Learning from the past with experiment databases

Thousands of Machine Learning research papers contain experimental comparisons that usually have been conducted with a single focus of interest, and detailed results are usually lost after publication. Once past experiments are collected in experiment databases they allow for additional and possibly much broader investigation. In this paper, we show how to use such a repository to answer various interesting research questions about learning algorithms and to verify a number of recent studies. Alongside performing elaborate comparisons and rankings of algorithms, we also investigate the effects of algorithm parameters and data properties, and study the learning curves and bias-variance profiles of algorithms to gain deeper insights into their behavior

Heat and salinity budgets at the Stratus mooring in the southeast Pacific

Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 119 (2014): 8162–8176, doi:10.1002/2014JC010256.The surface layer of the southeast Pacific Ocean (SEP) requires an input of cold, fresh water to balance heat gain, and evaporation from air-sea fluxes. Models typically fail to reproduce the cool sea surface temperatures (SST) of the SEP, limiting our ability to understand the variability of this climatically important region. We estimate the annual heat budget of the SEP for the period 2004–2009, using data from the upper 250 m of the Stratus mooring, located at 85°W 20°S, and from Argo floats. The surface buoy measures meteorological conditions and air-sea fluxes; the mooring line is heavily instrumented, measuring temperature, salinity, and velocity at more than 15 depth levels. We use a new method for estimating the advective component of the heat budget that combines Argo profiles and mooring velocity data, allowing us to calculate monthly profiles of heat advection. Averaged over the 6 year study period, we estimate a cooling advective heat flux of −41 ± 29 W m−2, accomplished by a combination of the mean gyre circulation, Ekman transport, and eddies. This compensates for warming fluxes of 32 ± 4 W m−2 due to air-sea fluxes and 7 ± 9 W m−2 due to vertical mixing and Ekman pumping. A salinity budget exhibits a similar balance, with advection of freshwater (−60 psu m) replenishing the freshwater lost through evaporation (47 psu m) and Ekman pumping (14 psu m).This work was supported by NOAA's Climate Program Office and by NSF grant OCE-0745508.2015-05-2

Investigation of non-uniform airflow signal oscillation during high frequency chest compression

BACKGROUND: High frequency chest compression (HFCC) is a useful and popular therapy for clearing bronchial airways of excessive or thicker mucus. Our observation of respiratory airflow of a subject during use of HFCC showed the airflow oscillation by HFCC was strongly influenced by the nonlinearity of the respiratory system. We used a computational model-based approach to analyse the respiratory airflow during use of HFCC. METHODS: The computational model, which is based on previous physiological studies and represented by an electrical circuit analogue, was used for simulation of in vivo protocol that shows the nonlinearity of the respiratory system. Besides, airflow was measured during use of HFCC. We compared the simulation results to either the measured data or the previous research, to understand and explain the observations. RESULTS AND DISCUSSION: We could observe two important phenomena during respiration pertaining to the airflow signal oscillation generated by HFCC. The amplitudes of HFCC airflow signals varied depending on spontaneous airflow signals. We used the simulation results to investigate how the nonlinearity of airway resistance, lung capacitance, and inertance of air characterized the respiratory airflow. The simulation results indicated that lung capacitance or the inertance of air is also not a factor in the non-uniformity of HFCC airflow signals. Although not perfect, our circuit analogue model allows us to effectively simulate the nonlinear characteristics of the respiratory system. CONCLUSION: We found that the amplitudes of HFCC airflow signals behave as a function of spontaneous airflow signals. This is due to the nonlinearity of the respiratory system, particularly variations in airway resistance

Structure and surface properties of eddies in the southeast Pacific Ocean

Author Posting. © American Geophysical Union, 2013. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 118 (2013): 2295–2309, doi:10.1002/jgrc.20175.A number of studies have posited that coastally generated eddies could cool the southeast Pacific Ocean (SEP) by advecting cool, upwelled waters offshore. We examine this mechanism by characterizing the upper-ocean properties of mesoscale eddies in the SEP with a variety of observations and by estimating the surface-layer eddy heat flux divergence with satellite data. Cyclonic and anticyclonic eddies observed during two cruises featured deep positive salinity anomalies along the 26.5 kg m−3isopycnal, indicating that the eddies had likely trapped and transported coastal waters offshore. The cyclonic eddies observed during the cruises were characterized by shoaling isopycnals in the upper 200 m and cool near-surface temperature anomalies, whereas the upper-ocean structure of anticyclonic eddies was more variable. Using a variety of large-scale observations, including Argo float profiles, drifter records, and satellite sea surface temperature fields, we show that, relative to mean conditions, cyclonic eddies are associated with cooler surface temperatures and that anticyclonic eddies are associated with warmer surface temperatures. Within each data set, the mean eddy surface temperature anomalies are small and of approximately equal magnitude but opposite sign. Eddy statistics drawn from satellite altimetry data reveal that cyclonic and anticyclonic eddies occur with similar frequency and have similar average radii in the SEP. A satellite-based estimate of the surface-layer eddy heat flux divergence, while large in coastal regions, is small when averaged over the SEP, suggesting that eddies do not substantially contribute to cooling the surface layer of the SEP.This work was supported by NOAA’s Climate Program Office and by NSF Grant OCE-0745508. Microwave OI SST data are produced by Remote Sensing Systems and sponsored by National Oceanographic Partnership Program (NOPP), the NASA Earth Science Physical Oceanography Program, and the NASA MEaSUREs DISCOVER Project

