Functional genomics of a symbiotic community : shared traits in the olive fruit fly gut microbiota

The olive fruit fly Bactrocera oleae is a major pest of olives worldwide and houses a specialized gut microbiota dominated by the obligate symbiont “Candidatus Erwinia dacicola”. Ca. E. dacicola is thought to supplement dietary nitrogen to the host, with only indirect evidence for this hypothesis so far. Here, we sought to investigate the contribution of the symbiosis to insect fitness and explore the ecology of the insect gut. For this purpose, we examined the composition of bacterial communities associated with Cretan olive fruit fly populations, and inspected several genomes and one transcriptome assembly. We identified, and reconstructed the genome of, a novel component of the gut microbiota, Tatumella sp. TA1, which is stably associated with Mediterranean olive fruit fly populations. We also reconstructed a number of pathways related to nitrogen assimilation and interactions with the host. The results show that, despite variation in taxa composition of the gut microbial community, core functions related to the symbiosis are maintained. Functional redundancy between different microbial taxa was observed for genes involved in urea hydrolysis. The latter is encoded in the obligate symbiont genome by a conserved urease operon, likely acquired by horizontal gene transfer, based on phylogenetic evidence. A potential underlying mechanism is the action of mobile elements, especially abundant in the Ca. E. dacicola genome. This finding, along with the identification, in the studied genomes, of extracellular surface structure components that may mediate interactions within the gut community, suggest that ongoing and past genetic exchanges between microbes may have shaped the symbiosis

On the generation and propagation of Rossby waves in an ocean with a zonally shoaling mixed layer

This paper presents the theory for freely propagating and forced Rossby waves in a continuously stratified ocean where the bouyancy frequency, N, varies with longitude and depth. In this study zonal variations in N occur because the climatological mixed layer depth, h, varies with longitude.With the assumption that changes in h occur on a length scale which is large compared to a horizontal wavelength the free modes on a β-plane are examined. It is found that realistic mixed layer depth changes can cause amplitude modulations, the largest amplitudes occurring where the mixed layer is shallowest. The requirement that h variations occur slowly is removed by employing a numerical model to study the free modes in a continuously stratified meridional channel. A criterion, based on the ratio of a horizontal length scale associated with the wave packet and the internal Rossby radius, is derived for determining when a free mode may be affected by the zonal variations in the stratification. Using climatological mixed layer depth data at 35N in the Atlantic (taken from Lamb, 1984) the basin modes are numerically determined. The major response is now concentrated where the mixed layer is deepest. This apparent contradiction is explained. A general theory is presented for calculating the forced basin mode response in terms of the free modes. As an example, a wind stress curl is applied as a body force over the mixed layer for a finite duration. After the forcing is removed the percentage that each basin mode contributes to the total solution is calculated. It is found that the dominant response to wind stress curl forcing can be significantly affected by the presence of a variable depth mixed layer. The implication of this study for the interaction between baroclinic Rossby waves and mixed layer dynamics is discussed

Carbon Monoxide Poisoning Resistance and Structural Stability of Single Atom Alloys

Platinum group metals (PGMs) serve as highly active catalysts in a variety of heterogeneous chemical processes. Unfortunately, their high activity is accompanied by a high affinity for CO and thus, PGMs are susceptible to poisoning. Alloying PGMs with metals exhibiting lower affinity to CO could be an effective strategy toward preventing such poisoning. In this work, we use density functional theory to demonstrate this strategy, focusing on highly dilute alloys of PGMs (Pd, Pt, Rh, Ir and Ni) with poison resistant coinage metal hosts (Cu, Ag, Au), such that individual PGM atoms are dispersed at the atomic limit forming single atom alloys (SAAs). We show that compared to the pure metals, CO exhibits lower binding strength on the majority of SAAs studied, and we use kinetic Monte Carlo simulation to obtain relevant temperature programed desorption spectra, which are found to be in good agreement with experiments. Additionally, we consider the effects of CO adsorption on the structure of SAAs. We calculate segregation energies which are indicative of the stability of dopant atoms in the bulk compared to the surface layer, as well as aggregation energies to determine the stability of isolated surface dopant atoms compared to dimer and trimer configurations. Our calculations reveal that CO adsorption induces dopant atom segregation into the surface layer for all SAAs considered here, whereas aggregation and island formation may be promoted or inhibited depending on alloy constitution and CO coverage. This observation suggests the possibility of controlling ensemble effects in novel catalyst architectures through CO-induced aggregation and kinetic trapping

Quantifying moment redistribution in FRP-strengthened RC beams

Consideration of moment redistribution (MR) in the design of continuous reinforced concrete (RC) beams results in an efficient and economical design. Adding fibre-reinforced polymer (FRP) materials to reinforced structures to enhance flexural capacity leads to a reduction in ductility, such that design standards severely limit use of the MR in their design. This has forced engineers to use elastic analyses for strengthening design, which can lead to FRP wastage. To overcome this, complicated or empirical solutions have been applied to solve the problem of MR in strengthened concrete members, with limited success. This paper presents a novel theoretical strategy for quantifying and tracking MR in such members by employing basic structural mechanics without any need for estimating rotation capacity or ductility. Fully non-linear flexural behaviour of continuous strengthened members can be predicted and any geometry, loading arrangement and strengthening technique or configuration can be considered. The numerical model is validated against existing experimental data from the literature. Good agreement is shown between the experimental and numerical data, with the significance of this work being that, potentially, for the first time MR could credibly and confidently be incorporated into design guides for FRP strengthening of RC structures.The authors gratefully acknowledge funding provided by the Engineering and Physical Sciences Research Council (EPSRC EP/K019015/1) and the project partners (Concrete Repairs Ltd, Fyfe, Highways England, WSP/Parsons Brinckerhoff and Tony Gee and partners) for this research project

Educating Adolescents about Puberty: What are we Missing?

