bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reverse Auctions with Multiple Reinforcement Learning Agents*
Authors: Bandyopadhyay Subhajyoti , Rees Jackie , Barron John M. 
Published: March 2008

ABSTRACTReverse auctions in business‐to‐business (B2B) exchanges provide numerous benefits to participants. Arguably the most notable benefit is that of lowered prices driven by increased competition in such auctions. The competition between sellers in reverse auctions has been analyzed using a game‐theoretic framework and equilibria have been established for several scenarios. One finding of note is that, in a setting in which sellers can meet total demand with the highest‐bidding seller being able to sell only a fraction of the total capacity, the sellers resort to a mixed‐strategy equilibrium. Although price randomization in industrial bidding is an accepted norm, one might argue that in reality managers do not utilize advanced game theory calculations in placing bids. More likely, managers adopt simple learning strategies. In this situation, it remains an open question as to whether the bid prices converge to the theoretical equilibrium over time. To address this question, we model reverse‐auction bidding behavior by artificial agents as both two‐player and n‐player games in a simulation environment. The agents begin the game with a minimal understanding of the environment but over time analyze wins and losses for use in determining future bids. To test for convergence, the agents explore the price space and exploit prices where profits are higher, given varying cost and capacity scenarios. In the two‐player case, the agents do indeed converge toward the theoretical equilibrium. The n‐player case provides results that reinforce our understanding of the theoretical equilibria. These results are promising enough to further consider the use of artificial learning mechanisms in reverse auctions and other electronic market transactions, especially as more sophisticated mechanisms are developed to tackle real‐life complexities. We also develop the analytical results when one agent does not behave strategically while the other agent does and show that our simulations for this environment also result in convergence toward the theoretical equilibrium. Because the nature of the best response in the new setting is very different (pure strategy as opposed to mixed), it indicates the robustness of the devised algorithm. The use of artificial agents can also overcome the limitations in rationality demonstrated by human managers. The results thus have interesting implications for designing artificial agents in automating bid responses for large numbers of bids where human intervention might not always be possible.
Determinants of Interoutsourcing: An Analytical Approach
Authors: Jiang Bin , Talluri Srinivas , Calantone Roger 
Published: March 2008

ABSTRACTInteroutsourcing is a round‐way process in which the vendor is its customer's customer and the customer is its vendor's vendor. While interoutsourcing is emerging as a prominent outsourcing strategy in many industries, there are no rigorous analytical studies focusing on this mechanism. In this article, we analytically demonstrate the efficacy of interoutsourcing by comparing it with normal outsourcing. Our results show that, compared with normal outsourcing, interoutsourcing acts as a self‐enforcer of vendor firms' behaviors toward increasing outsourcing service value. However, in situations where there is a mismatch of outsourcing activities, a high degree of incentive that is based on outsourcing service value, and a high cost of capital, interoutsourcing is not preferred to normal outsourcing. We discuss these results in detail and provide managerial implications for firms involved in interoutsourcing decisions.
Search for Alternatives and Collaboration with Incumbents: Two‐Sided Sourcing Behavior in Business Markets*
Authors: Kim Stephen Keysuk , Yamada Tetsuya , Kim Hyunchul 
Published: March 2008

ABSTRACTSourcing strategies in business markets have been considered separately and the practice of two‐sided sourcing behavior—engaging in search for alternative suppliers and collaboration with an incumbent supplier—has not been examined. To fill that gap, we first identify boundary conditions under which the poor performance of an incumbent supplier intensifies an original equipment manufacturer's (OEM) search and collaboration. Then, we examine how an OEM's two‐sided sourcing behavior influences one of the critical elements of sourcing performance: the responsiveness of the incumbent supplier. Our proposed hypotheses were tested with data from a national survey of 539 OEM purchasing managers in the Japanese electronics industry. The analysis results indicate three main findings. First, two environmental conditions—pace of technological change and volume uncertainty—have contrasting influences on the link between incumbent supplier performance and an OEM's search and collaboration. While uncertainty from the upstream channel (pace of technological change) enhances an OEM's search and collaboration, uncertainty from the downstream channel (volume uncertainty) lowers an OEM's search and collaboration. Second, an OEM's dependence on its incumbent supplier has differential effects: an OEM reduces search as its dependence on incumbent supplier increases, while it enhances collaboration as its dependence on incumbent supplier increases. Third, while search alone has a negative effect on responsiveness of an incumbent supplier, engaging in two‐sided sourcing behavior (i.e., combining search with collaboration) has a positive effect on responsiveness of the incumbent supplier.
A Rewarming Maneuver Demonstrates the Contribution of Blood Flow to Electrode Cooling During Internally Irrigated RF Ablation
Authors: COOPER JOSHUA M. , SAPP JOHN L. , ROBINSON DAVID , EPSTEIN LAURENCE M. , STEVENSON WILLIAM G. 
Published: March 2008

