977 resultados para California, USA
Resumo:
Agricultural soils emit about 50% of the global flux of N2O attributable to human influence, mostly in response to nitrogen fertilizer use. Recent evidence that the relationship between N2O fluxes and N-fertilizer additions to cereal maize are non-linear provides an opportunity to estimate regional N2O fluxes based on estimates of N application rates rather than as a simple percentage of N inputs as used by the Intergovernmental Panel on Climate Change (IPCC). We combined a simple empirical model of N2O production with the SOCRATES soil carbon dynamics model to estimate N2O and other sources of Global Warming Potential (GWP) from cereal maize across 19,000 cropland polygons in the North Central Region (NCR) of the US over the period 1964–2005. Results indicate that the loading of greenhouse gases to the atmosphere from cereal maize production in the NCR was 1.7 Gt CO2e, with an average 268 t CO2e produced per tonne of grain. From 1970 until 2005, GHG emissions per unit product declined on average by 2.8 t CO2e ha−1 annum−1, coinciding with a stabilisation in N application rate and consistent increases in grain yield from the mid-1970’s. Nitrous oxide production from N fertilizer inputs represented 59% of these emissions, soil C decline (0–30 cm) represented 11% of total emissions, with the remaining 30% (517 Mt) from the combustion of fuel associated with farm operations. Of the 126 Mt of N fertilizer applied to cereal maize from 1964 to 2005, we estimate that 2.2 Mt N was emitted as N2O when using a non-linear response model, equivalent to 1.75% of the applied N.
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This publication is the first in a series of scholarly reports on research-based practice related to the First Year Experience in Higher Education. This report synthesises evidence about practice-based initiatives and pragmatic approaches in Aotearoa (New Zealand) and Australia that aim to enhance the experience of commencing students in the higher education sector. Trends in policies, programs and practices ... examines the first year experience literature from 2000-2010. It acknowledges the uniqueness of the Australasian socio-political context and its influence on the interests and output of researchers. The review surveyed almost 400 empirical reports and conceptual discussions produced over the decade that dealt with the stakeholders, institutions and the higher education sector in Australasia. The literature is examined through two theoretical constructs or “lenses”: first, a set of first year curriculum design principles and second, the generational approach to describing the maturation of initiatives. These outcomes and suggested directions for further research provide the challenges and the opportunities for FYE adherents, both scholars and practitioners, to grapple with in the next decade.
Using cost-effective multimedia to create engaging learning experiences in law and other disciplines
Resumo:
This is the final report of an Australian Learning and Teaching Council Teaching Fellowship which addressed the needs of two separate groups of learners: (1) final year law students studying ethics and (2) law academics and other interested educators in higher education wishing to use information and communication technologies (ICT) to create engaging learning environments for their students but lacking the capacity to do so. The Fellowship resulted in final year law students being infused with an improved appreciation of ethical practice than they receive from traditional lecture/tutorial means by the development of an integrated program of blended learning including an online program entitled "Entry into Valhalla". This "ethics capstone‟ utilises multimedia produced using cost effective resources (including the "Second Life" virtual environment) to create engaging, contextualised learning experiences. The Fellowship also constructed the knowledge of producing cost-effective multimedia projects in other law academics and other educators in higher education by staff development activities comprising workshops, conference presentations and an interactive website using the "Entry into Valhalla" program as a case study exemplar.
Resumo:
In the late twentieth and early twenty-first centuries, Australia’s relationship with its Asian neighbours has been the subject of ongoing aesthetic, cultural and political contestations. As Alison Richards has noted, Australia’s colonial legacy, its Asia-Pacific location, and its ‘white’ self-perception have always made Australia’s relations with Asia fraught. In the latter part of the twentieth century, the paradoxes inherent in Australia’s relationships with and within the Asian region became a dominant theme in debates about nation, nationhood and identity, and prompted a shift in the construction of ‘Asianness’ on Australian stages. On the one hand, anxiety about the multicultural policy of the 1970s and 1980s, and then Prime Minister Paul Keating’s push for greater economic, cultural and artistic exchange with Asia via policies such as the Creative Nation Cultural Policy (1994), saw large numbers of Australians latch on to the reactionary, racist politics of Pauline Hanson’s One Nation Party. As Jacqueline Lo has argued, in this period Asian-Australians were frequently represented as an unassimilable Other, a threat to Australia’s ‘white’ identity, and to individual Australians’ jobs and opportunities. On the other hand, during the same period, a desire to counter the racism in Australian culture, and develop a ‘voice’ that would distinguish Australian cultural products from European theatrical traditions, combined with the new opportunities for cross-cultural exchange that came with the Creative Nation Cultural Policy to produce what Helen Gilbert and Jacqueline Lo have characterised as an Asian turn in Australian theatre...
