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"Harland, M."
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Ethnic Identity and the Archaeology of the aduentus Saxonum
For centuries, archaeologists have excavated the soils of Britain to uncover finds from the early medieval past. These finds have been used to reconstruct the alleged communities, migration patterns, and expressions of identity of coherent groups who can be regarded as ethnic 'Anglo-Saxons'. Even in the modern day, when social constructionism has been largely accepted by scholars, this paradigm still persists. This book challenges the ethnic paradigm. As the first historiographical study of approaches to ethnic identity in modern 'Anglo-Saxon' archaeology, it reveals these approaches to be incompatible with current scholarly understandings of ethnicity. Drawing upon post-structuralist approaches to self and community, it highlights the empirical difficulties the archaeology of ethnicity in early medieval Britain faces, and proposes steps toward an alternative understanding of the role played by the communities of lowland Britain - both migrants from across the North Sea and those already present - in transforming the Roman world.
eBook
Enhancing Hubble's vision : service missions that expanded our view of the universe
\"After a 20-year struggle to place a large, sophisticated optical telescope in orbit the Hubble Space Telescope was finally launched in 1990, though its primary mirror was soon found to be flawed. A dramatic mission in 1993 installed corrective optics so that the intended science program could finally begin. Those events are related in a companion to this book, The Hubble Space Telescope: From Concept to Success. Enhancing Hubble's Vision: Service Missions That Expanded Our View of the Universe tells the story of the four missions between 1997 and 2009 that repaired, serviced and upgraded the instruments on the telescope to maintain its state-of-the-art capabilities. It draws on first hand interviews with those closely involved in the project. The spacewalking skills and experiences gained from maintaining and upgrading Hubble had direct application to the construction of the International Space Station and help with its maintenance. These skills can be applied to future human and robotic satellite servicing and maintenance activities as well, not only in Earth orbit but at locations deeper in space. Originally intended to operate for fifteen years, Hubble has just passed its 25th anniversary, and there is every expectation that it will survive for thirty years. Despite its early problems, the Hubble Space Telescope has become a lasting legacy of the Space Shuttle program, and indeed is a national treasure\"--Back cover.
Book
Ethnic Identity and the Archaeology of the aduentus Saxonum
For centuries, archaeologists have excavated the soils of Britain to uncover finds from the early medieval past. These finds have been used to reconstruct the alleged communities, migration patterns, and expressions of identity of coherent groups who can be regarded as ethnic 'Anglo-Saxons'. Even in the modern day, when social constructionism has been largely accepted by scholars, this paradigm still persists.
This book challenges the ethnic paradigm. As the first historiographical study of approaches to ethnic identity in modern 'Anglo-Saxon' archaeology, it reveals these approaches to be incompatible with current scholarly understandings of ethnicity. Drawing upon post-structuralist approaches to self and community, it highlights the empirical difficulties the archaeology of ethnicity in early medieval Britain faces, and proposes steps toward an alternative understanding of the role played by the communities of lowland Britain - both migrants from across the North Sea and those already present - in transforming the Roman world.
eBook
Impacts of soil nutrition on floral traits, pollinator attraction, and fitness in cucumbers (Cucumis sativus L.)
Annual plants allocate soil nutrients to floral display and pollinator rewards to ensure pollination success in a single season. Nitrogen and phosphorus are critical soil nutrients whose levels are altered by intensive land use that may affect plants’ fitness via pollinator attractiveness through floral display and rewards. In a controlled greenhouse study, we studied in cucumbers (
Cucumis sativus
) how changes in soil nitrogen and phosphorus influence floral traits, including nectar and pollen reward composition. We evaluated how these traits affect bumble bee (
Bombus impatiens
, an important cucumber pollinator) visitation and ultimately fruit yield. While increasing nitrogen and phosphorus increased growth and floral display, excess nitrogen created an asymptotic or negative effect, which was mitigated by increasing phosphorus. Male floral traits exhibited higher plasticity in responses to changes in soil nutrients than female flowers. At 4:1 nitrogen:phosphorus ratios, male flowers presented increased nectar volume and pollen number resulting in increased bumble bee visitation. Interestingly, other pollinator rewards remained consistent across all soil treatments: male and female nectar sugar composition, female nectar volume, and pollen protein and lipid concentrations. Therefore, although cucumber pollination success was buffered in conditions of nutrient stress, highly skewed nitrogen:phosphorus soil ratios reduced plant fitness via reduced numbers of flowers and reward quantity, pollinator attraction, and ultimately yield.
