2,718 research outputs found

    Researching New Visual Art in the 21st Century

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    poster abstractMy poster presentation represents several projects I have undertaken that examine and analyze trends in visual art in the twenty-first century: One ongoing project represented in the poster session concerns work I do as the Advisory Editor for Contemporary Art for Grove Art Online (GAO), a compendium of current art historical scholarship covering world art from all periods, published online by Oxford University Press. As Advisory Editor I conceptualize, commission, and provide editorial oversight for 1-2 updates each year of 12-20 articles written around particular themes. For example, a 2011 update of 15 articles produced under my editorial supervision, titled “Visual Culture,” featured the emergence of visual culture as an interdisciplinary field of study that analyzes current issues and concepts in public art, new communication technologies, consumer culture, and globalization, among other arenas of culture. Besides serving as editor, I wrote one of the articles for the Visual Culture update, on the French installation artist Christian Boltanski. A second project represented in the poster session is a book titled Themes of Contemporary Art: Visual Art after 1980, first published by Oxford University Press in 2005. My co-author Craig McDaniel and I have found that we need to keep updating the book because so much significant new art is being made in the twenty-first century. Artists keep challenging the paradigms and definitions of art with unusual materials, locations, content, and purposes. For example, in the second edition of the book, published in 2010, we added a new chapter on the theme of science in contemporary art, analyzing why and how many artists today are responding to discoveries and methodologies drawn from the sciences, especially the life science. The third edition, forthcoming in 2012, adds a new chapter on the theme of memory, looking at such topics as the role of public memorials in the contemporary world, and the influence of digital information flow and digital archives on the operations of personal and collective memory. My research area—new art being made in the twenty-first century—poses a special challenge because “the tap is always open” regarding the objects I want to analyze. Artists keep making more art, and continue to push art in new directions. I am deeply grateful for the grant funding the university has provided, which has helped me at least attempt to keep up with the constant flood of new developments by traveling to study significant contemporary art projects first-hand. Some of my research as an editor and author for Grove Art Online has been supported by the IUPUI Arts and Humanities Initiative. Research for my book, Themes of Contemporary Art, has been supported by an IU New Frontiers in the Arts and Humanities grant

