A urine patch framework to simulate nitrogen leaching on New Zealand dairy farms

On New Zealand dairy farms, it is the nitrogen excreted directly onto pasture, particularly urine, that drives nitrogen (N) leaching from the farm. A new framework (UPF: Urine Patch Framework) is presented that post-processes the results of a whole farm model and runs a mechanistic soil model to simulate the urine patches. Two alternative methods to simulate the spatial distribution of urine patches were implemented and compared (Grid: spatially explicit, and Probabilistic: based on the probability of different temporal urination patterns). This paper describes the implementation of these two methods in connection with a Whole Farm Model; and compares the N leaching predictions with observed data. Two examples are provided, one analyzing the impact of urine patch overlap and another, the relative risk of N leaching at different times of urinary N deposition. The model showed good correlation and predictive ability between simulated annual N leaching results and observed data [R² = 94 %, mean relative prediction error (MRPE) = 10 % for Grid and R² = 72 %, MRPE = 20 % for Probabilistic]. The two methods produced similar results across an 8-year period for monthly and annual N leaching (R² = 96 %, MRPE = 10 % and R² = 86 %, MRPE = 8 %; respectively). Only 8 % of the paddock area was covered with multiple urinations during 1 year, but as much as 39 % of the total urine volume was deposited on overlapped patches. Systematically removing all urinary N for 1 month in either May or June reduced N leaching by approximately 20 %. Avoiding urinary N deposition during autumn or early winter could be highly effective in mitigating N leached during the following winter.     

Epitaxy of Si:C on Si(001) via methyldichlorosilane

Methyldichlorosilane (CH₃SiHCl₂) is compared to methylsilane (CH₃SiH₃) for vapor phase epitaxy of cubic silicon - carbon (NO :) (Si:C) alloys on Si (001). Parameters of interest are growth rate, percent carbon and crystallinity. Carbon incorporation efficiency and experimental window for epitaxial growth are similar for both precursors. The two precursors differ in Si contribution to the film growth rate.     

High molecular weight plasticizers in thermoplastic starch/polyethylene blends

In this study thermoplastic starch (TPS) was prepared with four different molecular weight polyol plasticizers: glycerol, sorbitol, diglycerol and polyglycerol. Diglycerol-TPS (DTPS) and polyglycerol-TPS (PTPS) show significantly lower moisture uptake and a higher temperature stability when compared to conventional glycerol-TPS (GTPS). TPS formulations were blended with HDPE at a concentration of 20 TPS/80 HDPE wt% and a range of interfacial modifier contents via a one-step extrusion process. The emulsification curves of the blends, which track the volume and number average diameter of the dispersed TPS domains with per cent interfacial modifier, show significantly different profiles and a non-correspondence between the d _n and d _v values at the critical concentration for interfacial saturation. The addition of small amounts of interfacial modifier to the blends prepared with diglycerol and polyglycerol results in TPS dispersed phases of wide polydispersity with droplets in the order of 200–300 nm coexisting with droplets of 5–7 µm. This wide polydispersity of TPS phase size can give insight into the mechanism of droplet formation in these systems with interfacial modifier and is indicative of an erosion-type mechanism, where small portions of the TPS droplet break off at the outer part of the droplet. Blends prepared with GTPS and sorbitol-TPS do not display this behaviour and show a more classic correspondence of d _n and d _v at the critical concentration. Dynamic mechanical analysis shows miscible behaviour for DTPS and PTPS and partially miscible behaviour for GTPS. This phenomenon was attributed to the presence of ether bonds in the chemical structure of diglycerol and polyglycerol. The increased chain flexibility and lower cohesive energy forces of diglycerol and polyglycerol lead to a more homogeneous TPS phase and consequently an erosion-type compatibilization at the interface. The mechanical properties of blends prepared with polyglycerol and diglycerol show a similar overall behaviour to glycerol.     

