3,193 research outputs found
A Similarity Measure for GPU Kernel Subgraph Matching
Accelerator architectures specialize in executing SIMD (single instruction,
multiple data) in lockstep. Because the majority of CUDA applications are
parallelized loops, control flow information can provide an in-depth
characterization of a kernel. CUDAflow is a tool that statically separates CUDA
binaries into basic block regions and dynamically measures instruction and
basic block frequencies. CUDAflow captures this information in a control flow
graph (CFG) and performs subgraph matching across various kernel's CFGs to gain
insights to an application's resource requirements, based on the shape and
traversal of the graph, instruction operations executed and registers
allocated, among other information. The utility of CUDAflow is demonstrated
with SHOC and Rodinia application case studies on a variety of GPU
architectures, revealing novel thread divergence characteristics that
facilitates end users, autotuners and compilers in generating high performing
code
Serum levels and removal by haemodialysis and haemodiafiltration of tryptophan-derived uremic toxins in ESKD patients
Tryptophan is an essential dietary amino acid that originates uremic toxins that contribute to end-stage kidney disease (ESKD) patient outcomes. We evaluated serum levels and removal during haemodialysis and haemodiafiltration of tryptophan and tryptophan-derived uremic toxins, indoxyl sulfate (IS) and indole acetic acid (IAA), in ESKD patients in different dialysis treatment settings. This prospective multicentre study in four European dialysis centres enrolled 78 patients with ESKD. Blood and spent dialysate samples obtained during dialysis were analysed with high-performance liquid chromatography to assess uremic solutes, their reduction ratio (RR) and total removed solute (TRS). Mean free serum tryptophan and IS concentrations increased, and concentration of IAA decreased over pre-dialysis levels (67%, 49%, -0.8%, respectively) during the first hour of dialysis. While mean serum total urea, IS and IAA concentrations decreased during dialysis (-72%, -39%, -43%, respectively), serum tryptophan levels increased, resulting in negative RR (-8%) towards the end of the dialysis session (p < 0.001), despite remarkable Trp losses in dialysate. RR and TRS values based on serum (total, free) and dialysate solute concentrations were lower for conventional low-flux dialysis (p < 0.001). High-efficiency haemodiafiltration resulted in 80% higher Trp losses than conventional low-flux dialysis, despite similar neutral Trp RR values. In conclusion, serum Trp concentrations and RR behave differently from uremic solutes IS, IAA and urea and Trp RR did not reflect dialysis Trp losses. Conventional low-flux dialysis may not adequately clear Trp-related uremic toxins while high efficiency haemodiafiltration increased Trp losses
Second Hopf map and supersymmetric mechanics with Yang monopole
We propose to use the second Hopf map for the reduction (via SU(2) group
action) of the eight-dimensional N=8 supersymmetric mechanics to
five-dimensional supersymmetric systems specified by the presence of an SU(2)
Yang monopole. For our purpose we develop the relevant Lagrangian reduction
procedure. The reduced system is characterized by its invariance under the N=5
or N=4 supersymmetry generators (with or without an additional conserved BRST
charge operator) which commute with the su(2) generators.Comment: Final version. To appear in Phys. Rev.
Signals of Unconventional E Models at Colliders
Generation dependent discrete symmetries often appear in models derived from
superstring theories. In particular, in the framework of E models the
presence of such symmetries is required in order to allow for the radiative
generation of naturally small neutrino masses. Recently it was shown that by
imposing suitable generation dependent discrete symmetries, a class of models
can be consistently constructed in which the three sets of known fermions in
each generation do not have the same assignments with respect to the {\bf 27}
representation of E. In this scenario, the different embedding in the gauge
group of the three generations implies in particular that the known charged
leptons couple in a non--universal way to the new neutral gauge bosons
present in these models. We exploit this fact to study the
signature of this class of models at present and future colliders. We
show that some signals of deviation from lepton universality as well as some
other discrepancies with the standard model predictions which have been
observed at the TRISTAN collider in the production rate of and ,
can be accounted for if the mass is not much heavier than 300 GeV. We
also study the discovery limits for lepton universality violation of this type
at LEP-2 and at the 500 GeV Next Linear Collider (NLC). We show that
models predicting unconventional assignments for the leptons will give an
unmistakable signature, when the mass is as heavy as GeV
(LEP-2) and TeV (NLC).Comment: Plain Tex, 20 pages. 4 PostScript figures (uses `epsf.tex'). Modified
file-format. No changes in the tex
A Spectroscopic Study of a Large Sample of Wolf-Rayet Galaxies
We analyze long-slit spectral observations of 39 Wolf-Rayet (WR) galaxies
with heavy element mass fraction ranging over 2 orders of magnitude, from
Zsun/50 to 2Zsun. Nearly all galaxies in our sample show broad WR emission in
the blue region of the spectrum (the blue bump) consisting of an unresolved
blend of N III 4640, C III 4650, C IV 4658 and He II 4686 emission lines. Broad
C IV 5808 emission (the red bump) is detected in 30 galaxies. Additionally,
weaker WR emission lines are identified, most often the N III 4512 and Si III
4565 lines, which have very rarely or never been seen and discussed before in
WR galaxies. These emission features are characteristic of WN7-WN8 and WN9-WN11
stars respectively.