Resumo:
Separate systems of justice for children and young people have always been beset by issues of contradiction and compromise. There is compelling evidence that such ambiguity is currently being `resolved' by a greater governmental resort to neo-conservative punitive and correctional interventions and a neo-liberal responsibilizing mentality in which the protection historically afforded to children is rapidly dissolving. This resurgent authoritarianism appears all the more anachronistic when it is set against the widely held commitment to act within the guidelines established by various children's rights conventions. Of note is the United Nations Convention on the Rights of the Child, frequently described as the most ratified human rights convention in the world, but lamentably also the most violated. Based on international research on juvenile custody rates and children's rights compliance in the USA and Western Europe, this article examines why and to what extent `American exceptionalism' might be permeating European nation states.
Resumo:
Purpose: This study provides insight into the histories and current statuses of queer community archives in California and explores what the archives profession can learn from the queer community archives and archivists. Through the construction of histories of three community archives (GLBT Historical Society; Lavender Library, Archives, and Cultural Exchange of Sacramento, Inc.; and ONE National Gay & Lesbian Archives), the study discovered why these independent, community-based archives were created, the issues that influenced their evolution, and the similarities and differences among them. Additionally, it compared the community archives to institutional archives which collect queer materials to explore the similarities and differences among the archives and determine possible implications for the archives profession. Significance: The study contributes to the literature in several significant ways: it is the first in-depth comparative history of the queer community archives; it adds to the cross-disciplinary research in archives and history; it contributes to the current debates on the nature of the archives and the role of the professional archivist; and it has implications for changing archival practice. Methodology: This study used social constructionism for epistemological positioning and new social history theory for theoretical framework. Information was gathered through seven oral history interviews with community archivists and volunteers and from materials in the archives’ collections. This evidence was used to construct the histories of the archives and determine their current statuses. The institutional archives used in the comparisons are the: University of California, Berkeley’s Bancroft Library; University of California, Santa Cruz’s Special Collections and University Archives; and San Francisco Public Library’s James C. Hormel Gay and Lesbian Center. The collection policies, finding aids, and archival collections related to the queer communities at the institutional and community archives were compared to determine commonalities and differences among the archives. Findings: The findings revealed striking similarities in the histories of the community archives and important implications for the archives’ survival and their relevancy to the archives profession. Each archives was started by an individual or small group collecting materials to preserve history that would otherwise have been lost as institutional archives were not collecting queer materials. These private collections grew and became the basis for the community archives. The community archives differ in their staffing models, circulation policies, and descriptive practices. The community archives have grown to incorporate more public programming functions than most institutional archives. While in the past, the community archives had little connection to institutional archives, today they have varying degrees of partnerships. However, the historical lack of collecting queer materials by institutional archives makes some members of the communities reluctant to donate materials to institutional archives or collaborate with them. All three queer community archives are currently managed by professionally trained and educated archivists and face financial issues impacting their continued survival. The similarities and differences between the community and institutional archives include differences in collection policies, language differences in the finding aids, and differing levels of relationships between the archives. However, they share similar sensitivity in the use of language in describing the queer communities and overlap in the types of materials collected. Implications: This study supports previous research on community archives showing that communities take the preservation of history into their own hands when ignored by mainstream archives (Flinn, 2007; Flinn & Stevens, 2009; Nestle, 1990). Based on the study’s findings, institutional archivists could learn from their community archivist counterparts better ways to become involved in and relevant to the communities whose records they possess. This study also expands the understanding of history of the queer communities to include in-depth research into the archives which preserve and make available material for constructing history. Furthermore, this study supports reflective practice for archivists, especially in terms of descriptions used in finding aids. It also supports changes in graduate education for archives students to enable archivists in the United States to be more fully cognizant of community archives and able to engage in collaborative, international projects. Through this more activist role of the archivists, partnerships between the community and institutional archives would be built to establish more collaborative, respectful relationships with the communities in this post-custodial age of the archives (Stevens, Flinn, & Shepherd, 2010). Including community archives in discussions of archival practice and theory is one way of ensuring archives represent and serve a diversity of voices.
