315 research outputs found

    On the Impossibility of General Parallel Fast-Forwarding of Hamiltonian Simulation

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    Hamiltonian simulation is one of the most important problems in the field of quantum computing. There have been extended efforts on designing algorithms for faster simulation, and the evolution time T for the simulation greatly affect algorithm runtime as expected. While there are some specific types of Hamiltonians that can be fast-forwarded, i.e., simulated within time o(T), for some large classes of Hamiltonians (e.g., all local/sparse Hamiltonians), existing simulation algorithms require running time at least linear in the evolution time T. On the other hand, while there exist lower bounds of ?(T) circuit size for some large classes of Hamiltonian, these lower bounds do not rule out the possibilities of Hamiltonian simulation with large but "low-depth" circuits by running things in parallel. As a result, physical systems with system size scaling with T can potentially do a fast-forwarding simulation. Therefore, it is intriguing whether we can achieve fast Hamiltonian simulation with the power of parallelism. In this work, we give a negative result for the above open problem in various settings. In the oracle model, we prove that there are time-independent sparse Hamiltonians that cannot be simulated via an oracle circuit of depth o(T). In the plain model, relying on the random oracle heuristic, we show that there exist time-independent local Hamiltonians and time-dependent geometrically local Hamiltonians on n qubits that cannot be simulated via an oracle circuit of depth o(T/n^c), where the Hamiltonians act on n qubits, and c is a constant. Lastly, we generalize the above results and show that any simulators that are geometrically local Hamiltonians cannot do the simulation much faster than parallel quantum algorithms

    Miniature RT–PCR system for diagnosis of RNA-based viruses

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    This paper presents an innovative portable chip-based RT–PCR system for amplification of specific nucleic acid and detection of RNA-based viruses. The miniature RT–PCR chip is fabricated using MEMS (Micro-electro-mechanical-system) techniques, and comprises a micro temperature control module and a PDMS (polydimethylsiloxane)-based microfluidic control module. The heating and sensing elements of temperature control module are both made of platinum and are located within the reaction chambers in order to generate a rapid and uniform thermal cycling. The microfluidic control module is capable of automating testing process with minimum human intervention. In this paper, the proposed miniature RT–PCR system is used to amplify and detect two RNA-based viruses, namely dengue virus type-2 and enterovirus 71 (EV 71). The experimental data confirm the ability of the system to perform a two-step RT–PCR process. The developed miniature system provides a crucial tool for the diagnosis of RNA-based viruses

    Anatomical Asymmetry in Goiter: A Demonstration by Three-dimensional Power Doppler Ultrasound

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    The aim of the present study was to examine the anatomical differences in volumetric and intraparenchymal vascular parameters between the two thyroid lobes of patients with goiter, using three-dimensional power Doppler ultrasound. A total of 89 outpatients with goiter, including 55 with autoimmune thyroid disease (ATD) and 34 with simple goiter (SG), were evaluated by three-dimensional power Doppler ultrasound. Volumetric and intraparenchymal vascular indices including vascularization index, flow index and vascular flow index of each lobe were measured using the Virtual Organ Computer-Aided Analysis system. In all patients with goiter, the volume and vascular indices (vascularization index, flow index and vascular flow index) of the right thyroid lobe were significantly greater than those of the left lobe (p < 0.05). Differences in vascular indices were present in SG but not in ATD. ATD was associated with a larger thyroid volume and higher vascular indices compared with those of SG (p < 0.001), but there were no significant differences in volumetry and vascular indices between euthyroid ATD and SG. In conclusion, the right thyroid lobe was found to be significantly larger and more vascular than the left lobe in subjects with goiter, as measured by three-dimensional power Doppler ultrasound. In addition, ATD was associated with a higher thyroid volume and vascular indices compared with those of SG

    Group Signatures and Accountable Ring Signatures from Isogeny-based Assumptions

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    Group signatures are an important cryptographic primitive providing both anonymity and accountability to signatures. Accountable ring signatures combine features from both ring signatures and group signatures, and can be directly transformed to group signatures. While there exists extensive work on constructing group signatures from various post-quantum assumptions, there has not been any using isogeny-based assumptions. In this work, we propose the first construction of isogeny-based group signatures, which is a direct result of our isogeny-based accountable ring signature. This is also the first construction of accountable ring signatures based on post-quantum assumptions. Our schemes are based on the decisional CSIDH assumption (D-CSIDH) and are proven secure under the random oracle model (ROM)

    PGT-Net: Progressive Guided Multi-task Neural Network for Small-area Wet Fingerprint Denoising and Recognition

