Ultrasonic Doppler measurement of renal artery blood flow

Studies were made of (1) blood flow redistribution during lower body negative pressure (LBNP), (2) the profile of blood flow across the mitral annulus of the heart (both perpendicular and parallel to the commissures), (3) testing and evaluation of a number of pulsed Doppler systems, (4) acute calibration of perivascular Doppler transducers, (5) redesign of the mitral flow transducers to improve reliability and ease of construction, and (6) a frequency offset generator designed for use in distinguishing forward and reverse components of blood flow by producing frequencies above and below the offset frequency. Finally methodology was developed and initial results were obtained from a computer analysis of time-varying Doppler spectra

An exploratory randomised controlled trial comparing telephone and hospital follow-up after treatment for colorectal cancer

Aim:  Following treatment for colorectal cancer it is common practice for patients to attend hospital clinics at regular intervals for routine monitoring, although debate persists on the benefits of this approach. Nurse-led telephone follow-up is effective in meeting information and psycho-social needs in other patient groups. We explored the potential benefits of nurse-led telephone follow-up for colorectal cancer patients. Method:  Sixty-five patients were randomised to either telephone or hospital follow-up in an exploratory randomised trial. Results:  The telephone intervention was deliverable in clinical practice and acceptable to patients and health professionals. Seventy-five percent of eligible patients agreed to randomization. High levels of satisfaction were evident in both study groups. Appointments in the hospital group were shorter (median 14.0 minutes) than appointments in the telephone group (median 28.9 minutes). Patients in the telephone arm were more likely to raise concerns during consultations. Conclusion:  Historical approaches to follow-up unsupported by evidence of effectiveness and efficiency are not sustainable. Telephone follow-up by specialist nurses may be a feasible option. A main trial comparing hospital and telephone follow-up is justified although consideration needs to be given to trial design and practical issues related to the availability of specialist nurses at study locations

Research Notes: Effect of grafting date and maturity of the stock on the flowering behavior of soybean scions

Many crosses made by midwestern U.S. soybean breeders are made between adapted genotypes and genotypes of later maturity. Due to a short growing season, soybean breeders in the northern U. S. are often unable to sufficiently delay planting of adapted genotypes to synchronize flowering with genotypes of later maturity. Photoperiod chambers are expensive and covering plants is time consuming and often produces cleistogamous flowers

Machine Learning Prediction of HEA Properties

High-entropy alloys (HEA) are a very new development in the field of metallurgical materials. They are made up of multiple principle atoms unlike traditional alloys, which contributes to their high configurational entropy. The microstructure and properties of HEAs are are not well predicted with the models developed for more common engineering alloys, and there is not enough data available on HEAs to fully represent the complex behavior of these alloys. To that end, we explore how the use of machine learning models can be used to model the complex, high dimensional behavior in the HEA composition space. Based on our review and experimentation, the use of a variational autoencoder will allow future research to lower the dimensionality (and therefore complexity) of the HEA composition space and allow for novel alloy generation based on one or more desired properties

An analysis of fast photochemistry over high northern latitudes during spring and summer using in-situ observations from ARCTAS and TOPSE

Observations of chemical constituents and meteorological quantities obtained during the two Arctic phases of the airborne campaign ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites) are analyzed using an observationally constrained steady state box model. Measurements of OH and HO_2 from the Penn State ATHOS instrument are compared to model predictions. Forty percent of OH measurements below 2 km are at the limit of detection during the spring phase (ARCTAS-A). While the median observed-to-calculated ratio is near one, both the scatter of observations and the model uncertainty for OH are at the magnitude of ambient values. During the summer phase (ARCTAS-B), model predictions of OH are biased low relative to observations and demonstrate a high sensitivity to the level of uncertainty in NO observations. Predictions of HO_2 using observed CH_2O and H_2O_2 as model constraints are up to a factor of two larger than observed. A temperature-dependent terminal loss rate of HO_2 to aerosol recently proposed in the literature is shown to be insufficient to reconcile these differences. A comparison of ARCTAS-A to the high latitude springtime portion of the 2000 TOPSE campaign (Tropospheric Ozone Production about the Spring Equinox) shows similar meteorological and chemical environments with the exception of peroxides; observations of H_2O_2 during ARCTAS-A were 2.5 to 3 times larger than those during TOPSE. The cause of this difference in peroxides remains unresolved and has important implications for the Arctic HO_x budget. Unconstrained model predictions for both phases indicate photochemistry alone is unable to simultaneously sustain observed levels of CH_2O and H_2O_2; however when the model is constrained with observed CH_2O, H_2O_2 predictions from a range of rainout parameterizations bracket its observations. A mechanism suitable to explain observed concentrations of CH_2O is uncertain. Free tropospheric observations of acetaldehyde (CH_3CHO) are 2–3 times larger than its predictions, though constraint of the model to those observations is sufficient to account for less than half of the deficit in predicted CH_2O. The box model calculates gross O_3 formation during spring to maximize from 1–4 km at 0.8 ppbv d^(−1), in agreement with estimates from TOPSE, and a gross production of 2–4 ppbv d^(−1) in the boundary layer and upper troposphere during summer. Use of the lower observed levels of HO_2 in place of model predictions decreases the gross production by 25–50%. Net O_3 production is near zero throughout the ARCTAS-A troposphere, and is 1–2 ppbv in the boundary layer and upper altitudes during ARCTAS-B

Low latency via redundancy

Low latency is critical for interactive networked applications. But while we know how to scale systems to increase capacity, reducing latency --- especially the tail of the latency distribution --- can be much more difficult. In this paper, we argue that the use of redundancy is an effective way to convert extra capacity into reduced latency. By initiating redundant operations across diverse resources and using the first result which completes, redundancy improves a system's latency even under exceptional conditions. We study the tradeoff with added system utilization, characterizing the situations in which replicating all tasks reduces mean latency. We then demonstrate empirically that replicating all operations can result in significant mean and tail latency reduction in real-world systems including DNS queries, database servers, and packet forwarding within networks

Learning From NCLB: School Responses to Accountability Pressure and Student Subgroup Performance

Much has been written in the last decade about the spotlight that the No Child Left Behind Act (NCLB) shines on schoolperformance. Proponents and opponents alike are quick to discuss the law’s rigid definitions of school performance— exemplified by the classification of schools as making Adequate Yearly Progress (AYP) or not making AYP based largely on annual tests in reading and mathematics, disaggregating school performance by student subgroups, and requiring that all schools reach 100% proficiency. Yet for all its rigidity, the law has offered schools little guidance on how to make use of the performance data that the new systems provide or how to design improvement efforts. As policymakers discuss ways to change NCLB or design new federal education policies targeted at improving academic achievement, we present new research findings that can help to inform those discussions. In this CPRE Policy Brief, we examine the extent to which the assumptions in the law manifest themselves in the actions that school leaders take. This brief asks and answers the question: How do school leaders—administrators and teachers— respond to the results of state assessment systems and the pressure of performance-based accountability? And do those responses seem to matter to achievement outcomes