1,566 research outputs found

    A complete record from colonization to extinction reveals density dependence and the importance of winter conditions for a population of the silvery blue, Glaucopsyche lygdamus.

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    Butterflies in the family Lycaenidac are often the focus of conservation efforts. However, our understanding of lycaenid population dynamics has been limited to relatively few examples of long-term monitoring data that have been reported. Here, factors associated with population regulation are investigated using a complete record of a single population of the silvery blue, Glaucopsyche lygdamus Doubleday (Lepidoptera: Lycaenidae). Adults of G. lygdamus were first observed in an annual grassland near Davis, California, in 1982 and were last seen in 2003. Relationships between inter-annual variation in abundance and climatic variables were examined, accounting for density dependent effects. Significant effects of both negative density dependence and climatic variation were detected, particularly precipitation and temperature during winter months. Variation in precipitation, the strongest predictor of abundance, was associated directly and positively with butterfly abundance in the same year. Winter temperatures had a negative effect in the same year, but had a lagged, positive effect on abundance in the subsequent year. Mechanistic hypotheses are posed that include climatic effects mediated through both larval and adult plant resources

    Raising Dairy Calves

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    The average age at which the dairy cow In the United States either dies, Is butchered, becomes a non·breeder, or for some other reason ceases to be a producer, Is six years. To many this figure may appear low, for cows are sometimes productive at ten or twelve years and even at fifteen or sixteen years and older. These cases of exceptlonal longevity are notable and they appear to be numerous, but the number of cows which die previous to th~lr sixth year Is far greater. Studies of many herds, of both grades and purebreds, under all conditions, thruout the country, confirm the statement that the productive life of the average cow terminates when she 111 six years old. Dairy heifers become producers when two years old and thus their average production period continues for four years. There are In this country approximately 24,000,000 dairy cows; one-fourth, or 6,000,000, drop out of production each year and must he replaced. It Is safe to assume that 18,000,000 calves are born annually; probably one·half of them are bulls and from the remaining 9,000,000 heifer calves must come the two·year old heifers to replace the 6,000,000 discarded cows

    Eg5 steps it up!

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    Understanding how molecular motors generate force and move microtubules in mitosis is essential to understanding the physical mechanism of cell division. Recent measurements have shown that one mitotic kinesin superfamily member, Eg5, is mechanically processive and capable of crosslinking and sliding microtubules in vitro. In this review, we highlight recent work that explores how Eg5 functions under load, with an emphasis on the nanomechanical properties of single enzymes

    Use of Whatman-41 filters in air quality sampling networks (with applications to elemental analysis)

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    The operation of a 16-site parallel high volume air sampling network with glass fiber filters on one unit and Whatman-41 filters on the other is reported. The network data and data from several other experiments indicate that (1) Sampler-to-sampler and filter-to-filter variabilities are small; (2) hygroscopic affinity of Whatman-41 filters need not introduce errors; and (3) suspended particulate samples from glass fiber filters averaged slightly, but not statistically significantly, higher than from Whatman-41-filters. The results obtained demonstrate the practicability of Whatman-41 filters for air quality monitoring and elemental analysis

    Combined optical trapping and single-molecule fluorescence

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    BACKGROUND: Two of the mainstay techniques in single-molecule research are optical trapping and single-molecule fluorescence. Previous attempts to combine these techniques in a single experiment – and on a single macromolecule of interest – have met with little success, because the light intensity within an optical trap is more than ten orders of magnitude greater than the light emitted by a single fluorophore. Instead, the two techniques have been employed sequentially, or spatially separated by distances of several micrometers within the sample, imposing experimental restrictions that limit the utility of the combined method. Here, we report the development of an instrument capable of true, simultaneous, spatially coincident optical trapping and single-molecule fluorescence. RESULTS: We demonstrate the capability of the apparatus by studying force-induced strand separation of a rhodamine-labeled, 15 base-pair segment of double-stranded DNA, with force applied perpendicular to the axis of the DNA molecule. As expected, we observed abrupt mechanical transitions corresponding to the unzipping of DNA at a critical force. Transitions occurred concomitant with changes in the fluorescence of dyes attached at the duplex ends, which became unquenched upon strand separation. CONCLUSIONS: Through careful optical design, the use of high-performance spectral notch filters, a judicious choice of fluorophores, and the rapid acquisition of data gained by computer-automating the experiment, it is possible to perform combined optical trapping and single-molecule fluorescence. This opens the door to many types of experiment that employ optical traps to supply controlled external loads while fluorescent molecules report concurrent information about macromolecular structure

    Synchronous Meteorological Satellite Phase B Study Report

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    Design of base line system for synchronous meteorological satellit

    iteRates: An R Package for Implementing a Parametric Rate Comparison on Phylogenetic Trees

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    Patterns of diversification rate variation detected in phylogenetic hypotheses are frequently used to infer historical, ecological, and evolutionary processes. The parametric rate comparison (PRC) is a method for detecting rate variation in trees that models branch lengths as random variables drawn from familiar statistical distributions. iteRates is a library of functions for the R statistical computing environment for implementing PRC on phylogenetic trees. Here, we describe some of the functions in iteRates for subtree identification, tree manipulation, applying the PRC and K-clades PRC analyses, and conducting a whole-tree randomization test

    Higher Education Strategy in Responding to the Generative AI Revolution Decolonising the Standard Response and Action Planning Protocols

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    Background: The Generative Artifical Intelligence (AI) revolution is here, and the availability of resources such as ChatGPT has triggered rapid responses, actions, and strategy to address the implications this has on education in the United Kingdom (UK). ChatGPT and other Generative AI provisions are viewed as both problematic and beneficial by Higher Education Institutes (HEI’s). Alongside HEI’s, Higher Education England (HEE) Technology Enhanced Learning (TEL) forums are just 1 of many additional UK national groups prioritising the discussion, Continual Professional Development (CPD), and strategical approaches to analysing Generative AI, in determining how it should be addressed in education and practice. In terms of standard practice at London South Bank University (LSBU), the planning of projects and research to explore new technology lies predominantly with those deemed as the most “skilled”, “technical” or “aware” of the technology. People who are in specific roles within the institute are expected to “lead” on strategy, and this onus of responsibility often remains with them throughout the process from start to finish. Recognising the imbalance of power and the benefits of privilege this practice could create, a decision was made to explore and propose re-design of the current protocols in place at LSBU. Aim: Demonstrate the inclusion of a Decolonising step at the earliest designing stage of the project, to influence a practice change in how a HEI could respond to major items affecting education and any subsequent action-planning or project designing. Method: 3 academic members of staff, and 3 undergraduate students, of Black, Asian, African or Minority ethnicity, will be recruited. Individual and group sessions will be conducted using Microsoft Teams. Sessions will involve the participants leading on the discussion and development of the project proposal and associated documents being used in the larger study. This will occur between 19th May – 1st June 2023, after which the project proposal will be registered with the LSBU research ethics committee and internal registration system (Haplo). The Decolonising strategy and effects will be appraised by an independent investigator making objective comparisons to a version of the project protocol originally written by the Principal Investigator as a lone researcher. Themes and major highlights to demonstrate these comparisons, will be presented as the outcome for this project. All results and recommendations will be ready for presentation by no later than 15th June 2023. Expected Outcomes: Recommendations based on the outcome could feasibly affect changes in the future strategy for responding to major items requiring adaptation and evolution in education/practices, and potential other general and/or specific response/action-planning protocols, at London South Bank University. Additional information: This project forms part of a larger LSBU Generative AI project to explore a potential solution to the issues surrounding Generative AI in Higher Education
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