1,507 research outputs found
Reviewing the Author-Function in the Age of Wikipedia
No full textIn Reviewing the Author-Function in the Age of Wikipedia, Amit Ray and Erhardt Graeff examine how wiki technology challenges traditional concepts of authorship and authority in knowledge production. The authors build on poststructuralist theory, particularly Roland Barthes\u27s Death of the Author and Michel Foucault\u27s concept of the author-function, to analyze how wikis destabilize individual authorship in favor of collaborative, community-driven content creation.
The essay argues that wikis represent a fundamental shift from the Romantic notion of the solitary author-genius to what they term the wiki writing process —a dynamic system where traditional roles of reader, writer, and editor blur into a unified community of users. Using Wikipedia as a primary case study, the authors demonstrate how the platform\u27s structure (article, discussion, and history pages) creates a digital palimpsest that archives all contributions while enabling continuous revision.
Through analysis of Wikipedia\u27s editing patterns and community oversight mechanisms, Ray and Graeff show how wikis embody poststructuralist principles in practice, creating what they call serial collaborations that exist in perpetual flux. The authors conclude that wikis represent an evolved form of textual production that realizes Foucault\u27s vision of discourse freed from traditional authorial constraints, offering new possibilities for collaborative knowledge creation while challenging established notions of intellectual authority and ownership
Cyclotella utahensis Graeff, Kociolek & S. R. Rushforth 2013, sp. nov.
No full textCyclotella utahensis Graeff, Kociolek & S.R. Rushforth, sp. nov. (Figs 1–18; figure 5 = holotype) Valve face circular, 5–13 µm in diameter, strongly tangentially undulate (Figs 2–6). Costa-like ornamentation restricted to the outer ⅓ of the valve face, appearing dichotomously branched near the margin in most valves (Figs 2–4) except on the largest and smallest specimens. Fascicles number 10–13/ 10 µm. Each fascicle contains 3–5 striae (Figs 9, 10). Undulations in the center of the valve appear mottled (Figs 2–5) and possess 1–2 central strutted processes (fultoportulae) (Figs 13–15). Fultoportulae are evident around the margin of the valve, 4–6/ 10 µm (Figs 12–13). In the SEM, the mottled appearance of the valve center is conspicuous (Figs 9–10). The external opening of the central fultoportula sometimes has a narrow rim about it (Fig. 10, white arrow). Siliceous conical nodules form one ring on the very margin of the valve and one ring about ½ the way down the striae (Figs 10, 12). The striae are sometimes pushed together into 2–3 striae within a fascicle separated from other fascicles by hyaline strips, but each stria is composed of two rows of areolae that terminate about ¼–⅓ from the margin (Figs 9–10). Prominent elevations are present (Figs 11–12). Between the elevations with striae, unornamented ribs occur that have the external openings of the marginal fultoportulae (Fig. 12, white arrows). These openings can also be surrounded by a slightly thickened rim. The external opening for the rimoportula is round and smaller than the openings of the marginal fultoportulae, with a noticeable thickening around the rim (Figs 9, 12, black arrows). The cingulum is composed of at least several, narrow open bands with one or more rows of small pores along the pars exterior (Fig. 11). Internally the central fultoportulae each have three satellite pores (Figs 13–15). There are primary ribs that are thicker, and between them are thinner, more recessed secondary ribs (Figs 13, 15, 17). A single, sessile rimoportula is present on one of the primary ribs (Fig. 13, black arrow, Figs 17–18). Marginal fultoportulae are present on the secondary ribs, each with three satellite pores (Figs 13, 15, 17). Areolae are evident between the ribs and seen to possess flat cribra (Figs 13, 16). Type: — USA. Blue Lake, Tooele Co., Utah (COLO 439031, holotype! (= Fig. 5), designated here; COLO 8504, BM 101675, isotypes). Etymology:—Named for the state in which it was found. Distribution: — Cyclotella utahensis is abundant in the plankton of the main basin of Blue Lake (COLO 8504). Observations: — This taxon resembles others in the genus that have strongly tangentially undulate valves, both fossil and recent. For example, Khursevich & Kociolek (2008) and Kociolek & Khursevich (2013) described several species attributed to Cyclotella, such as C. idahica Khursevich & Kociolek (in Kociolek & Khursevich 2103: 83) and