218 research outputs found
Distribution of Palinuridae and Scyllaridae phyllosoma larvae within the East Australian Current: a climate change hot spot
Many marine species are predicted to shift their ranges poleward due to rising ocean temperatures driven by climate change. For benthic marine species with pelagic larval stages, poleward range shifts are often facilitated through pelagic larval transport via western boundary currents (WBC). By surveying pelagic larval distributions within WBCs, species advected poleward of their known distributions can be identified and monitored. Palinurid and scyllarid lobster larvae (phyllosoma) have long pelagic larval durations, providing high potential for poleward advection. We surveyed spatial distribution of phyllosoma within the western-boundary East Australian Current. Due to difficulties morphologically identifying phyllosoma, we tested the utility of molecular identification using cytochrome c oxidase I (COI). From COI sequences of 56 phyllosoma and one postlarva, 65% of sequences consisted of good-quality mitochondrial DNA. Across water types sampled, scyllarid phyllosoma exhibited relatively homogeneous distribution, whereas palinurid phyllosoma exhibited heterogeneous distribution with greatest abundance inside a warm core eddy on the south coast of eastern Australia. Two tropical and one subtropical palinurid species were detected ~75–1800 km to the south or south-west of their known species distribution. Our results indicate tropical lobster species are reaching temperate regions, providing these species the opportunity to establish in temperate regions if or when environmental conditions become amenable to settlement
Tannin-Based Copolymer Resins: Synthesis and Characterization by Solid State 13C NMR and FT-IR Spectroscopy
In recent years, the interest for bio-sources is rising exponentially and tannins extracts are one of the most interesting, easily-available, phenolic building blocks. The condensed tannins or proanthocyanidins are already known for their polymerization chemistry, which is the basis for several natural-based materials (e.g., adhesives, foams). In the present work we aim to observe the behavior of the extract of Acacia Mimosa (Acacia mearnsii) when reacted with several possible co-monomers at different relative amount, pH and temperature conditions. The more insoluble copolymers obtained with formaldehyde, hexamine, glyoxal, maleic anhydride, furfural and furfuryl alcohol were analyzed through solid state 13C NMR (Nuclear magnetic resonance) and FT-IR (Fourier Transform-Infrared) spectroscopy. The 13C NMR afforded the opportunity to detect: (i) aromatic substitutions and consequent poly-condensations for the majority of the hardeners studied; (ii) acylation for the maleic anhydride and also some; (iii) Diels–Alder arrangements for the furanic co-monomers; the FT-IR spectroscopy suggested that the formaldehyde and hexamine copolymers present a higher cross-linking degree
Star formation and dust obscuration in the tidally distorted galaxy NGC 2442
Abridged: We present a detailed investigation of the morphological
distribution and level of star formation and dust obscuration in the nearby
tidally distorted galaxy NGC2442. Spitzer images in the IR at 3.6, 4.5, 5.8,
8.0um, and 24um and GALEX images at 1500\AA{} and 2300\AA{} allow us to resolve
the galaxy on scales between 240-600pc. We supplement these with archival data
in the B, J, H, and K bands. We use the 8um, 24um and FUV (1500\AA) emission to
study the star formation rate (SFR). We find that globally, these tracers of
star formation give a range of results of ~6-11\msun/yr, with the
dust-corrected FUV giving the highest value of SFR. We can reconcile the UV and
IR-based estimates by adopting a steeper UV extinction curve that lies in
between the starburst (Calzetti) and SMC extinction curves. However, the
regions of highest SFR intensity along the spiral arms are consistent with a
starburst-like extinction. Overall, the level of star-formation we find is
higher than previously published for this galaxy, by about a factor of two,
which, contrary to previous conclusions, implies that the interaction that
caused the distorted morphology of NGC2442 likely also triggered increased
levels of star-formation activity. Outside of the spiral arms, we discover what
appears to be a superbubble, ~1.7kpc across in the IRAC images. Significant
H{\alpha}, UV and IR emission in the area also suggest vigorous ongoing
