Initial success of native grasses is contingent on multiple interactions among exotic grass competition, temporal priority, rainfall and site effects.

Ecological communities are increasingly being recognized as the products of contemporary drivers and historical legacies that are both biotic and abiotic. In an attempt to unravel multiple layers of ecological contingency, we manipulated (i) competition with exotic annual grasses, (ii) the timing of this competition (temporal priority in arrival/seeding times) and (iii) watering (simulated rainfall) in a restoration-style planting of native perennial grasses. In addition, we replicated this experiment simultaneously at three sites in north-central California. Native perennial grasses had 73-99 % less cover when planted with exotic annuals than when planted alone, but this reduction was greatly ameliorated by planting the natives 2 weeks prior to the exotics. In a drought year, irrigation significantly reduced benefits of early planting so that these benefits resembled those observed in a non-drought year. There were significant differences across the three sites (site effects and interactions) in (i) overall native cover, (ii) the response of natives to competition, (iii) the strength of the temporal priority effect and (iv) the degree to which supplemental watering reduced priority effects. These results reveal the strong multi-layered contingency that underlies even relatively simple communities

Aboveground Net Primary Productivity in Grazed and Ungrazed pastures: Grazing Optimisation Hypothesis or Local Extinction of Vegetation Species

The controversy that has surrounded herbivory studies in the last few decades prompted our investigation to establish the extent to which herbivore optimisation hypothesis or compensatory growth evidence is real. We used the traditional movable cage method to collect primary productivity data on herbage, functional groups and key individual grass species in various controlled large herbivore treatments in an east African savanna. The herbivore treatments in triplicate blocks included cattle, wild herbivores with and without mega herbivores and combinations of cattle and wild herbivores also with and without mega herbivores. The findings revealed that at herbage level, most grazed treatments (four out of five) had higher productivity than the ungrazed control and three showed grazing optimisation curve at sixth polynomial degree between monthly productivity and grazing intensity (1-g/ng). At functional group level forbs productivity was higher in the ungrazed control than in any of the grazed treatments while at individual grass species level _Themeda triandra_ productivity was higher in all grazed treatments than in ungrazed control. We conclude against presence of herbivore optimisation hypothesis at herbage, functional group and species level because of lack of attributable grazing effect in grazed treatments that matches complex ecological effects in the ungrazed treatment

Monoamine oxidase (MAO) inhibitory effects of candidate MAO inhibitors found in cigarette smoke.

There is strong evidence that tobacco smoke inhibits both MAO A and MAO B isoforms in the body. However, which components of cigarette smoke are responsible for MAO inhibition is not clear yet. Our group has identified six previously unidentified candidate MAO inhibitors from the tobacco smoke. The MAO inhibitory effects of these candidate inhibitors were compared with that of nicotine and TPM (Tobacco Particulate Matter). An SH-SY5Y cell line was exposed to different regimens of ethanol (control), nicotine, TPM and the cocktail of candidate inhibitors. A final concentration 0.2 μM nicotine was used and the concentration of each candidate inhibitor was relative to that originally found in TPM. We found that nicotine did not have any significant MAO inhibitory effect compared to the control. TPM inhibited overall MAO activity by 39%, while the MAO inhibition by cocktail of candidate inhibitors was 47%. The results suggest that the candidate inhibitors identified by our group are the major contributors to the total MAO inhibitory activity depicted by cigarette smoke and potentially unlocks the mystery behind the components responsible for MAO inhibition by cigarette smoke in smokers

Pressure, Temperature and Dwell Time Effects on Fatigue Life in 304 Stainless Steel Using a R5-based Mechanistic Fatigue Model

AbstractThis paper aims to evaluate the effects of pressure, temperature, pipe wall thickness and dwell time on fatigue life in 304 stainless steel. For a given dwell time and temperature-internal pressure combination, fatigue life is calculated using the mechanistic fatigue model (MFM) presented. In addition, the influence of pipe wall thickness is also examined. The MFM uses Tresca strain range for initiation and Rankine strain range to account for crack growth rate up to a crack limiting length. The results showed that fatigue life was generally lower for a given load combination in the thinner pipe considered given its smaller surface area compared to the thicker pipe. This led to higher plastic strains and consequently, faster crack growth rates. Also, dwell time influences fatigue life with longer dwell times found to be more damaging. However, the influence of dwell time is tightly coupled with pipe wall thickness as it determines the nature of the thermal gradients developed

The educational experiences of autistic children with and without extreme demand avoidance behaviours

