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The advent of quantum computing threatens blockchain protocols and networks because they utilize non-quantum resistant cryptographic algorithms. When quantum computers become robust enough to run Shor’s algorithm on a large scale, the most used asymmetric algorithms, utilized for digital signatures and message encryption, such as RSA, (EC)DSA, and (EC)DH, will be no longer secure. Quantum computers will be able to break them within a short period of time. Similarly, Grover’s algorithm concedes a quadratic advantage for mining blocks in certain consensus protocols such as proof of work. Today, there are hundreds of billions of dollars denominated in cryptocurrencies and other digital assets that rely on blockchain ledgers as well as thousands of blockchain-based applications storing value in blockchain networks. Cryptocurrencies and blockchain-based applications require solutions that guarantee quantum resistance in order to preserve the integrity of data and assets in these public and immutable ledgers. The quantum threat and some potential solutions are well understood and presented in the literature. However, most proposals are theoretical, require large QKD networks, or propose new quantum-resistant blockchain networks to be built from scratch. Our work, which is presented in this paper, is pioneer in proposing an end-to-end framework for post-quantum blockchain networks that can be applied to existing blockchain to achieve quantum-resistance. We have developed an open-source implementation in an Ethereum-based (i.e., EVM compatible) network that can be extended to other existing blockchains. For the implementation we have (i) used quantum entropy to generate post-quantum key pairs, (ii) established post-quantum TLS connections and X.509 certificates to secure the exchange of information between blockchain nodes over the internet without needing a large QKD network, (iii) introduced a post-quantum second signature in transactions using Falcon-512 post-quantum keys, and (iv) developed the first on-chain verification of post-quantum signatures using three different mechanisms that are compared and analyzed: Solidity smart-contracts run by the validators for each transaction, modified EVM Opcode, and precompiled smart contracts.

Several models have been proposed to build evolution operators to perform quantum walks in a theoretical way, although when wanting to map the resulting evolution operators into quantum circuits to run them in quantum computers, it is often the case that the mapping process is in fact complicated. Nevertheless, when the adjacency matrix of a graph can be decomposed into a sum of permutation matrices, we can always build a shift operator for a quantum walk that has a block diagonal matrix representation. In this paper, we analyze the mapping process of block diagonal operators into quantum circuit form, and apply this method to obtain quantum circuits that generate quantum walks on the most common topologies found in the literature: the straight line, the cyclic graph, the hypercube and the complete graph. The obtained circuits are then executed on quantum processors of the type Falcon r5.11L and Falcon r4T (two of each type) through IBM Quantum Composer platform and on the Qiskit Aer simulator, performing three steps for each topology. The resulting distributions were compared against analytical distributions, using the statistical distance $\ell_1$ as a performance metric. Regarding experimental executions, we obtained short $\ell_1$ distances in the cases of quantum circuits with a low amount of multi-control gates, being the quantum processors of the type Falcon r4T the ones that provided more accurate results., 36 pages

Abstract Automobile transport in megacities poses serious problems in the area of sustainability and environmental security. In the City of Buenos Aires (CABA) it represents 37% of GHG emissions and is an important source of pollutants dangerous to human health. As such, it is an energy consumption sector targeted for the implementation of methods that allow for sustainable urban transport. At the same time, very few previous studies about transport vehicle emissions have utilized the PM10 as an indicator of environmental contamination, considering that the negative impact of this environmental contaminant on human health is widely studied. An emission model linked to an atmospheric dispersion model, statistically validated, were used to study different scenarios of emissions generated by diesel buses. It was observed that in a scenario of zero bus emissions (E0), PM10 immission (air concentrations) concentration in CABA is reduced by half. When studying the energy transition from diesel buses to electric energy, while the rest of the vehicle fleet was maintained at the expense of fossil fuels, the local immission concentration of PM10 in CABA was of the same magnitude of that which was obtained when simulating the (E0) scenario of only private vehicle fleet. This study is relevant in the evaluation of public policy on vehicle emission mitigation that seeks to reduce health risks from poor air quality and to develop a more progressively sustainable city. Article Highlights Transition energy exclusively for buses could reduce PM10 immission values of CABA by 50%. Thermal energy needed to the energy transition does not significant impact the PM10 immission values on the local air quality. Electric buses could reduce the maximum PM10 immission value by half.

