Showing 3401 - 3450 of 5831 Items

Date: 1988-01-01

Access: Open access

Exhibition held at Bowdoin College Museum of Art, January 29 - March 24, 1988

Date: 2019-05-01

Creator: Brandon Morande

Access: Open access

On any given night, thousands of individuals sleep on the streets of the Ciudad Autónoma de Buenos Aires. Without secure housing, people in situación de calle (experiencing homelessness) suffer elevated rates of physical trauma, transmissible and chronic diseases, and symptoms of depression. Nevertheless, two-thirds of this population do not receive annual health consultations, with the majority solely accessing the emergency department when their conditions severely worsen. This study finds that municipal services and, to a lesser extent, the public health system render individuals responsible for housing insecurity by adopting a neoliberal subjectivity of homo economicus, medicalizing poverty as a symptom of psychosocial illness potentially curable through economic and social rehabilitation. Those who do not conform with such pathologization or other employment-based demands confront heightened criminalization and exclusion from care services. As an alternative response, this project investigates the actions of civil society networks, which employ a contrary notion of homo politicus, reimagining care as a collective right and site of political mobilization. This thesis draws upon interviews with people experiencing or at risk of homelessness, members of civil society organizations, public health providers, and municipal social workers, as well as observations from street-outreach.

Date: 1992-01-01

Access: Open access

Date: 2014-01-01

Creator: Allen Wells, Natalia Sanz González, (translator)

Access: Open access

Setecientos cincuenta refugiados judíos dejaron la Alemania nazi y fundaron la colonia agrícola de Sosúa en la República Dominicana, que en ese momento estaba bajo el régimen de uno de los dictadores más represivos de Latinoamérica, el general Rafael Trujillo. En este libro, Allen Wells, hijo de uno de los colonos de Sosúa, cuenta la historia del general Trujillo, Franklin Delano Roosevelt y los afortunados pioneros que fundaron, en la costa norte de la isla, una exitosa cooperativa de productos lácteos de propiedad de los mismos empleados. ¿Por qué el dictador admitió a esos desesperados refugiados cuando muy pocas naciones aceptaron a los que escapaban del nazismo? Ansioso de mitigar las críticas internacionales después de que su Ejército masacrara varios miles de haitianos desarmados, Trujillo mandó a sus representantes a una conferencia sobre los refugiados del nazismo realizada en Évian, Francia, en 1938. Propuesta por Roosevelt para desviar las críticas a las políticas restrictivas de inmigración de su Gobierno, la Conferencia de Évian resultó un completo fracaso. La República Dominicana fue la única nación que aceptó abrir sus puertas; el oportunista Trujillo buscaba “blanquear” la población dominicana, recibiendo refugiados judíos, quienes en Europa eran ellos mismos sujeto de desprecio racista. Debido a que los Estados Unidos no admitieron números significativos de refugiados judíos, alentaron a Latinoamérica a aceptarlos. Esta propuesta, sumada a la preocupación mayor de Roosevelt de luchar contra el nazismo, fortaleció las relaciones estadounidenses con las dictaduras latinoamericanas en las décadas que vendrían.

Date: 1907-01-01

Access: Open access

Date: 1991-01-01

Creator: M. Alfaro, M. Conger, K. Hodges, A. Levy, R., Kochar, L. Kuklinski

Access: Open access

Date: 1969-01-01

Creator: Richard V. West

Access: Open access

Catalogue of an exhibition held at Bowdoin College Museum of Art.

Date: 2021-01-01

Creator: José Edwards, Stephen Meardon

Access: Open access

In 2018, Clarivate Analytics, publisher of the Web of Science Journal Citation Reports (JCR), suppressed publication of the 2017 Journal Impact Factor (JIF) for three of the four journals that it then indexed in the academic field of history of economics. Clarivate judged one of the journals, History of Economic Ideas (HEI), to be the “donor” of citations that distorted the impact factors of the European Journal of the History of Economic Thought (EJHET) and the Journal of the History of Economic Thought (JHET). The other journal, History of Political Economy (HOPE), was not included in that judgment. Our purpose is to define the JIF, summarize the controversy that gave rise to this symposium, and discuss methodologically and historically some of the problems with the use of citation indexes in general and the JIF in particular. We show how these problems pertain differently to the scholarly field of the history of economics than to economics in general. In so doing we also introduce the following five articles of this symposium.

Date: 2020-05-01

Creator: Erika Nyhus, William A. Engel, Tomas Donatelli Pitfield, Isabella M.W. Vakkur

Access: Open access

Although there has been recent interest in how mindfulness meditation can affect episodic memory as well as brain structure and function, no study has examined the behavioral and neural effects of mindfulness meditation on episodic memory. Here we present a protocol that combines mindfulness meditation training, an episodic memory task, and EEG to examine how mindfulness meditation changes behavioral performance and the neural correlates of episodic memory. Subjects in a mindfulness meditation experimental group were compared to a waitlist control group. Subjects in the mindfulness meditation experimental group spent four weeks training and practicing mindfulness meditation. Mindfulness was measured before and after training using the Five Facet Mindfulness Questionnaire (FFMQ). Episodic memory was measured before and after training using a source recognition task. During the retrieval phase of the source recognition task, EEG was recorded. The results showed that mindfulness, source recognition behavioral performance, and EEG theta power in right frontal and left parietal channels increased following mindfulness meditation training. In addition, increases in mindfulness correlated with increases in theta power in right frontal channels. Therefore, results obtained from combining mindfulness meditation training, an episodic memory task, and EEG reveal the behavioral and neural effects of mindfulness meditation on episodic memory.

