2,045 research outputs found

    The sustainability of tropical maize as an alternative biofuel or silage crop

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    With increasing world population, the U.S. Department of Energy initiated the Energy Independence and Security Act (EISA) requiring by 2030 the replacement of 30% of petroleum based fuel sources with biofuel (USDA 2010). Tropical maize (Zea mays L.) has potential as a new biofuel crop for the Midwestern US. It is a temperate by tropical (or tropical by tropical) hybrid that retains the photoperiod sensitivity of tropical materials when grown in temperate regions, resulting in high biomass, but with delayed flowering that reduces or eliminates grain production. The reduced grain production results in accumulation of sucrose in the stalk and a lower nitrogen fertilizer requirement. Our objective was to evaluate the impact of sustainable practices such as conservation tillage, cover crops, and reduced nitrogen fertilizer application on tropical maize as a biofuel, biomass, or animal feed crop. Tropical maize hybrids have been characterized as: 1) dual purpose, producing high biomass levels with high quality grain that can be harvested for the grain and the stover used in a bale-burning furnace for thermal energy, or that can be ensiled for use as animal feed; and 2) high sugar, producing high biomass and high stalk sugar accumulation that can be used for ethanol production. The experiment was conducted in Champaign, IL in 2014 and 2015. The two hybrid types were planted into tilled strips evaluated under three nitrogen rates of 0, 67 and 202 kg N ha-1. Two annual cover crops, annual ryegrass and pennycress, were compared to a perennial ground cover, creeping bentgrass, and a no-cover control. Annual cover crops produced tropical maize biomass yields similar to the no-cover control regardless of hybrid. Animal performance was similar when fed tropical maize grown at a lower rate of nitrogen compared to conventional field corn silage. Results show that a management system that optimizes the environmental sustainability of tropical maize can be used while maintaining a competitive yield

    A knowledge-based approach to automated flow-field zoning for computational fluid dynamics

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    An automated three-dimensional zonal grid generation capability for computational fluid dynamics is shown through the development of a demonstration computer program capable of automatically zoning the flow field of representative two-dimensional (2-D) aerodynamic configurations. The applicability of a knowledge-based programming approach to the domain of flow-field zoning is examined. Several aspects of flow-field zoning make the application of knowledge-based techniques challenging: the need for perceptual information, the role of individual bias in the design and evaluation of zonings, and the fact that the zoning process is modeled as a constructive, design-type task (for which there are relatively few examples of successful knowledge-based systems in any domain). Engineering solutions to the problems arising from these aspects are developed, and a demonstration system is implemented which can design, generate, and output flow-field zonings for representative 2-D aerodynamic configurations

    Managing the continuous corn yield penalty with crop and residue management

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    Corn (Zea mays L.) grown in rotation with soybean [Glycine max (L.) Merr.] generally yields more than corn grown continuously, with the latter designated the continuous corn yield penalty (CCYP). Due to global food security concerns and corn’s versatility in food products, animal feed, and biofuel/bioenergy feedstocks, production of corn must increase with the projected increasing world population. As a result, yield per area or the area in corn production must increase, which could result in more corn following corn acres. Primary causative factors contributing to the CCYP are soil nitrogen availability, residue accumulation, and the weather. Therefore, the objective of this research was to evaluate and determine management practices that could help relieve the yield penalty associated with production of continuous corn compared to when rotated with soybean. This research encompasses two research areas: What are the effects of hybrid selection, enhanced fertility, and population on corn yield and can these factors reduce the CCYP? Enhanced fertility improved grain yield across rotations and there was a 40 to 60% greater yield response to intensive management in continuous corn versus the corn-soybean rotation, suggesting intensified management as a method to mitigate the CCYP. With select hybrids, intensive management reduced the CCYP by 30 to 80%. Yield advantages to corn rotated with soybean were achieved through both more numerous and heavier kernels. Agronomic management and hybrid selection helped alleviate the CCYP demonstrating continuous corn can be managed for better productivity. Can the CCYP be alleviated by mechanical and chemical residue management in combination with an intensive agronomic input system? As grain yield level increased, stover biomass production increased, resulting in additional residue to be managed post-harvest, reinforcing the need to manage crop residue in not only continuous corn but also in high grain yield environments. Sizing down the stover material at harvest improved overwinter residue decomposition. Stress induced by continuous corn was not detected through crop assessments until the R2 reproductive stage. Intensive inputs resulted in additional early season above- and below-ground biomass compared to standard inputs and increased grain yield. Crop rotation, downsized residue, high input agronomic management, and hybrid selection all enhanced final grain yield

    Sunset haematology: improving the end-of-life journey for patients and caregivers, in patients with haematologic malignancies

