Faculty Scholarship
Showing 221 - 230 of 733 Items
How Did Exchange Rates Affect Employment in US Cities?
Date: 2013-05-07
Creator: Yao Tang, Haifang Huang
Access: Open access
- We estimate the effects of real exchange rate movements on employment in US cities between 2003 and 2010. We explore the differences in the composition of local industries to construct city-specific changes in exchange rates and estimate their effects on local employment in manufacturing industries and in nonmanufacturing industries. Controlling for year and city fixed effects, we find that a depreciation of the US dollar increased local employment in the manufacturing industries, our proxy for the tradable sector. The depreciation also increased employment in the nonmanufacturing industries, the nontradable sector. Furthermore, the effects on nonmanufacturing employment were stronger in cities that had a higher fraction of manufacturing employment, indicating the exchange rate movements’ indirect effects through the manufacturing industries. We also consider an alternative definition of the tradable sector that is broadened to include five service industries. The findings are similar.
The organization (re)invented by its blogs
Date: 2013-04-12
Creator: Alex Primo
Access: Open access
- This article discusses how interactions in organizational blogs participate in the emergence of the organization itself. Based on the principles of The Montreal School of organizational communication, the paper reflects on how the recursive relationship between texts and conversations in blogs, according to their affordances, mobilizes the organization and contributes to its continuing creation. In order to conduct this argument, the concept of social media, uses of organizational blogs and the main contributions of The Montreal School are analyzed. Finally, this article demonstrates how blogs contribute to the definition of the organization. Beyond their promotional potential, the blog’ role as co-creator of the organization is highlighted.
Partner choice in spontaneous mitotic recombination in wild type and homologous recombination mutants of Candida albicans
Date: 2019-11-01
Creator: Alberto Bellido, Toni Ciudad, Belén Hermosa, Encarnación Andaluz, Anja, Forche, Germán Larriba
Access: Open access
- Candida albicans, the most common fungal pathogen, is a diploid with a genome that is rich in repeats and has high levels of heterozygosity. To study the role of different recombination pathways on direct-repeat recombination, we replaced either allele of the RAD52 gene (Chr6) with the URA-blaster cassette (hisG-URA3-hisG), measured rates of URA3 loss as resistance to 5-fluoroorotic acid (5FOAR) and used CHEF Southern hybridization and SNP-RFLP analysis to identify recombination mechanisms and their frequency in wildtype and recombination mutants. FOAR rates varied little across different strain backgrounds. In contrast, the type and frequency of mechanisms underlying direct repeat recombination varied greatly. For example, wildtype, rad59 and lig4 strains all displayed a bias for URA3 loss via pop-out/deletion vs. inter-homolog recombination and this bias was reduced in rad51 mutants. In addition, in rad51-derived 5FOAR strains direct repeat recombination was associated with ectopic translocation (5%), chromosome loss/truncation (14%) and inter-homolog recombination (6%). In the absence of RAD52, URA3 loss was mostly due to chromosome loss and truncation (80–90%), and the bias of retained allele frequency points to the presence of a recessive lethal allele on Chr6B. However, a few single-strand annealing (SSA)-like events were identified and these were independent of either Rad59 or Lig4. Finally, the specific sizes of Chr6 truncations suggest that the inserted URA-blaster could represent a fragile site.
Development of Rare Bacterial Monosaccharide Analogs for Metabolic Glycan Labeling in Pathogenic Bacteria
Date: 2016-12-16
Creator: Emily L. Clark, Madhu Emmadi, Katharine L. Krupp, Ananda R. Podilapu, Jennifer D., Helble, Suvarn S. Kulkarni, Danielle H. Dube
Access: Open access
- Bacterial glycans contain rare, exclusively bacterial monosaccharides that are frequently linked to pathogenesis and essentially absent from human cells. Therefore, bacterial glycans are intriguing molecular targets. However, systematic discovery of bacterial glycoproteins is hampered by the presence of rare deoxy amino sugars, which are refractory to traditional glycan-binding reagents. Thus, the development of chemical tools that label bacterial glycans is a crucial step toward discovering and targeting these biomolecules. Here, we explore the extent to which metabolic glycan labeling facilitates the studying and targeting of glycoproteins in a range of pathogenic and symbiotic bacterial strains. We began with an azide-containing analog of the naturally abundant monosaccharide N-acetylglucosamine and discovered that it is not broadly incorporated into bacterial glycans, thus revealing a need for additional azidosugar substrates to broaden the utility of metabolic glycan labeling in bacteria. Therefore, we designed and synthesized analogs of the rare deoxy amino d-sugars N-acetylfucosamine, bacillosamine, and 2,4-diacetamido-2,4,6-trideoxygalactose and established that these analogs are differentially incorporated into glycan-containing structures in a range of pathogenic and symbiotic bacterial species. Further application of these analogs will refine our knowledge of the glycan repertoire in diverse bacteria and may find utility in treating a variety of infectious diseases with selectivity.