Introduction:Titration of radiofrequency (RF) ablation energy to avoid steam pops while maximizing lesion size is difficult because of disparities between electrode and tissue temperature. We hypothesized that the variable contribution of local blood flow to electrode cooling contributes to electrode‐tissue temperature disparity, even with an irrigated RF catheter. Methods and Results: Forty RF lesions were made in the atria of live swine with an internally irrigated cooled RF catheter. Prior to RF delivery, the catheter tip was cooled and then allowed to rewarm to body temperature by stopping irrigant flow. The rewarming time (RT) was noted. The catheter was again cooled and RF energy delivered, with power titrated to achieve electrode temperature of 40°C, which was previously defined as the approximate upper limit of safety. Lesion formation and steam pops were observed with intracardiac echocardiography. The RT ranged from 10 to 47 seconds. Nine steam pops were seen. The mean RT for lesions with pops was faster than those without (20 vs. 33 seconds, P = 0.003). The 20 lesions with faster RT required more power to achieve target temperature than the 20 lesions with slower RT (P = 0.01). Eight of nine steam pops occurred in the group with faster RT. Conclusions: RT quantifies convective heating by blood prior to RF. Faster RT predicts greater cooling by blood during irrigated RF, a greater power requirement to reach target electrode temperature, and a higher risk of steam pops during fixed‐temperature ablation. RT therefore can demonstrate the variation in blood cooling with each lesion and can be used to tailor energy delivery to maximize efficacy and safety.
Temporal Stability of the Location of the Esophagus in Patients Undergoing a Repeat Left Atrial Ablation Procedure for Atrial Fibrillation or Flutter
Authors: KENNEDY ROBERT , GOOD ERIC , ORAL HAKAN , HUETHER ELIZABETH , BOGUN FRANK , PELOSI FRANK , MORADY FRED , CHUGH AMAN 
Published: March 2008

Background:
The esophagus may be mobile during a left atrial (LA) ablation procedure for atrial fibrillation (AF).
Objective:
The goal of the study was to determine whether the location of the esophagus is stable in patients undergoing a repeat LA ablation procedure.
Methods:
Forty‐two patients underwent repeat LA ablation a mean of 7 ± 2 months after the initial procedure. Cinefluoroscopic images of the esophagus during a barium swallow were recorded and the course of the esophagus was tagged on the 3D map. The position of the esophagus at the index and repeat procedure were compared.
Results:
At the index procedure, the esophagus was located near the left pulmonary veins (PVs) in 20 (48%), right PVs in 13 (31%), and at the mid LA in 9 (21%) patients. During the repeat procedure, the esophagus was found to be near the left PVs in 22 (52%), right PVs in 11 (26%), and at the mid LA in 9 patients (21%). In 35 of the 42 patients (83%), there was no change in the esophageal location, and in the remaining seven patients (17%), its position had shifted by ≥1 cm (range 1.0–4.0 cm).
Conclusions:
In more than 80% of patients presenting for a repeat LA ablation procedure, the esophagus is in the same position relative to the PVs as during the initial procedure. Therefore, if radiofrequency ablation at a particular location was limited by the position of the esophagus, safe ablation at that site is unlikely to be feasible during a repeat procedure.
Real‐Time Three‐Dimensional Echocardiography Permits Quantification of Left Ventricular Mechanical Dyssynchrony and Predicts Acute Response to Cardiac Resynchronization Therapy
Authors: MARSAN NINA AJMONE , BLEEKER GABE B. , YPENBURG CLAUDIA , GHIO STEFANO , VAN DE VEIRE NICO R. , HOLMAN EDUARD R. , VAN DER WALL ERNST E. , TAVAZZI L. , SCHALIJ MARTIN J. , BAX JEROEN J. 
Published: March 2008

