290 research outputs found
The Evaluation of the Response of American Eels to Rapid Decompression
Hydropower dams are used throughout the world to generate electricity and dams can negatively affect fish, as they can hinder or block migration or be a source of injury and mortality during passage. When moving downstream, fish can pass through the turbines instead of other routes (e.g. spillway and juvenile bypass system)where there is a sudden decrease in pressure that can cause barotraumas, injuries from the changes in barometric pressure, (e.g., hemorrhaging, embolism, ruptured organs) due to internal gases expanding. To determine the response of American eels, Anguilla rostrate, to rapid decompression, testing was conducted in the Mobile Aquatic Barotrauma Laboratory (MABL) at PNNL’s Aquatic Research Lab between 6 June and 5 August 2016. In total, 105 eels were tested in MABL’s hyper/hypobaric chambers by simulating the rapid decompression experienced in turbines. Eels were acclimated to 25 feet depth and the nadir, lowest pressure the eels experienced, during the test was measured. This was done to determine the ratio of pressure change (RPC) the eels experienced during testing (i.e., acclimation pressure/nadir pressure). After exposure, the eels were held for two days to monitor survival before a necropsy was performed. There were only two mortalities observed (1.9%) in the study. Twenty-one fish were found to have non-fatal barotraumas. However, these injuries are fatal for other species (e.g., Chinook salmon). The maximum RPC for fish with injuries was 11.32, while the greatest RPC in the study was 19.66, and so further research is needed to determine if there is a RPC that will result in 100% mortality for this species. The results provide information that can be used in the design and operation of turbines to minimize mortality for fish that pass through
A New Generation Microarray for the Simultaneous Detection and Identification of Yersinia pestis and Bacillus anthracis in Food
The use of microarrays as a multiple analytic system has generated increased interest and provided a powerful analytical tool for the simultaneous detection of pathogens in a single experiment. A wide array of applications for this technology has been reported. A low density oligonucleotide microarray was generated from the genetic sequences of Y. pestis and B. anthracis and used to fabricate a microarray chip. The new generation chip, consisting of 2,240 spots in 4 quadrants with the capability of stripping/rehybridization, was designated as "Y-PESTIS/B-ANTHRACIS 4x2K Array." The chip was tested for specificity using DNA from a panel of bacteria that may be potentially present in food. In all, 37 unique Y. pestis-specific and 83 B. anthracis-specific probes were identified. The microarray assay distinguished Y. pestis and B. anthracis from the other bacterial species tested and correctly identified the Y. pestis-specific oligonucleotide probes using DNA extracted from experimentally inoculated milk samples. Using a whole genome amplification method, the assay was able to detect as low as 1 ng genomic DNA as the start sample. The results suggest that oligonucleotide microarray can specifically detect and identify Y. pestis and B. anthracis and may be a potentially useful diagnostic tool for detecting and confirming the organisms in food during a bioterrorism event
Plant organelle targeting cell penetrating peptides
xii, 131 leaves : illustrations (chiefly coloured) ; 29 cmTo address the limitations of conventional nuclear transformation I have developed a peptide based gene delivery system to genetically manipulate the genomes of plant cell mitochondria and plastids. Plant organelle targeting cell penetrating peptides (POTCPPs) are peptides that form nanoparticles composed of short peptides and double-stranded DNA (dsDNA). The peptides have cell penetrating properties and specific organelle targeting properties. These properties enabled the peptides to translocate their cargo across the cell wall and outer plasma membrane of tissue cultured plant cells to deliver dsDNA to the mitochondria or the chloroplast and have it expressed in organello. The POTCPP transfection method represents the first report of a successful in vivo plant cell mitochondrial transfection and a peptide based plastid transfection within a monocot species. The POTCPP transfection method can be applied to organelle gene targeting, functional genomic and to the study of transient gene expression in tissue cultured plant cells
Country Concepts and the Rational Actor Trap: Limitations to Strategic Management of International NGOs
Growing criticism of inefficient development aid demanded new planning instruments of donors, including international NGOs (INGOs). A reorientation from isolated project-planning towards holistic country concepts and the increasing rationality of a result-orientated planning process were seen as answer. However, whether these country concepts - newly introduced by major INGOs too - have increased the efficiency of development cooperation is open to question. Firstly, there have been counteracting external factors, like the globalization of the aid business, that demanded structural changes in the composition of INGO portfolios towards growing short-term humanitarian aid; this was hardly compatible with the requirements of medium-term country planning. Secondly, the underlying vision of rationality as a remedy for the major ills of development aid was in itself a fallacy. A major change in the methodology of planning, closely connected with a shift of emphasis in the approach to development cooperation, away from project planning and service delivery, towards supporting the socio-cultural and political environment of the recipient communities, demands a reorientation of aid management: The most urgent change needed is by donors, away from the blinkers of result-orientated planning towards participative organizational cultures of learning.Des critiques croissantes de l'aide au