Estimation of the coefficient of lateral stress used in the calculation of loads on buried structures

© ASCE. The average vertical pressure on a buried structure can be calculated using the silo theory, which assumes the translation of a vertical prism of soil above the structure that is resisted by friction on the sides of the prism. One of the key assumptions made is the value of the coefficient of lateral stress, K. In this study, an assumption regarding the rotation of principal stresses in the yielding soil has been used to calculate the average coefficient of lateral stress acting at the side of a prism of yielding soil above the horizontal buried structure. The calculated value using the proposed method agrees well with experimental observation made in literature for the value of K, and is suggested for use in the estimation of loads on buried structures, where it is expected that the structure will yield relative to a stiff body of soil

Market returns to acquirers of substantial assets

Does poor post-acquisition performance characterise firms that make non-M&A acquisitions? We investigate the wealth effects of substantial asset acquisitions (i.e. acquisitions that cost over $10 million) on acquiring firms' shareholders. We find significant abnormal positive market reaction to asset acquisition announcements and, contrary to findings for firms undertaking M&As, the acquiring firms perform exceptionally well post-acquisition. Our findings are robust to the research method weaknesses common to many studies of long-term performance and we control for free-cash-flow as well. Our results contradict the hubris hypothesis of acquisitions and lend weight to the argument that the auction-style process that characterizes corporate takeover bids contributes to overpayment

The Demutualisation of the Australian Stock Exchange: Causes and Consequences

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Centrifuge modelling of the initiation of cracks in a clay liner subjected to differential settlement with and without overburden pressure

Compacted clay liners are used in the basal and capping layers of landfills to separate the waste material from the environment. These liners are subjected to differential settlement through degradation of the waste or compression of the subgrade. This differential settlement induces cracking in the liner, and reduces the effectiveness of the clay as an en vironmental protection barrier. P hysical model tests were conducted in the geotechnical centrifuge to study the influence of differential settlement on clay liners and observe the crack mechanism using a consolidated kaolin clay beam to model the clay liner . Differential settlement was imposed on the clay beam by means of a trapdoor. Cracking in the clay was monitored through digital analysis of images taken as the tests were conducted using particle image velocimetry. The test investigate d the orientation and types of cracks formed with varying void dimensions and with and without overburden pressure The unconfined clay over the small trapdoor was able to support itself across the void; a punching shear failure occurred in the case of a wider trapdoor or greater overburden pressure

Competition in the market for takeover advisers

We investigate factors that motivate bidders to engage advisers, we model adviser selection and we test whether value-adding advisers gain market share. Our sample includes 801 attempted takeovers over 1989-1998 in Australia. Our results indicate advisers are likely to be engaged if the takeover deal is large, hostile, and includes non-cash compensation. We find deal completion is not as closely correlated with adviser rankings as does Rau (2000) but we confirm his finding that adviser ranked high on market value of deals advised do not have a comparative advantage in adding value to firms. However, we document some (limited) evidence that value- adding advisers achieve an increase in subsequent deal flow. Our results are consistent with specialization among takeover advisers

Mapping of Alternative Oilseeds from the Brazilian Caatinga and Assessment of Catalytic Pathways toward Biofuels Production

Biofuels are increasingly important renewable resources in the world's energy matrix that have challenged the scientific community as well as small and large farmers to develop alternatives to fossil fuels in order to achieve the aims of energy transition. In particular, Brazil's proven competitiveness in agribusiness together with its rich biodiversity put the country in a key position in the biofuels market. The semiarid Caatinga of northeastern Brazil, an exclusive biome rich in many oilseed species suitable for potential energy purposes, is of particular interest in this field. Nowadays, soybeans are the main feedstock used for the production of biodiesel, but, due to the increasing demand for biofuels, the search for alternative sources of oil from tropical flora with high productivity is crucial. Under this premise, this systematic review focuses on mapping Caatinga's vegetable oil crops that could be used as alternative raw materials for biofuels' production in Brazil, in addition to traditional soybeans and sugarcane. To gain more detailed insight into these matrices, their main properties, including oil content, fatty acid profile and physicochemical properties, are discussed. Moreover, an overview is provided of processes to synthesize different types of biofuels, particularly biodiesel and aviation biokerosene, including the routes employing homogeneous, enzymatic and mainly heterogeneous catalysts. Finally, future prospects and challenges for renewable biofuels and the Caatinga biome are addressed

Identification and expression analysis of microRNAs and targets in the biofuel crop sugarcane

