Arbuscular Mycorrhizal Fungi and Plant Chemical Defence: Effects of Colonisation on Aboveground and Belowground Metabolomes

Arbuscular mycorrhizal fungal (AMF) colonisation of plant roots is one of the most ancient and widespread interactions in ecology, yet the systemic consequences for plant secondary chemistry remain unclear. We performed the first metabolomic investigation into the impact of AMF colonisation by Rhizophagus irregularis on the chemical defences, spanning above- and below-ground tissues, in its host-plant ragwort (Senecio jacobaea). We used a non-targeted metabolomics approach to profile, and where possible identify, compounds induced by AMF colonisation in both roots and shoots. Metabolomics analyses revealed that 33 compounds were significantly increased in the root tissue of AMF colonised plants, including seven blumenols, plant-derived compounds known to be associated with AMF colonisation. One of these was a novel structure conjugated with a malonyl-sugar and uronic acid moiety, hitherto an unreported combination. Such structural modifications of blumenols could be significant for their previously reported functional roles associated with the establishment and maintenance of AM colonisation. Pyrrolizidine alkaloids (PAs), key anti-herbivore defence compounds in ragwort, dominated the metabolomic profiles of root and shoot extracts. Analyses of the metabolomic profiles revealed an increase in four PAs in roots (but not shoots) of AMF colonised plants, with the potential to protect colonised plants from below-ground organisms.     

Merit of hybrid EDFA/Raman amplification in fixed‐grid all‐optical network exploiting multirate transponders

The constant need to improve network capacity and reduce power consumption in current fixed‐grid WDM networks motivates researchers to find alternative solutions other than replacing the deployed equipment. One of the possible solutions is the use of hybrid EDFA/Raman amplifier, which improves signal‐to‐noise‐ratio in a point‐to‐point link. This work aims at quantifying, by means of a detailed power model, the effect of these novel ideas on the power consumption of the network, which is key to build a future green Internet. In particular, we consider the use of a randomly generated topology of 20 nodes to study the effect of hybrid amplification, fiber type, fiber span length, and sensitivity to average link length and average traffic per node. Results show that hybrid amplification in moderate pumping regime minimizes total network power consumption for networks made up of all 3 fiber types in particular for nonzero dispersion‐shifted fiber.     

Limited benefit of joint estimation in multi‐agent iterative learning

This paper studies iterative learning control (ILC) in a multi‐agent framework, wherein a group of agents simultaneously and repeatedly perform the same task. Assuming similarity between the agents, we investigate whether exchanging information between the agents improves an individual's learning performance. That is, does an individual agent benefit from the experience of the other agents? We consider the multi‐agent iterative learning problem as a two‐step process of: first, estimating the repetitive disturbance of each agent; and second, correcting for it. We present a comparison of an agent's disturbance estimate in the case of (I) independent estimation, where each agent has access only to its own measurement, and (II) joint estimation, where information of all agents is globally accessible. When the agents are identical and noise comes from measurement only, joint estimation yields a noticeable improvement in performance. However, when process noise is encountered or when the agents have an individual disturbance component, the benefit of joint estimation is negligible. Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

Effect of Radio Frequency Heating on Nalidixic Acid-Adapted Shiga Toxin-Producing and Non-pathogenic <Emphasis Type="Italic">Escherichia coli</Emphasis> Strains in Buffer

This study aimed to evaluate the use of nalidixic acid-adapted strains of three major Shiga toxin-producing Escherichia coli (STEC) and non-pathogenic E. coli for the use of radio frequency (RF) heating using phosphate buffer saline (PBS). The effectiveness of RF was evaluated on cocktails of various STEC serotypes (O157:H7, O26:H11, O111) and non-pathogenic E. coli at different endpoint temperatures (55, 60, and 65 °C). All strains were successfully adapted to nalidixic acid (Nal). In general, the results indicated that Nal-adapted strains were not significantly different from Nal-sensitive strains evaluated either before treatment or at the endpoint temperatures. Nal-adapted strains were, therefore, confirmed to be effective as marker organisms in studies involving the use of RF in buffer. Results also showed that the thermal inactivation of strains was more effective as the treatment temperature increased, particularly at 65 °C, which showed a 6.0 log CFU/ml reduction. The results of the present study serve as a baseline to study RF as a potential intervention technology for non-intact beef products.     

