98 research outputs found
Stable Isotope Turnover and Half-Life in Animal Tissues: A Literature Synthesis
No full textabstract: Stable isotopes of carbon, nitrogen, and sulfur are used as ecological tracers for a variety of applications, such as studies of animal migrations, energy sources, and food web pathways. Yet uncertainty relating to the time period integrated by isotopic measurement of animal tissues can confound the interpretation of isotopic data. There have been a large number of experimental isotopic diet shift studies aimed at quantifying animal tissue isotopic turnover rate λ (%·day[superscript -1], often expressed as isotopic half-life, ln(2)/λ, days). Yet no studies have evaluated or summarized the many individual half-life estimates in an effort to both seek broad-scale patterns and characterize the degree of variability. Here, we collect previously published half-life estimates, examine how half-life is related to body size, and test for tissue- and taxa-varying allometric relationships. Half-life generally increases with animal body mass, and is longer in muscle and blood compared to plasma and internal organs. Half-life was longest in ecotherms, followed by mammals, and finally birds. For ectotherms, different taxa-tissue combinations had similar allometric slopes that generally matched predictions of metabolic theory. Half-life for ectotherms can be approximated as: ln (half-life) = 0.22*ln (body mass) + group-specific intercept; n = 261, p<0.0001, r[superscript 2] = 0.63. For endothermic groups, relationships with body mass were weak and model slopes and intercepts were heterogeneous. While isotopic half-life can be approximated using simple allometric relationships for some taxa and tissue types, there is also a high degree of unexplained variation in our models. Our study highlights several strong and general patterns, though accurate prediction of isotopic half-life from readily available variables such as animal body mass remains elusive.The article is published at http://journals.plos.org/plosone/article?id=10.1371/journal.pone.011618
A case study in the evaluation of English training courses using a version of the CIPP model as an evaluative tool
No full textThis thesis presents an evaluative case study of the 20 English training courses offered in the Applied English Department (AED) of an Institute, given the pseudonym W.G, in southern Taiwan. No evaluation had been done since the AED had been set up and using Stufflebeam’s CIPP (Context, Input, Process and Product) evaluation model this research was carried out. The purpose of the research was to attempt, through the gathering of qualitative data from a variety of sources and using a variety of research instruments, an evaluation of the 20 English training courses which were designed for and taken by students who hoped, mainly, to become children's English language teachers. The courses were examined through four key components, namely, "course aims and objectives", "course contents and materials", "course conduct and teaching-learning process" and "assessment and student performance". Data were gathered through questionnaires, interviews and the review of existing documents and was obtained from current students, directors of the AED, instructors, alumni and employers of alumni. The resultant data served to present a comprehensive overview of the AED and the 20 English training courses and furnished evidence sufficient to allow for a number of recommendations for improvement and change to emerge. Fundamentally it is not clear that there is sufficient congruence of students needs and the courses offered. It emerged that the AED would probably benefit from a refocusing of student needs, a review of AED structures and governance, uniform syllabus design and presentation, a review of student feedback on instructor performance and a number of fundamental adjustments to the courses, in particular, their content, teaching methodology and assessment. Overall the AED had many positive aspects all of which could be built on and added to as the results of the data suggested. It emerged that the CIPP evaluation model has, in the educational context, a lot to commend it and this has been illustrated in this research. If followed carefully it covers all aspects and features of a program and provides a methodical, all-embracing design which can produce useful material for exploration and adoption if appropriate. It is in most cases a positive program enhancing exercise designed to develop rather than close existing programs
Optimizing Contractor Organizational Agility in Dynamic Markets
No full textabstract: Over the last twenty years, governments at all levels have made changes to increase their level of accountability and transparency. The researcher proposed that the concepts of organizational agility (OA) (leveraging core competencies, proactively seeking new opportunities, implementation of performance metrics, and strategically planning projects) are well-aligned with the public accountability systems. In the first part of this dissertation, the researcher examined the components of a “Value-Based Model” for public works contractor selection and project delivery, and its propensity to increase public accountability. The researcher studied 415 projects ($561.47M value) delivered with the Value-Based Model at eight different public agencies over a ten-year period.
