656 research outputs found
Using edit distance to analyse errors in a natural language to logic translation corpus
We have assembled a large corpus of student submissions to an automatic grading system, where the subject matter involves the translation of natural language sentences into propositional logic. Of the 2.3 million translation instances in the corpus, 286,000 (approximately 12%) are categorized as being in error. We want to understand the nature of the errors that students make, so that we can develop tools and supporting infrastructure that help students with the problems that these errors represent.
With this aim in mind, this paper describes an analysis of a significant proportion of the data, using edit distance between incorrect answers and their corresponding correct solutions, and the associated edit sequences, as a means of organising the data and detecting categories of errors. We demonstrate that a large proportion of errors can be accounted for by means of a small number of relatively simple error types, and that the method draws attention to interesting phenomena in the data set
Dendritic cells exposed to Human Immunodeficiency Virus-1 transmit a vigorous cytopathic infection to CD4+ T cells
Cameron, P.U., Freudenthal, P.S., Barker, J.M., Gezelter, S., Inaba, K., and Steinman, R.M. Dendritic cells exposed to Human Immunodeficiency Virus-1 transmit a vigorous cytopathic infection to CD4+ T cells. Science 257: 383-387, 1992https://digitalcommons.rockefeller.edu/historical-scientific-reports/1032/thumbnail.jp
Changes in muscle cell cation regulation and meat quality traits are associated with genetic selection for high body weight and meat yield in broiler chickens
Between-breed genetic variation for muscle and meat quality traits was determined at eight weeks of age in 34 lines of purebred commercial broiler and layer lines and traditional breeds (categories) of chickens. Between-breed genetic variation for plasma ion concentrations and element concentration in muscle dry matter and ash were determined. Plasma from broilers had higher concentrations of Na+, K+, Mg++, total and free Ca++ and lower free:total Ca++ than plasma from layer and traditional lines. Muscle from broilers contained more Na and higher concentrations of K, Mg and Ca per mg of ash but not of dry matter compared with layer and traditional lines. In comparison with layer and traditional lines, broiler genotypes were over three times heavier, their plasma creatine kinase activity (CK), a marker of muscle tissue damage, was higher, their breast muscle colour was lighter (L*) and less red (a*) and yellow (b*) in appearance, the initial and final pH of their muscles were lower, the pH change was higher and their breast muscle was more tender. Thus, genetic selection for broiler traits has markedly altered cation regulation in muscle cells and may be associated with changes in muscle cell function and the development of pathology and meat quality problems
A rapid multi-disciplinary biodiversity assessment of the Kamdebooberge (Sneeuberg, Eastern Cape, South Africa): implications for conservation
Botanical work since 2008 on the Sleeping Giant section of the Kamdebooberge (Sneeuberg mountain complex, Eastern Cape, South Africa) has indicated that these mountains may be of significant conservation value. Accordingly, a precursory, rapid multi-disciplinary biodiversity assessment was undertaken in January 2011, focusing on plants, tetrapod vertebrates and leafhoppers. The botanical results confirm the Kamdebooberge as being of high botanical conservation value, hosting three strict endemics, healthy populations of five other Sneeuberg endemics, and fynbos communities comprising species not found elsewhere in the Sneeuberg. The Kamdebooberge are important for herpetofauna (excluding serpentoids) and mammals, hosting several range-restricted and regional endemics. The expedition uncovered three new leafhopper species, together with several species previously only known from the Cape Floristic Region. Further detailed faunal work may provide further interesting results from these mountains, which show a high conservation value unique to the southern Escarpment
Evaluation of Beef Steak Flavor Development in Vacuum Rollstock Packaging Under Two Lighting Sources
