013 seasons compared to control field. Emamectin benzoate and pyridalyl were found to be highly effective for controlling V. livia with an average infestation of 0.33- 4.33% and 1.00- 6.67% compared to methoxyfenozide (0.33- 17.67%) in both cultivated and reclaimed lands, respectively. Data indicated that, the infestation was higher in the cultivated land than reclaimed land during 2012 and 2013 seasons. The change in temperature and relative humidity may affect the susceptibility of pomegranate fruits to the infestation by V. livia. In addition, results showed that all pomegranate trees under treated field had a significant increase in the average weight fruits by about 70-90% compared to control field. Methoxyfenozide, pyridalyl and emamectin benzoate can be considered as promising candidates to control the pomegranate butterfly, V. livia infestation in both cultivated and reclaimed lands
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