Journal Article
FloralArea: AI-powered algorithm for automated calculation of floral area from flower images to support plant and pollinator research
Floral area is a major predictor of the attractiveness of a flowering plant for pollinators, yet the measurement of floral area is time-consuming and inconsistent across studies. Here, we developed an AI-powered algorithm, FloralArea, to automate floral area measurement from an image. The FloralArea algorithm has two main components: an object segmentation module and an area estimation module. The object segmentation module extracts the pixels of flowers and the reference object in an image. The area estimation module predicts floral area based on the ratio between flower and reference object pixels. We fine-tuned two YOLOv8 segmentation models for flower and reference object segmentation. The flower segmentation model achieved moderate precision, recall, mAP0.5, and mAP0.5-0.95 of 0.794, 0.68, 0.741, and 0.455 on the test dataset, while the reference object model achieved an impressive performance of 0.907, 0.940, 0.933, and 0.832. We evaluated FloralArea using 75 images of flowering plants. We used ImageJ to calculate the actual floral area for all the images and compared them with the predicted floral area from FloralArea. The predicted floral area correlated well with the measured floral area with a coefficient of determination (R 2 ) of 0.93 and a root mean square error of 20.58 cm 2 . The FloralArea algorithm reduced the time it takes to calculate floral area from an image by 99.24% compared with traditional methods with image processing tools like ImageJ. By streamlining floral area estimation, the FloralArea algorithm provides a scalable, efficient, consistent, and accessible tool for researchers, particularly to aid in assessing plant attractiveness to different pollinator groups.
Journal Article
Emergent cellular self-organization and mechanosensation initiate follicle pattern in the avian skin
The spacing of hair in mammals and feathers in birds is one of the most apparent morphological features of the skin. This pattern arises when uniform fields of progenitor cells diversify their molecular fate while adopting higher-order structure. Using the nascent skin of the developing chicken embryo as a model system, we find that morphological and molecular symmetries are simultaneously broken by an emergent process of cellular self-organization. The key initiators of heterogeneity are dermal progenitors, which spontaneously aggregate through contractility-driven cellular pulling. Concurrently, this dermal cell aggregation triggers the mechanosensitive activation of β-catenin in adjacent epidermal cells, initiating the follicle gene expression program. Taken together, this mechanism provides a means of integrating mechanical and molecular perspectives of organ formation.
Journal Article
Macronutrient ratios in pollen shape bumble bee (Bombus impatiens) foraging strategies and floral preferences
To fuel their activities and rear their offspring, foraging bees must obtain a sufficient quality and quantity of nutritional resources from a diverse plant community. Pollen is the primary source of proteins and lipids for bees, and the concentrations of these nutrients in pollen can vary widely among host-plant species. Therefore we hypothesized that foraging decisions of bumble bees are driven by both the protein and lipid content of pollen. By successively reducing environmental and floral cues, we analyzed pollen-foraging preferences of Bombus impatiens in (i) host-plant species, (ii) pollen isolated from these host-plant species, and (iii) nutritionally modified single-source pollen diets encompassing a range of protein and lipid concentrations. In our semifield experiments, B. impatiens foragers exponentially increased their foraging rates of pollen from plant species with high protein: lipid (P:L) ratios; the most preferred plant species had the highest ratio (∼4.6:1). These preferences were confirmed in cage studies where, in pairwise comparisons in the absence of other floral cues, B. impatiens workers still preferred pollen with higher P:L ratios. Finally, when presented with nutritionally modified pollen, workers were most attracted to pollen with P:L ratios of 5:1 and 10:1, but increasing the protein or lipid concentration (while leaving ratios intact) reduced attraction. Thus, macronutritional ratios appear to be a primary factor driving bee pollen-foraging behavior and may explain observed patterns of host-plant visitation across the landscape. The nutritional quality of pollen resources should be taken into consideration when designing conservation habitats supporting bee populations.
Journal Article
Ethnic Identity and the Archaeology of the aduentus Saxonum
For centuries, archaeologists have excavated the soils of Britain to uncover finds from the early medieval past. These finds have been used to reconstruct the alleged communities, migration patterns, and expressions of identity of coherent groups who can be regarded as ethnic 'Anglo-Saxons'. Even in the modern day, when social constructionism has been largely accepted by scholars, this paradigm still persists. This book challenges the ethnic paradigm. As the first historiographical study of approaches to ethnic identity in modern 'Anglo-Saxon' archaeology, it reveals these approaches to be incompatible with current scholarly understandings of ethnicity. Drawing upon post-structuralist approaches to self and community, it highlights the empirical difficulties the archaeology of ethnicity in early medieval Britain faces, and proposes steps toward an alternative understanding of the role played by the communities of lowland Britain – both migrants from across the North Sea and those already present – in transforming the Roman world.
eBook
Pollen Protein: Lipid Macronutrient Ratios May Guide Broad Patterns of Bee Species Floral Preferences
Pollinator nutritional ecology provides insights into plant–pollinator interactions, coevolution, and the restoration of declining pollinator populations. Bees obtain their protein and lipid nutrient intake from pollen, which is essential for larval growth and development as well as adult health and reproduction. Our previous research revealed that pollen protein to lipid ratios (P:L) shape bumble bee foraging preferences among pollen host-plant species, and these preferred ratios link to bumble bee colony health and fitness. Yet, we are still in the early stages of integrating data on P:L ratios across plant and bee species. Here, using a standard laboratory protocol, we present over 80 plant species’ protein and lipid concentrations and P:L values, and we evaluate the P:L ratios of pollen collected by three bee species. We discuss the general phylogenetic, phenotypic, behavioral, and ecological trends observed in these P:L ratios that may drive plant–pollinator interactions; we also present future research questions to further strengthen the field of pollination nutritional ecology. This dataset provides a foundation for researchers studying the nutritional drivers of plant–pollinator interactions as well as for stakeholders developing planting schemes to best support pollinators.
Journal Article