16 research outputs found
It's about time: A synthesis of changing phenology in the Gulf of Maine ecosystem
Š The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Staudinger, M. D., Mills, K. E., Stamieszkin, K., Record, N. R., Hudak, C. A., Allyn, A., Diamond, A., Friedland, K. D., Golet, W., Henderson, M. E., Hernandez, C. M., Huntington, T. G., Ji, R., Johnson, C. L., Johnson, D. S., Jordaan, A., Kocik, J., Li, Y., Liebman, M., Nichols, O. C., Pendleton, D., Richards, R. A., Robben, T., Thomas, A. C., Walsh, H. J., & Yakola, K. It's about time: A synthesis of changing phenology in the Gulf of Maine ecosystem. Fisheries Oceanography, 28(5), (2019): 532-566, doi: 10.1111/fog.12429.The timing of recurring biological and seasonal environmental events is changing on a global scale relative to temperature and other climate drivers. This study considers the Gulf of Maine ecosystem, a region of high social and ecological importance in the Northwest Atlantic Ocean and synthesizes current knowledge of (a) key seasonal processes, patterns, and events; (b) direct evidence for shifts in timing; (c) implications of phenological responses for linked ecologicalâhuman systems; and (d) potential phenologyâfocused adaptation strategies and actions. Twenty studies demonstrated shifts in timing of regional marine organisms and seasonal environmental events. The most common response was earlier timing, observed in spring onset, spring and winter hydrology, zooplankton abundance, occurrence of several larval fishes, and diadromous fish migrations. Later timing was documented for fall onset, reproduction and fledging in Atlantic puffins, spring and fall phytoplankton blooms, and occurrence of additional larval fishes. Changes in event duration generally increased and were detected in zooplankton peak abundance, early life history periods of macroâinvertebrates, and lobster fishery landings. Reduced duration was observed in winterâspring iceâaffected stream flows. Two studies projected phenological changes, both finding diapause duration would decrease in zooplankton under future climate scenarios. Phenological responses were speciesâspecific and varied depending on the environmental driver, spatial, and temporal scales evaluated. Overall, a wide range of baseline phenology and relevant modeling studies exist, yet surprisingly few document longâterm shifts. Results reveal a need for increased emphasis on phenological shifts in the Gulf of Maine and identify opportunities for future research and consideration of phenological changes in adaptation efforts.This work was supported by the Department of the Interior Northeast Climate Adaptation Science Center (G14AC00441) for MDS, AJ, and KY; the National Science Foundation's Coastal SEES Program (OCEâ1325484) for KEM, ACT, MEH, and AA; the National Aeronautics and Space Administration (NNX16 AG59G) for ACT, KEM, NRR, and KSS; the USGS Climate Research and Development Program for TGH; National Science & Engineering Research Council of Canada, University of New Brunswick, Environment Canada, Sir James Dunn Wildlife Research Centre, and New Brunswick Wildlife Trust Fund for AD. We also thank the Regional Association for Research on the Gulf of Maine for support, and the Gulf of Maine Research Institute for hosting and providing in kind resources for a two day inâperson workshop in August 2016. We greatly appreciate contributions from K. Alexander, G. Calandrino, C. Feurt, I. Mlsna, N. Rebuck, J. Seavey, and J. Sun for helping shape the initial scope of the manuscript. We thank J. Weltzin and two anonymous reviewers for their constructive comments. The contents of this paper are solely the responsibility of the authors and do not necessarily represent the views of the Northeast Climate Adaptation Science Center, U.S. Geological Survey, National Oceanographic and Atmospheric Administration, Fisheries and Oceans Canada or the US Environmental Protection Agency. This manuscript is submitted for publication with the understanding that the United States Government is authorized to reproduce and distribute reprints for Governmental purposes. None of the authors have conflicts of interest to declare in association with the contents of this manuscript
Earnings Responses to Social Security Contributions
This paper exploits discontinuities induced by earnings caps for social security contributions (SSC) in Germany to analyse the effect of SSC on gross labour earnings. Empirical evidence is based on two complementary approaches utilising two administrative data sets. First, employment responses to SSC at the intensive margin are identified by a modified bunching approach that is applied to kinks in the budget set generated by the earnings caps. Second, I exploit an increase ofa regional earnings cap of health and long-term care insurance as a natural experiment. In order to analyse economic incidence a difference-in-differences approach is used to estimate the effects on gross earnings. I find employment responses to be negligible and the burden of SSC to be shared equally between employers and employees. Both results turn out to be robust and are consistent with a competitive labour market model
Unsymmetrical Bisquinolines with High Potency against P. falciparum Malaria
Quinoline-based scaffolds have been the mainstay of antimalarial drugs, including many artemisinin combination therapies (ACTs), over the history of modern drug development. Although much progress has been made in the search for novel antimalarial scaffolds, it may be that quinolines will remain useful, especially if very potent compounds from this class are discovered. We report here the results of a structure-activity relationship (SAR) study assessing potential unsymmetrical bisquinoline antiplasmodial drug candidates using in vitro activity against intact parasites in cell culture. Many unsymmetrical bisquinolines were found to be highly potent against both chloroquine-sensitive and chloroquine-resistant Plasmodium falciparum parasites. Further work to develop such compounds could focus on minimizing toxicities in order to find suitable candidates for clinical evaluation
Adverse Reactions in a Phase 1 Trial of the Anti-Malarial DM1157: An Example of Pharmacokinetic Modeling and Simulation Guiding Clinical Trial Decisions
Introduction: There is an urgent need to develop new drugs to treat malaria due to increasing resistance to first-line therapeutics targeting the causative organism, Plasmodium falciparum (P. falciparum). One drug candidate is DM1157, a small molecule that inhibits the formation of hemozoin, which protects P. falciparum from heme toxicity. We describe a first-in-human, phase 1 trial of DM1157 in healthy adult volunteers that was halted early because of significant toxicity.
Methods: Adverse events were summarized using descriptive statistics. We used pharmacokinetic modeling to quantitatively assess whether the DM1157 exposure needed for P. falciparum inhibition was achievable at safe doses.
Results: We found that there was no dose where both the safety and efficacy target were simultaneously achieved; conversely, the model predicted that 27 mg was the highest dosage at which patients would consistently maintain safe exposure with multiple dosing. By pre-defining dose escalation stopping rules and conducting an interim pharmacokinetic/pharmacodynamic analysis, we determined that the study would be unable to safely achieve a dosage needed to observe an anti-malarial effect, thereby providing strong rationale to halt the study.
Conclusion: This study provides an important example of the risks and challenges of conducting early phase research as well as the role of modeling and simulation to optimize participant safety (ClinicalTrials.gov, NCT03490162)
New Scalable Synthetic Routes to ELQ-300, ELQ-316, and Other Antiparasitic Quinolones
The endochin-like quinolone (ELQ) compound class may yield effective, safe treatments for a range of important human and animal afflictions. However, to access the public health potential of this compound series, a synthetic route needed to be devised, which would lower costs and be amenable to large-scale production. In the new synthetic route described here, a substituted β-keto ester, formed by an Ullmann reaction and subsequent acylation, is reacted with an aniline via a ConradâLimpach reaction to produce 3-substituted 4(1H)-quinolones such as ELQ-300 and ELQ-316. This synthetic route, the first described to be truly amenable to industrial-scale production, is relatively short (five reaction steps), does not require palladium, chromatographic separation, or protecting group chemistry, and may be performed without high vacuum distillation