Date: 1910-01-01

Access: Open access

Date: 2016-04-01

Creator: Bruce D. Kohorn, Divya Hoon, Benjamin B. Minkoff, Michael R. Sussman, Susan L., Kohorn

Access: Open access

The wall-associated kinases (WAKs)1 are receptor protein kinases that bind to long polymers of cross-linked pectin in the cell wall. These plasma-membrane-associated protein kinases also bind soluble pectin fragments called oligo-galacturonides (OGs) released from the wall after pathogen attack and damage. WAKs are required for cell expansion during development but bind water soluble OGs generated from walls with a higher affinity than the wall-associated polysaccharides. OGs activate a WAKdependent, distinct stress-like response pathway to help plants resist pathogen attack. In this report, a quantitative mass-spectrometric-based phosphoproteomic analysis was used to identify Arabidopsis cellular events rapidly induced by OGs in planta. Using N14/ N15 isotopic in vivo metabolic labeling, we screened 1,000 phosphoproteins for rapid OG-induced changes and found 50 proteins with increased phosphorylation, while there were none that decreased significantly. Seven of the phosphosites within these proteins overlap with those altered by another signaling molecule plants use to indicate the presence of pathogens (the bacterial "elicitor" peptide Flg22), indicating distinct but overlapping pathways activated by these two types of chemicals. Genetic analysis of genes encoding 10 OG-specific and two Flg22/OG-induced phosphoproteins reveals that null mutations in eight proteins compromise the OG response. These phosphorylated proteins with genetic evidence supporting their role in the OG response include two cytoplasmic kinases, two membrane-associated scaffold proteins, a phospholipase C, a CDPK, an unknown cadmium response protein, and a motor protein. Null mutants in two proteins, the putative scaffold protein REM1.3, and a cytoplasmic receptor like kinase ROG2, enhance and suppress, respectively, a dominant WAK allele. Altogether, the results of these chemical and genetic experiments reveal the identity of several phosphorylated proteins involved in the kinase/ phosphatase-mediated signaling pathway initiated by cell wall changes.

Date: 2016-01-01

Creator: Bruce D. Kohorn

Access: Open access

The pectin matrix of the angiosperm cell wall is regulated in both synthesis and modification and greatly influences the direction and extent of cell growth. Pathogens, herbivory and mechanical stresses all influence this pectin matrix and consequently plant form and function. The cell wall-associated kinases (WAKs) bind to pectin and regulate cell expansion or stress responses depending upon the state of the pectin. This review explores the WAKs in the context of cell wall biology and signal transduction pathways.

Date: 2019-09-04

Creator: Erika Nyhus, William Andrew Engel, Tomas Donatelli Pitfield, Isabella Marie Wang Vakkur

Access: Open access

Mindfulness meditation has been shown to improve episodic memory and increase theta oscillations which are known to play a role in episodic memory retrieval. The present study examined the effect of mindfulness meditation on episodic memory retrieval and theta oscillations. Using a longitudinal design, subjects in the mindfulness meditation experimental group who underwent 4 weeks of mindfulness meditation training and practice were compared to a waitlist control group. During the pre-training and post-training experimental sessions, subjects completed the Five Facet Mindfulness Questionnaire (FFMQ) and studied adjectives and either imagined a scene (Place Task) or judged its pleasantness (Pleasant Task). During the recognition test, subjects decided which task was performed with each word (“Old Place Task” or “Old Pleasant Task”) or “New.” FFMQ scores and source discrimination were greater post-training than pre-training in the mindfulness meditation experimental group. Electroencephalography (EEG) results revealed that for the mindfulness meditation experimental group theta power was greater post-training than pre-training in right frontal and left parietal channels and changes in FFMQ scores correlated with changes in theta oscillations in right frontal channels (n = 20). The present results suggest that mindfulness meditation increases source memory retrieval and theta oscillations in a fronto-parietal network.