The objective of this study was to determine the influence of lighting type and display duration on flavor development in multiple beef muscles. Paired beef top sirloin butts, strip loins, and tenderloins were collected from USDA Low Choice carcasses (Small00 to Small100 marbling score, n=16). Subprimals were wet aged in the absence of light for 7 d postmortem at 0°C to 4°C before being fabricated into 2.5-cm steaks representing the Gluteus medius, Longissimus lumborum (LL), and Psoas major. Steaks were packaged individually in vacuum rollstock packaging and assigned to either light-emitting diode (LED) or fluorescent (FLUR) display cases for a display period of 0, 2, 6, or 10 d. All steaks were assigned to either trained descriptive panel analysis (n=384) or volatile compound analysis (n=384) and cooked to a medium degree of doneness (71°C). Two-way interactions occurred between lighting type and display duration, showing increased tenderness sooner during display for LED steaks, and lower umami intensity in FLUR steaks after 10 d (P<0.001). Lighting and muscle type showed more tender LL and Psoas major steaks in LED lighting (P≤0.001). Lighting and display duration interactions also showed increased concentrations of 2,3-butanedione under FLUR light and ethyl benzene under LED display (P≤0.043), whereas lighting and muscle type showed greater concentrations of alcohols and carboxylic acids in LL steaks under LED lighting (P≤0.046). Furthermore, discriminant function analyses were per-formed, suggesting that the most successful retail display period was within 2 to 6 d, with no difference between lighting types (P=0.212). Overall, these data reveal little differentiation between lighting types, implying that newer LED lighting does not detrimentally influence beef quality when vacuum packaging is utilized
A Multi-wavelength analysis of M81: insight on the nature of Arp's loop
Context: The optical ring like structure detected by Arp (1965) around M81
(commonly referenced as "Arp's loop") represents one of the most spectacular
feature observed in nearby galaxies. Arp's loop is commonly interpreted as a
tail resulting from the tidal interaction between M81 and M82. However, since
its discovery the nature of this feature has remained controversial. Aims: Our
primary purpose was to identify the sources of optical and infrared emission
observed in Arp's loop. Methods: The morphology of the Arp's loop has been
investigated with deep wide-field optical images. We also measured its colors
using IRAS and Spitzer-MIPS infrared images and compared them with those of the
disk of M81 and Galactic dust cirrus that fills the area where M81 is located.
Results: Optical images reveal that this peculiar object has a filamentary
structure characterized by many dust features overlapping M81's field. The
ratios of far-infrared fluxes and the estimated dust-to-gas ratios indicate the
infrared emission of Arp's loop is dominated by the contribution of cold dust
that is most likely from Galactic cirrus. Conclusions: The above results
suggest that the light observed at optical wavelengths is a combination of
emission from i) a few recent star forming regions located close to M81, where
both bright UV complexes and peaks in the HI distribution are found, ii) the
extended disk of M81 and iii) scattered light from the same Galactic cirrus
that is responsible for the bulk of the far infrared emission.Comment: 7 pages, 7 figures, accepted for publication by A&
Flavor Development of Individually Vacuum-Packaged Beef Steaks During Extended Wet Aging
The objective of the study was to determine the effect of extended aging on the flavor development of various muscles, individually stored in vacuum rollstock packaging. Strip loins, paired tenderloins, and top sirloin butts (n=48) from USDA Low Choice carcasses (Small00 to Small100 marbling score, n=16). Subprimals were wet-aged in the absence of light for 28 d postmortem before fabrication into 2.54 cm steaks representing the longissimus lumborum (LL), psoas major (PM), and gluteus medius (GM). Steaks were individually packaged in vacuum rollstock packaging and assigned to an additional aging time of 28, 35, 42, 49, or 56 d. Cut steaks (n=240/test) were designated to trained descriptive panel analysis or volatile compound analysis. No interactions occurred for trained sensory analysis, but a main effect of days of age (P≤0.033) showed the greatest effect on negatively associated attributes, including liver-like, oxidized, fishy, bitter, and sour, after 42 d of aging. A main effect of muscle type also occurred (P≤0.040) for flavor attributes, in which GM and PM samples scored higher in off-flavor attributes compared with LL samples, including flavors such as liver-like, oxidized, and sour. An interaction between muscle type and days of age occurred for 2-pentyl-furan (P=0.021). One compound—3 hydroxy-2 butanone—was affected by muscle type (P=0.009). However, most