1,531 research outputs found
Misremembering Reagan: A Decade of Cultural Dissent
Presidential legacies are constructed, and for the Republican Party perhaps no figure has benefitted from mythology, hagiography, and misremembrances than Ronald Wilson Reagan. Popularly, America’s 40th President is frequently remembered as residing over a massive economic upswing, restoring faith in the American military, and ushering in the end of the Cold War—combining to construct an image of a beloved, even visionary leader. Looking back at popular culture from the 1980s, however, paints a very different picture. From Reagan’s relationship with the press, his shortcomings acknowledging struggles in the African American community, to his near-legacy shattering handling of the Iran Contra crisis, 1980s popular culture helps to remind us that Reagan was not so nearly beloved as today’s pundits would have us believe
Optical properties of the iron-pnictide analog BaMn2As2
We have investigated the infrared and Raman optical properties of BaMn2As2 in
the ab-plane and along the c-axis. The most prominent features in the infrared
spectra are the Eu and A2u phonon modes which show clear TO-LO splitting from
the energy loss function analysis. All the phonon features we observed in
infrared and Raman spectra are consistent with the calculated values. Compared
to the iron-pnictide analog AFe2As2, this compound is much more two-dimensional
in its electronic properties. For E || c-axis, the overall infrared
reflectivity is insulating like. Within the ab-plane the material exhibits a
semiconducting behavior. An energy gap 2{\Delta}=48 meV can be clearly
identified below room temperature.Comment: 5 pages, 7 figure
Spectroscopy of PTCDA attached to rare gas samples: clusters vs. bulk matrices. I. Absorption spectroscopy
The interaction between PTCDA (3,4,9,10-perylene-tetracarboxylic-dianhydride)
and rare gas or para-hydrogen samples is studied by means of laser-induced
fluorescence excitation spectroscopy. The comparison between spectra of PTCDA
embedded in a neon matrix and spectra attached to large neon clusters shows
that these large organic molecules reside on the surface of the clusters when
doped by the pick-up technique. PTCDA molecules can adopt different
conformations when attached to argon, neon and para-hydrogen clusters which
implies that the surface of such clusters has a well-defined structure and has
not liquid or fluxional properties. Moreover, a precise analysis of the doping
process of these clusters reveals that the mobility of large molecules on the
cluster surface is quenched, preventing agglomeration and complex formation
Robust and Scalable Bayesian Online Changepoint Detection
This paper proposes an online, provably robust, and scalable Bayesian approach for changepoint detection. The resulting algorithm has key advantages over previous work: it provides provable robustness by leveraging the generalised Bayesian perspective, and also addresses the scalability issues of previous attempts. Specifically, the proposed generalised Bayesian formalism leads to conjugate posteriors whose parameters are available in closed form by leveraging diffusion score matching. The resulting algorithm is exact, can be updated through simple algebra, and is more than 10 times faster than its closest competitor
Liver pathology in rural south-west Cameroon
In a prospective study, 102 hospital patients with liver disease were evaluated in West Cameroon, Africa. Blood donors, pregnant women and patients without liver disease served as controls. A total of 757 individuals were tested for markers of hepatitis A, B, C and D and for immunological markers (autoantibodies, procollagen III, α-foetoprotein, CA50 antigen, α-1-antitrypsin and antibodies to human immunodeficiency virus types 1 and 2). One-third of the liver disease patients had focal lesions on ultrasound examination. Histologically, 20 cases of cirrhosis, 14 cases of chronic hepatitis, 15 hepatocellular carcinomas and 17 cases of acute hepatitis were detected. All hepatic patients and virtually all controls had had a previous hepatitis A virus infection. Over 85% of adult patients and controls had at least one marker of hepatitis B virus infection. Over 30% of patients with liver disease had markers of possible hepatitis B virus replication. Antihepatitis C virus antibody was present in 18% of hepatic patients and in 6% of controls. Hepatitis C virus infection seems to play an important role in the development of chronic liver pathology; 40% of cirrhotic patients had a combined hepatitis B and C virus infection, Serum autoantibodies were frequently found and were not correlated with the presence of autoimmune liver diseas
Tracing the catchment-scale hydrology of polygonal tundra and implications for lateral fluxes of carbon and nitrogen, Lena River Delta, Siberia
Zero delay synchronization of chaos in coupled map lattices
We show that two coupled map lattices that are mutually coupled to one
another with a delay can display zero delay synchronization if they are driven
by a third coupled map lattice. We analytically estimate the parametric regimes
that lead to synchronization and show that the presence of mutual delays
enhances synchronization to some extent. The zero delay or isochronal
synchronization is reasonably robust against mismatches in the internal
parameters of the coupled map lattices and we analytically estimate the
synchronization error bounds.Comment: 9 pages, 9 figures ; To appear in Phys. Rev.