star-formation. A known, recent supernova (SN1999ga) is located at the edge of
this superbubble. Although speculative at this stage, this area suggests a
large star-forming region with a morphology shaped by generations of
supernovae. Lastly, we discover an 8um (PAH) circumnuclear ring with an ~0.8kpc
radius. The H{\alpha} emission is largely concentrated inside that ring and
shows a vague spiral structure in the rest of the galaxy.Comment: 16 pages, 13 figures, accepted for publication in Ap
Advancing our understanding of the connectivity, evolution and management of marine lobsters through genetics
The genomic revolution has provided powerful insights into the biology and ecology of many non-model organisms. Genetic tools have been increasingly applied to marine lobster research in recent years and have improved our understanding of species delimitation and population connectivity. High resolution genomic markers are just beginning to be applied to lobsters and are now starting to revolutionise our understanding of fine spatial and temporal scales of population connectivity and adaptation to environmental conditions. Lobsters play an important role in the ecosystem and many species are commercially exploited but many aspects of their biology is still largely unknown. Genetics is a powerful tool that can further contribute to our understanding of their ecology and evolution and assist management. Here we illustrate how recent genetic advancements are (1) leading to a step change in our understanding of evolution and adaptation, (2) elucidating factors driving connectivity and recruitment, (3) revealing insights into ecological processes and can (4) potentially revolutionise management of this commercially important group. We discuss how improvements in sequencing technologies and statistical methods for genetic data analyses combined with increased sampling efforts and careful sampling design have transformed our understanding of lobsters biology in recent years. We also highlight possible future directions in the application of genomic tools to lobster research that can aid management, in particular, the close-kin-mark-recapture method. Finally, we identify gaps and challenges in lobster research, such as the lack of any reference genomes and predictions on how lobsters will respond to future environmental conditions
An Integrated Framework for Simulation-based Software Process Improvement
In this paper we present an integrated framework for
software process improvement according to CMM. The
framework is double-integrated. First, it is based on the
systematic integration of dynamic modules to build a
dynamic model to model each maturity level proposed in
the reference model. As a consequence, a hierarchical set
of dynamic models is developed following the same
hierarchy of levels suggested in CMM. Second, the
dynamic models of the framework are integrated with the
use of different static techniques commonly used in
planning, control, and process evaluation.
The paper describes the reasons found to follow this
approach, the integration process of models and
techniques, the implementation of the framework, and
shows an example of how it can be used in a software
process improvement regarding the cost of software
quality.CICYT TIC2001-1143-C03-0
The Type II supernovae 2006V and 2006au: two SN 1987A-like events
Supernova 1987A revealed that a blue supergiant (BSG) star can end its life
as a core-collapse supernova (SN). SN 1987A and other similar objects exhibit
properties that distinguish them from ordinary Type II Plateau (IIP) SNe, whose
progenitors are believed to be red supergiants (RSGs). Similarities among
1987A-like events include a long rise to maximum, early luminosity fainter than
that of normal Type IIP SNe, and radioactivity acting as the primary source
powering the light curves. We present and analyze two SNe monitored by the
Carnegie Supernova Project that are reminiscent of SN 1987A. Optical and
near-infrared (NIR) light curves, and optical spectroscopy of SNe 2006V and
2006au are presented. These observations are compared to those of SN 1987A, and
are used to estimate properties of their progenitors. Both objects exhibit a
slow rise to maximum and light curve evolution similar to that of SN 1987A. At
the earliest epochs, SN 2006au also displays an initial dip which we interpret
as the signature of the adiabatic cooling phase that ensues shock break- out.
