1,340 research outputs found
The exotic weevil Stenopelmus rufinasus Gyllenhal, 1835 (Coleoptera: Curculionidae) across a "host-free" pond network
The presence of the exotic weevil Stenopelmus rufinasus (Coleoptera: Curculionidae) is closely related to the occurrence of
the exotic red water fern, Azolla filiculoides. In this paper, we present the first records of S. rufinasus in Doñana National
Park (SW Spain), based on sampling of macroinvertebrates in 91 temporary ponds, including monthly samples of 22 ponds,
during two successive years (2005-2007). The exotic weevil was present in 21% of the sampled ponds where the host plant, A.
filiculiodes, was not detectable. Because A. filiculoides can reach high densities in an adjacent area of marsh, we suggest that
the occurrence of the exotic weevil in these ponds is a consequence of dispersal from nearby marshes. Our study demonstrates
that S. rufinasus adults can occur at relatively high densities in ponds where the host plant is not present, suggesting that such
apparently “host-free” sites may act as stepping stones for the spread of this speciesLa presencia de la especie de gorgojo exótico Stenopelmus rufinasus (Coleoptera: Curculionidae) está íntimamente rela-
cionada con la planta acuática exótica Azolla filiculoides. En este estudio se registró por primera vez la presencia de S.
rufinasus en el Parque Nacional de Doñana (SO España) tras realizar un muestreo de macroinvertebrados en 91 lagunas
que incluye muestreos mensuales de 22 de las mismas durante dos años consecutivos (2005-2007). El gorgojo exótico estuvo
presente en el 21% de las lagunas muestreadas a pesar de que su supuesto hospedador, A. filiculiodes, no fue detectado.
Dado que A. filiculiodes puede alcanzar grandes densidades en la marisma adyacente, sugerimos que la presencia del gor-
gojo exótico en las lagunas temporales se debe a su dispersión desde la marisma. Este estudio demuestra que individuos
adultos de S. rufinasus pueden aparecer con densidades relativamente altas en lagunas donde su hospedador potencial no
está presente, lo que sugiere que estos sitios libres de hospedador podrían actuar como zonas de paso para la dispersión de
la especiePeer reviewe
The census of interstellar complex organic molecules in the Class I hot corino of SVS13-A
We present the first census of the interstellar Complex Organic Molecules
(iCOMs) in the low-mass Class I protostar SVS13-A, obtained by analysing data
from the IRAM-30m Large Project ASAI (Astrochemical Surveys At IRAM). They
consist of an high-sensitivity unbiased spectral survey at the 1mm, 2mm and 3mm
IRAM bands. We detected five iCOMs: acetaldehyde (CHCHO), methyl formate
(HCOOCH), dimethyl ether (CHOCH), ethanol (CHCHOH) and
formamide (NHCHO). In addition we searched for other iCOMs and ketene
(HCCO), formic acid (HCOOH) and methoxy (CHO), whose only ketene was
detected. The numerous detected lines, from 5 to 37 depending on the species,
cover a large upper level energy range, between 15 and 254 K. This allowed us
to carry out a rotational diagram analysis and derive rotational temperatures
between 35 and 110 K, and column densities between and
cm on the 0."3 size previously determined by
interferometric observations of glycolaldehyde. These new observations clearly
demonstrate the presence of a rich chemistry in the hot corino towards SVS13-A.
The measured iCOMs abundances were compared to other Class 0 and I hot corinos,
as well as comets, previously published in the literature. We find evidence
that (i) SVS13-A is as chemically rich as younger Class 0 protostars, and (ii)
the iCOMs relative abundances do not substantially evolve during the
protostellar phase.Comment: 24 pages, MNRAS in pres
Planetary Candidates Observed by Kepler V: Planet Sample from Q1-Q12 (36 Months)
The Kepler mission discovered 2842 exoplanet candidates with 2 years of data.
