Briefing: Factored material properties and limit state loads-unlikely extreme or impossible pretense

In the limit state design (LSD) method each design criterion is formally stated and assessed using a performance function. The performance function defines the relationship between the design parameters and the design criterion. In practice, LSD involves factoring up loads and factoring down calculated strengths and material parameters. This provides a convenient way to carry out routine probabilistic-based design. The factors are statistically calculated to produce a design with an acceptably low probability of failure. Hence the ultimate load and the design material properties are mathematical concepts that have no physical interpretation. They may be physically impossible. Similarly, the appropriate analysis model is also defined by the performance function and may not describe the real behaviour at the perceived physical equivalent limit condition. These points must be understood to avoid confusion in the discussion and application of partial factor LSD methods

Report of the NAFO Joint Commission-Scientific Council Working Group on Ecosystem Approach Framework to Fisheries Management (WG-EAFFM) Meeting

1. Opening by the co-Chairs, Robert Day (Canada) and Andrew Kenny (EU) 2. Appointment of Rapporteur 3. Adoption of Agenda 4. SC response to FC requests for advice: a. Consideration of 2014 SC advice regarding extent of the New England and Corner Rise Seamounts (Annex 13 of FC Doc. 16-20) b. Risk assessment of scientific surveys impact on VME in closed areas (2016 FC Request to SC #3) 5. Discussion of ongoing matters: a. Assessment of NAFO bottom fisheries SAI (2016 FC Request to SC # 6) b. Progress of analysis undertaken by EU NEREIDA funded research project c. Update on identification and mapping of sensitive species and habitats in the NAFO area d. Further development and application of the Ecosystems Approach to Fisheries (EAF) Roadmap, including further consideration of any issues raised at the Scientific Council Meeting, 01-15 June 2017 e. Alfonsino fishery on seamounts in the NAFO Regulatory Area. 6. Recommendations to forward to the Commission and Scientific Council 7. Other Matters a. Presentation: Canada’s Marine Conservation targets for 2017 and 2020: The Role of Fisheries b. NAFO Working Group on Improving Efficiency of NAFO Working Group Process c. Recommendation for a new co-Chair d. Timely availability of meeting reports 8. Adoption of Report 9. Adjournmen

Synthesis, Structure, and Activity of Enhanced Initiators for Olefin Metathesis

A series of ruthenium olefin metathesis catalysts of the general structure (H_2IMes)(PR_3)(Cl)_2Ru CHPh (H_2IMes = 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene) have been prepared; these complexes are readily accessible in two steps from commercially available (H_2IMes)(PCy_3)(Cl)_2Ru CHPh. Their phosphine dissociation rate constants (k_1), relative rates of phosphine reassociation, and relative reaction rates in ring-opening metathesis polymerization (ROMP) and ring-closing metathesis (RCM) have been investigated. The rates of phosphine dissociation (initiation) from these complexes increase with decreasing phosphine donor strength. Complexes containing a triarylphosphine exhibit dramatically improved initiation relative to (H_2IMes)(PCy_3)(Cl)_2Ru CHPh. Conversely, phosphine reassociation shows no direct correlation with phosphine electronics. In general, increased phosphine dissociation leads to faster olefin metathesis reaction rates, which is of direct significance to both organic and polymer metathesis processes

Global Communication and Cross-Cultural Competence: Twenty-First Century Micro-Case Studies

Sensitivity to diversity now demands a strategic understanding of the importance of cross-cultural communication competence in every action in organizations, communities, and nations throughout the world. This article contains seven micro-cases, each of which highlights a discussion of communication and cultural impact. The cases range from issues related to handshakes, communication with powerful people, collaborating in a divergent culture, unintended impact in meetings, and regional pronunciation differences. The cases include discussion questions, references for additional reading, and one unique feature: a “bumper sticker” summary. The article features a section on Approaching the Challenges. This discusses major communication and cultural theories, which provides a basis for avoiding or reconciling differences. The concluding section, Extending Indirect Experiential Opportunities, advocates specific methods to evolve an individual’s global mind-set and communication capabilities

Neutral Nickel(II)-Based Catalysts for Ethylene Polymerization

Neutral salicylaldiminato Ni(II) complexes have been synthesized, and their structure has been confirmed by an X-ray analysis of complex 4e. These compounds are active catalysts for the polymerization of ethylene under mild conditions in the presence of a phosphine scavenger such as Ni(COD)_2 or B(C_6F_5)_3

Polyelectrolyte-Linked Film Assemblies of Nanoparticles and Nanoshells: Growth, Stability, and Optical Properties

Multi-layer films of nanoparticles and nanoshells featuring various polymeric linkage molecules have been assembled and their optical properties characterized. The growth dynamics, including molecular weight effects, and stability of the various nanoparticle film constructions, using both single polymer as well as combinations of alternating charge polyelectrolytes as linking mechanisms, are presented. The polymeric linkers studied include poly-L-lysine, poly-L-arginine, poly(allylamine hydrochloride), and polyamidoamine dendrimers. Significantly air stable films were achieved with the use of multi-layered polymeric bridges between the nanoparticles and nanoshells. Optical sensitivity normally observed with these nanomaterials in solution was observed for their corresponding film geometries, with the nanoshell films exhibiting a markedly higher ability to report their local dielectric environment

