A Review of Biomechanics of Arterial Stent Implants

This work looks to provide a review of modern stents by evaluating the need for them as well as providing a detailed engineering analysis of the conditions they are subjected to. It is estimated that over two million of these devices are implanted in patients annually. Of those implanted, a majority are used in the treatment of arteriosclerosis. This disease causes arterial walls to thicken and toughen leading to restricted blood flow and in extreme cases, complete loss of circulation. Arteriosclerosis and complications arising from it form a leading cause of death in the developed world. Although there are a variety of treatment options available, stents have been successfully used for several decades. The review of numerous technical reports infers that stents must withstand complex multi-axial loading conditions while being able to withstand an immense number of loading cycles, making the design and implementation of stents a significant feat

Spelling practices in school districts and regions across the United States and state spelling standards

The authors sent a survey during the 1996-97 school year to 670 school districts in 41 states requesting information on spelling instructional practices to ascertain whether spelling texts are still widely used in the United States given the current emphasis on developmental spelling in the primary grades and the March, 1996 publication of the NCTE/IRA standards. In addition, a search of the reading/language arts standards in 50 states in 1998 revealed that most states do have spelling standards, but only a few coincide with the CTE/IRA Standard 6 which mentions spelling

The Relational Resource Distribution Model: an evaluation of control over nursing practice and the design of nurses’ work

The conception of control over nursing practice (CONP) is examined in the nursing literature along with the business and organizational behavior literature in an effort to reduce the conceptual ambiguity associated with control. Measures for control in the nursing literature are examined. In particular, the number and variation among different scales used to measure control, confounding of disparate conceptions within the same measure, conceptual definitions, dimensionality, reliability, and assessments of validity are investigated that may explain the falsifiability and empirical disconfirmation, threats to construct validity, and the diminution of explanatory power associated with the measurement instability of CONP. The Relational Resource Distribution Model, an investigator developed framework is introduced and evaluated as a relevant tool in the examination and design of nurses' work. The Relational Resource Distribution Model is used to examine the influence of CONP on staff nurse perceptions of patient care quality and job satisfaction. CONP is examined as a 2-dimensional construct with a content dimension related to the sanctioned duties of nurses bound to a special body of knowledge and specific set of nursing skills; and the context dimension of CONP that relates to how nurses perform within the structural dimensions of organization. Both dimensions of control are investigated in different models to explore the differential effects related to each specific dimension. Empirical support from confirmatory factor analytic techniques distinguishes the content dimension of CONP from the context dimension of CONP. Each dimension is evaluated separately at the work-group level for its effects on patient care quality and job satisfaction using hierarchical linear modeling. Content-CONP is a stronger predictor of patient care quality than job satisfaction at the group level of analysis. However, context-CONP is not a significant predictor of either job satisfaction or patient care quality in this analysis for this sample. Lastly, emotional exhaustion is evaluated as a mediator in the CONP-outcome relationship and found to have a significant indirect effect. Indirect effects were confirmed with the Sobel product coefficient test. A 95% CI was established with the use of PRODCLIN, a web-based calculator that uses an asymmetric distribution of the product coefficient resulting in a more accurate estimate

School Administrators’ Self-Efficacy Beliefs and Leadership Styles

The effectiveness of schools, that is, their ability to achieve their pre-determined goals depends on many variables but especially the effectiveness of the administrators who are responsible for the implementation of the educational programs and curricula. An administrator must have a healthy perception of being "an effective administrator" in order to be able to demonstrate expected roles successfully. Concerning school effectiveness, in addition to the emphasis of self-efficacy of administrator, the leadership role of the educational administrators has gained importance with modern educational administration approaches. If an administrator wants to be effective, he/she must act as a leader and convince followers. In this context, when questioning the effectiveness of schools, it is important to determine the level of self-efficacy perceptions of administrators and to determine the leadership styles displayed by them. In this study, it was aimed to examine whether there is a significant relationship between the perceived self-efficacy belief and leadership style. The results show that self-efficacy perceptions of the administrators make a difference in their leadership style and there is a relationship between the self-efficacy belief and exhibitors of transformational leadership behaviors; the more administrators feel themselves efficient, the more they exhibit transformational leadership behaviors