Higher levels of bodily pain in people with long-term type 1 diabetes: associations with quality of life, depressive symptoms, fatigue and glycaemic control – the Dialong study

Aims To compare reported level of bodily pain, overall and health‐related quality of life (QoL), depression and fatigue in people with long‐term type 1 diabetes vs. a comparison group without diabetes. Further, to examine the associations of total bodily pain with QoL, depression, fatigue and glycaemic control in the diabetes group. Methods Cross‐sectional study of 104 (76% of eligible) people with type 1 diabetes of ≥ 45 years’ duration attending the Norwegian Diabetes Centre and 75 persons without diabetes who completed questionnaires measuring bodily pain (RAND‐36 bodily pain domain), shoulder pain (Shoulder Pain and Disability Index), hand pain (Australian/Canadian Osteoarthritis Hand Index), overall QoL (World Health Organization Quality of Life – BREF), health‐related QoL (RAND‐36), diabetes‐specific QoL (Audit of Diabetes‐Dependent Quality of Life; only diabetes group), depression (Patient Health Questionnaire) and fatigue (Fatigue questionnaire). For people with type 1 diabetes, possible associations between the bodily pain domain (lower scores indicate higher levels of bodily pain) and other questionnaire scores, were measured with regression coefficients (B) per 10‐unit increase in bodily pain score from linear regression. Results The diabetes group reported higher levels of bodily (P = 0.003), shoulder and hand pain (P < 0.001) than the comparison group. In the diabetes group, bodily pain was associated with lower overall and diabetes‐specific QoL [B (95% confidence intervals)]: 0.2 (0.1, 0.2) and 0.2 (0.1, 0.3); higher levels of depression −1.0 (−1.3, −0.7) and total fatigue −1.5 (−1.9, −1.2); and worse glycaemic control HbA1c (mmol/mol; %) −0.8 (−1.5, −0.1); −0.1 (−0.1, −0.01). Conclusions People with long‐term type 1 diabetes experience a high level of bodily pain compared with a comparison group. Total bodily pain was associated with worse QoL and glycaemic control.publishedVersio

Effect of intraoperative fluid optimisation on renal function in patients undergoing emergency abdominal surgery; a randomised controlled pilot study (ISRCTN 11799696) Fluid optimisation for emergency surgery

&lt;b&gt;Background:&lt;/b&gt; Emergency abdominal surgery carries a high risk of postoperative morbidity and mortality. Goal directed therapy has been advocated to improve outcome in high-risk surgery. The aim of the present pilot study was to examine the effect of goal directed therapy using fluid alone on postoperative renal function and organ failure score in patients undergoing emergency abdominal surgery. &lt;b&gt;Methods:&lt;/b&gt; This prospective randomised pilot study included patients over the age of 50 undergoing emergency abdominal surgery. In the intervention group pulse pressure variation measurements were used to guide fluid boluses of 6% Hydroxyethylstarch 130/0.4. The control group received standard care. Serum urea, creatinine and cystatin C levels were measured prior to and at the end of surgery and postoperatively on day 1, day 3 and day 5. &lt;b&gt;Results:&lt;/b&gt; Thirty patients were recruited. One patient died prior to surgery and was excluded from the analysis. The intervention group received a median of 750ml of hydroxyethylstarch. The peak values of postoperative urea were 6.9 (2.7–31.8) vs. 6.4 (3.5–11.5)mmol/l (p=0.425), creatinine 100 (60–300) vs. 85 (65–150) μmol/l (p=0.085) and cystatin C 1.09 (0.66–4.94) vs. 1.01 (0.33–2.29)mg/dl (p=0.352) in the control and intervention group, respectively. &lt;b&gt;Conclusions:&lt;/b&gt; In the present pilot study replacing the identified fluid deficit was not associated with a change in renal function. These results do not preclude that goal directed therapy using fluid alone may have an effect on renal function but they would suggest that the effect size of fluid optimisation alone on renal function is small

