Application of Systems Engineering Science to the Healthcare Environment

This Doctoral dissertation consists of a research portfolio examining the application of systems engineering techniques to the healthcare environment. The portfolio consists of three final publishable articles submitted to meet the program requirements for the, Doctor of Philosophy in Nursing degree from the University of San Diego, Hahn school of Nursing and Health Sciences. Article one is titled; Use of a bed projection tool to predict ICU bed needs. This article describes the dissertation research study in which a bed projection tool was piloted on an ICU unit to determine the tool\u27s ability to predict inpatient bed requirements. Article 2 is titled; Reducing Disruptive Communication in the Health Care Setting: Use of the Crew Resource Model (CRM). Crew resource is a human factor-engineering model that creates uniform team roles and communication structure. This article advocates the use of this model to assist in dealing with disruptive behaviors by healthcare team professionals. The article advocates the use of the CRM model for meeting the Joint Commission on Hospital Accreditation requirement for organization\u27s in which a plan is implemented for dealing with disruptive communication in the health care environment (by health care team professionals). Article 3 is titled; Application of systems engineering to the hospital environment; has the time for a Nurse Engineer role arrived? This article describes the evolution of systems engineering as a discipline and its historical application. The article stresses the need for Nurses to acquire an engineering skill set in order to participate in the redesign of clinical health systems, which will ensure efficiency and patient safety

Change Agent Impact on Pain Management Experience through Lavender Aromatherapy: Evidence-Based Practice Project

Inadequately controlled acute pain is a problem for hospitalized patients. Non-pharmacological pain management interventions (NPPMIs) are recommended but underutilized. Nurse-directed lavender aromatherapy is a feasible and effective NPPMI. Patients at a community hospital, including its surgical-orthopedic unit, reported lower patient pain management experience scores than the average score of Magnet Recognition status hospitals. The community hospital planned to improve pain management by implementing nurse-directed lavender aromatherapy. The purpose of this evidence-based practice project was to fortify the hospital’s nurse-directed lavender aromatherapy implementation with change agents. A logic model guided implementation. Project aims were to increase the surgical-orthopedic unit’s pain management experience scores and to offer nurse-directed lavender aromatherapy to all appropriate patients by close of the project. Change agents included a Doctor of Nursing Practice student and nurse pain champions. Interventions included Doctor of Nursing Practice student-led: (a) surgical-orthopedic unit Lunch & Learn presentations and Rounding for Results sessions and (b) implementation discussions with nurse pain champions from four units, including the surgical-orthopedic unit. Because of these interventions, surgical-orthopedic unit patient pain experience scores increased from 43rd percentile to 78th percentile. In five of six project weeks, all appropriate surgical-orthopedic unit patients were offered nurse-directed lavender aromatherapy. Adoption of the practice change was successful, but slower than anticipated because of slow adoption by the nurses. Nurse leaders responded to this slow adoption by adding additional change agent rounds. Logic model development and change agents are effective strategies for NPPMI implementation

Revealing Historic Invasion Patterns and Potential Invasion Sites for Two Non-Native Plant Species

The historical spatio-temporal distribution of invasive species is rarely documented, hampering efforts to understand invasion dynamics, especially at regional scales. Reconstructing historical invasions through use of herbarium records combined with spatial trend analysis and modeling can elucidate spreading patterns and identify susceptible habitats before invasion occurs. Two perennial species were chosen to contrast historic and potential phytogeographies: Japanese knotweed (Polygonum cuspidatum), introduced intentionally across the US; and mugwort (Artemisia vulgaris), introduced largely accidentally to coastal areas. Spatial analysis revealed that early in the invasion, both species have a stochastic distribution across the contiguous US, but east of the 90th meridian, which approximates the Mississippi River, quickly spread to adjacent counties in subsequent decades. In contrast, in locations west of the 90th meridian, many populations never spread outside the founding county, probably a result of encountering unfavorable environmental conditions. Regression analysis using variables categorized as environmental or anthropogenic accounted for 24% (Japanese knotweed) and 30% (mugwort) of the variation in the current distribution of each species. Results show very few counties with high habitat suitability (≥80%) remain un-invaded (5 for Japanese knotweed and 6 for mugwort), suggesting these perennials are reaching the limits of large-scale expansion. Despite differences in initial introduction loci and pathways, Japanese knotweed and mugwort demonstrate similar historic patterns of spread and show declining rates of regional expansion. Invasion mitigation efforts should be concentrated on areas identified as highly susceptible that border invaded regions, as both species demonstrate secondary expansion from introduction loci