Date: 2021-06-15

Creator: Rachel J. Beane, Eric M.D. Baer, Rowan Lockwood, R. Heather Macdonald, John, R., McDaris, Vernon R. Morris, I. Joshua Villalobos, Lisa D. White

Access: Open access

Date: 2019-08-01

Creator: Lea Takács, Filip Smolík, Samuel Putnam

Access: Open access

Background Previous studies of relations between parenting self-concepts, parental adjustment and child temperament have been ambiguous regarding the direction of influence; and have rarely followed families from pregnancy through the first year of life. The current study examines change and stability in maternal depressive symptoms, parenting competences and child temperament through the perinatal period until nine months postpartum. Methods Czech mothers (N = 282) participated at three time points: the third trimester of pregnancy (Time 1), six weeks (Time 2) and nine months postpartum (Time 3). Questionnaire data concerned depressive symptoms (T1, T2, T3), maternal parenting self-esteem (T1, T2) and sense of competence (T3), and child temperament (T2, T3). A path model was used to examine concurrent and longitudinal relations between these variables. Results The analyses indicated longitudinal stability of all constructs, as well as concurrent relations between them. Longitudinal relations supported child-to-parent, rather than parent-to-child, effects: child difficult temperament predicted decreases in perceived maternal parenting competences, but maternal variables did not predict change in infant temperament. In addition, we observed weak mutual relations between maternal depression levels and parenting competences, such that maternal depression diminished perceived parenting competences that in turn contributed to higher levels of depression. Conclusion Mothers’ confidence in their ability to parent is influenced by their experience with a difficult infant and by their depressive symptoms during the child’s first year of life. Depressive symptoms are, in turn, aggravated by mothers’ low perceived competences in the parenting role.

Date: 2014-01-01

Creator: Xinyang Bing, Teresa Z. Rzezniczak, Jack R. Bateman, Thomas J.S. Merritt

Access: Open access

Transvection, a chromosome pairing-dependent form of trans-based gene regulation, is potentially widespread in the Drosophila melanogaster genome and varies across cell types and within tissues in D. melanogaster, characteristics of a complex trait. Here, we demonstrate that the trans-interactions at the Malic enzyme (Men) locus are, in fact, transvection as classically defined and are plastic with respect to both genetic background and environment. Using chromosomal inversions, we show that trans-interactions at the Men locus are eliminated by changes in chromosomal architecture that presumably disrupt somatic pairing. We further show that the magnitude of transvection at the Men locus is modified by both genetic background and environment (temperature), demonstrating that transvection is a plastic phenotype. Our results suggest that transvection effects in D. melanogaster are shaped by a dynamic interplay between environment and genetic background. Interestingly, we find that cis-based regulation of the Men gene is more robust to genetic background and environment than trans-based. Finally, we begin to uncover the nonlocal factors that may contribute to variation in transvection overall, implicating Abd-B in the regulation of Men in cis and in trans in an allele-specific and tissue-specific manner, driven by differences in expression of the two genes across genetic backgrounds and environmental conditions.

Date: 1901-01-01

Access: Open access

Date: 2018-05-04

Creator: Maria Tysiachniouk, Laura A. Henry, Machiel Lamers, Jan P.M. van Tatenhove

Access: Open access

How can indigenous communities in illiberal regimes benefit from oil production? This paper compares the experience of two indigenous peoples in the Russian Arctic, the Nenets and the Komi-Izhemtsi, in their quest for environmental protection and the development of benefit-sharing arrangements with Lukoil, a Russian oil company. The Nenets people, recognized by the Russian state as indigenous, are marginalized political actors who identified a route to receiving compensation for loss of land and damage to the environment as well as economic benefits under the auspices of Russian law and Lukoil’s corporate policies. In contrast, the Komi-Izhemtsi, despite indigenous status in global institutions including the United Nations and the Arctic Council, are unrecognized as indigenous domestically and initially received no compensation. Their path to benefit sharing was more challenging as they partnered with local nongovernmental organizations and global environmentalists to pressure Lukoil to sign a benefit-sharing agreement. Ultimately, the comparison illustrates how transnational partnerships can empower indigenous people to gain benefits from natural resource exploitation even in illiberal political systems.

Date: 2018-03-01

Creator: Maria Tysiachniouk, Laura A. Henry, Machiel Lamers, Jan P.M. van Tatenhove

Access: Open access

How can the interests of extractive industries and indigenous communities in the Arctic be balanced through benefit sharing policies? This paper analyses how the international oil consortia of Sakhalin Energy and Exxon Neftegaz Limited (ENL) on Sakhalin Island in Russia have introduced benefit sharing through tripartite partnerships. We demonstrate that the procedural and distributional equity of benefit sharing depend on corporate policies, global standards, pressure from international financial institutions, and local social movements connected in a governance generating network. Sakhalin Energy was profoundly influenced by international financial institutions’ global rules related to environmental and indigenous people's interests. The benefit sharing arrangement that evolved under these influences resulted in enhanced procedural equity for indigenous people, but has not prevented conflict with and within communities. In contrast, ENL was not significantly influenced by international financial institutions. Its more flexible and limited benefit sharing arrangement was shaped predominantly by global corporate policies, pressure from the regional government and the influence of Sakhalin Energy's model. The paper closes with policy recommendations on benefit sharing arrangements between extractive industries and indigenous communities across Arctic states that could be further developed by the Arctic Council Sustainable Development Working Group.

