Emergency hospital services utilization in Lleida (Spain): a cross-sectional study of immigrant and Spanish-born populations

Background: The use of emergency hospital services (EHS) has increased steadily in Spain in the last decade while the number of immigrants has increased dramatically. Studies show that immigrants use EHS differently than native-born individuals, and this work investigates demographics, diagnoses and utilization rates of EHS in Lleida (Spain). Methods: Cross-sectional study of all the 96,916 EHS visits by patients 15 to 64 years old, attended during the years 2004 and 2005 in a public teaching hospital. Demographic data, diagnoses of the EHS visits, frequency of hospital admissions, mortality and diagnoses at hospital discharge were obtained. Utilization rates were estimated by group of origin. Poisson regression was used to estimate the rate ratios of being visited in the EHS with respect to the Spanish-born population. Results: Immigrants from low-income countries use EHS services more than the Spanish-born population. Differences in utilization patterns are particularly marked for Maghrebi men and women and sub-Saharan women. Immigrant males are at lower risk of being admitted to the hospital, as compared with Spanish-born males. On the other hand, immigrant women are at higher risk of being admitted. After excluding the visits with gynecologic and obstetric diagnoses, women from sub-Saharan Africa and the Maghreb are still at a higher risk of being admitted than their Spanish-born counterparts. Conclusion: In Lleida (Spain), immigrants use more EHS than the Spanish born population. Future research should indicate whether the same pattern is found in other areas of Spain and whether EHS use is attributable to health needs, barriers to access to the primary care services or similarities in the way immigrants access health care in their countries of origin.

A prospective cohort study of healthcare visits and rehospitalizations after hospital discharge in community-acquired pneumonia

Background and objective: We aimed to identify the frequency of, reasons for and risk factors associated with additional healthcare visits and rehospitalizations (healthcare interactions) by patients with community-acquired pneumonia (CAP) within 30 days of hospital discharge. Methods: Observational analysis of a prospective cohort of adults hospitalized with CAP at a tertiary hospital (2007-2009). Additional healthcare interactions were defined as the visits to a primary care centre or emergency department and hospital readmissions within 30 days of discharge. Results: Of the 934 hospitalized patients with CAP, 282 (34.1%) had additional healthcare interactions within 30 days of hospital discharge: 149 (52.8%) needed an additional visit to their primary care centre and 177 (62.8%) attended the emergency department. Seventy-two (25.5%) patients were readmitted to hospital. The main reasons for additional healthcare interactions were worsening of signs or symptoms of CAP and new or worsening comorbid conditions independent of pneumonia, mainly cardiovascular and pulmonary diseases. The only independent factor associated with visits to primary care centre or emergency department was alcohol abuse (odds ratio [OR] = 1.65; 95% confidence interval [CI]: 1.03-2.64). Prior hospitalization (≤ 90 days) (OR = 2.47; 95% CI: 1.11-5.52) and comorbidities (OR = 3.99; 95% CI: 1.12-14.23) were independently associated with rehospitalization. Conclusions: Additional healthcare visits and rehospitalizations within 30 days of hospital discharge are common in patients with CAP. This is mainly due to a worsening of signs or symptoms of CAP and/or comorbid conditions. These findings may have implications for discharge planning and follow-up of patients with CAP.

A prospective cohort study of healthcare visits and rehospitalizations after hospital discharge in community-acquired pneumonia

Background and objective: We aimed to identify the frequency of, reasons for and risk factors associated with additional healthcare visits and rehospitalizations (healthcare interactions) by patients with community-acquired pneumonia (CAP) within 30 days of hospital discharge. Methods: Observational analysis of a prospective cohort of adults hospitalized with CAP at a tertiary hospital (2007-2009). Additional healthcare interactions were defined as the visits to a primary care centre or emergency department and hospital readmissions within 30 days of discharge. Results: Of the 934 hospitalized patients with CAP, 282 (34.1%) had additional healthcare interactions within 30 days of hospital discharge: 149 (52.8%) needed an additional visit to their primary care centre and 177 (62.8%) attended the emergency department. Seventy-two (25.5%) patients were readmitted to hospital. The main reasons for additional healthcare interactions were worsening of signs or symptoms of CAP and new or worsening comorbid conditions independent of pneumonia, mainly cardiovascular and pulmonary diseases. The only independent factor associated with visits to primary care centre or emergency department was alcohol abuse (odds ratio [OR] = 1.65; 95% confidence interval [CI]: 1.03-2.64). Prior hospitalization (≤ 90 days) (OR = 2.47; 95% CI: 1.11-5.52) and comorbidities (OR = 3.99; 95% CI: 1.12-14.23) were independently associated with rehospitalization. Conclusions: Additional healthcare visits and rehospitalizations within 30 days of hospital discharge are common in patients with CAP. This is mainly due to a worsening of signs or symptoms of CAP and/or comorbid conditions. These findings may have implications for discharge planning and follow-up of patients with CAP.