Nonlinear vibrational-state excitation and piezoelectric energy conversion in harmonically driven granular chains
Date: 2016-05-05
Creator: C. Chong, E. Kim, E. G. Charalampidis, H. Kim, F., Li, P. G. Kevrekidis
Access: Open access
- This article explores the excitation of different vibrational states in a spatially extended dynamical system through theory and experiment. As a prototypical example, we consider a one-dimensional packing of spherical particles (a so-called granular chain) that is subject to harmonic boundary excitation. The combination of the multimodal nature of the system and the strong coupling between the particles due to the nonlinear Hertzian contact force leads to broad regions in frequency where different vibrational states are possible. In certain parametric regions, we demonstrate that the nonlinear Schrödinger equation predicts the corresponding modes fairly well. The electromechanical model we apply predicts accurately the conversion from the obtained mechanical energy to the electrical energy observed in experiments.
Unidirectional Transition Waves in Bistable Lattices
Date: 2016-06-13
Creator: Neel Nadkarni, Andres F. Arrieta, Christopher Chong, Dennis M. Kochmann, Chiara, Daraio
Access: Open access
- We present a model system for strongly nonlinear transition waves generated in a periodic lattice of bistable members connected by magnetic links. The asymmetry of the on-site energy wells created by the bistable members produces a mechanical diode that supports only unidirectional transition wave propagation with constant wave velocity. We theoretically justify the cause of the unidirectionality of the transition wave and confirm these predictions by experiments and simulations. We further identify how the wave velocity and profile are uniquely linked to the double-well energy landscape, which serves as a blueprint for transition wave control.
A tale of two exponentiations in N=8 supergravity
Date: 2019-11-10
Creator: Paolo Di Vecchia, Andrés Luna, Stephen G. Naculich, Rodolfo Russo, Gabriele, Veneziano, Chris D. White
Access: Open access
- The structure of scattering amplitudes in supergravity theories continues to be of interest. Recently, the amplitude for 2→2 scattering in N=8 supergravity was presented at three-loop order for the first time. The result can be written in terms of an exponentiated one-loop contribution, modulo a remainder function which is free of infrared singularities, but contains leading terms in the high energy Regge limit. We explain the origin of these terms from a well-known, unitarity-restoring exponentiation of the high-energy gravitational S-matrix in impact-parameter space. Furthermore, we predict the existence of similar terms in the remainder function at all higher loop orders. Our results provide a non-trivial cross-check of the recent three-loop calculation, and a necessary consistency constraint for any future calculation at higher loops.
Climate change and dissolved organic carbon export to the Gulf of Maine
Date: 2016-10-01
Creator: Thomas G. Huntington, William M. Balch, George R. Aiken, Justin Sheffield, Lifeng, Luo, Collin S. Roesler, Philip Camill
Access: Open access
- Ongoing climate change is affecting the concentration, export (flux), and timing of dissolved organic carbon (DOC) exported to the Gulf of Maine (GoM) through changes in hydrologic regime. DOC export was calculated for water years 1950 through 2013 for 20 rivers and for water years 1930 through 2013 for 14 rivers draining to the GoM. DOC export was also estimated for the 21st century based on climate and hydrologic modeling in a previously published study. DOC export was calculated by using the regression model LOADEST to fit seasonally adjusted concentration discharge (C-Q) relations. Our results are an analysis of the sensitivity of DOC export to changes in hydrologic conditions over time since land cover and vegetation were held constant over time. Despite large interannual variability, all rivers had increasing DOC export during winter and these trends were significant (p < 0.05) in 10 out of 20 rivers for 1950 to 2013 and in 13 out of 14 rivers for 1930 to 2013. All rivers also had increasing annual export of DOC although fewer trends were statistically significant than for winter export. Projections for DOC export during the 21st century were variable depending on the climate model and greenhouse gas emission scenario that affected future river discharge through effects on precipitation and evapotranspiration. The most consistent result was a significant increase in DOC export in winter in all model-by-emission scenarios. DOC export was projected to decrease during the summer in all model-by-emission scenarios, with statistically significant decreases in half of the scenarios.
