303 research outputs found
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Biofuels & atmospheric chemistry: what can a global model tell us about our future decisions?
Biomass energy is the oldest form of energy harnessed by humans. Currently,
processed biofuels, which are derived from biomass, are being pursued as a possi-
ble route to decarbonize the transport sector—a particularly difficult task for both
technological and sociological reasons. In this thesis I explore the impacts that
large scale biofuel use could have on atmospheric chemistry.
I review the current state of biofuels politically and technologically, focusing
on ethanol and biodiesel. I discuss the salient features of tropospheric chemistry
and in particular the oxidation of isoprene, an important biogenic volatile organic
compound. I examine the impact that including isoprene oxidation has in a new
chemistry-climate computer model, UKCA; the response of ozone turns out to
depend on local chemical conditions. To evaluate the global model, I use data
from the OP3 field campaign in Malaysia and compare it with output from the
model chemical mechanism. The mechanism is able to reproduce NOx and ozone
measurements well, though is more sensitive to representations of physical rather
than chemical processes. I also perform a simple sensitivity study which examines
crop changes in the region of Southeast Asia.
In the final two chapters, I turn to two distinct phases of the biofuel life cycle. I
characterize a potential future atmosphere through an ozone attribution study, then
examine the impact of future cropland expansion (phase I of a biofuel life cycle)
on tropospheric chemistry. I find that land use change has a large impact on ozone,
and that it is more acute than another perturbation (CO2 suppression) to isoprene
emissions. I then move to phase III of the life cycle—combustion—and look at the
sensitivity of the model chemistry to surface transport emissions from biofuels as
a replacement for conventional fuels. I find that biodiesel reduces surface ozone,
while ethanol increases it, and that the response has both a linear and nonlinear
component
Exploring Public Health Citation Networks: A Pilot Project to Determine the Publishing Patterns in Racial and Ethnic Health Disparity Research
Objective: The study identifies the most heavily cited journal titles, publication types, and subject disciplines in racial and ethnic health disparities research. The overall goal is to assist librarians with collection assessment for diversity and disparity-related research, and to provide a resource to assist faculty with identifying potential sources for publication. Methods: Using a modified version of the literature mapping protocol developed by the Nursing and Allied Health Resources Section, this study analyzed the references from research articles published in 2016 in racial and ethnic health disparities journals. Four journals were selected based on coverage of racial and ethnic disparities, and input from health disparities researchers. For eachreference, publication type, publication date, and journal title, if it is an article, was recorded. To identify the core journals, cited journals were divided into three zones using Bradford’s Law of Scattering. A single subject discipline was assigned to each core journal based on Library of Congress classification, as determined by Ulrich’s Web. Results: 332 articles from four journals yielded 13,023 references. Journal articles were the most heavily cited publication type (n=10,596, 81%), followed bygovernment reports (n=1005, 8%). Age of citations ranged 163 years, with 41% (n=5339) of citations occurring within the previous 8 years. The peak age of citations for articles was 6 years. Forty-two core journals accounted for 33.8% of all citations. Themost common subject disciplines of these core journals were medicine (n=15), and public health and population health (n=15), followed by ethnic interests (n=4). Conclusion: Similar to other public health-related fields, racial and ethnic health disparity research draws from a very diverse pool of subject disciplines from medicine to public health to the social sciences, and relies on older articles and reports published within the last twenty years. However, racial and ethnic disparity research does not rely as heavily on government reports or miscellaneous items as other public health and social services disciplines
Does Our Web Site Stress You Out? Information Foraging and the Psychophysiology of Online Navigation
Beyond Systematic Reviews: Finding Our Place in the Academic Research Process
Objective: Are library-based research services addressing the practical needs of faculty? Could librarians be neglecting a range of opportunities in the research process by only focusing on systematic reviews? Two medical librarians at a large, Midwestern institution sought to integrate themselves into the research process for their respective schools by using a holistic approach towards embedded librarianship in an academic environment.