Quantum image processing has been developing rapidly in recent years. In this paper, the edge detection algorithm for quantum images is proposed. Three steps are consisted: quantum image smoothing, finding the highlight gradient and quantum edge tracking. In order to implement the above processes, a quantum comparator is designed and quantum circuits for all the steps are given. The proposed quantum edge detection algorithm makes full use of quantum parallelism.

Quantum walks are generalizations of random walks that have extensive applications in various fields including cryptography, quantum algorithms, and quantum networking. Discrete quantum walks can be seen as nonlinear mappings between quantum states and position probability distributions, and this mathematical property may be thought of as an imprint of chaotic behavior and consequently used to generate encryption keys. In this paper, we introduce encryption and decryption algorithms for NEQR images based on discrete quantum walks on a circle. We present full quantum circuits of proposed encryption and decryption algorithms together with digital computer simulations of most common attacks on encrypted images. Our numerical results show that our quantum image encryption and decryption scheme has high efficiency and high security with high large key space.

Quantum image processing (QIMP) is devoted to utilizing the quantum computing technologies to capture, manipulate, and recover quantum images in different formats and for different purposes. Logically, percolating this requires that representations to encode images based on the quantum mechanical composition of any potential quantum computing hardware be conjured. This paper gathers the current mainstream quantum image representations (QIRs) and discusses the advances made in the area. Some similarities, differences, and likely applications for some of the available QIRs are reviewed. We believe this compendium will provide the readership an overview of progress witnessed in the area of QIMP while also simulating further interest to pursue more advanced research in it.

Image segmentation methods based on spectral graph theory, although capable of overcoming some of the drawbacks of the so-called "central"-grouping methods, are computationally expensive and quickly become infeasible to solve as the size of the image grows. As a counter measure, the Nystrom approximation allows to extrapolate the complete grouping solution for these methods using only a proportionally smaller set of samples instead of the whole pixels that compose the image. In this correspondence, we further explore the Nystrom approximation by taking the concept of "regions", pixels of the image previously grouped by a central method, to both reduce the computational resources required and provide a finer segmentation of the image by combining the strengths of both methods. We apply the proposed approach to the segmentation of images of burns where we attempt to extract regions that would roughly correspond to the different degrees of the lesion.

A method for video encryption and decryption on quantum computers is proposed based on color information transformations on each frame encoding the content of the encoding the content of the video. The proposed method provides a flexible operation to encrypt quantum video by means of the quantum measurement in order to enhance the security of the video. To validate the proposed approach, a tetris tile-matching puzzle game video is utilized in the experimental simulations. The results obtained suggest that the proposed method enhances the security and speed of quantum video encryption and decryption, both properties required for secure transmission and sharing of video content in quantum communication.

Utilizing a stockpile of efficient transformations consisting of channel of interest, channel swapping, and quantum Fourier transforms, a duple watermarking strategy on multi-channel quantum images is proposed. It embeds the watermark image both into the spatial domain and the frequency domain of the multi-channel quantum carrier image, while also providing a quantum measurement-based algorithm to generate an unknown key that is used to protect the color information, which accompanies another key that is mainly used to scramble the spatial content of the watermark image in order to further safeguard the copyright of the carrier image. Simulation-based experiments using a watermark logo and nine building images as watermark image and carrier images, respectively, offer a duple protection for the copyright of carrier images in terms of the visible quality of the watermarked images. The proposed stratagem advances available literature in the quantum watermarking research field and sets the stage for the applications aimed at quantum data protection.

In this paper, a novel method of quantum image rotation (QIR) based on shear transformations on NEQR quantum images is proposed. To compute the horizontal and vertical shear mappings required for rotation, we have designed quantum self-adder, quantum control multiplier, and quantum interpolation circuits as the basic computing units in the QIR implementation. Furthermore, we provide several examples of our results by presenting computer simulation experiments of QIR under $$30^\circ $$ , $$45^\circ $$ , and $$60^\circ $$ rotation scenarios and have a discussion onto the anti-aliasing and computational complexity of the proposed QIR method.