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    Fingerprint recognition on mobile devices is an important method for identity verification. However, real fingerprints usually contain sweat and moisture which leads to poor recognition performance. In addition, for rolling out slimmer and thinner phones, technology companies reduce the size of recognition sensors by embedding them with the power button. Therefore, the limited size of fingerprint data also increases the difficulty of recognition. Denoising the small-area wet fingerprint images to clean ones becomes crucial to improve recognition performance. In this paper, we propose an end-to-end trainable progressive guided multi-task neural network (PGT-Net). The PGT-Net includes a shared stage and specific multi-task stages, enabling the network to train binary and non-binary fingerprints sequentially. The binary information is regarded as guidance for output enhancement which is enriched with the ridge and valley details. Moreover, a novel residual scaling mechanism is introduced to stabilize the training process. Experiment results on the FW9395 and FT-lightnoised dataset provided by FocalTech shows that PGT-Net has promising performance on the wet-fingerprint denoising and significantly improves the fingerprint recognition rate (FRR). On the FT-lightnoised dataset, the FRR of fingerprint recognition can be declined from 17.75% to 4.47%. On the FW9395 dataset, the FRR of fingerprint recognition can be declined from 9.45% to 1.09%

    Impact of first-line protease inhibitors on predicted resistance to tipranavir in HIV-1-infected patients with virological failure

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    <p>Abstract</p> <p>Background</p> <p>Tipranavir (TPV) is a recently approved nonpeptidic protease inhibitor (PI) of HIV-1 and has been indicated for those infected with PIs-resistant HIV-1. However, in clinical practice, whether the HIV-1 from the patients with virological failure to the regimens containing first-line PIs remains susceptible to TPV/r may be questionable.</p> <p>Methods</p> <p>To assess the resistance levels to TPV of HIV-1 from patients with treatment failure to first-line PIs, patients who experienced virological failure were tested for genotypic resistance of HIV-1 since August 2006 in National Taiwan University Hospital. Patients were enrolled for this analysis if their failed regimens contained > 12 weeks of atazanavir or lopinavir/ritonavir (defined as ATV group and LPV/r group, respectively), but were excluded if they experienced both or other PIs. The levels of genotypic resistance to TPV/r were determined by TPV mutation score.</p> <p>Results</p> <p>Till May 2008, 21 subjects in ATV group and 20 subjects in LPV/r group were enrolled. The TPV mutation scores in subjects in LPV/r group were significantly higher than these in ATV group (median, 3 vs 1, P = 0.007). 95.2% subjects in ATV group and only 45% subjects in LPV/r group had an estimated maximal virological response to TPV/r (P < 0.001). The resistance levels to TPV/r correlated with the duration of exposure to first-line PIs, whether in ATV or LPV/r group.</p> <p>Conclusion</p> <p>Cross-resistance from first-line PIs may impede the effectiveness of TPV/r-containing salvage therapy. TPV/r should be used cautiously for patients with virological failure to LPV/r especially long duration of exposure.</p

    Sequence variants of the aging gene CISD2 and the risk for Alzheimer's disease

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    Background/PurposeThe CISD2 gene has been related to life span control and mitochondrial dysfunction in animals. In addition, inhibition of mitochondrial enzymes due to an accumulation of beta-amyloid peptide has been related to Alzheimer's disease (AD). This study aimed to explore the association between sequence variants of the CISD2 gene and risk for AD, which has not been explored previously.MethodsThis was a case–control study involving a total of 276 patients with AD who were recruited from three teaching hospitals in Taiwan from 2007 to 2010; 460 controls were recruited from elderly individuals attending for health check-ups and volunteers in the hospital during the same period of time. All participants were aged 60 years or older. Two haplotype-tagging single nucleotide polymorphisms (htSNPs), rs223330 and rs223331, were selected from the CISD2 gene to test the association between their polymorphisms and the risk for dementia, and how ApoE ɛ4 status, sex, hypertension, and type 2 diabetes mellitus might modify this association.Resultsrs223330 variant carriage was not associated with risk for AD [TT versus CC: adjusted odds ratio (AOR) = 0.98, 95% confidence interval (CI) = 0.59–1.62; TC versus CC: AOR = 0.72, 95% CI = 0.47–1.11]. Similar findings were observed for rs223331 (AA versus TT: AOR = 1.12; AT versus TT: AOR = 0.99). In addition, hypertension significantly modified the association between rs223331 and risk for AD (p = 0.005).Three common haplotypes (with a frequency of 99.8%) were observed for CISD2. Common CISD2 haplotypes were not associated with the risk for AD.ConclusionOur findings suggested that CISD2 htSNPs are not associated with AD risk

    The prevalence of ocular diseases in primary and junior high school students on Orchid Island