    The autonomic innervation of smooth muscle

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    This item was digitized by the Internet Archive. Thesis (M.A.)--Boston UniversityA thesis reviewing the recent work concerning the autonomic innervation of smooth muscle cells has been prepared, and without the support of individual investigations by the author a few conclusions have been proposed. The nature of the gross anatomy of the autonomic nervous system is well-known, and is not discussed in the paper. The function of the autonomic system is "briefly described as the "maintenance of stability or homeostasis in the fluid matrix of the organism." (Cannon and Rosenblueth, 1937) There are found in the literature two theories which deal with the nature of smooth muscle cells. The work of McGill (1907, 1909) and Tiegs (1924) was presented as evidence for the action of neurofibrillae in contraction. Observations of McGill (1907, 1909), Evans (1926), Bozler (1938, 1939) and others indicated that the smooth musculature of the viscera, and particularly that of the uterus, is syncytial, and that conduction from muscle cell to muscle cell takes place directly through interprotoplasmic bridges. Fulton and Lutz (1942) have described a vascular smooth muscle syncytium, discontinuous at the junctions of the vessels, in the retrolingual membrane of the frog. On the other hand, the work of Tiegs (1924), Eccles and Magladery (1937b) and Cannon and Rosenblueth (1937) showed that in certain areas of the smooth musculature, particularly in the nictitating membrane, there is no evidence for the presence of a syncytium. In this case the transfer of impulses from cell to cell is probably humoral. It may be concluded that there are two types of smooth muscle, one syncytial and the other consisting of independent cells, and that these occur in characteristic regions of the body. The various mechanisms for the contraction of capillaries are also discussed in the literature. Clark and Clark (1925b, 1940), Florey and Carleton (1925), Michels (1935) and Zweifach (1934, 1937) have found no evidence for the dependence of the capillaries on the Rouget cells (pericytes, pericapillary cells) for contraction; on the other hand, Vimtrup (1922), Bensley and Vimtrup (1920), Jones (1935), and Fulton and Lutz (1940, 1941, 1942) presented experiments on living tissue and observations on fixed preparations as evidence for the contractility of certain pericapillary cells (the Rouget cells). Zweifach (1937) suggested a classification of the capillaries based on the structure of their walls. Thus he described arterio-venous bridges, which are muscular and actively contractile, and true capillaries, which are endothelial, and do not possess muscular perivascular elements. In connection with the distribution of smooth muscle cells in the body, the papers of Ingalls (1933), Macklin (1929) and Acheson (1938) were outlined. Ingalls described the embryology and the anatomy of the dilator and the sphincter muscles of the iris; Macklin classified the pulmonary musculature as bronchial and interstitial, and defined the limits of both; and Acheson stated that the musculature of the nictitating membrane does not extend to its outer limit but only to its origin. The differences in the physiology of smooth muscle from that of striated muscle were discussed briefly, and the work of Ferguson (1940) on the nerve-free smooth muscle of the chick amnion was presented here. There are three broad theories concerning the morphological relations between smooth muscle cell and nerve fiber, and the monograph by Boeke (1940) describes them briefly. The first theory states that the postganglionic fibers go directly and independently to innervate the effector cells. The second theory says that the interstitial cells of Cajal intervene between the postganglionic fiber and the effector; and the third theory describes a gradual transition from a neuro-fibrillar network into a terminal reticulum which is apparently present everywhere in the body. The work of many authors in relation to these theories was presented, and it would appear that the real nature of the autonomic innervation of smooth muscle may involve a combination of these three theories. Thus it appears that the postganglionic fibers are in contact with Cajal's interstitial cells, which are syncytial in nature, and that the fibers of these cells are in contact with, and may form, a delicate terminal reticulum of nerve fibers throughout the body. Regional descriptions of the innervation of the smooth muscle of the various systems of the body were given. In the vascular musculature, Larsell (1921, 1922), J. D. Boyd (1937, 1941) and others describe endings on the muscle cells of arteries and arterioles; Michels (1935, 1936) and Larsell and Dow (1933) were unable to find endings on either the endothelium or the pericytes of capillaries, though many have shown that these smaller vessels are accompanied by nerves. Boeke (1932) reported that in the vessels of the human eye the nerve fibers extended to the muscle cells and continued into an extremely delicate network within them. In the urogenital musculature, the work of Gruber (1938), Stewart (1937), Kleyntjens and Langworthy (1937), Langworthy and Murphy (1939), Davis (1933) and others was outlined. Ho nerve endings were found in the ureter or the uterus, but were demonstrated in the bladder and the fallopian tube. Nerve endings in the gut musculature were found by Carpenter (1918), Hill (1927), Irwin (1931) and Li (1940). The plexuses in the walls of the gastrointestinal tract were described by Langley (1921), Hill (1927), van Esveld (1923), Schabadasch (1930), Irwin (1931), McSwiney (1931) and Li (1940). These plexuses, while independent, are connected to the vagus and sympathetic fibers. The majority of these authors also indicate that the interstitial cells of Cajal are to be considered as the end-point of the enteric system. Plexuses around the sphincter and dilator muscles of the iris were described by Boeke (1933), Jones (1932) and S. L. Clark (1937), and endings on or in the cells of these muscles were also described. The work of Larsell (1921, 1922), Larsell and Mason (1921), Larsell and Dow (1933) and Macklin (1929) defined plexuses in the respiratory musculature; nerve terminations are also described. Cannon and Eosenblueth (1937), in dealing with the physiology of the autonomic neuro-effector system, describe the dual innervation of the smooth musculature from neurons of both the sympathetic and parasympathetic systems, and repeat the well-known fact that this innervation is antagonistic. The theories of chemical mediation are discussed; these lead to the belief that autonomic impulses are transmitted from neuron to neuron and from neuron to plain muscle fiber by the intervention of either acetylcholine or an adrenalinlike substance, sympathin. Also, there are apparently two sympathins, an inhibitory one and an excitatory one. The significance of the relative stability of sympathin and the rapid destruction of acetylcholine in the function of the sympathetic and the parasympathetic systems is discussed. Also mentioned is the theory of electrical transmission of impulses; this postulates that the electrical changes produced during conduction in the nerve serve in the transmission of the impulse across the synapse. It is probable that both mechanisms are involved, and that when the electrical impulse fails to reach adjacent nerve or muscle cells the chemical mediator may intervene to complete the transmission. The steps in the transmission of impulses from neuron to muscle fiber are outlined briefly, and the action of various drugs in blocking this transmission is described. The experiments on denervation are also discussed; these indicate that the severing of the nerve supply to the effector increases its response to mechanical stimulation and may decrease its response to electrical and chemical stimulation. In criticizing the discrepancies in the results on the morphology of autonomic innervation of smooth muscles, the variation, in staining techniques, together with the results obtained with silver and with methylene blue techniques, is discussed. It is concluded that the work on this problem is by no means finished, and that consistent results can be produced moat reliably with similar methods

