152 research outputs found
Spin constraints on Regge predictions and perturbative evolution in high energy collisions
Two key issues in the application of perturbative QCD and Regge predictions
to high energy processes are whether the hard and soft pomerons should be
considered as two separate distinct exchanges and whether the Regge intercepts
are Q^2 independent or not. Models involving a distinct hard pomeron exchange
predict much larger values for the LHC total cross-section. Here we argue that
there is a polarized analogue of this issue in the isovector part of the spin
structure function g_1 and that the spin data appear to favour a distinct hard
exchange.Comment: 8 page
Application of Silicon Carbide Chills in Controlling the Solidification Process of Casts Made of IN-713C Nickel Superalloy
The paper presents the method of manufacturing casts made of the IN-713C nickel superalloy using the wax lost investment castingprocess and silicon carbide chills. The authors designed experimental casts, the gating system and selected the chills material. Wax pattern,ceramic shell mould and experimental casts were prepared for the purposes of research. On the basis of the temperature distributionmeasurements, the kinetics of the solidification process was determined in the thickened part of the plate cast. This allowed to establish thequantity of phase transitions which occurred during cast cooling process and the approximate values of liquidus, eutectic, solidus andsolvus temperatures as well as the solidification time and the average value of cast cooling rate. Non-destructive testing and macroscopicanalysis were applied to determine the location and size of shrinkage defects. The authors present the mechanism of solidification andformation of shrinkage defects in casts with and without chills. It was found that the applied chills influence significantly the hot spots andthe remaining part of the cast. Their presence allows to create conditions for solidification of IN-713C nickel superalloy cast withoutshrinkage defects
Augmented collisional ionization via excited states in XUV cluster interactions
The impact of atomic excited states is investigated via a detailed model of
laser-cluster interactions, which is applied to rare gas clusters in intense
femtosecond pulses in the extreme ultraviolet (XUV). This demonstrates the
potential for a two-step ionization process in laser-cluster interactions, with
the resulting intermediate excited states allowing for the creation of high
charge states and the rapid dissemination of laser pulse energy. The
consequences of this excitation mechanism are demonstrated through simulations
of recent experiments in argon clusters interacting with XUV radiation, in
which this two-step process is shown to play a primary role; this is consistent
with our hypothesis that XUV-cluster interactions provide a unique window into
the role of excited atomic states due to the relative lack of photoionization
and laser field-driven phenomena. Our analysis suggests that atomic excited
states may play an important role in interactions of intense radiation with
materials in a variety of wavelength regimes, including potential implications
for proposed studies of single molecule imaging with intense X-rays.Comment: 4 pages, 2 figure
Intermittency for coherent and incoherent current ensemble model
We investigate the origin of intermittency for multiparticle distribution in
momentum space, following the idea that there is a kind of power law
distribution of the space-time region of hadron emission. Using the formalism
of current ensamble model to describe boson sources we discuss intermittency
exponents for the coherent and incoherent ( chaotic) particle production
scheme.Comment: 13 pages, latex, no figure
Zawartość metalicznych i niemetalicznych pierwiastków w homogenatach próbek tkankowych pobranych z amputowanych na poziomie uda z powodu miażdżycy kończyn dolnych. Doniesienie wstępne
Background: Metallic and non-metallic elements have influence on the development the changes within
structure and function of arteries in different regions of vascular tree. The content of elements into
arterial walls varies according to geographical origin of people.
Material and methods: Tissue specimens were taken from the six lower limbs amputated on the level of
thigh due to atherosclerosis. The mean age was 69 (57 to 84). Tissue specimens were collected from the
limbs from the level of amputation, the popliteal fossa and the dorsal artery of foot. After chemical processing
of the tissues homogenates determination of the content of elements using atomic emission spectrometry
method with inductively coupled plasma (inductively coupled plasma optical emission spectroscopy)
was performed. The content of Al, Ba, Ca, Cu, Fe, K, Mg, Mn, P, S, Sr and Zn was determined.
Results: As a point of reference mean absolute value occurred from six specimens on the level of thigh
was assumed as 100%. Content of non-metallic elements such as Ca, P and S rise towards to periphery
of amputated limb reaching few times higher values on the level of dorsal artery of foot. Content of some
metallic elements such as: Fe, Zn, K and Sr also rise towards to periphery of extremity. The Cu accumulation
was the highest on the level of popliteal fossa, while Mn, Al and Mg concentration was the lowest
on this same level and the highest in dorsal artery of foot.
Conclusions: The influence of individual elements on development the atherosclerosis especially on
necrotic changes requires further investigations.
Described problem pose a preliminary report only in order to indicate the issue and to check the method
of analysis
TESLA Technical Design Report Part III: Physics at an e+e- Linear Collider
The TESLA Technical Design Report Part III: Physics at an e+e- Linear
ColliderComment: 192 pages, 131 figures. Some figures have reduced quality. Full
quality figures can be obtained from http://tesla.desy.de/tdr. Editors -
R.-D. Heuer, D.J. Miller, F. Richard, P.M. Zerwa
Bragg coherent diffraction imaging and metrics for radiation damage in protein micro-crystallography
The proliferation of extremely intense synchrotron sources has enabled ever higher-resolution structures to be obtained using data collected from smaller and often more imperfect biological crystals (Helliwell, 1984). Synchrotron beamlines now exist that are capable of measuring data from single crystals that are just a few micrometres in size. This provides renewed motivation to study and understand the radiation damage behaviour of small protein crystals. Reciprocal-space mapping and Bragg coherent diffractive imaging experiments have been performed on cryo-cooled microcrystals of hen egg-white lysozyme as they undergo radiation damage. Several well established metrics, such as intensity-loss and lattice expansion, are applied to the diffraction data and the results are compared with several new metrics that can be extracted from the coherent imaging experiments. Individually some of these metrics are inconclusive. However, combining metrics, the results suggest that radiation damage behaviour in protein micro-crystals differs from that of larger protein crystals and may allow them to continue to diffract for longer. A possible mechanism to account for these observations is proposed
Novel Arenavirus Sequences in Hylomyscus sp. and Mus (Nannomys) setulosus from Côte d'Ivoire: Implications for Evolution of Arenaviruses in Africa
This study aimed to identify new arenaviruses and gather insights in the evolution of arenaviruses in Africa. During 2003 through 2005, 1,228 small mammals representing 14 different genera were trapped in 9 villages in south, east, and middle west of Côte d'Ivoire. Specimens were screened by pan-Old World arenavirus RT-PCRs targeting S and L RNA segments as well as immunofluorescence assay. Sequences of two novel tentative species of the family Arenaviridae, Menekre and Gbagroube virus, were detected in Hylomyscus sp. and Mus (Nannomys) setulosus, respectively. Arenavirus infection of Mus (Nannomys) setulosus was also demonstrated by serological testing. Lassa virus was not found, although 60% of the captured animals were Mastomys natalensis. Complete S RNA and partial L RNA sequences of the novel viruses were recovered from the rodent specimens and subjected to phylogenetic analysis. Gbagroube virus is a closely related sister taxon of Lassa virus, while Menekre virus clusters with the Ippy/Mobala/Mopeia virus complex. Reconstruction of possible virus–host co-phylogeny scenarios suggests that, within the African continent, signatures of co-evolution might have been obliterated by multiple host-switching events
Flexible barrier materials for protection against electromagnetic fields and their characterization
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