5,240 research outputs found
XML Security in Certificate Management - XML Certificator
The trend of rapid growing use of XML format in data/document management system reveals that security measures should be urgently considered into next generation's data/document systems. This paper presents a new certificate management system developed on the basis of XML security mechanisms. The system is supported by the theories of XML security as well as Object oriented technology and database. Finally it has been successfully implemented in using C&#, SQL, XML signature and XML encryption. An implementation metrics is evidently presented
Hydrogen Peroxide Wound Irrigation in Orthopaedic Surgery.
As the burden of deep hardware infections continues to rise in orthopaedics, there is increasing interest in strategies for more effective debridement of colonized tissues and biofilm. Hydrogen peroxide has been used medically for almost a century, but its applications in orthopaedic surgery have yet to be fully determined. The basic science and clinical research on the antiseptic efficacy of hydrogen peroxide have demonstrated its efficacy against bacteria, and it has demonstrated potential synergy with other irrigation solutions such as chlorhexidine and povidone-iodine. While hydrogen peroxide is effective in infection reduction, there are concerns with wound healing, cytotoxicity, and embolic phenomena, and we recommend against hydrogen peroxide usage in the treatment of partial knee replacements, hemiarthroplasties, or native joints. Additionally, due to the potential for oxygen gas formation, hydrogen peroxide should not be used in cases of dural compromise, when pressurizing medullary canals, or when irrigating smaller closed spaces to avoid the possibility of air embolism. Finally, we present our protocol for irrigation and debridement and exchange of modular components in total joint arthroplasty, incorporating hydrogen peroxide in combination with povidone-iodine and chlorhexidine
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Two key events associated with a transposable element burst occurred during rice domestication
Transposable elements shape genome evolution through periodic bursts of amplification. In this study we exploited knowledge of the components of the mPing/Ping/Pong TE family in four rice strains undergoing mPing bursts to track their copy numbers and distribution in a large collection of genomes from the wild progenitor Oryza rufipogon and domesticated Oryza sativa (rice). We characterized two events that occurred to the autonomous Ping element and appear to be critical for mPing hyperactivity. First, a point mutation near the end of the element created a Ping variant ( Ping16A ) with reduced transposition. The proportion of strains with Ping16A has increased during domestication while the original Ping (Ping16G) has been dramatically reduced. Second, transposition of Ping16A into a Stowaway element generated a locus ( Ping16A_Stow ) whose presence correlates with strains that have high mPing copies. Finally, demonstration that Pong elements have been stably silenced in all strains analyzed indicates that sustained activity of the mPing/Ping family during domestication produced the components necessary for the mPing burst, not the loss of epigenetic regulation
The quest for organo-alkali metal monomers: unscrambling the structure–reactivity relationship
Organo-alkali metal reagents are essential tools in synthetic chemistry. Alkali metal organometallics aggregate in solution and solid-state forming clusters and polymers. The structure of these aggregates and their structure–reactivity relationship have been of great interest for many decades. This Perspective will look at the strategies that have been employed to isolate low aggregates and, in particular, monomeric complexes of the most common alkali metal alkyls (M = Li–Cs, R = methyl, trimethylsilylmethyl, bis/tris(trimethylsilylmethyl), butyls and benzyl) and the relationship between level of aggregation, structure and reactivity
A W-String Realization of the Bosonic String
It has recently been shown that the ordinary bosonic string can be
represented by a special background of N=1 or N=2 strings. In this paper, it
will be shown that the bosonic string can also be represented by a special
background of -strings.Comment: 8 pages plain Tex, KCL-TH-93-1
Patent Citation Dynamics Modeling via Multi-Attention Recurrent Networks
Modeling and forecasting forward citations to a patent is a central task for
the discovery of emerging technologies and for measuring the pulse of inventive
progress. Conventional methods for forecasting these forward citations cast the
problem as analysis of temporal point processes which rely on the conditional
intensity of previously received citations. Recent approaches model the
