Effects of El Niño events on energy demand and egg production of rockfish (Scorpaenidae: Sebastes): a bioenergetics approach

Fish bioenergetics models estimate relationships between energy budgets and environmental and physiological variables. This study presents a generic rockfish (Sebastes) bioenergetics model and estimates energy consumption by northern California blue rockf ish (S. mystinus) under average (baseline) and El Niño conditions. Compared to males, female S. mystinus required more energy because they were larger and had greater reproductive costs. When El Niño conditions (warmer temperatures; lower growth, condition, and fecundity) were experienced every 3−7 years, energy consumption decreased on an individual and a per-recruit basis in relation to baseline conditions, but the decrease was minor (<4% at the individual scale, <7% at the per-recruit scale) compared to decreases in female egg production (12−19% at the individual scale, 15−23% at the per-recruit scale). When mortality in per-recruit models was increased by adding fishing, energy consumption in El Niño models grew more similar to that seen in the baseline model. However, egg production decreased significantly — an effect exacerbated by the frequency of El Niño events. Sensitivity analyses showed that energy consumption estimates were most sensitive to respiration parameters, energy density, and female fecundity, and that estimated consumption increased as parameter uncertainty increased. This model provides a means of understanding rockfish trophic ecology in the context of community structure and environmental change by synthesizing metabolic, demographic, and environmental information. Future research should focus on acquiring such information so that models like the bioenergetics model can be used to estimate the effect of climate change, community shifts, and different harvesting strategies on rockfish energy demands

Magnetic mirror cavities as THz radiation sources and a means of quantifying radiation friction

We propose a radiation source based on a magnetic mirror cavity. Relativistic electrons are simulated entering the cavity and their trajectories and resulting emission spectra are calculated. The uniformity of the particle orbits is found to result in a frequency comb in terahertz range, the precise energies of which are tuneable by varying the electron's $\gamma$-factor. For very high energy particles radiation friction causes the spectral harmonics to broaden and we suggest this as a possible way to verify competing classical equations of motion.Comment: 8 pages, 10 figure

Vision and its Relationship to Novel Behaviour in St. Lawrence River Greenland Sharks, Somniosus microcephalus

Rarely observed Greenland Sharks, Somniosus microcephalus, were recorded at shallow depths by divers employing underwater video in the St. Lawrence River, in association with a seasonal concentration of Capelin (Mallotus villosus) in May-June 2003. We recorded unique proximity-induced display motor patterns in these sharks, which have not been recorded in underwater observations of Arctic Greenland Sharks. Arctic sharks have a high incidence of blindness due to an ocular copepod parasite, Ommatokoita elongata. The absence of parasite-induced blindness in St. Lawrence Greenland Sharks, in contrast to endemic blindness in the Arctic population, may allow sharks in this region to more readily visually recognize the presence of conspecifics and potential prey. Improved visual acuity may therefore allow St. Lawrence River sharks to express a different behavioural repertoire than Arctic sharks, with resulting changes in intra- and inter-specific aggression and predatory behaviour

Re-introduction of structurally complex wood jams promotes channel and habitat recovery from overwidening: Implications for river conservation

Copyright © 2017 John Wiley & Sons, Ltd. Large wood is a powerful geomorphic agent in rivers, providing important habitat functions for a range of aquatic organisms, but has been subject to a long history of removal. Internationally, approaches to river restoration are increasingly incorporating large wood features, but generally favour simple flow deflectors (e.g. single logs, stripped of branches and anchored in place) over more complex structures that more accurately mimic natural wood jams. This paper explores channel response to wood-based restoration of an overwidened lowland chalk stream that incorporated whole felled trees. Hydraulics, sediment, topography and vegetation data were assessed for a 3year period for two restored reaches: an upstream reach where pre-restoration baseline data were obtained, and a downstream reach restored before data collection. Where pre-restoration data were available, the introduction of wood jams generated sediment deposition within jams leading to the development of vegetated marginal ‘benches’ and bed scour in adjacent areas of flow convergence. Patterns were less clear in the downstream reach, where restoration design was less ambitious and outcomes may have been affected by subsequent restoration work upstream. The results indicate that reintroduction of large wood (whole trees), can promote channel and habitat recovery from overwidening in lowland rivers, creating important ecological benefits through the provision of structurally complex marginal habitat and associated food resources. Longer-term assessments are required to establish whether the trajectories of change are persistent. The work emphasizes the effectiveness of restoration approaches that aim to ‘work with nature’. The ambitious design, incorporating structurally complex wood jams, was also low-cost, using materials available from the river corridor (existing riparian trees). Furthermore, ecosystem engineering effects were amplified by the colonization of wood jams by aquatic vegetation. The approach should, therefore, be transferable to other lowland rivers, subject to wider catchment constraints

A Note on Fluxes and Superpotentials in M-theory Compactifications on Manifolds of G_2 Holonomy