Date: 2021-12-01

Creator: Laura Howells, Laura A. Henry

Access: Open access

Digital authoritarianism threatens the privacy and rights of Internet users worldwide, yet scholarship on this topic remains limited in analytical power and case selection. In this article, we introduce a comprehensive analytical framework to the field of Internet governance and apply it first, briefly, to the well-known case of China and then, in more depth, to the still-understudied Russian case. We identify the extent and relative centralization of Internet governance as well as proactive versus reactive approaches to governance as notable differences between the cases, highlighting variation among digital authoritarians’ governance strategies. We conclude that Russia’s Internet governance model is less comprehensive and consistent than China’s, but its components may be more easily exported to other political systems. We then consider whether recent changes to Russia’s Internet governance suggest that it could converge with the Chinese model over time.

Date: 2014-04-08

Creator: Van N. Tra, Danielle H. Dube

Access: Open access

A substantial obstacle to the existing treatment of bacterial diseases is the lack of specific probes that can be used to diagnose and treat pathogenic bacteria in a selective manner while leaving the microbiome largely intact. To tackle this problem, there is an urgent need to develop pathogen-specific therapeutics and diagnostics. Here, we describe recent evidence that indicates distinctive glycans found exclusively on pathogenic bacteria could form the basis of targeted therapeutic and diagnostic strategies. In particular, we highlight the use of metabolic oligosaccharide engineering to covalently deliver therapeutics and imaging agents to bacterial glycans. © 2014 The Partner Organisations.

Date: 2014-08-01

Creator: Schuyler Nardelli

Access: Open access

Phytoplankton are the simple single-celled photosynthesizers that live in the ocean and form the base of the food chain. Cell size is a basic proxy for physiological rates as well as ecosystem structure. Thus, cell size can be used in a model framework to track changing environmental conditions that could potentially lead to harmful algal blooms (HABs, aka “red tides”)—events that can be detrimental to human health, marine life, and fisheries. HABs occur when a single algae (phytoplankton) species either grows unconstrained to a concentration such that it becomes toxic or causes low oxygen concentration in the water. In typical estuaries, less dense freshwater flows towards the ocean, and denser salty seawater flows into the estuary in the subsurface. However, Harpswell Sound is a reverse estuary that receives its freshwater input at its mouth from the upstream Kennebec River. This yields upstream surface low salinity flow and downstream deep high salinity flow. This rare dynamic allows phytoplankton located in the surface of seawater to be retained in the sound in conditions conducive to high growth and HABs, and can be used as a warning for conditions throughout the Gulf of Maine. To study the temporal and spatial dynamics of phytoplankton in the sound, we used the LISST-100, which uses light scattering properties to collect continuous in-situ water column observations of particle concentrations and size distributions. Although the LISST-100 was built to measure sediment size with a spherical shape, studies have been conducted that show it can accurately describe a diverse range of phytoplankton shapes and sizes, provided the population has sufficient size differences and is fairly concentrated, conditions found in Harpswell Sound. Weekly profiles of the water column were collected at the Bowdoin Buoy from 5/21/14-6/18/14, as well as a 20-day continuous time series collected at Bowdoin’s Coastal Studies Center dock from 5/30/14-6/18/14 along with supplementary oceanographic data. We determined that semi-diurnal tidal fluctuations are sufficient to move water masses past the buoy and dock with each tide, thereby connecting them. Phytoplankton were found to be in the 3-50 micron size range, with a peak diameter of approximately 7 microns. Additionally, three independent phytoplankton blooms were observed over the course of the 20-day time series as different water masses flowed through the sound. They were sourced in the oceanic water masses found under the freshened surface layer. Over the five-week period the populations gradually surfaced with their water mass as the overlying freshwater dissipated in the absence of rainfall. The LISST-100 served as a useful tool for determining phytoplankton distribution and dynamics within Harpswell Sound, and with further research there is great potential to continue to increase proficiency with the instrument in order to better understand phytoplankton dynamics and harmful algal blooms. Final Report of research funded by the Rusack Coastal Studies Fellowship.

Date: 2017-09-01

Creator: G. Serrato Marks, M. LaVigne, T. M. Hill, W. Sauthoff, T. P., Guilderson, E. B. Roark, R. B. Dunbar, T. J. Horner

Access: Open access

Trace elemental ratios preserved in the calcitic skeleton of bamboo corals have been shown to serve as archives of past ocean conditions. The concentration of dissolved barium (Ba ), a bioactive nutrientlike element, is linked to biogeochemical processes such as the cycling and export of nutrients. Recent work has calibrated bamboo coral Ba/Ca, a new Ba proxy, using corals spanning the oxygen minimum zone beneath the California Current System. However, it was previously unclear whether Ba/Ca records were internally reproducible. Here we investigate the accuracy of using laser ablation inductively coupled plasma mass spectrometry for Ba/Ca analyses and test the internal reproducibility of Ba/Ca among replicate radial transects in the calcite of nine bamboo corals collected from the Gulf of Alaska (643–720 m) and the California margin (870–2054 m). Data from replicate Ba/Ca transects were aligned using visible growth bands to account for nonconcentric growth; smoothed data were reproducible within ~4% for eight corals (n = 3 radii/coral). This intracoral reproducibility further validates using bamboo coral Ba/Ca for Ba reconstructions. Sections of the Ba/Ca records that were potentially influenced by noncarbonate bound Ba phases occurred in regions where elevated Mg/Ca or Pb/Ca and coincided with anomalous regions on photomicrographs. After removing these regions of the records, increased Ba/Ca variability was evident in corals between ~800 and 1500 m. These findings support additional proxy validation to understand Ba variability on interannual timescales, which could lead to new insights into deep sea biogeochemistry over the past several centuries. SW SW coral coral SW coral SW

