Showing 3671 - 3680 of 5708 Items

Date: 2023-01-01
Creator: Catherine Crouch
Access: Access restricted to the Bowdoin Community

Date: 2021-01-01
Creator: Lily Andra McVetty
Access: Access restricted to the Bowdoin Community
Date: 2003-01-01
Creator: M. Saijo, T.W. Baumgarte, S.L. Shapiro
Access: Open access

Date: 2023-01-01
Creator: Sydney M Bonauto
Access: Access restricted to the Bowdoin Community
Date: 2016-05-01
Creator: John L Anderson
Access: Open access
- This study specifies the types of consumers that participate in the U.S. organic market and investigates their revealed preferences. I propose three theoretical consumer types – indifferent consumers, informed organic food lovers, and uninformed organic food lovers – and conduct cross-sectional and time-trend analyses utilizing organic fruit purchase data compiled by The Neilsen Company. The cross-sectional analysis is estimated with a two-stage Heckman selection model, while the time-trend analysis uses simple descriptive statistics and a differenced OLS regression technique. Households are most likely to participate in the organic fruit market if they have a well-educated white or Asian head, are located in a metropolitan area on the West coast, have higher income, have young children, are married, and are making decisions in the spring, summer, or fall. However, households are estimated to purchase more organic fruit, conditional on participating, if they live in a rural area in regions other than the West coast. Having a higher income, being married, having a child less than six years old, being college-educated, and living in a metropolitan area on the West coast are all associated with more dedication to the organic fruit market over time. Households who increased their organic expenditures from 2011 to 2012 likely lived in metropolitan areas on the West coast. Average per-household contribution to the nationwide increase in organic fruit expenditures from 2011 to 2012 on the extensive and intensive margins is estimated to have been about $7 and $14, respectively. I posit relationships between empirical results and the theoretical consumer types.

Date: 2024-01-01
Creator: Lillyana Browder
Access: Access restricted to the Bowdoin Community
Date: 2009-04-15
Creator: Patsy S. Dickinson, Teerawat Wiwatpanit, Emily R. Gabranski, Rachel J. Ackerman, Jake S., Stevens, Christopher R. Cashman, Elizabeth A. Stemmler, Andrew E. Christie
Access: Open access
- The allatostatins comprise three structurally distinct peptide families that regulate juvenile hormone production by the insect corpora allata. A-type family members contain the C-terminal motif -YXFGLamide and have been found in species from numerous arthropod taxa. Members of the B-type family exhibit a -WX6Wamide C-terminus and, like the A-type peptides, appear to be broadly conserved within the Arthropoda. By contrast, members of the C-type family, typified by the unblocked C-terminus -PISCF, a pyroglutamine blocked N-terminus, and a disulfide bridge between two internal Cys residues, have only been found in holometabolous insects, i.e. lepidopterans and dipterans. Here, using transcriptomics, we have identified SYWKQCAFNAVSCFamide (disulfide bridging predicted between the two Cys residues), a known honeybee and water flea C-typelike peptide, from the American lobster Homarus americanus (infraorder Astacidea). Using matrix assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FTMS), a mass corresponding to that of SYWKQCAFNAVSCFamide was detected in the H. americanus brain, supporting the existence of this peptide and its theorized structure. Furthermore, SYWKQCAFNAVSCFamide was detected by MALDI-FTMS in neural tissues from five additional astacideans as well as 19 members of four other decapod infraorders (i.e. Achelata, Anomura, Brachyura and Thalassinidea), suggesting that it is a broadly conserved decapod peptide. In H. americanus, SYWKQCAFNAVSCFamide is capable of modulating the output of both the pyloric circuit of the stomatogastric nervous system and the heart. This is the first demonstration of bioactivity for this peptide in any species.
Date: 2024-01-01
Creator: Liat G. Tesfazgi
Access: Open access
- From the perspective of Ethiopian royalists, Pan-Africanists, Marxist internationalists, supports of union, and the broader international community, Eritrean nationalism revealed distressing fissures in many different arguments for preserving Ethiopian territorial unity– arguments not necessarily or explicitly problematic, but nevertheless in opposition to Eritrean demands for the right to national self-determination. For the Ethiopian Student Movement (ESM) specifically, Eritrean sovereignty demanded a reconfiguration of Pan-African unity that conflicted with Ethiopian exceptionalist historiography. Through an analysis of student politics at Haile Selassie University, from 1960-1974, this thesis seeks to complicate existing historiography on the ESM by examining the periodically divergent experiences of Eritrean student activists.
Date: 2024-01-01
Creator: Josephine P. Tidmore
Access: Open access
- Central pattern generator (CPG) networks produce the rhythmic motor patterns that underlie critical behaviors such as breathing, walking, and heartbeat. The fidelity of these neural circuits in response to fluctuations in environmental conditions is essential for organismal survival. The specific ion channel profile of a neuron dictates its electrophysiological phenotype and is under homeostatic control, as channel proteins are constantly turning over in the membrane in response to internal and external stimuli. Neuronal function depends on ion channels and biophysical processes that are sensitive to external variables such as temperature, pH, and salinity. Nonetheless, the nervous system of the American lobster (Homarus americanus) is robust to global perturbations in these variables. The cardiac ganglion (CG), the CPG that controls the rhythmic activation of the heart in the lobster, has been shown to maintain function across a relatively wide, ecologically-relevant range of saline concentrations in the short-term. This study investigates whether individual neurons of the CG sense and compensate for long-term changes in extracellular ion concentration by controlling their ion channel mRNA abundances. To do this, I bathed the isolated CG in either 0.75x, 1.5x, or 1x (physiological) saline concentrations for 24 h. I then dissected out individual CG motor neurons, the pacemaker neurons, and sections of axonal projections and used single-cell RT-qPCR to measure relative mRNA abundances of several species of ion channels in these cells. I found that the CG maintained stable output with 24 h exposure to altered saline concentrations (0.75x and 1.5x), and that this stability may indeed be enabled by changes in mRNA abundances and correlated channel relationships.

Date: 2018-05-01
Creator: Shea Cristina Necheles
Access: Access restricted to the Bowdoin Community