Showing 771 - 780 of 2039 Items
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.
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 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.
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.
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.
A two-hybrid assay to study protein interactions within the secretory pathway
Date: 2010-12-01
Creator: Danielle H. Dube
Bin Li
Ethan J. Greenblatt
Sadeieh Nimer
Amanda K., Raymond
Jennifer J. Kohler
Access: Open access
- Interactions of transcriptional activators are difficult to study using transcription-based two-hybrid assays due to potent activation resulting in false positives. Here we report the development of the Golgi two-hybrid (G2H), a method that interrogates protein interactions within the Golgi, where transcriptional activators can be assayed with negligible background. The G2H relies on cell surface glycosylation to report extracellularly on protein-protein interactions occurring within the secretory pathway. In the G2H, protein pairs are fused to modular domains of the reporter glycosyltransferase, Och1p, and proper cell wall formation due to Och1p activity is observed only when a pair of proteins interacts. Cells containing interacting protein pairs are identified by selectable phenotypes associated with Och1p activity and proper cell wall formation: cells that have interacting proteins grow under selective conditions and display weak wheat germ agglutinin (WGA) binding by flow cytometry, whereas cells that lack interacting proteins display stunted growth and strong WGA binding. Using this assay, we detected the interaction between transcription factor MyoD and its binding partner Id2. Interfering mutations along the MyoD:Id2 interaction interface ablated signal in the G2H assay. Furthermore, we used the G2H to detect interactions of the activation domain of Gal4p with a variety of binding partners. Finally, selective conditions were used to enrich for cells encoding interacting partners. The G2H detects protein-protein interactions that cannot be identified via traditional two-hybrid methods and should be broadly useful for probing previously inaccessible subsets of the interactome, including transcriptional activators and proteins that traffic through the secretory pathway. © 2010 Dube et al.
Learning by lending
Date: 2019-01-01
Creator: Matthew Botsch
Victoria Vanasco
Access: Open access
- This paper studies bank learning through repeated interactions with borrowers from a new perspective. To understand learning by lending, we adapt a methodology from labor economics to analyze how loan contract terms evolve as banks acquire new information about borrowers. We construct “proxy” variables for this information using data from borrowers’ out-of-sample, future credit performance. Due to the timing of their construction, banks could not have used these variables directly to price loans. We nonetheless find that these proxies increasingly predict loan prices as relationships progress, even after controlling for possible omitted variable bias. Our methodology provides strong evidence that: (a) bank learning affects loan prices, and (b) relationship benefits are heterogeneous. In particular, higher quality borrowers face differentially lower spreads as their relationship with lenders develop – and banks learn about their quality – while lower quality borrowers see loan prices increase and their loan amounts fall. We further find suggestive evidence that banks incorporate CEO-specific information into loan prices.
Wandering words: Tracing changes in words used by teacher tweeters over time
Date: 2017-01-01
Creator: Stephen Houser
Doris Santoro
Clare Bates Congdon
Jessica Hochman
Access: Open access
- Public school teachers in the United States are often constrained in terms of their ability to express their moral views on issues that affect their schools, classrooms, students, and teaching practices, but are able to express their ideas, concerns, and frustrations as private citizens using social media. Previously we developed the Tweet Capture and Clustering System (TCCS) in order to explore how teachers use Twitter, looking at word usage among a group of teacher tweeters, and attempting to find clusters of teachers who have similar patterns of word usage in their tweets. In the work reported here, we look at teacher tweeters across the 12 months of 2016, seeking to understand how the clusters and the words used in these clusters vary from month to month. In this initial look at the dynamics of the system, we see some evidence of word usage changing across the 12-month period. This initial work suggests that extending TCCS to have temporal topic tracing as a core capability will be a meaningful addition to of the system. Copyright held by the author(s).
The Free-Trade Doctrine and Commercial Diplomacy of Condy Raguet
Date: 2011-05-11
Creator: Stephen Meardon
Access: Open access
- Condy Raguet (1784-1842) was the first Chargé d’Affaires from the United States to Brazil and a conspicuous author of political economy from the 1820s to the early 1840s. He contributed to the era’s free-trade doctrine as editor of influential periodicals, most notably The Banner of the Constitution. Before leading the free-trade cause, however, he was poised to negotiate a reciprocity treaty between the United States and Brazil, acting under the authority of Secretary of State and protectionist apostle Henry Clay. Raguet’s career and ideas provide a window into the uncertain relationship of reciprocity to the cause of free trade.
On kindleberger and hegemony: From berlin to MIT and back
Date: 2014-01-01
Creator: Stephen Meardon
Access: Open access
- The most conspicuous idea of Charles P. Kindleberger’s later career is the value of a single country acting as stabilizer of an international economy prone to instability. It runs through his widely read books, The World in Depression, 1929-1939 (1973), Manias, Panics, and Crashes (1978), A Financial History of Western Europe (1984), and kindred works. This essay traces Kindleberger’s attachment to the idea of “hegemonic stability” back to his tenure as chief of the State Department’s Division of German and Austrian Economic Affairs from 1945 to 1947 and adviser to the European Recovery Program from 1947 to 1948. In both capacities Kindleberger observed and participated indirectly in the 1948 monetary reform in Western Germany. In the 1990s, during his octogenary decade, he revisited the German monetary reform with a fellow participant, economist, and longtime friend, F. Taylor Ostrander. Their collaborative essay became Kindleberger’s effort to reclaim hegemonic stability theory from the scholars who developed it following his works of the 1970s and 1980s.