196,450 research outputs found
Wirt, Frederick M., and Michael W. Kirst, Curricular Decisions in the Political System, pp. 202-225 in Fredrick M.Wirt and Michael W. Kirst, The Political Web of American Schools . Boston: Little Brown and Co, 1972. Revised edition, 1975, under the title Political and Social Foundations of Education. Berkley, CA: McCutchan.
No full textRevises and extends their 1971 RER article, An Analysis of Curriculum Policy-Making. (Kirst, first author
Ropalomera albifaciata Kirst & Ale-Rocha, new species
No full textRopalomera albifaciata Kirst & Ale-Rocha, new species Holotype male. Body: 10.1 mm; wing: 9.9 mm Head: Frons predominantly yellow, with brown spots on the sides and around insertion of antenna; thin, darkbrown pilosity; two spots of silver pollinosity covering the ocellar region to the vertex; eye circumference with silver pollinosity. Ocellar tubercle dark brown, shiny and with pair of thin bristles. Postocellar bristles divergent. Postocular bristles present. Antenna with dark-brown, very short scape; pedicel mostly dark brown with orange apical margin, size twice that of scape, and anterior margin haired and with one short dorsal bristle; flagellomere dark brown with orange base; arista plumose with long hairs, color dark brown with basal third orange. Gena broad, yellow, silver pollinose and with slender golden bristles that are longer ventrally. Parafacialia dark brown below and yellow above, with dark-brown pilosity and four distinct bristles. Face white, matte, with globose facial tubercle. Clypeus light brown. Palpus brown with sparse small dark setae and larger setae ventrally. Thorax: Scutum brown with acrostichal and dorsocentral stripes of pale golden pollinosity. Scutellum trapezoidal, directed slightly upward; dorsal surface concave, rounded posteriorly, bright and without pollinosity, sides with golden pollinosity basally. Mesopleuron with silver pollinose stripe extending to anepisternum. Chaetotaxy: one postpronotal, two notopleural, one weak presutural supra-alar, one postsutural supra-alar, one postalar, one intra-alar, one intra-postalar, one weak dorsocentral and one acrostichal; one pair of apical and one pair of lateral scutellar bristles. Mesopleuron with one strong bristle on anepisternum; one bristle on katepisternum and with long dark pilosity on ventral surface; one distinct seta on posterior margin of posterior spiracle. Legs: Coxae with silver pollinosity. Femora dark brown. Fore femur with slender bristles that are longer on ventral surface. Mid femur with long slender bristles ventrally on proximal region, a series of seven spine-like setae on distal half of anteroventral surface that decrease in size toward apex, distal half of dorsal surface with strong non-aligned bristles and two apical setae. Hind femur with silver pollinosity on dorsal surface, short slender dorsal bristles and long ventral bristles, five strong non-aligned bristles on anterior surface, and four distal, spine-like anteroventral setae. Tibiae brown; fore tibia with dense red anteroventral hairs and long, fine, brown posterior bristles on distal third. Mid tibia with longer ventral bristles on proximal half, and with apical spine-like bristle on ventral protuberance. Hind tibia with dorsal ridge, five long, strong bristles on the ridge and long, slender bristles on anterior surface. First three tarsomeres yellowish, remaining tarsomeres with dorsal and ventral surface brown with dense golden pubescence. Wing: Infuscated, without distinct spots (Fig. 57). Abdomen: Tergites light brown, with four silver spots of pollinosity on each segment (giving a chessboard appearance). Sternite 5 with sides rounded, and posterior margin straight with short, median invagination flanked by simple, pre-apical row of spine-like bristles (Fig. 1). Terminalia: cerci fused on basal 2 / 3; distal 1 / 3 free and with long, slender bristles laterally (Figs. 2, 3). Surstylus as long as cerci, base wider than apex and inner margin concave (Fig. 4). Paramere trilobed, with apical lobes of same width (Fig. 5). Aedeagus with preapical, spine-like unsclerotized projection (Figs. 6, 7). Epiphallus slightly curved and with very short, acute branches (Figs. 6, 7). Female: Unknown. Type material designate. Holotype male (INPA), labeled: BRASIL, Campus INPA; M[a]n[aus], Am[azonas], Km 4; Data- 03.v. [19] 76, Col[etor] – E. Rufião. Condition of Holotype: not dissected, in perfect condition. 32 Paratypes: BRASIL, Amazonas, Manaus, 11.i. 2004, S. S. M. Menta, 3 (INPA); BR 174, Km 23, EEFT, 12.v. 1997, McPhail, B. Ronchi-Teles, 3 (INPA); Km 40, 23.vi. 97, Mapati, 3 (INPA); same but, 16.v. 97, araçápêra, 3 (INPA); Reserva Adolpho Ducke, 26.ii. 2002, E. F. & A. L. Pinheiro, mata, baixio, Igarapé Barro Branco, 3; same but, 16.x. 2002, 3 (INPA); same but Barro Branco, Melado de cana 10 %, 30m, mata, baixio, 16– 19.viii. 2004, 3 (INPA); same but igarapé Tinga, 11–14.x. 2004, 3 (INPA); same but 16.v. 2003, A. P. Tregue-Costa, área aberta, platô, 15m, Arm. McPhail, 3 (INPA); Conjunto Hiléia, Manta, S. S. M., 03.v. 2004, R. Ale-Rocha, 3 3 (INPA); same but, 24.v. 2004, coletor anônimo, 4 3 (INPA); same but, 03.vi. 2004, 6 3 (INPA); Conj. Campus Elisius, i – ii. 2002, B. Ronchi-Teles, 2 3 (INPA); same but, 03.v. 2004, R. Ale-Rocha, 3 3 (INPA); Conj. Jardim Europa, Bairro Ponta Negra, 15–23.xi. 2002, Arm. de garrafa Pet, A. P. Marques, 3 3 (INPA); Bairro Santa Etelvina, 16.ix. 