519 research outputs found
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
Integrable models for asymmetric Fermi superfluids: Emergence of a new exotic pairing phase
We introduce an exactly-solvable model to study the competition between the
Larkin-Ovchinnikov-Fulde-Ferrell (LOFF) and breached-pair superfluid in
strongly interacting ultracold asymmetric Fermi gases. One can thus investigate
homogeneous and inhomogeneous states on an equal footing and establish the
quantum phase diagram. For certain values of the filling and the interaction
strength, the model exhibits a new stable exotic pairing phase which combines
an inhomogeneous state with an interior gap to pair-excitations. It is proven
that this phase is the exact ground state in the strong coupling limit, while
numerical examples demonstrate that also at finite interaction strength it can
have lower energy than the breached-pair or LOFF states.Comment: Revised version accepted for publicatio
Ghosts, Strong Coupling and Accidental Symmetries in Massive Gravity
We show that the strong self-interaction of the scalar polarization of a
massive graviton can be understood in terms of the propagation of an extra
ghost-like degree of freedom, thus relating strong coupling to the sixth degree
of freedom discussed by Boulware and Deser in their Hamiltonian analysis of
massive gravity. This enables one to understand the Vainshtein recovery of
solutions of massless gravity as being due to the effect of the exchange of
this ghost which gets frozen at distances larger than the Vainshtein radius.
Inside this region, we can trust the two-field Lagrangian perturbatively, while
at larger distances one can use the higher derivative formulation. We also
compare massive gravity with other models, namely deconstructed theories of
gravity, as well as DGP model. In the latter case we argue that the Vainshtein
recovery process is of different nature, not involving a ghost degree of
freedom.Comment: 21 page
SHRIMP ion probe zircon geochronology and Sr and Nd isotope geochemistry for southern Longwood Range and Bluff Peninsula intrusive rocks of Southland, New Zealand
Permian–Jurassic ultramafic to felsic intrusive complexes at Bluff Peninsula and in the southern Longwood Range along the Southland coast represent a series of intraoceanic magmatic arcs with ages spanning a time interval of 110 m.y. New SHRIMP U-Pb zircon data for a quartz diorite from the Flat Hill complex, Bluff Peninsula, yield an age of 259 ± 4 Ma, consistent with other geochronological and paleontological evidence confirming a Late Permian age. The new data are consistent with an age of c. 260 Ma for the intrusive rocks of the Brook Street Terrane. SHRIMP U-Pb zircon ages for the southern Longwood Range confirm that intrusions become progressively younger from east to west across the complex. A gabbro at Oraka Point (eastern end of coastal section) has an age of 245 ± 4 Ma and shows virtually no evidence of zircon inheritance. The age is significantly different from that of the Brook Street Terrane intrusives. Zircon ages from the western parts of the section are younger and more varied (203–227 Ma), indicating more complex magmatic histories. A leucogabbro dike from Pahia Point gives the youngest emplacement age of 142 Ma, which is similar to published U-Pb zircon ages for the Anglem Complex and Paterson Group on Stewart Island
Regularization of Brane Induced Gravity
We study the regularization of theories of ``brane induced'' gravity in
codimension . The brane can be interpreted as a thin dielectric with a
large dielectric constant, embedded in a higher dimensional space. The kinetic
term for the higher dimensional graviton is enhanced over the brane. A four
dimensional gravitation is found on the brane at distances smaller than a
critical distance , and is due to the exchange of a massive resonant
graviton. The crossover scale is determined by the mass of the resonance.
The suppression of the couplings of light Kaluza-Klein modes to brane matter
results in a higher dimensional force law at large distances. We show that the
resulting theory is free of ghosts or tachyons.Comment: One reference added. To appear in PRD. 20 pages, 3 figure
Radiofrequency ablation and chemotherapy versus chemotherapy alone for locally advanced pancreatic cancer (PELICAN): study protocol for a randomized controlled trial
Quimioteràpia; Càncer de pàncrees localment avançat; Ablació per radiofreqüènciaQuimioterapia; Cáncer de páncreas localmente avanzado; Ablación por radiofrecuenciaChemotherapy; Locally advanced pancreatic cancer; Radiofrequency ablationBackground
Approximately 80% of patients with locally advanced pancreatic cancer (LAPC) are treated with chemotherapy, of whom approximately 10% undergo a resection. Cohort studies investigating local tumor ablation with radiofrequency ablation (RFA) have reported a promising overall survival of 26–34 months when given in a multimodal setting. However, randomized controlled trials (RCTs) investigating the effect of RFA in combination with chemotherapy in patients with LAPC are lacking.
