Prey Selection and Bioenergetics of Captive Screech Owls

Author Institution: Department of Zoology and Institute of Environmental Sciences, Miami UniversityScreech owls appeared to select meadow voles {Microtus pennsylvanicus) as a primary food source, although deer mice (Peromyscus maniculatus) were apparently equally abundant and vulnerable. This feeding behavior resulted in a larger energy reward. A mean ingestion rate of 0.37 kcal/g live wt/day was derived from average values of 29-3 g live wt/day for Microtus as prey and only 11.3 g live wt/day for Peromyscus. Assimilation energy (ingestion-pellets-feces) was 0.28 kcal/g live wt/day; the mean assimilation efficiency (ingested energy-pellet energy-fecal energy/ingested energy x 100) was 76%. These findings support the hypothesis that a large energy reward is a prime factor in prey selection

Implementation Workshop: High Performance Work Organizations

A report on findings from the first Lean Aircraft Initiative (LAI) Implementation Workshop held on February 5-6, 1997. The report is not a "cookbook" or a "how to" manual. Rather, it is a summary of the first phase in a learning process. It is designed to codify lessons learned, facilitate diffusion among people not at the session, and set the stage for further learning about implementation.Lean Aerospace Initiativ

A study of the role of nature conservation law enforcement officers as facilitators of environmental education

This study explores the potential roles of a sample of 18 nature conservation law enforcement officers, as facilitators of environmental education. More specifically it examines their attitudes towards their dual duties of enforcing laws and providing extension services. Attitudes were examined by means of qualitative data analysis from semi-structured interviews. Officers' environmental attitudes, as well the relative emphasis placed on law enforcement and extension, and their own perspectives of working with communities, are explored. The historical and cultural context of officers' work, as well as worldviews and personality traits are also discussed. Certain recommendations regarding officers' roles as facilitors of environmental education are made

Differential coupling of the extreme C-terminus of G protein α subunits to the G protein-coupled melatonin receptors

AbstractMelatonin receptors interact with pertussis toxin-sensitive G proteins to inhibit adenylate cyclase. However, the G protein coupling profiles of melatonin receptor subtypes have not been fully characterised and alternative G protein coupling is evident. The five C-terminal residues of Gα subunits confer coupling specificity to G protein-coupled receptors. This report outlines the use of Gαs chimaeras to alter the signal output of human melatonin receptors and investigate their interaction with the C-termini of Gα subunits. The Gαs portion of the chimaeras confers the ability to activate adenylate cyclase leading to cyclic AMP production. Co-transfection of HEK293 cells expressing MT1 or MT2 melatonin receptors with Gαs chimaeras and a cyclic AMP activated luciferase construct provided a convenient and sensitive assay system for identification of receptor recognition of Gα C-termini. Luciferase assay sensitivity was compared with measurement of cyclic AMP elevations by radioimmunoassay. Differential interactions of the melatonin receptor subtypes with Gα chimaeras were observed. Temporal and kinetic parameters of cyclic AMP responses measured by cyclic AMP radioimmunoassay varied depending on the Gαs chimaeras coupled. Recognition of the C-terminal five amino acids of the Gα subunit is a requisite for coupling to a receptor, but it is not the sole determinant

The secreted triose phosphate isomerase of Brugia malayi is required to sustain microfilaria production in vivo

Human lymphatic filariasis is a major tropical disease transmitted through mosquito vectors which take up microfilarial larvae from the blood of infected subjects. Microfilariae are produced by long-lived adult parasites, which also release a suite of excretory-secretory products that have recently been subject to in-depth proteomic analysis. Surprisingly, the most abundant secreted protein of adult Brugia malayi is triose phosphate isomerase (TPI), a glycolytic enzyme usually associated with the cytosol. We now show that while TPI is a prominent target of the antibody response to infection, there is little antibody-mediated inhibition of catalytic activity by polyclonal sera. We generated a panel of twenty-three anti-TPI monoclonal antibodies and found only two were able to block TPI enzymatic activity. Immunisation of jirds with B. malayi TPI, or mice with the homologous protein from the rodent filaria Litomosoides sigmodontis, failed to induce neutralising antibodies or protective immunity. In contrast, passive transfer of neutralising monoclonal antibody to mice prior to implantation with adult B. malayi resulted in 60–70% reductions in microfilarial levels in vivo and both oocyte and microfilarial production by individual adult females. The loss of fecundity was accompanied by reduced IFNγ expression by CD4+ T cells and a higher proportion of macrophages at the site of infection. Thus, enzymatically active TPI plays an important role in the transmission cycle of B. malayi filarial parasites and is identified as a potential target for immunological and pharmacological intervention against filarial infections