Adolescents undergo significant physical and cognitive changes during their pubertal development. These changes contribute to and impact their future development. Educating adolescents at an early age about their expected development decreases the possible anxiety associated with this period of life and also helps adolescents make better choices in regards to their sexuality. In order to assess the degree of education regarding pubertal development and sexuality, we conducted a survey of late adolescents (Median age 19 years) and parents of adolescents. A total of 409 adolescents (237 females, 172 males) and 124 parents completed the survey. 14.4% of teens (36.6% of males and 2% of females) reported that no one spoke to them prior or during puberty about pubertal development or sexuality issues. Teens receiving some form of puberty/sexuality education did so at a median age of 13 for girls and 15 for boys. More than one source of information was the most common (49%) followed by mother only (20%). 85% of parents reported talking to their teens about pubertal development and sexuality. There were several differences between areas reported covered by parents but not by teens, for example 72% of parents reported talking to their teens about gender differences in growth but only 31% of teens reported being spoken to about that. Areas that are very poorly covered are breast development in boys and sexual assault/date rape in girls at 5% and 26% respectively. In summary, it appears that we continue to do a relatively poor job in educating our kids about their development and sexuality and we do it late. Boys are even less likely than girls to be talked to about many areas of pubertal development and sexuality and when that is done, it is done at a later age

Survey of northeastern hop arthropod pests and their natural enemies

The commercial production of hops (Humulus lupulus L.) in the northeastern United States is on the rise due to demand from local breweries. Several arthropod pests are economically damaging to hop yield and quality. Due to climate and landscape differences between traditional and resurging hop-growing regions, there is a need for region-specific integrated pest management (IPM). We first review hop pest and natural enemy biology and management strategies. Then the phenology, abundance, and peak date of arthropod pests scouted in seven Vermont hop yards is reported. Documentation of natural enemy abundance is also reported. Our 3-yr survey indicated that hop aphid (Phorodon humuli (Schrank)) populations were highest in the continually cool, wet season. Potato leafhopper (Empoasca fabae (Harris)) was a pest with an unpredictable arrival date and of special concern for first-year hop plants. Twospotted spider mite (Tetranychus urticae Koch) was a pest of concern in hot, dry conditions and after some broad-spectrum pesticide applications aimed at leafhoppers. This survey was the first step toward developing appropriate IPM tactics for modern day northeastern hop production. Further research should be focused on adjusting arthropod pest thresholds, disease management, and developing alternative control options for both arthropod and disease management

Solar Panel Integration as an Alternate Power Source on Centaur 2 (SPIAPS)

The dream of exploration has inspired thousands throughout time. Space exploration, in particular, has taken the past century by storm and caused a great advance in technology. In this project, a retractable solar panel array will be developed for use on the Centaur 2 Rover. Energy generated by the solar panels will go to power the Centaur 2 Robot (C2) or Regolith & Environment Science & Oxygen & Lunar Volatile Extraction (RESOLVE) payload, an in-situ resource utilization project. Such payload is designed to drill into lunar and Martian terrain as well as be able to conduct other geological testing; RESOLVE is slated for testing in 2012. Ultimately, this project will fit into NASA s larger goal of deep space exploration as well as long term presence outside Earth s orbit

Serviceability of non-prismatic concrete beams: Combined-interaction method

Interest in the shape optimisation of concrete members is increasing alongside the availability of fabric formwork as a relatively simple technique to cast non-prismatic concrete structures. Research has shown that up 40% of concrete can be saved when shape optimised concrete beams are cast in fabric forms. However, optimisation results in members with non-uniform cross-sections and the resulting beam is less stiff than an equivalent strength prismatic beam. Serviceability, rather than strength, may govern the design of such members and therefore understanding the serviceability behaviour (deflection and cracking) of shape optimised concrete members becomes is a critical design consideration. There are many methods which can be used to evaluate serviceability behaviour of reinforced concrete beams, including the full-interaction method, which assumes no slip between the reinforcement and the surrounding concrete, and the partial-interaction method which accounts for slip. The full-interaction method is based on a smeared crack approach and so is unsuited for the prediction of cracking behaviour. The partial-interaction method, on the other hand, assumes that cracks form through bond-stress transfer only. In the case of non-prismatic concrete beams, the cracking capacity varies along the member. Therefore, cracking can occur over extended regions (full and partial bond interaction regions) and so it can be argued that neither of these models is fully suitable for the prediction of deflections and cracking of shape-optimised concrete beams. In this paper, a novel combined-interaction method is, for the first time, presented to predict the serviceability behaviour of non-prismatic concrete beams by simulating both full and partial bond interactions at different cracked and uncracked regions along the length of the member. In order to validate this approach, two non-prismatic simply supported beams were cast and tested. The test results for deflections, crack widths and crack spacings were in good agreement with the predicted results