64,506 research outputs found
Completeness and Nonclassicality of Coherent States for Generalized Oscillator Algebras
The purposes of this work are (1) to show that the appropriate
generalizations of the oscillator algebra permit the construction of a wide set
of nonlinear coherent states in unified form; and (2) to clarify the likely
contradiction between the nonclassical properties of such nonlinear coherent
states and the possibility of finding a classical analog for them since they
are P-represented by a delta function. In (1) we prove that a class of
nonlinear coherent states can be constructed to satisfy a closure relation that
is expressed uniquely in terms of the Meijer G-function. This property
automatically defines the delta distribution as the P-representation of such
states. Then, in principle, there must be a classical analog for them. Among
other examples, we construct a family of nonlinear coherent states for a
representation of the su(1,1) Lie algebra that is realized as a deformation of
the oscillator algebra. In (2), we use a beam splitter to show that the
nonlinear coherent states exhibit properties like anti-bunching that prohibit a
classical description for them. We also show that these states lack second
order coherence. That is, although the P-representation of the nonlinear
coherent states is a delta function, they are not full coherent. Therefore, the
systems associated with the generalized oscillator algebras cannot be
considered `classical' in the context of the quantum theory of optical
coherence.Comment: 26 pages, 10 figures, minor changes, misprints correcte
Spectroscopic search for binaries among EHB stars in globular clusters
We performed a spectroscopic search for binaries among hot Horizontal Branch
stars in globular clusters. We present final results for a sample of 51 stars
in NGC6752, and preliminary results for the first 15 stars analyzed in M80. The
observed stars are distributed along all the HBs in the range 8000 < Teff <
32000 K, and have been observed during four nights. Radial velocity variations
have been measured with the cross-correlation technique. We carefully analyzed
the statistical and systematic errors associated with the measurements in order
to evaluate the statistical significance of the observed variations. No close
binary system has been detected, neither among cooler stars nor among the
sample of hot EHB stars (18 stars with Teff > 22000 K in NGC6752). The data
corrected for instrumental effects indicate that the radial velocity variations
are always below the 3sigma level of ~15 km/s. These results are in sharp
contrast with those found for field hot subdwarfs, and open new questions about
the formation of EHB stars in globular clusters, and possibly of the field
subdwarfs.Comment: To appear in Baltic Astronomy. Proceedings of the 2nd meeting on Hot
Subdwarf Stars, La Palma, June 2005. 4 pages, 2 figure
,
El empleo de manera gratuita y de fácil acceso, de imágenes del satélite Sentinel-2 y de productos finales de este, como NDVI, por parte de los técnicos y agricultores, y su integración en las diferentes plataformas de asesoramiento al regante, facilita la determinación del estado hídrico de la parcela, el monitoreo y detección de alertas y seguimiento de cultivos, permitiendo una rápida actuación.</p
Women architects outside the Spanish borders: patriarchal models at International Congresses (1939-1975)
In the complex political scene surrounding the death of Francisco Franco, Spanish female architects were crossing borders to try and understand what was happening abroad. This article provides unpublished data on the various experiences of female graduates in Spain when they shared their enthusiasm, concerns and energy with colleagues from other countries at international conferences that took place before the arrival of democracy. For almost four decades, between 1939 and 1975, Spanish female architects were limited by the patriarchal system's own barriers and by the political barriers imposed by Franco's regime. This paper aims to organise and articulate women's memories, proving the implicit acceptance of patriarchal ideas and models at the start of the 20th century, the timidity of the congress resolutions in the sixties and the later awakening provided by UIFA (Union Internationale des Femmes Architectes) congresses. Finally, it is worth examining the metamorphosis that occurred in free western societies in the 20th century, with respect to the role played by women as a user and as a professional, through the attentive gaze of women architects from a nondemocratic country
Peri-implantitis, systemic inflammation, and dyslipidemia: a cross-sectional biochemical study
Purpose: The aim of this study was to compare the inflammatory and lipid profile of patients with and without peri-implantitis. /
Methods: A cross-sectional biochemical study was carried out in which blood samples were collected from 16 patients with peri-implantitis and from 31 subjects with healthy implants. Clinical peri-implant parameters were obtained from all subjects. Levels of tumor necrosis factor-alpha and interleukin-10 (IL-10) were measured in serum. Lipid fractions, glucose and creatinine levels, and complete blood count were also assessed. /
Results: After controlling for a history of periodontitis, statistically significant differences between peri-implantitis patients and controls were found for total cholesterol (estimated adjusted mean difference, 76.4 mg/dL; 95% confidence interval [CI], 39.6, 113.2 mg/dL; P<0.001), low-density lipoprotein (LDL) cholesterol (estimated adjusted mean difference, 57.7 mg/dL; 95% CI, 23.8, 91.6 mg/dL; P<0.001), white blood cells (WBC) (estimated adjusted mean difference, 2.8×103/μL; 95% CI, 1.6, 4.0×103/μL; P<0.001) and IL-10 (estimated adjusted mean difference, −10.4 pg/mL; 95% CI, −15.8, −5.0 pg/mL; P<0.001). The peri- implant probing pocket depth (PPD) was modestly positively correlated with total cholesterol (r=0.512; P<0.001), LDL cholesterol (r=0.463; P=0.001), and WBC (r=0.519; P<0.001). A moderate negative correlation was observed between IL-10 and PPD (r=0.609; P<0.001). /
Cardiovascular diseases; Dyslipidemias; Peri-implantitis; Inflammation; Leukocytes
Conclusions: Otherwise healthy individuals with peri-implantitis showed increased low- grade systemic inflammation and dyslipidemia
Poor weather doesn’t dissuade voting in noncompetitive elections – not even Hurricane Sandy did in 2012
Rational choice theories of voter behavior suggest that factors such as bad weather and a busy schedule should discourage voting in noncompetitive elections. Considering voter turnout in New York City in 2012 – in the immediate aftermath of Hurricane Sandy – Viviana Rivera-Burgos, Narayani Lasala-Blanco and Robert Y. Shapiro find that personal motivation to vote can override minor and even major costs of voting, even in noncompetitive elections
Atmospheric-Pressure Non-thermal Plasma-JET effects on PS and PE surfaces
https://www.scopus.com/inward/record.url?eid=2-s2.0-84938125206&partnerID=40&md5=c2325a28f944e7e3e20b601b8d9a73efThe Atmospheric-Pressure Non-Thermal Plasma (APNTP) has become a topic of a great interest for a wide spectrum of applications in different industry branches, including the surface of treatment processes. In this work we evaluate the effect of an argon APNTP exposure to determine changes suffered by a polystyrene (PS) and polyethylene (PE) polymer surface through RAMAN spectroscopy and SEM. It was determined that the hydrophilic change in energetic terms, i.e. surface activation in the PS and PE polymers is addition of oxygen by surface activation when the samples with jet plasma are exposed with the inert argon gas. It was possible to characterize the hydrophilic shift based on the change in intensity of the spectra. © Published under licence by IOP Publishing Ltd.Ad Astra Rocket Company,Instituto Tecnologico de Costa Rica,International Atomic Energy Agency (IAEA),Universidad Nacional de Costa Ric
Abundance anomalies in hot horizontal branch stars of the Galactic globular cluster NGC 2808
Astronomy and Astrophysics, 452, pp. 493-501, http://dx.doi.org./10.1051/0004-6361:20054593International audienc
- …