Date: 2006-07-25

Creator: Jason Hill, Erik Nelson, David Tilman, Stephen Polasky, Douglas, Tiffany

Access: Open access

Negative environmental consequences of fossil fuels and concerns about petroleum supplies have spurred the search for renewable transportation biofuels. To be a viable alternative, a biofuel should provide a net energy gain, have environmental benefits, be economically competitive, and be producible in large quantities without reducing food supplies. We use these criteria to evaluate, through life-cycle accounting, ethanol from corn grain and biodiesel from soybeans. Ethanol yields 25% more energy than the energy invested in its production, whereas biodiesel yields 93% more. Compared with ethanol, biodiesel releases just 1.0%, 8.3%, and 13% of the agricultural nitrogen, phosphorus, and pesticide pollutants, respectively, per net energy gain. Relative to the fossil fuels they displace, greenhouse gas emissions are reduced 12% by the production and combustion of ethanol and 41% by biodiesel. Biodiesel also releases less air pollutants per net energy gain than ethanol. These advantages of biodiesel over ethanol come from lower agricultural inputs and more efficient conversion of feedstocks to fuel. Neither biofuel can replace much petroleum without impacting food supplies. Even dedicating all U.S. corn and soybean production to biofuels would meet only 12% of gasoline demand and 6% of diesel demand. Until recent increases in petroleum prices, high production costs made biofuels unprofitable without subsidies. Biodiesel provides sufficient environmental advantages to merit subsidy. Transportation biofuels such as synfuel hydrocarbons or cellulosic ethanol, if produced from low-input biomass grown on agriculturally marginal land or from waste biomass, could provide much greater supplies and environmental benefits than food-based biofuels. © 2006 by The National Academy of Sciences of the USA.

Date: 2008-07-01

Creator: Samuel P. Putnam, Cynthia A. Stifter

Access: Open access

Through her theoretical and empirical work, Mary Rothbart has had a profound impact on the scientific understanding of infant and child temperament. This special issue honors her contributions through the presentations of original, contemporary studies relevant to three primary themes in Rothbart's conceptual approach: the expansive scope and empirically-derived structure of temperament, the importance of considering developmental change, and the interplay of reactive and regulatory processes. In addition to summarizing these themes, this introductory article acknowledges the ways Mary has spurred progress in the field through methodological advances, institutional service, and pedagogy. Copyright © 2008 John Wiley & Sons, Ltd.

Date: 2017-06-08

Creator: Henriette Elvang, Callum R.T. Jones, Stephen G. Naculich

Access: Open access

Extensions of the photon and graviton soft theorems are derived in 4D local effective field theories with massless particles of arbitrary spin. We prove that effective operators can result in new terms in the soft theorems at subleading order for photons and subsubleading order for gravitons. The new soft terms are unique, and we provide a complete classification of all local operators responsible for such modifications. We show that no local operators can modify the subleading soft graviton theorem. The soft limits are taken in a manifestly on-locus manner using a complex double deformation of the external momenta. In addition to the new soft theorems, the resulting master formula yields consistency conditions, such as the conservation of electric charge, the Einstein equivalence principle, supergravity Ward identities, and that particles with spin greater than two cannot couple to those with spin less than or equal to two.

Date: 2009-01-01

Access: Open access

A family guide and activity book to accompany the joint exhibition of the same title held at the Bowdoin College Museum of Art, Feb. 3-May 10, 2009 and the Colby College Museum of Art, Jan.22-Mar. 8, 2009. Concept and initial design by Bowdoin College students Gea Ermotti, Anna Kosovsky, Erica McLeod, and Eleanor Meyer. Production and final design by Colby College student Alyssa Lee.

Date: 1911-01-01

Access: Open access

Date: 1968-01-01

Creator: Christopher Huntington

Access: Open access

"An exhibition made possible by the Maine State Commission on the Arts and the Humanities, together with the exhibiting institutions ... Coordinator of the exhibition - Christopher Huntington." Catalogue of an exhibition held at the Colby College Art Museum Aug. 14-Sept. 22, 1968; Bowdoin College Museum of Art Nov.1-25, 1968.

