An analysis of the distribution and abundance of sandeels in grey seals' foraging hotspots around the Inner Hebrides, West Scotland

Quantifying the abundance and distribution of sandeels in grey seal foraging areas will provide an improved understanding of habitat use of grey seals on the West Coast of Scotland. The lesser sandeel, Ammodytes marinus, is a key food for many seabirds and seals, and is also the target of the largest single-species fishery in the North Sea (Furness, 2002).Fisheries acoustic data were collected during 2 cruises in May 2004 and July 2004 around the Inner Hebrides, West Scotland. A fully calibrated EK500 echosounder was used, operating at two frequencies (38kHz and 120kHz). The collected data was processed using SonarData Echoview software. Acoustic identification of sandeels was established by using a dB difference algorithm (?MVBS = MVBS38 - MVBS120; where ?MVBS < -1 indicated sandeels). The resulting Nautical Area Backscattering Coefficient (NASC) was integrated for each 0.5 nmi interval and converted to a relative estimate of mean sandeel density in seal foraging areas. Information on the spatial distribution and movements of 34 grey seals around the West Coast of Scotland in 2003 and 2004 have been collected by SMRU using Satellite Relay Data Loggers (SDRL) and will be used to compare sandeel densities and distribution in areas of high seal usage.The results indicated that the distribution of sandeels was extremely patchy along transects and the cruise track. A comparison of the relative abundance of sandeels in foraging areas showed that densities vary extremely between these areas. Highest densities of sandeels were recorded East of Tiree on the 14th of May and in Stanton Banks on the 17th of July.Future research will involve establishing a correlation between seal usage of foraging areas and sandeel abundance and distribution. In addition, the analysis of other fish species and zooplankton in these areas will contribute to a further understanding of foraging strategies of grey seals. The capabilities of underwater acoustic research and their implementation in ecosystem-based studies are constantly evolving. Interdisciplinary research should be encouraged in order to provide useful insights in ecosystem dynamics but also to benefit fisheries and conservation management strategies

Extreme UK rainfall and natural climate variability: combining models and data

The return periods for extreme events are estimated from observational datasets. Often those datasets are relatively short in comparison to timescales of natural climate variability; potentially introducing a systematic bias into the extreme estimates. Here we combine observations with global climate models to show that this bias is statistically insignificant for the case of extreme UK-wide rainfall estimates. This is unlikely to hold for other locations and spatial scales, yet the methodology we have developed provides a simple approach to quantify the bias for other cases

Reduced Atlantic variability in the mid-Pliocene

This study evaluates interannual-to-decadal sea surface temperature (SST) variability in the mid-Pliocene Warm Period within the Pliocene Model Intercomparison Project (PlioMIP). Our results show significantly reduced variability at low latitudes and mid-latitudes in the mid-Pliocene in comparison to the pre-industrial climate. At high latitudes of both hemispheres, the SST variability has increased. Latitudinal changes are likely driven by changes in the meridional SST gradient. Results with respect to the main Atlantic SST modes of variability show that the Atlantic Multidecadal Variability shifts southward and expands eastward due to a southward shift in the North Atlantic Drift position. The Atlantic Meridional Mode amplitude weakens due to increased SST gradient between its two poles. The South Atlantic Subtropical Dipole significantly shifts its southwestern pole towards the South American coast. Moreover, all Atlantic modes of variability have shifted their respective frequencies towards lower values. Our analyses on the PlioMIP simulation results provide a useful constraint in future projections associated with a warmer world when assessing Atlantic SST variability

The Limited Role of Mutually Unbiased Product Bases in Dimension Six

We show that a complete set of seven mutually unbiased bases in dimension six, if it exists, cannot contain more than one product basis.Comment: 8 pages, identical to published versio

Inter-annual variability in the tropical Atlantic from the Last Glacial Maximum into future climate projections simulated by CMIP5/PMIP3

Tropical Atlantic variability (TAV) plays an important role in driving year-to-year changes in rainfall over Africa and South America. In this study, its response to global climate change is investigated through a series of multi-model experiments. We explore the leading modes of TAV during the historical, Last Glacial Maximum, mid-Holocene, and future simulations in the multi-model ensemble known as PMIP3/CMIP5. Despite their known sea surface temperature biases, most of the models are able to capture the tropical Atlantic's two leading modes of SST variability patterns - the Atlantic Meridional Mode (AMM) and the Atlantic zonal mode (also called the Atlantic Niño or ATL3). The ensemble suggests that AMM amplitude was less during the mid-Holocene and increased during the Last Glacial Maximum, but is equivocal about future changes. ATL3 appears stronger under both the Last Glacial Maximum and future climate changes, with no consistent message about the mid-Holocene. The patterns and the regions under the influence of the two modes alter a little under climate change in concert with changes in the mean climate state. In the future climate experiment, the equatorial mode weakens, and the whole Northern Hemisphere warms up, while the South Atlantic displays a hemisphere-wide weak oscillating pattern. For the LGM, the AMM projects onto a pattern that resembles the pan-Atlantic decadal oscillation. No robust relationships between the amplitude of the zonal and meridional temperature gradients and their respective variability was found