Rapid export of waters formed by convection near the Irminger Sea's western boundary

The standard view of the overturning circulation emphasizes the role of convection, yet for waters to contribute to overturning, they must not only be transformed to higher densities but also exported equatorward. From novel mooring observations in the Irminger Sea (2014–2016), we describe two water masses that are formed by convection and show that they have different rates of export in the western boundary current. Upper Irminger Sea Intermediate Water appears to form near the boundary current and is exported rapidly within 3 months of its formation. Deep Irminger Sea Intermediate Water forms in the basin interior and is exported on longer time scales. The subduction of these waters into the boundary current is consistent with an eddy transport mechanism. Our results suggest that light intermediate waters can contribute to overturning as much as waters formed by deeper convection and that the export time scales of both project onto overturning variability. Plain Language Summary The deep ocean can regulate the Earth's climate by storing carbon and heat. At high latitudes, waters are cooled by the atmosphere and sink, but they can only be successfully stored in the deep ocean if they are exported toward the equator. In this study, we analyze new mooring observations in the Irminger Sea to investigate the cooling and export of high‐latitude waters. In addition to the well‐documented waters that are cooled in the center of the Irminger Sea, we find that saltier waters are cooled near the western boundary current. Both of these water types make it into boundary current and are exported. Our observations are consistent with the dynamics of swirling eddy motions. The eddy transport process is more effective for the waters cooled near the boundary current, implying that cooling near boundary currents may be more important for the climate than has been appreciated to date

Prospects for Exoplanet Imaging in Multi-Star Systems with Starshades

We explore the capabilities of a starshade mission to directly image multi-star systems. In addition to the diffracted and scattered light for the on-axis star, a multi-star system features additional starlight leakage from the off-axis star that must also be controlled. A basic option is for additional starshades to block the off- axis stars. An interesting option takes the form of hybrid operation of a starshade in conjunction with an internal starlight suppression. Two hybrid scenarios are considered. One such scenario includes the coronagraph instrument blocking the on-axis star, with the starshade blocking off-axis starlight. Another scenario uses the wavefront control system in the coronagraph instrument and using a recent Super-Nyquist Wavefront Control (SNWC) technique can remove the off-axis stars leakage to enable a region of high-contrast around the on-axis star blocked by the starshade. We present simulation results relevant for the WFIRST telescope

The prediction of fatigue using speech as a biosignal

Automatic systems for estimating operator fatigue have application in safety-critical environments. We develop and evaluate a system to detect fatigue from speech recordings collected from speakers kept awake over a 60-hour period. A binary classification system (fatigued/not-fatigued) based on time spent awake showed good discrimination, with 80 % unweighted accuracy using raw features, and 90 % with speaker-normalized features. We describe the data collection, feature analysis, machine learning and cross-validation used in the study. Results are promising for real-world applications in domains such as aerospace, transportation and mining where operators are in regular verbal communication as part of their normal working activities

Enhancing the emotional and social skills of the youth to promote their wellbeing and positive development: a systematic review of universal school-based randomized controlled trials

Background: The acquisition of social and emotional skills is associated with positive youth development, character education, healthy lifestyle behaviours, reduction in depression and anxiety, conduct disorders, violence, bullying, conflict, and anger. School-based interventions aimed to enhance these skills go beyond a problem-focused approach to embrace a more positive view of health; they could also improve the youth's wellbeing. Aim: To describe the main features and to establish the effectiveness of universal school-based RCTs for children and the youth, aimed to promote their psychosocial wellbeing, positive development, healthy lifestyle behaviours and/or academic performance by improving their emotional and social skills. Methods: Systematic review by searching for relevant papers in PubMed/Medline with the following key words: "mental health" OR "wellbeing" OR "health promotion" OR "emotional learning" OR "social learning" OR "emotional and social learning" OR "positive youth development" OR "life skills" OR "life skills training" AND "school". Interval was set from January 2000 to April 2014. Results: 1,984 papers were identified through the search. Out of them 22 RCTs were included. While most interventions were characterized by a whole-school approach and SAFE practices, few studies only used standardized measures to assess outcomes, or had collected follow-up data after ≥ 6 months. The results of all these trials were examined and discussed. Conclusion: Universal school-based RCTs to enhance emotional and social skills showed controversial findings, due to some methodological issues mainly. Nevertheless they show promising outcomes that are relatively far-reaching for children and youth wellbeing and therefore are important in the real worl