3,111 research outputs found

    Implications of Variability Patterns observed in TeV Blazars on the Structure of the Inner Jet

    Get PDF
    The recent long look X-ray observations of TeV blazars have revealed many important new features concerning their time variability. In this paper, we suggest a physical interpretation for those features based on the framework of the internal and external shock scenarios. We present a simplified model applicable to TeV blazars, and investigate through simulations how each of the model parameters would affect to the observed light curve or spectrum. In particular, we show that the internal shock scenario naturally leads to all the observed variability properties including the structure function, but for it to be applicable, the fractional fluctuation of the initial bulk Lorentz factors must be small, with sigma_gamma / gamma_average < 0.01. This implies very low dynamical efficiency of the internal shock scenario. We also suggest that several observational quantities -- such as the characteristic time scale, the relative amplitude of flares as compared to the steady (``offset'') component, and the slope of the structure function -- can be used to probe the inner jet. The results are applied to the TeV blazar Mrk421, and this, within the context of the model, leads to the determination of several physical parameters: the ejection of a shell with average thickness of ~1E13 cm occurs on average every 10 minutes, and the shells collide ~1E17 cm away from the central source.Comment: 12 pages, 13 figures, to appear in Ap

    Effect of a dry acidulant coating on the palatability of dry extruded dog food

    Get PDF
    Citation: Jeffrey, A. M., Aldrich, G. C., Huss, A. R., Knueven, C. J., & Jones, C. K. (2016). Effect of a dry acidulant coating on the palatability of dry extruded dog food. Journal of Animal Science, 94, 114-114. doi:10.2527/msasas2016-242In the pet food industry, Salmonella is getting greater scrutiny because it is considered a “reasonably foreseeable hazard” with the implementation of the Food Safety Modernization Act. Specifically, there is zero tolerance for any serotype of Salmonella in pet foods. Salmonella contamination was responsible for 78% of the Class I recalls in pet food according to the most recent Reportable Food Registry Report (FDA, 2015). One potential method of Salmonella mitigation shown to be effective was through coating the exterior of the kibble with a powdered dry acidulant, such as sodium bisulfate (SBS; Jones-Hamilton, Co.). Sodium bisulfate coating on both dog and cat kibbles was shown to provide complete mitigation of Salmonella within 14-d storage (Jeffrey et al., 2014). However, it is thought that the use of dry acidulant with a palatant for coating kibble may negatively impact palatability of a dry dog food. Therefore, the objective of this experiment was to determine if the use of a dry acidulant, SBS, would influence the palatability of a dry dog food. A single dry extruded all life stages dog food was collected from a commercial pet food manufacturer before the coating step. The kibble was coated with either 2.2% spray dried chicken liver + 0.2% SBS or 2.2% spray dried chicken liver + 0.2% powdered silica (control). A total of 20 beagles were used in a standard 2-bowl forced choice palatability test method for 2 d. Dogs were fed 400 g of both diets once per day, with bowls rotated daily to address side bias. Results were analyzed using the GLIMMIX procedure of SAS (Cary, NC). The inclusion of SBS did not affect daily preference of diet (P = 0.23). Furthermore, there was no effect of day (P = 0.18) or the interaction of treatment × day (P = 0.98). These results demonstrate that palatability is not affected by the inclusion of SBS with a palatant in the coating of dog food kibble. Considering that the inclusion of SBS has been shown to be effective at mitigating Salmonella in pet food and no negative effects on palatability were observed, the use of a dry acidulant in a dog food coating gives the industry a promising method to control Salmonella contamination of finished dog foods

    The Crustal Rigidity of a Neutron Star, and Implications for PSR 1828-11 and other Precession Candidates

    Get PDF
    We calculate the crustal rigidity parameter, b, of a neutron star (NS), and show that b is a factor 40 smaller than the standard estimate due to Baym & Pines (1971). For a NS with a relaxed crust, the NS's free-precession frequency is directly proportional to b. We apply our result for b to PSR 1828-11, a 2.5 Hz pulsar that appears to be precessing with period 511 d. Assuming this 511-d period is set by crustal rigidity, we show that this NS's crust is not relaxed, and that its reference spin (roughly, the spin for which the crust is most relaxed) is 40 Hz, and that the average spindown strain in the crust is 5 \times 10^{-5}. We also briefly describe the implications of our b calculation for other well-known precession candidates.Comment: 44 pages, 10 figures, submitted to Ap

    A Comparison of Producer Gas, Biochar, and Activated Carbon from Two Distributed Scale Thermochemical Conversion Systems used to Process Forest Biomass