Responding to or anticipating a sequence of events caused by adversarial human actors, such as crimes, can be a difficult task. Reinforcement learning has not been highly utilized as a method for positioning agents to respond to such events. In our earlier work, which was applied to positioning naval vessel agents to respond to Somali maritime piracy attacks, we developed a method to synthetically augment the information in the events’ environment with digital pheromones and other information augmenters, used the resulting augmenter signatures as states that agents could react to, and applied reinforcement learning to exploit regularities in the timing and location of events to position agents in spatio-temporal proximity of anticipated events. This work extends that methodology with a new learning boosting method wherein learning is improved as partial augmenter signatures are reinforced, which is not possible when learning is based only on the aggregated state. The enhanced methodology is applied to positioning police patrols in response to a sequence of business robberies in Denver, Colorado and its effectiveness is analyzed.

The capabilities of inductively coupled plasma atomic emission spectrometry (ICP-AES) for the determination of water-soluble vitamins after high-performance liquid chromatography (HPLC) separation have been evaluated for the first time in the present work. Thanks to the multielemental capability of ICP-AES, it has been possible to develop a method for the joint determination of several water-soluble vitamins and minerals. The vitamin chromatograms were obtained by plotting the carbon corrected emission intensity against time. Meanwhile, minerals were determined through the measurement of the emission intensity at their characteristic wavelengths. The established method was applied to the determination of thiamine, riboflavin, pantothenic acid, nicotinamide, ascorbic acid, Cr, Mo, Se, Mn, Zn, Fe, Mg, Ca, and K in multivitamin complexes. Good linearities were obtained, with correlation coefficients above 0.999 for all the vitamins and metals. The detection limits using ICP-AES for vitamins were lower than 10 mg L−1 except for biotin (18 mg L−1) and ascorbic acid (35 mg L−1). Moreover, the limits of detection for metals ranged from 0.3 mg L−1 for K and 0.02 mg L−1 for Mo. Even though the ICP is less sensitive than PDA and MS for vitamin determination, the HPLC-ICP-AES allows determination of vitamins and minerals in a period of time not much higher than that required for the simple determination of the minerals, and it is less sensitive to interferences in trace quantities.

Adiabatic quantum computation (AQC) is a universal model for quantum computation which seeks to transform the initial ground state of a quantum system into a final ground state encoding the answer to a computational problem. AQC initial Hamiltonians conventionally have a uniform superposition as ground state. We diverge from this practice by introducing a simple form of heuristics: the ability to start the quantum evolution with a state which is a guess to the solution of the problem. With this goal in mind, we explain the viability of this approach and the needed modifications to the conventional AQC (CAQC) algorithm. By performing a numerical study on hard-to-satisfy 6 and 7 bit random instances of the satisfiability problem (3-SAT), we show how this heuristic approach is possible and we identify that the performance of the particular algorithm proposed is largely determined by the Hamming distance of the chosen initial guess state with respect to the solution. Besides the possibility of introducing educated guesses as initial states, the new strategy allows for the possibility of restarting a failed adiabatic process from the measured excited state as opposed to restarting from the full superposition of states as in CAQC. The outcome of the measurement can be used as a more refined guess state to restart the adiabatic evolution. This concatenated restart process is another heuristic that the CAQC strategy cannot capture., 13 pages, 5 figures. Quantum Information Processing. In Press

We introduce a novel method for storing and retrieving binary geometrical shapes in quantum mechanical systems. In contrast to standard procedures in classical computer science in which image reconstruction requires not only the storage of light parameters (like light frequency) but also the storage and use of additional information like correlation and pixel spatial disposition, we show that the employment of maximally entangled qubits allows to reconstruct images without using any additional information. Moreover, we provide a concrete application of our proposal in the field of image recognition and briefly explore potential experimental realizations. Our proposal could be employed to enable emergent quantum technology to be used in high-impact scientific disciplines in which extensive use of image processing is made.

