Showing 2731 - 2740 of 5714 Items
“Bosques Si, Tala No”: The Uprising of Cherán K’eri
Date: 2020-01-01
Creator: Ray Tarango
Access: Open access
- In the spring of 2011, the indigenous community of Cherán K’eri in western Mexico rose up to protect their forests. Organized crime, and its allies, had taken over this town during the previous decade and had logged significant portions of its communal forests in the surrounding hills. This thesis examines the following questions: How do townspeople recall their experience under a narco state? What pushed this indigenous community to organize to protect the forest despite the threat of violence? What was it about this landscape in particular that brought people together? Previous research into this uprising has overlooked the gender dynamics of the community, and has failed to consider the townspeople’s connection to nature. Using interviews gathered over eighteen months in three separate visits, this thesis argues that despite patriarchal expectations that men “protect” the community and its resources it was women who led and organized the uprising. Chapter One analyzes how organized crime took control of the community, suggesting that memories and trauma of the “war on drugs” deeply affected the townspeople. Chapter Two centers on the uprising itself, exploring not only the gendered dynamics of that spring, but connecting the material and affective importance of the forest to the women who led the uprising. This thesis analyzes how organized crime took control of the community and argues that townspeople’s multilayered connection to nature played a central role in the town’s movement.
Observation of B0 decay to two charmless mesons
Date: 1993-01-01
Creator: M. Battle, J. Ernst, H. Kroha, Y. Kwon, S., Roberts, K. Sparks, E. H. Thorndike, C. H. Wang, J. Dominick, S. Sanghera, V. Shelkov, T. Skwarnicki, R. Stroynowski, I. Volobouev, P. Zadorozhny, M. Artuso, D. He, M. Goldberg, N. Horwitz, R. Kennett, G. C. Moneti, F. Muheim, Y. Mukhin, S. Playfer, Y. Rozen, S. Stone, M. Thulasidas, G. Vasseur, G. Zhu, J. Bartelt, S. E. Csorna
Access: Open access
- We report results from a search for the decays B0→π+π-, B0→K+π-, and B0→K+K-. We find 90% confidence level upper limits on the branching fractions, Bππ<2.9×10-5, BKπ<2.6×10-5, and BKK<0.7×10-5. While there is no statistically significant signal in the individual modes, the sum of Bππ and BKπ exceeds zero with a significance of more than 4 standard deviations, indicating that we have observed charmless hadronic B decays. © 1993 The American Physical Society.
Annual Reports of the President
- Report of the President, Bowdoin College (1891-2001) provides annual “state of the college” summaries issued by the Office of the President. Most issues also include annual reports of the librarian, the director of the Museum of Art, the curator of the Arctic Museum, the dean of the College, and for some years, reports by the registrar, the dean of the Medical School, the College physician, and the director of the Senior Center. Among the matters discussed are gifts and acquisitions, changes in programs and personnel, demographics and other statistical data.
The Role of the Golgi ELMO Proteins in Cell Adhesion in Arabidopsis thaliana
Date: 2021-01-01
Creator: Wesley James Hudson
Access: Open access
- Proper growth and development of plant cells is dependent upon successful cell adhesion between cells, and this is mostly mediated by pectin in the plant cell wall. Previously, the Kohorn Laboratory identified a non-enzymatic Golgi protein named ELMO1 as it is required for cell adhesion, likely acting as a scaffold for cell wall polymer synthesis. Plants with mutant ELMO1 demonstrate a weak defective cellular adhesion phenotype as well as reduced mannose content in the cell wall. ELMO1 has homologous proteins in at least 29 different vascular plants. These homologues have 2 possible deletions in their amino acid sequence, but protein modeling determined that these variations will not affect protein structure. There are 5 homologous ELMO1 proteins in Arabidopsis thaliana that have been aptly named ELMO2, ELMO3, ELMO4, ELMO5. elmo2-/-mutants revealed no mutant adhesion phenotypes, while elmo1-/-elmo2-/-double mutants revealed strong defects in adhesion. Confocal microscopy of propidium iodide-stained seedlings confirmed the lack of a phenotype for elmo2-/-mutants and showed disorganized gapping cells for the elmo1-/-elmo2-/-mutant. Additionally, while elmo2-/-did not have any change to root or hypocotyl length, elmo1-/-elmo2-/- mutants were significantly shorter in both regards. Taken together, these data support that ELMO2 and ELMO1 are partially redundant.
