The impact of the 1996 Summer Olympic Games on employment and wages in Georgia

Using the standard differences-in-differences (DD) technique and a modified DD technique in the slopes, this paper determines that hosting the 1996 Summer Olympic Games boosted employment by 17% in the counties of Georgia affiliated with and close to Olympic activity, relative to employment increases in other counties in Georgia (the rate of growth increased by 0.002 percentage points per quarter). Estimation of a random-growth model confirms a positive impact of the Olympics on employment. In addition, the employment impact is shown not to be merely a "metropolitan statistical area (MSA) effect"; employment in the northern Olympic venue areas was found to increase 11% more post- versus pre-Olympics than it did in other, similar southern MSAs. The evidence of an Olympic impact on wages is weak

Freshman learning communities, college performance, and retention

This paper applies a standard treatment effects model to determine that participation in Freshman Learning Communities (FLCs) improves academic performance and retention. Not controlling for individual self-selection into FLC participation leads one to incorrectly conclude that the impact is the same across race and gender groups. Accurately assessing the impact of any educational program is essential in determining what resources institutions should devote to it.

Can continental bogs with stand the pressure due to climate change?

Not all peatlands are alike. Theoretical and process based models suggest that ombrogenic, oligotrophic peatlands can withstand the pressures due to climate change because of the feedbacks among ecosystem production, decomposition and water storage. Although there have been many inductive explanations inferring from paleo-records, there is a lack of deductive empirical tests of the models predictions of these systems’ stability and there are few records of the changes in the net ecosystem carbon balance (NECB) of peatlands that are long enough to examine the dynamics of the NECB in relation to climate variability. Continuous measurements of all the components of the NECB and the associated general climatic and environmental conditions have been made at the Mer Bleue (MB) peatland, a large, 28 km2, 5 m deep, raised ombro-oligotrophic, shrub and Sphagnum covered bog, near Ottawa, Canada from May 1, 1998 until the present. The sixteen-year daily CO2, CH4, and DOC flux and NECB covers a wide range of variability in peatland water storage from very dry to very wet growing seasons. We used the MB data to test the extent of MB peatland’s stability and the strength of the underlying key feedback between the NECB and changes in water storage projected by the models. In 2007 we published a six-year (1999-2004) net ecosystem carbon balance (NECB) for MB of ∼22 ± 40 g C m-2 yr-1, but we have since recalculated the 1998-2004 NECB to be 32 ± 40 g C m-2 yr-1 based on a reanalyzed average NEP of 51 ± 41 g C m-2 yr-1. Over the same period the net loss of C via the CH4 and DOC fluxes were -4 ± 1 and -15 ± 3 g C m-2 yr-1. The 1998-2004 six-year MB average NECB is similar to the long-term C accumulation rate, estimated from MB peat cores, for the last 3,000 years. The post 2004 MB NEP has increased to an average of ∼96 ± 32 g C m-2 yr-1 largely to there being generally wetter growing seasons. The losses of C via DOC (18 ± 1 g C m-2 yr-1) and CH4 (7 ± 4 g C m-2 yr-1) while showing considerable year-to-year variability are not significantly different post 2004. Hence, the proportional loss of C as DOC and CH4 in the MB NECB is slightly less post-2004 than it was before 2004 though the cumulative errors preclude statistically differences. As a result the MB NECB has increased to 79 ± 29 g C m-2 yr-1 post 2004 yielding a 14 year contemporary NECB of 56 ± 36 g C m-2 yr-1, which is double the long-term accumulation rate of C. The variability in the annual NECB and growing season mean NEP for the MB bog can be explained (r2 = 0.35, p \u3c 0.01) by the variability in growing season water table depth. These results suggest the carbon balance – water table feedback is sufficient enough to create stability in continental bogs so they will withstand a considerable amount of climate change

Immunologic activation of human syncytiotrophoblast by Plasmodium falciparum

<p>Abstract</p> <p>Background</p> <p>Malaria during pregnancy is characterized by the sequestration of malaria-infected red blood cells (iRBC) in the intervillous spaces of the placenta, often accompanied by the infiltration of maternal mononuclear cells, causing substantial maternal and foetal/infant morbidity. The iRBC bind to receptors expressed by the syncytiotrophoblast (ST). How ST responds to this interaction remains poorly understood. Because it is known that ST is immunoactive and can respond to infectious agents, the consequences of this ST-iRBC interaction should be investigated.</p> <p>Methods</p> <p>An in vitro system was used to assess the biochemical and immunological changes induced in ST by ST-adherent iRBCs. Changes in ST mitogen-activated protein kinase (MAPK) activation were assessed by immunoblotting and mRNA expression levels of selected cytokine and chemokines in primary ST bound by iRBC were determined using real-time, reverse transcription PCR. In addition, secreted cytokine and chemokine proteins were assayed by standard ELISA, and chemotaxis of PBMC was assessed using a two-chamber assay system.</p> <p>Results</p> <p>Following iRBC/ST interaction, ST C-Jun N-terminal kinase 1 (JNK1) was activated and modest increases in the mRNA expression of TGF-β and IL-8/CXCL8 were observed. In addition, this interaction increased secretion of MIF and MIP-1α/CCL3 by ST and induced migration of PBMC towards iRBC-stimulated ST.</p> <p>Conclusion</p> <p>Results from this study provide the first evidence that ST participates in shaping the local immunological milieu and in the recruitment of maternal immune cells to the maternal blood space during placental malaria infection.</p