Next, the researcher analyzed factors affecting contractor organizational agility. In light of the “Great Recession”, the concepts of organizational agility offers insights into companies could have made different strategic decisions to avoid many of the issues faced. Construction was particularly affected: by January 2010, unemployment reached approximately 20 percent. One way to combat declining profits is to adjust general overhead costs (indirect expenses). These costs include items such as home office expenses, business development, and bonuses. The objective of the second part of this research was to conduct a study of how contractors responded to dynamic market conditions and to identify if whether contractors’ company attributes impacted their responses to the market changes. A total of 437 contractors responded to the survey, and 92 percent reported that they reduced overhead costs in five areas, by an average of about 15 percent. Additional analysis suggests that there are distinct categories of overhead flexibility.Dissertation/ThesisDoctoral Dissertation Construction 201
Does prominent coastal upwelling along New Jersey lead to increases in offshore wind turbine power production?
No full textLarge offshore wind turbines are planned for construction off the New Jersey coastline to aid in the state's transition towards more renewable energy and decrease their dependence on fossil fuels. To facilitate this transition, it is important to have accurate estimates of how much power these turbines will generate. From an oceanographic perspective, New Jersey is a relatively unique wind farm location in that it frequently experiences the phenomenon known as coastal upwelling. Upwelling, which brings colder water from depth to the surface, is a result of persistent southwesterly winds along New Jersey’s coastline in the summer months. Coastal upwelling can occur along any coast with an alongshore wind, however large temperature shifts (2 to 3 °C) are a defining characteristic of upwelling in the Mid-Atlantic Bight due to the presence of the subsurface cold pool.
To investigate the effects of upwelling, wind speed data at various altitudes from a floating LiDAR buoy (Atlantic Shores Offshore Wind Buoy 4) were examined across the upwelling season to understand the atmospheric and oceanic conditions within the Atlantic Shores Offshore Wind Lease Area. Daily images of sea surface temperature from the AVHRR satellite were used to determine which days in the chosen timeframe experienced large sea surface temperature shifts associated with coastal upwelling. In total, this methodology yielded a total of 39 upwelling days (43.8%) and 50 non-upwelling days (56.2%).
To investigate the relationship between upwelling and power generation, this study compared the power production estimates between the upwelling and non-upwelling days. Power estimates were made using the power curve for a 15 MW wind turbine. The results of the independent sample t-tests revealed that wind speeds and power production estimations were significantly greater at all times of day during upwelling conditions (P < 0.05 for all comparisons).
There is a need to examine the effects of the oceanic conditions on wind characteristics because the ocean and atmosphere interact dynamically. The results of this analysis are novel in the aspect that few (if any) studies have looked at the effects of upwelling on wind characteristics in the context of power generation.M.S.Includes bibliographical reference
A case study of a policy decision: anonymous marking with special reference to the university of Durham in 1994
No full textBroken down into four separate Chapters, this thesis presents a study of anonymous marking, with special reference to the experience of the University of Durham which introduced a policy of anonymous marking in 1994. It is a study of a single university, and of a very recent change. The thesis adopts a range of different approaches. Chapter One identifies the principles underlying anonymous marking and examines them in the context of the mission, aims and objectives of a university. Chapter Two reviews the literature which has sought various explanations for women achieving a lower proportion of first and third class degrees compared to men, suggesting that more attention should be paid to investigating the differential performance of men and women in individual subjects rather than for degrees as a whole; the pattern of results in the one not being the same as the pattern of results in the other. The hypothesis that sex bias in marking lies behind this pattern is shown to be inconclusive. As a result, the positions of a number of high profile individuals and educational organisations, which advocate the widespread introduction of anonymous marking based on the fact that sex bias in marking has been proven to exist, are shown to be misplaced and possibly premature. In Chapter Three, the practical operation of a newly implemented system of anonymous marking, and the processes involved in the run up to, and after, the policy decision to introduce the system at the University of Durham, are viewed in a case study. The university is analysed as a political system in which the policy process is understood by identifying the different interests involved. The practical implications - in terms of costs, time, administration, anonymity and morale - for all members of the university are considered against the criteria for anonymous marking, and the aims and objectives of the university. In the concluding Chapter it is recommended that higher education institutions contemplating introducing anonymous marking take a close look at the practicability and desirability of such a system, particularly in the light of other developments in higher education, and the feelings of some of the academic staff and of the student community who did not like to feel anonymous. If a system of anonymous assessment is to be introduced it should be done carefully, with wide consultation and with a clear view as to what the system is being designed to achieve, heeding the lessons and the practical recommendations of this study. Otherwise good objectives will be poorly served by poor policy changes
Fantastic alterities and The Sandman
No full textThis article explores the ways in which the comics medium enhances our understanding of literary models of the Fantastic. It examines the presence and depiction of multiple worlds in Neil Gaiman’s The Sandman, with specific reference to the role of the comics medium and its denial of mimesis when creating such alterities.
