563 research outputs found
Comportamento e controle do gafanhoto RHAMMATOCERUS SCHISTOCERCOIDES (REHN, 1906) no Mato Grosso.
- Ern setembro de 1984, verificou-se uma explosão populacional da especie do gafanhoto Rhammatocerus schistocercoides (Rehn, 1906) no estado de Mato Grosso. 0 estudo da biologia em condicoes de laboratorio, casa de vegetario e campo revelou que a postura ocorre ern outubro-novembro e as ninfas emergern ern novembro-dezembro. Cada instar tem, em media, 26 dias, havendo cinco instares nas condicoes de Mato Grosso e seis instares nas condicoes do Distrito Federal. Transformarn-se ern adultos ern abril, n-ligratn ern agosto-setembro, e o acasalamento ocorre em setembro-outubro. Preferência alimentar: 0 R. schistocercoides prefere, ern primeiro lugar, gramineas nativas do cerrado e campo sujo, seguindo-se as culturas de arroz, cana-de-acucar, milho, sorgo, pastagens e, por firn, soja e feijão. Controle quimico: Foram testados para, o Controle do gafanhoto adulto os inseticidas: fenitrothion, malathion, carbaril, esfenvarelate e fenvarelate. 0 carbaril e os piretroides não foram eficientes nas clonagens testadas. 0 fenitrothion e o malathion mostraram acima de 98% da eficiencia nas dosagens de 300 g do i.a. e 800 g do i.a. por ha, respectivamente. Posteriormente se testou o fenitrothion dflufdo ern 61eo de algodão (50%), mostrando uma eficiência de 95% na dosagern de 150 g do La. por ha.Título em inglês: Behavior and control of the locust RHAMMATOCERUS SCHISTOCERCOIDES (REHN, 1906) in Mato Grosso, Brazil
The ultra-dense, interacting environment of a dual AGN at z 3.3 revealed by JWST/NIRSpec IFS
LBQS 0302-0019 is a blue quasar (QSO) at z ~ 3.3, hosting powerful outflows,
and residing in a complex environment consisting of an obscured AGN candidate,
and multiple companions, all within 30 kpc in projection. We use JWST NIRSpec
IFS observations to characterise the ionized gas in this complex system. We
develop a procedure to correct for the spurious oscillations (or 'wiggles') in
NIRSpec single-spaxel spectra, due to the spatial under-sampling of the point
spread function. We perform a quasar-host decomposition with the QDeblend3D
tools, and use multi-component kinematic decomposition of the optical emission
line profiles to infer the physical properties of the emitting gas. The
quasar-host decomposition allows us to identify i) a low-velocity component
possibly tracing a warm rotating disk, with a dynamical mass Mdyn Msun and a rotation-to-random motion ratio /; ii) a spatially unresolved ionised outflow, with a velocity of 1000
km/s and an outflow mass rate of Msun/yr. We also detect eight
interacting companion objects close to LBQS 0302-0019. Optical line ratios
confirm the presence of a second, obscured AGN at kpc of the primary
QSO; the dual AGN dominates the ionization state of the gas in the entire
NIRSpec field-of-view. This work has unveiled with unprecedented detail the
complex environment of this dual AGN, which includes nine interacting
companions (five of which were previously unknown), all within 30 kpc of the
QSO. Our results support a scenario where mergers can trigger dual AGN, and can
be important drivers for rapid early SMBH growth.Comment: 23 pages, 23 figures; accepted for publication by A&
GA-NIFS: JWST/NIRSpec IFU observations of HFLS3 reveal a dense galaxy group at z~6.3
Massive, starbursting galaxies in the early Universe represent some of the
most extreme objects in the study of galaxy evolution. One such source is HFLS3
(z~6.34), which was originally identified as an extreme starburst galaxy with
mild gravitational magnification. Here, we present new observations of HFLS3
with the JWST/NIRSpec IFU in both low (PRISM/CLEAR; R~100) and high spectral
resolution (G395H/290LP; R~2700), with high spatial resolution (~0.1") and
sensitivity. Thanks to the combination of the NIRSpec data and a new lensing
model with accurate spectroscopic redshifts, we find that the 3"x3" field is
crowded, with a lensed arc (C, z=6.3425+/-0.0002), two galaxies to the south
(S1 and S2, z=6.3592+/-0.0001), two galaxies to the west (W1,
z=6.3550+/-0.0001; W2, z=6.3628+/-0.0001), and two low-redshift interlopers
(G1, z=3.4806+/-0.0001; G2, z=2.00+/-0.01). We present spectral fits and
morpho-kinematic maps for each bright emission line (e.g., [OIII]5007, Halpha,
[NII]6584) from the R2700 data for all sources except G2. From a line ratio
analysis, the galaxies in C are likely powered by star formation, while we
cannot rule out or confirm the presence of AGN in the other high-redshift
sources. We perform gravitational lens modelling, finding evidence for a
two-source composition of the lensed central object and a comparable
magnification factor (mu=2.1-2.4) to previous work. The projected distances and
velocity offsets of each galaxy suggest that they will merge within the next
~1Gyr. Finally, we examine the dust extinction-corrected SFR of each z>6
source, finding that the total star formation (460+/-90 Msol/yr,
magnification-corrected) is distributed across the six z~6.34-6.36 objects over
a region of diameter ~11kpc. Altogether, this suggests that HFLS3 is not a
single starburst galaxy, but instead is a merging system of star-forming
galaxies in the Epoch of Reionization.Comment: 23 pages, 14 figures, submitted to A&
GA-NIFS: co-evolution within a highly star-forming galaxy group at z=3.7 witnessed by JWST/NIRSpec IFS
We present NIRSpec IFS observations of a galaxy group around the massive
GS_4891 galaxy at z=3.7 in GOODS-South that includes two other two systems,
GS_4891_n to the north and GS_28356 to the east. These observations, obtained
as part of the GTO GA-NIFS program, allow for the first time to study the
spatially resolved properties of the interstellar medium (ISM) and ionized gas
kinematics of a galaxy at this redshift. Leveraging the wide wavelength range
spanned with the high-dispersion grating (with resolving power R=2700)
observations, covering from [OII]3726,29 to
[SII]6716,31, we explore the spatial distribution of
star-formation rate, nebular attenuation and gas metallicity, together with the
mechanisms responsible for the excitation of the ionized gas. GS_4891 presents
a clear gradient of gas metallicity (as traced by 12 + log(O/H)) by more than
0.2dex from the south-east (where a star-forming clump is identified) to the
north-west. The gas metallicity in the less-massive northern system, GS_4891_n,
is also higher by 0.2 dex than at the center of GS_4891, suggesting that
inflows of lower-metallicity gas might be favoured in higher-mass systems. The
kinematic analysis shows that GS_4891 presents velocity gradients in the
ionized gas consistent with rotation. The region between GS_4891 and GS_4891_n
does not present high gas turbulence which, together with the difference in gas
metallicities, suggests that these two systems might be in a pre-merger stage.
