Showing 141 - 150 of 5709 Items
Date: 2009-07-01
Creator: Anja Forche, P. T. Magee, Anna Selmecki, Judith Berman, Georgiana, May
Access: Open access
- The mechanisms and rates by which genotypic and phenotypic variation is generated in opportunistic, eukaryotic pathogens during growth in hosts are not well understood. We evaluated genomewide genetic and phenotypic evolution in Candida albicans, an opportunistic fungal pathogen of humans, during passage through a mouse host (in vivo) and during propagation in liquid culture (in vitro). We found slower population growth and higher rates of chromosome-level genetic variation in populations passaged in vivo relative to those grown in vitro. Interestingly, the distribution of long-range loss of heterozygosity (LOH) and chromosome rearrangement events across the genome differed for the two growth environments, while rates of short-range LOH were comparable for in vivo and in vitro populations. Further, for the in vivo populations, there was a positive correlation of cells demonstrating genetic alterations and variation in colony growth and morphology. For in vitro populations, no variation in growth phenotypes was detected. Together, our results demonstrate that passage through a living host leads to slower growth and higher rates of genomic and phenotypic variation compared to in vitro populations. Results suggest that the dynamics of population growth and genomewide rearrangement contribute to the maintenance of a commensal and opportunistic life history of C. albicans. Copyright © 2009 by the Genetics Society of America.
Date: 2019-02-05
Creator: W. K. Smith, E. Nelson, J. A. Johnson, S. Polasky, J. C., Milder, J. S. Gerber, P. C. West, S. Siebert, K. A. Brauman
Access: Open access
- Voluntary sustainability standards (VSS) are stakeholder-derived principles with measurable and enforceable criteria to promote sustainable production outcomes. While institutional commitments to use VSS to meet sustainable procurement policies have grown rapidly over the past decade, we still have relatively little understanding of the (i) direct environmental benefits of large-scale VSS adoption; (ii) potential perverse indirect impacts of adoption; and (iii) implementation pathways. Here, we illustrate and address these knowledge gaps using an ecosystem service modeling and scenario analysis of Bonsucro, the leading VSS for sugarcane. We find that global compliance with the Bonsucro environmental standards would reduce current sugarcane production area (−24%), net tonnage (−11%), irrigation water use (−65%), nutrient loading (−34%), and greenhouse gas emissions from cultivation (−51%). Under a scenario of doubled global sugarcane production, Bonsucro adoption would further limit water use and greenhouse gas emissions by preventing sugarcane expansion into water-stressed and high-carbon stock ecosystems. This outcome was achieved via expansion largely on existing agricultural lands. However, displacement of other crops could drive detrimental impacts from indirect land use. We find that over half of the potential direct environmental benefits of Bonsucro standards under the doubling scenario could be achieved by targeting adoption in just 10% of global sugarcane production areas. However, designing policy that generates the most environmentally beneficial Bonsucro adoption pathway requires a better understanding of the economic and social costs of VSS adoption. Finally, we suggest research directions to advance sustainable consumption and production.
Date: 2012-01-01
Creator: William K. Richard, Stephen M. Majercik
Access: Open access
Date: 2019-07-03
Creator: Crystal Hall
Access: Open access
- This article examines the relationship between two fields of study, Italian Studies and Digital Humanities (DH), by documenting projects that employ digital or computational methods in the study of Italian language, literature, history, and the arts. In a complementary fashion, the author outlines the analytical questions of Italian scholars that have potential to advance inquiry in DH. A final section is devoted to contextualizing DH within the practice of Italian Studies at the institutional, program, and department levels by drawing on research of course offerings and a survey circulated in August 2017. The overall finding is that the area of overlap between DH and Italian Studies is intellectually rich, with increasing (yet still sparse) opportunities to develop specialization in this area.
Date: 2010-10-01
Creator: Wayne H. Slade, Emmanuel Boss, Giorgio Dall'olmo, M. Rois Langner, James, Loftin, Michael J. Behrenfeld, Collin Roesler, Toby K. Westberry
Access: Open access
- Optical sensors have distinct advantages when used in ocean observatories, autonomous platforms, and on vessels of opportunity, because of their high-frequency measurements, low power consumption, and the numerous established relationships between optical measurements and biogeochemical variables. However, the issues of biofouling and instrument stability over time remain complicating factors when optical instruments are used over periods longer than several days. Here, a method for obtaining calibration-independent measurements of spectral particle absorption and attenuation is presented. Flow-through optical instrumentation is routinely diverted through a large-surface area 0.2-μm cartridge filter, allowing for the calculation of particle optical properties by differencing temporally adjacent filtered and whole water samples. This approach yields measurements that are independent of drift in instrument calibration. The method has advantages not only for coastally moored deployments, but also for applications in optically clear waters where uncertainties in instrument calibration can be a significant part of the signal measured. The differencing technique is demonstrated using WET Labs (Philomath, Oregon) ac-9 and ac-s multi- and hyperspectral absorption and attenuation meters. For the ac-s sensor, a correction scheme is discussed that utilizes the spectral shape of water absorption in the near-infrared to improve the accuracy of temperature and scattering-corrected spectra. Flow-through particulate absorption measurements are compared with discrete filter-pad measurements and are found to agree well (R = 0.77; rmse = 0.0174 m ). © 2010 American Meteorological Society. 2 -1
Date: 1995-01-01
Creator: Eric Chown, Stephen Kaplan, David Kortenkamp
Access: Open access
- An integrated representation of large-scale space, or cognitive map, colled PLAN, is presented that attempts to address a broader spectrum of issues than has been previously attempted in a single model. Rather than examining way-finding as a process separate from the rest of cognition, one or the fundamental goals of this work is to examine how the wayfinding process is integrated into general cognition. One result of this approach is that the model is "heads-up," or scene-based, because it takes advantage of the properties of the human visual system and, particularly, the visual system's split into two pathways. The emphasis on the human location or "where" system is new to cognitive mapping and is port of an attempt to synthesize prototype theory, associative networks and location together in a connectionist system. Not all of PLAN is new, however. Many of its parts have analogues in one or another preexisting theory. What makes PLAN unique is integrating the various components into a coherent whole, and the capacity of this resulting system to speak to a wide range of constraints. Our approach emphasizes adaptiveness; thus, our focus on such issues as ease of use and efficiency of learning. The result is a model that has a stronger relationship both to the environment, and to the ways that humans interact with it, compared with previous models. The resulting model is examined in some detail and compared to other systems. © 1995.
