Mehlotra R.K.,Case Western Reserve University |
Hall N.B.,Case Western Reserve University |
Bruse S.E.,Case Western Reserve University |
Bruse S.E.,Regeneron Pharmaceuticals Inc |
And 6 more authors.
Infection, Genetics and Evolution | Year: 2015
Polymorphisms in chemokine receptors, serving as HIV co-receptors, and their ligands are among the well-known host genetic factors associated with susceptibility to HIV infection and/or disease progression. Papua New Guinea (PNG) has one of the highest adult HIV prevalences in the Asia-Pacific region. However, information regarding the distribution of polymorphisms in chemokine receptor (CCR5, CCR2) and chemokine (CXCL12) genes in PNG is very limited. In this study, we genotyped a total of nine CCR2-CCR5 polymorphisms, including CCR2 190G > A, CCR5 - 2459G > A and δ32, and CXCL12 801G > A in PNG (n = 258), North America (n = 184), and five countries in West Africa (n = 178). Using this data, we determined previously characterized CCR5 haplotypes. In addition, based on the previously reported associations of CCR2 190, CCR5 - 2459, CCR5 open reading frame, and CXCL12 801 genotypes with HIV acquisition and/or disease progression, we calculated composite full risk scores, considering both protective as well as susceptibility effects of the CXCL12 801 AA genotype. We observed a very high frequency of the CCR5 - 2459A allele (0.98) in the PNG population, which together with the absence of δ32 resulted in a very high frequency of the HHE haplotype (0.92). These frequencies were significantly higher than in any other population (all P-values < 0.001). Regardless of whether we considered the CXCL12 801 AA genotype protective or susceptible, the risk scores were significantly higher in the PNG population compared with any other population (all P-values < 0.001). The results of this study provide new insights regarding CCR5 variation in the PNG population, and suggest that the collective variation in CCR2, CCR5, and CXCL12 may increase the risk of HIV/AIDS in a large majority of Papua New Guineans. © 2015 Elsevier B.V.
Gunn J.S.,Initiative Capital |
Saah D.S.,Spatial Informatics Group |
Hagan J.M.,Manomet Center for Conservation science
Journal of Sustainable Forestry | Year: 2013
Policies based on assumed carbon neutrality fail to address the timing and magnitude of the net greenhouse gas (GHG) changes from using wood for energy. We present a "debt-then-dividend" framework for evaluating the temporal GHG impacts of burning wood for energy. We also present a case study conducted in Massachusetts, USA to demonstrate the framework. Four key inputs are required to calculate the specific shape of the debt-then-dividend curve for a given region or individual biomass facility. First, the biomass feedstock source: the GHG implications of feedstocks differ depending on what would have happened to the material in the absence of biomass energy generation. Second, the form of energy generated: energy technologies have different generation efficiencies and thus different life cycle GHG emissions profiles. Third, the fossil fuel displaced: coal, oil, and natural gas each have different emissions per unit of energy produced. Fourth, the management of the forest: forest management decisions affect recovery rates of carbon from the atmosphere. This framework has broad application for informing the development of renewable energy and climate policies. Most importantly, this debt-then-dividend framework explicitly recognizes that GHG benefits of wood biomass energy will be specific to the forest and technology context of the region or biomass energy projects. © 2013 Copyright Taylor and Francis Group, LLC.
Chan K.M.A.,University of British Columbia |
Ruckelshaus M.,Initiative Capital
F1000 Biology Reports | Year: 2010
The benefits of marine ecosystems for people are increasingly being characterized through the concept of ecosystem services, with the promise to aid decision making from marine spatial planning to ecosystem-based management. The characterization of changes in marine ecosystem services is central to the application of ecological science to policy contexts, and this field is quickly evolving with innovations in frameworks for integrating science, understanding of ecosystems and human benefits, and innovations in tools for the modeling of services. In this article, we review efforts to characterize changes in marine ecosystem services, including recent advances, and we propose five key future directions for research: cultural values, qualitative or semi-quantitative modeling approaches, cumulative impacts, model evaluation, and markets. © 2010 Faculty of 1000 Ltd.
Gunn J.S.,Initiative Capital |
Ganz D.J.,Lowering Emissions in Asias Forests LEAF |
Keeton W.S.,University of Vermont
GCB Bioenergy | Year: 2012
In the current debate over the CO2 emissions implications of switching from fossil fuel energy sources to include a substantial amount of woody biomass energy, many scientists and policy makers hold the view that emissions from the two sources should not be equated. Their rationale is that the combustion or decay of woody biomass is simply part of the global cycle of biogenic carbon and does not increase the amount of carbon in circulation. This view is frequently presented as justification to implement policies that encourage the substitution of fossil fuel energy sources with biomass. We present the opinion that this is an inappropriate conceptual basis to assess the atmospheric greenhouse gas (GHG) accounting of woody biomass energy generation. While there are many other environmental, social, and economic reasons to move to woody biomass energy, we argue that the inferred benefits of biogenic emissions over fossil fuel emissions should be reconsidered. © 2011 Blackwell Publishing Ltd.
Gunn J.S.,Initiative Capital |
Saah D.S.,Spatial Informatics Group LLC |
Fernholz K.,Dovetail |
Ganz D.J.,Nature Conservancy
Forest Science | Year: 2011
We evaluated the implications of area regulation of harvest on eligible carbon under both the Voluntary Carbon Standard (VCS) and the Chicago Climate Exchange (CCX) for public forest lands in north central Minnesota (89,840 ha total). We used data from the carbon submodel of the US Forest Service Forest Vegetation Simulator (Lake States variant) to evaluate changes in forest carbon stocks under different management scenarios. Baseline harvest intensity was defined by considering the manager's short-range tactical plans and the distribution of harvests by cover type and intensity class then became the "business as usual" (BAU) for use in the calculation of eligible carbon under the VCS and CCX. Under VCS, the most effective way to increase carbon stocks while meeting other management objectives was to shift harvest practices to lower intensity entries and retain higher residual basal areas. The carbon stock change rates for each manager varied significantly under the BAU scenario and resulted in a mean annual net decrease. Because CCX carbon credit eligibility requires a net increase of carbon stocking from the base year, area regulation may create periods of time where there is no eligible carbon volume. An alternate management strategy that uses the area regulation method, reduces harvest intensity, and decreases overall acreage harvested was able to provide higher postharvest carbon stocks versus the BAU scenario under VCS. © 2011 by the Society of American Foresters.