Simulated and experimental estimates of hydrodynamic drag from bioâ logging tags

Drag force acting on swimming marine mammals is difficult to measure directly. Researchers often use simple modeling and kinematic measurements from animals, or computational fluid dynamics (CFD) simulations to estimate drag. However, studies that compare these methods are lacking. Here, computational simulation and physical experiments were used to estimate drag forces on gliding bottlenose dolphins (Tursiops truncatus). To facilitate comparison, variable drag loading (noâ tag, tag, tagâ +â 4, tagâ +â 8) was used to increase force in both simulations and experiments. During the experiments, two dolphins were trained to perform controlled glides with variable loading. CFD simulations of dolphin/tag geometry in steady flow (1â 6â m/s) were used to model drag forces. We expect both techniques will capture relative changes created by experimental conditions, but absolute forces predicted by the methods will differ. CFD estimates were within a calculated 90% confidence interval of the experimental results for all but the tag condition. Relative drag increase predicted by the simulation vs. experiment, respectively, differed by between 21% and 31%: tag, 4% vs. 33%; tagâ +â 4, 47% vs. 68%; and tagâ +â 8, 108% vs. 77%. The results from this work provide a direct comparison of computational and experimental estimates of drag, and provide a framework to quantify uncertainty.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152630/1/mms12627.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152630/2/mms12627_am.pd

Targeted muscle reinnervation for the management of pain in the setting of major limb amputation

The life altering nature of major limb amputations may be further complicated by neuroma formation in up to 60% of the estimated 2 million major limb amputees in the United States. This can be a source of pain and functional limitation of the residual limb. Pain associated with neuromas may limit prosthetic limb use, require reoperation, lead to opioid dependence, and dramatically reduce quality of life. A number of management options have been described including excision alone, excision with repair, excision with transposition, and targeted muscle reinnervation. Targeted muscle reinnervation has been shown to reduce phantom limb and neuroma pain for patients with upper and lower extremity amputations. It may be performed at the time of initial amputation to prevent pain development or secondarily for the treatment of established pain. Encouraging outcomes have been reported, and targeted muscle reinnervation is emerging as a leading surgical technique for pain prevention in patients undergoing major limb amputations and pain management in patients with pre-existing amputations

Sequence Polymorphism, Segmental Recombination and Toggling Amino Acid Residues within the DBL3X Domain of the VAR2CSA Placental Malaria Antigen

Plasmodium falciparum malaria remains one of the world's foremost health problems, primarily in highly endemic regions such as Sub-Saharan Africa, where it is responsible for substantial morbidity, mortality and economic losses. Malaria is a significant cause of severe disease and death in pregnant women and newborns, with pathogenesis being associated with expression of a unique variant of the multidomain Plasmodium falciparum Erythrocyte Membrane Protein 1 (PfEMP1) called VAR2CSA. Here, we characterize the polymorphism of the DBL3X domain of VAR2CSA and identify regions under selective pressure among placental parasites from women living in endemic western Kenya. In addition to significant levels of polymorphism, our analysis reveals evidence for diversification through intra-segmental recombination and novel mutations that likely contributed to the high number of unique VAR2CSA sequence types identified in this study. Interestingly, we also identified a number of critical residues that may be implicated in immune evasion through switching (or toggling) to alternative amino acids, including an arginine residue within the predicted binding pocket in subdomain III, which was previously implicated in binding to placental CSA. Overall, these findings are important for understanding parasite diversity in pregnant women and will be useful for identifying epitopes and variants of DBL3X to be included in a vaccine against placental malaria

Assessment of hemodynamic indices of conjunctival microvascular function in patients with coronary microvascular dysfunction

Objective: Coronary microvascular dysfunction (CMD) is a cause of ischaemia with non-obstructive coronary arteries (INOCA). It is notoriously underdiagnosed due to the need for invasive microvascular function testing. We hypothesized that systemic microvascular dysfunction could be demonstrated non-invasively in the microcirculation of the bulbar conjunctiva in patients with CMD. Methods: Patients undergoing coronary angiography for the investigation of chest pain or dyspnoea, with physiologically insignificant epicardial disease (fractional flow reserve ≥0.80) were recruited. All patients underwent invasive coronary microvascular function testing. We compared a cohort of patients with evidence of CMD (IMR ≥25 or CFR &lt;2.0); to a group of controls (IMR &lt;25 and CFR ≥2.0). Conjunctival imaging was performed using a previously validated combination of a smartphone and slit-lamp biomicroscope. This technique allows measurement of vessel diameter and other indices of microvascular function by tracking erythrocyte motion. Results: A total of 111 patients were included (43 CMD and 68 controls). There were no differences in baseline demographics, co-morbidities or epicardial coronary disease severity. The mean number of vessel segments analysed per patient was 21.0 ± 12.8 (3.2 ± 3.5 arterioles and 14.8 ± 10.8 venules). In the CMD cohort, significant reductions were observed in axial/cross-sectional velocity, blood flow, wall shear rate and stress. Conclusion: The changes in microvascular function linked to CMD can be observed non-invasively in the bulbar conjunctiva. Conjunctival vascular imaging may have utility as a non-invasive tool to both diagnose CMD and augment conventional cardiovascular risk assessment.</p