Quantifying granivory in a reconstructed prairie: affects of season, species, seed predators, sacrificial food, and the chemical deterrent capsaicin

Floral diversity of reconstructed prairies is often low compared to remnant prairies. Studies have demonstrated it is feasible to increase forb diversity in these prairies through overseeding and mowing, but overall rates of seedling establishment range from 0.1% to 1% of sown pure live seed. One explanation may be the ubiquitous populations of granivorous animals eating much of the seed . In this thesis I measured the amount of granivory occurring in a reconstructed prairie. I also tested how season, seed species, seed predator, sacrificial food, and chemical deterrents affect granivory in the reconstructed prairie. I hypothesized that granivores remove significant amounts of seeds broadcast onto an established grassland, and vertebrate and smaller granivores would prefer different species of seeds. A third hypothesis was that granivores would influence seedling establishment and it would be possible to reduce granivory through the addition of a sacrificial food or a chemical feeding deterrent. To answer these questions I glued a known number of seeds to sandpaper cards, apply various treatments to the seeds or their surroundings, and count the remaining seeds over the following weeks. The first experiment to quantify levels of seed predation involved Silphium integrifolium. During the summer of 2006,seed cards were randomly placed in 16, 5 x 5-m plots. At the wholeplot level, the plots were treated with the addition of a sacrificial food (Helianthus annus). At the within-plot level, the seeds were treated with the chemical capsaicin. I assessed the rate of removal of these seeds over an 18 day period. During the fall of 2006, this experiment was repeated with modifications. The sacrificial food and capsaicin treatments were at the whole-plot level and one of three species (Silphium integrifolium, Dodecatheon meadia, and Phlox pilosa) were at the within-plot level. Seeds of these species were broadcast during the fall of 2006. During the spring of 2007, seedlings were counted the following spring and analyzed to detect if the amount of granivory the previous fall affected seedling establishment. Small wire mesh exclosures were built to test for the difference in granivory by vertebrate and invertebrate granivores. Seeds of Ratibida pinnata, Sorghastrum nutans, and Dale a purpurea were placed inside on seed cards and their rate of loss was recorded. Seed losses across trials ranged from 60% to over 98%. Significant factors included the time of year, predators involved, and species of seed. It was possible to reduce granivory in some cases. Capsaicin-treated D. meadia seeds yielded 2.1x as many seedlings as untreated seeds. Addition of sacrificial food also significantly (p=0.0006) reduced the amount of seed loss in Summer 2006 but not Fall 2006. There were significant (p From these results, I have concluded granivory is an important factor in plant establishment within reconstructed prairies. I also found it is possible to reduce granivory, possibly increasing the success of a seed addition

AES Final Report & Technical Proceedings

the overarching goal of the Arctic Energy Summit was to create a forum to engage in a dialogue on energy development in the Arctic. the Summit brought together the people of the Arctic to discuss, share and create a balanced approach toward sustainable extractive, renewable and rural power; with the vision of creating energy wealth while eliminating energy poverty. to assist in the achievement of this goal, Arctic energy was examined as comprising two energy sources, extractive and renewable; and two methods of deployment, external and internal. Extractive sources - oil, gas, coal, natural gas from coal seams, methane hydrates - all have an external component, in which the resource is used outside or external to its source, typically used for the creation of wealth; as well as having an internal deployment for use by the people of the north. likewise, renewable energy sources - wind, geothermal, hydro and biomass - all can be deployed within, as well as external to, the Arctic

ZERO NET ENERGY TEST HOUSE

This paper describes the first phase of a residential research program to reduce the impact of new construction on the environment through research and education using a Zero Net Energy Test House as a framework. Containing four bedrooms, three and a half baths, the 1,800 square foot house, 1,000 square foot basement, is located in Omaha, Nebraska. It is being used to validate several research projects and provides a platform for applications research of a number of technological advances. Laminated photovoltaic solar panels, a wind turbine, and an occupant monitoring energy control system are some of the sustainable design innovations incorporated. Sustainable features are described that detail the application for LEED Platinum certification. Integrated into several University of Nebraska courses, the house has reached more than 200 students in the past year. Interdisciplinary teaching has involved design, construction, research, monitoring and energy analysis. Education opportunities have reached K–12 students, industry professionals, and public through tours and presentations

The clinical presentation of preterm cerebellar haemorrhage

The objective of this study was to evaluate clinical symptoms and findings on cranial ultrasound (CUS) in preterm infants with cerebellar haemorrhage through retrospective analysis of all preterm infants with a postnatal CUS or MRI diagnosis of cerebellar haemorrhage admitted in a tertiary care centre between January 2002 and June 2009. Fifteen infants were identified; median gestational age was 25 2/7 weeks and median birth weight 730 g. We discerned six types of haemorrhage: subarachnoid (n=3), folial (n=1), lobar (n=9, of which 4 bilateral), giant lobar (n=1, including vermis) and contusional (n=1). Especially in infants with lobar cerebellar haemorrhage, CUS showed preceding or concurrent lateral ventricle dilatation, mostly without intraventricular haemorrhage (IVH). Thirteen infants suffered from notable, otherwise unexplained motor agitation in the days preceding the diagnosis. In conclusion, motor agitation may be a presenting symptom of cerebellar haemorrhage in preterm infants. Unexplained ventriculomegaly can be a first sign of cerebellar haemorrhage and should instigate sonographic exploration of the cerebellum

Computational Model Explains High Activity and Rapid Cycling of Rho GTPases within Protein Complexes

