Changes in Emergency Department Care Intensity from 2007-16: Analysis of the National Hospital Ambulatory Medical Care Survey

Introduction: Emergency departments (ED) in the United States (US) have increasingly taken the central role for the expedited diagnosis and treatment of acute episodic illnesses and exacerbations of chronic diseases, allowing outpatient management to be possible for many conditions that traditionally required hospitalization and inpatient care. The goal of this analysis was to examine the changes in ED care intensity in this context through the changes in ED patient population and ED care provided.Methods: We analyzed the National Hospital Ambulatory Medical Care Survey (NHAMCS) from 2007-2016. Incorporating survey design and weight, we calculated the changes in ED patient characteristics and ED care provided between 2007 and 2016. We also calculated changes in the proportion of visits with low-severity illnesses that may be safely managed at alternative settings. Lastly, we compared ED care received and final ED dispositions by calculating adjusted relative risk (aRR) comparing ED visits in 2007 to 2016, using survey weighted multivariable logistic regression.Results: NHAMCS included 35,490 visits in 2007 and 19,467 visits in 2016, representing 117 million and 146 million ED visits, respectively. Between 2007 and 2016, there was an increase in the proportion of ED patients aged 45-64 (21.0% to 23.6%) and 65-74 (5.9% to 7.5%), while visits with low-severity illnesses decreased from 37.3% to 30.4%. There was a substantial increase in the proportion of Medicaid patients (22.2% to 34.0%) with corresponding decline in the privately insured (36.2% to 28.3%) and the uninsured (15.4% to 8.6%) patients. After adjusting for patient and visit characteristics, there was an increase in the utilization of advanced imaging (aRR 1.29; 95% confidence interval [CI], 1.17-1.41), blood tests (aRR 1.16; 95% CI, 1.10-1.22), urinalysis (aRR 1.22; 95% CI, 1.13-1.31), and visits where the patient received four or more medications (aRR 2.17; 95% CI, 1.88-2.46). Lastly, adjusted hospitalization rates declined (aRR 0.74; 95% CI, 0.64-0.84) while adjusted discharge rates increased (aRR 1.06; 95%CI 1.03-1.08). Conclusion: From 2007 to 2016, ED care intensity appears to have increased modestly, including aging of patient population, increased illness severity, and increased resources utilization. The role of increased care intensity in the decline of ED hospitalization rate requires further study

Searching out of Trading Noise: A Study of Intraday Transactions Cost

We attempt to identify in this paper the role of trading noise as a transactions cost to market participant in the sense of Stoll (2000), especially in the presence of trading concentration. Applying the measures of Hu (2006) and Kang and Yeo (2008), we analyze the noise proportion in intraday stock returns and its interaction with investor herding and search cost. Although this noise is high on individual orders and low on institutional orders, its behavior at market open is entirely different from the rest of the day. Noises for small cap stocks, unlike volatilities, are lower than those for large cap stocks. We also found that noise relates positively to trading volume, but inversely to holdings and turnover ratio of institutional investors. Responses from institutional and individuals are quite the opposite. The noise proportion generated by individual order rises with institutional turnover and search cost encountered, while that of institutional order behaves just oppositely. At market open, behaviors of noise from institutional and individual orders just switch mutually, and then switch back afterwards. Also, noise from high-cap stocks is actually more responsive than that from low-cap ones across investors. So trading noise is a specific transactions cost, prominent to only certain investors, at certain time and for certain stocks in the market, rather than a general market friction as argued in Stoll (2000). This transactions cost is inversely related to search costs encountered in trading, which depends on investor, trading hour of day and market capitalization of stocks.Noise, transaction cost, herding, search model, order book

Scalable and cost-effective optical components for biosensing applications

Cost-effectiveness has been a key factor in consumer biophotonics. In this talk, I will discuss two approaches for overall cost reduction. First, I will introduce a highly porous yet monolithic plasmonic nanosurface that features intense and high-density hot spots, large surface area, and high structural integrity and reproducibility. The fabrication process of this nanosurface is of low-cost and highly scalable. Using localized surface plasmon resonance (LSPR) and coupling modes, enhanced light-matter interactions near the nanosurface can be realized. The surface enhancement results in stronger signal which reduces the burden on high-end optical detection systems. We have applied them to several analytical Chem/Biosensing platforms for a range of sensing targets by various spectroscopic and imaging techniques. Nanoplasmonic sensors appear to provide potential solutions in a range of applications from precision medicine to point-of-care diagnostics and wearable technologies. In the second approach, we have developed an “inkjet printing” process for making polymer lenses which enable high quality microscopic imaging using smartphones – High performance microscopy of nanoscale objects and molecular species can be carried out on $10 phones. Finally, I will discuss the synergy of plasmonic enhancement and smartphone microscopy in the context of consumer biophotonics