développement inefficace exigent de nouveaux instruments de planification des bailleurs de fonds, y compris les ONG internationales (ONGI). Une réorientation de la planification des projets isolés vers des concepts holistiques de la planification de l’aide par pays ainsi que la rationalité croissante d'un processus de planification orientée vers les résultats ont été considérés comme réponse. Toutefois, si ces concepts de pays - nouvellement introduites par les grandes OING eux aussi - ont augmenté l'efficacité de la coopération au développement est ouvert à la question. Tout d'abord, il y a eu l’impact des facteurs externes, comme la mondialisation de l'entreprise de l'aide, qui a exigé des changements structurels dans la composition des portefeuilles des OING vers la croissance de l'aide humanitaire à court terme. Cela était difficilement compatible avec les exigences de l'aménagement du territoire à moyen terme. Deuxièmement, la vision sous-jacente de la rationalité accrue de la planification, concentré sur les resultats, comme un remède pour les grands maux de l'aide au développement était en soi une erreur. Un changement majeur dans la méthodologie de la planification, étroitement liée à un changement d'orientation dans l'approche de la coopération au développement, qui n’est pas concentrer sur planification du projet et la prestation de services, mais qui soutienne l'environnement socio-culturel et politique des communautés bénéficiaires, exige une réorientation de la gestion de l’aide: Le changement le plus urgent est un changement par les donateurs eux-mêmes, qui devrait implanter des cultures de collaboration étroit avec les partenaires et la population locale
The population of merging compact binaries inferred using gravitational waves through GWTC-3
We report on the population properties of 76 compact binary mergers detected with gravitational waves below a false alarm rate of 1 per year through GWTC-3. The catalog contains three classes of binary mergers: BBH, BNS, and NSBH mergers. We infer the BNS merger rate to be between 10 and 1700 and the NSBH merger rate to be between 7.8 and 140 , assuming a constant rate density versus comoving volume and taking the union of 90% credible intervals for methods used in this work. Accounting for the BBH merger rate to evolve with redshift, we find the BBH merger rate to be between 17.9 and 44 at a fiducial redshift (z=0.2). We obtain a broad neutron star mass distribution extending from to . We can confidently identify a rapid decrease in merger rate versus component mass between neutron star-like masses and black-hole-like masses, but there is no evidence that the merger rate increases again before 10 . We also find the BBH mass distribution has localized over- and under-densities relative to a power law distribution. While we continue to find the mass distribution of a binary's more massive component strongly decreases as a function of primary mass, we observe no evidence of a strongly suppressed merger rate above . The rate of BBH mergers is observed to increase with redshift at a rate proportional to with for . Observed black hole spins are small, with half of spin magnitudes below . We observe evidence of negative aligned spins in the population, and an increase in spin magnitude for systems with more unequal mass ratio
Constraints on the cosmic expansion history from GWTC-3
We use 47 gravitational-wave sources from the Third LIGO-Virgo-KAGRA Gravitational-Wave Transient Catalog (GWTC-3) to estimate the Hubble parameter , including its current value, the Hubble constant . Each gravitational-wave (GW) signal provides the luminosity distance to the source and we estimate the corresponding redshift using two methods: the redshifted masses and a galaxy catalog. Using the binary black hole (BBH) redshifted masses, we simultaneously infer the source mass distribution and . The source mass distribution displays a peak around , followed by a drop-off. Assuming this mass scale does not evolve with redshift results in a measurement, yielding ( credible interval) when combined with the measurement from GW170817 and its electromagnetic counterpart. This represents an improvement of 17% with respect to the estimate from GWTC-1. The second method associates each GW event with its probable host galaxy in the catalog GLADE+, statistically marginalizing over the redshifts of each event's potential hosts. Assuming a fixed BBH population, we estimate a value of with the galaxy catalog method, an improvement of 42% with respect to our GWTC-1 result and 20% with respect to recent studies using GWTC-2 events. However, we show that this result is strongly impacted by assumptions about the BBH source mass distribution; the only event which is not strongly impacted by such assumptions (and is thus informative about ) is the well-localized event GW190814
Search for continuous gravitational wave emission from the Milky Way center in O3 LIGO--Virgo data
We present a directed search for continuous gravitational wave (CW) signals
emitted by spinning neutron stars located in the inner parsecs of the Galactic
Center (GC). Compelling evidence for the presence of a numerous population of
neutron stars has been reported in the literature, turning this region into a
very interesting place to look for CWs. In this search, data from the full O3
LIGO--Virgo run in the detector frequency band have been
used. No significant detection was found and 95 confidence level upper
limits on the signal strain amplitude were computed, over the full search band,
with the deepest limit of about at .
These results are significantly more constraining than those reported in
previous searches. We use these limits to put constraints on the fiducial
neutron star ellipticity and r-mode amplitude. These limits can be also
translated into constraints in the black hole mass -- boson mass plane for a
hypothetical population of boson clouds around spinning black holes located in
the GC.Comment: 25 pages, 5 figure
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