88, A. C. Ferreira, 3 (INPA); Coari, 1929, A. V. Araújo, 3 (FIOC). Geographical distribution. Brazil (Amazonas). Etymology. From the Latin albus = white, facie = surface and ata = possess, referring to the whitish surface of the face. Variations. Parafacial ranging from yellow to dark brown, but face always white. Discussion. This species resembles Ropalomera femorata in its size, color of body and parafacialia, and the presence of spine-like bristles on sternite 5. However, the face of R. albifaciata sp. nov. is white, and the shape, arrangement and size of the spine-like bristles on sternite 5 are quite different from R. femorata and other species of the genus. Males have the paramere trilobed as in R. femorata, but the aedeagus lacks the pre-apical, spine-like sclerotized projections present in the latter species.Published as part of Kirst, Frederico Dutra & Ale-Rocha, Rosaly, 2012, Taxonomic revision of the Amazonian species of Ropalomera Wiedemann, 1824 (Diptera: Ropalomeridae), pp. 1-27 in Zootaxa 3151 on pages 3-4, DOI: 10.5281/zenodo.27955
From networks of unstable attractors to heteroclinic switching
No full textWe present a dynamical system that naturally exhibits two unstable attractors that are completely enclosed by each other's basin volume. This counterintuitive phenomenon occurs in networks of pulse-coupled oscillators with delayed interactions. We analytically show that upon continuously removing a local noninvertibility of the system, the two unstable attractors become a set of two nonattracting saddle states that are heteroclinically connected. This transition equally occurs from larger networks of unstable attractors to heteroclinic structures and constitutes a new type of singular bifurcation in dynamical systems.Federal Ministry of Education & Research (BMBF) [01GQ0430
Sequential Desynchronization in Networks of Spiking Neurons with Partial Reset
No full textThe response of a neuron to synaptic input strongly depends on whether or not the neuron has just emitted a spike. We propose a neuron model that after spike emission exhibits a partial response to residual input charges and study its collective network dynamics analytically. We uncover a desynchronization mechanism that causes a sequential desynchronization transition: In globally coupled neurons an increase in the strength of the partial response induces a sequence of bifurcations from states with large clusters of synchronously firing neurons, through states with smaller clusters to completely asynchronous spiking. We briefly discuss key consequences of this mechanism for more general networks of biophysical neurons
DMSP lyase in marine macro- and microalgae: interspecific differences in cleavage activity
No full textThe enzymatic cleavage of dimethylsulfoniopropionate (DMSP) to dimethylsulfide (DMS) was investigated in twenty-one strains of marine macro- and microalgae, representing seven algal classes. The enzymes involved in this cleavage are DMSP lyases, producing DMS from DMSP. All algal strains tested were able to synthesize and accumulate various levels of intracellular DMSP but only twelve strains showed DMSP lyase activity. It was possible to identify subgroups of strong and weak DMS producers. The first subgroup included three Enteromorpha species (E. clathrata, E. intestinalis, E. compressa) and Phaeocystis sp. with specific activities in crude cell extracts ranging from 7 to over 100 nmol DMS min-1 (mg cell protein)-1. The second subgroup was composed of a sub-antarctic strain of Acrosiphonia arcta, Polysiphonia lanosa, two strains of Emiliania huxleyi, Acrosiphonia sonderi, Ulva lactuca and Enteromorpha bulbosa. In this subgroup activity ranged from 0.01 to 0.2 nmol DMS min-1 (mg cell protein)-1. No DMSP lyase was detectable in a sub-arctic strain of Acrosiphonia arcta, Acrosiphonia sonderi, Monostroma arcticum, Prasiola crispa, Polysiphonia urceolata, Ascoseira mirabilis, Laminaria saccharina and Tetraselmis subcordiformis. Non-optimal assay conditions and bacterial contamination may have affected rates in some samples, but the results suggest the widespread presence of DMSP lyase among algal taxa, and also raises the possibility that closely-related species may have quite different lyase activities or function
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
Convergence of self-organizing pulse-coupled oscillator synchronization in dynamic networks
No full textThe theory of pulse-coupled oscillators provides a framework to formulate and develop self-organizing synchronization strategies for wireless communications and mobile computing. These strategies show low complexity and are adaptive to changes in the network. Even though several protocols have been proposed and theoretical insight was gained there is no proof that guarantees synchronization of the oscillator phases in general dynamic coupling topologies under technological constraints. Here, we introduce a family of coupling strategies for pulse-coupled oscillators and prove that synchronizationemerges for systems with arbitrary connected and dynamic topologies, individually changing signal propagation and processing delays, and stochastic pulse emission. It is shown by simulations how unreliable links or intentionally incomplete communication between oscillators can improve synchronization performance
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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