Denoising single MR spectra by deep learning: Miracle or mirage?

PURPOSE The inherently poor SNR of MRS measurements presents a significant hurdle to its clinical application. Denoising by machine or deep learning (DL) was proposed as a remedy. It is investigated whether such denoising leads to lower estimate uncertainties or whether it essentially reduces noise in signal-free areas only. METHODS Noise removal based on supervised DL with U-nets was implemented using simulated 1 H MR spectra of human brain in two approaches: (1) via time-frequency domain spectrograms and (2) using 1D spectra as input. Quality of denoising was evaluated in three ways: (1) by an adapted fit quality score, (2) by traditional model fitting, and (3) by quantification via neural networks. RESULTS Visually appealing spectra were obtained; hinting that denoising is well-suited for MRS. However, an adapted denoising score showed that noise removal is inhomogeneous and more efficient for signal-free areas. This was confirmed by quantitative analysis of traditional fit results as well as DL quantitation following DL denoising. DL denoising, although apparently successful as judged by mean squared errors, led to substantially biased estimates in both implementations. CONCLUSION The implemented DL-based denoising techniques may be useful for display purposes, but do not help quantitative evaluations, confirming expectations based on estimation theory: Cramér Rao lower bounds defined by the original data and the appropriate fitting model cannot be circumvented in an unbiased way for single data sets, unless additional prior knowledge can be incurred in the form of parameter restrictions/relations or applicable substates

Analysis and Assessment of the Reimbursement Rates and Mechanisms for Kentucky’s Publicly Funded Ferries

The Kentucky Transportation Cabinet (KYTC) reimburses publicly operated ferries, including when they cease operations due to severe weather or unforeseen events. Reimbursement procedures are not codified in law and are largely based on historical practice. To determine how the Cabinet should handle reimbursement, funding, oversight of ferry services moving forward, the Kentucky Transportation Center (KTC) reviewed practices adopted by 10 other states and conducted a detailed analysis of Kentucky’s current approach. Of the states KTC examined, only Tennessee reimburses ferry operations for closures (at 50 percent of the normal hourly rate for a period up to 48 hours). Half of the states KTC examined make state funding available for ferry operations, others either devolve oversight to the local level or provide no funding assistance. In Kentucky, operating standards for ferry services are not consistent and no uniform method has been devised to calculate reimbursement rates. In light of these findings, KYTC should create detailed auditing guidelines to improve the consistency of ferry service financial statements; pursue funding sources it has not previously taken advantage of, and generate long-term forecasts of the state’s ferry operations. Lastly, the Cabinet should ask the General Assembly to revisit and modify several statutes pertaining to ferries which contain outdated language that has little relevance to the modern transportation system

Quantification of MR spectra by deep learning in an idealized setting: Investigation of forms of input, network architectures, optimization by ensembles of networks, and training bias.

PURPOSE The aims of this work are (1) to explore deep learning (DL) architectures, spectroscopic input types, and learning designs toward optimal quantification in MR spectroscopy of simulated pathological spectra; and (2) to demonstrate accuracy and precision of DL predictions in view of inherent bias toward the training distribution. METHODS Simulated 1D spectra and 2D spectrograms that mimic an extensive range of pathological in vivo conditions are used to train and test 24 different DL architectures. Active learning through altered training and testing data distributions is probed to optimize quantification performance. Ensembles of networks are explored to improve DL robustness and reduce the variance of estimates. A set of scores compares performances of DL predictions and traditional model fitting (MF). RESULTS Ensembles of heterogeneous networks that combine 1D frequency-domain and 2D time-frequency domain spectrograms as input perform best. Dataset augmentation with active learning can improve performance, but gains are limited. MF is more accurate, although DL appears to be more precise at low SNR. However, this overall improved precision originates from a strong bias for cases with high uncertainty toward the dataset the network has been trained with, tending toward its average value. CONCLUSION MF mostly performs better compared to the faster DL approach. Potential intrinsic biases on training sets are dangerous in a clinical context that requires the algorithm to be unbiased to outliers (i.e., pathological data). Active learning and ensemble of networks are good strategies to improve prediction performances. However, data quality (sufficient SNR) has proven as a bottleneck for adequate unbiased performance-like in the case of MF

Walks of molecular motors in two and three dimensions

Molecular motors interacting with cytoskeletal filaments undergo peculiar random walks consisting of alternating sequences of directed movements along the filaments and diffusive motion in the surrounding solution. An ensemble of motors is studied which interacts with a single filament in two and three dimensions. The time evolution of the probability distribution for the bound and unbound motors is determined analytically. The diffusion of the motors is strongly enhanced parallel to the filament. The analytical expressions are in excellent agreement with the results of Monte Carlo simulations.Comment: 7 pages, 2 figures, to be published in Europhys. Let