Formation of multiprotein complexes on cellular membranes is critically dependent on the cyclic activation of small GTPases. FRAP-based analyses demonstrate that within protein complexes, some small GTPases cycle nearly three orders of magnitude faster than they would spontaneously cycle in vitro. At the same time, experiments report concomitant excess of the activated, GTP-bound form of GTPases over their inactive form. Intuitively, high activity and rapid turnover are contradictory requirements. How the cells manage to maximize both remains poorly understood. Here, using GTPases of the Rab and Rho families as a prototype, we introduce a computational model of the GTPase cycle. We quantitatively investigate several plausible layouts of the cycling control module that consist of GEFs, GAPs, and GTPase effectors. We explain the existing experimental data and predict how the cycling of GTPases is controlled by the regulatory proteins in vivo. Our model explains distinct and separable roles that the activating GEFs and deactivating GAPs play in the GTPase cycling control. While the activity of GTPase is mainly defined by GEF, the turnover rate is a sole function of GAP. Maximization of the GTPase activity and turnover rate places conflicting requirements on the concentration of GAP. Therefore, to achieve a high activity and turnover rate at once, cells must carefully maintain concentrations of GEFs and GAPs within the optimal range. The values of these optimal concentrations indicate that efficient cycling can be achieved only within dense protein complexes typically assembled on the membrane surfaces. We show that the concentration requirement for GEF can be dramatically reduced by a GEF-activating GTPase effector that can also significantly boost the cycling efficiency. Interestingly, we find that the cycling regimes are only weakly dependent on the concentration of GTPase itself

Anti- Japanese-Encephalitis-Viral Effects of Kaempferol and Daidzin and Their RNA-Binding Characteristics

Background: New therapeutic tools and molecular targets are needed for treatment of Japanese encephalitis virus (JEV) infections. JEV requires an a-1 translational frameshift to synthesize the NS1 ’ protein required for viral neuroinvasiveness. Several flavonoids have been shown to possess antiviral activity in vitro against a wide spectrum of viruses. To date, the antiviral activities of flavonol kaempferol (Kae) and isoflavonoid daidzin (Dai) against JEV have not been described. Methodology/Principal Findings: The 50 % cytotoxic concentration (CC50) and 50 % effective concentration (EC50) against JEV were investigated in BHK21 cells by MTS reduction. Activity against viral genomic RNA and proteins was measured by real-time RT-PCR and western blotting. The frameshift site RNA-binding characterization was also determined by electrospray ionization mass spectrometry, isothermal titration calorimetry and autodocking analysis. EC 50 values of Kae and Dai were 12.6 and 25.9 mM against JEV in cells pretreated before infection, whereas in cells infected before treatment, EC50 was 21.5 and 40.4 mM, respectively. Kae exhibited more potent activity against JEV and RNA binding in cells following internalization through direct inhibition of viral replication and protein expression, indicating that its antiviral activity was principally due to direct virucidal effects. The JEV frameshift site RNA (fsRNA) was selected as a target for assaying Kae and Dai. ITC of fsRNA revealed an apparent Kb value for Kae that was nine fold stronger than that for Dai. This binding was confirmed and localized to the RNA using ESI-MS and autodock analysis. Kae could form non-covalent complexes wit

Membrane Recruitment of Scaffold Proteins Drives Specific Signaling

Cells must give the right response to each stimulus they receive. Scaffolding, a signaling process mediated by scaffold proteins, participates in the decoding of the cues by specifically directing signal transduction. The aim of this paper is to describe the molecular mechanisms of scaffolding, i.e. the principles by which scaffold proteins drive a specific response of the cell. Since similar scaffold proteins are found in many species, they evolved according to the purpose of each organism. This means they require adaptability. In the usual description of the mechanisms of scaffolding, scaffold proteins are considered as reactors where molecules involved in a cascade of reactions are simultaneously bound with the right orientation to meet and interact. This description is not realistic: (i) it is not verified by experiments and (ii) timing and orientation constraints make it complex which seems to contradict the required adaptability. A scaffold protein, Ste5, is used in the MAPK pathway of Saccharomyces Cerevisiae for the cell to provide a specific response to stimuli. The massive amount of data available for this pathway makes it ideal to investigate the actual mechanisms of scaffolding. Here, a complete treatment of the chemical reactions allows the computation of the distributions of all the proteins involved in the MAPK pathway when the cell receives various cues. These distributions are compared to several experimental results. It turns out that the molecular mechanisms of scaffolding are much simpler and more adaptable than previously thought in the reactor model. Scaffold proteins bind only one molecule at a time. Then, their membrane recruitment automatically drives specific, amplified and localized signal transductions. The mechanisms presented here, which explain how the membrane recruitment of a protein can produce a drastic change in the activity of cells, are generic and may be commonly used in many biological processes

Energy for cities: Supply, demand and infrastructure investment

© 2017, Springer International Publishing AG. Energy is essential to all activities in all regions of a country. However the density of energy use in, and our economic dependence on, cities means that it is more critical for urban areas. Nevertheless we suggest that the provision of energy for urban areas cannot be considered separately from the national context. We will demonstrate how to assess the ability of a nation to invest in energy infrastructure for the benefit of cities. Our approach exploits data sets which are available in most industrialised countries, and we select two quite different case studies to illustrate our method: the Colombia (Bogota) and UK (London). Our focus for energy sustainability in cities is quality of life and reduced fossil-fuel emissions. We will show that the main target for cities should be to improve air quality and reduce energy demand by improving energy efficiency