3,393 research outputs found
The Legionella pneumophila IcmSW Complex Interacts with Multiple Dot/Icm Effectors to Facilitate Type IV Translocation
Many Gram-negative pathogens use a type IV secretion system (T4SS) to deliver effector proteins into eukaryotic host cells. The fidelity of protein translocation depends on the efficient recognition of effector proteins by the T4SS. Legionella pneumophila delivers a large number of effector proteins into eukaryotic cells using the Dot/Icm T4SS. How the Dot/Icm system is able to recognize and control the delivery of effectors is poorly understood. Recent studies suggest that the IcmS and IcmW proteins interact to form a stable complex that facilitates translocation of effector proteins by the Dot/Icm system by an unknown mechanism. Here we demonstrate that the IcmSW complex is necessary for the productive translocation of multiple Dot/Icm effector proteins. Effector proteins that were able to bind IcmSW in vitro required icmS and icmW for efficient translocation into eukaryotic cells during L. pneumophila infection. We identified regions in the effector protein SidG involved in icmSW-dependent translocation. Although the full-length SidG protein was translocated by an icmSW-dependent mechanism, deletion of amino terminal regions in the SidG protein resulted in icmSW-independent translocation, indicating that the IcmSW complex is not contributing directly to recognition of effector proteins by the Dot/Icm system. Biochemical and genetic studies showed that the IcmSW complex interacts with a central region of the SidG protein. The IcmSW interaction resulted in a conformational change in the SidG protein as determined by differences in protease sensitivity in vitro. These data suggest that IcmSW binding to effectors could enhance effector protein delivery by mediating a conformational change that facilitates T4SS recognition of a translocation domain located in the carboxyl region of the effector protein
Healthy diets can create environmental trade-offs, depending on how diet quality is measured
Background: There is an urgent need to assess the linkages between diet patterns and environmental sustainability in order to meet global targets for reducing premature mortality and improving sustainable management of natural resources. This study fills an important research gap by evaluating the relationship between incremental differences in diet quality and multiple environmental burdens, while also accounting for the separate contributions of retail losses, inedible portions, and consumer waste. Methods: Cross sectional, nationally-representative data on food intake in the United States were acquired from the National Health and Nutrition Examination Survey (2005â2016), and were linked with nationally-representative data on food loss and waste from published literature. Survey-weighted procedures estimated daily per capita food retail loss, food waste, inedible portions, and consumed food, and were summed to represent Total Food Demand. Diet quality was measured using the Healthy Eating Index-2015 and the Alternative Healthy Eating Index-2010. Data on food intake, loss, and waste were inputted into the US Foodprint Model to estimate the amount of agricultural land, fertilizer nutrients, pesticides, and irrigation water used to produce food. Results: This study included dietary data from 50,014 individuals aged â„2 y. Higher diet quality (HEI-2015 and AHEI-2010) was associated with greater per capita Total Food Demand, as well as greater retail loss, inedible portions, consumer waste, and consumed food (P \u3c 0.001 for all comparisons). Consumed food accounted for 56â74% of agricultural resource use (land, fertilizer nutrients, pesticides, and irrigation water), retail loss accounted for 4â6%, inedible portions accounted for 2â15%, and consumer waste accounted for 20â23%. Higher diet quality was associated with lower use of agricultural land, but the relationship to other agricultural resources was dependent on the tool used to measure diet quality (HEI-2015 vs. AHEI-2010). Conclusions: Over one-quarter of the agricultural inputs used to produce Total Food Demand were attributable to edible food that was not consumed. Importantly, this study also demonstrates that the relationship between diet quality and environmental sustainability depends on how diet quality is measured. These findings have implications for the development of sustainable dietary guidelines, which requires balancing population-level nutritional needs with the environmental impacts of food choices
US county-level agricultural crop production typology
Objectives: Crop production is an important variable in social, economic and environmental analyses. There is an abundance of crop data available for the United States, but we lack a typology of county-level crop production that accounts for production similarities in counties across the country. We fill this gap with a county-level classification of crop production with ten mutually exclusive categories across the contiguous United States. Data description: To create the typology we ran a cluster analysis on acreage data for 21 key crops from the United States Department of Agriculture\u27s 2012 Agricultural Census. Prior to clustering, we estimated undisclosed county acreage values, controlled for acreage in other crop types, and removed counties with low agricultural production to produce proportional scores for each crop type in each county. We used proportional scores to control for the influence of county size in the cluster analysis and used internal and stability measures to validate the analysis. The final dataset features 2922 counties. Future research can leverage this typology as an input for county- or regional-level analysis
Transient social-ecological stability: The effects of invasive species and ecosystem restoration on nutrient management compromise in lake erie
Together, lake ecosystems and local human activity form complex social-ecological systems (SESs) characterized by feedback loops and discontinuous change. Researchers in diverse fields have suggested that complex systems do not have single stable equilibria in the long term because of inevitable perturbation. During this study, we sought to address the general question of whether or not stable social-ecological equilibria exist in highly stressed and managed lacustrine systems. Using an integrated human-biophysical model, we investigated the impacts of a species invasion and ecosystem restoration on SES equilibrium, defined here as a compromise in phosphorus management among opposing stakeholders, in western Lake Erie. Our integrated model is composed of a calibrated ecological submodel representing Sandusky Bay, and a phosphorus management submodel that reflects the societal benefits and costs of phosphorus regulation. These two submodels together form a dynamic feedback loop that includes freshwater ecology, ecosystem services, and phosphorus management. We found that the invasion of dreissenid mussels decreased ecosystem resistance to eutrophication, necessitating increased phosphorus management to preserve ecosystem services and thus creating the potential for a shift in social-ecological equilibrium. Additionally, our results suggest that net benefits in the region following the invasion of dreissenids may never again reach the pre-invasion level if on-site phosphorus control is the sole management lever. Further demonstrating transient system stability, large-scale wetland restoration shifted points of management compromise to states characterized by less on-site phosphorus management and higher environmental quality, resulting in a significant increase in net benefits in the region. We conclude that lacustrine SESs are open and dynamic, and we recommend that future models of these systems emphasize site-specific perturbation over equilibrium, thereby aiding the development of management plans for building system resistance to undesirable change that are both flexible and sustainable in an unknowable future. © 2010 by the author(s)