Date: 1986-01-01

Creator: Yvonne Jacquette

Access: Open access

Catalogue of an exhibition held Apr. 5-May 3, 1986, at Brooke Alexander, New York, and June 27-Aug. 24, 1986, at Bowdoin College Museum of Art, Brunswick, Maine

Date: 2004-06-01

Creator: Anja Forche, P. T. Magee, B. B. Magee, Georgiana May

Access: Open access

Single-nucleotide polymorphisms (SNPs) are essential tools for studying a variety of organismal properties and processes, such as recombination, chromosomal dynamics, and genome rearrangement. This paper describes the development of a genome-wide SNP map for Candida albicans to study mitotic recombination and chromosome loss. C. albicans is a diploid yeast which propagates primarily by clonal mitotic division. It is the leading fungal pathogen that causes infections in humans, ranging from mild superficial lesions in healthy individuals to severe, life-threatening diseases in patients with suppressed immune systems. The SNP map contains 150 marker sequences comprising 561 SNPs and 9 insertions-deletions. Of the 561 SNPs, 437 were transition events while 126 were transversion events, yielding a transition-to-transversion ratio of 3:1, as expected for a neutral accumulation of mutations. The average SNP frequency for our data set was 1 SNP per 83 bp. The map has one marker placed every 111 kb, on average, across the 16-Mb genome. For marker sequences located partially or completely within coding regions, most contained one or more nonsynonymous substitutions. Using the SNP markers, we identified a loss of heterozygosity over large chromosomal fragments in strains of C. albicans that are frequently used for gene manipulation experiments. The SNP map will be useful for understanding the role of heterozygosity and genome rearrangement in the response of C. albicans to host environments.

Date: 1894-01-01

Access: Open access

Date: 1932-01-01

Access: Open access

Date: 2014-08-01

Creator: Sabine Y Berzins

Access: Open access

Eelgrass (Zostera marina) is a perennial seagrass that is widely distributed among the shallow subtidal and intertidal Atlantic coastline of the United States and Canada. A highly productive keystone species, eelgrass helps maintain healthy estuarine and ecosystem functions by stabilizing sediments, regulating water flow, absorbing nutrients, and providing critical habitat for animals including commercially important species like soft-shell clams, blue mussels, and migrating waterfowl. Loss of eelgrass beds can therefore result in degraded water quality, shoreline erosion, and reduced fish and wildlife populations. Historically, the Maine coast supported extensive eelgrass beds. However, between 2010 and 2013, eelgrass distribution in Casco Bay declined in area by over 55%. This decline in eelgrass distribution coincides with a regional population explosion of green crabs (Carcinus maenas), an invasive species that physically disturbs eelgrass while foraging for prey. This summer, I collaborated with several Casco Bay Eelgrass Partners including individuals from the Fish and Wildlife Service, Maine Department of Environmental Protection, and the Friends of Casco Bay. Led by U.S. Geological Survey biologist Dr. Hilary Neckles, this project identifies factors that make eelgrass more or less resilient to invasion by green crabs. In June, we established permanent eelgrass survey transects at five locations spanning eastern Casco Bay. Where possible, two transects were established in different types of sediment (fine or coarse/sandy). Most of the eelgrass loss observed over the past decade has been in fine sediments. The question remains; is eelgrass in coarse sediments prone to similar levels of damage? In addition to differences in substrate type, each site also exhibited varying degrees of eelgrass density, shoot height, green crab density and population structure, and other environmental stressors including light availability, temperature, nutrient availability, and natural physical disturbance. I made biweekly measurements of green crab densities at one site, Widgeon Cove in Harpswell. Crap trapping indicated few green crabs occurred near the Widgeon Cove transect, but traps at the other four Casco Bay sites collected as many as 300 crabs within a 24-hour period. Final measurements in the eelgrass transects will be taken in September and data collection will be completed in October. Data gathered this summer will provide information to help move forward with a plan to protect and potentially restore eelgrass in Casco Bay. Additionally, I identified patches of eelgrass in the Kennebec Estuary that might be viable sites for replanting next summer. I hope to continue working on this project next year, thinking about ways to restore eelgrass to the system while identifying ways to increase trapping pressure on green crabs such that their numbers might be reduced. Final Report of research funded by the Rusack Coastal Studies fellowship.

Date: 1999-01-01

Creator: Eric Chown

Access: Open access

This article examines the relationship between environmental and cognitive structure. One of the key tasks for any agent interacting in the real world is the management of uncertainty; because of this the cognitive structures which interact with real environments, such as would be used in navigation, must effectively cope with the uncertainty inherent in a constantly changing world. Despite this uncertainty, however, real environments usually afford structure that can be effectively exploited by organisms. The article examines environmental characteristics and structures that enable humans to survive and thrive in a wide range of real environments. The relationship between these characteristics and structures, uncertainty, and cognitive structure is explored in the context of PLAN, a proposed model of human cognitive mapping, and R-PLAN, a version of PLAN that has been instantiated on an actual mobile robot. An examination of these models helps to provide insight into environmental characteristics which impact human performance on tasks which require interaction with the world. Copyright 1999 International Society for Adaptive Behavior.