<p>Abstract</p> <p>Background</p> <p>MicroRNAs (miRNAs) are small regulatory RNAs, some of which are conserved in diverse plant genomes. Therefore, computational identification and further experimental validation of miRNAs from non-model organisms is both feasible and instrumental for addressing miRNA-based gene regulation and evolution. Sugarcane (<it>Saccharum spp</it>.) is an important biofuel crop with publicly available expressed sequence tag and genomic survey sequence databases, but little is known about miRNAs and their targets in this highly polyploid species.</p> <p>Results</p> <p>In this study, we have computationally identified 19 distinct sugarcane miRNA precursors, of which several are highly similar with their sorghum homologs at both nucleotide and secondary structure levels. The accumulation pattern of mature miRNAs varies in organs/tissues from the commercial sugarcane hybrid as well as in its corresponding founder species <it>S. officinarum </it>and <it>S. spontaneum</it>. Using sugarcane <it>MIR827 </it>as a query, we found a novel <it>MIR827 </it>precursor in the sorghum genome. Based on our computational tool, a total of 46 potential targets were identified for the 19 sugarcane miRNAs. Several targets for highly conserved miRNAs are transcription factors that play important roles in plant development. Conversely, target genes of lineage-specific miRNAs seem to play roles in diverse physiological processes, such as <it>SsCBP1</it>. <it>SsCBP1 </it>was experimentally confirmed to be a target for the monocot-specific miR528. Our findings support the notion that the regulation of <it>SsCBP1 </it>by miR528 is shared at least within graminaceous monocots, and this miRNA-based post-transcriptional regulation evolved exclusively within the monocots lineage after the divergence from eudicots.</p> <p>Conclusions</p> <p>Using publicly available nucleotide databases, 19 sugarcane miRNA precursors and one new sorghum miRNA precursor were identified and classified into 14 families. Comparative analyses between sugarcane and sorghum suggest that these two species retain homologous miRNAs and targets in their genomes. Such conservation may help to clarify specific aspects of miRNA regulation and evolution in the polyploid sugarcane. Finally, our dataset provides a framework for future studies on sugarcane RNAi-dependent regulatory mechanisms.</p

Exercise training reveals inflexibility of the diaphragm in an animal model of patients with obesity-driven heart failure with a preserved ejection fraction

Background: Respiratory muscle weakness contributes to exercise intolerance in patients with heart failure with a preserved ejection fraction (HFpEF)—a condition characterized by multiple comorbidities with few proven treatments. We aimed, therefore, to provide novel insight into the underlying diaphragmatic alterations that occur in HFpEF by using an obese cardiometabolic rat model and further assessed whether exercise training performed only after the development of overt HFpEF could reverse impairments. Methods and Results: Obese ZSF1 rats (n=12) were compared with their lean controls (n=8) at 20 weeks, with 3 additional groups of obese ZSF1 rats compared at 28 weeks following 8 weeks of either sedentary behavior (n=13), high‐intensity interval training (n=11), or moderate‐continuous training (n=11). Obese rats developed an obvious HFpEF phenotype at 20 and 28 weeks. In the diaphragm at 20 weeks, HFpEF induced a shift towards an oxidative phenotype and a fiber hypertrophy paralleled by a lower protein expression in MuRF1 and MuRF2, yet mitochondrial and contractile functional impairments were observed. At 28 weeks, neither the exercise training regimen of high‐intensity interval training or moderate‐continuous training reversed any of the diaphragm alterations induced by HFpEF. Conclusions: This study, using a well‐characterized rat model of HFpEF underpinned by multiple comorbidities and exercise intolerance (ie, one that closely resembles the patient phenotype), provides evidence that diaphragm alterations and dysfunction induced in overt HFpEF are not reversed following 8 weeks of aerobic exercise training. As such, whether alternative therapeutic interventions are required to treat respiratory muscle weakness in HFpEF warrants further investigation

Practical computational toolkits for dendrimers and dendrons structure design

Dendrimers and dendrons offer an excellent platform for developing novel drug delivery systems and medicines. The rational design and further development of these repetitively branched systems are restricted by difficulties in scalable synthesis and structural determination, which can be overcome by judicious use of molecular modelling and molecular simulations. A major difficulty to utilise in silico studies to design dendrimers lies in the laborious generation of their structures. Current modelling tools utilise automated assembly of simpler dendrimers or the inefficient manual assembly of monomer precursors to generate more complicated dendrimer structures. Herein we describe two novel graphical user interface (GUI) toolkits written in Python that provide an improved degree of automation for rapid assembly of dendrimers and generation of their 2D and 3D structures. Our first toolkit uses the RDkit library, SMILES nomenclature of monomers and SMARTS reaction nomenclature to generate SMILES and mol files of dendrimers without 3D coordinates. These files are used for simple graphical representations and storing their structures in databases. The second toolkit assembles complex topology dendrimers from monomers to construct 3D dendrimer structures to be used as starting points for simulation using existing and widely available software and force fields. Both tools were validated for ease-of-use to prototype dendrimer structure and the second toolkit was especially relevant for dendrimers of high complexity and size.Peer reviewe