Age Deficits in Facial Affect Recognition : The Influence of Dynamic Cues
Funding This work was supported by the Australian Research Council, Australia (DP150100302) and the Leverhulme Trust, U.K. (F/00152/W).Peer reviewedPostprin
Quarkonium Wave Functions at the Origin
We tabulate values of the radial Schr\"{o}dinger wave function or its first
nonvanishing derivative at zero quark-antiquark separation, for ,
, and levels that lie below, or just above, flavor
threshold. These quantities are essential inputs for evaluating production
cross sections for quarkonium states.Comment: 9 pages, RevTeX, no figure
Relationship between food waste, diet quality, and environmental sustainability
Improving diet quality while simultaneously reducing environmental impact is a critical focus globally. Metrics linking diet quality and sustainability have typically focused on a limited suite of indicators, and have not included food waste. To address this important research gap, we examine the relationship between food waste, diet quality, nutrient waste, and multiple measures of sustainability: use of cropland, irrigation water, pesticides, and fertilizers. Data on food intake, food waste, and application rates of agricultural amendments were collected from diverse US government sources. Diet quality was assessed using the Healthy Eating Index-2015. A biophysical simulation model was used to estimate the amount of cropland associated with wasted food. This analysis finds that US consumers wasted 422g of food per person daily, with 30 million acres of cropland used to produce this food every year. This accounts for 30% of daily calories available for consumption, one-quarter of daily food (by weight) available for consumption, and 7% of annual cropland acreage. Higher quality diets were associated with greater amounts of food waste and greater amounts of wasted irrigation water and pesticides, but less cropland waste. This is largely due to fruits and vegetables, which are health-promoting and require small amounts of cropland, but require substantial amounts of agricultural inputs. These results suggest that simultaneous efforts to improve diet quality and reduce food waste are necessary. Increasing consumersâ knowledge about how to prepare and store fruits and vegetables will be one of the practical solutions to reducing food waste
Developing Metrics for Novel Value-Added Products: The Case of Hemp in Vermont
Vermont Farm to Plate 2020 identifies hemp as one of ten emergent agricultural products critical for Vermontâs future and has made recommendations for investments in hemp research, education, feasibility, and innovation programs. These investments are essential to develop niche food, feed, fiber, and industrial products, professionals, and markets that go âbeyond CBDâ (VFP, 2020).
This project develops indicators for an important, value added budding crop in Vermont: hemp. For the purposes of this white paper, indicators are âa way to measure, indicate or point to with more or less exactness,â or âsomething used to show the condition of a systemâ (Feenstra et al., 2005). We focus on the example of hemp to illustrate how emerging value-added crops contribute to sustainable food systems. We use a set of design principles to ensure the applicability of developed indicators for decision making. This framework, its processes, and measures, are transferable to any nascent crop for evaluating economic, environmental, and social sustainability.
Our objectives are to: Develop a set of indicators to measure the economic, social, and environmental inputs of hemp in Vermont. Identify techniques and data sources for mining hemp metrics. Evaluate the hierarchical levels of mined data and transecting indicators to inform growing discussions of metric integration and forecasting agricultural food sustainability.
Our approach is grounded in the FAO food systems model, Doughnut Economics, which uses the UN Sustainable Development Goals as a foundation to describe âsocial floorsâ and planetary boundaries, and the concepts of seven community capitals: political, cultural, human, social, financial, built, and environmental. Our work plan included a two-day virtual workshop with required reading prior to the event, and involved both University researchers and stakeholders representing production, industry, finance, government, and NGOs.
We describe 35 metrics to assess the sustainability of hemp in the Vermont economy, environment and community going forward (Figure 2 and Table 1).
We also make several recommendations to move the collection of food system metrics forward. General recommendations include: Farmer surveys to specifically address challenges facing farmers growing a novel crop. In hemp this is particularly important, as the crop attracts many who are new to farming, and no one has been able to legally grow it at field scale in the US for the past several generations. Community/consumer surveys to collect data on community needs and impacts of novel value added crops (hemp) Collection and curation of spatial data tied to appropriate metrics Allocation of ARS funds for at least one data professional with skills across data types and methods, including individual, spatial, community level, etc. Funds to build out nutrient mass balance and soil carbon stock models for different soil types and production approaches The use of a grower-friendly tracking App with incentives (GoCrop) Development of a dashboard to easily visualize direction and degree of movement toward a desired state
We make more specific recommendations in the Appendix where each metric is described in detail
Color-Octet Fragmentation and the psi' Surplus at the Tevatron
The production rate of prompt 's at large transverse momentum at the
Tevatron is larger than theoretical expectations by about a factor of 30. As a
solution to this puzzle, we suggest that the dominant production
mechanism is the fragmentation of a gluon into a pair in a pointlike
color-octet S-wave state, which subsequently evolves nonperturbatively into a
plus light hadrons. The contribution to the fragmentation function from
this process is enhanced by a short-distance factor of relative
to the conventional color-singlet contribution. This may compensate for the
suppression by , where is the relative momentum of the charm quark in
the . If this is indeed the dominant production mechanism at large
, then the prompt 's that are observed at the Tevatron should
almost always be associated with a jet of light hadrons.Comment: 9 pages, LaTe
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