    The Merit of Intensive Leadership Development Programs on Building-Level Administrators\u27 Sustainability

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    With recent research identifying the propensity and ability of principals to lead as a key culprit of school and district failure, it would seem that one of the most reasonable steps should be to better determine how effective specially designed leadership development programs in the area of educational leadership are at not only equipping principals and school-based leaders, but at creating a foundation and a prevailing culture for longevity or sustainability in those positions. If the development of principals and other school-based leaders is vital to the improvement of schools, the effectiveness of the measures implemented to bring about that improvement has to be examined. Whether those measures are designed with the purpose of increasing leadership capacity via the retention or sustainability of principals, which could result in a positive effect on the achievement of students or by reforming systems of recruitment and induction within the organization, a greater effort is needed to keep effective principals in those positions where increased student outcomes are manifested

    The Impact of Using Social Media for Advertising Appliances on Consumer Behaviour

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    The small appliance industry in South Africa offers consumers a wide range of appliances, models and brands. Understanding the consumer and shopper trends is still in its infancy stage within this segment of the market. This study focuses on investigating the use of effective online engagement and the ability to understand how online interaction changes consumers’ behaviour among an appliance brand’s customers which constitute the sample of the study. How the group can understand the full route to market and best make use of segments for engagement was also investigated. A survey was conducted where questionnaire was administrated via the group’s page on Facebook and consisted of opinion-based questions on the perception of Facebook as a medium to influence consumer behaviour. The results of the survey revealed that potential consumers who use Facebook do engage with appliance brands and manufactures, and they admit that engaging with them on Facebook influences their behaviour around appliances

    Model Configuration And Data Management In The Short-Term Water Information Forecasting Tools

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    The Short-term Water Information and Forecasting Tools (SWIFT) is a suite of tools for flood and short-term streamflow forecasting, consisting of a collection of hydrologic model components and utilities. Catchments are modeled using conceptual subareas and a node-link structure for channel routing. The tools comprise modules for calibration, model state updating, output error correction, ensemble runs and data assimilation. Given the combinatorial nature of the modelling experiments and the sub-daily time steps typically used for simulations, the volume of model configurations and time series data is substantial and its management is not trivial. SWIFT is currently used mostly for research purposes but has also been used operationally, with intersecting but significantly different requirements. Early versions of SWIFT used mostly ad-hoc text files handled via Fortran code, with limited use of netCDF for time series data. The configuration and data handling modules have since been redesigned. The model configuration now follows a design where the data model is decoupled from the on-disk persistence mechanism. For research purposes the preferred on-disk format is JSON, to leverage numerous software libraries in a variety of languages, while retaining the legacy option of custom tab-separated text formats when it is a preferred access arrangement for the researcher. By decoupling data model and data persistence, it is much easier to interchangeably use for instance relational databases to provide stricter provenance and audit trail capabilities in an operational flood forecasting context. For the time series data, given the volume and required throughput, text based formats are usually inadequate. A schema derived from CF conventions has been designed to efficiently handle time series for SWIFT

    Pixel-z: Studying Substructure and Stellar Populations in Galaxies out to z~3 using Pixel Colors I. Systematics

