172 research outputs found
Use of structured expert judgment to forecast invasions by bighead and silver carp in Lake Erie
Identifying which nonindigenous species will become invasive and forecasting the damage they will cause is difficult and presents a significant problem for natural resource management. Often, the data or resources necessary for ecological risk assessment are incomplete or absent, leaving environmental decision makers ill equipped to effectively manage valuable natural resources. Structured expert judgment (SEJ) is a mathematical and performance‐based method of eliciting, weighting, and aggregating expert judgments. In contrast to other methods of eliciting and aggregating expert judgments (where, for example, equal weights may be assigned to experts), SEJ weights each expert on the basis of his or her statistical accuracy and informativeness through performance measurement on a set of calibration variables. We used SEJ to forecast impacts of nonindigenous Asian carp (Hypophthalmichthys spp.) in Lake Erie, where it is believed not to be established. Experts quantified Asian carp biomass, production, and consumption and their impact on 4 fish species if Asian carp were to become established. According to experts, in Lake Erie Asian carp have the potential to achieve biomass levels that are similar to the sum of biomasses for several fishes that are harvested commercially or recreationally. However, the impact of Asian carp on the biomass of these fishes was estimated by experts to be small, relative to long term average biomasses, with little uncertainty. Impacts of Asian carp in tributaries and on recreational activities, water quality, or other species were not addressed. SEJ can be used to quantify key uncertainties of invasion biology and also provide a decision‐support tool when the necessary information for natural resource management and policy is not available.El Uso de Juicio Experto Estructurado para Predecir Invasiones de Carpas Asiáticas en el Lago ErieResumenIdentificar cuáles especies no‐nativas se volverán invasoras y predecir el daño que causarán es complicado y presenta un problema significativo para el manejo de recursos naturales. Con frecuencia los datos o recursos necesarios para la evaluación de riesgo ecológico están incompletos o son inexistentes, lo que deja mal equipados a quienes toman las decisiones ambientales para manejar efectivamente recursos naturales valiosos. El juicio experto estructurado (JEE) es un método con bases matemáticas y de desempeño para obtener, sopesar y agregar juicios expertos. En contraste con otros métodos de obtención y agregación de juicios expertos (donde, por ejemplo, se le pueden asignar pesos iguales a los expertos), JEE sopesa a cada experto con base en su asertividad estadística y capacidad de informar por medio de la medida de desempeño en un conjunto de variables de calibración. Usamos JEE para predecir los impactos de las carpas asiáticas no‐nativas Hypophthalmichthys spp. en el Lago Erie, donde se cree que no se ha establecido. Los expertos cuantificaron la biomasa, producción y consumo de la carpa asiática y su impacto sobre cuatro especies de peces si la carpa asiática se llegara a establecer en el lago. De acuerdo a los expertos, en el Lago Erie, la carpa asiática tiene el potencial de adquirir niveles de biomasa similares a la suma de biomasa de varios peces que se han cultivado comercialmente o recreativamente. Sin embargo, se estimó por los expertos que el impacto de la carpa asiática sobre la biomasa de estos peces sería pequeño, con poca incertidumbre. Los impactos de la carpa asiática sobre los tributarios y las actividades recreativas, la calidad del agua o sobre otras especies no se evaluaron. El JEE puede usarse para cuantificar incertidumbres clave de la biología de la invasión y también proporcionar una herramienta de apoyo para las decisiones cuando la información necesaria para el manejo de los recursos naturales y la política no está disponible.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110571/1/cobi12369.pd
Comparative studies on faecal egg counting techniques used for the detection of gastrointestinal parasites of equines: A systematic review
