8,400 research outputs found
Comparative Microbial Dynamics in Crassostrea virginica and Crassostrea ariakensis
Considerations to introduce the Suminoe or Asian oyster Crassostrea ariakensis along the East Coast have raised many questions regarding ecology, economics, and human health. To date, research has focused primarily on the ecological and socioeconomic implications of this initiative, yet few studies have assessed its potential
impact on public health. Our work compares the rates of bioaccumulation, depuration and post harvest decay of indicator organisms (such as E. coli) and Vibrio sp. between
Crassostrea virginica and Crassostrea ariakensis in the laboratory. Preliminary results suggest that the rates of bioaccumulation of E. coli in Crassostrea ariakensis were
significantly lower than those for Crassostrea virginica, depuration of E. coli was variable between the two species, and Crassostrea ariakensis post harvest decay rates of
Vibrio sp. were significantly lower than Crassostrea virginica. This research provides coastal managers with insight into the response of Crassostrea ariakensis to bacteria, an important consideration for determining appropriate management strategies for this species. Further field-based studies will be necessary to elucidate the mechanisms responsible for the differences in rates of bioaccumulation and depuration. (PDF contains 40 pages
Vibrio bacteria in raw oysters: managing risks to human health
The human-pathogenic marine bacteria Vibrio vulnificus and V. parahaemolyticus are strongly correlated with water temperature, with concentrations increasing as waters warm seasonally. Both of these bacteria can be concentrated in filter-feeding shellfish, especially oysters. Because oysters are often consumed raw, this exposes people to large doses of potentially harmful bacteria. Various models are used to predict the abundance of these bacteria in oysters, which guide shellfish harvest policy meant to reduce human health risk. Vibrio abundance and behaviour varies from site to site, suggesting that location-specific studies are needed to establish targeted risk reduction strategies. Moreover, virulence potential, rather than simple abundance, should be also be included in future modeling efforts
Primordia initiation of mushroom (Agaricus bisporus) strains on axenic casing materials
The mushroom (Agaricus bisporus) has a
requirement for a ‘‘casing layer’’ that has specific
physical, chemical and microbiological properties
which stimulate and promote the initiation of primordia.
Some of these primordia then may develop
further into sporophores, involving differentiation of
tissue. Wild and commercial strains of A. bisporus
were cultured in axenic and nonaxenic microcosms,
using a rye grain substrate covered by a range of organic
and inorganic casing materials. In axenic culture,
A. bisporus (commercial strain A15) was capable
of producing primordia and mature sporophores on
charcoal (wood and activated), anthracite coal, lignite
and zeolite, but not on bark, coir, peat, rockwool,
silica or vermiculite. Of six strains tested, only
the developmental variant mutant, B430, produced
rudimentary primordia on axenic peat-based casing
material. However, none of these rudimentary primordia
developed differentiated tissues or beyond 4
mm diameter, either on axenic casing material in the
microcosms or in larger-scale culture. In larger-scale,
nonaxenic culture, strain B430 produced severely
malformed but mature sporophores in similar numbers
to those of other strains. Typically, 3–6% of primordia
developed into mature sporophores, but significant
differences in this proportion, as well as in
the numbers of primordia produced, were recorded
between 12 A. bisporus strains
Computing labs and Technology Classroom (ClTC) Initiative: A Model for Distributed Support
DePauw University is a small, liberal arts institution with 2200 undergraduate residential students and 222 faculty members, located in Greencastle, Indiana The challenges of supporting a campus with multiple and diverse facilities are further amplified by limited staff support resources. One of the strategies for addressing these challenges led to the formation of the Computing Labs and Technology Classrooms (CLTC) initiative. The CLTC recognizes and draws on the strengths of support specialists with a wide variety of professional training and experience, who regularly collaborate in the support and management of campus-wide labs and technology classrooms
Dear Ireland When You\u27re Free
https://digitalcommons.library.umaine.edu/mmb-vp/4587/thumbnail.jp
Probing the Dark Dimension with Auger data
[Abridged] By combining swampland conjectures with observational data, it was
recently noted that our universe could stretch off in an asymptotic region of
the string landscape of vacua. In this framework, the cosmological hierarchy
problem can be resolved by the addition of one mesoscopic (dark) dimension of
size . The Planck scale of
the higher dimensional theory, , is tantalizingly close to the energy
above which the TA and Auger collaborations found conclusive evidence for a
sharp cutoff of the flux of UHECRs. It was recently suggested that since
physics becomes strongly coupled to gravity beyond , universal
features deep-rooted in the dark dimension could control the energy cutoff of
the source spectra. Conversely, in the absence of phenomena inborn within the
dark dimension, we would expect a high variance of the cosmic ray maximum
energy characterizing the source spectra, reflecting the many different
properties inherent to the most commonly assumed UHECR accelerators. A recent
analysis of Auger and TA data exposed strong evidence for a correlation between
UHECRs and nearby starburst galaxies, with a global significance post-trial of
. Since these galaxies are in our cosmic backyard, the flux
attenuation factor due to cosmic ray interactions en route to Earth turns out
to be negligible. This implies that for each source, the shape of the observed
spectrum should roughly match the emission spectrum, providing a unique testing
ground for the dark dimension hypothesis. Using Auger data, we carry out a
maximum likelihood analysis to characterize the shape of the UHECR emission
from the galaxies dominating the anisotropy signal. We show that the observed
spectra could be universal only if .Comment: 17 pages, 3 figure
Narrow Line Cooling and Momentum-Space Crystals
Narrow line laser cooling is advancing the frontier for experiments ranging
from studies of fundamental atomic physics to high precision optical frequency
standards. In this paper, we present an extensive description of the systems
and techniques necessary to realize 689 nm 1S0 - 3P1 narrow line cooling of
atomic 88Sr. Narrow line cooling and trapping dynamics are also studied in
detail. By controlling the relative size of the power broadened transition
linewidth and the single-photon recoil frequency shift, we show that it is
possible to continuously bridge the gap between semiclassical and quantum
mechanical cooling. Novel semiclassical cooling process, some of which are
intimately linked to gravity, are also explored. Moreover, for laser
frequencies tuned above the atomic resonance, we demonstrate momentum-space
crystals containing up to 26 well defined lattice points. Gravitationally
assisted cooling is also achieved with blue-detuned light. Theoretically, we
find the blue detuned dynamics are universal to Doppler limited systems. This
paper offers the most comprehensive study of narrow line laser cooling to date.Comment: 14 pages, 19 figure
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