Complex coastal change in response to autogenic basin infilling: An example from a sub-tropical Holocene strandplain

Thick bay-fill sequences that often culminate in strandplain development serve as important sedimentary archives of land-ocean interaction, although distinguishing between internal and external forcings is an ongoing challenge. This study employs sediment cores, ground-penetrating radar surveys, radiocarbon dates, palaeogeographic reconstructions and hydrodynamic modelling to explore the role of autogenic processes - notably a reduction in wave energy in response to coastal embayment infilling - in coastal evolution and shoreline morphodynamics. Following a regional 2 to 4m highstand at ca 58ka, the 75km(2) Tijucas Strandplain in southern Brazil built from fluvial sediments deposited into a semi-enclosed bay. Holocene regressive deposits are underlain by fluvial sands and a Pleistocene transgressive-regressive sequence, and backed by a highstand barrier-island. The strandplain is immediately underlain by 5 to 16m of seaward-thickening, fluvially derived, Holocene-age, basin-fill mud. Several trends are observed from the landward (oldest) to the seaward (youngest) sections of the strandplain: (i) the upper shoreface and foreshore become finer and thinner and shift from sand-dominated to mud-dominated; (ii) beachface slopes decrease from \u3e11 degrees to ca 7 degrees; and (iii) progradation rates increase from 04 to 18myr(-1). Hydrodynamic modelling demonstrates a correlation between progressive shoaling of Tijucas Bay driven by sea-level fall and sediment infilling and a decrease in onshore wave-energy transport from 18 to 4kWm(-1). The combination of allogenic (sediment supply, falling relative sea-level and geology) and autogenic (decrease in wave energy due to bay shoaling) processes drove the development of a regressive system with characteristics that are rare, if not unique, in the Holocene and rock records. These findings demonstrate the complexities in architecture styles of highstand and regressive systems tracts. Furthermore, this article highlights the diverse internal and external processes and feedbacks responsible for the development of these intricate marginal marine sedimentary systems

Computational Optimal Transport and Filtering on Riemannian manifolds

In this paper we extend recent developments in computational optimal transport to the setting of Riemannian manifolds. In particular, we show how to learn optimal transport maps from samples that relate probability distributions defined on manifolds. Specializing these maps for sampling conditional probability distributions provides an ensemble approach for solving nonlinear filtering problems defined on such geometries. The proposed computational methodology is illustrated with examples of transport and nonlinear filtering on Lie groups, including the circle $S^1$, the special Euclidean group $SE(2)$, and the special orthogonal group $SO(3)$.Comment: 6 pages, 7 figure

Computational Studies on Microreactors for the Decomposition of Formic Acid for Hydrogen Production Using Heterogeneous Catalysts

Sustainable alternatives to conventional fuels have emerged recently, focusing on a hydrogen-based economy. The idea of using hydrogen (H2) as an energy carrier is very promising due to its zero-emission properties. The present study investigates the formic acid (FA) decomposition for H2 generation using a commercial 5 wt.% Pd/C catalyst. Three different 2D microreactor configurations (packed bed, single membrane, and double membrane) were studied using computational fluid dynamics (CFD). Parameters such as temperature, porosity, concentration, and flow rate of reactant were investigated. The packed bed configuration resulted in high conversions, but due to catalyst poisoning by carbon monoxide (CO), the catalytic activity decreased with time. For the single and double membrane microreactors, the same trends were observed, but the double membrane microreactor showed superior performance compared with the other configurations. Conversions higher than 80% were achieved, and even though deactivation decreased the conversion after 1 h of reaction, the selective removal of CO from the system with the use of membranes lead to an increase in the conversion afterwards. These results prove that the incorporation of membranes in the system for the separation of CO is improving the efficiency of the microreactor

Computational Studies on Microreactors for the Decomposition of Formic Acid for Hydrogen Production Using Heterogeneous Catalysts

Sustainable alternatives to conventional fuels have emerged recently, focusing on a hydrogen-based economy. The idea of using hydrogen (H2) as an energy carrier is very promising due to its zero-emission properties. The present study investigates the formic acid (FA) decomposition for H2 generation using a commercial 5 wt.% Pd/C catalyst. Three different 2D microreactor configurations (packed bed, single membrane, and double membrane) were studied using computational fluid dynamics (CFD). Parameters such as temperature, porosity, concentration, and flow rate of reactant were investigated. The packed bed configuration resulted in high conversions, but due to catalyst poisoning by carbon monoxide (CO), the catalytic activity decreased with time. For the single and double membrane microreactors, the same trends were observed, but the double membrane microreactor showed superior performance compared with the other configurations. Conversions higher than 80% were achieved, and even though deactivation decreased the conversion after 1 h of reaction, the selective removal of CO from the system with the use of membranes lead to an increase in the conversion afterwards. These results prove that the incorporation of membranes in the system for the separation of CO is improving the efficiency of the microreactor

Physical properties and biocompatibility effects of doping SiO2 and TiO2 into phosphate-based glass for bone tissue engineering