compounds were affected by days of age (P≤0.046), in which compounds related to off-flavors increased in concentrations the most after 49 d. Additionally, discriminant function analyses were performed, suggesting the most effective aging time for individual steaks to be under 49 d when considering loadings for volatile compounds and flavor attributes corresponding with days of age. Overall, these data suggest individual packaging of GM, LL, and PM muscles is most optimal for up to 42 or49 d of age without a large impact from the presence of off-flavors, thus providing food service establishments the opportunity to individually package beef steaks for an extended period while maintaining consumer satisfaction through optimal flavor
A multiwavelength analysis of the clumpy FIR-bright sources in M33
We present a multiwavelength study of a sample of far-infrared (FIR) sources detected on the Herschel broad-band maps of the nearby galaxy M33. We perform source photometry on the FIR maps as well as mid-infrared (MIR), Halpha, far-ultraviolet and integrated H I and CO line emission maps. By fitting MIR/FIR dust emission spectra, the source dust masses, temperatures and luminosities are inferred. The sources are classified based on their Halpha morphology (sub-structured versus not-substructured) and on whether they have a significant CO detection (S/N > 3sigma). We find that the sources have dust masses in the range 102-104 M&sun; and that they present significant differences in their inferred dust/star formation/gas parameters depending on their Halpha morphology and CO detection classification. The results suggests differences in the evolutionary states or in the number of embedded H II regions between the sub-samples. The source background-subtracted dust emission seems to be predominantly powered by local star formation, as indicated by a strong correlation between the dust luminosity and the dust-corrected Halpha luminosity and the fact that the extrapolated young stellar luminosity is high enough to account for the observed dust emission. Finally, we do not find a strong correlation between the dust-corrected Halpha luminosity and the dust mass of the sources, consistent with previous results on the breakdown of simple scaling relations at sub-kpc scales. However, the scatter in the relation is significantly reduced by correcting the Halpha luminosity for the age of the young stellar populations in the star-forming regions
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Lifetime Pesticide Use and Telomere Shortening among Male Pesticide Applicators in the Agricultural Health Study
Background: Telomere length (TL) in surrogate tissues may be influenced by environmental exposures. Objective: We aimed to determine whether lifetime pesticides use is associated with buccal cell TL. Methods: We examined buccal cell TL in relation to lifetime use of 48 pesticides for 1,234 cancer-free white male pesticide applicators in the Agricultural Health Study (AHS), a prospective cohort study of 57,310 licensed pesticide applicators. Participants provided detailed information on lifetime use of 50 pesticides at enrollment (1993–1997). Buccal cells were collected from 1999 to 2006. Relative telomere length (RTL) was measured using quantitative real-time polymerase chain reaction. We used linear regression modeling to evaluate the associations between specific pesticides and the logarithm of RTL, adjusting for age at buccal cell collection, state of residence, applicator license type, chewing tobacco use, and total lifetime days of all pesticide use. Results: The mean RTL for participants decreased significantly in association with increased lifetime days of pesticide use for alachlor (p = 0.002), 2,4-dichlorophenoxyacetic acid (2,4-D; p = 0.004), metolachlor (p = 0.01), trifluralin (p = 0.05), permethrin (for animal application) (p = 0.02), and toxaphene (p = 0.04). A similar pattern of RTL shortening was observed with the metric lifetime intensity-weighted days of pesticide use. For dichlorodiphenyltrichloroethane (DDT), we observed significant RTL shortening for lifetime intensity-weighted days (p = 0.04), but not for lifetime days of DDT use (p = 0.08). No significant RTL lengthening was observed for any pesticide. Conclusion: Seven pesticides previously associated with cancer risk in the epidemiologic literature were inversely associated with RTL in buccal cell DNA among cancer-free pesticide applicators. Replication of these findings is needed because we cannot rule out chance or fully rule out bias
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