2,943 research outputs found
Quantifying Human Dietary Change over the Last 30,000 Years
Dietary change has been linked to many aspects of human evolution over the last three million years, including tool use, brain size increase, aerobic capacity and gut biology. Furthermore, failure to adapt to dietary changes over the last 10,000 years has been implicated in a number of complex and chronic diseases including obesity, type II diabetes, some cancers and coronary heart disease. Such ‘diseases of modernity’ are more common in agrarian and industrial societies than among hunter-gatherers, and it has been argued that this is due to a mismatch between modern diets and the ancestral diets to which our metabolism should be optimised. The aims of this research have grown out of the qualitative studies that perpetuate narratives around human and hominin diets, particularly around the central theme of dietary mismatch and ‘paleo’-named diets. In this work, I investigate nutrient-level differences between modern post-industrial diets, modern hunter-gatherer diets, prehistoric (Palaeolithic, Neolithic and Bronze Age) diets reconstructed from archaeological data, clinical intervention diets, fad diets including The Paleo Diet, Keto Diet and Atkins Diet, fast food diets and milk. Using these data, I develop a hypothesis on the evolution of dietary choice. Modern diets are enriched for certain nutrients, for some of which we have strong taste avidities (e.g. sodium, sucrose, starch, certain fatty acids). By quantifying differences in inferred nutrient profiles between ancestral and modern diets, I examine the nutrients enriched in modern diets, the trajectories of nutrient composition change through time, what might be driving these changes, and why we have evolved taste preferences for some nutrients that in a modern setting are considered ‘unhealthy’. I also examine how nutrients correlate in ancestral foods and explore if avidities for nutrients enriched in modern diets would lead to healthy nutrient profiles in an ancestral setting
Status of Student Practice Rules \u3cem\u3ePeople v. Perez\u3c/em\u3e—An Initial Look at the Sixth Amendment
Despite the advent of the limited practice of law by law students as early as 1957, a California Court of Appeals in 1978 became the first court to examine the sixth amendment status of student representation in state criminal prosecutions. In People v. Perez, a California appellate court concluded that a lawyer-supervised law student, certified for limited practice by the California Student Practice Rules, is per se ineffective counsel in felony trials. Ostensibly to protect the defendant\u27s right to effective counsel, Perez struck down the student practice rules without considering the proper function of certification in sixth amendment analysis. Moreover, the court misapplied sixth amendment principles in concluding that the Constitution does not allow student representation in felony trials, irrespective of the presence of a supervising attorney at trial
Feeding Patterns and Attachment Ability of \u3ci\u3eAltica Subplicata\u3c/i\u3e (Coleoptera: Chrysomelidae) on Sand-Dune Willow
To investigate feeding patterns of a specialist herbivore, Altica subplicata, larvae and adults were caged separately on host plants, Salix cordata, and leaf damage was estimated. Young, relatively more pubescent leaves near the tops of the shoots were consumed more than older leaves. Larvae clearly preferred the young, pubescent leaves and avoided the oldest leaves. Adults showed a stronger preference for the first five young leaves, but amount of consumption did not differ among the older leaves.
Attachment ability on smooth and pubescent leaves was examined as a possible factor influencing feeding patterns. Scanning electron microscopy of tarsal adhesive structures and leaf surfaces was conducted to investigate how A. subplicata attaches to its host. Adhesive setae on the tarsi of adults may be effective for attachment on the older, smooth leaves and their tarsal claws are likely used to cling to trichomes of pubescent leaves. Larvae have fleshy adhesive pads for attachment. Laboratory experiments on attachment of larvae and adults to smooth and pubescent leaves under various wind conditions showed that wind caused difficulty in attachment and movement, but leaf pubescence did not affect the number of beetles that fell off leaves. However, larvae fell off more quickly when placed on pubescent leaves. Thus, other factors such as nutritional quality and microclimate provided by trichomes may be responsible for the preference for pubescent leaves exhibited by A. subplicata
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Bicontinuous Materials from Telechelic Macromonomers Using Thiol-ene Chemistry
Bicontinuous structures are beneficial to many applications from health and medicine to energy and the environment. Although these materials can be used for many applications, current strategies yield bicontinuous structures only under highly specific processing conditions. Development of a versatile platform to reliably obtain bicontinuous morphologies will be broadly beneficial. This work presents two platforms that can be used to produce bicontinuous morphologies using a simple Mitsunobu/thiol-ene strategy. This platform allows for the incorporation of a variety of polymer chemistries to yield well-defined polymer networks or multiblock copolymers (MBCs). It also allows for the systematic investigation of factors affecting the morphology such as the molecular weight between cross-links and the volume fraction of the network components. The ease at which these variables can be systematically investigated allows for rigorous fundamental studies of these composite systems.
