201 research outputs found

    The Digestive Mechanism of the European Squids Loligo vulgaris, Loligo forbesii, alloteuthis media and Alloteutihis subulata

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    1. The degestive mechanism has been investigated in Loligo forbesii, L.vulgaris, Alloteuthis media, and A. subulata. Histology and morphology were examined on living and fixed material and the feeding of L.vulgaris was observed in the living animal. 2. The food is bitten by the jaws and rapidly swallowed; the radula has no rasing action. 3. Preliminary digestion takes place in the stomach, which is cuticle-lined. 4. The caecum is a complex organ, containing the opening of the mid-gut gland. This opening is connected with the closing mechanism of the caeco-intestinal opening in such a way that the hepato-pancreatic secretion can be directed either to the caecum or to the stomach. The anterior part of the caecum contains a ciliary collecting mechanism whose main groove lads along the intestine towards the anus. 5. The posterior part of the caecum is a simple ciliated sac where digestion is competed, food absorbed, and pancreatic secretion stored between meals. Solid food other than particulate is never found in the caecum. 6. The intestine is a short, straight tube, lined with a ciliated and mucous epithelium. Absorption also takes place here, and continues after the caecum has ceased absorbing. 7. The junction of intestine and rectum is considered to be defined by the, replacement of the ciliated epithelium by one with a hyaline border. 8. The rectum is short; in the region of the rectal sphincter it is lined with cells bearing curious retractile processes, whose possible function is discussed. 9. The mid-gut gland secretes all digestive enzymes; it is divided into two unequal and markedly different glands: the so-called ‘liver’ and ‘pancreas’. These are connected in series, so that hepatic secretion flows through the main lumen of the pancreas to reach the caecum. 10. Hepatic secretion is passed into the caecum only during digestion. The liver has a single type of cell in which food reserves also accumulate. The hepatic duct can be closed by a sphincter. 11. Pancreatic secretion accumulates in the caecum between meals and apparently passes to the stomach during digestion. The structure and rhythm of the cells of the pancreas and the nature of its blood-supply suggest some second activity, possibly directed towards the blood-stream, alternating with that of enzyme-secretion. 12. Food is not absorbed in the mid-gut gland. 13. The structural and functional peculiarities of the digestive system of these squids may be related to an exceptionally speedy and efficient digestive mechanism, well fitted to the life of a perpetually swimming, active predator

    One-Loop NMHV Amplitudes involving Gluinos and Scalars in N=4 Gauge Theory

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    We use Supersymmetric Ward Identities and quadruple cuts to generate n-pt NMHV amplitudes involving gluinos and adjoint scalars from purely gluonic amplitudes. We present a set of factors that can be used to generate one-loop NMHV amplitudes involving gluinos or adjoint scalars in N=4 Super Yang-Mills from the corresponding purely gluonic amplitude.Comment: 16 pages, JHEP versio

    Differential display identifies overexpression of the USP36 gene, encoding a deubiquitinating enzyme, in ovarian cancer

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    Objectives. To find potential diagnostic markers or therapeutic targets, we used differential display technique to identify genes that are over or under expressed in human ovarian cancer. Methods. Genes were initially identified by differential display between two human ovarian surface epithelium cultures and two ovarian cancer cell lines, A2780 and Caov-3. Genes were validated by relative quantitative RT-PCR and RNA in situ hybridization. Results. Twenty-eight non-redundant sequences were expressed differentially in the normal ovarian epithelium and ovarian cancer cell lines. Seven of the 28 sequences showed differential expression between normal ovary and ovarian cancer tissue by RT-PCR. USP36 was over-expressed in ovarian cancer cell lines and tissues by RT-PCR and RNA in situ hybridization. Northern blot analysis and RT-PCR revealed two transcripts for USP36 in ovarian tissue. The major transcript was more specific for ovarian cancer and was detected by RT-PCR in 9/9 ovarian cancer tissues, 3/3 cancerous ascites, 5/14 (36%) sera from patients with ovarian cancer, and 0/7 sera from women without ovarian cancer. Conclusion. USP36 is overexpressed in ovarian cancer compared to normal ovary and its transcripts were identified in ascites and serum of ovarian cancer patients

    Ancient Roman coin retrieval : a systematic examination of the effects of coin grade

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    Ancient coins are historical artefacts of great significance which attract the interest of scholars, and a large and growing number of amateur collectors. Computer vision based analysis and retrieval of ancient coins holds much promise in this realm, and has been the subject of an increasing amount of research. The present work is in great part motivated by the lack of systematic evaluation of the existing methods in the context of coin grade which is one of the key challenges both to humans and automatic methods. We describe a series of methods – some being adopted from previous work and others as extensions thereof – and perform the first thorough analysis to date.Postprin