The Higgs as a Probe of Supersymmetric Extra Sectors

We present a general method for calculating the leading contributions to h -> gg and h -> gamma gamma in models where the Higgs weakly mixes with a nearly supersymmetric extra sector. Such mixing terms can play an important role in raising the Higgs mass relative to the value expected in the MSSM. Our method applies even when the extra sector is strongly coupled, and moreover does not require a microscopic Lagrangian description. Using constraints from holomorphy we fix the leading parametric form of the contributions to these Higgs processes, including the Higgs mixing angle dependence, up to an overall coefficient. Moreover, when the Higgs is the sole source of mass for a superconformal sector, we show that even this coefficient is often calculable. For appropriate mixing angles, the contribution of the extra states to h -> gg and h -> gamma gamma can vanish. We also discuss how current experimental limits already lead to non-trivial constraints on such models. Finally, we provide examples of extra sectors which satisfy the requirements necessary to use the holomorphic approximation.Comment: v4: 34 pages, 2 figures, typo corrected and clarification adde

Invasion speeds for structured populations in fluctuating environments

We live in a time where climate models predict future increases in environmental variability and biological invasions are becoming increasingly frequent. A key to developing effective responses to biological invasions in increasingly variable environments will be estimates of their rates of spatial spread and the associated uncertainty of these estimates. Using stochastic, stage-structured, integro-difference equation models, we show analytically that invasion speeds are asymptotically normally distributed with a variance that decreases in time. We apply our methods to a simple juvenile-adult model with stochastic variation in reproduction and an illustrative example with published data for the perennial herb, \emph{Calathea ovandensis}. These examples buttressed by additional analysis reveal that increased variability in vital rates simultaneously slow down invasions yet generate greater uncertainty about rates of spatial spread. Moreover, while temporal autocorrelations in vital rates inflate variability in invasion speeds, the effect of these autocorrelations on the average invasion speed can be positive or negative depending on life history traits and how well vital rates ``remember'' the past

Phylogenetic structure and host abundance drive disease pressure in communities

Pathogens play an important part in shaping the structure and dynamics of natural communities, because species are not affected by them equally. A shared goal of ecology and epidemiology is to predict when a species is most vulnerable to disease. A leading hypothesis asserts that the impact of disease should increase with host abundance, producing a ‘rare-species advantage. However, the impact of a pathogen may be decoupled from host abundance, because most pathogens infect more than one species, leading to pathogen spillover onto closely related species. Here we show that the phylogenetic and ecological structure of the surrounding community can be important predictors of disease pressure. We found that the amount of tissue lost to disease increased with the relative abundance of a species across a grassland plant community, and that this rare-species advantage had an additional phylogenetic component: disease pressure was stronger on species with many close relatives. We used a global model of pathogen sharing as a function of relatedness between hosts, which provided a robust predictor of relative disease pressure at the local scale. In our grassland, the total amount of disease was most accurately explained not by the abundance of the focal host alone, but by the abundance of all species in the community weighted by their phylogenetic distance to the host. Furthermore, the model strongly predicted observed disease pressure for 44 novel host species we introduced experimentally to our study site, providing evidence for a mechanism to explain why phylogenetically rare species are more likely to become invasive when introduced. Our results demonstrate how the phylogenetic and ecological structure of communities can have a key role in disease dynamics, with implications for the maintenance of biodiversity, biotic resistance against introduced weeds, and the success of managed plants in agriculture and forestry

Effects of climate and snow depth on Bromus tectorum population dynamics at high elevation

Invasive plants are thought to be especially capable of range shifts or expansion in response to climate change due to high dispersal and colonization abilities. Although highly invasive throughout the Intermountain West, the presence and impact of the grass Bromus tectorum has been limited at higher elevations in the eastern Sierra Nevada, potentially due to extreme wintertime conditions. However, climate models project an upward elevational shift of climate regimes in the Sierra Nevada that could favor B. tectorum expansion. This research specifically examined the effects of experimental snow depth manipulations and interannual climate variability over 5 years on B. tectorum populations at high elevation (2,175 m). Experimentally-increased snow depth had an effect on phenology and biomass, but no effect on individual fecundity. Instead an experimentally-increased snowpack inhibited population growth in 1 year by reducing seedling emergence and early survival. A similar negative effect of increased snow was observed 2 years later. However, a strong negative effect on B. tectorum was also associated with a naturally low-snow winter, when seedling emergence was reduced by 86%. Across 5 years, winters with greater snow cover and a slower accumulation of degree-days coincided with higher B. tectorum seedling density and population growth. Thus, we observed negative effects associated with both experimentally-increased and naturally-decreased snowpacks. It is likely that the effect of snow at high elevation is nonlinear and differs from lower elevations where wintertime germination can be favorable. Additionally, we observed a doubling of population size in 1 year, which is alarming at this elevation