Extreme demand avoidance (EDA) is increasingly described as part of the autism spectrum and is sometimes diagnosed as Pathological Demand Avoidance (PDA). Yet little is known, about the educational experiences of children with and without EDA behaviours. Using an online survey collecting both quantitative and qualitative data, 211 parents reported on the school experiences of their autistic children. 57 parents had a child with an additional diagnosis of PDA (AUT-PDA); 91 had a child with no diagnosis of PDA but, according to parent report, displayed EDA behaviours (AUT-EDA); and 63 had a child with neither a PDA diagnosis nor EDA behaviours (AUT). Results demonstrated that there were few group differences in terms of the frequency of failed school placements and exclusions. However, children in the AUT-EDA/-PDA groups had higher levels of behaviour that challenges, which were particularly high in those with a PDA diagnosis. There were no significant differences in school exclusions, but the fact that these occurred across all groups is of concern. Qualitative results suggested overwhelmingly negative school experiences for all groups but especially the AUT-EDA and AUT-PDA groups. Parents attributed such experiences to misunderstanding of their children’s diagnoses and a lack of targeted support

Vectors for N- or C-terminal positioning of the yeast Gal4p DNA binding or activator domains

EMTREE drug terms: fungal protein; heat shock protein 90; hybrid protein; transcription factor EMTREE medical terms: amino terminal sequence; article; carboxy terminal sequence; DNA binding; DNA binding domain; expression vector; Gal4p domain; gene activation; gene activation domain; gene expression; nonhuman; plasmid; plasmid ADC; plasmid BDC; protein domain; protein protein interaction; technique; two hybrid system; yeast MeSH: Binding Sites; DNA-Binding Proteins; Genetic Vectors; Protein Structure, Tertiary; Recombinant Fusion Proteins; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Trans-Activation (Genetics); Transcription Factors; Two-Hybrid System Techniqu

Effect of Plasticity of Soil on Seismic Response of Pile Foundation: Parametric Study

Much of the reported research on the dynamic analysis of pile foundations assumes linear behavior of soil that may not be valid at strong excitations. In this paper material nonlinearity of soil caused by plasticity and work hardening is considered for the dynamic analysis of pile foundations. An advanced plasticity based soil model, HISS, is incorporated in a finite element technique. Analysis is carried out in the time domain. The algorithm is verified with available analytical results and then linear and nonlinear responses of a single end bearing pile are compared. Effects of different frequencies of excitation (harmonic) and ratio of rigidity of soil and pile have been investigated

Cassava utilization and potential markets

Report on potential markets for cassava and case studies of its role in the economies of Brazil, Thailand, and India - discusses supply and demand prospects and projections for cassava in food, industrial starch, and feed markets; place of cassava in the economies of three developing countries, including such aspects as agricultural production, food utilization, and export of cassava: makes recommendations with regard to agricultural research priorities. Bibliography, statistical data

Development of a Loading History for Seismic Testing of Architectural Glass in a Shop-Front Wall System

Moderate earthquakes can pose significant threats to the serviceability and structural integrity of the architectural glazing systems that are included in most building envelope systems. Building envelope damage can cause considerable economic losses due to operational disruptions for extended periods following an earthquake. Furthermore, glazing system structural failures are potentially hazardous to both building occupants and pedestrians. In this paper a systematic analytical study of the effect of the SOOE component of the 1940 El Centro earthquake on the response of a one-storey glass and aluminum shop-front wall system is presented. The seismic response of a one-storey commercial building comprised of three reinforced masonry walls, a glass and aluminum shop-front wall system, and a steel bar joist metal deck roof system was determined using the ABAQUS and SAP 90 finite element packages. In this study, the roof was considered incapable of transferring lateral forces to the walls and therefore its stiffness was ignored. Significant differences in the natural frequencies obtained from the two models were observed. These differences can be traced to different elements, different number of elements, different number of concentrated mass and nonstructural mass distribution, and variations in the number of supports used in the two models. For the El Centro ground motions perpendicular to the plane of the shop-front wall, displacements and drifts calculated by the ABAQUS and SAP 90 models differed considerably. This variation was probably due to modelling differences in the front steel frame. For El Centro ground motions parallel to the plane of the shop-front wall, displacements and drifts calculated by the ABAQUS and SAP 90 models were in much better agreement. It should be noted that for testing architectural glass the inplane drifts are more important. Typical values of inplane displacement reached 2.0% of the overall building height of 6.10 m, while the drifts reached 2.8% of the 1.83 m glazing opening. Copyright © 1996 Elsevier Science Ltd