Methods
The “Pancreatic Locally Advanced Unresectable Cancer Ablation” (PELICAN) trial is an international multicenter superiority RCT, initiated by the Dutch Pancreatic Cancer Group (DPCG). All patients with LAPC according to DPCG criteria, who start with FOLFIRINOX or (nab-paclitaxel/)gemcitabine, are screened for eligibility. Restaging is performed after completion of four cycles of FOLFIRINOX or two cycles of (nab-paclitaxel/)gemcitabine (i.e., 2 months of treatment), and the results are assessed within a nationwide online expert panel. Eligible patients with RECIST stable disease or objective response, in whom resection is not feasible, are randomized to RFA followed by chemotherapy or chemotherapy alone. In total, 228 patients will be included in 16 centers in The Netherlands and four other European centers. The primary endpoint is overall survival. Secondary endpoints include progression-free survival, RECIST response, CA 19.9 and CEA response, toxicity, quality of life, pain, costs, and immunomodulatory effects of RFA.
Discussion
The PELICAN RCT aims to assess whether the combination of chemotherapy and RFA improves the overall survival when compared to chemotherapy alone, in patients with LAPC with no progression of disease following 2 months of systemic treatment.Olympus Netherlands BV supported the investigator-initiated PELICAN trial with material support by providing the RFA generators and electrodes for the study. They did not have and will not have any influence on the trial design, data collection, interpretation of the data, manuscript development, or decision to publish. Furthermore, the study protocol has undergone full external peer review and received a data management and monitoring grant from the Dutch Cancer Society (grant number 2014-7244)
Continuous Time Quantum Monte Carlo Method for Fermions: Beyond Auxiliary Field Framework
Numerically exact continuous-time Quantum Monte Carlo algorithm for finite
fermionic systems with non-local interactions is proposed. The scheme is
particularly applicable for general multi-band time-dependent correlations
since it does not invoke Hubbard-Stratonovich transformation. The present
determinantal grand-canonical method is based on a stochastic series expansion
for the partition function in the interaction representation. The results for
the Green function and for the time-dependent susceptibility of multi-orbital
super-symmetric impurity model with a spin-flip interaction are presented
Brane-bulk matter relation for a purely conical codimension-2 brane world
We study gravity on an infinitely thin codimension-2 brane world, with purely
conical singularities and in the presence of an induced gravity term on the
brane. We show that in this approximation, the energy momentum tensor of the
bulk is strongly related to the energy momentum tensor of the brane and thus
the gravity dynamics on the brane are induced by the bulk content. This is in
contrast with the gravity dynamics on a codimension-1 brane. We show how this
strong result is relaxed after including a Gauss-Bonnet term in the bulk.Comment: 12 pages, mistake corrected, references adde
TRAIL regulatory receptors constrain human hepatic stellate cell apoptosis
This work was funded by UCLH NIHR BRC (sample collection), Wellcome Trust Investigator award (MKM) and
Clinical Research Training Fellowship (USG); Medical Research Council grant (MKM) and Clinician Scientist
Fellowship (DP); EASL fellowship (IO); National Health and Medical Research Council Australia (KPS)
Foaming and air-water interfacial characteristics of solutions containing both gluten hydrolysate and egg white protein
Enzymatically hydrolyzed wheat gluten can be a viable alternative for traditional animal-based foam stabilizing proteins in food systems. Gluten hydrolysates (GHs) can be considered for (partially) replacing surface-active food proteins such as those of egg white (EW). We here studied the foaming and air-water (A-W) interfacial characteristics of mixed GH + EW protein solutions. GH solutions had much higher (P < 0.05) foaming capacities than EW solutions, while the latter had much higher (P < 0.05) foam stability than the former. When only one sixth of EW proteins was replaced by GHs, the foaming capacity of the mixtures was as high as or higher than that of the GH solutions. Furthermore, when half of the EW protein was replaced by GH, the mixtures still had high foam stability. It thus seems that both GH and EW proteins contribute positively to the foaming characteristics of the mixtures. However, measurements of the early stages of diffusion to and adsorption at the interface, plus measurements of surface dilatational moduli at the interface, both suggested that the adsorbed protein film consists primarily of GHs rather than of EW proteins. Nonetheless, FS was higher when EW proteins were present. Mixed GH + EW solutions have a higher resistance to coalescence than GH solutions. Therefore, it is hypothesized that EW proteins form a secondary protein layer below the A-W interface which is maintained by interactions with adsorbed GH constituents, thereby providing bubbles with an additional resistance to coalescence
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