10,867 research outputs found
Effects of CO2-induced pH reduction on the exoskeleton structure and biophotonic properties of the shrimp Lysmata californica.
The anticipated effects of CO2-induced ocean acidification on marine calcifiers are generally negative, and include dissolution of calcified elements and reduced calcification rates. Such negative effects are not typical of crustaceans for which comparatively little ocean acidification research has been conducted. Crustaceans, however, depend on their calcified exoskeleton for many critical functions. Here, we conducted a short-term study on a common caridean shrimp, Lysmata californica, to determine the effect of CO2-driven reduction in seawater pH on exoskeleton growth, structure, and mineralization and animal cryptic coloration. Shrimp exposed to ambient (7.99 ± 0.04) and reduced pH (7.53 ± 0.06) for 21 days showed no differences in exoskeleton growth (percent increase in carapace length), but the calcium weight percent of their cuticle increased significantly in reduced pH conditions, resulting in a greater Ca:Mg ratio. Cuticle thickness did not change, indicating an increase in the mineral to matrix ratio, which may have mechanical consequences for exoskeleton function. Furthermore, there was a 5-fold decrease in animal transparency, but no change in overall shrimp coloration (red). These results suggest that even short-term exposure to CO2-induced pH reduction can significantly affect exoskeleton mineralization and shrimp biophotonics, with potential impacts on crypsis, physical defense, and predator avoidance
DTB 016 Allen D. Taylor 5-13-2022
In this interview, Pastor Allen D. Taylor is interviewed by Kern Jackson in Delaware Street Baptist Church of Mobile, Alabama. They discuss some of the history of the church building and the congregation. Pastor Taylor also relates some memories of his upbringing and his family history; his mother, Idell Taylor, was raised in the Down the Bay neighborhood of Mobile. He also shares his memories of Rev. P.H. Lewis as a preacher and as an organizer. Pastor Taylor discusses some of his own philosophy of and reflections on worship and theology, and he talks about the presence and meaning of food in his home life growing up and in the church. Pastor Taylor attended Mae Eanes elementary and Williamson High School, and he shares some memories of each. He also reflects on his work experience as a pipefitter, and the educational and practical features that shaped it. And he shares some memories of when Hurricane Frederic hit Mobile
Shaped nozzles for cryogenic buffer gas beam sources
Cryogenic buffer gas beams are important sources of cold molecules. In this
work we explore the use of a converging-diverging nozzle with a buffer-gas
beam. We find that, under appropriate circumstances, the use of a nozzle can
produce a beam with improved collimation, lower transverse temperatures, and
higher fluxes per solid angle
Extreme AGN Feedback and Cool Core Destruction in the X-ray Luminous Galaxy Cluster MACS J1931.8-2634
We report on a deep, multiwavelength study of the galaxy cluster MACS
J1931.8-2634 using Chandra X-ray, Subaru optical, and VLA 1.4 GHz radio data.
This cluster (z=0.352) harbors one of the most X-ray luminous cool cores yet
discovered, with an equivalent mass cooling rate within the central 50 kpc is
approximately 700 solar masses/yr. Unique features observed in the central core
of MACSJ1931.8-2634 hint to a wealth of past activity that has greatly
disrupted the original cool core. We observe a spiral of relatively cool,
dense, X-ray emitting gas connected to the cool core, as well as highly
elongated intracluster light (ICL) surrounding the cD galaxy. Extended radio
emission is observed surrounding the central AGN, elongated in the east-west
direction, spatially coincident with X-ray cavities. The power input required
to inflate these `bubbles' is estimated from both the X-ray and radio emission
to reside between 4 and 14e45 erg/s, putting it among the most powerful jets
ever observed. This combination of a powerful AGN outburst and bulk motion of
the cool core have resulted in two X-ray bright ridges to form to the north and
south of the central AGN at a distance of approximately 25 kpc. The northern
ridge has spectral characteristics typical of cool cores and is consistent with
being a remnant of the cool core after it was disrupted by the AGN and bulk
motions. It is also the site of H-alpha filaments and young stars. The X-ray
spectroscopic cooling rate associated with this ridge is approximately 165
solar masses/yr, which agrees with the estimate of the star formation rate from
broad-band optical imaging (170 solar masses/yr). MACS J1931.8-2634 appears to
harbor one of most profoundly disrupted low entropy cores observed in a
cluster, and offers new insights into the survivability of cool cores in the
context of hierarchical structure formation.Comment: 19 pages, 15 figures, 5 tables. Accepted by MNRAS for publication
September 30 201
Mitochondrial DNA Variation among \u3ci\u3eMuscidifurax\u3c/i\u3e spp. (Hymenoptera: Pteromalidae), Pupal Parasitoids of Filth Flies (Diptera)
Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequencing analyses were used to characterize an amplicon of ~625 bp in 4 of the 5 nominate species of Muscidifurax Girault & Sanders, pupal parasitoids of muscoid flies. A single polymorphic nucleotide site was observed among 2 samples of M. raptor Girault & Sanders. No sequence variation was observed among 3 samples of M. raptorellus Kogan & Legner. The sequence of M. uniraptor Kogan & Legner was identical to that of M. raptorellus. Nucleotide divergence among the Muscidifurax spp. ranged from 0.14 to 0.18 substitutions per nucleotide. Muscidifurax zaraptor Kogan & Legner exhibited multiple haplotypes, 2 of which were characterized by sequencing and 4 others by PCR-RFLP. The sequenced haplotypes differed by 0.08 nucleotide substitutions per site. Restriction site analysis indicated that nucleotide divergence ranged from 0.03 to 0.10 among all 6 haplotypes. Analysis of progeny from individual females indicated that the observed variation in M. zaraptor was caused by multiple haplotypes within individuals rather than differentiation among individuals. These results bring to question the specific status of M. uniraptor and indicate that the genus is native to the Western Hemisphere, and not introduced with their primary host, Musca domestica L, as previously proposed. Heteroplasmy and translocation of aportion of the mitochondrial genome to the nuclear genome are discussed as possible causes for the variation observed in M. zaraptor
Radio galaxies and magnetic fields in A514
A514 contains six extended and polarized radio sources located at various
projected distances from the cluster center. Here we present a detailed study
of these six radio sources in total intensity and polarization using the Very
Large Array at 3.6 and 6 cm. Since the radio sources sample different lines of
sight across the cluster, an analysis of the Faraday Rotation Measures (RMs)
provides information on the strength and the structure of the cluster magnetic
field. These sources show a decreasing Faraday Rotation Measure with increasing
distance from the cluster center. We estimate the strength of the magnetic
field to be ~3-7 uG in the cluster center. From the RM structure across the
stronger and more extended sources we estimate the coherence length of the
magnetic field to be about 9 kpc at the cluster center.Comment: 16 pages, 18 ps figures accepted by A&
Towards an integrated proteomic and glycomic approach to finding cancer biomarkers
Advances in mass spectrometry have had a great impact on the field of proteomics. A major challenge of proteomic analysis has been the elucidation of glycan modifications of proteins in complex proteomes. Glycosylation is the most structurally elaborate and diverse type of protein post-translational modification and, because of this, proteomics and glycomics have largely developed independently. However, given that such a large proportion of proteins contain glycan modifications, and that these may be important for their function or may produce biologically relevant protein variation, a convergence of the fields of glycomics and proteomics would be highly desirable. Here we review the current status of glycoproteomic efforts, focusing on the identification of glycoproteins as cancer biomarkers
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