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    AbstractObjectiveTo assess the prevalence of refractive error and ocular diseases in primary and junior high school students on Orchid Island.Materials and MethodsThis is a cross-sectional study of all students in the primary and junior high schools on Orchid Island conducted within 1 week in 2008. Each student received a visual acuity examination without correction with the Landolt-C chart. An experienced ophthalmologist performed associated assessments through retinoscopy, slit lamp, and fundoscopy.ResultsOf the 403 student residents, 260 were primary school students (139 boys and 121 girls) and 143 were junior high school students (74 boys and 69 girls). Visual acuity in two eyes was < 0.1, in 14 eyes was between 0.1 and 0.3, in 34 eyes was between 0.4 and 0.7, in 225 eyes was between 0.8 and 1.0, and in 531 eyes was between 1.2 and 2.0. Myopia was found in 21 students (21/403, 5.21%; 9 primary school students and 12 junior high school students). Four students (4/403, 0.99%) had amblyopia, of whom two had anisometropia (unilateral high hyperopia), one had high astigmatism in both eyes, and the other had unilateral esotropia. Lens dislocation was found in one student (0.25%) with Marfan syndrome. Retinal vasculitis and optic atrophy were found in one student (0.25%) with systemic lupus erythematosus.ConclusionBecause it is a small, isolated island, Orchid Island still has a unique traditional culture and life style. Therefore the prevalence of myopia in primary school and junior high school students on Orchid Island is low, and 94% of all the students had uncorrected visual acuity above 0.8

    The role of reactive monomer in Pl-free technology for the alignment ability and image sticking performance

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    Polyimide-free technology is a technology in which an additive can replace polyimide film to align LC molecules. In this technology, the additive added in liquid crystal (LC) host can not only affect the alignment behavior, but also affect the reliability of the panel, such as image sticking. Because the polymer is polymerized from the additive in LC, the system of the additive is very important. In this paper, we studied the alignment and image sticking performance fabricated by two different additive systems: 1. the mixed system of additive and reactive monomer; 2. the single additive system. From the results of cell and 28” panel, we can conclude that the mixed system has similar alignment ability and voltage holding ratio to the single additive system, however, has better image sticking performance than the single additive system

    On the (Im)possibility of Time-Lock Puzzles in the Quantum Random Oracle Model

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    Time-lock puzzles wrap a solution s\mathrm{s} inside a puzzle P\mathrm{P} in such a way that ``solving\u27\u27 P\mathrm{P} to find s\mathrm{s} requires significantly more time than generating the pair (s,P)(\mathrm{s},\mathrm{P}), even if the adversary has access to parallel computing; hence it can be thought of as sending a message s\mathrm{s} to the future. It is known [Mahmoody, Moran, Vadhan, Crypto\u2711] that when the source of hardness is only a random oracle, then any puzzle generator with nn queries can be (efficiently) broken by an adversary in O(n)O(n) rounds of queries to the oracle. In this work, we revisit time-lock puzzles in a quantum world by allowing the parties to use quantum computing and, in particular, access the random oracle in quantum superposition. An interesting setting is when the puzzle generator is efficient and classical, while the solver (who might be an entity developed in the future) is quantum powered and is supposed to need a long sequential time to succeed. We prove that in this setting there is no construction of time-lock puzzles solely from quantum (accessible) random oracles. In particular, for any nn-query classical puzzle generator, our attack only asks O(n)O(n) (also classical) queries to the random oracle, even though it does indeed run in quantum polynomial time if the honest puzzle solver needs quantum computing. Assuming perfect completeness, we also show how to make the above attack run in exactly nn rounds while asking a total of mnm\cdot n queries where mm is the query complexity of the puzzle solver. This is indeed tight in the round complexity, as we also prove that a classical puzzle scheme of Mahmoody et al. is also secure against quantum solvers who ask n1n-1 rounds of queries. In fact, even for the fully classical case, our attack quantitatively improves the total queries of the attack of Mahmoody et al. for the case of perfect completeness from Ω(mnlogn)\Omega(mn \log n) to mnmn. Finally, assuming perfect completeness, we present an attack in the ``dual\u27\u27 setting in which the puzzle generator is quantum while the solver is classical. We then ask whether one can extend our classical-query attack to the fully quantum setting, in which both the puzzle generator and the solver could be quantum. We show a barrier for proving such results unconditionally. In particular, we show that if the folklore simulation conjecture, first formally stated by Aaronson and Ambainis [arXiv\u272009] is false, then there is indeed a time-lock puzzle in the quantum random oracle model that cannot be broken by classical adversaries. This result improves the previous barrier of Austrin et. al [Crypto\u2722] about key agreements (that can have interactions in both directions) to time-lock puzzles (that only include unidirectional communication)
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