A mutation in Tac1p, a transcription factor regulating CDR1 and CDR2, is coupled with loss of heterozygosity at chromosome 5 to mediate antifungal resistance in Candida albicans
Date: 2006-04-01
Creator: Alix Coste, Vincent Turner, Françoise Ischer, Joachim Morschhäuser, Anja, Forche, Anna Selmecki, Judith Berman, Jacques Bille, Dominique Sanglard
Access: Open access
- TAC1, a Candida albicans transcription factor situated near the mating-type locus on chromosome 5, is necessary for the upregulation of the ABC-transporter genes CDR1 and CDR2, which mediate azole resistance. We showed previously the existence of both wild-type and hyperactive TAC1 alleles. Wild-type alleles mediate upregulation of CDR1 and CDR2 upon exposure to inducers such as fluphenazine, while hyperactive alleles result in constitutive high expression of CDR1 and CDR2. Here we recovered TAC1 alleles from two pairs of matched azole-susceptible (DSY294; FH1: heterozygous at mating-type locus) and azole-resistant isolates (DSY296; FH3: homozygous at mating-type locus). Two different TAC1 wild-type alleles were recovered from DSY294 (TAC1-3 and TAC1-4) while a single hyperactive allele (TAC1-5) was isolated from DSY296. A single amino acid (aa) difference between TAC1-4 and TAC1-5 (Asn977 to Asp or N977D) was observed in a region corresponding to the predicted activation domain of Tac1p. Two TAC1 alleles were recovered from FH1 (TAC1-6 and TAC1-7) and a single hyperactive allele (TAC1-7) was recovered from FH3. The N977D change was seen in TAC1-7 in addition to several other aa differences. The importance of N977D in conferring hyperactivity to TAC1 was confirmed by site-directed mutagenesis. Both hyperactive alleles TAC1-5 and TAC1-7 were codominant with wild-type alleles and conferred hyperactive phenotypes only when homozygous. The mechanisms by which hyperactive alleles become homozygous was addressed by comparative genome hybridization and single nucleotide polymorphism arrays and indicated that loss of TAC1 heterozygosity can occur by recombination between portions of chromosome 5 or by chromosome 5 duplication. Copyright © 2006 by the Genetics Society of America.
Investigating the Role of Interpretation Bias in Mindfulness-Based Treatment of Adults With Generalized Anxiety Disorder
Date: 2020-02-11
Creator: Elizabeth A. Hoge, Hannah E. Reese, Isabelle A. Oliva, Caroline D. Gabriel, Brittany M., Guidos, Eric Bui, Naomi M. Simon, Mary Ann Dutton
Access: Open access
- Although mindfulness-based interventions (MBIs) have garnered empirical support for a wide range of psychological conditions, the psychological processes that mediate the relationship between MBIs and subsequent symptomatic improvement are less well-understood. In the present study we sought to examine, for the first time, the relationship between mindfulness, negative interpretation bias as measured by the homophone task, and anxiety among adults with Generalized Anxiety Disorder (GAD). Forty-two individuals with GAD completed measures of mindfulness, interpretation bias, and anxiety before and after treatment with Mindfulness-based Stress Reduction (MBSR). Contrary to prior research, we did not find evidence of an indirect relationship between baseline levels of mindfulness and anxiety via negative interpretation bias. MBSR did result in significant reductions in negative interpretation bias from baseline to post-treatment; however, we did not find evidence of an indirect relationship between changes in mindfulness and changes in anxiety via changes in interpretation bias. Taken together, these results provide minimal support for the hypothesized relationship between mindfulness, negative interpretation bias, and anxiety among adults with GAD. Limitations and specific suggestions for further inquiry are discussed.