conditional intensity as a chain of recurrent neural networks to capture memory
dependency in hopes of reducing the restrictions of the parametric form of the
intensity function. For the problem of patent citations, we observe that
forecasting a patent's chain of citations benefits from not only the patent's
history itself but also from the historical citations of assignees and
inventors associated with that patent. In this paper, we propose a
sequence-to-sequence model which employs an attention-of-attention mechanism to
capture the dependencies of these multiple time sequences. Furthermore, the
proposed model is able to forecast both the timestamp and the category of a
patent's next citation. Extensive experiments on a large patent citation
dataset collected from USPTO demonstrate that the proposed model outperforms
state-of-the-art models at forward citation forecasting
Inherent Negative Refraction on Acoustic Branch of Two Dimensional Phononic Crystals
Guided by theoretical predictions, we have demonstrated experimentally the
existence of negative refraction on the lowest two (acoustic) passbands (shear
and longitudinal modes) of a simple two dimensional phononic crystal consisting
of an isotropic stiff (aluminum) matrix and square- patterned isotropic
compliant (PMMA) circular inclusions. At frequencies and wave vectors where the
refraction is negative, the effective mass density and the effective stiffness
tensors of the crystal can be positive-defnite, and that, this is an inherent
property of phononic crystals with an isotropic stiff matrix containing
periodically distributed isotropic compliant inclusions. The equi-frequency
contours and energy ux vectors as fuctions of the phase-vector components,
reveal a rich body of refractive properties that can be exploited to realize,
for example, beam splitting, focusing, and frequency filtration on the lowest
passbands of the crystal where the dissipation is the least. By proper
selection of material and geometric parameters these phenomena can be realized
at remarkably low frequencies (large wave lengths) using rather small simple
two-phase unit cells. Keywords: Doubly periodic phononic crystals, acoustic
branch negative refraction, beam splitting, focusing, imaging, frequency
filtration at large wave length
Improved IEEE 802.11 point coordination function considering fiber-delay difference in distributed antenna systems
In this paper, we present an improved IEEE 802.11 wireless local-area network (WLAN) medium access control (MAC) mechanism for simulcast radio-over-fiber-based distributed antenna systems where multiple remote antenna units (RAUs) are connected to one access point (AP). In the improved mechanism, the fiber delay between RAUs and central unit is taken into account in a modification to the conventional point coordination function (PCF) that achieves coordination by a centralized algorithm. Simulation results show that the improved PCF outperforms the distributed coordination function (DCF) in both the basic-access and request/clear-to-send modes in terms of the total throughput and the fairness among RAU
Discovery of low-metallicity stars in the central parsec of the Milky Way
We present a metallicity analysis of 83 late-type giants within the central 1
pc of the Milky Way. K-band spectroscopy of these stars were obtained with the
medium-spectral resolution integral-field spectrograph NIFS on Gemini North
using laser-guide star adaptive optics. Using spectral template fitting with
the MARCS synthetic spectral grid, we find that there is large variation in
metallicity, with stars ranging from [M/H] -1.0 to above solar metallicity.
About 6\% of the stars have [M/H] -0.5. This result is in contrast to
previous observations, with smaller samples, that show stars at the Galactic
center have approximately solar metallicity with only small variations. Our
current measurement uncertainties are dominated by systematics in the model,
especially at [M/H] 0, where there are stellar lines not represented in the
model. However, the conclusion that there are low metallicity stars, as well as
large variations in metallicity is robust. The metallicity may be an indicator
of the origin of these stars. The low-metallicity population is consistent with
that of globular clusters in the Milky Way, but their small fraction likely
means that globular cluster infall is not the dominant mechanism for forming
the Milky Way nuclear star cluster. The majority of stars are at or above solar
metallicity, which suggests they were formed closer to the Galactic center or
from the disk. In addition, our results indicate that it will be important for
star formation history analyses using red giants at the Galactic center to
consider the effect of varying metallicity.Comment: 11 pages, 10 figures, ApJ Accepte
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