Stress and counterproductive work behavior: Multiple relationships between demands, control, and soldier indiscipline over time.

Cognitive Resource Theory (CRT) suggests that under high levels of stress, employees are more prone to committing indiscipline. As few studies have examined this relationship over time, the authors conducted a six-wave longitudinal study examining the relationship of soldiers’ indiscipline with work demands and control. The study included archival data collected quarterly over 2 years from 1,701 soldiers representing 10 units in garrison (Germany and Italy), in training rotations (Grafenwoehr, Germany), and on peacekeeping deployments (Kosovo, Kuwait). No main effects were found for work overload, and the findings for the moderating effects of control were contradictory. Within each time point, as work overload increased, soldiers who felt less control committed more indiscipline, supporting CRT. Over time, however, as work overload increased, soldiers who perceived less control 6 months earlier committed less indiscipline. Additionally, the authors found reverse causal effects for control such that prior perceptions of a lack of control were associated with indiscipline and prior incidents of indiscipline with less control. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Projection in surrogate decisions about life-sustaining medical treatments.

To honor the wishes of an incapacitated patient, surrogate decision makers must predict the treatment decisions patients would make for themselves if able. Social psychological research, however, suggests that surrogates' own treatment preferences may influence their predictions of others' preferences. In 2 studies (1 involving 60 college student surrogates and a parent, the other involving 361 elderly outpatients and their chosen surrogate decision maker), surrogates predicted whether a close other would want life-sustaining treatment in hypothetical end-of-life scenarios and stated their own treatment preferences in the same scenarios. Surrogate predictions more closely resembled surrogates' own treatment wishes than they did the wishes of the individual they were trying to predict. Although the majority of prediction errors reflected inaccurate use of surrogates' own treatment preferences, projection was also found to result in accurate prediction more often than counterprojective predictions. The rationality and accuracy of projection in surrogate decision making is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mg-substituted hydroxyapatite nanopowders: Synthesis,thermal stability and sintering behaviour

This paper reports a systematic investigation on Mg-substituted hydroxyapatite (Ca_10?xMg_x(PO₄)₆(OH)₂) nanopowders produced by precipitation of Ca(NO₃)₂·4H₂O and Mg(NO₃)₂. The Mg content ranged between 0.6 and 2.4 wt%. Semicrystalline Mg-substituted hydroxyapatite powders made up of needle-like nanoparticles were obtained, the specific surface area ranged between 87 and 142 m²/g. Pure hydroxyapatite nanopowder decomposed around 1000 °C. Mg-substituted hydroxyapatites were thermally stable up to 660 °C (x = 1.0), 760 °C (x = 0.5) and 840 °C (x = 0.25) showing a distinct decreased thermal stability with respect to the pure sample.A relevant displacement of the sintering curve at lower temperature as a function of Mg content was observed, comparing to the behaviour of a pure HAp material, synthesized following the same procedure, and ascribed to the β-TCP formation.     

Microbial and toxic evaluation of raw and treated olive oil mill wastewaters

BACKGROUND: Olive oil mill wastewaters (OMW) from a three‐phase system were treated in a laboratory‐scale continuous stirred tank reactor (CSTR) for hydrogen production. Microbiological and physicochemical characterizations of raw and anaerobically treated olive oil mill effluents were performed. Toxicity assessment was also conducted in order to determine the impact of residual waters on the aquatic environment. RESULTS: Pseudomonas aeruginosa that has the ability to utilize phenolic compounds was isolated in raw OMW, along with several gram‐negative bacteria (Serratia odorifera, Enterobacter cloacae and Aeromonas hydrophila). The dominant species in the untreated effluent appears to be Enterobacter cloacae, whereas in the treated effluent it is Citrobacter braakii. Phenols, pH, NO^?₂, total dissolved solids (TDS) and conductivity were the main parameters related to the observed toxicity. CONCLUSION: A significant differentiation in the microbiological flora was detected between treated and untreated effluents whereas the microbial communities were correlated to the toxicity test results, pointing to the need for further research regarding identification of the microbial flora. This can improve the treatment processes to optimize management of OMW for environmentally safe discharge. Copyright © 2010 Society of Chemical Industry