Date: 2019-10-02

Creator: R. Heather Macdonald, Rachel J. Beane, Eric M.D. Baer, Pamela L. Eddy, Norlene R., Emerson, Jan Hodder, Ellen R. Iverson, John R. McDaris, Kristin O’Connell, Carol J. Ormand

Access: Open access

Faculty play an important role in attracting students to the geosciences, helping them to thrive in geoscience programs, and preparing them for careers. Thus, faculty have the responsibility to work toward broadening participation in the geosciences by implementing equitable and inclusive practices in their teaching and their programs. Faculty professional development that promotes diversity and inclusion is one way to move evidence-based practices into wider use. The adoption of these practices may be accelerated through a professional development diffusion model that amplifies the impacts through the work of faculty change agents. An example of this approach is the SAGE 2YC professional development program, in which faculty change agents learn and practice strategies during workshop sessions, implement changes in their own teaching, and then work in teams to lead workshops in their region under the auspices of the national program. Although this example focuses on two-year colleges, the model is applicable to faculty professional development more broadly. The success of the model is due in large part to a suite of leader-developed workshop sessions and curated resources that change agent teams may select and adapt for the regional workshops they lead. Furthermore, change agents are trusted colleagues, which makes adoption of the evidence-based practices by regional workshop participants more likely. Increased adoption of a change agent approach to faculty development will support the creation and sharing of additional resources, leading to wider diffusion and implementation of inclusive teaching practices.

Date: 2021-01-01

Creator: Anonymous

Access: Open access

This is a response to the Documenting Bowdoin & COVID-19 Reflections Questionnaire. The questionnaire was created in March 2021 by staff of Bowdoin's George J. Mitchell Department of Special Collections & Archives. The author is from the class of 2022.

Date: 2019-02-01

Creator: Stephen G. Warren, Collin S. Roesler, Richard E. Brandt, Mark Curran

Access: Open access

Ice crystals form in supercooled seawater beneath several Antarctic ice shelves; as they rise to the ice-shelf base they scavenge particles from the water and incorporate them into the growing basal ice. The resulting marine ice can be ~100 m thick; it differs from sea ice in that it is clear, desalinated, and bubble-free. Icebergs of marine ice vary in color from blue to green, depending on the nature and abundance of foreign constituents in the seawater that became trapped in the ice as it grew. A red or yellow material (i.e., one that absorbs blue light), in combination with the blue of ice, can shift the wavelength of minimum absorption to green. Previously, dissolved organic carbon (DOC) had been proposed to be responsible for the green color. Subsequent measurements of low DOC values in green icebergs, together with the recent finding of large concentrations of iron in marine ice from the Amery Ice Shelf, suggest that the color of green icebergs is caused more by iron-oxide minerals than by DOC. These icebergs travel great distances from their origin; when they melt they can deliver iron as a nutrient to the Southern Ocean.

Date: 2010-01-01

Creator: Diana K. Tuite, Linda J. Docherty

Access: Open access

Date: 2010-12-01

Creator: Erik Nelson, Heather Sander, Peter Hawthorne, Marc Conte, Driss, Ennaanay, Stacie Wolny, Steven Manson, Stephen Polasky

Access: Open access

Background: As the global human population grows and its consumption patterns change, additional land will be needed for living space and agricultural production. A critical question facing global society is how to meet growing human demands for living space, food, fuel, and other materials while sustaining ecosystem services and biodiversity [1]. Methodology/Principal Findings: We spatially allocate two scenarios of 2000 to 2015 global areal change in urban land and cropland at the grid cell-level and measure the impact of this change on the provision of ecosystem services and biodiversity. The models and techniques used to spatially allocate land-use/land-cover (LULC) change and evaluate its impact on ecosystems are relatively simple and transparent [2]. The difference in the magnitude and pattern of cropland expansion across the two scenarios engenders different tradeoffs among crop production, provision of species habitat, and other important ecosystem services such as biomass carbon storage. For example, in one scenario, 5.2 grams of carbon stored in biomass is released for every additional calorie of crop produced across the globe; under the other scenario this tradeoff rate is 13.7. By comparing scenarios and their impacts we can begin to identify the global pattern of cropland and irrigation development that is significant enough to meet future food needs but has less of an impact on ecosystem service and habitat provision. Conclusions/Significance: Urban area and croplands will expand in the future to meet human needs for living space, livelihoods, and food. In order to jointly provide desired levels of urban land, food production, and ecosystem service and species habitat provision the global society will have to become much more strategic in its allocation of intensively managed land uses. Here we illustrate a method for quickly and transparently evaluating the performance of potential global futures.

Date: 2008-05-01

Creator: Anja Forche, Kevin Alby, Dana Schaefer, Alexander D. Johnson, Judith, Berman, Richard J. Bennett

Access: Open access

Candida albicans has an elaborate, yet efficient, mating system that promotes conjugation between diploid a and α strains. The product of mating is a tetraploid a/α cell that must undergo a reductional division to return to the diploid state. Despite the presence of several "meiosis-specific" genes in the C. albicans genome, a meiotic program has not been observed. Instead, tetraploid products of mating can be induced to undergo efficient, random chromosome loss, often producing strains that are diploid, or close to diploid, in ploidy. Using SNP and comparative genome hybridization arrays we have now analyzed the genotypes of products from the C. albicans parasexual cycle. We show that the parasexual cycle generates progeny strains with shuffled combinations of the eight C. albicans chromosomes. In addition, several isolates had undergone extensive genetic recombination between homologous chromosomes, including multiple gene conversion events. Progeny strains exhibited altered colony morphologies on laboratory media, demonstrating that the parasexual cycle generates phenotypic variants of C. albicans. In several fungi, including Saccharomyces cerevisiae and Schizosaccharomyces pombe, the conserved Spo11 protein is integral to meiotic recombination, where it is required for the formation of DNA double-strand breaks. We show that deletion of SPO11 prevented genetic recombination between homologous chromosomes during the C. albicans parasexual cycle. These findings suggest that at least one meiosis-specific gene has been re-programmed to mediate genetic recombination during the alternative parasexual life cycle of C. albicans. We discuss, in light of the long association of C. albicans with warm-blooded animals, the potential advantages of a parasexual cycle over a conventional sexual cycle. © 2008 Forche et al.

