8,332 research outputs found
Conditions for the onset of the current filamentation instability in the laboratory
Current Filamentation Instability (CFI) is capable of generating strong
magnetic fields relevant to explain radiation processes in astrophysical
objects and lead to the onset of particle acceleration in collisionless shocks.
Probing such extreme scenarios in the laboratory is still an open challenge. In
this work, we investigate the possibility of using neutral
beams to explore the CFI with realistic parameters, by performing 2D
particle-in-cell simulations. We show that CFI can occur unless the rate at
which the beam expands due to finite beam emittance is larger than the CFI
growth rate and as long as the role of competing electrostatic two-stream
instability (TSI) is negligible. We also show that the longitudinal energy
spread, typical of plasma based accelerated electron-positron fireball beams,
plays a minor role in the growth of CFI in these scenarios
A Comprehensive View of a Strongly Lensed Planck-Associated Submillimeter Galaxy
We present high-resolution maps of stars, dust, and molecular gas in a strongly lensed submillimeter galaxy (SMG) at z = 3.259. HATLAS J114637.9–001132 is selected from the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS) as a strong lens candidate mainly based on its unusually high 500 μm flux density (~300 mJy). It is the only high-redshift Planck detection in the 130 deg^2 H-ATLAS Phase-I area. Keck Adaptive Optics images reveal a quadruply imaged galaxy in the K band while the Submillimeter Array and the Jansky Very Large Array show doubly imaged 880 μm and CO(1→0) sources, indicating differentiated distributions of the various components in the galaxy. In the source plane, the stars reside in three major kpc-scale clumps extended over ~1.6 kpc, the dust in a compact (~1 kpc) region ~3 kpc north of the stars, and the cold molecular gas in an extended (~7 kpc) disk ~5 kpc northeast of the stars. The emissions from the stars, dust, and gas are magnified by ~17, ~8, and ~7 times, respectively, by four lensing galaxies at z ~ 1. Intrinsically, the lensed galaxy is a warm (T_(dust) ~ 40-65 K), hyper-luminous (L_(IR) ~ 1.7 × 10^(13) L_☉; star formation rate (SFR) ~2000 M_☉ yr^(–1)), gas-rich (M_(gas)/M_(baryon) ~ 70%), young (M_(stellar)/SFR ~ 20 Myr), and short-lived (M_(gas)/SFR ~ 40 Myr) starburst. With physical properties similar to unlensed z > 2 SMGs, HATLAS J114637.9–001132 offers a detailed view of a typical SMG through a powerful cosmic microscope
Peletização de sementes de arroz.
O objetivo deste estudo foi verificar a viabilidade da peletização de sementes de arroz, sem prejuízo do poder germinativo e vigor durante o armazenamento e proporcionar adição de zinco às sementes.bitstream/CNPAF/23580/1/comt_111.pd
Correlation amplitude and entanglement entropy in random spin chains
Using strong-disorder renormalization group, numerical exact diagonalization,
and quantum Monte Carlo methods, we revisit the random antiferromagnetic XXZ
spin-1/2 chain focusing on the long-length and ground-state behavior of the
average time-independent spin-spin correlation function C(l)=\upsilon
l^{-\eta}. In addition to the well-known universal (disorder-independent)
power-law exponent \eta=2, we find interesting universal features displayed by
the prefactor \upsilon=\upsilon_o/3, if l is odd, and \upsilon=\upsilon_e/3,
otherwise. Although \upsilon_o and \upsilon_e are nonuniversal (disorder
dependent) and distinct in magnitude, the combination \upsilon_o + \upsilon_e =
-1/4 is universal if C is computed along the symmetric (longitudinal) axis. The
origin of the nonuniversalities of the prefactors is discussed in the
renormalization-group framework where a solvable toy model is considered.
Moreover, we relate the average correlation function with the average
entanglement entropy, whose amplitude has been recently shown to be universal.
The nonuniversalities of the prefactors are shown to contribute only to surface
terms of the entropy. Finally, we discuss the experimental relevance of our
results by computing the structure factor whose scaling properties,
interestingly, depend on the correlation prefactors.Comment: v1: 16 pages, 15 figures; v2: 17 pages, improved discussions and
statistics, references added, published versio
Fenologia reprodutiva de arbóreas: período de produção de frutos e sementes do açoita-cavalo.
Edição dos resumos do 18º Congresso Brasileiro de Sementes, 2013, Florianópolis. CD-ROM
Fenologia reprodutiva de arbóreas: período de produção de frutos e sementes da canela-guaica.
Edição dos resumos do 18º Congresso Brasileiro de Sementes, 2013, Florianópolis. CD-ROM
Fenologia reprodutiva: período de produção de sementes de ingá.
Edição dos resumos do 17º Congresso Brasileiro de Sementes, 2011, Natal. Resumo 1115
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