5,330 research outputs found

    Western Kingbird (Tyrannus verticalis): Recently Established Breeding Bird in Arkansas

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    The Western Kingbird (Tyrannus verticalis) has nested for six consecutive years in Arkansas since 1998. Eleven nests of this species were observed in the summer of 2003 in urban areas of Fort Smith (Sebastian Co.) and Van Buren (Crawford Co.). All nests were on human-made structures. Of the 11, seven (64%) were located on power stations and the remaining four (36%) were on light posts. Mean nest height was 7.92 m (n = 11nests) and the mean width of nest poles was 31.18 cm (n= 4). Nest building lasted 12 to 13 days (mean = 12.5 days, n = 2 nests). The attentive period of female parents (time spent on nest at a stretch during incubation) and their inattentive period were highly variable and averaged 11.97 minutes and 4.08 minutes respectively. The male stayed in close proximity of the nest throughout the nest building and incubation phases. Incubation period was estimated to be 17 days (n = 2 nests). Nesting success (percentage of nests that fledged young) was 72.7% (n = 11 nests). The average number of young fledged per successful nest was 3.37 (n =8) and the average number fledged over all nests was 2.45 (n = 11). In all nests, only the female participated in nest-building and incubation. Fledging occurred 13 to 14 days after hatching (mean =13.5 days, n = 2 nests)

    Baryon Exotics in the Quark Model, the Skyrme Model and QCD

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    We identify the quantum numbers of baryon exotics in the Quark Model, the Skyrme Model and QCD, and show that they agree for arbitrary colors and flavors. We define exoticness, E, which can be used to classify the states. The exotic baryons include the recently discovered qqqq qbar pentaquarks (E=1), as well as exotic baryons with additional q qbar pairs (E >=1). The mass formula for non-exotic and exotic baryons is given as an expansion in 1/N, and allows one to relate the moment of inertia of the Skyrme soliton to the mass of a constituent quark

    IS THERE FAMILY POLICY?

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    Agricultural and Food Policy,

    Making the Connection: Reinforcing Hands-on Learning Through Hands-on Writing

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    Traditionally, the goal of experiential learning is to allow students to learn through hands-on experience. Recently, suitable assessment and evaluation techniques of students in online learning environments have garnered a great deal of attention as to best practices in experiential learning based courses. This study analyzes assessment and evaluation of student learning in an undergraduate-level Pocket PC course, centred on experiential learning in an online learning environment. This study will (1) identify hands-on activities that can be implemented in an experiential learning environment; (2) examine the effectiveness of assessment tools; and (3) examine student perceptions of course activities.Traditionally, the goal of experiential learning is to allow students to learn through hands-on experience. Recently, suitable assessment and evaluation techniques of students in online learning environments have garnered a great deal of attention as to best practices in experiential learning based courses. This study analyzes assessment and evaluation of student learning in an undergraduate-level Pocket PC course, centred on experiential learning in an online learning environment. This study will (1) identify hands-on activities that can be implemented in an experiential learning environment; (2) examine the effectiveness of assessment tools; and (3) examine student perceptions of course activities

    Umbelliferone and esculetin protect against N-nitrosodiethylamine-induced hepatotoxicity in rats

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    N-nitrosodiethylamine (NDEA), a nitrosamine compound, is known to cause liver damage through the generation of reactive oxygen species (ROS), resulting in oxidative damage to macromolecules such as DNA, and the consequent development of cancer. The present study examines the protective effects of two antioxidant coumarin compounds umbelliferone (Umb) and esculetin (Esc) against NDEA-induced hepatotoxicity when administered in the diet to male Wistar rats. The results show that treatment with Umb (0.5%w/w) and Esc (0.5%w/w) in the diet for 7 days significantly attenuates NDEA-induced liver damage, lowering serum alanine transaminase (ALT) levels, decreasing hepatic lipid peroxidation, and restoring total glutathione levels. To investigate the mechanism for the observed protective effect, the levels of the key protective enzymes NAD(P)H: quinone oxidoreductase 1 (NQO1), heme oxygenase (HO1), and glutathione S-transferase Pi (GSTP1) were measured by Western blotting following Umb and Esc administration. The results showed that Umb and Esc administration significantly increased the expression of NQO1 by 3.6- and 2.7-fold, HO1 by 2.7- and 3.2-fold, and GSTP1 by 2.8- and 3.2-fold, respectively. In conclusion, Umb and Esc are capable of protecting liver from NDEA-induced hepatotoxicity, and this is associated with the induction of protective enzymes

    Continued communication – maximising the business potential of communications through Web 2.0

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    This paper is concerned with Continued Communication, a Northumbria University led co-operative inquiry, critically evaluating a central research question: how can organisations maximise the potential of their communications, taking into account the impact of the individual. This paper provides a high level discussion of the research and outputs of the Continued Communication’s UK group. It discusses the complex dimensions of communication; organisational requirements, individual agendas, and communication channels/tools

    Observation of coherent delocalized phonon-like modes in DNA under physiological conditions

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    Underdamped terahertz-frequency delocalized phonon-like modes have long been suggested to play a role in the biological function of DNA. Such phonon modes involve the collective motion of many atoms and are prerequisite to understanding the molecular nature of macroscopic conformational changes and related biochemical phenomena. Initial predictions were based on simple theoretical models of DNA. However, such models do not take into account strong interactions with the surrounding water, which is likely to cause phonon modes to be heavily damped and localized. Here we apply state-of-the-art femtosecond optical Kerr effect spectroscopy, which is currently the only technique capable of taking low-frequency (GHz to THz) vibrational spectra in solution. We are able to demonstrate that phonon modes involving the hydrogen bond network between the strands exist in DNA at physiologically relevant conditions. In addition, the dynamics of the solvating water molecules is slowed down by about a factor of 20 compared with the bulk
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