A prospective cohort study of healthcare visits and rehospitalizations after hospital discharge in community-acquired pneumonia

Background and objective: We aimed to identify the frequency of, reasons for and risk factors associated with additional healthcare visits and rehospitalizations (healthcare interactions) by patients with community-acquired pneumonia (CAP) within 30 days of hospital discharge. Methods: Observational analysis of a prospective cohort of adults hospitalized with CAP at a tertiary hospital (2007-2009). Additional healthcare interactions were defined as the visits to a primary care centre or emergency department and hospital readmissions within 30 days of discharge. Results: Of the 934 hospitalized patients with CAP, 282 (34.1%) had additional healthcare interactions within 30 days of hospital discharge: 149 (52.8%) needed an additional visit to their primary care centre and 177 (62.8%) attended the emergency department. Seventy-two (25.5%) patients were readmitted to hospital. The main reasons for additional healthcare interactions were worsening of signs or symptoms of CAP and new or worsening comorbid conditions independent of pneumonia, mainly cardiovascular and pulmonary diseases. The only independent factor associated with visits to primary care centre or emergency department was alcohol abuse (odds ratio [OR] = 1.65; 95% confidence interval [CI]: 1.03-2.64). Prior hospitalization (≤ 90 days) (OR = 2.47; 95% CI: 1.11-5.52) and comorbidities (OR = 3.99; 95% CI: 1.12-14.23) were independently associated with rehospitalization. Conclusions: Additional healthcare visits and rehospitalizations within 30 days of hospital discharge are common in patients with CAP. This is mainly due to a worsening of signs or symptoms of CAP and/or comorbid conditions. These findings may have implications for discharge planning and follow-up of patients with CAP.

Smith and Rawls share a room

We consider one-to-one matching (roommate) problems in which agents (students) can either be matched as pairs or remain single. The aim of this paper is twofold. First, we review a key result for roommate problems (the ``lonely wolf'' theorem) for which we provide a concise and elementary proof. Second, and related to the title of this paper, we show how the often incompatible concepts of stability (represented by the political economist Adam Smith) and fairness (represented by the political philosopher John Rawls) can be reconciled for roommate problems.

Agent based simulation to optimise emergency departments

Nowadays, many of the health care systems are large and complex environments and quite dynamic, specifically Emergency Departments, EDs. It is opened and working 24 hours per day throughout the year with limited resources, whereas it is overcrowded. Thus, is mandatory to simulate EDs to improve qualitatively and quantitatively their performance. This improvement can be achieved modelling and simulating EDs using Agent-Based Model, ABM and optimising many different staff scenarios. This work optimises the staff configuration of an ED. In order to do optimisation, objective functions to minimise or maximise have to be set. One of those objective functions is to find the best or optimum staff configuration that minimise patient waiting time. The staff configuration comprises: doctors, triage nurses, and admissions, the amount and sort of them. Staff configuration is a combinatorial problem, that can take a lot of time to be solved. HPC is used to run the experiments, and encouraging results were obtained. However, even with the basic ED used in this work the search space is very large, thus, when the problem size increases, it is going to need more resources of processing in order to obtain results in an acceptable time.

Impedance boundary conditions for pseudo-spectral time-domain methods in room acoustics

The pseudo-spectral time-domain (PSTD) method is an alternative time-marching method to classicalleapfrog finite difference schemes in the simulation of wave-like propagating phenomena. It is basedon the fundamentals of the Fourier transform to compute the spatial derivatives of hyperbolic differential equations. Therefore, it results in an isotropic operator that can be implemented in an efficient way for room acoustics simulations. However, one of the first issues to be solved consists on modeling wallabsorption. Unfortunately, there are no references in the technical literature concerning to that problem. In this paper, assuming real and constant locally reacting impedances, several proposals to overcome this problem are presented, validated and compared to analytical solutions in different scenarios.

Impedance boundary conditions for pseudo-spectral time-domain methods in room acoustics

The Pseudo-Spectral Time Domain (PSTD) method is an alternative time-marching method to classical leapfrog finite difference schemes inthe simulation of wave-like propagating phenomena. It is based on the fundamentals of the Fourier transform to compute the spatial derivativesof hyperbolic differential equations. Therefore, it results in an isotropic operator that can be implemented in an efficient way for room acousticssimulations. However, one of the first issues to be solved consists on modeling wall absorption. Unfortunately, there are no references in thetechnical literature concerning to that problem. In this paper, assuming real and constant locally reacting impedances, several proposals toovercome this problem are presented, validated and compared to analytical solutions in different scenarios.

Survival and Sensemaking: Organizational Resilience in a Wall Street Trading Room After 9/11

How do organizations cope with extreme uncertainty? The existing literature is divided on this issue: some argue that organizations deal best with uncertainty in the environment by reproducing it in the organization, whereas others contend that the orga nization should be protected from the environment. In this paper we study the case of a Wall Street investment bank that lost its entire office and trading technology in the terrorist attack of September 11 th. The traders survived, but were forced to relocate to a makeshift trading room in New Jersey. During the six months the traders spent outside New York City, they had to deal with fears and insecurities inside the company as well as outside it: anxiety about additional attacks, questions of professional identity, doubts about the future of the firm, and ambiguities about the future re-location of the trading room. The firm overcame these uncertainties by protecting the traders' identities and their ability to engage in sensemaking. The organization held together through a leadership style that managed ambiguities and created the conditions for new solutions to emerge.

