6,222 research outputs found
Coseismic thrusting and folding in the 1999 M_w 7.6 Chi-Chi earthquake: A high-resolution approach by aerial photos taken from Tsaotun, central Taiwan
We used aerial photos taken before and after the 21 September 1999, M_w 7.6, Chi-Chi earthquake in central Taiwan to measure the near-field ground deformation. A total of 12 pairs of images were processed with Co-registration of Optically Sensed Images and Correlation to produce a horizontal displacement map of a 10 km × 10 km area near Tsaotun. Using pairs of images with different viewing angles, both the horizontal and vertical slip across the fault zone can be measured. Our measurements when resampled into lower resolution are consistent with lower resolution measurements of horizontal displacements obtained from SPOT images, as well as with vertical displacements obtained from repeated leveling measurements and field observations. Horizontal strain is strongly localized along the Chelungpu fault (CLPF) and along a secondary scarp that runs parallel to the CLPF about 2 km to the east, the Ailiao fold scarp (ALF). This pattern closely matches the surface ruptures mapped in the field. Horizontal strain across CLPF correlates remarkably well with the topographic features produced by long-term deformation. The cumulative horizontal shortening across the CLPF and ALF amounts to 4.9 ± 0.4 and 6.1 ± 0.6 m, respectively, and fault-parallel displacement is 3.4 ± 0.4 m. The pattern of surface strain is consistent with the interpretation of the ALF as a fold scarp formed over an active axial hinge zone. This study shows that, even in this compressional setting, most surface deformation is localized within narrow fault zones or active axial hinges
Self-Assembly of a Virus-Mimicking Nanostructure System for Efficient Tumor-Targeted Gene Delivery
This is the published version, also available here: http://dx.doi.org/10.1089/10430340252792594.Molecular therapy, including gene therapy, is a promising strategy for the treatment of human disease. However, delivery of molecular therapeutics efficiently and specifically to the target tissue remains a significant challenge. A human transferrin (Tf)-targeted cationic liposome-DNA complex, Tf-lipoplex, has shown high gene transfer efficiency and efficacy with human head and neck cancer in vitro and in vivo (Xu, L., Pirollo, K.F., Tang, W.H., Rait, A., and Chang, E.H. Hum. Gene Ther. 1999;10:2941-2952). Here we explore the structure, size, formation process, and structure-function relationships of Tf-lipoplex. We have observed Tf-lipoplex to have a highly compact structure, with a relatively uniform size of 50-90 nm. This nanostructure is novel in that it resembles a virus particle with a dense core enveloped by a membrane coated with Tf molecules spiking the surface. More importantly, compared with unliganded lipoplex, Tf-lipoplex shows enhanced stability, improved in vivo gene transfer efficiency, and long-term efficacy for systemic p53 gene therapy of human prostate cancer when used in combination with conventional radiotherapy. On the basis of our observations, we propose a multistep self-assembly process and Tf-facilitated DNA cocondensation model that may provide an explanation for the resultant small size and effectiveness of our nanostructural Tf-lipoplex system
Antioxidant synergism between ethanolic Centella asiatica extracts and α-tocopherol in model systems.
The synergistic antioxidant effects of ethanolic extracts of Centella asiatica (CE), and α-tocopherol have been studied. The types of interactions exhibited by CE and α-tocopherol combined at different ratios were measured using three assays: 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) radical-scavenging capacity, the β-carotene bleaching system and liposome peroxidation assays. Fixed-fraction isobolographic analysis was used to detect any inducement of the antioxidant activity compared with the individual activities of CE and α-tocopherol. Of all synergistic combinations of CE and α-tocopherol, only fraction 2/3 showed the synergistic combination that fits well in three different assays and can be explained by the regeneration of α-tocopherol by CE despite the interaction effect of β-carotene present in the analytical assay. This phenomenon involved complex interactions between CE and α-tocopherol to exhibit different degrees of interactions that eventually increased antioxidant activity
Effects of Parton Intrinsic Transverse Momentum on Photon Production in Hard-Scattering Processes
We calculate the photon production cross section arising from the hard
scattering of partons in nucleon-nucleon collisions by taking into account the
intrinsic parton transverse momentum distribution and the next-to-leading-order
contributions. As first pointed out by Owens, the inclusion of the intrinsic
transverse momentum distribution of partons leads to an enhancement of photon
production cross section in the region of photon transverse momenta of a few
GeV/c for nucleon-nucleon collisions at a center-of-mass energy of a few tens
of GeV. The enhancement increases as decreases. Such an enhancement
is an important consideration in the region of photon momenta under
investigation in high-energy heavy-ion collisions.Comment: 10 pages, 9 figures, in LaTex, revised to include ananlytic
evaluation of the hard-scattering integra
Foundations of Ring Sampling
A ring signature scheme allows the signer to sign on behalf of an ad hoc set of users, called a ring. The verifier can be convinced that a ring member signs, but cannot point to the exact signer. Ring signatures have become increasingly important today with their deployment in anonymous cryptocurrencies. Conventionally, it is implicitly assumed that all ring members are equally likely to be the signer. This assumption is generally false in reality, leading to various practical and devastating deanonymizing attacks in Monero, one of the largest anonymous cryptocurrencies. These attacks highlight the unsatisfactory situation that how a ring should be chosen is poorly understood.