The Perfect Spill: Solutions for Averting the Next Deepwater Horizon

In this article the authors comment on the oil spill incident from the Deepwater Horizon, particularly on its economic and ecological damages. The authors highlighted the disaster as an event wherein much is needed to be learned so that future oil spills can be avoided. One lesson refers to the valuability of natural capital assets and other public entities that are at risks due to private interests and that better regulations and incentives are needed to protect these assets against risks

Differentiation of Zebrafish Melanophores Depends on Transcription Factors AP2 Alpha and AP2 Epsilon

A model of the gene-regulatory-network (GRN), governing growth, survival, and differentiation of melanocytes, has emerged from studies of mouse coat color mutants and melanoma cell lines. In this model, Transcription Factor Activator Protein 2 alpha (TFAP2A) contributes to melanocyte development by activating expression of the gene encoding the receptor tyrosine kinase Kit. Next, ligand-bound Kit stimulates a pathway activating transcription factor Microphthalmia (Mitf), which promotes differentiation and survival of melanocytes by activating expression of Tyrosinase family members, Bcl2, and other genes. The model predicts that in both Tfap2a and Kit null mutants there will be a phenotype of reduced melanocytes and that, because Tfap2a acts upstream of Kit, this phenotype will be more severe, or at least as severe as, in Tfap2a null mutants in comparison to Kit null mutants. Unexpectedly, this is not the case in zebrafish or mouse. Because many Tfap2 family members have identical DNA–binding specificity, we reasoned that another Tfap2 family member may work redundantly with Tfap2a in promoting Kit expression. We report that tfap2e is expressed in melanoblasts and melanophores in zebrafish embryos and that its orthologue, TFAP2E, is expressed in human melanocytes. We provide evidence that Tfap2e functions redundantly with Tfap2a to maintain kita expression in zebrafish embryonic melanophores. Further, we show that, in contrast to in kita mutants where embryonic melanophores appear to differentiate normally, in tfap2a/e doubly-deficient embryonic melanophores are small and under-melanized, although they retain expression of mitfa. Interestingly, forcing expression of mitfa in tfap2a/e doubly-deficient embryos partially restores melanophore differentiation. These findings reveal that Tfap2 activity, mediated redundantly by Tfap2a and Tfap2e, promotes melanophore differentiation in parallel with Mitf by an effector other than Kit. This work illustrates how analysis of single-gene mutants may fail to identify steps in a GRN that are affected by the redundant activity of related proteins

Differences in estimates of size distribution of beryllium powder materials using phase contrast microscopy, scanning electron microscopy, and liquid suspension counter techniques

Accurate characterization of the physicochemical properties of aerosols generated for inhalation toxicology studies is essential for obtaining meaningful results. Great emphasis must also be placed on characterizing particle properties of materials as administered in inhalation studies. Thus, research is needed to identify a suite of techniques capable of characterizing the multiple particle properties (i.e., size, mass, surface area, number) of a material that may influence toxicity. The purpose of this study was to characterize the morphology and investigate the size distribution of a model toxicant, beryllium. Beryllium metal, oxides, and alloy particles were aerodynamically size-separated using an aerosol cyclone, imaged dry using scanning electron microscopy (SEM), then characterized using phase contrast microscopy (PCM), a liquid suspension particle counter (LPC), and computer-controlled SEM (CCSEM). Beryllium metal powder was compact with smaller sub-micrometer size particles attached to the surface of larger particles, whereas the beryllium oxides and alloy particles were clusters of primary particles. As expected, the geometric mean (GM) diameter of metal powder determined using PCM decreased with aerodynamic size, but when suspended in liquid for LPC or CCSEM analysis, the GM diameter decreased by a factor of two (p < 0.001). This observation suggested that the smaller submicrometer size particles attached to the surface of larger particles and/or particle agglomerates detach in liquid, thereby shifting the particle size distribution downward. The GM diameters of the oxide materials were similar regardless of sizing technique, but observed differences were generally significant (p < 0.001). For oxides, aerodynamic cluster size will dictate deposition in the lung, but primary particle size may influence biological activity. The GM diameter of alloy particles determined using PCM became smaller with decreasing aerodynamic size fraction; however, when suspended in liquid for CCSEM and LPC analyses, GM particle size decreased by a factor of two (p < 0.001) suggesting that alloy particles detach in liquid. Detachment of particles in liquid could have significance for the expected versus actual size (and number) distribution of aerosol delivered to an exposure subject. Thus, a suite of complimentary analytical techniques may be necessary for estimating size distribution. Consideration should be given to thoroughly understanding the influence of any liquid vehicle which may alter the expected aerosol size distribution