Showing 1711 - 1720 of 5831 Items
Data associated with Walter-McNeill et al. (2021) Oecologia https://doi.org/10.1007/s00442-021-05038-y
Date: 2021-01-01
Creator: Barry Logan
Access: Open access
Sri Lanka in 2018: Seeking a way forward
Date: 2019-02-01
Creator: Sree Padma
Access: Open access
- The highlight of Maithripala Sirisena's presidency came in its very beginning when he ended a decade of autocracy by restoring democracy. And when rivalry with his own prime minister, Ranil Wickremesinghe, devolved into a constitutional crisis, Sirisena was forced to abide by the democratic norms he had restored.
Bilateral consequences of chronic unilateral deafferentation in the auditory system of the cricket gryllus bimaculatus
Date: 2011-04-01
Creator: Hadley Wilson Horch, Elizabeth Sheldon, Claire C. Cutting, Claire R. Williams, Dana M., Riker, Hannah R. Peckler, Rohit B. Sangal
Access: Open access
- The auditory system of the cricket has the unusual ability to respond to deafferentation by compensatory growth and synapse formation. Auditory interneurons such as ascending neuron 2 (AN-2) in the cricket Gryllus bimaculatus possess a dendritic arbor that normally grows up to, but not over, the midline of the prothoracic ganglion. After chronic deafferentation throughout larval development, however, the AN-2 dendritic arbor changes dramatically, and medial dendrites sprout across the midline where they form compensatory synapses with the auditory afferents from the contralateral ear. We quantified the extent of the effects of chronic, unilateral deafferentation by measuring several cellular parameters of 3 different neuronal components of the auditory system: the deafferented AN-2, the contralateral (or nondeafferented) AN-2 and the contralateral auditory afferents. Neuronal tracers and confocal microscopy were used to visualize neurons, and double-label experiments were performed to examine the cellular relationship between pairs of cells. Dendritic complexity was quantified using a modified Sholl analysis, and the length and volume of processes and presynaptic varicosities were assessed under control and deafferented conditions. Chronic deafferentation significantly influenced the morphology of all 3 neuronal components examined. The overall dendritic complexity of the deafferented AN-2 dendritic arbor was reduced, while both the contralateral AN-2 dendritic arbor and the remaining, intact, auditory afferents grew longer. We found no significant changes in the volume or density of varicosities after deafferentation. These complex cellular changes after deafferentation are interpreted in the light of the reported differential regulation of vesicle-associated membrane protein and semaphorin 2a. Copyright © 2011 S. Karger AG, Basel.
Baroque Paintings from the Collection of Walter P. Chrysler, Jr.
Date: 1963-01-01
Access: Open access
- This catalogue is in lieu of Bulletin vol. II: no. 3.
Sri Lanka in 2017: Sluggish on many fronts
Date: 2018-01-01
Creator: Sree Padma
Access: Open access
- Sri Lanka's 69-year-old parliamentary democracy continues with power concentrated at the center, and consequently, the country's non-Sinhala-Buddhist minorities on the periphery continue to press for equal rights, while ethnic strife hinders prospects for unified progress. Maithripala Sirisena, president since 2015, promises reconciliation but has received little cooperation from the majority Sinhala Buddhists.
An empirical study of memory sharing in virtual machines
Date: 2019-01-01
Creator: Sean Barker, Timothy Wood, Prashant Shenoy, Ramesh Sitaraman
Access: Open access
- Content-based page sharing is a technique often used in virtualized environments to reduce server memory requirements. Many systems have been proposed to capture the benefits of page sharing. However, there have been few analyses of page sharing in general, both considering its real-world utility and typical sources of sharing potential. We provide insight into this issue through an exploration and analysis of memory traces captured from real user machines and controlled virtual machines. First, we observe that absolute sharing levels (excluding zero pages) generally remain under 15%, contrasting with prior work that has often reported savings of 30% or more. Second, we find that sharing within individual machines often accounts for nearly all (>90%) of the sharing potential within a set of machines, with inter-machine sharing contributing only a small amount. Moreover, even small differences between machines significantly reduce what little inter-machine sharing might otherwise be possible. Third, we find that OS features like address space layout randomization can further diminish sharing potential. These findings both temper expectations of real-world sharing gains and suggest that sharing efforts may be equally effective if employed within the operating system of a single machine, rather than exclusively targeting groups of virtual machines.
The Art Gallery Theorem for Polyominoes
Date: 2012-10-01
Creator: Therese Biedl, Mohammad T. Irfan, Justin Iwerks, Joondong Kim, Joseph S.B., Mitchell
Access: Open access
- We explore the art gallery problem for the special case that the domain (gallery) P is an m-polyomino, a polyform whose cells are m unit squares. We study the combinatorics of guarding polyominoes in terms of the parameter m, in contrast with the traditional parameter n, the number of vertices of P. In particular, we show that ⌊m+1/3⌋ point guards are always sufficient and sometimes necessary to cover an m-polyomino, possibly with holes. When m < 3n/4-4, the sufficiency condition yields a strictly lower guard number than ⌊ n/4⌋, given by the art gallery theorem for orthogonal polygons. © 2012 Springer Science+Business Media, LLC.
Polar oceanography: Engendering students with a sense of place and a sense of time
Date: 2016-06-01
Creator: Collin S. Roesler
Access: Open access