Scheduling of open-pit phosphate mine extraction

Open-pit deposits are often characterised by a stack of layers of different geological nature. Some layers are worthless while the ore of the others is of a varying economic value depending on grade. To reach a layer, it is necessary to have first removed the upper layers above the extraction zone. This action results in uncovering the layer in this particular place and in facilitating access to the layers below. This extraction process involves a series of 2–7 basic operations; each one is performed by a machine, some of which are able to perform up to three different operations. Ensuring the consistency of mining extraction scheduling over a few months, in order to meet known or forecast demand, is a challenging task. A mining extraction model based on mathematical programming is proposed but it is hardly usable, due to its size. Therefore, a model based on a Discrete Event Simulation, is created to test how ore supplies are affected by the tactical and operational decisions relating to the choice of parcels to be processed and to the allocation of machines to the different basic operations.     

Megaprojects as complex adaptive systems: The Hinkley point C case

Megaprojects are complex projects which impact millions of people, involve public and private stakeholders, and present challenges related to decision making and performance shortfalls. They are relevant cases for studying faulty management thinking as well as performance evolutions and self-organizing dynamics. Our paper builds on the theory of Complex Adaptive Systems (CAS) to understand and model processes of evolution in the Hinkley Point C nuclear power plant megaproject. The results show that CAS properties apply to megaproject changes and provide a theoretical and practical framework for examining and modeling megaproject management dynamics. We designed a research methodology combining content analysis and historical research for its relevance in conducting organizational research in conditions of complexity and non-linearity. This original research design makes it possible to conduct causal analyses of relations between key megaproject events and thus build models of evolution dynamics in stakeholder success expectations, change mechanisms in the implementation of project outputs, and self-organizing patterns.     

Gastric Cancer: Advances in Carcinogenesis Research and New Therapeutic Strategies

Gastric cancer’s bad incidence, prognosis, cellular and molecular heterogeneity amongst others make this disease a major health issue worldwide. Understanding this affliction is a priority for proper patients’ management and for the development of efficient therapeutical strategies. This review gives an overview of major scientific advances, made during the past 5-years, to improve the comprehension of gastric adenocarcinoma. A focus was made on the different actors of gastric carcinogenesis, including, Helicobacter pylori cancer stem cells, tumour microenvironment and microbiota. New and recent potential biomarkers were assessed as well as emerging therapeutical strategies involving cancer stem cells targeting as well as immunotherapy. Finally, recent experimental models to study this highly complex disease were discussed, highlighting the importance of gastric cancer understanding in the hard-fought struggle against cancer relapse, metastasis and bad prognosis.     

Flexibility and binding affinity in protein–ligand,protein–protein and multi-component protein interactions: limitations of current computational approaches

The recognition process between a protein and a partner represents a significant theoretical challenge. In silico structure-based drug design carried out with nothing more than the three-dimensional structure of the protein has led to the introduction of many compounds into clinical trials and numerous drug approvals. Central to guiding the discovery process is to recognize active among non-active compounds. While large-scale computer simulations of compounds taken from a library (virtual screening) or designed de novo are highly desirable in the post-genomic area, many technical problems remain to be adequately addressed. This article presents an overview and discusses the limits of current computational methods for predicting the correct binding pose and accurate binding affinity. It also presents the performances of the most popular algorithms for exploring binary and multi-body protein interactions.     

Cereal‐based fermented foods in developing countries: ancient foods for modern research

Cereal‐based fermented foods are major contributors to energy intake in developing countries (DC). Their microbiota is dominated by lactic acid bacteria and has been extensively investigated. Diversity studies have been facilitated by molecular methods enabling genotyping of isolates; the rapid development of ‘omics’ approaches should facilitate more comprehensive studies to describe the relation between microbial diversity, cell physiology and product characteristics. Also, the link between the food microbiota and health benefits, in particular in nutrition, should be investigated. There is a need to encourage researches in the field of DC cereal‐based foods in direction of more mechanistic approaches.     

Safety-enhanced Collaborative Framework for Tele-operated Minimally Invasive Surgery Using a 7-DoF Torque-controlled Robot

International Journal of Control, Automation and Systems - In this paper, a safety-enhanced collaborative control framework is proposed for tele-operated minimally invasive surgery (MIS) using a...