1,978 research outputs found
Malignant Fibrous Histiocytoma of The Pancreas
A case of fibrous histiocytoma of low grade malignancy arising from the uncinate lobe of the pancreas is
reported. This is an unusual site for these extremely rare tumours. Survival up to 4 years has been achieved
in our patient following surgical resection
Capital structure and its determinants in the United Kingdom – a decompositional analysis
Prior research on capital structure by Rajan and Zingales (1995) suggests that the level of gearing in UK companies is positively related to size and tangibility, and negatively correlated with profitability and the level of growth opportunities. However, as argued by Harris and Raviv (1991), 'The interpretation of results must be tempered by an awareness of the difficulties involved in measuring both leverage and the explanatory variables of interest'. In this study the focus is on the difficulties of measuring gearing, and the sensitivity of Rajan and Zingales' results to variations in gearing measures are tested. Based on an analysis of the capital structure of 822 UK companies, Rajan and Zingales' results are found to be highly definitional-dependent. The determinants of gearing appear to vary significantly, depending upon which component of debt is being analysed. In particular, significant differences are found in the determinants of long- and short-term forms of debt. Given that trade credit and equivalent, on average, accounts for more than 62% of total debt, the results are particularly sensitive to whether such debt is included in the gearing measure. It is argued, therefore, that analysis of capital structure is incomplete without a detailed examination of all forms of corporate debt
Abelian functions associated with a cyclic tetragonal curve of genus six
We develop the theory of Abelian functions defined using a tetragonal curve of genus six, discussing in detail the cyclic curve y^4 = x^5 + λ[4]x^4 + λ[3]x^3 + λ[2]x^2 + λ[1]x + λ[0]. We construct Abelian functions using the multivariate sigma-function associated with the curve, generalizing the theory of theWeierstrass℘-function.
We demonstrate that such functions can give a solution to the KP-equation, outlining how a general class of solutions could be generated using a wider class of curves. We also present the associated partial differential equations
satisfied by the functions, the solution of the Jacobi inversion problem, a power series expansion for σ(u) and a new addition formula
Interfacing GHz-bandwidth heralded single photons with a room-temperature Raman quantum memory
Photonics is a promising platform for quantum technologies. However, photon
sources and two-photon gates currently only operate probabilistically.
Large-scale photonic processing will therefore be impossible without a
multiplexing strategy to actively select successful events. High
time-bandwidth-product quantum memories - devices that store and retrieve
single photons on-demand - provide an efficient remedy via active
synchronisation. Here we interface a GHz-bandwidth heralded single-photon
source and a room-temperature Raman memory with a time-bandwidth product
exceeding 1000. We store heralded single photons and observe a clear influence
of the input photon statistics on the retrieved light, which agrees with our
theoretical model. The preservation of the stored field's statistics is limited
by four-wave-mixing noise, which we identify as the key remaining challenge in
the development of practical memories for scalable photonic information
processing
Going places
Journeys. We all make them. Often they take us to exotic places. Sometimes they take us even further. They might take us through time. Or they might take us into a new way of life. There are times too, when we go all over the world and back again only to find that home is, after all, where it’s all happening.
This book contains stories about many different types of journey. We hope you will enjoy travelling into it and finding a world that suits you
Characterization of the material response in the granular ratcheting
The existence of a very special ratcheting regime has recently been reported
in a granular packing subjected to cyclic loading \cite{alonso04}. In this
state, the system accumulates a small permanent deformation after each cycle.
After a short transient regime, the value of this permanent strain accumulation
becomes independent on the number of cycles. We show that a characterization of
the material response in this peculiar state is possible in terms of three
simple macroscopic variables. They are defined that, they can be easily
measured both in the experiments and in the simulations. We have carried out a
thorough investigation of the micro- and macro-mechanical factors affecting
these variables, by means of Molecular Dynamics simulations of a polydisperse
disk packing, as a simple model system for granular material. Biaxial test
boundary conditions with a periodically cycling load were implemented. The
effect on the plastic response of the confining pressure, the deviatoric stress
and the number of cycles has been investigated. The stiffness of the contacts
and friction has been shown to play an important role in the overall response
of the system. Specially elucidating is the influence of the particular
hysteretical behavior in the stress-strain space on the accumulation of
permanent strain and the energy dissipation.Comment: 13 pages, 20 figures. Submitted to PR
33rd New England Intercollegiate Geological Conference: October 8, 9 and 10, 1937, New York City
Excursion A-2: A Geological Traverse from the Hudson River to Long Island Sound; Excursion B-3: Paleontological Trip to the New Jersey Coastal Plain; Excursion C-1: Progressive Metamorphism of the Hudson River Series; Excursion C-2: Glacial Geology of Long Island; Excursion C-3: Engineering Projects in New York City
Enhancing multiphoton rates with quantum memories
Single photons are a vital resource for optical quantum information
processing. Efficient and deterministic single photon sources do not yet exist,
however. To date, experimental demonstrations of quantum processing primitives
have been implemented using non-deterministic sources combined with heralding
and/or postselection. Unfortunately, even for eight photons, the data rates are
already so low as to make most experiments impracticable. It is well known that
quantum memories, capable of storing photons until they are needed, are a
potential solution to this `scaling catastrophe'. Here, we analyze in detail
the benefits of quantum memories for producing multiphoton states, showing how
the production rates can be enhanced by many orders of magnitude. We identify
the quantity as the most important figure of merit in this connection,
where and are the efficiency and time-bandwidth product of the
memories, respectively.Comment: Just over 4 pages, 2 figure
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