6,087 research outputs found
Insect Diversity of the Lower Montane Evergreen Forest of the Western Andes Mountain Range: Cascada Chilicay and Suncamal
Biological research in the low montane evergreen forests of Ecuador focuses on ecological and botanical aspects, while knowledge of the entomofauna of these areas is almost nil. In February 2022, sampling was carried out during the dry season for 15 days, using direct and indirect capture methods (tapping, sieving, and light traps) in two waterfalls of the low montane evergreen forest of the western Andean Cordillera: Chilicay and Suncamal waterfalls, with the objective of identifying the composition of the terrestrial insect fauna at the family level. Two orders and 21 families were recorded, among which the families Carabidae and Noctuidae represented the highest percentage of the total abundance. Although preliminary, this work constitutes the first contribution to the knowledge of the entomofauna of this ecosystem.
Keywords: biodiversity, conservation, entomofauna, insects.
Resumen
Las investigaciones biológicas en los bosques siempreverdes montanos bajos de Ecuador, se centran en aspectos ecológicos y botánicos, mientras que el conocimiento de la entomofauna de estas zonas es escaso. En febrero de 2022, en la época seca y durante 15 días, utilizando métodos de captura directa e indirecta (golpeteo, tamizado y trampas de luz), se realizaron muestreos en dos cascadas del Bosque siempreverde montano bajo de la cordillera occidental de los Andes: Cascada Chilicay y Suncamal, con el objetivo de identificar la composición de la fauna de insectos terrestres a nivel de familia. Se registraron dos órdenes y 21 familias, entre las cuales, las familias Carabidae y Noctuidae representaron el mayor porcentaje de la abundancia total. Aunque en forma preliminar, este trabajo constituye el primer aporte al conocimiento de la entomofauna de este ecosistema.
Palabras Clave: Biodiversidad, conservación, entomofauna, insectos
Star formation in low density HI gas around the Elliptical Galaxy NGC2865
Interacting galaxies surrounded by HI tidal debris are ideal sites for the
study of young clusters and tidal galaxy formation. The process that triggers
star formation in the low-density environments outside galaxies is still an
open question. New clusters and galaxies of tidal origin are expected to have
high metallicities for their luminosities. Spectroscopy of such objects is,
however, at the limit of what can be done with existing 8-10m class telescopes,
which has prevented statistical studies of these objects. NGC2865 is an
UV-bright merging elliptical galaxy with shells and extended HI tails. The
regions observed in this work were previously detected using multi-slit imaging
spectroscopy. We obtain new multislit spectroscopy of six young star-forming
regions around NGC2865, to determine their redshifts and metallicities. The six
emission-line regions are located 16-40 kpc from NGC2865 and they have similar
redshifts. They have ages of ~10Myears and an average metallicity of
12+log(O/H) ~ 8.6, suggesting a tidal origin for the regions. It is noted that
they coincide with an extended HI tail, which has projected density of N
< 10 cm, and displays a low surface brightness counterpart. These
regions may represent the youngest of the three populations of star clusters
already identified in NGC2865. The high, nearly-solar, oxygen abundances found
for the six regions in the vicinity of NGC2865 suggest that they were formed by
pre-enriched material from the parent galaxy, from gas removed during the last
major merger. Given the mass and the location of the HII regions, we can
speculate that these young star-forming regions are potential precursors of
globular clusters that will be part of the halo of NGC2865 in the future. Our
result supports the use of the multi-slit imaging spectroscopy as a useful tool
for finding nearly-formed stellar systems around galaxies.Comment: 7 pages, 2 figures accepted in A&
K^0-\bar{K}^0 mixing in the Standard Model from Nf=2+1+1 Twisted Mass Lattice QCD
We present preliminary results at {\beta} = 1.95 (a = 0.077 fm) on the first
unquenched N_f=2+1+1 lattice computation of the B_K parameter which controls
the neutral kaon oscillations in the Standard Model. Using N_f=2+1+1 maximally
twisted sea quarks and Osterwalder-Seiler valence quarks we achieve O(a)
improvement and a continuum-like renormalization pattern for the four-fermion
operator. Our results are extrapolated/interpolated to the physical
light/strange quark mass but not yet to the continuum limit. The computation of
the relevant renormalization constants is performed non perturbatively in the
RI'-MOM scheme using dedicated simulations with N_f=4 degenerate sea quark
flavours produced by the ETM collaboration.