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    We perform a pixel-by-pixel analysis of 467 galaxies in the GOODS-VIMOS survey to study systematic effects in extracting properties of stellar populations (age, dust, metallicity and SFR) from pixel colors using the pixel-z method. The systematics studied include the effect of the input stellar population synthesis model, passband limitations and differences between individual SED fits to pixels and global SED-fitting to a galaxy's colors. We find that with optical-only colors, the systematic errors due to differences among the models are well constrained. The largest impact on the age and SFR e-folding time estimates in the pixels arises from differences between the Maraston models and the Bruzual&Charlot models, when optical colors are used. This results in systematic differences larger than the 2{\sigma} uncertainties in over 10 percent of all pixels in the galaxy sample. The effect of restricting the available passbands is more severe. In 26 percent of pixels in the full sample, passband limitations result in systematic biases in the age estimates which are larger than the 2{\sigma} uncertainties. Systematic effects from model differences are reexamined using Near-IR colors for a subsample of 46 galaxies in the GOODS-NICMOS survey. For z > 1, the observed optical/NIR colors span the rest frame UV-optical SED, and the use of different models does not significantly bias the estimates of the stellar population parameters compared to using optical-only colors. We then illustrate how pixel-z can be applied robustly to make detailed studies of substructure in high redshift galaxies such as (a) radial gradients of age, SFR, sSFR and dust and (b) the distribution of these properties within subcomponents such as spiral arms and clumps. Finally, we show preliminary results from the CANDELS survey illustrating how the new HST/WFC3 data can be exploited to probe substructure in z~1-3 galaxies.Comment: 37 pages, 21 figures, submitted to Ap

    The influence of leadership styles on employee performance in construction firms

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    Currently, there is a dearth of research, examining how project managers' leadership styles influence the performance of construction company workers in Cape Town. Other research has discussed this subject on a national or international level. Still, comprehensive data on Cape Town construction firms is lacking. This has prevented local enterprises from understanding the role of their project managers’ leadership styles on employee performance outcomes. This article sought to ascertain how leadership styles influence employee performance in construction firms and to develop a conceptual framework for improving leadership and performance. Through quantitative techniques, 456 questionnaires were distributed at construction sites across Cape Town. Responses were then analysed using an ANOVA test (with the descriptive and regressive methods) and a post-hoc test (using the Bonferroni Method) and correlation analysis. The results reveal a statistically significant positive relationship between project managers’ leadership styles and the performance of subordinate employees. These findings have subsequently been used to develop a conceptual framework of leadership quality development tools, including training, empowerment, coaching, participation, and delegation. The research contributes to new knowledge that will promote local project managers’ leadership development, improve employee performance, and in doing so, increase successful project outcomes across the city

    Human treadmill walking needs attention

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    BACKGROUND: The aim of the study was to assess the attentional requirements of steady state treadmill walking in human subjects using a dual task paradigm. The extent of decrement of a secondary (cognitive) RT task provides a measure of the attentional resources required to maintain performance of the primary (locomotor) task. Varying the level of difficulty of the reaction time (RT) task is used to verify the priority of allocation of attentional resources. METHODS: 11 healthy adult subjects were required to walk while simultaneously performing a RT task. Participants were instructed to bite a pressure transducer placed in the mouth as quickly as possible in response to an unpredictable electrical stimulation applied on the back of the neck. Each subject was tested under five different experimental conditions: simple RT task alone and while walking, recognition RT task alone and while walking, walking alone. A foot switch system composed of a pressure sensitive sensor was placed under the heel and forefoot of each foot to determine the gait cycle duration. RESULTS: Gait cycle duration was unchanged (p > 0.05) by the addition of the RT task. Regardless of the level of difficulty of the RT task, the RTs were longer during treadmill walking than in sitting conditions (p < 0.01) indicating that an increased amount of resources are required for the maintainance of walking performance on a treadmill at a steady state. No interaction (p > 0.05) was found between the attentional demand of the walking task and the decrement of performance found in the RT task under varying levels of difficulty. This finding suggests that the healthy subjects prioritized the control of walking at the expense of cognitive performance. CONCLUSION: We conclude that treadmill walking in young adults is not a purely automatic task. The methodology and outcome measures used in this study provide an assessment of the attentional resources required by walking on the treadmill at a steady state
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