Greenhouse gas production in degrading ice-rich permafrost deposits in northeastern Siberia
Permafrost deposits have been a sink for atmospheric carbon for millennia. Thaw-erosional processes, however, can lead to rapid degradation of ice-rich permafrost and the release of substantial amounts of organic carbon (OC). The amount of the OC stored in these deposits and their potential to be microbially decomposed to the greenhouse gases carbon dioxide (CO2) and methane (CH4) depends on climatic and environmental conditions during deposition and the decomposition history before incorporation into the permafrost. Here, we examine potential greenhouse gas production in degrading ice-rich permafrost deposits from three locations in the northeast Siberian Laptev Sea region. The deposits span a period of about 55 kyr from the last glacial period and Holocene interglacial. Samples from all three locations were incubated under aerobic and anaerobic conditions for 134 days at 4 °C. Greenhouse gas production was generally higher in deposits from glacial periods, where 0.2–6.1% of the initially available OC was decomposed to CO2. In contrast, only 0.1–4.0% of initial OC were decomposed in permafrost deposits from the Holocene and the late glacial transition. Within the deposits from the Kargin interstadial period (Marine Isotope Stage 3), local depositional environments, especially soil moisture, also affected the preservation of OC. Sediments deposited under wet conditions contained more labile OC and thus produced more greenhouse gases than sediments deposited under drier conditions. To assess the greenhouse gas production potentials over longer periods, deposits from two locations were incubated for a total of 785 days. However, more than 50% of total CO2 production over 785 days occurred within the first 134 days under aerobic conditions while even 80% were produced over the same period under anaerobic conditions, which emphasizes the non-linearity of the OC decomposition processes. Methanogenesis was generally observed in active layer samples but only sporadically in permafrost samples and was several orders of magnitude smaller than CO2 production
Assessing and monitoring health impacts of infrastructure development projects in sub-Saharan Africa
In many sub-Saharan African countries, large infrastructure development projects in the natural resources, water management and agricultural sectors typically consider potential environmental and social impacts as part of the permitting process, while a specific focus on health impacts is often lacking. Health impact assessment (HIA) applies a combination of procedures, methods and tools that systematically judge the potential and sometimes unintended effects of a project on the health of a population and the distribution of those effects within the population. HIA seeks to predict health impacts and inform decision-makers on appropriate actions to manage those impacts with the ultimate goal to minimize negative health impacts and promote positive health impacts. As of 2016, there were few examples in the public domain on how health issues were addressed within an evidence-based HIA for large-scale projects in sub-Saharan Africa, despite monitoring and evaluation (M&E) being an integral part of the HIA process.
The main objective of this PhD thesis was to assess and monitor health impacts of infrastructure development and management projects in sub-Saharan Africa and to evaluate the effectiveness of HIA of large-scale infrastructure development projects to mitigate negative health impacts and promote health benefits. Several case studies from complex eco-epidemiological settings are presented focusing on implementation and outcomes of HIA of infrastructure development projects and on M&E of health outcomes and health-related indicators in communities potentially affected by these projects
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