The Gulf of California system presents major challenges to the still developing frameworks for ecosystem-based management (EBM). It is very much an open system and is intermittently subject to important influxes of migratory visitors, including large pelagic predatory fishes and small pelagic forage fishes. These migrants include the more tropical species from the coastal ecosystems to the south and perhaps subtropical sardines and anchovies from the California Current upwelling system. In addition to the multi-annual ENSO-scale and what may seem to be rather erratic episodes of major population incursions, the Gulf presents nonstationary, transient aspects on a variety of longer time scales. Moreover, the removal of top predators by commercial and sport fisheries has introduced trends that must be affecting the entire ecosystem, and certainly the forage fishes that are their major prey base. In addition to size limits, fishing seasons, area closures and license limitations, the fishery is managed by an ad hoc adaptive management system, in which the fishing season can be shortened or additional areas closed to fishing if pre-season exploratory fishing surveys indicate a shortage of small pelagic fishes on the fishing grounds. Whether this system is likely to be sustainable in the long term is difficult to determine, given the potential for rapid changes in the system because of environmental changes and/or feedbacks within the food web. Thus it appears that innovative management frameworks, among other things utilizing the comparative method, may be required in order to determine defensible tradeoffs between precaution and resource utilization.

Satellite-derived time-series of sea sur- face temperature (SST), chlorophyll a, and net primary productivity showed a period of warm SST and low productivity during 1997 and 1999 in the southwestern Gulf of Mexico followed by a period of colder than average SST (2000-2001). This shift between the warm and cold oceanic conditions might have caused significant changes in the structure of the ecosystem that is shown by changes in primary productivity and fishery landings between those periods.

A new calibration method was developed and applied to inductively coupled plasma atomic emission spectrometry. External calibration was performed as follows. A container was filled with a given volume of deionized (V p) water. Then a concentrated standard was introduced at a controlled rate (Q e) into the tank by means of a peristaltic pump. The resulting solution was stirred throughout the experiment. Simultaneously, the solution inside the tank was pumped from the vessel to the plasma at a given rate (Q s). The signal was continuously recorded. The variation of the concentration of the solution leaving the tank with time was determined by applying a basic equation of stirred tanks. The representation of the emission intensity versus the time and the further conversion of the time scale into a concentration scale gave rise to the calibration line. The best results in terms of linearity were achieved for V p=15 cm3, Q e=0.6–0.75 ml min−1 and Q s=1–1.2 ml min−1. Graphs with more than 40 standards were obtained within about 10 min. The results found were not statistically different from those afforded by the conventional calibration method. In addition, the new method was faster and supplied better linearity and precision than the conventional one. Another advantage of the stirred tank was that procedures such as dynamic calibration and standard additions could be easily and quickly applied, thus shortening the analysis time. A complete analysis following these procedures based on the measurement of 30 standards took about 5 min. Several synthetic as well as certified samples (i.e., bovine liver, mussel tissue and powdered milk) were analyzed with the stirred tank by applying four different calibration methodologies (i.e., external calibration, internal calibration, standard additions and a combination of internal standardization and standard additions), with the combination of internal standardization and standard additions being the method that provided the best results. The element concentrations obtained were not significantly different from the actual or certified values.

Tactile needle tip control was used to aid perforation during standard tension-free vaginal tape (TVT) placement to treat urinary incontinence. The success and complications of this novel method were compared retrospectively with the reported results of the standard technique. One hundred nine patients had TVT placement between 1998 and 2001, with follow-up continuing into 2002. Preoperatively, the severity of urinary incontinence was assessed objectively. Postoperatively, TVT effectiveness was assessed subjectively by standardized questionnaire, completed by 78 of the 109 patients (72%). Objective 2-year rates for continence or improvement and most complication rates were similar to previously reported results. Needle tip control was helpful in lowering the occurrence of bladder perforation. Longer postoperative recovery times associated with postoperative dysuria or obstruction did not decrease patient satisfaction if the patient experienced a marked improvement in leakage.

The information on the transitional areas between the temperate and tropical domains at the southern extent of the California Current System is reviewed and described, particularly searching for the relative isolation or interchange between the western coast of the Baja California peninsula and the Gulf of California, as well as mechanisms that permit the existence of sizeable stocks of California sardine. Biological Action Centers that have high productivity throughout the year, as opposed to the rest of the coastal area, are found in both the western coast of the peninsula at the Sebastian Vizcaino—Punta Eugenia region and in the Ballenas Channel inside the gulf; these features support large biomasses of sardine throughout the full year and serve as long term refuges during adverse periods. The role of the Sebastian Vizcaino sardine stock as the primary group for expansion is examined.