University of Rhode Island

About: University of Rhode Island is a education organization based out in Kingston, Rhode Island, United States. It is known for research contribution in the topics: Population & Bay. The organization has 11464 authors who have published 22770 publications receiving 841066 citations. The organization is also known as: URI & Rhode Island College of Agriculture and the Mechanic Arts.

Study of stability of time-domain features for electromyographic pattern recognition

Abstract: Significant progress has been made towards the clinical application of human-machine interfaces (HMIs) based on electromyographic (EMG) pattern recognition for various rehabilitation purposes. Making this technology practical and available to patients with motor deficits requires overcoming real-world challenges, such as physical and physiological changes, that result in variations in EMG signals and systems that are unreliable for long-term use. In this study, we aimed to address these challenges by (1) investigating the stability of time-domain EMG features during changes in the EMG signals and (2) identifying the feature sets that would provide the most robust EMG pattern recognition. Variations in EMG signals were introduced during physical experiments. We identified three disturbances that commonly affect EMG signals: EMG electrode location shift, variation in muscle contraction effort, and muscle fatigue. The impact of these disturbances on individual features and combined feature sets was quantified by changes in classification performance. The robustness of feature sets was evaluated by a stability index developed in this study. Muscle fatigue had the smallest effect on the studied EMG features, while electrode location shift and varying effort level significantly reduced the classification accuracy for most of the features. Under these disturbances, the most stable EMG feature set with combination of four features produced at least 16.0% higher classification accuracy than the least stable set. EMG autoregression coefficients and cepstrum coefficients showed the most robust classification performance of all studied time-domain features. Selecting appropriate EMG feature combinations can overcome the impact of the studied disturbances on EMG pattern classification to a certain extent; however, this simple solution is still inadequate. Stabilizing electrode contact locations and developing effective classifier training strategies are suggested to further improve the robustness of HMIs based on EMG pattern recognition.

Global Carbon Sinks and Their Variability Inferred from Atmospheric O2 and δ13C

Abstract: Recent time-series measurements of atmospheric O2 show that the land biosphere and world oceans annually sequestered 1.4 ± 0.8 and 2.0 ± 0.6 gigatons of carbon, respectively, between mid-1991 and mid-1997. The rapid storage of carbon by the land biosphere from 1991 to 1997 contrasts with the 1980s, when the land biosphere was approximately neutral. Comparison with measurements of δ13CO2 implies an isotopic flux of 89 ± 21 gigatons of carbon per mil per year, in agreement with model- and inventory-based estimates of this flux. Both the δ13C and the O2 data show significant interannual variability in carbon storage over the period of record. The general agreement of the independent estimates from O2and δ13C is a robust signal of variable carbon uptake by both the land biosphere and the oceans.

The Transtheoretical Model of Change and HIV Prevention: A Review:

Abstract: The transtheoretical model of health behavior change is described and supporting empirical work is presented that reviews the central constructs of the model: the stages of change, processes of change, decisional balance, confidence, and temptation. Model-based applications to a broad range of problem behaviors are summarized. Applications to human immunodeficiency virus (HIV) prevention behavior changes are highlighted for each variable. Finally, several questions about the area of sexual behavior change to reduce risk of HIV exposure are explored and future research ideas are described within the context of this model.

The spray drying of pharmaceuticals

Abstract: (1992). The spray drying of pharmaceuticals. Drug Development and Industrial Pharmacy: Vol. 18, No. 11-12, pp. 1169-1206.