Molecular characterization of putative neuropeptide, amine, diffusible gas and small molecule transmitter biosynthetic enzymes in the eyestalk ganglia of the American lobster, Homarus americanus
Date: 2018-12-01
Creator: Andrew E. Christie, Meredith E. Stanhope, Helen I. Gandler, Tess J. Lameyer, Micah G., Pascual, Devlin N. Shea, Andy Yu, Patsy S. Dickinson, J. Joe Hull
Access: Open access
- The American lobster, Homarus americanus, is a model for investigating the neuromodulatory control of physiology and behavior. Prior studies have shown that multiple classes of chemicals serve as locally released/circulating neuromodulators/neurotransmitters in this species. Interestingly, while many neuroactive compounds are known from Homarus, little work has focused on identifying/characterizing the enzymes responsible for their biosynthesis, despite the fact that these enzymes are key components for regulating neuromodulation/neurotransmission. Here, an eyestalk ganglia-specific transcriptome was mined for transcripts encoding enzymes involved in neuropeptide, amine, diffusible gas and small molecule transmitter biosynthesis. Using known Drosophila melanogaster proteins as templates, transcripts encoding putative Homarus homologs of peptide precursor processing (signal peptide peptidase, prohormone processing protease and carboxypeptidase) and immature peptide modifying (glutaminyl cyclase, tyrosylprotein sulfotransferase, protein disulfide isomerase, peptidylglycine-α-hydroxylating monooxygenase and peptidyl-α-hydroxyglycine-α-amidating lyase) enzymes were identified in the eyestalk assembly. Similarly, transcripts encoding full complements of the enzymes responsible for dopamine [tryptophan-phenylalanine hydroxylase (TPH), tyrosine hydroxylase and DOPA decarboxylase (DDC)], octopamine (TPH, tyrosine decarboxylase and tyramine β-hydroxylase), serotonin (TPH or tryptophan hydroxylase and DDC) and histamine (histidine decarboxylase) biosynthesis were identified from the eyestalk ganglia, as were those responsible for the generation of the gases nitric oxide (nitric oxide synthase) and carbon monoxide (heme oxygenase), and the small molecule transmitters acetylcholine (choline acetyltransferase), glutamate (glutaminase) and GABA (glutamic acid decarboxylase). The presence and identity of the transcriptome-derived transcripts were confirmed using RT-PCR. The data presented here provide a foundation for future gene-based studies of neuromodulatory control at the level of neurotransmitter/modulator biosynthesis in Homarus.
Bowdoin College Catalogue (1943 Summer Trimester)
Date: 1943-01-01
Access: Open access
- Bowdoin College Bulletin no. 268
Lepton asymmetry measurements in B̄→D*l-ν̄l and implications for V-A and the form factors
Date: 1993-01-01
Creator: S. Sanghera, T. Skwarnicki, R. Stroynowski, M. Artuso, M., Goldberg, N. Horwitz, R. Kennett, G. C. Moneti, F. Muheim, S. Playfer, Y. Rozen, P. Rubin, S. Stone, M. Thulasidas, W. M. Yao, G. Zhu, A. V. Barnes, J. Bartelt, S. E. Csorna, Z. Egyed, V. Jain, P. Sheldon, D. S. Akerib, B. Barish, M. Chadha, D. F. Cowen, G. Eigen, J. S. Miller, J. Urheim, A. J. Weinstein, D. Acosta
Access: Open access
- We present a measurement of the lepton decay asymmetry Afb in the reaction B̄→D*l-ν̄l using data collected with the CLEO II detector at the Cornell Electron Storage Ring (CESR). The value of Afb confirms that the chirality of the weak interaction is predominantly left-handed in b→c transitions as expected in the standard model, if it is assumed that the lepton current is also left-handed. Using Afb and the previously determined branching ratio, q2 distribution, and D* polarization, we obtain the first measurement of the form-factor ratios that are used to describe this semileptonic decay. © 1993 The American Physical Society.
