Rapid behavioral transitions produce chaotic mixing by a planktonic microswimmer

Despite their vast morphological diversity, many invertebrates have similar larval forms characterized by ciliary bands, innervated arrays of beating cilia that facilitate swimming and feeding. Hydrodynamics suggests that these bands should tightly constrain the behavioral strategies available to the larvae; however, their apparent ubiquity suggests that these bands also confer substantial adaptive advantages. Here, we use hydrodynamic techniques to investigate "blinking," an unusual behavioral phenomenon observed in many invertebrate larvae in which ciliary bands across the body rapidly change beating direction and produce transient rearrangement of the local flow field. Using a general theoretical model combined with quantitative experiments on starfish larvae, we find that the natural rhythm of larval blinking is hydrodynamically optimal for inducing strong mixing of the local fluid environment due to transient streamline crossing, thereby maximizing the larvae's overall feeding rate. Our results are consistent with previous hypotheses that filter feeding organisms may use chaotic mixing dynamics to overcome circulation constraints in viscous environments, and it suggests physical underpinnings for complex neurally-driven behaviors in early-divergent animals.Comment: 20 pages, 4 figure

Comparison of DC and SRF Photoemission Guns For High Brightness High Average Current Beam Production

A comparison of the two most prominent electron sources of high average current high brightness electron beams, DC and superconducting RF photoemission guns, is carried out using a large-scale multivariate genetic optimizer interfaced with space charge simulation codes. The gun geometry for each case is varied concurrently with laser pulse shape and parameters of the downstream beamline elements of the photoinjector to obtain minimum emittance as a function of bunch charge. Realistic constraints are imposed on maximum field values for the two gun types. The SRF and DC gun emittances and beam envelopes are compared for various values of photocathode thermal emittance. The performance of the two systems is found to be largely comparable provided low intrinsic emittance photocathodes can be employed

Impact of agribusiness labour on the child education in Cameroon

This paper aimed to assess the involvement of child labour in agribusinesses as well as the schooling pattern of children involved in these agribusinesses in Cameroon. For this study, some descriptive statistics and cross tabulations were computed using SPSS.20 and stata 13 software packages. The population of this study was made up of 51,190 individuals of both sexes that were concerned by the third Cameroon National Household Survey. The sample drawn from this population was constituted of individuals of age 5-17 years old, making a total of 17,550 children. The main results of this study revealed that agribusiness child labour was present everywhere in Cameroon and by both boys and girls. Children of all ages of the sample were concerned by the phenomenon and their level of education was essentially the primary. The impact of agribusiness child labour on education was positive because it helped the working and schooling children to provide means to finance their education and other needs. On the other hand, it has a negative impact on education because some children went for these jobs and finally stayed there and did not return back to school.Int. J. Agril. Res. Innov. & Tech. 5 (2): 58-63, December, 201

The valuation tool user guide: monetizing Cradle to Cradle®

This User Guide outlines the object, scope and expected deliverables from the Valuation Tool component of the Cradle to Cradle ® C2C BIZZ project. It describes the compendium of subtools that have been developed comprising: i) overview of funding tools; ii) C2C investment appraisal tool; and iii) C2C value indexing tool. The underpinning methodologies, as well as their inherent strengths and limitations are also described. The C2C BIZZ project as a whole aims specifically to promote and enhance the implementation of C2C methods in business site development within North Western Europe (NWE) (PAD, p.14). It is intended to infuse C2C notions into conventional site development, restructuring and management. The primary focus of the project is on planning, building and managing of business sites with C2C credentials (PAD, p.18) using sites in Lille Metropole (La Lainiere), London (London Sustainable Industries Park) and Luxemburg (Ecoparc Windhof) as experimental fields. C2C BIZZ is not concerned with the internal operations and activities of occupiers or users of the developed site. Accordingly, the scope of the valuation tool is confined to the planning, building and management of C2C sites. The deliverable from this component is a compendium of subtools (see Figure 1 below) that may be used to analyse the financial performance of C2C credentials in business sites to aid the making of a business case for such developments and evaluating the financial incentives for particular C2C site development projects. This entire work is premised on the argument that the wider adoption of C2C principles within the built environment depends on the rate of uptake by the private sector. The private sector, being profit driven, are likely to engage in C2C site development if they are convinced of its capacity to contribute to their business goals which ultimately is a return on their investment. The tool development described in this document attempts to provide a framework for collating an evidence base that can assist in articulating the business case for C2C in business site developments

Functional consequences of trust in the construction supply chain: a multi-dimensional view

Trust is often linked to the emergence of cooperative behaviours that contribute to successful project outcomes. However, some have questioned the functional relevance of trust in contractual relations, arguing that control-induced cooperation can emerge from enforcement of contracts. These mixed views are further complicated by the multi-dimensional nature of trust, as different trust dimensions could have varying functional consequences. The aim of this study was to provide some clarity on the functional consequence of trust in the project supply chain. Data was gathered through passive observations, document reviews and semi-structured interviews with supply chain parties on two case study projects in the UK. A thematic data analysis approach was used to uncover multiple perspectives on the functional consequences of trust in the supply chain. Findings revealed that the weaker dimensions of trust, which are impersonal (cognition-based and systems-based) and the stronger (relational-based) dimension of trust, all fostered beneficial behaviours in the supply chain (effective knowledge sharing and self-organising behaviours). However, additional behavioural consequences (relational flexibility and extra commitment) emerged when trust was relational in nature, implying that different trust dimensions and their associated behavioural consequences can be prioritized in the supply chain based on perceived work package risks

Degradation of Para-Phenylenediamine in Aqueous Solution by Photo-Fenton Oxidation Processes

In this research Photo-Fenton Oxidation of Para-Phenylenediamine (PPD) in aqueous solution by UV/Fenton’s reagent (Fe2+ and H2O2) was investigated. Experiments were conducted in a batch reactor, at pH 3.5 and at 25°C with a source of UV-C light. The effects of different reaction parameters such as initial PPD concentration, pH of the solution, ferrous concentration, Hydrogen peroxide concentration, on the oxidative degradation of PPD were measured. Final concentration of PPD and COD of the solution after treatment were determined to know degree of degradation of the compound. Iron source used for photo-Fenton’s oxidation were Ferrous Sulphate (FeSO4.7H2O).The optimum conditions established by Fenton’s oxidation without UV, were considered for this investigation. Only the maximum removal conditions were tried with the UV for reaction time of 3 hours. The results showed that under optimum experimental conditions, the pH 3.5, 50 mg/L H2O2, 3 mg/L Fe2+and UV reaction time of 3 hours, the initial concentration 10 mg/L of PPD was reduced by 71.20% with 65.89% COD removal. Likewise the removal efficiencies for PPD concentration of 20, 30, 40 and 50 mg/L keeping the same proportion of H2O2and Fe2+dosage (with ratios of PPD:Fe2+:H2O2::10:1:16.7) were investigated and the results showed, PPD removal were 65.10, 61.23, 58.34 and 54.26% and COD removal was 61, 54, 52 and 50.32% respectively. From the results obtained it can be concluded that Fenton’s reagent favours the lower concentration of Phenylenediamines and UV-C assisted photo-Fenton showed that the photo-Fenton process was very effective than the normal Fenton process.Keywords: Para-Phenylenediamine; COD; UV-C light; Fenton’s reagent; Oxidatio