Stressors Experienced By Emergency Department Registered Nurses At The Bedside: A Phenomenological Study

The Emergency Department (ED) as a workplace for the Registered Nurse (RN) is a stressful environment. Reasons are thought to include interactions with other members of the interdisciplinary team as well as the situations associated with the environment of the ED such as trauma, death, sadness, joy and the general unpredictability of each moment. Studies have documented general health care workplace stress and its influence on staff, but a very limited number of studies have concentrated on the ED. No widely published studies have identified stressors from the perspective of the ED RN. This dissertation is an interpretive phenomenological study that seeks to understand the experience of being an ED RN through the exploration of the perceptions of stress as lived by individuals who practice their art and science in this unique setting. Materials for evaluation and thematic identification were obtained through personal interviews of practicing nurses. The stories told by the participants communicated what each individual found to be negatively stressful as well as what each found to be positively stressful. Conclusions based on the findings of this work suggest a need for the ED RN to be able to depend on the presence of several factors in order to be able to function with as little distress as possible. The optimal ED environment for the RN is posited to be supportive of the individual goals of the RN, provide adequate resources and foster a communicative interdisciplinary environment. Recommendations are made to improve resource management and interdisciplinary relation

Statistical and machine learning models for critical infrastructure resilience

This thesis presents a data-driven approach to improving predictions of critical infrastructure behaviors. In our first approach, we explore novel data sources and time series modeling techniques to model disaster impacts on power systems through the case study of Hurricane Sandy as it impacted the state of New York. We find a correlation between Twitter data and load forecast errors, suggesting that Twitter data may provide value towards predicting impacts of disasters on infrastructure systems. Based on these findings, we then develop time series forecasting methods to predict the NYISO power system behaviors at the zonal level, utilizing Twitter and load forecast data as model inputs. In our second approach, we develop a novel, graph-based formulation of the British rail network to model the nonlinear cascading delays on the rail network. Using this formulation, we then develop machine learning approaches to predict delays in the rail network. Through experiments on real-world rail data, we find that the selected architecture provides more accurate predictions than other models due to its ability to capture both spatial and temporal dimensions of the data

Mechanical transients initiated by ramp stretch and release to P0 in frog muscle fibers

Single fibers from the tibialis muscle of Rana temporaria were subjected to ramp stretches during tetanic stimulation at a sarcomere length of ~2 \u3bcm. Immediately after the stretch, or after different time delays, the active fiber was released against a constant force equal to the isometric force (P0) exerted immediately before the stretch. Four phases were detected after release: 1) an elastic recoil of the fiber's undamped elements, 2) a transient rapid shortening, 3) a marked reduction in the velocity of shortening (often to 0), and 4) an apparently steady shortening (sometimes absent). Increasing the amplitude of the stretch from ~2 to 10% of the fiber rest length led to an increase in phase 2 shortening from ~5 to 10 nm per half-sarcomere. Phase 2 shortening increased further (up to 14 nm per half-sarcomere) if a time interval of 5-10 ms was left between the end of large ramp stretches and release to P0. After 50- to 100-ms time intervals, shortening occurred in two steps of ~5 nm per half-sarcomere each. These findings suggest that phase 2 is due to charging, during and after the stretch, of a damped element, which can then shorten against P0 in at least two steps of ~5 nm/half sarcomere each

The bounce of the body in hopping, running and trotting: different machines with the same motor

The bouncing mechanism of human running is characterized by a shorter duration of the brake after ‘landing’ compared with a longer duration of the push before ‘takeoff’. This landing–takeoff asymmetry has been thought to be a consequence of the force–velocity relation of the muscle, resulting in a greater force exerted during stretching after landing and a lower force developed during shortening before takeoff. However, the asymmetric lever system of the human foot during stance may also be the cause. Here, we measure the landing–takeoff asymmetry in bouncing steps of running, hopping and trotting animals using diverse lever systems. We find that the duration of the push exceeds that of the brake in all the animals, indicating that the different lever systems comply with the basic property of muscle to resist stretching with a force greater than that developed during shortening. In addition, results show both the landing–takeoff asymmetry and the mass-specific vertical stiffness to be greater in small animals than in large animals. We suggest that the landing–takeoff asymmetry is an index of a lack of elasticity, which increases with increasing the role of muscle relative to that of tendon within muscle–tendon units

Sensitivity of Species Habitat-Relationship Model Performance to Factors of Scale

Researchers have come to different conclusions about the usefulness of habitat-relationship models for predicting species presence or absence. This difference frequently stems from a failure to recognize the effects of spatial scales at which the models are applied. We examined the effects of model complexity, spatial data resolution, and scale of application on the performance of bird habitat relationship (BHR) models on the Craig Mountain Wildlife Management Area and on the Idaho portion of the U.S. Forest Service\u27s Northern Region. We constructed and tested BHR models for 60 bird species detected on the study areas. The models varied by three levels of complexity (amount of habitat information) and three spatial data resolutions (0.09 ha, 4 ha, 10 ha). We tested these models at two levels of analysis: the site level (a homogeneous area \u3c0.5 ha) and cover-type level (an aggregation of many similar sites of a similar land-cover type), using correspondence between model predictions and species detections to calculate kappa coefficients of agreement. Model performance initially increased as models became more complex until a point was reached where omission errors increased at a rate greater than the rate at which commission errors were decreasing. Heterogeneity of the study areas appeared to influence the effect of model complexity. Changes in model complexity resulted in a greater decrease in commission error than increase in omission error. The effect of spatial data resolution on the performance of BHR models was influenced by the variability of the study area. BHR models performed better at cover-type levels of analysis than at the site level for both study areas. Correct-presence estimates (1 − minus percentage omission error) decreased slightly as number of species detections increased on each study area. Correct-absence estimates (1 − percentage commission error) increased as number of species detections increased on each study area. This suggests that a large number of detections may be necessary to achieve reliable estimates of model accuracy

