519 research outputs found
Impacts of the US Ethanol Boom in Rural Mexico
Assessing the human and environmental impacts of biofuels requires unraveling the connection between international trade, on one hand, and local land-use and social change, on the other, while accounting for cross-scalar linkages between and within social and environmental systems. We propose a disaggregated approach to model how macro shocks shape rural households’ decisions, and how these decisions integrate onto aggregate supply and land use patterns. The approach, built on an agent-based model of rural Mexico, is used to explore the impacts of ethanol-driven US corn price increases. Our estimate of a 5.7% expansion in corn area by 2008 and wide variation across regions corresponds fairly well with ex post reports. Estimates from alternative models exceed ours by up to 200%. Corn land expanded between 1.6% in the southeast and 16% in the northwest. A 3% increase in agricultural value added nevertheless did not promote rural development, whether measured in terms of total rural value added or income. Direct and indirect (multiplier) effects on rural incomes were limited. Rural households experienced a 0.02% increase in real income, while absentee (non-rural) landholders’ income increased 3.9%. Our approach highlights the crucial role of local market conditions and interactions among microeconomic actors in shaping biofuels’ impacts via local feedback mechanisms. It suggests that subsistence activities might keep deforestation pressures in check in some developing areas while precluding the rural population from benefiting. A disaggregated approach should help integrate future research on land-use change and economics.Crop Production/Industries,
Helminths of \u3ci\u3ePeromyscus leucopus\u3c/i\u3e, \u3ci\u3eP. maniculatus\u3c/i\u3e, and \u3ci\u3eBlarina carolinensis\u3c/i\u3e from Southern Illinois
Helminths were recovered from 12 (12%) of 100 deer mice (Peromyscus maniculatus) and 26 (24%) of 109 white-footed mice (P. leucopus) collected in 16 counties of southern Illinois. Helminths from deer mice included Choanotaenia peromysci (7.0%), Hymenolepis bennetti (2.0%), Postharmostomum helicis (1.0%), Physaloptera sp. (1.0%), Rictularia coloradensis (1.0%) and Moniliformis clarki (1.0%). Hymenolepis bennetti (1.8%), Physaloptera sp. (4.6%), and Rictularia coloradensis (20.0%) occurred in white-footed mice. C. peromysci and R. coloradensis revealed a high degree of host-specificity and along with Physaloptera showed some degree of habitat dependence. Infection rates were highest during the summer. Thirteen (65%) of 20 southern short-tailed shrews (Blarina carolinensis) were infected with Cryptocotylepis anthocephalus (40.0%), Brachylaima thompsoni (20.0%), Panopistus pricei (15.0%), Capillaria sp. (15.0%), Porrocaecum ensicaudatum (10.0%) and Porracaecum sp. (10.0%)
Helminths of the Gastrointestinal Tract of Raccoons in Southern Illinois with Management Implications of \u3ci\u3eBaylisascaris procyonis\u3c/i\u3e Occurrence
The gastrointestinal tracts of 60 raccoons (Procyon lotor) were examined for helminths. Six species were found: four species of nematodes (Arthrocephalus lotoris, Physaloptera rara, Gnathostoma procyonis, and Baylisascaris procyonis); one species of cestode (Mesocestoides variabilis); and one species of acanthocephalan (Macracanthorhynchus ingens). Baylisascaris procyonis has been implicated in the decline of woodrat populations throughout the northeast United States. As such, this parasite also may have been a factor in the extirpation of the eastern woodrat (Neotoma floridana) throughout most of southern Illinois. The frequency occurrence of Baylisascaris procyonis in our sample was unexpectedly low, 3 of 60 raccoons (5.0%), and suggests that reintroduction of eastern woodrats to formerly occupied sites in southern Illinois may not be adversely affected by this parasite
Implementation and performance of SIBYLS: a dual endstation small-angle X-ray scattering and macromolecular crystallography beamline at the Advanced Light Source.