Ecologies of Value in a Wall Street Trading Room

Our task in this paper is to analyze the organization of trading in the era of quantitative finance. To do so, we conduct an ethnography of arbitrage, the trading strategy that best exemplifies finance in the wake of the quantitative revolution. In contrast to value and momentum investing, we argue, arbitrage involves an art of association-the construction of equivalence (comparability) of properties across different assets. In place of essential or relational characteristics, the peculiar valuation that takes place in arbitrage is based on an operation that makes something the measure of something else-associating securities to each other. The process of recognizing opportunities and the practices of making novel associations are shaped by the specific socio-spatial and socio-technical configurations of the trading room. Calculation is distributed across persons and instruments as the trading room organizes interaction among diverse principles of valuation.

Locating emergency services with priority rules: The priority queuing covering location problem

One of the assumptions of the Capacitated Facility Location Problem (CFLP) is thatdemand is known and fixed. Most often, this is not the case when managers take somestrategic decisions such as locating facilities and assigning demand points to thosefacilities. In this paper we consider demand as stochastic and we model each of thefacilities as an independent queue. Stochastic models of manufacturing systems anddeterministic location models are put together in order to obtain a formula for thebacklogging probability at a potential facility location.Several solution techniques have been proposed to solve the CFLP. One of the mostrecently proposed heuristics, a Reactive Greedy Adaptive Search Procedure, isimplemented in order to solve the model formulated. We present some computationalexperiments in order to evaluate the heuristics performance and to illustrate the use ofthis new formulation for the CFLP. The paper finishes with a simple simulationexercise.

Health care provider choice in the case of patient-initiated contacts. An extended version of discrete choice of model demand

This paper analyzes the nature of health care provider choice inthe case of patient-initiated contacts, with special reference toa National Health Service setting, where monetary prices are zeroand general practitioners act as gatekeepers to publicly financedspecialized care. We focus our attention on the factors that mayexplain the continuously increasing use of hospital emergencyvisits as opposed to other provider alternatives. An extendedversion of a discrete choice model of demand for patient-initiatedcontacts is presented, allowing for individual and town residencesize differences in perceived quality (preferences) betweenalternative providers and including travel and waiting time asnon-monetary costs. Results of a nested multinomial logit model ofprovider choice are presented. Individual choice betweenalternatives considers, in a repeated nested structure, self-care,primary care, hospital and clinic emergency services. Welfareimplications and income effects are analyzed by computingcompensating variations, and by simulating the effects of userfees by levels of income. Results indicate that compensatingvariation per visit is higher than the direct marginal cost ofemergency visits, and consequently, emergency visits do not appearas an inefficient alternative even for non-urgent conditions.

Resolving identities: Successive crises in a trading room after 9/11

How do organizations cope with extreme uncertainty? The existing literatureis divided on this issue: some argue that organizations deal best withuncertainty in the environment by reproducing it in the organization, whereasothers contend that the orga nization should be protected from theenvironment. In this paper we study the case of a Wall Street investment bankthat lost its entire office and trading technology in the terrorist attack ofSeptember 11 th. The traders survived, but were forced to relocate to amakeshift trading room in New Jersey. During the six months the traders spentoutside New York City, they had to deal with fears and insecurities insidethe company as well as outside it: anxiety about additional attacks,questions of professional identity, doubts about the future of the firm, andambiguities about the future re-location of the trading room. The firmovercame these uncertainties by protecting the traders identities and theirability to engage in sensemaking. The organization held together through aleadership style that managed ambiguities and created the conditions for newsolutions to emerge.

Locating emergency services with different priorities: The priority queuing covering location problem

Previous covering models for emergency service consider all the calls to be of the sameimportance and impose the same waiting time constraints independently of the service's priority.This type of constraint is clearly inappropriate in many contexts. For example, in urban medicalemergency services, calls that involve danger to human life deserve higher priority over calls formore routine incidents. A realistic model in such a context should allow prioritizing the calls forservice.In this paper a covering model which considers different priority levels is formulated andsolved. The model heritages its formulation from previous research on Maximum CoverageModels and incorporates results from Queuing Theory, in particular Priority Queuing. Theadditional complexity incorporated in the model justifies the use of a heuristic procedure.

How to recognize opportunities: Heterarchical search in a Wall Street trading room

Our task in this paper is to analyze the organization of trading in the era of quantitativefinance. To do so, we conduct an ethnography of arbitrage, the trading strategy that bestexemplifies finance in the wake of the quantitative revolution. In contrast to value andmomentum investing, we argue, arbitrage involves an art of association - the constructionof equivalence (comparability) of properties across different assets. In place of essentialor relationa l characteristics, the peculiar valuation that takes place in arbitrage is based on an operation that makes something the measure of something else - associating securities to each other. The process of recognizing opportunities and the practices of making novel associations are shaped by the specific socio-spatial and socio-technical configurations of the trading room. Calculation is distributed across persons and instruments as the trading room organizes interaction among diverse principles of valuation.