    Get PDF
    Thermochemical biomass conversion systems have the potential to produce heat, power, fuels and other products from forest biomass at distributed scales that meet the needs of some forest industry facilities. However, many of these systems have not been deployed in this sector and the products they produce from forest biomass have not been adequately described or characterized with regards to chemical properties, possible uses, and markets. This paper characterizes the producer gas, biochar, and activated carbon of a 700 kg h−1 prototype gasification system and a 225 kg h−1 pyrolysis system used to process coniferous sawmill and forest residues. Producer gas from sawmill residues processed with the gasifier had higher energy content than gas from forest residues, with averages of 2.4 MJ m−3 and 9.8 MJ m−3, respectively. Gases from the pyrolysis system averaged 1.3 MJ m−3 for mill residues and 2.5 MJ m−3 for forest residues. Biochars produced have similar particle size distributions and bulk density, but vary in pH and carbon content. Biochars from both systems were successfully activated using steam activation, with resulting BET surface area in the range of commercial activated carbon. Results are discussed in the context of co-locating these systems with forest industry operations

    Greater Strength Drives Difference in Power between Sexes in the Conventional Deadlift Exercise

    Get PDF
    Limited research exists comparing sex differences in muscular power. The primary purpose of this research was to determine if differences exist in power and velocity in the conventional deadlift (CDL). A secondary purpose was to examine the relationship among power, velocity, strength, and fat free mass (FFM). Eighteen strength trained athletes with ≄1 year CDL experience (women: n = 9, 29 ± 2 years, 162.3 ± 1.8 cm, 62 ± 2.4 kg, 23.3 ± 3.2 % body fat (%BF); men: n = 9, 29 ± 3 years, 175.6 ± 1.8 cm, 85.5 ± 1.4 kg, 14.8 ± 2.4 %BF), and ≄1.5 one repetition maximum (1-RM) CDL: body mass (BM) ratio (women: 1.6 ± 0.1 1-RM CDL: BM; men: 2.3 ± 0.1 1-RM CDL: BM), performed baseline (body composition, 1-RM CDL) and experimental sessions, in which velocity and power were measured at 30%, 60%, and 90% 1-RM. Repeated measures ANOVA and bivariate correlations were conducted. Men produced higher absolute average and peak power across all loads, but higher average velocity at only 30% 1-RM. When normalized to FFM, men produced higher peak and average power; however, women produced higher peak and average velocities across all loads. FFM and 1-RM were correlated with power. Greater power observed in men is driven by larger muscle mass, which contributes to greater strength

    Genome sequences of six Phytophthora species threatening forest ecosystems

    Get PDF
    AbstractThe Phytophthora genus comprises of some of the most destructive plant pathogens and attack a wide range of hosts including economically valuable tree species, both angiosperm and gymnosperm. Many known species of Phytophthora are invasive and have been introduced through nursery and agricultural trade. As part of a larger project aimed at utilizing genomic data for forest disease diagnostics, pathogen detection and monitoring (The TAIGA project: Tree Aggressors Identification using Genomic Approaches; http://taigaforesthealth.com/), we sequenced the genomes of six important Phytophthora species that are important invasive pathogens of trees and a serious threat to the international trade of forest products. This genomic data was used to develop highly sensitive and specific detection assays and for genome comparisons and to make evolutionary inferences and will be useful to the broader plant and tree health community. These WGS data have been deposited in the International Nucleotide Sequence Database Collaboration (DDBJ/ENA/GenBank) under the accession numbers AUPN01000000, AUVH01000000, AUWJ02000000, AUUF02000000, AWVV02000000 and AWVW02000000

    Exploring the measurement of markedness and its relationship with other linguistic variables

    Get PDF
    Antonym pair members can be differentiated by each word's markedness-that distinction attributable to the presence or absence of features at morphological or semantic levels. Morphologically marked words incorporate their unmarked counterpart with additional morphs (e.g., "unlucky" vs. "lucky"); properties used to determine semantically marked words (e.g., "short" vs. "long") are less clearly defined. Despite extensive theoretical scrutiny, the lexical properties of markedness have received scant empirical study. The current paper employs an antonym sequencing approach to measure markedness: establishing markedness probabilities for individual words and evaluating their relationship with other lexical properties (e.g., length, frequency, valence). Regression analyses reveal that markedness probability is, as predicted, related to affixation and also strongly related to valence. Our results support the suggestion that antonym sequence is reflected in discourse, and further analysis demonstrates that markedness probabilities, derived from the antonym sequencing task, reflect the ordering of antonyms within natural language. In line with the Pollyanna Hypothesis, we argue that markedness is closely related to valence; language users demonstrate a tendency to present words evaluated positively ahead of those evaluated negatively if given the choice. Future research should consider the relationship of markedness and valence, and the influence of contextual information in determining which member of an antonym pair is marked or unmarked within discourse
    • 

    corecore