It initially uses literature review to establish a contemporary working model of the Fantastic, taking as its basis the framework devised by Tzvetan Todorov, and incorporating the later work of Rosemary Jackson, A B Chanady, and Christine Brooke-Rose. It establishes the position of the Fantastic as a literary mode lying between the marvellous (supernatural accepted) and the uncanny (supernatural explained), and clarifies the distinction between the mode of the Fantastic (which encompasses various genres) and the genre itself.
The article then considers the ways in which both the form and content of the comics medium sustain the mode of the fantastic. It broadly discusses the ways in which the following factors contribute to this process:
• subject matter: fantastic events, super powers, alternate worlds
• non-realistic aesthetic: pop art, stylised visuals, fiction of fonts (invoking the tension between hand-drawn and computerised artwork or lettering)
• authorial reticence: the possibilities for surpassing or discarding narrative voice
• the role of the reader: as both interpreter and co-creator.
It then focuses more closely upon the genre of the Fantastic, establishing the ways in which this genre is opposed to both magical realism (outright fantasy) and realism (where such events are explained). It summarises the role of various qualities of the Fantastic in this regard, which include an antinomy between the natural and supernatural, author reticence, over- or under-determined language, and a defiance of absolute meaning in favour of interpretation or hesitation .
The article then proceeds to two case studies, taken from Neil Gaiman’s The Sandman: A Game of You and The Kindly Ones. The first analyses the construction of two contrasting alterities (‘The Land’ and ‘New York’) and examines the ways in which, despite initial appearances, these two worlds are both equally removed from the referent of ‘reality’. It proceeds to discuss the use made of over- and under-determined signifiers, the transformation motif, intertextuality, and the redefinition of static notions (home, gender) as fluid and undefined. It deconstructs The Kindly Ones in similar terms, considering the ways in which its triple alterities are all simultaneously validated by the text and the role of motifs such as multiple names and duplicated characters.
It concludes that, like the Fantastic, the comics medium exposes the notion of ‘reality’ as a constructed referent, which the text’s alterities comment on. The nature of the medium allows for the construction and sustenance of multiple worlds without recourse to a stable notion of reality. As the reader’s hesitation destabilises interpretation of reality versus fantasy, absolute meaning is denied. It therefore seems that comics offer what might be best described as a postmodern vision of the Fantastic
Author Correction: Comprehensive analysis of chromothripsis in 2,658 human cancers using whole-genome sequencing
No full textauthor correctio
Groundwater residence time estimates obscured by anthropogenic carbonate
No full text© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Seltzer, A. M., Bekaert, D. V., Barry, P. H., Durkin, K. E., Mace, E. K., Aalseth, C. E., Zappala, J. C., Mueller, P., Jurgens, B., & Kulongoski, J. T. Groundwater residence time estimates obscured by anthropogenic carbonate. Science Advances, 7(17), (2021): eabf3503, https://doi.org/10.1126/sciadv.abf3503.Groundwater is an important source of drinking and irrigation water. Dating groundwater informs its vulnerability to contamination and aids in calibrating flow models. Here, we report measurements of multiple age tracers (14C, 3H, 39Ar, and 85Kr) and parameters relevant to dissolved inorganic carbon (DIC) from 17 wells in California’s San Joaquin Valley (SJV), an agricultural region that is heavily reliant on groundwater. We find evidence for a major mid-20th century shift in groundwater DIC input from mostly closed- to mostly open-system carbonate dissolution, which we suggest is driven by input of anthropogenic carbonate soil amendments. Crucially, enhanced open-system dissolution, in which DIC equilibrates with soil CO2, fundamentally affects the initial 14C activity of recently recharged groundwater. Conventional 14C dating of deeper SJV groundwater, assuming an open system, substantially overestimates residence time and thereby underestimates susceptibility to modern contamination. Because carbonate soil amendments are ubiquitous, other groundwater-reliant agricultural regions may be similarly affected.his work was conducted as a part of the USGS National Water Quality Assessment Program (NAWQA) Enhanced Trends Project (https://water.usgs.gov/nawqa/studies/gwtrends/). Measurements at Argonne National Laboratory were supported by Department of Energy, Office of Science under contract DE-AC02-06CH11357. Measurements at Pacific Northwest National Laboratory were part of the Ultra-Sensitive Nuclear Measurements Initiative conducted under the Laboratory Directed Research and Development Program. PNNL is operated by Battelle for the U.S. Department of Energy under Contract DE-AC05-76RL01830. This work was also partially supported by NSF award OCE-1923915 (to A.M.S. and P.H.B. at WHOI)
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