Phosphate glass is continuing to gain more attention as potential bone substitutes. The ternary (P2O5-CaO-Na2O) is investigated in terms of both physical properties and biocompatibility by doping different percentages of SiO2 and TiO2. Two groups were prepared; the first has different percentages of TiO2 and SiO2, whereas the second group compositions have 5 mol% TiO2 and 5 mol% SiO2 being added to compensate the network-forming oxide P2O5 and the network-modifying oxide CaO. Density, mass loss, pH, DTA, XRD, and cation release experiments were performed to study the physicochemical properties of the compositions, while MG63 and hMS cells were used within in vitro cell culture to study their biocompatibility. Results showed that an increase in TiO2 content correlated with an increase in glass density, decreased mass loss, increased trend of Tg and Tm values, and Na+ and Ca2+ release in group 1. There was no improvement in the MG63 viability or the ability of hMSCs to differentiate into osteoblasts where TiO2 decreased in favour of SiO2. Furthermore, in group 2, 50P2O5-25CaO was less dense than 45P2O5-30CaO, degraded dramatically less, had lower Tg and Tm values and released less Na+ and Ca(2+). The synergistic effect of doping 5 mol% TiO2 and 5 mol% SiO2 increased the MG63 viability in both compositions and was found 45P2O5-30CaO to have promising results in terms of the ability of hMSCs to differentiate into osteoblasts. To conclude, substituting TiO2 in place of SiO2 improved the physical properties and the biocompatibility of (P2O5-CaO-Na2O) glass system, whereas doping 5 mol% SiO2 and 5 mol% TiO2 together in place of P2O5 and CaO had a synergistic effect in controlling their degradation rate and improving their biological responses

Optical‐mode structure of micropillar microcavities containing a fluorescent conjugated polymer

The light emission from a series of micropillar microcavities containing a fluorescent, red‐emitting conjugated polymer, is explored. Cavities are fabricated by defining two dielectric mirrors either side of a polymer active region. Focused ion‐beam (FIB) lithography is then used to etch pillar structures into the planar cavity having diameters between 1 and 11 µm. The photoluminescence (PL) emission of the cavities is characterized using real‐space tomographic and Fourier‐space imaging techniques, with emission shown to be quantized into a mode‐structure resulting from both vertical and lateral optical confinement within the pillar. The optical‐confinement effects which result in a blue‐shift of the fundamental mode as the pillar diameter is reduced is demonstrated, with a model applied to describe the energy and distribution of the confined optical modes

Factors affecting interprofessional teamwork in emergency department care of polytrauma patients : results of an exploratory study

Considering that traumatic injuries are the leading cause of death among young adults across the globe, emergency department care of polytrauma patients is a crucial aspect of optimized care and premature death prevention. Unfortunately, many studies have highlighted important gaps in collaboration among different trauma team professionals, posing a major quality of care challenge. Using the conceptual framework for interprofessional teamwork (IPT) of Reeves, Lewin, Espin, and Zwarenstein (2010), the aim of this qualitative descriptive exploratory study was to better understand IPT from the perspective of health professionals in emergency department care of polytrauma patients, specifically by identifying factors that facilitate and impede IPT. Data was collected from a sample of seven health professionals involved in the care of polytrauma patients, through individual interviews and a focus group. In a second phase, two structured observations of polytrauma patient care were conducted. Following a thematic analysis, results show multiple factors affecting IPT, which can be divided into five broad categories: individual, relational, processual, organizational and contextual. Individual factors, a category that is not part of the conceptual framework of Reeves et al. (2010), also emerged as playing a major part in IPT

No evidence for selective follicle abortion underlying primary sex ratio adjustment in pigeons

Primary sex ratio adjustment in birds has been extensively studied, yet the underlying physiological mechanisms are far from understood. Avian females are the heterogametic sex (ZW), and the future sex of the offspring is determined at chromosome segregation during meiosis I, shortly before the oocyte is ovulated. Assuming that the mother can detect the sex of the developing oocyte before ovulation, it has been suggested that a follicle of the un-preferred sex could selectively be induced to become atretic and regress instead of being ovulated (selective follicle abortion). This potential mechanism has been proposed to underlie biased primary sex ratios in birds, including the homing pigeon (Columba livia domestica), which produces a modal clutch size of two eggs. However, without replacement by an additional, already mature follicle, abortion of a preovulatory follicle would most likely result in either reduced clutch sizes or laying gaps, since a not-yet-recruited follicle still needed to undergo the whole maturation phase. In the current study we killed female pigeons, which were adjusting embryo sex of first eggs according to change in body mass. We examined ovaries for signs of follicle abortion but did not find any supporting evidence. All females produced one or two mature follicles but only two out of the 56 experimental birds produced an additional third mature follicle. Therefore, our results do not corroborate the hypothesis that pigeon mothers manipulate primary offspring sex by selectively aborting follicles of the un-preferred sex

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine: Brussels, Belgium. 15-18 March 2016.

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]