Analysis of Truck Weight Limit Regulations

In the United States vehicle weight limits are set by laws and regulations enacted at the state and federal levels. On interstates the maximum allowable gross vehicle weight is 80,000 lbs. States use different rules for permitting overdimensional and overweight (OD/OW) vehicles, and most have carve outs that exempt specific commodities from standard weight limits. This results in a complex legal and regulatory landscape that enforcement personnel can find difficult to negotiate. This report discusses strategies that can be adopted in the state of Kentucky to improve enforcement and mitigate infrastructure damage caused by OD/OW loads. After presenting a thorough review of laws pertaining to vehicle weight limits at the national and state levels, the report presents the results of a nationwide survey administered to agency staff directly involved in weight limit enforcement. Survey respondents reported that OW trucks inflict a disproportionate amount of damage on pavements and bridges that permitting fees and fuel taxes are insufficient to ameliorate roadway damage caused by these vehicles, and that commodity exemptions and staff shortages make enforcement a challenging proposition. In addition to sharing many of the opinions of agency staff elsewhere, Kentucky personnel said that many bridges and roadways are not designed to withstand repeated loads of 80,000 lbs. of gross vehicle weight, heavier vehicles with commodity exemptions are especially damaging to collector and local roads, and that enforcement efforts need to be redoubled. Recommendations for improving weight limit enforcement in Kentucky cover areas such as legislation (e.g., reducing the number of commodity exemptions, using axle-based weight limits), highway design, enforcement and judicial practices, and permitting and fees. Implementing these recommendations can help Kentucky modernize and standardize its enforcement efforts

Stakeholder involvement in systematic reviews: a protocol for a systematic review of methods, outcomes and effects

Background There is an expectation for stakeholders (including patients, the public, health professionals, and others) to be involved in research. Researchers are increasingly recognising that it is good practice to involve stakeholders in systematic reviews. There is currently a lack of evidence about (A) how to do this and (B) the effects, or impact, of such involvement. We aim to create a map of the evidence relating to stakeholder involvement in systematic reviews, and use this evidence to address the two points above. Methods We will complete a mixed-method synthesis of the evidence, first completing a scoping review to create a broad map of evidence relating to stakeholder involvement in systematic reviews, and secondly completing two contingent syntheses. We will use a stepwise approach to searching; the initial step will include comprehensive searches of electronic databases, including CENTRAL, AMED, Embase, Medline, Cinahl and other databases, supplemented with pre-defined hand-searching and contacting authors. Two reviewers will undertake each review task (i.e., screening, data extraction) using standard systematic review processes. For the scoping review, we will include any paper, regardless of publication status or study design, which investigates, reports or discusses involvement in a systematic review. Included papers will be summarised within structured tables. Criteria for judging the focus and comprehensiveness of the description of methods of involvement will be applied, informing which papers are included within the two contingent syntheses. Synthesis A will detail the methods that have been used to involve stakeholders in systematic reviews. Papers from the scoping review that are judged to provide an adequate description of methods or approaches will be included. Details of the methods of involvement will be extracted from included papers using pre-defined headings, presented in tables and described narratively. Synthesis B will include studies that explore the effect of stakeholder involvement on the quality, relevance or impact of a systematic review, as identified from the scoping review. Study quality will be appraised, data extracted and synthesised within tables. Discussion This review should help researchers select, improve and evaluate methods of involving stakeholders in systematic reviews. Review findings will contribute to Cochrane training resources

Interhospital transportation of mass burn casualties

Aim of Study: To establish the impact of the transportation on the condition and outcome of the victims of the Volendam fire incident. Methods: Medical and logistic parameters from all victims in the Intensive Care Unit (ICU) were retrospectively collected. Physiologic parameters in the first 24 h and outcome parameters were compared between the transported and the non-transported patients. Results: The first 24 h, 105 patients were admitted to an ICU: 47 of them were relocated during that same day. The pH value was significantly lower in the transported group (p = 0.016). Systolic blood pressure, bicarbonate, carbon dioxide, temperature, APACHE II score and fluctuation during the first day, as well as condition during the sec

A Review of Kentucky’s Extended-Weight Hauling Programs

Kentucky established its Extended Weight Coal or Coal By-products Haul Road System (EWCHRS) to increase the state’s competitiveness within the coal industry and reduce financial burdens on coal haulers. A new extended-weight haul system for unrefined petroleum products will come online in 2022. To facilitate enforcement of weight limits throughout Kentucky, this report surveys literature on how overweight vehicles affect roads and bridges, describes statutes and regulations governing weight limits in the state, discusses policies and strategies used throughout the US to handle overweight vehicles, and makes recommendations for improving extended-weight policies in Kentucky. It is apparent that pavements and bridges repeatedly exposed to overweight vehicles have shorter life-cycles, but methods for quantifying deterioration rates are lacking. In both Kentucky and throughout the US, agency personnel find that not enough revenues are collected from permitting fees to offset damage caused by overweight trucks. The enforcement landscape is made complex by exemptions that apply to specific industries and commodities. Without adequate staffing and weigh station operations, robust enforcement of weight limits is very challenging. Some of the recommendations for Kentucky to improve its extended-weight policies include studying the feasibility of a statewide long-haul network that accommodates all commodities, modifying the EWCHRS fee structure to generate enough funds to repair damage inflicted by overweight vehicles, strengthen enforcement of weight limits on the EWCHRS, mandate installation of GPS systems on vehicles that travel the EWCHRS to streamline mileage reporting and improve driver awareness of prohibited routes, and eliminate inconsistencies, ambiguities, and redundancies in regulatory and statutory language

Molecular Motor of Double-Walled Carbon Nanotube Driven by Temperature Variation

An elegant formula for coordinates of carbon atoms in a unit cell of a single-walled nanotube (SWNT) is presented and a new molecular motor of double-walled carbon nanotube whose inner tube is a long (8,4) SWNT and outer tube a short (14,8) SWNT is constructed. The interaction between inner an outer tubes is analytically derived by summing the Lennard-Jones potentials between atoms in inner and outer tubes. It is proved that the molecular motor in a thermal bath exhibits a directional motion with the temperature variation of the bath.Comment: 9 pages, 4 figures, revtex