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    BACKGROUND AND AIM Haematologic Malignancies (HM) are diverse diseases with differing illness trajectories and therapeutic pathways. Unfortunately HM patients may rapidly and unexpectedly clinically deteriorate, resulting in suboptimal engagement of palliative and end-of-life (EOL) care.  Compared to patients with solid tumours, HM patients have many different factors affecting their end-of-life (EOL) journey. Uniquely, a subset of HM patients with bone marrow failure (BMF) can be supported for significant, but highly variable, periods of time with red blood cell transfusions (RBCT), platelet transfusions (PT) and prophylactic antibiotics.  Availability of chronic RBCTs and PTs make HM patients with BMF similar to elderly and poor prognosis patients with end stage kidney disease (ESKD). Multidisciplinary Palliative Supportive Care programs have been shown to be effective for these EKSD patients and may serve as supportive care models for EOL journey in HM patients. This project is  a pilot study aiming to provide a template for management of EOL for patients with HM with BMF, and their care-givers. METHODS Three components are being developed: 1) Survey of patient opinions around treatment decision-making. 2) Analyses of the impact of patient, disease and treatment factors on the probability of survival from start of PT, to inform patients. 3) Collaborative involvement between Haematology and Palliative Care staff involved in the local ESKD program, to develop a template for earlier EOL pathway planning in HM patients. CONCLUSION Progress of work to date will be presented including preliminary findings and next steps

    Soil carbon respiration in tropical forest soils along geomorphic and geochemical gradients

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    Tropical ecosystems and the soils therein have been reported as one of the most important and largest terrestrial carbon (C) pools and are considered important climate regulator. Carbon stabilization mechanisms in these ecosystems are often complex, as these mechanisms crucially rely on the interplay of geology, topography, climate, and biology. Future predictions of the perturbation of the soil carbon pool ultimately depend on our mechanistic understanding of these complex interactions. Using laboratory incubation experiments, we investigated if carbon release from soils through heterotrophic respiration in the African highland forests of the Eastern Congo Basin follows predictable patterns related to topography, soil depth or geochemical soil properties that can be described at the landscape scale and ultimately be used to improve the spatial accuracy of soil C respiration in mechanistic models. In general, soils developed on basalt and granite parent material (mafic and felsic geochemistry of parent material) showed significantly (p <0.05) higher specific respiration than soils developed on sedimentary rocks (mixed geochemistry) with highest rates measured for soils developed on granite. For soils developed on basalt, specific respiration decreased two-fold with soil depth, but not for soils developed on granite or sedimentary rocks. No significant differences in respiration under tropical forest were found in relation to topography for any soil and geochemical background. Using a non-linear, stochastic gradient boosting machine learning approach we show that soil biological, physical and chemical properties can predict the pattern of specific soil respiration (R2=0.41, p<0.05). An assessment of the relative importance of the included predictors for soil respiration resulted in 43 % of the model being driven by geochemistry (pedogenic oxides, nutrient availability), 12 % driven by soil texture and clay mineralogy, 34 % by microbial biomass, C:N, and C:P ratios and 11 % by topographic indices. We conclude that, in order to explain soil C respiration patterns in tropical forests, a complex set of variables need to be considered that differs depending on the local bedrock chemistry. Its effect is likely related to the varying strength of C stabilization with minerals as well as nutrient availability that might drive C input patterns and microbial turnover

    Alternative reproductive tactics of unflanged and flanged male orangutans revisited

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    In many slowly developing mammal species, males reach sexual maturity well before they develop secondary sexual characteristics. Sexually mature male orangutans have exceptionally long periods of developmental arrest. The two male morphs have been associated with behavioral alternative reproductive tactics, but this interpretation is based on cross‐sectional analyses predominantly of Northwest Sumatran populations. Here we present the first longitudinal analyses of behavioral changes of 10 adult males that have been observed in both unflanged and flanged morph. We also analyzed long‐term behavioral data on an additional 143 individually identified males from two study sites, Suaq (Sumatra, Pongo abelii) and Tuanan (Borneo, Pongo pygmaeus wurmbii), to assess male mating tactics cross‐sectionally in relation to population, male morph (unflanged and flanged), and other socio‐ecological factors. Both our longitudinal and cross‐sectional results confirm and refine previous cross‐sectional accounts of the differences in mating tactics between the unflanged and the flanged male morphs. In the unflanged morph, males exhibit higher sociability, particularly with females, and higher rates of both copulation and sexual coercion than in the flanged morph. Based on our results and those of previous studies showing that females prefer flanged males, and that flanged males have higher reproductive success, we conclude that unflanged males face a trade‐off between avoiding male‐male contest competition and gaining mating access to females, and thus follow a “best‐of‐a‐bad‐job” mating strategy