We get B_K^{RGI} (a = 0.077) = 0.747(18), which when compared to our previous
unquenched N_f=2 determination and most of the existing results, suggests a
rather weak B_K^{RGI} dependence on the number of dynamical flavours. We are at
the moment analysing lattice data at two additional {\beta} values which will
allow us to perform an extrapolation to the continuum limit.Comment: 7 pages, 8 figures, Proceedings of Lattice 2011, XXIX International
Symposium on Lattice Field Theory, Squaw Valley, Lake Tahoe, Californi
A determination of the average up-down, strange and charm quark masses from
We present a lattice QCD determination of the average up-down, strange and
charm quark masses based on simulations performed by the European Twisted Mass
Collaboration with dynamical fermions. We simulated at three
different values of the lattice spacing, the smallest being approximately
, and with pion masses as small as . Our results are:
,
, ,
and
B-physics from lattice QCD...with a twist
We present a precise lattice QCD determination of the b-quark mass, of the B
and Bs decay constants and first results for the B-meson bag parameters. For
our computation we employ the so-called ratio method and our results benefit
from the use of improved interpolating operators for the B-mesons. QCD
calculations are performed with Nf = 2 dynamical light-quarks at four values of
the lattice spacing and the results are extrapolated to the continuum limit.
The preliminary results are mb(mb) = 4.35(12) GeV for the MSbar b-quark mass,
fBs = 234(6) MeV and fB = 197(10) MeV for the B-meson decay constants, BBs(mb)
= 0.90(5) and BB(mb) = 0.87(5) for the B-meson bag parameters.Comment: 6 pages, 3 figures. Proceedings of the 36th International Conference
on High Energy Physics - ICHEP 2012; July 4-11 2012; Melbourne, Australi
Should We Learn Probabilistic Models for Model Checking? A New Approach and An Empirical Study
Many automated system analysis techniques (e.g., model checking, model-based
testing) rely on first obtaining a model of the system under analysis. System
modeling is often done manually, which is often considered as a hindrance to
adopt model-based system analysis and development techniques. To overcome this
problem, researchers have proposed to automatically "learn" models based on
sample system executions and shown that the learned models can be useful
sometimes. There are however many questions to be answered. For instance, how
much shall we generalize from the observed samples and how fast would learning
converge? Or, would the analysis result based on the learned model be more
accurate than the estimation we could have obtained by sampling many system
executions within the same amount of time? In this work, we investigate
existing algorithms for learning probabilistic models for model checking,
propose an evolution-based approach for better controlling the degree of
generalization and conduct an empirical study in order to answer the questions.
One of our findings is that the effectiveness of learning may sometimes be
limited.Comment: 15 pages, plus 2 reference pages, accepted by FASE 2017 in ETAP
B-physics from the ratio method with Wilson twisted mass fermions
We present a precise lattice QCD determination of the b-quark mass, of the B
and Bs decay constants and first preliminary results for the B-mesons bag
parameter. Simulations are performed with Nf = 2 Wilson twisted mass fermions
at four values of the lattice spacing and the results are extrapolated to the
continuum limit. Our calculation benefits from the use of improved
interpolating operators for the B-mesons and employs the so-called ratio
method. The latter allows a controlled interpolation at the b-quark mass
between the relativistic data around and above the charm quark mass and the
exactly known static limit.Comment: 7 pages, 4 figures, 1 table. Proceedings of the 30th International
Symposium on Lattice Field Theory - Lattice 2012; June 24-29, 2012; Cairns,
Australi
Bright galaxies at Hubble's redshift detection frontier: Preliminary results and design from the redshift z~9-10 BoRG pure-parallel HST survey
We present the first results and design from the redshift z~9-10 Brightest of
the Reionizing Galaxies {\it Hubble Space Telescope} survey BoRG[z9-10], aimed
at searching for intrinsically luminous unlensed galaxies during the first 700
Myr after the Big Bang. BoRG[z9-10] is the continuation of a multi-year
pure-parallel near-IR and optical imaging campaign with the Wide Field Camera
3. The ongoing survey uses five filters, optimized for detecting the most
distant objects and offering continuous wavelength coverage from
{\lambda}=0.35{\mu}m to {\lambda}=1.7{\mu}m. We analyze the initial ~130
arcmin of area over 28 independent lines of sight (~25% of the total
planned) to search for z>7 galaxies using a combination of Lyman break and
photometric redshift selections. From an effective comoving volume of (5-25)
Mpc for magnitudes brighter than in the
-band respectively, we find five galaxy candidates at z~8.3-10
detected at high confidence (S/N>8), including a source at z~8.4 with mAB=24.5
(S/N~22), which, if confirmed, would be the brightest galaxy identified at such
early times (z>8). In addition, BoRG[z9-10] data yield four galaxies with . These new Lyman break galaxies with m are
ideal targets for follow-up observations from ground and space based
observatories to help investigate the complex interplay between dark matter
growth, galaxy assembly, and reionization.Comment: Accepted for publication on ApJ. 21 pages, 11 figures, 4 table
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