Zirconium metal-water oxidation kinetics. I. Thermometry

A description is given of the thermometry techniques used in the Zirconium Metal--Water Oxidation Kinetics Program. Temperature measurements in the range 900 to 1500$sup 0$C are made in three experimental systems: two oxidation apparatuses and the annealing furnace used in a corollary study of the diffusion of oxygen in $beta$-Zircaloy. Carefully calibrated Pt vs Pt--10 percent Rh thermocouples are employed in all three apparatuses, while a Pt--6 percent Rh vs Pt-- 30 percent Rh thermocouple and an optical pyrometer are used in addition in the annealing furnace. Features of the experimental systems pertaining to thermocouple installation, temperature control, emf measurements, etc. are described, and potential temperature-measurement error sources are discussed in detail. The accuracy of the temperature measurements is analyzed

Long Live The Honey Badger: Robust Asynchronous DPSS and its Applications

Secret sharing is an essential tool for many distributed applications, including distributed key generation and multiparty computation. For many practical applications, we would like to tolerate network churn, meaning participants can dynamically enter and leave the pool of protocol participants as they please. Such protocols, called Dynamic-committee Proactive Secret Sharing (DPSS), have recently been studied; however, existing DPSS protocols do not gracefully handle faults: the presence of even one unexpectedly slow node can often slow down the whole protocol by a factor of $O(n)$. In this work, we explore optimally fault-tolerant asynchronous DPSS that is not slowed down by crash faults and even handles byzantine faults while maintaining the same performance. We first introduce the first high-threshold DPSS, which offers favorable characteristics relative to prior non-synchronous works in the presence of faults while simultaneously supporting higher privacy thresholds. We then batch-amortize this scheme along with a parallel non-high-threshold scheme which achieves optimal bandwidth characteristics. We implement our schemes and demonstrate that they can compete with prior work in best-case performance while outperforming it in non-optimal settings

hbACSS: How to Robustly Share Many Secrets

Despite significant recent progress toward making multi-party computation (MPC) practical, no existing MPC library offers complete robustness---meaning guaranteed output delivery, including in the offline phase---in a network that even has intermittent delays. Importantly, several theoretical MPC constructions already ensure robustness in this setting. We observe that the key reason for this gap between theory and practice is the absence of efficient verifiable/complete secret sharing (VSS/CSS) constructions; existing CSS protocols either require a) challenging broadcast channels in practice or b) introducing computation and communication overhead that is at least quadratic in the number of players. This work presents hbACSS, a suite of optimal-resilience asynchronous complete secret sharing protocols that are (quasi)linear in both computation and communication overhead. Towards developing hbACSS, we develop hbPolyCommit, an efficient polynomial commitment scheme that is (quasi)linear (in the polynomial degree) in terms of computation and communication overhead without requiring a trusted setup. We implement our hbACSS protocols, extensively analyze their practicality, and observe that our protocols scale well with an increasing number of parties. In particular, we use hbACSS to generate MPC input masks: a useful primitive which had previously only been calculated nonrobustly in practice

Towards next generation, low cost, hydrogen resilient austenitic steels: Relating composition, microstructure and deformation modes across length

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SGXonerated: Finding (and Partially Fixing) Privacy Flaws in TEE-based Smart Contract Platforms Without Breaking the TEE

TEE-based smart contracts are an emerging blockchain architecture, offering fully programmable privacy with better performance than alternatives like secure multiparty computation. They can also support compatibility with existing smart contract languages, such that existing (plaintext) applications can be readily ported, picking up privacy enhancements automatically. While previous analysis of TEE-based smart contracts have focused on failures of TEE itself, we asked whether other aspects might be understudied. We focused on state consistency, a concern area highlighted by Li et al., as well as new concerns including access pattern leakage and software upgrade mechanisms. We carried out a code review of a cohort of four TEE-based smart contract platforms. These include Secret Network, the first to market with in-use applications, as well as Oasis, Phala, and Obscuro, which have at least released public test networks. The first and most broadly applicable result is that access pattern leakage occurs when handling persistent contract storage. On Secret Network, its fine-grained access pattern is catastrophic for the transaction privacy of SNIP-20 tokens. If ERC-20 tokens were naively ported to Oasis they would be similarly vulnerable; the others in the cohort leak coarse-grained information at approximately the page level (4 kilobytes). Improving and characterizing this will require adopting techniques from ORAMs or encrypted databases. Second, the importance of state consistency has been underappreciated, in part because exploiting such vulnerabilities is thought to be impractical. We show they are fully practical by building a proof-of-concept tool that breaks all advertised privacy properties of SNIP-20 tokens, able to query the balance of individual accounts and the token amount of each transfer. We additionally demonstrate MEV attacks against the Sienna Swap application. As a final consequence of lacking state consistency, the developers have inadvertently introduced a decryption backdoor through their software upgrade process. We have helped the Secret developers mitigate this through a coordinated vulnerability disclosure, after which their transaction replay defense is roughly on par with the rest