353 research outputs found
Countee Cullen-Harold Jackman Memorial Collection
No full textThe Cullen Jackman Memorial Collection (1881-1995) documents the artistic and creative nature of those of African descent. A series of note within this collection are the photographs by Carl Van Vechten, an American writer, artistic photographer, and patron of the Harlem Renaissance. An appreciator of the arts, Van Vechten promoted many of the major figures of the Renaissance through his photography, including Langston Hughes, Paul Robeson, Rose McClendon, and Ethel Waters.
At the AUC Robert W. Woodruff Library we are always striving to improve our digital collections. We welcome additional information about people, places, or events depicted in any of the works in this collection. To submit information, please contact us at [email protected]
The implications of grassland and heathland management for the conservation of spider communities: a review
No full textBoth intensity and type of habitat management in grasslands and heathlands affect spider communities. With high intensity management, spider communities often lack diversity and are dominated by a few r-selected species affiliated with bare ground. Low intensity management produces more complex communities introducing more niches for aerial web spinners and climbing spiders. The preferred management will be site-dependent and may not be appropriate for all spiders in all situations, particularly for some rare or threatened species. Providing natural cover is recommended when using extreme forms of management or intensive grazing (particularly by sheep). In extreme cases, or where trampling is heavy, the litter layer should be conserved. We advocate research and survey before and after major management implementation. Habitat management for spiders should not be considered alone, but integrated into a holistic plan. Management for spiders may conflict with rare plant conservation and small reserves should examine the viability of providing two contrasting regimes
Fibonacci s-Cullen and s-Woodall Numbers
No full textAbstract The m-th Cullen number C m is a number of the form m2 m + 1 and the m-th Woodall number W m has the form m2 m − 1. In 2003, Luca and Stȃnicȃ proved that the largest Fibonacci number in the Cullen sequence is F 4 = 3 and that F 1 = F 2 = 1 are the largest Fibonacci numbers in the Woodall sequence. Very recently, the second author proved that, for any given s > 1, the equation F n = ms m ± 1 has only finitely many solutions, and they are effectively computable. In this note, we shall provide the explicit form of the possible solutions
Spider communities as tools in monitoring reclaimed limestone quarry landforms
No full textSpider communities are sensitive to a wide range of environmental factors and are potential ecological indicators which may be effective in the assessment and monitoring of restored ecosystems. One restoration technique of disused limestone quarry faces, landform replication, attempts to create landforms and ecosystems similar to those found on natural dalesides. Vegetation surveys indicate that communities developing on landform replications are more closely allied to natural dalesides than are those of naturally recolonised disused quarries. Assessment of the spider communities of three landform replication sites, a natural limestone daleside and seven naturally recolonised disused limestone quarries, using DECORANA and TWINSPAN, produced differing patterns of sites than those observed through the assessment of the vegetation communities. DECORANA assessment based on vascular plant species composition highlights the similarities between daleside and reclaimed site communities. The sensitivity of spider communities to vegetation structure and extent of bare ground highlights differences between sites and provides evidence of important differences in vegetation community development particularly in relation to cover and structure. Implications for the assessment of reclamation and restoration techniques are discussed
Ultrastructural findings in feline corneal sequestra
No full textObjectives (1) To describe the ultrastructural features of corneal sequestra in cats; and (2) to enhance our understanding regarding the pathogenesis of feline corneal sequestration. Methods Nine corneal sequestra were harvested via keratectomy from globes of nine cats. The sequestra were routinely fixed then postfixed for high resolution light and transmission electron microscopy (HR-LM and TEM, respectively). The tissues were embedded in Epon/Araldite. Sections of 0.5-mu m thickness were cut and stained with 1% toluidine blue in 1% sodium tetraborate solution for HR-LM. Ultrathin sections were collected on copper grids and stained with uranyl acetate and Sato's lead stain for TEM. Ultrathin sections were examined and the images were captured on an Advantage HR CCD camera using a Hitachi 7500 electron microscope operated at 80 kV. Two healthy corneas from two cats were harvested immediately following euthanasia. These corneal tissues (control samples) were processed in the same manner as the corneal sequestra for HR-LM and TEM. A portion of each sequestrum was also submitted for polymerase chain reaction (PCR) testing for infectious agents including feline herpesvirus-1 (FHV-1), Toxoplasma gondii, Chlamydophila felis and Mycoplasma spp. Results Ultrastructure of healthy corneal tissues revealed basal corneal epithelial cells aligned adjacent to a thin acellular layer similar to Bowman's layer with underlying tightly packed, regularly arranged, collagen fibrils oriented in different planes. Keratocytes were elongated and had long and irregularly shaped nuclei, and cytoplasm contained rough endoplasmic reticulum and abundant membrane-bound vesicles. In contrast, corneal sequestra contained varying amounts of an amorphous, electron-dense substance, continuous with intact basal epithelial basement membranes peripherally, and overlying corneal ulceration and loosely packed collagen fibrils. Remnants of necrotic keratocytes were seen in spaces between disarranged collagen layers. In all samples, occasional keratocytes exhibited morphology indicative of apoptosis including clumping and margination of chromatin, and shrunken cytoplasm. Varying degrees of inflammation were noted on HR-LM and TEM of affected corneas including peri- and intralesional neutrophils, lymphocytes, plasma cells, and macrophages. Corneal sequestra were FHV-1-positive (n = 3), FHV-1- and T. gondii-positive (n = 1), T. gondii-positive (n = 3), or negative for DNA of these infectious agents (n = 2) using PCR. All corneal sequestra were negative for DNA of Chlamydophila felis and Mycoplasma spp. using PCR. Conclusions Apoptosis may play a role in the pathogenesis of feline corneal sequestration independent of the presence of DNA of these infectious organisms. Prospective clinical studies are warranted to further understand the significance of T. gondii in relation to feline corneal sequestration.PT: J; CR: AOUIZERATE F, 1993, BRIT J OPHTHALMOL, V77, P107 BELAK S, 1993, VET RES COMMUN, V17, P55 BURNEY DP, 1998, VET PARASITOL, V79, P181 BURNEY DP, 1999, J PARASITOL, V85, P947 CHAN CC, 1994, AM J OPHTHALMOL, V117, P803 CHAVKIN MJ, 1992, PROGR VET COMP OPHTH, V2, P29 CULLEN CL, 1999, VET OPHTHALMOLOGY, V2, P197 DAVIDSON MG, 1993, INVEST OPHTH VIS SCI, V34, P3653 DAVIDSON MG, 1998, VET OPHTHALMOLOGY, V1, P71 DEPRAETERE V, 1997, SEMIN IMMUNOL, V9, P93 DUBEY JP, 1987, VET CLIN N AM-SMALL, V17, P1389 DUBEY JP, 1993, J AM VET MED ASSOC, V203, P1556 EJIMA H, 1993, J VET MED SCI, V55, P1051 FEATHERSTONE HJ, 2004, VET OPHTHALMOL, V7, P229 GELATT KN, 1971, VET MED SMALL ANIMAL, V66, P561 GELATT KN, 1973, J AM ANIM HOSP ASSOC, V9, P204 GEMENSKY AJ, 2001, J AM VET MED ASSOC, V219, P1550 GEMENSKY AJ, 2001, J AM VET MED ASSOC, V219, P1568 HAKANSON NE, 1994, VET COMP OPHTHALMOL, V4, P179 HU SX, 2001, CHINESE MED J-PEKING, V114, P640 JONES CD, 2000, INVEST OPHTH VIS SCI, V41, P634 LAPPIN MR, 1989, AM J VET RES, V50, P1586 LAPPIN MR, 1993, AM J VET RES, V54, P415 LAPPIN MR, 1996, AM J VET RES, V57, P1589 MAGGS DJ, 1999, AM J VET RES, V60, P932 MATSUBARA M, 1991, INVEST OPHTH VIS SCI, V32, P3221 MOHAN RR, 1997, EXP EYE RES, V65, P575 MORGAN RV, 1994, J AM ANIM HOSP ASSOC, V30, P24 NASISSE MP, 1998, AM J VET RES, V59, P856 PODSKOCHY A, 2002, CORNEA, V21, P91 SOURI EN, 1975, VET MED SMALL ANIM C, V70, P531 STARTUP FG, 1988, J SMALL ANIM PRACT, V29, P476 STILES J, 1996, AM J VET RES, V57, P264 STILES J, 1997, AM J VET RES, V58, P338 WILSON SE, 1997, EXP EYE RES, V64, P775 YASUHARA S, 2003, J HISTOCHEM CYTOCHEM, V51, P873; NR: 36; TC: 0; J9: VET OPHTHALMOL; PG: 9; GA: 964WASource type: Prin
Pseudoscorpions in Field Margins: Effects of Margin Age, Management and Boundary Habitats
No full textVolume: 27Start Page: 236End Page: 24
Providing students with formative audio feedback
No full textThe provision of timely and constructive feedback is increasingly challenging for busy academics. Ensuring effective student engagement with feedback is equally difficult. Increasingly, studies have explored provision of audio recorded feedback to enhance effectiveness and engagement with feedback. Few, if any, of these focus on purely formative audio feedback on draft submissions of written assignments. This study encouraged a cohort of 40 students to submit drafts of written assignments, two weeks before formal submission, in order to receive audio recorded feedback. Nearly half the cohort either did not submit drafts or submitted only brief outlines. The level of draft completeness impacted on the characteristics of the lecturer's feedback. While students receiving audio feedback gained significantly higher marks for finished work, this cannot be directly attributed to receipt/use of feedback as analysis suggests generally more able students are more likely to submit more complete drafts, which leads us to ask the question, are we simply helping better students to perform even better? Audio feedback was reported as clear, engaging and helpful; however, timing of feedback (before formal submission) may be of greater importance in terms of impact on attainment than the audio format. We suggest a model that focuses efforts on formative feedback (in advance of formal submission) and selective provision of summative feedback (targeted feed forward). © 2013 G. Scott, The Higher Education Academy
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