Methods: Across the research lifecycle, we have created a culture of acceptance for librarians to be included at every step. In the beginning, many faculty members were not aware of how we could help them beyond systematic reviews. As liaisons, we first began by marketing our services to junior faculty by finding relevant grant funding, conducting literature reviews that supported their research projects, and writing the methods sections regarding searches for any articles that resulted from our work. Following the publication of an article, we also helped with any public access compliance needs, worked to archive their manuscripts, and collected metrics for promotion and tenure purposes. We have actively worked towards being included in all aspects of faculty research, and have three years of combined data to support our program of embedded research support
A role for the extended amygdala in the fear-enhancing effects of acute selective serotonin reuptake inhibitor treatment
Selective serotonin reuptake inhibitors (SSRIs) are reported to exacerbate symptoms of anxiety when treatment is initiated. These clinical findings have been extended to animal models wherein SSRIs also potentiate anxiety and fear learning, which depend on the amygdala. Yet, little is known about the role of specific amygdalar circuits in these acute effects of SSRIs. Here, we first confirmed that a single injection of fluoxetine 1 h before auditory fear conditioning potentiated fear memory in rats. To probe the neural substrates underlying this enhancement, we analyzed the expression patterns of the immediate early gene, Arc (activity-regulated cytoskeleton-associated protein). Consistent with previous reports, fear conditioning induced Arc protein expression in the lateral and basal amygdala. However, this was not enhanced further by pre-treatment with fluoxetine. Instead, fluoxetine significantly enhanced expression of Arc in the central amygdala (CeA) and the bed nucleus of the stria terminalis (BNST). Next, we tested whether direct targeted infusions of fluoxetine into the CeA, or BNST, leads to the same fear-potentiating effect. Strikingly, direct infusion of fluoxetine into the BNST, but not the CeA, was sufficient to enhance fear memory. Moreover, this behavioral effect was also accompanied by robust Arc expression in the CeA, similar to the systemic injection. Our results identify a novel role for the BNST in the acute fear-enhancing effects of SSRIs. These findings highlight the need to look beyond the traditional focus on input nuclei of the amygdala and add to accumulating evidence implicating these microcircuits in gating fear and anxiety
Molybdenum Complexes of Chiral C2-symmetric Picchxn-type Ligands: Synthesis, Characterization, and Structural Studies
A series of molybdenum complexes based on chiral C2-symmetric picchxn-type ligands (N4 ligands, defined as trans-N,N′-bis(heterocycl-2-ylmethyl)-1,2-diaminocyclohexanes) has been synthesized and characterized. Reported and novel picchxn-type ligands form (κ3-N4)Mo(CO)3, [(κ4-N4)Mo(NO)(CO)]PF6, and [(κ4-N4)Mo(NO)X]PF6 (X = Br, I) compounds. Multiple tridentate (κ3) and tetradentate (κ4) ligand configurations were observed, and the favored κ4 configuration was found to vary with N4 heterocycle identity. Heterocycle variation allowed for directed modification of the molybdenum electronic characteristics, but none of the studied {(κ4-N4)Mo(NO)}+ fragments was found to be a suitable π-base for dearomatization chemistry. The crystal structures of eight molybdenum complexes with picchxn-type ligands were determined
Activity of ceftazidime/avibactam against problem Enterobacteriaceae and Pseudomonas aeruginosa in the UK, 2015-2016
Background: Ceftazidime/avibactam combines an established oxyimino-cephalosporin with the first diazabicyclooctane β-lactamase inhibitor to enter clinical use. We reviewed its activity against Gram-negative isolates, predominantly from the UK, referred for resistance investigation in the first year of routine testing, beginning in July 2015. Methods: Isolates were as received from referring laboratories; there is a bias to submit those with suspected carbapenem resistance. Identification was by MALDI-TOF mass spectroscopy, and susceptibility testing by BSAC agar dilution. Carbapenemase genes were sought by PCR; other resistance mechanisms were inferred using genetic data and interpretive reading. Results: Susceptibility rates to ceftazidime/avibactam exceeded 95% for: (i) Enterobacteriaceae with KPC, GES or other Class A carbapenemases; (ii) Enterobacteriaceae with OXA-48-like enzymes; and (iii) for ESBL or AmpC producers, even when these had impermeability-mediated ertapenem resistance. Almost all isolates with metallo-carbapenemases were resistant. Potentiation of ceftazidime by avibactam was seen for 87% of ceftazidime-resistant Enterobacteriaceae with ‘unassigned’ ceftazidime resistance mechanisms, including two widely referred groups of Klebsiella pneumoniae where no synergy was seen between cephalosporins and established β-lactamase inhibitors. Potentiation here may be a diazabicyclooctane/cephalosporin enhancer effect. Activity was seen against Pseudomonas aeruginosa with derepressed AmpC, but not for those with efflux-mediated resistance. Conclusions: Of the available β-lactams or inhibitor combinations, ceftazidime/avibactam has the widest activity spectrum against problem Enterobacteriaceae, covering all major types except metallo-carbapenemase producers; against P. aeruginosa it has a slightly narrower spectrum than ceftolozane/tazobactam, which also covers efflux-type resistance
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