Date: 2019-01-01

Creator: Jack R. Bateman, David J. Anderson

Access: Open access

Date: 1903-01-01

Access: Open access

Date: 2014-01-01

Creator: Jarrod Olson, Daniel F. Stone

Access: Open access

U.S. college football’s traditional bowl system, and lack of a postseason play-off tournament, has been controversial for years. The conventional wisdom is that a play-off would be a more fair way to determine the national champion, and more fun for fans to watch. The colleges finally agreed to begin a play-off in the 2014-2015 season, but with just four teams, and speculation continues that more teams will be added soon. A subtle downside to adding play-off teams is that it reduces the significance of regular season games.We use the framework of Ely, Frankel, and Kamenica (in press) to directly estimate the utility fans would get from this significance, that is, utility from suspense, under a range of play-off scenarios. Our results consistently indicate that play-off expansion causes a loss in regular season suspense utility greater than the gain in the postseason, implying the traditional bowl system (two team play-off) is suspense-optimal. We analyze and discuss implications for TV viewership and other contexts.

Date: 1889-01-01

Access: Open access

Date: 2002-12-22

Creator: Amy S. Johnson, Olaf Ellers, Jim Lemire, Melissa Minor, Holly A., Leddy

Access: Open access

Date: 2007-01-01

Creator: Michael W. Otto, Teresa M. Leyro, Kelly Christian, Christen M. Deveney, Hannah, Reese, Mark H. Pollack, Scott P. Orr

Access: Open access

Studies using fear-conditioning paradigms have found that anxiety patients are more conditionable than individuals without these disorders, but these effects have been demonstrated inconsistently. It is unclear whether these findings have etiological significance or whether enhanced conditionability is linked only to certain anxiety characteristics. To further examine these issues, the authors assessed the predictive significance of relevant subsyndromal characteristics in 72 healthy adults, including measures of worry, avoidance, anxious mood, depressed mood, and fears of anxiety symptoms (anxiety sensitivity), as well as the dimensions of Neuroticism and Extraversion. Of these variables, the authors found that the combination of higher levels of subsyndromal worry and lower levels of behavioral avoidance predicted heightened conditionability, raising questions about the etiological significance of these variables in the acquisition or maintenance of anxiety disorders. In contrast, the authors found that anxiety sensitivity was more linked to individual differences in orienting response than differences in conditioning per se. © 2007 Sage Publications.

Date: 2008-10-13

Creator: Thomas Pietraho

Access: Open access

We examine the partition of a finite Coxeter group of type B into cells determined by a weight function L. The main objective of these notes is to reconcile Lusztig's description of constructible representations in this setting with conjectured combinatorial descriptions of cells.

Date: 2008-03-28

Creator: Francisco Barceló, José A. Periáñez, Erika Nyhus

Access: Open access

This study aimed to clarify the neural substrates of behavioral switch and restart costs in intermittently instructed task-switching paradigms. Event-related potentials (ERPs) were recorded while participants were intermittently cued to switch or repeat their categorization rule (Switch task), or else they performed two perceptually identical control conditions (NoGo and Oddball). The three tasks involved different task-sets with distinct stimulus-response associations in each, but identical visual stimulation, consisting of frequent colored shapes (p = 0.9) and randomly interspersed infrequent black shapes (p = 0.1; '+' and 'x' symbols). Behavioral restart costs were observed in the first target responses following all black shapes in the Switch and NoGo tasks - but not in the Oddball task - and corresponded with enhanced fronto-centrally distributed early cue-locked P3 activity (peak latency 325-375 ms post-cue onset at the vertex). In turn, behavioral switch costs were associated with larger late cue-locked P3 amplitudes in the Switch task only (peak latency 400-450 ms post-cue onset at mid-parietal sites). Together with our information theoretical estimations, ERP results suggested that restart and switch costs indexed two neural mechanisms related to the preparatory resolution of uncertainty: (1) the intermittent re-activation of task-set information, and (2) the updating of stimulus-response mappings within an active task set, as indexed by early and late cue-locked P3 activations, respectively. In contrast, target-locked P3 activations reflected a functionally distinct mechanism related to the implementation of task-set information. We conclude that task-switching costs consist of both switch-specific and switch-unspecific processes during the preparation and execution stages of task performance. © 2008 Barceló, Periáñez and Nyhus.

Date: 1921-01-01

Access: Open access