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The state of the practice in safety has advanced rapidly in recent years with the emergence of new tools and processes for improving selection of the most cost-effective safety countermeasures. However, many challenges prevent fair and objective comparisons of countermeasures applied across safety disciplines (e.g. engineering, emergency services, and behavioral measures). These countermeasures operate at different spatial scales, are funded often by different financial sources and agencies, and have associated costs and benefits that are difficult to estimate. This research proposes a methodology by which both behavioral and engineering safety investments are considered and compared in a specific local context. The methodology involves a multi-stage process that enables the analyst to select countermeasures that yield high benefits to costs, are targeted for a particular project, and that may involve costs and benefits that accrue over varying spatial and temporal scales. The methodology is illustrated using a case study from the Geary Boulevard Corridor in San Francisco, California. The case study illustrates that: 1) The methodology enables the identification and assessment of a wide range of safety investment types at the project level; 2) The nature of crash histories lend themselves to the selection of both behavioral and engineering investments, requiring cooperation across agencies; and 3) The results of the cost-benefit analysis are highly sensitive to cost and benefit assumptions, and thus listing and justification of all assumptions is required. It is recommended that a sensitivity analyses be conducted when there is large uncertainty surrounding cost and benefit assumptions.
Resumo:
Five basalt samples from the Point Sal ophiolite, California, were examined using HRTEM and AEM in order to compare observations with interpretations of XRD patterns and microprobe analyses. XRD data from ethylene-glycol-saturated samples indicate the following percentages of chlorite in mixed-layer chlorite-smectite identified for each specimen: (i) L2036 almost-equal-to 50%, (ii) L2035 almost-equal-to 70 and 20%, (iii) 1A-13 almost-equal-to 70%, (iv) 1B-42 almost-equal-to 70%, and (v) 1B-55 = 100%. Detailed electron microprobe analyses show that 'chlorite' analyses with high Si, K, Na and Ca contents are the result of interlayering with smectite-like layers. The Fe/(Fe + Mg) ratios of mixed-layer phyllosilicates from Point Sal samples are influenced by the bulk rock composition, not by the percentage of chlorite nor the structure of the phyllosilicate. Measurements of lattice-fringe images indicate that both smectite and chlorite layers are present in the Point Sal samples in abundances similar to those predicted with XRD techniques and that regular alternation of chlorite and smectite occurs at the unit-cell scale. Both 10- and 14-angstrom layers were recorded with HRTEM and interpreted to be smectite and chlorite, respectively. Regular alternation of chlorite and smectite (24-angstrom periodicity) occurs in upper lava samples L2036 and 1A-13, and lower lava sample 1B-42 for as many as seven alternations per crystallite with local layer mistakes. Sample L2035 shows disordered alternation of chlorite and smectite, with juxtaposition of smectite-like layers, suggesting that randomly interlayered chlorite (< 0.5)-smectite exists. Images of lower lava sample 1B-55 show predominantly 14-angstrom layers. Units of 24 angstrom tend to cluster in what may otherwise appear to be disordered mixtures, suggesting the existence of a corrensite end-member having thermodynamic significance.
Resumo:
Within the communicative space online Social Network Sites (SNS) afford, Niche Social Networks Sites (NSNS) have emerged around particular geographic, demographic or topic-based communities to provide what broader SNS do not: specified and targeted content for an engaged and interested community. Drawing on a research project developed at the Queensland University of Technology in conjunction with the Australian Smart Services Cooperative Research Centre that produced an NSNS based around Adventure Travel, this paper outlines the main drivers for community creation and sustainability within NSNS. The paper asks what factors motivate users to join and stay with these sites and what, if any, common patterns can be noted in their formation. It also outlines the main barriers to online participation and content creation in NSNS, and the similarities and differences in SNS and NSNS business models. Having built a community of 100 registered members, the staywild.com.au project was a living laboratory, enabling us to document the steps taken in producing a NSNS and cultivating and retaining active contributors. The paper incorporates observational analysis of user-generated content (UGC) and user profile submissions, statistical analysis of site usage, and findings from a survey of our membership pool in noting areas of success and of failure. In drawing on our project in this way we provide a template for future iterations of NSNS initiation and development across various other social settings: not only niche communities, but also the media and advertising with which they engage and interact. Positioned within the context of online user participation and UGC research, our paper concludes with a discussion of the ways in which the tools afforded by NSNS extend earlier understandings of online ‘communities of interest’. It also outlines the relevance of our research to larger questions about the diversity of the social media ecology.