SNe 2006V and 2006au are both found to be bluer, hotter and brighter than SN
1987A. Spectra of SNe 2006V and 2006au are similar to those of SN 1987A and
other normal Type II objects, although both consistently exhibit expansion
velocities higher than SN 1987A. Semi-analytic models are fit to the UVOIR
light curve of each object from which physical properties of the progenitors
are estimated. This yields ejecta mass estimates of about 20 solar masses,
explosion energies of 2 - 3 x 10^51 erg, and progenitor radii of 75 - 100 solar
radii for both SNe. The progenitors of SNe 2006V and 2006au were most likely
BSGs with a larger explosion energy as compared to that of SN 1987A.Comment: 21 pages,15 figures, accepted for publication in A&A, 25 October 201
Development of a gas chromatography - mass spectrometry method for the determination of carbon disulfide in the atmosphere
[EN] Carbon disulfide (CS2), a relevant reduced sulfur compound in air, is well-known for its malodor and its significant effect on global atmospheric chemistry. Therefore, a reliable method for determining CS2 in atmospheric samples has been developed based on solid-phase sampling and gas chromatography-mass spectrometry (GC-MS). Two types of solid-phase sampling supports (Orbo-32 and SKC) and the elution with organic solvents - hexane and toluene - were evaluated for low-volume outdoor sampling. Recovery studies and the standard addition method were carried out to demonstrate the proper determination of CS2 in the absence of the influence of interferences such as ozone, hydrogen sulfide or water - important atmospheric pollutants. The proposed methodology was validated by performing experiments in a high-volume smog chamber and by comparison with two reference optical methods, Fourier Transform Infrared (FTIR) and Differential Optical Absorption Spectroscopy (DOAS) installed in these facilities. Satisfactory analytical parameters were reported: fast analysis, a correct repeatability of 6±1% and reproducibility of 14±3%, and low detection limits of 0.3-0.9pgm-3. Finally, the method was successfully applied to industrial samples near a pulp factory area, where a high correlation between industrial emissions and reported carbon disulfide concentrations were observed. © 2011 Elsevier B.V.The research leading to these results received funding from the Centro de Investigacion del Medio Ambiente (CIMA), Consejeria de Medio Ambiente, Gobierno de Cantabria. The Instituto Universitario CEAM-UMH is partly supported by Generalitat Valenciana, Fundacion Bancaja, and the projects GRACCIE (Consolider-Ingenio 2010) and FEEDBACKS (Prometeo - Generalitat Valenciana). We also acknowledged the European Community's Seventh Framework Program under the grant agreement no. 228335 (Eurochamp2), the Spanish Ministry of Science and Innovation, through INNPLANTA project: PCT-440000-2010-003 and the EUPHORE staff for their support in the chamber experiments. The authors also thank J.T.B. for his contribution.Borrás GarcĂa, EM.; RĂłdenas, M.; Dieguez, J.; PĂ©rez-GarcĂa, M.; Lomba, R.; Lavin, J.; Tortajada-Genaro, LA. (2012). Development of a gas chromatography - mass spectrometry method for the determination of carbon disulfide in the atmosphere. Microchemical Journal. 101:37-42. https://doi.org/10.1016/j.microc.2011.10.002S374210
Peculiar Type II Supernovae from Blue Supergiants
The vast majority of Type II supernovae (SNe) are produced by red supergiants
(RSGs), but SN 1987A revealed that blue supergiants (BSGs) can produce members
of this class as well, albeit with some peculiar properties. This best studied
event revolutionized our understanding of SNe, and linking it to the bulk of
Type II events is essential. We present here optical photometry and
spectroscopy gathered for SN 2000cb, which is clearly not a standard Type II SN
and yet is not a SN 1987A analog. The light curve of SN 2000cb is reminiscent
of that of SN 1987A in shape, with a slow rise to a late optical peak, but on
substantially different time scales. Spectroscopically, SN 2000cb resembles a
normal SN II but with ejecta velocities that far exceed those measured for SN
1987A or normal SNe II, above 18000 km/s for H-alpha at early times. The red
colours, high velocities, late photometric peak, and our modeling of this
object all point toward a scenario involving the high-energy explosion of a
small-radius star, most likely a BSG, producing 0.1 solar masses of Ni-56.
Adding a similar object to the sample, SN 2005ci, we derive a rate of about 2%
of the core-collapse rate for this loosely defined class of BSG explosions.Comment: Accepted to MNRAS on March 14, 201
SN 1999ga: a low-luminosity linear type II supernova?
Type II-linear supernovae are thought to arise from progenitors that have
lost most of their H envelope by the time of the explosion, and they are poorly
understood because they are only occasionally discovered. It is possible that
they are intrinsically rare, but selection effects due to their rapid
luminosity evolution may also play an important role in limiting the number of
detections. In this context, the discovery of a subluminous type II-linear
event is even more interesting. We investigate the physical properties and
characterise the explosion site of the type II SN 1999ga, which exploded in the
nearby spiral galaxy NGC 2442. Spectroscopic and photometric observations of SN
1999ga allow us to constrain the energetics of the explosion and to estimate
the mass of the ejected material, shedding light on the nature of the
progenitor star in the final stages of its life. The study of the environment
in the vicinity of the explosion site provides information on a possible
relation between these unusual supernovae and the properties of the galaxies
hosting them. Despite the lack of early-time observations, we provide
reasonable evidence that SN 1999ga was probably a type II-linear supernova that
ejected a few solar masses of material, with a very small amount of radioactive
elements of the order of 0.01 solar masses.Comment: 11 pages, 9 figures. Accepted for publication in A&A (March 28, 2009
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