We consider the breaking of N=1 supersymmetry by non-zero G-flux when M-theory is compactified on a smooth manifold X of G_2 holonomy. Gukov has proposed a superpotential W to describe this breaking in the low-energy effective theory. We check this proposal by comparing the bosonic potential implied by W with the corresponding potential deduced from the eleven-dimensional supergravity action. One interesting aspect of this check is that, though W depends explicitly only on G-flux supported on X, W also describes the breaking of supersymmetry by G-flux transverse to X.Comment: 15 pages, harvmac, v2: reference adde

Cardiac Catheterisation and Intervention on ECMO

Cardiac catheterisation is an essential tool to evaluate patients who require ECMO support for severe haemodynamic impairment. In the first part of this chapter, we describe the equipment, teamwork, expertise, techniques and precautions that are necessary to carry out safe and effective cardiac catheterisation on ECMO. We have moved on from an early pioneering era to a stage where the multidisciplinary team approach has been worked out in detail, using operational procedures that deal with the technical challenges and minimise the risks of ECMO catheterisation and intervention. In the second part of the chapter, we explain in detail how cardiac catheterisation and intervention on ECMO contribute to the management of (1) post-operative congenital heart disease patients, (2) cardiac patients who suffer sudden haemodynamic deterioration, (3) patients with low cardiac output who require left heart decompression because of extracorporeal support, (4) patients with haemodynamically unstable arrhythmias and (5) haemodynamically unstable patients who require percutaneous coronary intervention. We also provide state-of-the-art information on the elective use of ECMO to support congenital and structural catheter interventions. Acute survival and long-term outcome are now related to the underlying conditions rather than complications of the catheterisation procedure itself

Western North Pacific Tropical Cyclone Tracks in CMIP5 Models: Statistical Assessment Using a Model-Independent Detection and Tracking Scheme

Past studies have shown that tropical cyclone (TC) projection results can be sensitive to different types of TC tracking schemes, and that the relative adjustments of detection criteria to accommodate different models may not necessarily provide a consistent platform for comparison of projection results. Here, future climate projections of TC activity in the western North Pacific basin (WNP, defined from 0°–50°N and 100°E–180°) are assessed with a model-independent detection and tracking scheme. This scheme is applied to models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) forced under the historical and representative concentration pathway 8.5 (RCP8.5) conditions. TC tracks from the observed records and independent models are analyzed simultaneously with a curve-clustering algorithm, allowing observed and model tracks to be projected onto the same set of clusters (k = 9). Four of the nine clusters were projected to undergo significant changes in TC frequency. Straight-moving TCs in the South China Sea were projected to significantly decrease. Projected increases in TC frequency were found poleward of 20°N and east of 160°E, consistent with changes in ascending motion, as well as vertical wind shear and relative humidity respectively. Projections of TC track exposure indicated significant reductions for southern China and the Philippines and significant increases for the Korean peninsula and Japan, although very few model TCs reached the latter subtropical regions in comparison to the observations. The use of a fundamentally different detection methodology that overcomes the detector/tracker bias gives increased certainty to projections as best as low-resolution simulations can offer

Short-term safety outcomes of mastectomy and immediate pre-pectoral implant-based breast reconstruction:Pre-BRA prospective multicentre cohort study

Background: Prepectoral breast reconstruction (PPBR) has recently been introduced to reduce postoperative pain and improve cosmetic outcomes in women having implant-based procedures. High-quality evidence to support the practice of PPBR, however, is lacking. Pre-BRA is an IDEAL stage 2a/2b study that aimed to establish the safety, effectiveness, and stability of PPBR before definitive evaluation in an RCT. The short-Term safety endpoints at 3 months after surgery are reported here. Methods: Consecutive patients electing to undergo immediate PPBR at participating UK centres between July 2019 and December 2020 were invited to participate. Demographic, operative, oncology, and complication data were collected. The primary outcome was implant loss at 3 months. Other outcomes of interest included readmission, reoperation, and infection. Results: Some 347 women underwent 424 immediate implant-based reconstructions at 40 centres. Most were single-stage direct-To-implant (357, 84.2 per cent) biological mesh-Assisted (341, 80.4 per cent) procedures. Conversion to subpectoral reconstruction was necessary in four patients (0.9 per cent) owing to poor skin-flap quality. Of the 343 women who underwent PPBR, 144 (42.0 per cent) experienced at least one postoperative complication. Implant loss occurred in 28 women (8.2 per cent), 67 (19.5 per cent) experienced an infection, 60 (17.5 per cent) were readmitted for a complication, and 55 (16.0 per cent) required reoperation within 3 months of reconstruction. Conclusion: Complication rates following PPBR are high and implant loss is comparable to that associated with subpectoral mesh-Assisted implant-based techniques. These findings support the need for a well-designed RCT comparing prepectoral and subpectoral reconstruction to establish best practice for implant-based breast reconstruction

The intensity dependent mass shift: existence, universality and detection

The electron mass shift in a laser field has long remained an elusive concept. We show that the mass shift can exist in pulses but that it is neither unique nor universal: it can be reduced by pulse shaping. We show also that the detection of mass shift effects in laser-particle scattering experiments is feasible with current technology, even allowing for the transverse structure of realistic beams.Comment: 5 pages, 4 figures. V2: references added, introduction expande