Not all jellyfish are equal: isotopic evidence for inter- and intraspecific variation in jellyfish trophic ecology

Jellyfish are highly topical within studies of pelagic food-webs and there is a growing realisation that their role is more complex than once thought. Efforts being made to include jellyfish within fisheries and ecosystem models are an important step forward, but our present understanding of their underlying trophic ecology can lead to their oversimplification in these models. Gelatinous zooplankton represent a polyphyletic assemblage spanning >2,000 species that inhabit coastal seas to the deep-ocean and employ a wide variety of foraging strategies. Despite this diversity, many contemporary modelling approaches include jellyfish as a single functional group feeding at one or two trophic levels at most. Recent reviews have drawn attention to this issue and highlighted the need for improved communication between biologists and theoreticians if this problem is to be overcome. We used stable isotopes to investigate the trophic ecology of three co-occurring scyphozoan jellyfish species (Aurelia aurita, Cyanea lamarckii and C. capillata) within a temperate, coastal food-web in the NE Atlantic. Using information on individual size, time of year and δ 13 C and δ 15 N stable isotope values, we examined: (1) whether all jellyfish could be considered as a single functional group, or showed distinct inter-specific differences in trophic ecology; (2) Were size-based shifts in trophic position, found previously in A. aurita, a common trait across species?; (3) When considered collectively, did the trophic position of three sympatric species remain constant over time? Differences in δ 15 N (trophic position) were evident between all three species, with size-based and temporal shifts in δ 15 N apparent in A. aurita and C. capillata. The isotopic niche width for all species combined increased throughout the season, reflecting temporal shifts in trophic position and seasonal succession in these gelatinous species. Taken together, these findings support previous assertions that jellyfish require more robust inclusion in marine fisheries or ecosystem models

Unravelling the macro-evolutionary ecology of fish–jellyfish associations: life in the ‘gingerbread house’

Fish–jellyfish interactions are important factors contributing to fish stock success. Jellyfish can compete with fish for food resources, or feed on fish eggs and larvae, which works to reduce survivorship and recruitment of fish species. However, jellyfish also provide habitat and space for developing larval and juvenile fish which use their hosts as means of protection from predators and feeding opportunities, helping to reduce fish mortality and increase recruitment. Yet, relatively little is known about the evolutionary dynamics and drivers of such associations which would allow for their more effective incorporation into ecosystem models. Here, we found that jellyfish association is a probable adaptive anti-predator strategy for juvenile fish, more likely to evolve in benthic (fish living on the sea floor), benthopelagic (fish living just above the bottom of the seafloor), and reef-associating species than those adapted to other marine habitats. We also found that jellyfish association likely preceded the evolution of a benthic, benthopelagic, and reef-associating lifestyle rather than its evolutionary consequence, as we originally hypothesized. Considering over two-thirds of the associating fish identified here are of economic importance, and the wide-scale occurrence and diversity of species involved, it is clear the formation of fish–jellyfish associations is an important but complex process in relation to the success of fish stocks globally

Snaking and isolas of localised states in bistable discrete lattices

We consider localised states in a discrete bistable Allen-Cahn equation. This model equation combines bistability and local cell-to-cell coupling in the simplest possible way. The existence of stable localised states is made possible by pinning to the underlying lattice; they do not exist in the equivalent continuum equation. In particular we address the existence of 'isolas': closed curves of solutions in the bifurcation diagram. Isolas appear for some non-periodic boundary conditions in one spatial dimension but seem to appear generically in two dimensions. We point out how features of the bifurcation diagram in 1D help to explain some (unintuitive) features of the bifurcation diagram in 2D.Comment: 14 page