We propose an analytical model of ring samplers towards a deeper understanding of them through systematic studies. Our model helps to describe how anonymous a ring sampler is with respect to a given signer distribution as an information-theoretic measure. We show that this measure is robust, in the sense that it only varies slightly when the signer distribution varies slightly. We then analyze three natural samplers -- uniform, mimicking, and partitioning -- under our model with respect to a family of signer distributions modeled after empirical Bitcoin data. We hope that our work paves the way towards researching ring samplers from a theoretical point of view
Electrical conductivity of anhydrous and hydrous gabbroic melt under high temperature and high pressure: implications for the high-conductivity anomalies in the mid-ocean ridge region
The electrical conductivity of gabbroic melt with four different water
contents (i.e., 0 %, 2.59 wt %, 5.92 wt %, and 8.32 wt %) was measured at
temperatures of 873–1373 K and pressures of 1.0–3.0 GPa using a YJ-3000t
multi-anvil high-pressure apparatus and Solartron-1260 impedance
spectroscopy analyzer. At a fixed water content of 2.59 wt %, the
electrical conductivity of the sample slightly decreased with increasing
pressure in the temperature range of 873–1373 K, and its corresponding
activation energy and activation volume were determined as 0.87 ± 0.04 eV and −1.98 ± 0.02 cm3 molec.−1, respectively. Under the
certain conditions of 873–1373 K and 1.0 GPa, the electrical conductivity of
the gabbroic melts tends to gradually increase with a rise in water content
from 0 wt % to 8.32 wt %, and the activation enthalpy decreases from 0.93 to
0.63 eV accordingly. Furthermore, functional relation models for the
electrical conductivity of gabbroic melts with variations of
temperature, pressure, and water content were constructed at high-temperature
and high-pressure conditions. In addition, the dependence
relation of the electrical conductivity of melts with the degree of
depolymerization was explored under conditions of four different water
contents at 1373 K and 1.0 GPa, and three previously available reported
results on those of representative calc-alkaline igneous rock melts (i.e.,
dacitic melt, basaltic melt, and andesitic melt) were compared in detail. In
combination with our presently acquired electrical
conductivity data on gabbroic melt with four different water contents and
the available data on polycrystalline olivine, the electrical conductivity
of a gabbroic melt–olivine system with variation of the volume percentage of
anhydrous and hydrous melts was successfully constructed by using the
typical Hashin–Shtrikman upper-bound model. In light of the electrical
conductivity of the gabbroic melt–olivine system with previous magnetotelluric (MT) results,
we find that anhydrous and hydrous gabbroic melts can be employed to
reasonably interpret the high-conductivity anomalies in the Mohns Ridge of
the Arctic Ocean.</p
Non-adjacent dependency learning in Cantonese-speaking children with and without a history of specific language impairment
Purpose: This study investigated non-adjacent dependency learning in Cantonese-speaking children with and without a history of Specific Language Impairment (SLI) in an artificial linguistic context.
Method: Sixteen Cantonese-speaking children with SLI history and 16 Cantonese-speaking children with typical language development (TLD) were tested with a non-adjacent dependency learning task using artificial languages that mimic Cantonese.
Results: Children with TLD performed above chance and were able to discriminate between trained and untrained non-adjacent dependencies. However, children with SLI
history performed at chance and were not able to differentiate trained versus untrained non-adjacent dependencies.
Conclusions: These findings, together with previous findings with English-speaking adults and adolescents with language impairments, suggested that individuals with atypical language development, regardless of age, diagnostic status, language and culture, showed difficulties in learning non-adjacent dependencies. This study provides evidence for early impairments to statistical learning in individuals with atypical language development
Effects of the R-parity violation in the minimal supersymmetric standard model on dilepton pair production at the CERN LHC
We investigate in detail the effects of the R-parity lepton number violation
in the minimal supersymmetric standard model (MSSM) on the parent process at the CERN Large Hadron Collider (LHC). The numerical
comparisons between the contributions of the R-parity violating effects to the
parent process via the Drell-Yan subprocess and the gluon-gluon fusion are
made. We find that the R-violating effects on pair production at the
LHC could be significant. The results show that the cross section of the pair productions via gluon-gluon collision at the LHC can be of the order
of fb, and this subprocess maybe competitive with the production
mechanism via the Drell-Yan subprocess. We give also quantitatively the
analysis of the effects from both the mass of sneutrino and coupling strength
of the R-parity violating interactions.Comment: 18 pages, 10 figures, accepted by Phys. Rev.
On Defeating Graph Analysis of Anonymous Transactions
In a ring-signature-based anonymous cryptocurrency, signers of a transaction are hidden among a set of potential signers, called a ring, whose size is much smaller than the number of all users. The ring-membership relations specified by the sets of transactions thus induce bipartite transaction graphs, whose distribution is in turn induced by the ring sampler underlying the cryptocurrency.
Since efficient graph analysis could be performed on transaction graphs to potentially deanonymise signers, it is crucial to understand the resistance of (the transaction graphs induced by) a ring sampler against graph analysis. Of particular interest is the class of partitioning ring samplers. Although previous works showed that they provide almost optimal local anonymity, their resistance against global, e.g. graph-based, attacks were unclear.
In this work, we analyse transaction graphs induced by partitioning ring samplers. Specifically, we show (partly analytically and partly empirically) that, somewhat surprisingly, by setting the ring size to be at least logarithmic in the number of users, a graph-analysing adversary is no better than the one that performs random guessing in deanonymisation up to constant factor of 2
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