In the first co-network system, the platform’s ability to tailor mechanical properties while maintaining good ion conductivity was demonstrated by comparing PEG-PDMS co-networks to PEG networks using EIS and DMA. Also, the effect of salt loading on thermal properties was explored using DSC. The second system, PEG-PS co-networks, demonstrated that varying the molecular weight of the precursor polymers results in control over d-spacing that fits well to de Gennes’s prediction (d ~ Mn0.5). Despite the variation in d-spacing, 22 - 55 nm, the ion conductivity and mechanical properties remained relatively consistent, demonstrating versatility in this system. Critical percolation thresholds were investigated by using ion conductivity and storage modulus to probe the continuity of the PEG and PS phases, respectively. Percolation theory suggests this system has a wide bicontinuous compositional window from fPEG = 0.225 -0.675. A preliminary phase diagram was generated by combining results from the molecular weight and volume fraction series. Finally, a simple synthesis for (MBCs) is demonstrated using the same Mitsunobu/thiol-ene platform. MBCs with ~4 blocks and two or three types of macromonomers were synthesized. Disordered phase separation was shown by SAXS and AFM. The versatile Mitsunobu/thiol-ene platform is easily able to synthesize different architectures using a range of polymer chemistries for various morphology and property studies
Capitalizing on a Captive Audience: A Collaborative Workshop Connecting Graduate Students to Open Access
The complexities of Open Access can result in uninformed high-stakes decision-making for researchers on the cusp of entering the publishing world. Graduate students need to understand how Open Access influences their research practices, and how to negotiate rights in a complex publishing ecosystem. Here we describe a collaboration between research librarians and writing center professionals that integrates Open Access education into a workshop series on graduate student writing. Specifically, we co-designed a presentation that bridged manuscript preparation (an obvious publication step) with the less-obvious issues surrounding Open Access
Work readiness in graduate recruitment and selection : a review of current assessment methods
Graduate recruitment and selection differs from other contexts in that graduate applicants generally lack job-related experience. Recent research has highlighted that employers are placing increasing value on graduates being work ready. Work readiness is believed to be indicative of graduate potential in terms of long term job performance and career advancement. A review of the literature has found that current graduate recruitment and selection practices lack the rigour and construct validity to effectively assess work readiness. In addition, the variety of interchangeable terms and definitions articulated by employers and academics on what constitutes work readiness suggests the need to further refine this construct. This paper argues that work readiness is an important selection criterion, and should be examined systematically in the graduate assessment process, as a construct in itself. The ineffectiveness of current assessment methods in being able to measure work readiness supports the need to develop a specific measure of work readiness that will allow more effective decision practices and potentially predict long term job capacity and performance.<br /
Capital Grant Funding : A Research Report
In May 2015 the Clothworkers' Foundation commissioned new research on the current provision of capital grant funding to the voluntary sector, with the particular aim of informing the Foundation's five-yearly strategy review. This report has been compiled to make the detailed findings of the study more widely available. It provides a comprehensive picture of the current scale and scope of capital grant funding by independent charitable foundations, and the perspectives of funders, applicants and grantees on emerging trends and issues.The research was carried out in association with the Centre for Giving and Philanthropy, Cass Business School and the Association of Charitable Foundations, and conducted by Cathy Pharoah, Catherine Walker and Richard Jenkins
Web-based museum trails on PDAs for university-level design students: Design and evaluation
This article, published in an international peer-reviewed journal, details the design and evaluation of trails at the Victoria & Albert Museum created for university students in design by curators and tutors from the Royal College of Art, University of Brighton, and the Royal Institute of British Architects. The trails were innovative in that they were not didactic but dialogic, containing and encouraging multiple perspectives, exploring social uses of museum spaces and non-traditional interpretations of museum artefacts. They succeeded in enhancing students’ knowledge of, interest in, and closeness to the artefacts.
Related outcomes included the trails themselves, a detailed summative evaluation report, a conference paper presented at a mobile learning symposium in London, and continuing collaborations with the Victoria & Albert Museum. The methodology for analysis was developed in the author's PhD research, which was conducted in parallel. The article has been cited in the British Journal of Educational Technology; Computers and Education; Interactive Learning Environments; Journal of Educational Computing Research; and in a doctoral thesis: Ken-Zen Chen (2012) Hidden Works in a Project of Closing Digital Inequalities: A Qualitative Inquiry in a Remote School (University of Illinois at Urbana-Champaign).
Broader findings suggest that technology has a key role to play in helping to maintain the museum as a learning space that complements that of universities as well as schools. The trails were analysed using a conceptual model the author created, which combined a contextual model of learning with activity theory. This complemented the more traditional method of front-end/ formative/ summative evaluation normally undertaken by museums. The model enabled differentiation of the personal, social and physical contexts of learning, and focused on the technology as mediating the students' learning. Walker formulated the theoretical framework for evaluating the project; he also undertook the summative evaluation of the research featured within this
Electrical Characteristics of Nanocrystalline Silicon Resistive Memory Devices
Resistive memory devices have been studied and fabricated using a wide variety of materials including chalcogenides [1], metal oxides [2], and hydrogenated amorphous silicon (a-Si:H) [3]. The most promising materials seem to be amorphous in nature, with the properties of the atomic lattices being conducive to the physical mechanisms that underlie the subsequent resistive switching. The devices are also finding applications beyond high-density digital memory, such as for electronic synapses in neuromorphic systems [4], [5]. However, a different set of properties is required in the latter case compared to devices that must only store binary values. In addition, it is well known that biological synapses are extremely unreliable and noisy, and yet the brain is still able to perform high-level cognitive functions [6]-[8]. This work uses pulse-based electrical characterization techniques to demonstrate the stochastic nature of resistive switching in nanocrystalline silicon (nc-Si) Conductive Bridge Resistive Memory (CBRAM) Devices. We chose nc-Si active layers so these devices could potentially be co-fabricated in the same process as nc-Si TFTs [9]-[11]. Our subsequent findings indicate the device properties may be particularly useful for some non-von Neumann computing paradigms. Though much research has been done using a-Si:H, results from nc-Si CBRAM devices have not been published. In this study, we showed that the switching of the device depends on the history of current passing though it, and not only the voltage applied. Further, the resistance switching in the devices is stochastic, making them ideal candidates for a biologically realistic synapse
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