Reference Array and Design Consideration for the next-generation Event Horizon Telescope

We describe the process to design, architect, and implement a transformative enhancement of the Event Horizon Telescope (ngEHT). This program - the next-generation Event Horizon Telescope (ngEHT) - will form a networked global array of radio dishes capable of making high-fidelity real-time movies of supermassive black holes (SMBH) and their emanating jets. This builds upon the EHT principally by deploying additional modest-diameter dishes to optimized geographic locations to enhance the current global mm/submm wavelength Very Long Baseline Interferometric (VLBI) array, which has, to date, utilized mostly pre-existing radio telescopes. The ngEHT program further focuses on observing at three frequencies simultaneously for increased sensitivity and Fourier spatial frequency coverage. Here, the concept, science goals, design considerations, station siting and instrument prototyping are discussed, and a preliminary reference array to be implemented in phases is described.Comment: Submitted to the journal Galaxie

Killer whales and marine mammal trends in the North Pacific : a re-examination of evidence for sequential megafauna collapse and the prey-switching hypothesis

This paper is not subject to U.S. copyright. The definitive version was published in Marine Mammal Science 23 (2007): 766–802, doi:10.1111/j.1748-7692.2006.00093.x.Springer et al. (2003) contend that sequential declines occurred in North Pacific populations of harbor and fur seals, Steller sea lions, and sea otters. They hypothesize that these were due to increased predation by killer whales, when industrial whaling's removal of large whales as a supposed primary food source precipitated a prey switch. Using a regional approach, we reexamined whale catch data, killer whale predation observations, and the current biomass and trends of potential prey, and found little support for the prey-switching hypothesis. Large whale biomass in the Bering Sea did not decline as much as suggested by Springer et al., and much of the reduction occurred 50–100 yr ago, well before the declines of pinnipeds and sea otters began; thus, the need to switch prey starting in the 1970s is doubtful. With the sole exception that the sea otter decline followed the decline of pinnipeds, the reported declines were not in fact sequential. Given this, it is unlikely that a sequential megafaunal collapse from whales to sea otters occurred. The spatial and temporal patterns of pinniped and sea otter population trends are more complex than Springer et al. suggest, and are often inconsistent with their hypothesis. Populations remained stable or increased in many areas, despite extensive historical whaling and high killer whale abundance. Furthermore, observed killer whale predation has largely involved pinnipeds and small cetaceans; there is little evidence that large whales were ever a major prey item in high latitudes. Small cetaceans (ignored by Springer et al.) were likely abundant throughout the period. Overall, we suggest that the Springer et al. hypothesis represents a misleading and simplistic view of events and trophic relationships within this complex marine ecosystem

Establishing a method to support academic and professional competence throughout an undergraduate radiography programme

Purpose: Radiography degree programmes are coming under increasing pressurefrom the community to ensure that graduates have not only the necessary academic developmentbut also the practice-based skills. This study aims to establish a method of monitoringstudents’ progress towards, and ability to meet, academic and professional competencesthroughout a radiography programme.Methods: Questionnaires were designed for students and academic staff to determine thestages and standards of progress of competence development, and to inform the review processof the current assessment tools throughout the programme. A literature search identifiedthe appropriate pedagogy as a basis for devising the method. Another questionnaire was distributedto overseas radiography institutions to gain insights into other assessment practicesto validate the framework.Results and discussion: It was established that years of study rather than semester periodswere appropriate to allow students to meet the standards. Discrepancies were noted in theexpectations between academic staff (higher expectations) and students (more realistic) interms of the pace of development expected. As students progress at different rates, and donot experience the same clinical exposure, their ability to meet expectations may differand so both sets of expectations were combined as a range of criteria. A multi-dimensionalassessment approach should be adequate to gauge students’ progress but time and resourceeffectiveness has not yet been addressed. The portfolio was identified as the pedagogy capableof integrating all the competence assessment tools, linked by reflective writing, to gatherindividual outcomes into a whole, and form a holistic framework.Outcome: The portfolio framework will initially run as a voluntary activity and standards ofprogress corresponding to the students’ stages will be delivered to participants in advance.Participants will be required to select materials and reflect on these, as evidence of development.Faculty members will provide support and feedback to students and oversee the wholeprocess

Cortical Mechanics and Meiosis II Completion in Mammalian Oocytes Are Mediated by Myosin-II and Ezrin-Radixin-Moesin (ERM) Proteins

Analysis of mouse oocyte mechanics shows that effective tension drops 6-fold from prophase I to metaphase II; the metaphase II egg has a 2.5-fold tension differential between the cortex over the spindle and the opposite cortex. Manipulation of actin, myosin-II, or ERMs alters tension levels and induces spindle abnormalities during meiosis II