Two explanations for the compliant running paradox: reduced work of bouncing viscera and increased stability in uneven terrain

Economy is a central principle for understanding animal locomotion. Yet, compared with theoretical predictions concerning economy, animals run with compliant legs that are energetically costly. Here, we address this apparent paradox, highlighting two factors that predict benefits for compliant gaits: (i) minimizing cost of work associated with bouncing viscera; and (ii) leg control for robust stability in uneven terrain. We show that consideration of the effects of bouncing viscera predicts an energetic optimum for relatively compliant legs. To compare stability in uneven terrain, we introduce the normalized maximum drop (NMD), a measure based on simple kinematics, which predicts that compliant legs allow negotiation of relatively larger terrain perturbations without failure. Our model also suggests an inherent trade-off in control of leg retraction velocity (ω) for stability: low ω allows higher NMD, reducing fall risk, whereas high ω minimizes peak forces with terrain drops, reducing injury risk. Optimization for one of these factors explicitly limits the other; however, compliant legs relax this trade-off, allowing greater stability by both measures. Our models suggest compromises in leg control for economy and stability that might explain why animals run with compliant legs

Economic insecurities and patient-reported outcomes in patients with systemic lupus erythematosus in the USA: a cross-sectional analysis of data from the California Lupus Epidemiology Study

Background Social determinants of health are consistently associated with systemic lupus erythematosus (SLE) outcomes. However, social determinants of health are typically measured with conventional socioeconomic status factors such as income or education. We assessed the association of economic insecurities (ie, food, housing, health care, and financial insecurity) with patient-reported outcomes in a cohort of patients with SLE.Methods In this cross-sectional analysis, data were derived from the California Lupus Epidemiology Study based in the San Francisco Bay Area, CA, USA. Participants were recruited between Feb 25, 2015, and Jan 10, 2018, from rheumatology clinics. Inclusion criteria were Bay Area residency; oral fluency in English, Spanish, Cantonese, or Mandarin; 18 years or older; ability to provide informed consent; and a physician confirmed SLE diagnosis. Food, housing, health care, and financial economic insecurities were assessed by validated screening tools. Patient-reported outcomes were obtained using PROMIS, Quality of Life in Neurological Disorders (known as Neuro-QoL) Cognitive Function short form, Patient Health Questionnaire (PHQ)-8, and General Anxiety Disorder (GAD)-7 instruments. Poverty was defined as household income of 125% or less of the federal poverty limit. Lower education was defined as less than college-graduate education. The association of economic insecurities with patient-reported outcomes was assessed by multivariable linear regression models adjusting for demographics, SLE disease characteristics, and comorbidities. We tested for interactions of insecurities with poverty and education.Findings The final cohort included 252 participants. Mean age was 49·7 (SD 13·4) years, 228 (90%) of 252 were women and 24 (10%) were men. 80 (32%) individuals self-identified as Asian, 26 (10%) as Black, 101 (40%) as White, eight (3%) as mixed race, and 37 (15%) as other race; 59 (23%) self-identified as Hispanic. 135 (54%) individuals had at least one insecurity. Insecurities were highly prevalent, and more common in those with poverty and lower education. Adjusted multivariate analyses revealed that participants with any insecurity had significantly worse scores across all measured patient-reported outcomes. For physical function, no insecurity had an adjusted mean score of 48·9 (95% CI 47·5–50·3) and any insecurity had 45·7 (44·3–47·0; p=0·0017). For pain interference, no insecurity was 52·0 (50·5–53·5) and any insecurity was 54·4 (53·0–55·8; p=0·031). For fatigue, no insecurity was 50·5 (48·8–52·3) and any insecurity was 54·9 (53·3–56·5; p=0·0005). For sleep disturbance, no insecurity was 49·9 (48·3–51·6) and any insecurity was 52·9 (51·4–54·5; p=0·012). For cognitive function, no insecurity was 49·3 (47·7–50·9) and any insecurity was 45·6 (44·1–47·0; p=0·0011). For PHQ-8, no insecurity was 4·4 (3·6–5·1) and any insecurity was 6·1 (5·4–6·8; p=0·0013). For GAD-7, no insecurity was 3·3 (2·6–4·1) and any insecurity was 5·2 (4·5–5·9; p=0·0008). Individuals with more insecurities had worse patientreported outcomes. There were no statistically significant interactions between insecurities and poverty or education. Interpretation Having any economic insecurity was associated with worse outcomes for people with SLE regardless of poverty or education. The findings of this study provide insight into the relationship between economic insecurities and SLE outcomes and underscore the need to assess whether interventions that directly address these insecurities can reduce health disparities in SL