66 research outputs found
Satellite Tracking of Manta Rays Highlights Challenges to Their Conservation
We describe the real-time movements of the last of the marine mega-vertebrate taxa to be satellite tracked – the giant manta ray (or devil fish, Manta birostris), the world's largest ray at over 6 m disc width. Almost nothing is known about manta ray movements and their environmental preferences, making them one of the least understood of the marine mega-vertebrates. Red listed by the International Union for the Conservation of Nature as ‘Vulnerable’ to extinction, manta rays are known to be subject to direct and incidental capture and some populations are declining. Satellite-tracked manta rays associated with seasonal upwelling events and thermal fronts off the Yucatan peninsula, Mexico, and made short-range shuttling movements, foraging along and between them. The majority of locations were received from waters shallower than 50 m deep, representing thermally dynamic and productive waters. Manta rays remained in the Mexican Exclusive Economic Zone for the duration of tracking but only 12% of tracking locations were received from within Marine Protected Areas (MPAs). Our results on the spatio-temporal distribution of these enigmatic rays highlight opportunities and challenges to management efforts
Prevalencia de trastorno por déficit de atención e hiperactividad en niños y niñas con retraso mental de bucaramanaga, Colombia
ResumenAntecedentes: En niños y niñas con retraso mental (RM) son frecuentes los sintomas de desatención, hiperactividad e impulsibilidad. Sin embargo, no se conoce la prevalencia de trastorno por déficit de atención e hiperactividad (TDAH) en niños y niñas con RM.[Matínes SJ, Remolina LM, Picón AA, Gómez LF, Campo Arias A. Prevalencia de trastorno por déficit de atención e hiperactividad en niños y niñas con retraso mental de bucaramanaga, Colombia. MedUNAB 2004; 7:157-60].Palbras clave: Trastorno por déficit de atención e hiperactividad, prevalencia, retraso mental
COOL-LAMPS III: Discovery of a 25".9 Separation Quasar Lensed by a Merging Galaxy Cluster
In the third paper from the COOL-LAMPS Collaboration, we report the discovery
of COOL J0542-2125, a gravitationally lensed quasar at , observed as
three images due to an intervening massive galaxy cluster at . The
lensed quasar images were identified in a search for lens systems in recent
public optical imaging data and have separations on the sky up to 25".9, wider
than any previously known lensed quasar. The galaxy cluster acting as a strong
lens appears to be in the process of merging, with two sub-clusters separated
by Mpc in the plane of the sky, and their central galaxies showing a
radial velocity difference of km/s. Both cluster cores show
strongly lensed images of an assortment of background sources, as does the
region between them. A preliminary strong lens model implies masses of $M(<250\
\rm{kpc}) = 1.79^{+0.16} _{-0.01} \times 10^{14} M_{\odot}M(<250\
\rm{kpc}) = 1.48^{+0.04}_{-0.10} \times 10^{14} M_{\odot}$ for the East and
West sub-clusters, respectively. This line of sight is also coincident with a
ROSAT ALL-sky Survey source, centered between the two confirmed cluster halos
reminiscent of other major cluster-scale mergers.Comment: 13 pages, 6 figures. Submitted to Ap
The Cosmic Telescope that Lenses the Sunburst Arc, PSZ1 G311.65-18.48: Strong Gravitational Lensing model and Source Plane Analysis
We present a strong lensing analysis of the cluster PSZ1 G311.65-18.48, based
on Hubble Space Telescope imaging, archival VLT/MUSE spectroscopy, and Chandra
X-ray data. This cool-core cluster (z=0.443) lenses the brightest lensed galaxy
known, dubbed the "Sunburst Arc" (z=2.3703), a Lyman continuum (LyC) emitting
galaxy multiply-imaged 12 times. We identify in this field 14 additional
strongly-lensed galaxies to constrain a strong lens model, and report secure
spectroscopic redshifts of four. We measure a projected cluster core mass of
M(<250 kpc)=2.93+0.01/-0.02x10^14M_sun. The two least-magnified but complete
images of the Sunburst Arc's source galaxy are magnified by ~13x, while the LyC
clump is magnified by ~4-80x. We present time delay predictions and conclusive
evidence that a discrepant clump in the Sunburst Arc, previously claimed to be
a transient, is not variable, thus strengthening the hypothesis that it results
from an exceptionally high magnification. A source plane reconstruction and
analysis of the Sunburst Arc finds its physical size to be 1x2 kpc, and that it
is resolved in three distinct directions in the source plane, 0, 40, and 75
degrees (east of North). We place an upper limit of r <~ 50 pc on the source
plane size of unresolved clumps, and r<~ 32 pc for the LyC clump. Finally, we
report that the Sunburst Arc is likely in a system of two or more galaxies
separated by <~6 kpc in projection. Their interaction may drive star formation
and could play a role in the mechanism responsible for the leaking LyC
radiation.Comment: 31 pages, 14 figures, 4 tables. Submitted to Ap
Gene expression differences in relation to age and social environment in queen and worker bumble bees
Eusocial insects provide special insights into the genetic pathways influencing aging because of their long-lived queens and flexible aging schedules. Using qRT-PCR in the primitively eusocial bumble bee Bombus terrestris (Linnaeus), we investigated expression levels of four candidate genes associated with taxonomically widespread age-related pathways (coenzyme Q biosynthesis protein 7, COQ7; DNA methyltransferase 3, Dnmt3; foraging, for; and vitellogenin, vg). In Experiment 1, we tested how expression changes with queen relative age and productivity. We found a significant age-related increase in COQ7 expression in queen ovary. In brain, all four genes showed higher expression with increasing female (queen plus worker) production, with this relationship strengthening as queen age increased, suggesting a link with the positive association of fecundity and longevity found in eusocial insect queens. In Experiment 2, we tested effects of relative age and social environment (worker removal) in foundress queens and effects of age and reproductive status in workers. In this experiment, workerless queens showed significantly higher for expression in brain, as predicted if downregulation of for is associated with the cessation of foraging by foundress queens following worker emergence. Workers showed a significant age-related increase in Dnmt3 expression in fat body, suggesting a novel association between aging and methylation in B. terrestris. Ovary activation was associated with significantly higher vg expression in fat body and, in younger workers, in brain, consistent with vitellogenin's ancestral role in regulating egg production. Overall, our findings reveal a mixture of novel and conserved features in age-related genetic pathways under primitive eusociality