Faecal egg counting techniques (FECT) form the cornerstone for the detection of gastrointestinal parasites in equines. For this purpose, several flotation, centrifugation, image- and artificial intelligence-based techniques are used, with varying levels of performance. This review aimed to critically appraise the literature on the assessment and comparison of various coprological techniques and/or modifications of these techniques used for equines and to identify the knowledge gaps and future research directions. We searched three databases for published scientific studies on the assessment and comparison of FECT in equines and included 27 studies in the final synthesis. Overall, the performance parameters of McMaster (81.5%), Mini-FLOTAC® (33.3%) and simple flotation (25.5%) techniques were assessed in most of the studies, with 77.8% of them comparing the performance of at least two or three methods. The detection of strongyle, Parascaris spp. and cestode eggs was assessed for various FECT in 70.4%, 18.5% and 18.5% studies, respectively. A sugar-based flotation solution with a specific gravity of ≥1.2 was found to be the optimal flotation solution for parasitic eggs in the majority of FECT. No uniform or standardised protocol was followed for the comparison of various FECT, and the tested sample size (i.e. equine population and faecal samples) also varied substantially across all studies. To the best of our knowledge, this is the first systematic review to evaluate studies on the comparison of FECT in equines and it highlights important knowledge gaps in the evaluation and comparison of such techniques
Molecular detection of Strongyloides sp. in Australian thoroughbred foals
Background
Strongyloides westeri is found in the small intestine of young horses, mainly in foals up to about 16 weeks of age. The main source of infection for foals is through transmammary transmission, and foals can develop acute diarrhoea, weakness, dermatitis and respiratory signs. The epidemiology of S. westeri in Australia is largely unknown. Further, molecular techniques have never been employed for detection of S. westeri in horses. This pilot study aimed to assess the utility of a molecular phylogenetic method for the detection of S. westeri in the faeces of foals.
Methods
Faecal samples were collected from a foal of less than 2 months of age, and eggs of Strongyloides sp. were detected using the modified McMaster technique. DNA was extracted from purified eggs, and a partial fragment of the small subunit of the nuclear ribosomal DNA (18S) was characterised using polymerase chain reaction, DNA sequencing and phylogenetic methods.
Results
Microscopic examination of faeces revealed small ellipsoidal eggs typical of Strongyloides sp. The 18S sequence generated by PCR in this study revealed 98.4% identity with that of a reference sequence of S. westeri available from GenBank. Phylogenetic analyses revealed a polyphyletic clustering of S. westeri sequences.
Conclusion
This is the first study reporting the detection of DNA of Strongyloides sp. in faeces of a foal using a molecular phylogenetic approach targeting the variable region of 18S rDNA. It is anticipated that this study will allow future molecular epidemiological studies on S. westeri in horses
A mechanism for the inhibition of DNA-PK-mediated DNA sensing by a virus
The innate immune system is critical in the response to infection by pathogens and it is activated by pattern recognition receptors (PRRs) binding to pathogen associated molecular patterns (PAMPs). During viral infection, the direct recognition of the viral nucleic acids, such as the genomes of DNA viruses, is very important for activation of innate immunity. Recently, DNA-dependent protein kinase (DNA-PK), a heterotrimeric complex consisting of the Ku70/Ku80 heterodimer and the catalytic subunit DNA-PKcs was identified as a cytoplasmic PRR for DNA that is important for the innate immune response to intracellular DNA and DNA virus infection. Here we show that vaccinia virus (VACV) has evolved to inhibit this function of DNA-PK by expression of a highly conserved protein called C16, which was known to contribute to virulence but by an unknown mechanism. Data presented show that C16 binds directly to the Ku heterodimer and thereby inhibits the innate immune response to DNA in fibroblasts, characterised by the decreased production of cytokines and chemokines. Mechanistically, C16 acts by blocking DNA-PK binding to DNA, which correlates with reduced DNA-PK-dependent DNA sensing. The C-terminal region of C16 is sufficient for binding Ku and this activity is conserved in the variola virus (VARV) orthologue of C16. In contrast, deletion of 5 amino acids in this domain is enough to knockout this function from the attenuated vaccine strain modified vaccinia virus Ankara (MVA). In vivo a VACV mutant lacking C16 induced higher levels of cytokines and chemokines early after infection compared to control viruses, confirming the role of this virulence factor in attenuating the innate immune response. Overall this study describes the inhibition of DNA-PK-dependent DNA sensing by a poxvirus protein, adding to the evidence that DNA-PK is a critical component of innate immunity to DNA viruses
Curved Tails in Polymerization-Based Bacterial Motility
The curved actin ``comet-tail'' of the bacterium Listeria monocytogenes is a
visually striking signature of actin polymerization-based motility. Similar
actin tails are associated with Shigella flexneri, spotted-fever Rickettsiae,
the Vaccinia virus, and vesicles and microspheres in related in vitro systems.