High Linearity Millimeter Wave Power Amplifiers with Novel Linearizer Techniques

Millimeter-wave communications have experienced phenomenal growth in recent years when limited frequency spectrum is occupied by the ever-developing communication services. The power amplifier, as the key component in the transmitter/receiver module of communication systems, affects performance of the whole system directly and receives much attention. For minimized distortion and optimum system performance, the non-constant en- velope modulation schemes used in communication systems have challenging requirements on linearity. As linearity is related to communication quality directly, several linearization techniques, such as predistortion and feedforward, are applied to power amplifier design. Predistortion method has the advantages over other techniques in relatively simple struc- ture and reasonable linearity improvement. But current predistortion circuits have quite limited performance improvement and relatively large insertion loss, which indicate the need for further research. In most of millimeter-wave amplifier design, great effort has been spent on output power or gain, while linearity is often ignored. As almost all the predistortion circuits operate at the RF frequencies, the linearized millimeter-wave com- munication circuit is still relatively immature and very challenging. This project is dedicated to solve the linearity problem faced by millimeter-wave power amplifier in communication systems, which lacks of e®ective techniques in this field. Linearity improvement with the predistortion method will be the key issue in this project and some original ideas for predistortion circuit design will be applied to millimeter-wave amplifiers. In this thesis, several predistortion circuits with novel structure were proposed, which provide a new approach for linearity improvement for millimeter-wave power am- plifier. A millimeter-wave power ampli¯er for LMDS applications built on GaAs pHEMT technology was developed to a high engineering standard, which works as the test bench for linearization. Actual operation and parasitic elements at tens of gigahertz have been taken into consideration during the design. Firstly, two novel predistorter structures based on the amplifier were proposed, one is based on an amplifier with a fixed bias circuit and the other is based on an amplifier with a nonlinear signal dependant bias circuit. These novel structures can improve the linearity while improving other metrics simultaneously, which can effectively solve the problem of insertion loss faced by the conventional structures. Besides this, an original predistortion circuit design methodology derived from frequency to signal amplitude transformation was proposed. Based on this methodology, several transfer functions were proposed and related predistortion circuits were built to linearize the power amplifier. As this methodology is quite different from the traditional approach, it can improve the linearity signifficantly while other metrics are affected slightly and has a broad prospect for application

Acceptability of alginate enriched bread and its effect on fat digestion in humans

Lifestyle interventions and physical activity remain the cornerstone of obesity management, as pharmacological therapies (orlistat) are associated with gastrointestinal (GI) side effects. Combining orlistat with fibers can reduce side effects, improving compliance. Therefore, a fiber that inhibits lipase without side effects could help treat obesity. The aims of the present work were to assess whether alginate enriched bread could inhibit fat digestion, and assess the acceptability of alginate bread and its effect on GI wellbeing. A double-blind, randomised, controlled cross-over pilot study (NCT03350958) assessed the impact of an alginate bread meal on; lipid content in ileal effluent and circulating triacylglycerol levels. This was compared against the same meal with non-enriched (control) bread. GI wellbeing and acceptability of alginate bread was compared to control bread through daily wellbeing questionnaires and food diaries (NCT03477981). Control bread followed by alginate bread were consumed for two weeks respectively. Consumption of alginate bread reduced circulating triacylglycerol compared to control (2% reduction in AUC) and significantly increased lipid content in ileal effluent (3.8 g ± 1.6 after 210 min). There were no significant changes to GI wellbeing when comparing alginate bread to control bread. A significant increase in the feeling of fullness occurred with alginate bread compared to baseline and the first week of control bread consumption. This study showed that sustained consumption of alginate enriched bread does not alter GI wellbeing and can decrease lipolysis, increasing lipid leaving the small intestine. Further studies are required to demonstrate that reduced fat digestion through the action of alginate can reduce fat mass or body weight

Biological activity of alginate and its effect on pancreatic lipase inhibition as a potential treatment for obesity

Alginates are classed as a dietary fibre and have been shown to inhibit digestive enzymes in vitro, and therefore could be used as an obesity treatment. The current study aims to assess whether alginate in a bread vehicle maintains its inhibition properties despite cooking and digestion, and may therefore be used as a potential treatment for obesity. After 180 min in a model gut that replicates digestion in the mouth, stomach and small intestines alginate bread (AB), control bread (CB), CB with Manucol® DM alginate, free DM alginate and model gut solution were collected. DM, LFR 5/60 and SF200 were heated at 37 °C and 200 °C, with DM also heated at 50, 100 and 150 °C. Samples from the model gut and heated alginate were assessed for molecular size and inhibition properties using viscosity, gel filtration and a lipase turbidity assay. AB does not significantly increase viscosity in the model gut. Viscosity of alginate reduces beyond 100 °C, although alginate retains its inhibition properties up to 150 °C. Cooking into the bread does not reduce the molecular size of the alginate or affect its inhibition properties. These data demonstrate the robustness of alginates lipase inhibition despite the cooking process and digestion. Therefore adding alginate to a bread vehicle may have the potential in the treatment for obesity

Modular House Revival

The Modular House, located in Poly Canyon, has seen extensive damage since the last caretaker left nearly ten years ago. To prevent further damage and improve the safety and appeal of the structure, we are proposing a renovation of the existing building that removes the existing cladding and partitions. By the end of Spring Quarter 2017, the Modular House will have a guardrail system replacing the wood paneling on the walls and a new steel composite deck to replace the current flooring system. The structural steel framing system will remain as is

Modular House Project Narrative

The Modular House, located in Poly Canyon, has seen extensive damage since the last caretaker left nearly ten years ago. To prevent further damage and improve the safety and appeal of the structure, we are proposing a renovation of the existing building that removes the existing cladding and partitions. By the end of Spring Quarter 2017, the Modular House will have a guardrail system replacing the wood paneling on the walls and a new steel composite deck to replace the current flooring system. The structural steel framing system will remain as is