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The XX model with uniform couplings represents the most natural choice for quantum state transfer through spin chains. Given that it has long been established that single-qubit states cannot be transferred with perfect fidelity in this model, the notion of pretty good state transfer has been recently introduced as a relaxation of the constraints on fidelity. In this paper, we study the transfer of multi-qubit entangled and unentangled states through unmodulated spin chains, and we prove that it is possible to have pretty good state transfer of any multi-particle state. This significantly generalizes the previous results on single-qubit state transfer and opens the way to using uniformly coupled spin chains as short-distance quantum channels for the transfer of arbitrary states of any dimension. Our results could be tested with current technology.

DC bus voltage stability is a critical performance metric for interconnected DC microgrids. However, under severe disturbances, it is prone to transient voltage fluctuations in the bus voltage. Existing control strategies for interconnected microgrids fail to adequately account for the differences in load priorities and voltage requirements among subgrids, making it difficult to ensure the voltage quality of critical subgrids. To address this, this paper proposes a distributed control method for interconnected DC microgrids based on weighted voltage control. With the interlinking converter (IC) as the control core, this method designs a weighted voltage control strategy to balance the transient dynamic characteristics among subgrids without affecting the steady-state control objectives. Finally, a simulation model is established on the PLECS platform, and the efficacy of the suggested strategy has been confirmed.

With data becoming a centerpiece of modern scientific discovery, data sharing by scientists is now a crucial element of scientific progress. This article aims to provide an in-depth examination of the practices and perceptions of data management, including data storage, data sharing, and data use and reuse by scientists around the world. The Usability and Assessment Working Group of DataONE, an NSF-funded environmental cyberinfrastructure project, distributed a survey to a multinational and multidisciplinary sample of scientific researchers in a two-waves approach in 2017-2018. We focused our analysis on examining the differences across age groups, sub-disciplines of science, and sectors of employment. Most respondents displayed what we describe as high and mediocre risk data practices by storing their data on their personal computer, departmental servers or USB drives. Respondents appeared to be satisfied with short-term storage solutions; however, only half of them are satisfied with available mechanisms for storing data beyond the life of the process. Data sharing and data reuse were viewed positively: over 85% of respondents admitted they would be willing to share their data with others and said they would use data collected by others if it could be easily accessed. A vast majority of respondents felt that the lack of access to data generated by other researchers or institutions was a major impediment to progress in science at large, yet only about a half thought that it restricted their own ability to answer scientific questions. Although attitudes towards data sharing and data use and reuse are mostly positive, practice does not always support data storage, sharing, and future reuse. Assistance through data managers or data librarians, readily available data repositories for both long-term and short-term storage, and educational programs for both awareness and to help engender good data practices are clearly needed.

BackgroundWhile national surveys showed declines in e-cigarette use in the USA between 2015 and 2016, recent reports indicate that JUUL, a sleekly designed e-cigarette that looks like a USB drive, is increasingly being used by youth and young adults. However, the extent of JUUL’s growth and its marketing strategy have not been systematically examined.MethodsA variety of data sources were used to examine JUUL retail sales in the USA and its marketing and promotion. Retail store scanner data were used to capture the retail sales of JUUL and other major e-cigarette brands for the period 2011–2017. A list of JUUL-related keywords was used to identify JUUL-related tweets on Twitter; to identify JUUL-related posts, hashtags and accounts on Instagram and to identify JUUL-related videos on YouTube.ResultsIn the short 3-year period 2015–2017, JUUL has transformed from a little-known brand with minimum sales into the largest retail e-cigarette brand in the USA, lifting sales of the entire e-cigarette category. Its US$150 million retail sales in the last quarter of 2017 accounted for about 40% of e-cigarette retail market share. While marketing expenditures for JUUL were moderate, the sales growth of JUUL was accompanied by a variety of innovative, engaging and wide-reaching campaigns on Twitter, Instagram and YouTube, conducted by JUUL and its affiliated marketers.ConclusionsThe discrepancies between e-cigarette sales data and the prevalence of e-cigarette use from surveys highlight the challenges in tracking and understanding the use of new and emerging tobacco products. In a rapidly changing media environment, where successful and influential marketing campaigns can be conducted on social media at little cost, marketing expenditures alone may not fully capture the influence, reach and engagement of tobacco marketing.

The most powerful computer is in a very big need for a reliable random access memory (RAM) which can buffer digital data in. All optical RAM design is introduced in three phases. Those are the loading process phase which describes how data will be entering the closed trap from the line bus. The regeneration process phase which describes how data trapped are regenerated to not to lose its power or get a distortion. As well as the recalling process which describes how trapped data be handled to the line bus is also introduced.

To address the instability of DC bus voltage and AC frequency caused by significant active power fluctuations—such as load transients in hybrid AC/DC microgrids—this paper proposes a hybrid AC/DC microgrid architecture based on a three-port converter, along with a power-adaptive coordinated control method. First, linear coupling equations are derived between the power transmitted by the three-port converter and both the DC bus voltage deviation and the AC frequency deviation. These derivations utilise the active power–frequency (P–f) relationship for the AC microgrid and the active power–voltage (P–V) droop relationship for the DC microgrid. Based on these equations, the balancing power required at each port of the interconnection converter is calculated. Then, the three-port converter employs the power-adaptive coordinated control method to track and balance power across all ports in real time, thereby providing active power support to the corresponding AC or DC microgrid. This ultimately enables adaptive and coordinated operation of the entire hybrid AC/DC microgrid. Finally, a simulation model of the hybrid AC/DC microgrid is built in MATLAB/Simulink, and the results verify the effectiveness of the proposed control strategy.