The Effects of Temperature on the Cardiac System of the American Lobster, Homarus americanus
Date: 2014-05-01
Creator: Elizabeth A Owens
Access: Open access
- The American lobster, Homarus americanus, inhabits a large oceanic range spanning from Labrador, Canada to North Carolina, USA. This geographic range varies in temperature by as much as 25ºC, and daily temperature fluctuations of up to 12ºC may occur at a single location depending on season, water depth, and tides. The cardiac system of the lobster is sensitive to these temperature changes, and has been shown to adjust its functioning over a large temperature range. A previous study showed that various functional parameters respond differently to temperature changes, but a stable cardiac output can be maintained over the range of 2-20ºC. The current study showed that the effects of temperature were exerted primarily through changes in the lobster heart central pattern generator, the cardiac ganglion. Similar patterns of change were seen in both semi-intact hearts and isolated cardiac ganglion preparations in response to increasing temperature. Specifically, with increasing temperature, the burst frequency showed a biphasic pattern in which frequency initially increased, then decreased rapidly at high temperatures. The burst duration, duty cycle, and number of spikes per burst generally decreased with increasing temperature, and spike frequency increased over the entire temperature range. Semi-intact hearts and isolated cardiac ganglia showed similar “crash” patterns, characterized by complete loss of function at high temperatures and complete recovery of function when temperature was returned to baseline. Feedback in the semi-intact heart provided some stabilization of bursting activity, but it did not provide the expected protection from high temperatures. The isolated CG had a significantly higher crash temperature than did the semi-intact system. This discrepancy in crash temperatures may be explained by considering factors at the level of the muscle and neuromuscular junction (NMJ), such as stretch and nitric oxide (NO) feedback and the balance of facilitation and depression at the NMJ. Stimulated preparations showed defacilitation of contraction amplitude at high temperatures despite the maintenance of constant burst parameters of stimulation. Therefore, several factors contributing to the relatively low crash temperature of the intact system may be a shift in the balance of facilitation and depression at the NMJ, a depression in ganglion function due to the release of NO by the muscle, or a combination of the two mechanisms.
Isospin mass splittings from precision measurements of D*-D mass differences
Date: 1992-01-01
Creator: D. Bortoletto, D. N. Brown, J. Dominick, R. L. Mcilwain, T., Miao, D. H. Miller, M. Modesitt, S. F. Schaffner, E. I. Shibata, I. P.J. Shipsey, M. Battle, J. Ernst, H. Kroha, S. Roberts, K. Sparks, E. H. Thorndike, C. H. Wang, S. Sanghera, T. Skwarnicki, R. Stroynowski, M. Artuso, M. Goldberg, N. Horwitz, R. Kennett, G. C. Moneti, F. Muheim, S. Playfer, Y. Rozen, P. Rubin, S. Stone, M. Thulasidas
Access: Open access
- Using the decay modes, D*+→D+π0 and D*0→D0π0, we have measured the D*+-D+ and D*0-D0 mass differences to be 140±0.08±0.06 and 142.12±0.05±0.05 MeV, respectively. Combining these measurements with the Particle Data Group average for the D*+-D0 mass difference, we obtain isospin mass splittings for D*+-Dusp*0 and D+-D0 of 3.32±0.08±0.05 and 4.80±0.10 ±0.06 MeV. We discuss the implications of these measurements for models of isospin mass differences and model-dependent estimates of fD. © 1992 The American Physical Society.
The pyloric neural circuit of the herbivorous crab Pugettia producta shows limited sensitivity to several neuromodulators that elicit robust effects in more opportunistically feeding decapods
Date: 2008-05-01
Creator: Patsy S. Dickinson, Elizabeth A. Stemmler, Andrew E. Christie
Access: Open access
- Modulation of neural circuits in the crustacean stomatogastric nervous system (STNS) allows flexibility in the movements of the foregut musculature. The extensive repertoire of such resulting motor patterns in dietary generalists is hypothesized to permit these animals to process varied foods. The foregut and STNS of Pugettia producta are similar to those of other decapods, but its diet is more uniform, consisting primarily of kelp. We investigated the distribution of highly conserved neuromodulators in the stomatogastric ganglion (STG) and neuroendocrine organs of Pugettia, and documented their effects on its pyloric rhythm. Using immunohistochemistry, we found that the distributions of Cancer borealis tachykinin-related peptide I (CabTRP I), crustacean cardioactive peptide (CCAP), proctolin, red pigment concentrating hormone (RPCH) and tyrosine hydroxylase (dopamine) were similar to those of other decapods. For all peptides except proctolin, the isoforms responsible for the immunoreactivity were confirmed by mass spectrometry to be the authentic peptides. Only two modulators had physiological effects on the pyloric circuit similar to those seen in other species. In non-rhythmic preparations, proctolin and the muscarinic acetylcholine agonist oxotremorine consistently initiated a full pyloric rhythm. Dopamine usually activated a pyloric rhythm, but this pattern was highly variable. In only about 25% of preparations, RPCH activated a pyloric rhythm similar to that seen in other species. CCAP and CabTRP I had no effect on the pyloric rhythm. Thus, whereas Pugettia possesses all the neuromodulators investigated, its pyloric rhythm, when compared with other decapods, appears less sensitive to many of them, perhaps because of its limited diet.