    Problem solving and collaborative involvement among adolescents with spinal cord injury and their caregivers

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    ObjectiveTo determine the relationship between constructive adolescent problem solving (positive problem-solving orientation and rational problem-solving style) and caregiver problem solving and collaborative involvement with primary caregiver among adolescents with spinal cord injuries (SCIs). Positive constructive adolescent problem solving was hypothesized to be predicted by more effective caregiver problem solving and higher collaborative involvement.MethodsParticipants in this cross-sectional study were 79 adolescent and primary caregiver dyads recruited from a pediatric rehabilitation care system in North America. All participants completed a standardized problem-solving instrument and adolescent participants completed an adapted measure of collaborative parent involvement.ResultsMore effective caregiver problem solving and adolescent perceptions of more collaboration with caregivers around SCI care were significantly associated with higher positive problem-solving orientation and higher rational problem-solving style among adolescents.ConclusionsResults underscore the importance of caregiver problem-solving skills and their collaboration with adolescents with SCI when addressing care needs. Clinically, findings highlight opportunities for parent involvement and skill-building as an important factor of rehabilitation for adolescents with SCI

    Fine-mapping identifies multiple prostate cancer risk loci at 5p15, one of which associates with TERT expression

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    Associations between single nucleotide polymorphisms (SNPs) at 5p15 and multiple cancer types have been reported. We have previously shown evidence for a strong association between prostate cancer (PrCa) risk and rs2242652 at 5p15, intronic in the telomerase reverse transcriptase (TERT) gene that encodes TERT. To comprehensively evaluate the association between genetic variation across this region and PrCa, we performed a fine-mapping analysis by genotyping 134 SNPs using a custom Illumina iSelect array or Sequenom MassArray iPlex, followed by imputation of 1094 SNPs in 22 301 PrCa cases and 22 320 controls in The PRACTICAL consortium. Multiple stepwise logistic regression analysis identified four signals in the promoter or intronic regions of TERT that independently associated with PrCa risk. Gene expression analysis of normal prostate tissue showed evidence that SNPs within one of these regions also associated with TERT expression, providing a potential mechanism for predisposition to disease

    Effect of colour vision status on insect prey capture efficiency of captive and wild tamarins (Saguinus spp.)

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    The colour vision polymorphism of most New World primates is a model system to study the function of colour vision. Theories for the evolution of primate trichromacy focus on the efficient detection and selection of ripe fruits and young leaves amongst mature leaves, when trichromats are likely to be better than dichromats. We provide data on whether colour vision status affects insect capture in primates. Trichromatic tamarins (Saguinus spp.) catch more prey than dichromats, but dichromats catch a greater proportion of camouflaged prey than trichromats. The prey caught does not differ in size between the two visual phenotypes. Thus two factors may contribute to the maintenance of genetic polymorphism of middle- to long-wavelength photopigments in Platyrrhines: the advantage in finding fruit and leaves, which supports the maintenance of the polymorphism through a heterozygote advantage, and the dichromats’ exploitation of different (e.g., camouflaged) food, which results in frequency-dependent selection on the different colour vision phenotypes

    Nanomaterials Versus Ambient Ultrafine Particles: An Opportunity to Exchange Toxicology Knowledge

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    BACKGROUND: A rich body of literature exists that has demonstrated adverse human health effects following exposure to ambient air particulate matter (PM), and there is strong support for an important role of ultrafine (nanosized) particles. At present, relatively few human health or epidemiology data exist for engineered nanomaterials (NMs) despite clear parallels in their physicochemical properties and biological actions in in vitro models. OBJECTIVES: NMs are available with a range of physicochemical characteristics, which allows a more systematic toxicological analysis. Therefore, the study of ultrafine particles (UFP, <100 nm in diameter) provides an opportunity to identify plausible health effects for NMs, and the study of NMs provides an opportunity to facilitate the understanding of the mechanism of toxicity of UFP. METHODS: A workshop of experts systematically analyzed the available information and identified 19 key lessons that can facilitate knowledge exchange between these discipline areas. DISCUSSION: Key lessons range from the availability of specific techniques and standard protocols for physicochemical characterization and toxicology assessment to understanding and defining dose and the molecular mechanisms of toxicity. This review identifies a number of key areas in which additional research prioritization would facilitate both research fields simultaneously. CONCLUSION: There is now an opportunity to apply knowledge from NM toxicology and use it to better inform PM health risk research and vice versa.info:eu-repo/semantics/publishedVersio
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