How to select healthy reference subjects in deriving 99th percentiles for cardiac troponin assays still needs to be clarified. To assist with global implementation of high sensitivity (hs)-cardiac troponin (cTn) I and hs-cTnT assays in clinical practice, we determined overall and sex-specific 99th percentiles in 9 hs-cTnI and 3 hs-cTnT assays using a universal sample bank (USB). The Universal Sample Bank (USB) comprised healthy subjects, 426 men and 417 women, screened using a health questionnaire. Hemoglobin A1c (>URL 6.5%), NT-proBNP (>URL 125 ng/L) and eGFR (<60 mL/min), were used as surrogate biomarker exclusion criteria along with statin use. 99th percentiles were determined by nonparametric, Harrell--Davis bootstrap, and robust methods. Subjects were ages 19 to 91 years, Caucasian 58%, African American 27%, Pacific Islander/Asian 11%, other 4%, Hispanic 8%, and non-Hispanic 92%. The overall and sex-specific 99th percentiles for all assays, before and after exclusions (n = 694), were influenced by the statistical method used, with substantial differences noted between and within both hs-cTnI and hs-cTnT assays. Men had higher 99th percentiles (ng/L) than women. The Roche cTnT and Beckman and Abbott cTnI assays (after exclusions) did not measure cTn values at ≥ the limit of detection in ≥50% women. Our findings have important clinical implications in that sex-specific 99th percentiles varied according to the statistical method and hs-cTn assay used, not all assays provided a high enough percentage of measurable concentrations in women to qualify as a hs-assay, and the surrogate exclusion criteria used to define normality tended to lower the 99th percentiles.

This paper proposes a simple DC bus voltage regulation strategy for a dual three-phase permanent magnet synchronous generator (DTP-PMSG). The strategy combines the multi-step commutation sequence and a Pulse Width Modulation (PWM) channel that adjusts the zero-vector dwell according to an outer PI loop on DC bus voltage. In doing so, the effective stator voltage magnitude, which is primarily the quadrature axis component, is trimmed without altering sector scheduling or increasing switching complexity. Experiments on a laboratory DTP-PMSG platform with two three-phase voltage-source rectifiers validate the approach. The results show that the proposed strategy achieves stable DC bus regulation.

To achieve the optimal design of the DC-bus shunt capacitance in an underwater Bidirectional Wireless Power Transfer (BWPT) system, which balances volume, cost, and performance, this paper proposes a universal calculation method for determining the minimum required capacitance on the output side, applicable to various compensation topologies. Using the bilateral LCC compensation network as an example, the mathematical relationship between the minimum capacitance and system output power, switching frequency, and allowable voltage ripple is theoretically derived. Furthermore, the general applicability principle of this method to other compensation networks is elucidated. Experimental results demonstrate that the capacitance value determined by the proposed method ensures the output voltage ripple is strictly constrained within the design target of Y% during rated power operation, thereby validating the correctness and effectiveness of the approach.

Practice-/policy-oriented abstract: Understanding why employees do or do not comply with information systems security (ISS) procedures is an imperative in today’s organizations whose futures often depend on how well they protect and harness information assets. We use a predominantly inductive approach to develop a theoretical understanding of how employees’ reasons for engaging to ISS behaviors (ISSBs) change over time, using ideas from dialectics as our scaffolding. Our dialectical view of this process suggests that explanations for engaging in different ISSBs change over time as individuals seek to balance contradictory demands. Furthermore, our view suggests that new experiences and external events initiate a process of reevaluating tensions that can in turn lead to behavioral changes. Based on our observations and interpretation, we conclude that it is beneficial for ISS practitioners not only to be aware of factors that seem to promote compliance with ISSPs, but also to pay attention to the importance of opposing values and pressures, triggers, and ways to resolve the existing tensions related to an individual’s ISSBs. This will likely enable awareness about the dilemmas that individuals confront in ISS-related situations and potentially contribute to the design of better controls and procedures for ensuring compliant ISSBs. The various guidelines, procedures, and policies referred to as information systems security procedures (ISSPs) underlie information systems security behaviors (ISSBs) of many employees in organizations. Understanding the reasons for ISSBs—that is, why employees do or do not comply with ISSPs—is an imperative in today’s organizations, given that information is a valuable asset. In our study, we observed that employees’ reasons for engaging in ISSBs, such as selecting a password, locking a computer, and using a USB memory device, changed over time. Noting that the dynamic nature of ISSBs has not yet received sufficient consideration in information systems security (ISS) research, we use a predominantly inductive approach to develop a theoretical understanding of the ISSB change process, sensitized by ideas from dialectics. Our dialectical process view suggests that explanations for engaging in different ISSBs are not static but change over time as individuals seek to deal with, or balance, tensions or contradictory demands. Furthermore, our view suggests that “change triggers” (e.g., new experiences and external events) initiate a process of reevaluating tensions that can, in turn, lead to changes in ISSBs. A number of implications for future research and practice emerge from this dialectical understanding of the ISSB change process. The online appendix is available at https://doi.org/10.1287/isre.2018.0827 .