6,004 research outputs found
Dynamics of zonal flow-like structures in the edge of the TJ-II stellarator
The dynamics of fluctuating electric field structures in the edge of the
TJ-II stellarator, that display zonal flow-like traits, is studied. These
structures have been shown to be global and affect particle transport
dynamically [J.A. Alonso et al., Nucl. Fus. 52 063010 (2012)]. In this article
we discuss possible drive (Reynolds stress) and damping (Neoclassical
viscosity, geodesic transfer) mechanisms for the associated ExB velocity. We
show that: (a) while the observed turbulence-driven forces can provide the
necessary perpendicular acceleration, a causal relation could not be firmly
established, possibly because of the locality of the Reynolds stress
measurements, (b) the calculated neoclassical viscosity and damping times are
comparable to the observed zonal flow relaxation times, and (c) although an
accompanying density modulation is observed to be associated to the zonal flow,
it is not consistent with the excitation of pressure side-bands, like those
present in geodesic acoustic oscillations, caused by the compression of the ExB
flow field
Relação folha/colmo de quatro híbridos de sorgo com capim-sudão avaliados em quatro idades de corte.
Ayotzinapa y la crisis del estado neoliberal mexicano
¿Qué pasó en Ayotzinapa? Es la pregunta que surgió el 26 de septiembre de 2014, que no encuentra una respuesta satisfactoria pese a la intervención de actores de distintas instancias, niveles y nacionalidades, y al esbozo de múltiples hipótesis sobre los enfrentamientos registrados en Iguala, Guerrero, que derivaron en la muerte de varias personas y la desaparición de 43 estudiantes de la Normal Rural “Isidro Burgos”, en una tragedia que evidenció la crisis que atraviesa el estado mexicano y que afecta a todo el país.
A partir de lo acontecido en Ayotzinapa y con base en la teoría general de los campos de Pierre Bourdieu y su propuesta de análisis teórico metodológico sobre el estado, en esta obra se realiza un análisis de la práctica sistemática y generalizada de las desapariciones forzadas en México, con el fin de ofrecer otra manera de comprender el entretejido político–económico–social que hace posible este grave fenómeno, que desgarra tanto a familias como a la comunidad.
La herida abierta por Ayotzinapa sangra y el objetivo último de este libro es contribuir a evitar que se cierre en tanto no se responda la interrogante de qué pasó ahí y que crímenes de lesa humanidad como este sigan aconteciendo en México.ITESO, A.C
Theoretical description of phase coexistence in model C60
We have investigated the phase diagram of the Girifalco model of C60
fullerene in the framework provided by the MHNC and the SCOZA liquid state
theories, and by a Perturbation Theory (PT), for the free energy of the solid
phase. We present an extended assessment of such theories as set against a
recent Monte Carlo study of the same model [D. Costa et al, J. Chem. Phys.
118:304 (2003)]. We have compared the theoretical predictions with the
corresponding simulation results for several thermodynamic properties. Then we
have determined the phase diagram of the model, by using either the SCOZA, or
the MHNC, or the PT predictions for one of the coexisting phases, and the
simulation data for the other phase, in order to separately ascertain the
accuracy of each theory. It turns out that the overall appearance of the phase
portrait is reproduced fairly well by all theories, with remarkable accuracy as
for the melting line and the solid-vapor equilibrium. The MHNC and SCOZA
results for the liquid-vapor coexistence, as well as for the corresponding
critical points, are quite accurate. All results are discussed in terms of the
basic assumptions underlying each theory. We have selected the MHNC for the
fluid and the first-order PT for the solid phase, as the most accurate tools to
investigate the phase behavior of the model in terms of purely theoretical
approaches. The overall results appear as a robust benchmark for further
theoretical investigations on higher order C(n>60) fullerenes, as well as on
other fullerene-related materials, whose description can be based on a
modelization similar to that adopted in this work.Comment: RevTeX4, 15 pages, 7 figures; submitted to Phys. Rev.