The SPTPoL extended cluster survey
We describe the observations and resultant galaxy cluster catalog from the 2770 deg2 SPTpol Extended Cluster Survey (SPT-ECS). Clusters are identified via the Sunyaev-Zel'dovich (SZ) effect and confirmed with a combination of archival and targeted follow-up data, making particular use of data from the Dark Energy Survey (DES). With incomplete follow-up we have confirmed as clusters 244 of 266 candidates at a detection significance ξ ≥ 5 and an additional 204 systems at 4 4 threshold, and 10% of their measured SZ flux. We associate SZ-selected clusters, from both SPT-ECS and the SPT-SZ survey, with clusters from the DES redMaPPer sample, and we find an offset distribution between the SZ center and central galaxy in general agreement with previous work, though with a larger fraction of clusters with significant offsets. Adopting a fixed Planck-like cosmology, we measure the optical richness-SZ mass (l - M) relation and find it to be 28% shallower than that from a weak-lensing analysis of the DES data-a difference significant at the 4σ level-with the relations intersecting at λ = 60. The SPT-ECS cluster sample will be particularly useful for studying the evolution of massive clusters and, in combination with DES lensing observations and the SPT-SZ cluster sample, will be an important component of future cosmological analyses
Lifespan-Extending Effects of Royal Jelly and Its Related Substances on the Nematode Caenorhabditis elegans
One of the most important challenges in the study of aging is to discover compounds with longevity-promoting activities and to unravel their underlying mechanisms. Royal jelly (RJ) has been reported to possess diverse beneficial properties. Furthermore, protease-treated RJ (pRJ) has additional pharmacological activities. Exactly how RJ and pRJ exert these effects and which of their components are responsible for these effects are largely unknown. The evolutionarily conserved mechanisms that control longevity have been indicated. The purpose of the present study was to determine whether RJ and its related substances exert a lifespan-extending function in the nematode Caenorhabditis elegans and to gain insights into the active agents in RJ and their mechanism of action.We found that both RJ and pRJ extended the lifespan of C. elegans. The lifespan-extending activity of pRJ was enhanced by Octadecyl-silica column chromatography (pRJ-Fraction 5). pRJ-Fr.5 increased the animals' lifespan in part by acting through the FOXO transcription factor DAF-16, the activation of which is known to promote longevity in C. elegans by reducing insulin/IGF-1 signaling (IIS). pRJ-Fr.5 reduced the expression of ins-9, one of the insulin-like peptide genes. Moreover, pRJ-Fr.5 and reduced IIS shared some common features in terms of their effects on gene expression, such as the up-regulation of dod-3 and the down-regulation of dod-19, dao-4 and fkb-4. 10-Hydroxy-2-decenoic acid (10-HDA), which was present at high concentrations in pRJ-Fr.5, increased lifespan independently of DAF-16 activity.These results demonstrate that RJ and its related substances extend lifespan in C. elegans, suggesting that RJ may contain longevity-promoting factors. Further analysis and characterization of the lifespan-extending agents in RJ and pRJ may broaden our understanding of the gene network involved in longevity regulation in diverse species and may lead to the development of nutraceutical interventions in the aging process
Genome-wide standing variation facilitates long-term response to bidirectional selection for antibody response in chickens
Influence of the post-collision interaction on interference effects in ionization of H2by proton impact
We have performed a kinematically complete experiment on ionization of H2 by 75 keV proton impact leading to electrons with a speed equal to the projectile speed. By comparing cross sections measured with a coherent and an incoherent projectile beam we were able to perform a detailed analysis of interference effects. We found that the interference structure is significantly more damped than for a smaller electron energy studied previously. This damping is further increased if kinematic conditions are selected which favor a strong role of the post-collisional interaction between the scattered projectile and the electron ejected to the continuum by a preceding primary interaction with the projectile
Triple Differential Study of Ionization of H₂ by Proton Impact for Varying Electron Ejection Geometries
We have performed a kinematically complete experiment on ionization of H2 by 75 keV proton impact. The triple differential cross sections (TDCS) extracted from the measurement were compared to a molecular 3-body distorted wave (M3DW) calculation for three different electron ejection geometries. Overall, the agreement between experiment and theory is better than in the case of a helium target for the same projectile. Nevertheless, significant quantitative discrepancies remain, which probably result from the capture channel, which may be strongly coupled to the ionization channel. Therefore, improved agreement could be expected from a non-perturbative coupled-channel approach
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