Finally, GS_4891 hosts an ionized outflow that extends out to r_out=1.2 kpc
from the nucleus and reaches maximum velocities v_out of approximately 400
km/s. Despite entraining an outflowing mass rate of M_out2Msun/yr, the
low associated mass-loading factor, =0.05, implies that the outflow does
not have a significant impact on the star-formation activity of the galaxy.Comment: Submitted to Astronomy & Astrophysics on September 25th, 202
A Taxonomy of Causality-Based Biological Properties
We formally characterize a set of causality-based properties of metabolic
networks. This set of properties aims at making precise several notions on the
production of metabolites, which are familiar in the biologists' terminology.
From a theoretical point of view, biochemical reactions are abstractly
represented as causal implications and the produced metabolites as causal
consequences of the implication representing the corresponding reaction. The
fact that a reactant is produced is represented by means of the chain of
reactions that have made it exist. Such representation abstracts away from
quantities, stoichiometric and thermodynamic parameters and constitutes the
basis for the characterization of our properties. Moreover, we propose an
effective method for verifying our properties based on an abstract model of
system dynamics. This consists of a new abstract semantics for the system seen
as a concurrent network and expressed using the Chemical Ground Form calculus.
We illustrate an application of this framework to a portion of a real
metabolic pathway
Consequences of converting graded to action potentials upon neural information coding and energy efficiency
Information is encoded in neural circuits using both graded and action potentials, converting between them within single neurons and successive processing layers. This conversion is accompanied by information loss and a drop in energy efficiency. We investigate the biophysical causes of this loss of information and efficiency by comparing spiking neuron models, containing stochastic voltage-gated Na+ and K+ channels, with generator potential and graded potential models lacking voltage-gated Na+ channels. We identify three causes of information loss in the generator potential that are the by-product of action potential generation: (1) the voltage-gated Na+ channels necessary for action potential generation increase intrinsic noise and (2) introduce non-linearities, and (3) the finite duration of the action potential creates a ‘footprint’ in the generator potential that obscures incoming signals. These three processes reduce information rates by ~50% in generator potentials, to ~3 times that of spike trains. Both generator potentials and graded potentials consume almost an order of magnitude less energy per second than spike trains. Because of the lower information rates of generator potentials they are substantially less energy efficient than graded potentials. However, both are an order of magnitude more efficient than spike trains due to the higher energy costs and low information content of spikes, emphasizing that there is a two-fold cost of converting analogue to digital; information loss and cost inflation
JWST NIRCam + NIRSpec: Interstellar medium and stellar populations of young galaxies with rising star formation and evolving gas reservoirs
We present an interstellar medium and stellar population analysis of three spectroscopically confirmed z > 7 galaxies in the Early Release Observations JWST/NIRCam and JWST/NIRSpec data of the SMACS J0723.3-7327 cluster. We use the Bayesian spectral energy distribution-fitting code PROSPECTOR with a flexible star formation history (SFH), a variable dust attenuation law, and a self-consistent model of nebular emission (continuum and emission lines). Importantly, we self-consistently fit both the emission line fluxes from JWST/NIRSpec and the broad-band photometry from JWST/NIRCam, taking into account slit-loss effects. We find that these three z=7.6-8.5 galaxies (M-* approximate to 10(8) M-circle dot) are young with rising SFHs and mass-weighted ages of 3-4 Myr, though we find indications for underlying older stellar populations. The inferred gas-phase metallicities broadly agree with the direct metallicity estimates from the auroral lines. The galaxy with the lowest gas-phase metallicity (Z(gas) = 0.06 Z(circle dot)) has a steeply rising SFH, is very compact ( <0.2 kpc), and has a high star formation rate surface density (Sigma(SFR) approximate to 22 M-circle dot yr(-1) kpc(-2)), consistent with rapid gas accretion. The two other objects with higher gas-phase metallicities show more complex multicomponent morphologies on kpc scales, indicating that their recent increase in star formation rate is driven by mergers or internal, gravitational instabilities. We discuss effects of assuming different SFH priors or only fitting the photometric data. Our analysis highlights the strength and importance of combining JWST imaging and spectroscopy for fully assessing the nature of galaxies at the earliest epochs
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