We show that the torque required to produce the curvature in the tail can arise
from randomly placed actin filaments pushing the bacterium or particle. We find
that the curvature magnitude determines the number of actively pushing
filaments, independent of viscosity and of the molecular details of force
generation. The variation of the curvature with time can be used to infer the
dynamics of actin filaments at the bacterial surface.Comment: 8 pages, 2 figures, Latex2
Modeling and characterization of TES-based detectors for the Ricochet experiment
Coherent elastic neutrino-nucleus scattering (CENS) offers a valuable
approach in searching for physics beyond the Standard Model. The Ricochet
experiment aims to perform a precision measurement of the CENS spectrum at
the Institut Laue-Langevin nuclear reactor with cryogenic solid-state
detectors. The experiment plans to employ an array of cryogenic thermal
detectors, each with a mass around 30 g and an energy threshold of sub-100 eV.
The array includes nine detectors read out by Transition-Edge Sensors (TES).
These TES based detectors will also serve as demonstrators for future neutrino
experiments with thousands of detectors. In this article we present an update
in the characterization and modeling of a prototype TES detector.Comment: Submitted to LTD20 proceedin
First demonstration of 30 eVee ionization energy resolution with Ricochet germanium cryogenic bolometers
The future Ricochet experiment aims to search for new physics in the
electroweak sector by measuring the Coherent Elastic Neutrino-Nucleus
Scattering process from reactor antineutrinos with high precision down to the
sub-100 eV nuclear recoil energy range. While the Ricochet collaboration is
currently building the experimental setup at the reactor site, it is also
finalizing the cryogenic detector arrays that will be integrated into the
cryostat at the Institut Laue Langevin in early 2024. In this paper, we report
on recent progress from the Ge cryogenic detector technology, called the
CryoCube. More specifically, we present the first demonstration of a 30~eVee
(electron equivalent) baseline ionization resolution (RMS) achieved with an
early design of the detector assembly and its dedicated High Electron Mobility
Transistor (HEMT) based front-end electronics. This represents an order of
magnitude improvement over the best ionization resolutions obtained on similar
heat-and-ionization germanium cryogenic detectors from the EDELWEISS and
SuperCDMS dark matter experiments, and a factor of three improvement compared
to the first fully-cryogenic HEMT-based preamplifier coupled to a CDMS-II
germanium detector. Additionally, we discuss the implications of these results
in the context of the future Ricochet experiment and its expected background
mitigation performance.Comment: 10 pages, 5 figures, 1 tabl
The role of heterodimerization between VEGFR-1 and VEGFR-2 in the regulation of endothelial cell homeostasis
VEGF-A activity is tightly regulated by ligand and receptor availability. Here we investigate the physiological function of heterodimers between VEGF receptor-1 (VEGFR-1; Flt-1) and VEGFR-2 (KDR; Flk-1) (VEGFR(1-2)) in endothelial cells with a synthetic ligand that binds specifically to VEGFR(1-2). The dimeric ligand comprises one VEGFR-2-specific monomer (VEGF-E) and a VEGFR-1-specific monomer (PlGF-1). Here we show that VEGFR(1-2) activation mediates VEGFR phosphorylation, endothelial cell migration, sustained in vitro tube formation and vasorelaxation via the nitric oxide pathway. VEGFR(1-2) activation does not mediate proliferation or elicit endothelial tissue factor production, confirming that these functions are controlled by VEGFR-2 homodimers. We further demonstrate that activation of VEGFR(1-2) inhibits VEGF-A-induced prostacyclin release, phosphorylation of ERK1/2 MAP kinase and mobilization of intracellular calcium from primary endothelial cells. These findings indicate that VEGFR-1 subunits modulate VEGF activity predominantly by forming heterodimer receptors with VEGFR-2 subunits and such heterodimers regulate endothelial cell homeostasis
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