We provide updates to the Kepler planet candidate sample based upon 3 years
(Q1-Q12) of data. Through a series of tests to exclude false-positives,
primarily caused by eclipsing binary stars and instrumental systematics, 855
additional planetary candidates have been discovered, bringing the total number
known to 3697. We provide revised transit parameters and accompanying posterior
distributions based on a Markov Chain Monte Carlo algorithm for the cumulative
catalogue of Kepler Objects of Interest. There are now 130 candidates in the
cumulative catalogue that receive less than twice the flux the Earth receives
and more than 1100 have a radius less than 1.5 Rearth. There are now a dozen
candidates meeting both criteria, roughly doubling the number of candidate
Earth analogs. A majority of planetary candidates have a high probability of
being bonafide planets, however, there are populations of likely
false-positives. We discuss and suggest additional cuts that can be easily
applied to the catalogue to produce a set of planetary candidates with good
fidelity. The full catalogue is publicly available at the NASA Exoplanet
Archive.Comment: Accepted for publication, ApJ
Measuring Transit Signal Recovery in the Kepler Pipeline. III. Completeness of the Q1-Q17 DR24 Planet Candidate Catalogue, with Important Caveats for Occurrence Rate Calculations
With each new version of the Kepler pipeline and resulting planet candidate
catalogue, an updated measurement of the underlying planet population can only
be recovered with an corresponding measurement of the Kepler pipeline detection
efficiency. Here, we present measurements of the sensitivity of the pipeline
(version 9.2) used to generate the Q1-Q17 DR24 planet candidate catalog
(Coughlin et al. 2016). We measure this by injecting simulated transiting
planets into the pixel-level data of 159,013 targets across the entire Kepler
focal plane, and examining the recovery rate. Unlike previous versions of the
Kepler pipeline, we find a strong period dependence in the measured detection
efficiency, with longer (>40 day) periods having a significantly lower
detectability than shorter periods, introduced in part by an incorrectly
implemented veto. Consequently, the sensitivity of the 9.2 pipeline cannot be
cast as a simple one-dimensional function of the signal strength of the
candidate planet signal as was possible for previous versions of the pipeline.
We report on the implications for occurrence rate calculations based on the
Q1-Q17 DR24 planet candidate catalog and offer important caveats and
recommendations for performing such calculations. As before, we make available
the entire table of injected planet parameters and whether they were recovered
by the pipeline, enabling readers to derive the pipeline detection sensitivity
in the planet and/or stellar parameter space of their choice.Comment: 8 pages, 5 figures, full electronic version of Table 1 available at
the NASA Exoplanet Archive; accepted by ApJ May 2nd, 201
Chemical shifts and cluster structure
The 2p core-level electron binding energies of size-selected silicon cluster
ions have been determined from soft x-ray photoionization efficiency curves.
Local chemical shifts and global charging energy contributions to the 2p
binding energy can be separated, because core-level and valence-band electron
binding energies exhibit the same inverse radius dependence. The experimental
2p binding energy distributions show characteristic size-specific patterns
that are well reproduced by the corresponding electronic density of states
obtained from density functional theory modeling. These results demonstrate
that 2p binding energies in silicon clusters are dominated by initial state
effects, i.e., by the interaction with the local valence electron density, and
can thus be used to corroborate structural assignments
Response to comment on 'Amphibian fungal panzootic causes catastrophic and ongoing loss of biodiversity'
Lambert et al. question our retrospective and holistic epidemiological assessment of the role of chytridiomycosis in amphibian declines. Their alternative assessment is narrow and provides an incomplete evaluation of evidence. Adopting this approach limits understanding of infectious disease impacts and hampers conservation efforts. We reaffirm that our study provides unambiguous evidence that chytridiomycosis has affected at least 501 amphibian species
More than skin deep: Functional genomic basis for resistance to Amphibian Chytridiomycosis
The amphibian-killing chytrid fungus Batrachochytriumdendrobatidis (Bd) is one of themost generalist pathogens known, capable of
infecting hundreds of species globally and causing widespread population declines and extinctions. However, some host species are
seemingly unaffected by Bd, tolerating or clearing infections without clinical signs of disease. Variation in host immune responses is
commonly evoked for these resistant or tolerant species, yet to date,we have nodirect comparisonof amphibian species responses to
infection at the level of gene expression. In this study,we challenged four CentralAmerican frog species that vary in Bd susceptibility,
with a sympatric virulent strain of the pathogen. We compared skin and spleen orthologous gene expression using differential
expression tests and coexpression gene network analyses.Wefound that resistant species have reduced skin inflammatory responses
andincreased expressionofgenes involved inskin integrity. Incontrast, onlyhighly susceptible species exhibited suppressionof splenic
T-cell genes. We conclude that resistance to chytridiomycosis may be related to a species’ ability to escape the immunosuppressive
activity of the fungus. Moreover, our results indicate that within-species differences in splenic proteolytic enzyme gene expression
may contribute to intraspecific variation in survival. This first comparison of amphibian functional immunogenomic architecture in
response to Bd provides insights into key genetic mechanisms underlying variation in disease outcomes among amphibian species
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