The SIBYLS beamline (12.3.1) of the Advanced Light Source at Lawrence Berkeley National Laboratory, supported by the US Department of Energy and the National Institutes of Health, is optimized for both small-angle X-ray scattering (SAXS) and macromolecular crystallography (MX), making it unique among the world's mostly SAXS or MX dedicated beamlines. Since SIBYLS was commissioned, assessments of the limitations and advantages of a combined SAXS and MX beamline have suggested new strategies for integration and optimal data collection methods and have led to additional hardware and software enhancements. Features described include a dual mode monochromator [containing both Si(111) crystals and Mo/B(4)C multilayer elements], rapid beamline optics conversion between SAXS and MX modes, active beam stabilization, sample-loading robotics, and mail-in and remote data collection. These features allow users to gain valuable insights from both dynamic solution scattering and high-resolution atomic diffraction experiments performed at a single synchrotron beamline. Key practical issues considered for data collection and analysis include radiation damage, structural ensembles, alternative conformers and flexibility. SIBYLS develops and applies efficient combined MX and SAXS methods that deliver high-impact results by providing robust cost-effective routes to connect structures to biology and by performing experiments that aid beamline designs for next generation light sources
Dispersal of transgenes through maize seed systems in Mexico.
ObjectivesCurrent models of transgene dispersal focus on gene flow via pollen while neglecting seed, a vital vehicle for gene flow in centers of crop origin and diversity. We analyze the dispersal of maize transgenes via seeds in Mexico, the crop's cradle.MethodsWe use immunoassays (ELISA) to screen for the activity of recombinant proteins in a nationwide sample of farmer seed stocks. We estimate critical parameters of seed population dynamics using household survey data and combine these estimates with analytical results to examine presumed sources and mechanisms of dispersal.ResultsRecombinant proteins Cry1Ab/Ac and CP4/EPSPS were found in 3.1% and 1.8% of samples, respectively. They are most abundant in southeast Mexico but also present in the west-central region. Diffusion of seed and grain imported from the United States might explain the frequency and distribution of transgenes in west-central Mexico but not in the southeast.ConclusionsUnderstanding the potential for transgene survival and dispersal should help design methods to regulate the diffusion of germplasm into local seed stocks. Further research is needed on the interactions between formal and informal seed systems and grain markets in centers of crop origin and diversification
Global sexual fertility in the opportunistic pathogen aspergillus fumigatus and identification of new supermater strains
© 2020 by the authors. Licensee MDPI, Basel, Switzerland. A sexual cycle in Aspergillus fumigatus was first described in 2009 with isolates from Dublin, Ireland. However, the extent to which worldwide isolates can undergo sexual reproduction has remained unclear. In this study a global collection of 131 isolates was established with a near 1:1 ratio of mating types. All isolates were crossed to MAT1-1 or MAT1-2 Irish strains, and a subset of isolates from different continents were crossed together. Ninety seven percent of isolates were found to produce cleistothecia with at least one mating partner, showing that sexual fertility is not limited to the Irish population but is a characteristic of global A. fumigatus. However, large variation was seen in numbers of cleistothecia produced per cross, suggesting differences in the possibility for genetic exchange between strains in nature. The majority of crosses produced ascospores with >50% germination rates, but with wide variation evident. A high temperature heat shock was required to induce ascospore germination. Finally, a new set of highly fertile MAT1-1 and MAT1-2 supermater strains were identified and pyrimidine auxotrophs generated for community use. Results provide insights into the potential for the A. fumigatus sexual cycle to generate genetic variation and allow gene flow of medically important traits
Computationally Assisted Identification of Functional Inorganic Materials
Modules of Desire
Using computational methods to design materials with specific properties has found some limited success.
Dyer
et al.
(p.
847
, published online 11 April) have devised a method, based on extended module materials assembly, that combines chemical intuition and
ab initio
calculations starting from fragments or modules of structure types that show the desired functionality. The method was tested by identifying materials suitable for a solid oxide fuel cell cathode.
</jats:p
Efficacy of venetoclax monotherapy in patients with relapsed, refractory mantle cell lymphoma post BTK inhibitor therapy
- …