Date: 2013-03-10
Creator: Yao Tang, Daniel Shapiro, Miaojun Wang, Weiying Zhang
Access: Open access
- We investigate the degree to which corporate governance and ownership affects the innovation performance of firms in China with a particular focus on privately owned small and medium enterprises (SMEs). We hypothesize that (1) board-related governance measures will enhance innovation because they improve monitoring and provide access to necessary resources; (2) ownership concentration initially facilitates innovation because large shareholders are more likely to commit to the long-term nature of innovation, and have the incentive to monitor managers whose time horizon may be shorter; however we argue that these effects weaken as large shareholders becomes entrenched at higher levels of concentration; and (3) hiring an external CEO will enhance innovation both by ensuring professional management of the company, and by alleviating the entrenchment possibilities associated with large shareholders. These hypotheses are tested using a unique sample of 370 mostly private and relatively small Chinese firms in Zhejiang province, for the period 2004 to 2006. The results suggest that for this sample, corporate governance and ownership affect innovation activity when measured by patenting activity, but not when measured by new product sales.
Date: 2008-09-04
Creator: Merton 'Mert' G Henry
Access: Open access
Biographial Note
Merton G. “Mert” Henry was born on February 4, 1926, in Hampden, Maine. He lived there with his parents and helped out at his grandfather’s general store while growing up. He moved to South Portland just before starting high school. He deferred attending Bowdoin College until 1946 in order to serve in the Army, which sent him to the Philippines. He majored in history at Bowdoin and was graduated in the class of 1950. He also earned a law degree from Georgetown Law while working on a military history project at the Pentagon during the Korean War. A long-time leader in the Maine Republican Party, he worked for Senator Fredreick G. Payne of Maine and ran his unsuccessful 1958 reelection campaign, losing to Ed Muskie. Since then he has worked at the same law firm, currently under the name of Jensen Baird Gardner & Henry, in Portland, Maine, where he worked with George Mitchell for twelve years between 1965 and 1977.
Summary
Interview includes discussion of: the Hampden, Maine community; Armed Services; Bowdoin College and law school in Washington D.C; involvement in Senator Frederick Payne’s campaigns, and Senator Margaret Chase Smith’s campaigns; meeting George Mitchell at Jenson Baird law firm; Mitchell’s campaign for governor in 1974; professional and personal relationship between Henry and Mitchell; advice to Mitchell about accepting his Senate appointment; U.S. Senate campaign (1982); Mitchell’s success as a senator; and changes in politics and campaigning.
Date: 2010-01-21
Creator: Michael 'Mike' M Hastings
Access: Open access
Biographial Note
Michael M. Hastings, a native of Morrill, Maine, graduated from Tilton School (NH) in 1968 and Bowdoin College in 1972. Following a year of graduate study in Public & International Affairs at George Washington University, he worked for seven years as a foreign and defense policy aide to Senator William S. Cohen (1973-1980) and for four years for Senator George J. Mitchell (1980-1984). In October 1984, he joined the international staff of Catholic Relief Services (CRS) and moved to Africa. Over a span of eight years, he worked as a CRS development administrator in Kenya, Tanzania, Togo and The Gambia. During the same period, he assisted in the provision of emergency food for people displaced by civil wars in the Southern Sudan and Liberia. In 1992, he returned to Maine to direct a “center for excellence,” focusing on aquaculture and economic development. Since 2004, he has worked for the University of Maine as its director of Research and Sponsored Programs. Between 1992 and 2008, he also served on several civic boards and institutions including the Maine Fishermen’s Forum, the Maine Oil Spill Advisory Committee, the Maine Indian Tribal State Commission, the Down East Institute, and the Maine Sea Grant Policy Advisory Committee. Between 1996 and 2001, he was elected three times to be a member of the Town Council of Hampden, Maine, where he resides with his wife, a middle school teacher.
Summary
Interview includes discussion of: his transition from Cohen’s staff to Mitchell’s staff; Cohen’s feelings about Hastings’s move to Mitchell’s office; state and national issues; Kahlil Gibran; Cohen’s and Mitchell’s leadership styles with their office staff; the staff atmosphere around Mitchell’s 1982 election; the Mikulski Commission; the 1982 election; Mitchell’s staff, including Jane O’Connor, Regina Sullivan, and Gayle Cory; relationship between the Mitchell staff and the Cohen staff; Men of Zeal and the Iran-Contra scandal; Pat Cadell; Jim Tierney; Mitchell and Arab American groups; John Linnehan; anecdote about placing a large photo of George Mitchell in his Maine campaign office during the 1982 campaign; driving Muskie around; and Margaret Chase Smith coming back to Washington to celebrate her birthday with Mitchell.