C. oregonica Kociolek & Khursevich (in Khursevich & Kociolek 2008: 44) that are similar to this new species, differing mostly in the structure of the punctate portion of the outer part of the valve exterior. This new species differs from C. scaldensis Muylaert & Sabbe (1996: 336) and C. striata (Kütz.) Grunow (in Cleve & Grunow 1880: 119; basionym: Coscinodiscus striatus Kützing 1844: 131), two estuarine species, in the structure of the striae. In addition, C. scaldensis has a very long rimoportula (Muylaert & Sabbe 1996) that is absent in C. utahensis, while C. striata has finer striae and fascicles as well as a different pattern of ornamentation in the center of the valve (Häkansson 1996). Houk et al. (2010) listed three morphological groups within Cyclotella, and C. utahensis would be included in their group 1, which includes the generitype of Cyclotella. Other Recent Cyclotella species with tangentially undulate valve faces and lacking areolae in the center of the valve usually have smooth (not bumpy) central areas, similar to the generitype, C. distinguenda Hustedt (1927: 320) (e.g. Krammer & Lange-Bertalot 1991).Published as part of GRAEFF, C. L., KOCIOLEK, J. P. & RUSHFORTH, S. R., 2013, New and Interesting Diatoms (Bacillariophyta) from Blue Lake Warm Springs, Tooele County, Utah, pp. 1-38 in Phytotaxa 153 (1) on pages 2-3, DOI: 10.11646/phytotaxa.153.1.1, http://zenodo.org/record/510068
FIGURES 64–69 in New and Interesting Diatoms (Bacillariophyta) from Blue Lake Warm Springs, Tooele County, Utah
No full textFIGURES 64–69. LM. Naviculonema stagnora. Valve views showing the size diminution series. Figure 67 is the holotype. Scale bar: 10 µm.Published as part of GRAEFF, C. L., KOCIOLEK, J.P. & RUSHFORTH, S.R., 2013, New and Interesting Diatoms (Bacillariophyta) from Blue Lake Warm Springs, Tooele County, Utah, pp. 1-38 in Phytotaxa 153 (1) on page 14, DOI: 10.11646/phytotaxa.153.1.1, http://zenodo.org/record/510068
Multigating, a 4D optimized beam tracking in scanned ion beam therapy
No full textThe treatment of moving tumors with a scanned ion beam is challenging due to interplay effects and changing beam range. We propose multigating, as a method for 4D-treatment optimization and delivery. In 3D beam tracking, tracking vectors are added during delivery to beam spot positions based on the detected motion phase. This has the disadvantage of dose errors in case of complex motion patterns and an uncertain out-of-target dose distribution. In multigating, the motion phase for each beam spot is predefined, which allows to add the tracking vector prior to beam weight optimization on all motion phases. The synchronization of delivery and target motion is assured by fast gating. The feasibility of the delivery was shown in a film experiment and required only minor software modification to the treatment planning system. In a treatment planning study in 4 lung cancer patients, target coverage could be restored to the level of a static reference plan by multigating (V95. 99%) but not by standard beam tracking (V95, 95%). The conformity of the multigating plans was only slightly lower than those of the static plan, with a conformity number of 72.0% (median, range 64.6-76.6%) compared to 75.8% (70.8-81.5%) in spite of target motion of up to 22 mm. In conclusion, we showed the technical feasibility of multigating, a 4D-optimization and delivery method using scanned beams that allows for conformal and homogeneous dose delivery to moving targets also in case of complex motion. © Adenine Press (2014)
FIGURES 9–12. SEM. Cyclotella utahensis. External and girdle views. Fig. 9 in New and Interesting Diatoms (Bacillariophyta) from Blue Lake Warm Springs, Tooele County, Utah
No full textFIGURES 9–12. SEM. Cyclotella utahensis. External and girdle views. Fig. 9, Full valve view showing undulate and mottled valve face. Fig. 10, Full valve view showing external opening of the central fultoportula (white arrow). Fig. 11, Girdle view showing open girdle bands. Fig. 12, External view with nodules and external openings of the marginal fultoportulae (white arrows) and the rimoportula (black arrow). Scale bars: 1 µm.Published as part of GRAEFF, C. L., KOCIOLEK, J.P. & RUSHFORTH, S.R., 2013, New and Interesting Diatoms (Bacillariophyta) from Blue Lake Warm Springs, Tooele County, Utah, pp. 1-38 in Phytotaxa 153 (1) on page 4, DOI: 10.11646/phytotaxa.153.1.1, http://zenodo.org/record/510068
FIGURES 33–37 SEM. Williamsella angusta. Internal views showing valves from five specimens. Fig. 33 in New and Interesting Diatoms (Bacillariophyta) from Blue Lake Warm Springs, Tooele County, Utah