Three essays on agglomeration, strategic orientation, and organizational form

This dissertation consists of three essays, trying to fill a gap in the literature by exploring the interaction of agglomeration, ownership structure, and strategic orientation. Much research has been focused on each perspective of issues, but little work has been done on the outcomes from the interaction. The first essay focuses on how the effect of franchising influences the performance of hotel segments across all identifiable hotel chain locations in the United States. This essay analyzes the effect of franchising in the aggregate, controlling for brand quality segments, or service levels, as well as each individual quality tier. In addition, this essay examines the effect of franchising both with and without controls for the endogeneity of the franchise treatment decision. First, the findings indicate that franchised-ownership is associated with higher performance outcomes among hotels both with and without controlling the endogenous selection. Second, the results imply that the effects of franchising and multi-unit franchising have differential benefits based on the product quality attributes of the establishments, and suggest that previous studies examining franchising way have overlooked these differences. The second essay presents the joint choices of geographic location and product positioning in the Texas lodging industry. The literature on the two-dimension Hotelling model concludes that firms choose to maximally differentiate on the dominant characteristic and minimally differentiate on the dominated characteristic. I argue that, assuming the geographic location is the dominant characteristic and the product positioning is the dominated characteristic, the model implies that multi-unit owners will structure their portfolios of establishments to be geographically differentiated while choosing less differentiated brands. Alternatively, I argue that, if the geographic location is the dominated characteristic and the product positioning is the dominant characteristic, the model implies that multi-unit owners will locate their establishments near one another in a geographic space while choosing highly differentiated brands. The empirical findings indicate a max-min (min-max) equilibrium, which provides insights into the strategic motivations of multi-unit operators and the relative dominance of place versus market position in those decisions. The third essay analyzes how product market strategy and ownership structure influence the evolution of the cluster. Using the data from the Texas Comptroller of Public Accounts from 2010 to 2016, this study focuses on how the joint effects of product market strategy and ownership structure shape the lodging industry dynamics and eventually the spatial distribution of hotels. The literature on agglomeration claims that the agglomeration effect is heterogeneous among hotels and this effect is based on product heterogeneity between entrants and incumbents nearby. In addition, the choice of the ownership structure of entrants might substantially change the competitive environment of the market. This research proposes that multi-unit owners who operate a bundle of product portfolios can obtain more benefits but neutralize more threats from agglomeration. The results show that the multi-unit owner will establish a new high-end hotel in the market characterized by high counts of low end hotels if one of the incumbents belongs to the multi-unit owner. Moreover, the findings also show that multi-unit owners who operate multiple cross-tier/same-chain hotels will neutralize the negative externality from agglomeration. The results imply that the owner of high-end hotels may find it beneficial to control nearby incumbents.Includes bibliographical reference

Taiwanese planning law : a historical review and comparison with Hong Kong

This thesis compares the evolution of urban planning systems and related laws that operate within Taiwan and Hong Kong. By conducting a historic review, this thesis studies how planning laws and urban plans have been made, shaped and written, as well as their effects on spatial development. Borrowing from Patrick McAuslan’s “Ideologies of planning law” concept, this thesis observes that planning laws are compromised products of domestic and foreign socio-political forces beyond planners’ control, with three competing ideologies (private property, public interest and public participation) dominating at various stages of the respective planning systems. On the surface, the private property and public interest ideologies appear to contradict each other. However, historically examining the implementation of urban planning by the developmentalist states of Taiwan and Hong Kong reveals that both ideologies have and still do serve the interests of certain power blocs and property developers. While the public interest ideology was upheld, the racial factor and sanitation syndrome present in the urban regularisation resulted in spatial apartheid and the ideology serving the interests of the colonial forces occupying each territory; while the private property ideology was upheld, the betterment of certain people’s property right was built on less privileged people’s losses. Researching the interaction between building violations and informal housing concludes that laws can be arbitrary and fluid in practice, with the line of legality having to be drawn and redrawn. With disadvantaged people living in informal housing, building violations eased government responsibility in relation to the burden on housing and intervening in the property market. While the first two ideologies sustain the existing capitalist system with an emphasis on a functional property market, the third ideology has the potential to become an oppositional ideology to the status quo if planners acknowledge that planning law is not apolitical but an arena for challenging the existing administration

Parallel Algorithms for Single-Layer Channel Routing

We provide efficient parallel algorithms for the minimum separation, offset range, and optimal offset problems for single-layer channel routing. We consider all the variations of these problems that are known to have linear- time sequential solutions rather than limiting attention to the river-routing context, where single-sided connections are disallowed. For the minimum separation problem, we obtain O(lgN) time on a CREW PRAM or O(lgN / lglgN) time on a (common) CRCW PRAM, both with optimal work (processor- time product) of O(N), where N is the number of terminals. For the offset range problem, we obtain the same time and processor bounds as long as only one side of the channel contains single-sided nets. For the optimal offset problem with single-sided nets on one side of the channel, we obtain time O(lgN lglgN) on a CREW PRAM or O(lgN / lglgN) time on a CRCW PRAM with O(N lglgN) work. Not only does this improve on previous results for river routing, but we can obtain an even better time of O((lglgN)^2) on the CRCW PRAM in the river routing context. In addition, wherever our results allow a channel boundary to contain single-sided nets, the results also apply when that boundary is ragged and N incorporates the number of bendpoints