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Understanding the link between tectonic-driven extensional faulting and volcanism is crucial from a hazard perspective in active volcanic environments, while ancient volcanic successions provide records on how volcanic eruption styles, compositions, magnitudes and frequencies can change in response to extension timing, distribution and intensity. Significantly, incorrect tectonic interpretations can be made when the spatial-temporal-compositional trends of, and source contributions to magmatism are not properly considered. This study draws on intimate relationships of volcanism and extension preserved in the Sierra Madre Occidental (SMO) and Gulf of California (GoC) regions of western Mexico. Here, a major Oligocene rhyolitic ignimbrite “flare-up” (>300,000 km3) switched to a dominantly bimodal and mixed effusive-explosive volcanic phase in the Early Miocene (~100,000 km3), associated with distributed extension and opening of numerous grabens. Rhyolitic dome fields were emplaced along graben edges and at intersections of cross-graben and graben-parallel structures during early stages of graben development. Concomitant with this change in rhyolite eruption style was a change in crustal source as revealed by zircon chronochemistry with rapid rates of rhyolite magma generation due to remelting of mid- to upper crustal, highly differentiated igneous rocks emplaced during earlier SMO magmatism. Extension became more focused ~18 Ma resulting in volcanic activity being localised along the site of GoC opening. This localised volcanism (known as the Comondú “arc”) was dominantly effusive and andesite-dacite in composition. This compositional change resulted from increased mixing of basaltic and rhyolitic magmas rather than fluid flux melting of the mantle wedge above the subducting Guadalupe Plate. A poor understanding of space-time relationships of volcanism and extension has thus led to incorrect past tectonic interpretations of Comondú-age volcanism.
Resumo:
Cenozoic extension in western Mexico has been divided into two episodes separated by the change from convergence to oblique divergence at the plate boundary. The Gulf Extensional Province is thought to have started once subduction ended at ~12.5 Ma whereas early extension is classified as Basin and Range. Mid-Miocene volcanism of the Comondú group has been considered as a subduction-related arc, whereas post ~12.5 Ma volcanism would be extension-related. Our new integration of the continental onshore and offshore geology of the south-east Gulf region, backed by tens of Ar-Ar and U-Pb ages and geochemical studies, document an early-mid Miocene rifting and extension-related bimodal to andesitic magmatism prior to subduction termination. Between ~21 and 11 Ma a system of NNW-SSE high-angle extensional faults rifted the western side of the Sierra Madre Occidental (SMO) ignimbrite plateau. In Nayarit, rhyolitic domes and some basalts were emplaced along this extensional belt at 18-17 Ma. These rocks show strong antecrystic inheritance but an absence of Mesozoic and older xenocrysts, suggesting a genesis in the mid-upper crust triggered by extension-induced basaltic influx. In Sinaloa, large grabens were floored by huge dome complexes at ~21-17 Ma and filled by continental sediments with interlayered basalts dated at 15 Ma. Mid-Miocene volcanism, including the largely volcaniclastic Comondú strata in Baja California, was thus emplaced in rift basins and appears associated to decompression melting rather than subduction. Along the coast, flat-lying basaltic lava flows dated at 11-10 Ma are exposed just above the present sea level. Here crustal thickness is 25-20 Km, almost half that in the core of the SMO, implying significant lithosphere stretching before ~11 Ma. This mafic pulse, with relatively high Ti but still clear Nb-Ta negative spikes, may be related to the detachment of the lower part of the subducted slab, allowing asthenosphere to flow into parts of the mantle previously fluxed by subduction fluids. Very uniform OIB-like lavas appear in late Pliocene and Pleistocene, only 18 m.y. after the onset of rifting and ~9 m.y. after the end of subduction. Our study shows that rifting began much earlier than Late Miocene and progressively overwhelmed subduction in generating magmatism.