Building Sustainable Pavements with Concrete: Briefing Document

It is becoming increasingly apparent that some human activities and development practices are negatively affecting the well-being of the planet and putting future generations at risk. Public agencies are recognizing the paramount importance of adopting more “sustainable” practices and products—those that preserve or enhance economic, environmental, and social well-being—in designing, constructing, and maintaining public infrastructure, including pavements. Owners of the nation’s roadway system are beginning to consider imposing sustainability measures in their contracts. This is an important step toward a more sustainable infrastructure. But pavement owners, designers, material suppliers, and contractors are handicapped by two features of the paving community: (1) the lack of practical information about pavement sustainability and (2) the many other critical needs that compete with sustainability for attention and resources

Quasi-static aberrations induced by laser guide stars in adaptive optics

Laser Guide Star Adaptive Optics (LGS AO) systems use the return from an artificial guide star to measure the wavefront aberrations in the direction of the science object. We observe quasi-static differences between the measured wavefront and the wavefront aberration of the science object. This paper quantifies and explains the source of the difference between the wavefronts measured using an LGS and a natural guide star at the W. M. Keck Observatory, which can be as high as 1000 nm RMS

Expectation Values from the Single-Layer Quantum Approximate Optimization Algorithm on Ising Problems

We report on the energy-expectation-value landscapes produced by the single-layer ($p=1$) Quantum Approximate Optimization Algorithm (QAOA) when being used to solve Ising problems. The landscapes are obtained using an analytical formula that we derive. The formula allows us to predict the landscape for any given Ising problem instance and consequently predict the optimal QAOA parameters for heuristically solving that instance using the single-layer QAOA. We have validated our analytical formula by showing that it accurately reproduces the landscapes published in recent experimental reports. We then applied our methods to address the question: how well is the single-layer QAOA able to solve large benchmark problem instances? We used our analytical formula to calculate the optimal energy-expectation values for benchmark MAX-CUT problems containing up to $7\,000$ vertices and $41\,459$ edges. We also calculated the optimal energy expectations for general Ising problems with up to $100\,000$ vertices and $150\,000$ edges. Our results provide an estimate for how well the single-layer QAOA may work when run on a quantum computer with thousands of qubits. In addition to providing performance estimates when optimal angles are used, we are able to use our analytical results to investigate the difficulties one may encounter when running the QAOA in practice for different classes of Ising instances. We find that depending on the parameters of the Ising Hamiltonian, the expectation-value landscapes can be rather complex, with sharp features that necessitate highly accurate rotation gates in order for the QAOA to be run optimally on quantum hardware. We also present analytical results that explain some of the qualitative landscape features that are observed numerically.Comment: 24 pages, 15 figure

Increased Cerebrospinal Fluid Production as a Possible Mechanism Underlying Caffeine's Protective Effect against Alzheimer's Disease

Alzheimer's disease (AD), the most common type of dementia among older people, is characterized by the accumulation of β-amyloid (Aβ) senile plaques and neurofibrillary tangles composed of hyperphosphorylated tau in the brain. Despite major advances in understanding the molecular etiology of the disease, progress in the clinical treatment of AD patients has been extremely limited. Therefore, new and more effective therapeutic approaches are needed. Accumulating evidence from human and animal studies suggests that the long-term consumption of caffeine, the most commonly used psychoactive drug in the world, may be protective against AD. The mechanisms underlying the suggested beneficial effect of caffeine against AD remain to be elucidated. In recent studies, several potential neuroprotective effects of caffeine have been proposed. Interestingly, a recent study in rats showed that the long-term consumption of caffeine increased cerebrospinal fluid (CSF) production, associated with the increased expression of Na+-K+ ATPase and increased cerebral blood flow. Compromised function of the choroid plexus and defective CSF production and turnover, with diminished clearance of Aβ, may be one mechanism implicated in the pathogenesis of late-onset AD. If reduced CSF turnover is a risk factor for AD, then therapeutic strategies to improve CSF flow are reasonable. In this paper, we hypothesize that long-term caffeine consumption could exert protective effects against AD at least in part by facilitating CSF production, turnover, and clearance. Further, we propose a preclinical experimental design allowing evaluation of this hypothesis

Are Costs of Robot-Assisted Surgery Warranted for Gynecological Procedures?

The exponential use of robotic surgery is not the result of evidence-based benefits but mainly driven by the manufacturers, patients and enthusiastic surgeons. The present review of the literature shows that robot-assisted surgery is consistently more expensive than video-laparoscopy and in many cases open surgery. The average additional variable cost for gynecological procedures was about 1600 USD, rising to more than 3000 USD when the amortized cost of the robot itself was included. Generally most robotic and laparoscopic procedures have less short-term morbidity, blood loss, intensive care unit, and hospital stay than open surgery. Up to now no major consistent differences have been found between robot-assisted and classic video-assisted procedures for these factors. No comparative data are available on long-term morbidity and oncologic outcome after open, robotic, and laparoscopic gynecologic surgery. It seems that currently only for very complex surgical procedures, such as cardiac surgery, the costs of robotics can be competitive to open surgical procedures. In order to stay viable, robotic programs will need to pay for themselves on a per case basis and the costs of robotic surgery will have to be reduced

The relation of 12 lead ECG to the cardiac anatomy: The normal CineECG.

Abstract Background The interpretation of the 12‑lead ECG is notoriously difficult and requires experts to distinguish normal from abnormal ECG waveforms. ECG waveforms depend on body build and electrode positions, both often different in males and females. To relate the ECG waveforms to cardiac anatomical structures is even more difficult. The novel CineECG algorithm enables a direct projection of the 12‑lead ECG to the cardiac anatomy by computing the mean location of cardiac activity over time. The aim of this study is to investigate the cardiac locations of the CineECG derived from standard 12‑lead ECGs of normal subjects. Methods In this study we used 6525 12‑lead ECG tracings labelled as normal obtained from the certified Physionet PTB XL Diagnostic ECG Database to construct the CineECG. All 12 lead ECGs were analyzed, and then divided by age groups (18–29,30-39,40-49,50-59,60-69,70–100 years) and by gender (male/female). For each ECG, we computed the CineECG within a generic 3D heart/torso model. Based on these CineECG's, the average normal cardiac location and direction for QRS, STpeak, and TpeakTend segments were determined. Results The CineECG direction for the QRS segment showed large variation towards the left free wall, whereas the STT segments were homogeneously directed towards the septal/apical region. The differences in the CineECG location for the QRS, STpeak, and TpeakTend between the age and gender groups were relatively small (maximally 10 mm at end T-wave), although between the gender groups minor differences were found in the 4 chamber direction angles (QRS 4°, STpeak 5°, and TpeakTend 8°) and LAO (QRS 1°, STpeak 13°, and TpeakTend 30°). Conclusion CineECG demonstrated to be a feasible and pragmatic solution for ECG waveform interpretation, relating the ECG directly to the cardiac anatomy. The variations in depolarization and repolarization CineECG were small within this group of normal healthy controls, both in cardiac location as well as in direction. CineECG may enable an easier discrimination between normal and abnormal QRS and T-wave morphologies, reducing the amount of expert training. Further studies are needed to prove whether novel CineECG can significantly contribute to the discrimination of normal versus abnormal ECG tracings