    SUSY Ward identities for multi-gluon helicity amplitudes with massive quarks

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    We use supersymmetric Ward identities to relate multi-gluon helicity amplitudes involving a pair of massive quarks to amplitudes with massive scalars. This allows to use the recent results for scalar amplitudes with an arbitrary number of gluons obtained by on-shell recursion relations to obtain scattering amplitudes involving top quarks.Comment: 22 pages, references adde

    The No-Triangle Hypothesis for N=8 Supergravity

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    We study the perturbative expansion of N=8 supergravity in four dimensions from the viewpoint of the ``no-triangle'' hypothesis, which states that one-loop graviton amplitudes in N=8 supergravity only contain scalar box integral functions. Our computations constitute a direct proof at six-points and support the no-triangle conjecture for seven-point amplitudes and beyond.Comment: 43page

    Prying into the intimate secrets of animal lives; software beyond hardware for comprehensive annotation in ‘Daily Diary’ tags

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    Smart tags attached to freely-roaming animals recording multiple parameters at infra-second rates are becoming commonplace, and are transforming our understanding of the way wild animals operate. However, interpretation of such data is complex and currently limits the ability of biologists to realise the value of their recorded information. This work presents a single program, FRAMEWORK 4, that uses a particular sensor constellation described in the?Daily Diary? tag (recording tri-axial acceleration, tri-axial magnetic field intensity, pressure and e.g. temperature and light intensity) to determine the 4 key elements considered pivotal within the conception of the tag. These are; animal trajectory, behaviour, energy expenditure and quantification of the environment in which the animal operates. The program takes the original data recorded by the Daily Dairy and transforms it into dead-reckoned movements,template-matched behaviours, dynamic body acceleration-derived energetics and positionlinked environmental data before outputting it all into a single file. Biologists are thus left with a single data set where animal actions and environmental conditions can be linked across time and space.Fil: Walker, James S.. Swansea University. College Of Sciences; Reino UnidoFil: Jones, Mark W.. Swansea University. College Of Sciences; Reino UnidoFil: Laramee, Robert S.. Swansea University. College Of Sciences; Reino UnidoFil: Holton, Mark D.. Swansea University; Reino UnidoFil: Shepard, Emily L. C.. Swansea University. College Of Sciences; Reino UnidoFil: Williams, Hannah J.. Swansea University. College Of Sciences; Reino UnidoFil: Scantlebury, D. Michael. The Queens University Of Belfast; IrlandaFil: Marks, Nikki, J.. The Queens University Of Belfast; IrlandaFil: Magowan, Elizabeth A.. The Queens University Of Belfast; IrlandaFil: Maguire, Iain E.. The Queens University Of Belfast; IrlandaFil: Grundy, Ed. Swansea University. College Of Sciences; Reino UnidoFil: Di Virgilio, Agustina Soledad. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Patagonia Norte. Instituto de InvestigaciĂłn En Biodiversidad y Medioambiente; Argentina. Universidad Nacional del Comahue; ArgentinaFil: Wilson, Rory P.. Swansea University. College Of Sciences; Reino Unid

    MHV-Vertices for Gravity Amplitudes

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    We obtain a CSW-style formalism for calculating graviton scattering amplitudes and prove its validity through the use of a special type of BCFW-like parameter shift. The procedure is illustrated with explicit examples.Comment: 21 pages, minor typos corrected, proof added in section

    Orbifolding the Twistor String

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    The D-instanton expansion of the topological B-model on the supermanifold CP(3|4) reproduces the perturbative expansion of N=4 Super Yang-Mills theory. In this paper we consider orbifolds in the fermionic directions of CP(3|4). This operation breaks the SU(4) R-symmetry group, reducing the amount of supersymmetry of the gauge theory. As specific examples we take N=1 and N=2 orbifolds and obtain the corresponding superconformal quiver theories. We discuss the D1 instanton expansion in this context and explicitly compute some amplitudes.Comment: 24 pages, 8 figures; v2: minor correction

    Proof of the MHV vertex expansion for all tree amplitudes in N=4 SYM theory

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    We prove the MHV vertex expansion for all tree amplitudes of N=4 SYM theory. The proof uses a shift acting on all external momenta, and we show that every N^kMHV tree amplitude falls off as 1/z^k, or faster, for large z under this shift. The MHV vertex expansion allows us to derive compact and efficient generating functions for all N^kMHV tree amplitudes of the theory. We also derive an improved form of the anti-NMHV generating function. The proof leads to a curious set of sum rules for the diagrams of the MHV vertex expansion.Comment: 40 pages, 7 figure
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