Discrete symmetries, invisible axion and lepton number symmetry in an economic 3-3-1 model
We show that Peccei-Quinn and lepton number symmetries can be a natural
outcome in a 3-3-1 model with right-handed neutrinos after imposing a Z_11 x
Z_2 symmetry. This symmetry is suitably accommodated in this model when we
augmented its spectrum by including merely one singlet scalar field. We work
out the breaking of the Peccei-Quinn symmetry, yielding the axion, and study
the phenomenological consequences. The main result of this work is that the
solution to the strong CP problem can be implemented in a natural way, implying
an invisible axion phenomenologically unconstrained, free of domain wall
formation and constituting a good candidate for the cold dark matter.Comment: 17 pages, Revtex
Measurement of the branching ratios of the decays Xi0 --> Sigma+ e- nubar and anti-Xi0 --> anti-Sigma+ e+ nu
From 56 days of data taking in 2002, the NA48/1 experiment observed 6316 Xi0
--> Sigma+ e- nubar candidates (with the subsequent Sigma+ --> p pi0 decay) and
555 anti-Xi0 --> anti-Sigma+ e+ nu candidates with background contamination of
215+-44 and 136+-8 events, respectively. From these samples, the branching
ratios BR(Xi0 --> Sigma+ e- nubar)= (2.51+-0.03stat+-0.09syst)E(-4) and
BR(anti-Xi0 --> anti-Sigma+ e+ nu)= (2.55+-0.14stat+-0.10syst)E(-4) were
measured allowing the determination of the CKM matrix element |Vus| =
0.209+0.023-0.028. Using the Particle Data Group average for |Vus| obtained in
semileptonic kaon decays, we measured the ratio g1/f1 = 1.20+-0.05 of the
axial-vector to vector form factors.Comment: 16 pages, 11 figures Submitted to Phys.Lett.
Resuscitation of Severe Uncontrolled Hemorrhage 7.5% Sodium Chloride/6% Dextran 70 vs 0.9% Sodium Chloride
Objectives: Resuscitation studies of hypertonic saline using controlled and uncontrolled hemorrhage models yield conflicting results with regard to efficacy. These disparate results reflect the use of models and resuscitation regimens that are not comparable between studies. This study evaluated the effects of comparable and clinically relevant resuscitation regimens of 7.5% sodium chloride/6% dextran 70 (HSD) and 0.9% sodium chloride (NS) in a near-fatal uncontrolled hemorrhage model. Methods: Thirty-six swine (14.2 to 21.4 kg) with 4-mm aortic tears were bled to a pulse pressure of 5 mm Hg (40-45 mL/kg). The animals were resuscitated with either NS or HSD administered in volumes that provided equivalent sodium loads at similar rates. Group II (n = 12) was resuscitated with 80 mL/kg of NS at a rate of 4 mL/kg/min. Group III (n = 12) received 9.6 mL/kg of HSD at a rate of 0.48 mL/kg/min. In both groups, crystalloid resuscitation was followed by shed blood infusion (30 mL/kg) at a rate of 2 mL/kg/min. Group I (controls; n = 12) were not resuscitated. Results: One-hour mortality was significantly greater in group I (92%) as compared with group II (33%) and group III (33%) (Fisher's exact test; p = 0.004). Intraperitoneal hemorrhage was significantly greater in group II (34 ± 20 mL/kg) and group III (31 ± 13 mL/kg) as compared with group I (5 ± 2 mL/kg) (ANOVA; p < 0.05). There was no significant difference in hemodynamic parameters between groups II and III. Conclusion: In this model of severe uncontrolled hemorrhage, resuscitation with HSD or NS, administered in volumes that provided equivalent sodium loads at similar rates, had similar effects on mortality, hemodynamic parameters, and hemorrhage from the injury site.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73625/1/j.1553-2712.2000.tb02060.x.pd
Measurement of the Ratio Gamma(KL -> pi+ pi-)/Gamma(KL -> pi e nu) and Extraction of the CP Violation Parameter |eta+-|
We present a measurement of the ratio of the decay rates Gamma(KL -> pi+
pi-)/Gamma(KL -> pi e nu), denoted as Gamma(K2pi)/Gamma(Ke3). The analysis is
based on data taken during a dedicated run in 1999 by the NA48 experiment at
the CERN SPS. Using a sample of 47000 K2pi and five million Ke3 decays, we find
Gamma(K2pi)/Gamma(Ke3) = (4.835 +- 0.022(stat) +- 0.016(syst)) x 10^-3. From
this we derive the branching ratio of the CP violating decay KL -> pi+ pi- and
the CP violation parameter |eta+-|. Excluding the CP conserving direct photon
emission component KL -> pi+ pi- gamma, we obtain the results BR(KL -> pi+ pi-)
= (1.941 +- 0.019) x 10^-3 and |eta+-| = (2.223 +- 0.012) x 10^-3.Comment: 20 pages, 7 figures, accepted by Phys. Lett.
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