We derive the numbers of early WC (WCE) and late WN (WNL) stars from the
luminosities of the red and blue bumps, and the number of O stars from the
luminosity of the Hbeta emission line. Additionally, we propose a new technique
for deriving the numbers of WNL stars from the N III 4512 and Si III 4565
emission lines. This technique is potentially more precise than the blue bump
method because it does not suffer from contamination of WCE and early WN (WNE)
stars and nebular gaseous emission.
The N(WR)/N(O+WR) ratio decreases with decreasing metallicity, in agreement
with predictions of evolutionary synthesis models. The N(WC)/N(WN) ratios and
the equivalent widths of the blue bump EW(4650) and of the red bump EW(5808)
derived from observations are also in satisfactory agreement with theoretical
predictions.Comment: 49 pages, 9 figures, to appear in Astrophys.
Ground-State of Charged Bosons Confined in a Harmonic Trap
We study a system composed of N identical charged bosons confined in a
harmonic trap. Upper and lower energy bounds are given. It is shown in the
large N limit that the ground-state energy is determined within an accuracy of
and that the mean field theory provides a reasonable result with
relative error of less than 16% for the binding energy .Comment: 15 page
Building an endangered language resource in the classroom: Universal dependencies for Kakataibo
In this paper, we launch a new Universal Dependencies treebank for an endangered language from Amazonia: Kakataibo, a Panoan language spoken in Peru. We first discuss the collaborative methodology implemented, which proved effective to create a treebank in the context of a Computational Linguistic course for undergraduates. Then, we describe the general details of the treebank and the language-specific considerations implemented for the proposed annotation. We finally conduct some experiments on part-of-speech tagging and syntactic dependency parsing. We focus on monolingual and transfer learning settings, where we study the impact of a Shipibo-Konibo treebank, another Panoan language resourc
The IGEX experiment revisited: a response to the critique of Klapdor-Kleingrothaus,Dietz, and Krivosheina
This paper is a response to the article "Critical View to" the IGEX
neutrinoless double-beta decay experiment..."published in Phys. Rev.D, Volume
65 (2002) 092007," by H.V.Klapdor-Kleingrothaus, A. Dietz, and I.V.Krivosheina,
published as preprint hep-ph/0403056. The criticisms are confronted, and the
questions raised are answered. We demonstrate that the lower limit quoted by
IGEX, for the half life of Ge-76 neutrinoless double beta decay, 1.57x10**25 y,
is correct and that there was no "arithmetical error"-as claimed in the "
Critical Review" article
Unconventional superstring derived E models and neutrino phenomenology
Conventional superstring derived E models can accommodate small neutrino
masses if a discrete symmetry is imposed which forbids tree level Dirac
neutrino masses but allows for radiative mass generation. Since the only
possible symmetries of this kind are known to be generation dependent, we
explore the possibility that the three sets of light states in each generation
do not have the same assignments with respect to the 27 of , leading to
non universal gauge interactions under the additional factors for the
known fermions. We argue that models realising such a scenario are viable, with
their structure being constrained mainly by the requirement of the absence of
flavor changing neutral currents in the Higgs sector. Moreover, in contrast to
the standard case, rank 6 models are not disfavoured with respect to rank 5. By
requiring the number of light neutral states to be minimal, these models have
an almost unique pattern of neutrino masses and mixings. We construct a model
based on the unconventional assignment scenario in which (with a natural choice
of the parameters) m_{\nut}\sim O(10)eV is generated at one loop, m_{\num}
is generated at two loops and lies in a range interesting for the solar
neutrino problem, and \nue remains massless. In addition, since baryon and
lepton number are conserved, there is no proton decay in the model. To
illustrate the non-standard phenomenology implied by our scheme we also discuss
a second scenario in which an attempt for solving the solar neutrino puzzle
with matter enhanced oscillations and practically massless neutrinos can be
formulated, and in which peculiar effects for the \num --> \nut conversion
of the upward-going atmospheric neutrinos could arise as well.Comment: Plain Tex, 33 pages, 3 PostScript figures (uses epsf.tex). Modified
file-format. No changes in the tex
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