No full textFIGURES 33–37 SEM. Williamsella angusta. Internal views showing valves from five specimens. Fig. 33, Full valve view of a large specimen with subcapitate apices. Fig. 34, Apex showing the raised rimoportula. Fig. 35, Apex showing the linear opening of the rimoportula. Fig. 36, An apex without a rimoportula. Fig. 37, Unpaired striae and shortened striae near the valve center. Scale bars: Fig. 33: 10 µm; Figs. 34–37: 0.5 µm.Published as part of GRAEFF, C. L., KOCIOLEK, J.P. & RUSHFORTH, S.R., 2013, New and Interesting Diatoms (Bacillariophyta) from Blue Lake Warm Springs, Tooele County, Utah, pp. 1-38 in Phytotaxa 153 (1) on page 8, DOI: 10.11646/phytotaxa.153.1.1, http://zenodo.org/record/510068
FIGURES 70–72 in New and Interesting Diatoms (Bacillariophyta) from Blue Lake Warm Springs, Tooele County, Utah
No full textFIGURES 70–72. SEM. Naviculonema stagnora. External valve views of two specimens. Fig. 70, Full external valve with distal raphe ends deflected in the same direction and irregularly-shaped central area. Fig. 71, C-shaped, occluded areolae. Fig 72, Straight proximal raphe ends and an isolated areola at the central area. Scale bars: Fig. 70: 5 µm; Figs 71–72: 1 µm.Published as part of <i>GRAEFF, C. L., KOCIOLEK, J.P. & RUSHFORTH, S.R., 2013, New and Interesting Diatoms (Bacillariophyta) from Blue Lake Warm Springs, Tooele County, Utah, pp. 1-38 in Phytotaxa 153 (1)</i> on page 15, DOI: 10.11646/phytotaxa.153.1.1, <a href="http://zenodo.org/record/5100682">http://zenodo.org/record/5100682</a>
FIGURES 145–150 in New and Interesting Diatoms (Bacillariophyta) from Blue Lake Warm Springs, Tooele County, Utah
No full textFIGURES 145–150. SEM. Nitzschia vitrea. External views of six specimens. Fig. 145, View of the valve face with interrupted striae. Fig. 146, Girdle view of a valve showing the prominent keel and constriction at the valve center. Fig. 147, Valve view of the apex with the raphe positioned at the top of the keel. Fig. 148, Side view of the apex showing a complete row of areolae closest to the raphe and the hyaline region along the edge of the mantle. Fig. 149, Valve center with continuous raphe. Fig. 150, Broken valve showing the areola openings narrowing on inside of the valve. Scale bars: Figs 145–146: 20 µm; Figs 147–150: 1 µm.Published as part of GRAEFF, C. L., KOCIOLEK, J.P. & RUSHFORTH, S.R., 2013, New and Interesting Diatoms (Bacillariophyta) from Blue Lake Warm Springs, Tooele County, Utah, pp. 1-38 in Phytotaxa 153 (1) on page 30, DOI: 10.11646/phytotaxa.153.1.1, http://zenodo.org/record/510068
Robust treatment planning with 4D intensity modulated carbon ion therapy for multiple targets in stage IV non-small cell lung cancer
No full textIntensity modulated particle therapy (IMPT) with carbon ions can generate highly conformal treatment plans; however, IMPT is limited in robustness against range and positioning uncertainty. This is particularly true for moving targets, even though all motion states of a 4DCT are considered in 4D-IMPT. Here, we expand 4D-IMPT to include robust non-linear RBE-weighted optimization to explore its potential in improving plan robustness and sparing critical organs. In this study, robust 4D-optimization - based on worst-case optimization on 9 scenarios - was compared to conventional 4D-optimization with PTV margins using 4D dose calculation and robustness analysis for 21 uncertainty scenarios. Slice-by-slice rescanning was used for motion mitigation. Both 4D-optimization strategies were tested on a cohort of 8 multi-lesion lung cancer patients with the goal of prioritizing OAR sparing in a hypofractionated treatment plan. Planning objectives were to keep the OAR volume doses below corresponding limits while simultaneously achieve CTV coverage with D95% ≥ 95 %. For the conventional plans, average D95% was at 98.7% which fulfilled the target objective in 83.2% of scenarios. For the robust plans, average D95% was reduced to 97.6% which still fulfilled the target objective in 80.7% of cases, but led to significantly improved overall OAR sparing: Volume doses were below the limits in 96.2% of cases for the conventional and 99.5% for the robust plans. When considering the particularly critical smaller airways only, fulfillment rates could be increased from 76.2% to 96% for the robust plans. This study has shown that plan robustness of 4D-IMPT could be improved by using robust 4D-optimization, offering greater control over uncertainties in the actual delivered dose. In some cases, this required sacrificing target coverage for the benefit of better OAR sparing
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