Statistical mechanics of multipartite entanglement

We characterize the multipartite entanglement of a system of n qubits in terms of the distribution function of the bipartite purity over all balanced bipartitions. We search for those (maximally multipartite entangled) states whose purity is minimum for all bipartitions and recast this optimization problem into a problem of statistical mechanics.Comment: final versio

A cannabigerol-rich Cannabis sativa extract, devoid of ∆9-tetrahydrocannabinol, elicits hyperphagia in rats

Objective: Non-psychoactive phytocannabinoids (pCBs) from Cannabis sativa may represent novel therapeutic options for cachexia due to their pleiotropic pharmacological activities, including appetite stimulation. We have recently shown that purified cannabigerol (CBG) is a novel appetite stimulant in rats. As standardised extracts from Cannabis chemotypes dominant in one pCB (botanical drug substances (BDS)) often show greater efficacy and/or potency than purified pCBs, we investigated the effects of a CBG-rich BDS, devoid of psychoactive ∆9-THC, on feeding behaviour. Methods: Following a 2 hour pre-feed satiation procedure, 16 male Lister-hooded rats were administered CBG-BDS (at 30-240 mg/kg) or vehicle. Food intake, meal pattern microstructure and locomotor activity were recorded over 2 hours. Results: Total food intake was increased by 120 and 240mg/kg CBG-BDS vs vehicle (1.53g and 1.36g, respectively, vs 0.56g; p<0.05 and p<0.01). Latency to feeding onset was dose-dependently decreased by all doses (p<0.05-0.01), and 120 and 240mg/kg doses increased both the number of meals consumed (p<0.01) and cumulative size of the first 2 meals (p<0.05 and p<.0.01). No significant effect was observed on ambulatory activity or rearing behaviour. Conclusions: CBG-BDS is a novel appetite stimulant, which may have greater potency than purified CBG, despite the absence of ∆9-THC in the extract

Multi-Qubit Systems: Highly Entangled States and Entanglement Distribution

A comparison is made of various searching procedures, based upon different entanglement measures or entanglement indicators, for highly entangled multi-qubits states. In particular, our present results are compared with those recently reported by Brown et al. [J. Phys. A: Math. Gen. 38 (2005) 1119]. The statistical distribution of entanglement values for the aforementioned multi-qubit systems is also explored.Comment: 24 pages, 3 figure

Potential use of oxygen as a metabolic biosensor in combination with T2*-weighted MRI to define the ischemic penumbra

We describe a novel magnetic resonance imaging technique for detecting metabolism indirectly through changes in oxyhemoglobin:deoxyhemoglobin ratios and T2* signal change during ‘oxygen challenge’ (OC, 5 mins 100% O2). During OC, T2* increase reflects O2 binding to deoxyhemoglobin, which is formed when metabolizing tissues take up oxygen. Here OC has been applied to identify tissue metabolism within the ischemic brain. Permanent middle cerebral artery occlusion was induced in rats. In series 1 scanning (n=5), diffusion-weighted imaging (DWI) was performed, followed by echo-planar T2* acquired during OC and perfusion-weighted imaging (PWI, arterial spin labeling). Oxygen challenge induced a T2* signal increase of 1.8%, 3.7%, and 0.24% in the contralateral cortex, ipsilateral cortex within the PWI/DWI mismatch zone, and ischemic core, respectively. T2* and apparent diffusion coefficient (ADC) map coregistration revealed that the T2* signal increase extended into the ADC lesion (3.4%). In series 2 (n=5), FLASH T2* and ADC maps coregistered with histology revealed a T2* signal increase of 4.9% in the histologically defined border zone (55% normal neuronal morphology, located within the ADC lesion boundary) compared with a 0.7% increase in the cortical ischemic core (92% neuronal ischemic cell change, core ADC lesion). Oxygen challenge has potential clinical utility and, by distinguishing metabolically active and inactive tissues within hypoperfused regions, could provide a more precise assessment of penumbra

Affine Constellations Without Mutually Unbiased Counterparts

It has been conjectured that a complete set of mutually unbiased bases in a space of dimension d exists if and only if there is an affine plane of order d. We introduce affine constellations and compare their existence properties with those of mutually unbiased constellations, mostly in dimension six. The observed discrepancies make a deeper relation between the two existence problems unlikely.Comment: 8 page