Objective: To evaluate the value of real‐time three‐dimensional echocardiography (RT3DE) to predict acute response to cardiac resynchronization therapy (CRT). Methods: Sixty consecutive heart failure patients scheduled for CRT were included. RT3DE was performed before and within 48 hours after pacemaker implantation to calculate both left ventricular (LV) volumes and LV dyssynchrony. LV dyssynchrony was defined as the standard deviation of the time taken to reach the minimum systolic volume for 16 LV segments (referred to as the systolic dyssynchrony index, SDI). Patients were subsequently divided into acute responders or nonresponders, based on a reduction ≥ 15% in LV end‐systolic volume immediately after CRT. Results: Four patients (7%) were excluded from further analysis because of either suboptimal apical acquisitions or significant translation artifacts. Out of the remaining 56 patients, 35 patients (63%) were classified as acute responders. Baseline characteristics were similar between responders and nonresponders, except for the SDI, which was larger in responders. Moreover, responders demonstrated a significant reduction of SDI immediately after CRT (from 9.7 ± 4.1% to 3.6 ± 1.8%, P < 0.0001), whereas SDI did not change in nonresponders (3.4 ± 1.8% vs 3.1 ± 1.1%, NS). ROC curve analysis revealed that a cut‐off value for SDI of 5.6% yielded a sensitivity of 88% with a specificity of 86% to predict acute echocardiographic response to CRT (AUC 0.96). Conclusion: RT3DE is highly predictive for acute response to CRT (sensitivity 88% and specificity 86%). In addition, RT3DE allows assessment of changes in LV volumes and LV ejection fraction before and after CRT implantation.
Prevalence and Characteristics of Continuous Electrical Activity in Patients with Paroxysmal and Persistent Atrial Fibrillation
Authors: TADA HIROSHI , YOSHIDA KENTARO , CHUGH AMAN , BOONYAPISIT WARANGKNA , CRAWFORD THOMAS , SARRAZIN JEAN‐FRANCOIS , KUHNE MICHAEL , CHALFOUN NAGIB , WELLS DARRYL , DEY SUJOYA , VEERAREDDY SRIKAR , BILLAKANTY SREE , WONG WAI SHUN , KALRA DINESH , KFAHAGI AYMAN , GOOD ERIC , JONGNARANGSIN KRIT , PELOSI FRANK , BOGUN FRANK , MORADY FRED , ORAL HAKAN 
Published: March 2008

Background:
Complex fractionated atrial electrograms (CFAEs) may play a role in the genesis of atrial fibrillation (AF). One type of CFAE is continuous electrical activity (CEA). The prevalence and characteristics of CEA in patients with paroxysmal and persistent AF are unclear.
Methods and Results:
In 44 patients (age = 59 ± 8 years) with paroxysmal (25) or persistent (19) AF, bipolar electrograms were systematically recorded for ≥5 seconds at 24 left atrial (LA) sites, including 8 antral sites, and 2 sites within the coronary sinus (CS). CEA was defined as continuous depolarization for >1 second with no isoelectric interval. CEA was recorded at the LA septum (79%), antrum (66%), posterior (68%) and anterior walls (67%), roof (66%), base of the LA appendage (61%), inferior wall (61%), posterior mitral annulus (48%), CS (41%), and in the LA appendage (14%). Antral CEA was equally prevalent in patients with paroxysmal (63%) and persistent AF (70%, P = 0.12). In patients with paroxysmal AF, the prevalence of CEA was similar among antral and nonantral LA sites, except for the LA appendage. However, in patients with persistent AF, CEA was more prevalent at the nonantral (80%) than antral sites (70%, P = 0.03). CEA at nonantral sites except the CS was more prevalent in persistent than in paroxysmal AF (80% vs 57%, P < 0.001). The mean duration of intermittent episodes of CEA was longer in persistent than in paroxysmal AF (P < 0.001).
Conclusions:
The higher prevalence and duration of CEA at nonantral sites in persistent than in paroxysmal AF is consistent with a greater contribution of LA reentrant mechanisms in persistent AF. However, the high prevalence of CEA at nonantral sites in paroxysmal atrial fibrillation (PAF) suggests that CEA alone is a nonspecific marker of appropriate target sites for ablation of AF. The characteristics of CEA that most accurately identify drivers of AF remain to be determined.
Coronary Sinus Focus Acting as a Trigger for Atrial Fibrillation in a Patient with Orthotopic Heart Transplantation
Authors: KANJ MOHAMED , DI BIASE LUIGI , WAZNI OUSSAMA , NATALE ANDREA 
Published: March 2008

We report the case of a 46‐year‐old man who presented for evaluation and ablation of paroxysmal atrial fibrillation, which he developed one year prior to presentation and that was refractory to antiarrhythmic drugs. His past medical and surgical history was significant for orthotopic heart transplantation (OHTX) and idiopathic nonfamilial dilated cardiomyopathy.We present the first case of post OHTX where the coronary sinus was acting as a trigger and driver for atrial fibrillation. This illustrates an unusual role of nonpulmonary vein foci in the etiology of atrial fibrillation in patients status post OHTX.
Internationalizing the Broselow Tape: How Reliable Is Weight Estimation in Indian Children
Authors: Ramarajan Naresh , Krishnamoorthi Rajesh , Strehlow Matthew , Quinn James , Mahadevan Swaminatha V. 
Published: March 2008

AbstractObjectives:  The Broselow pediatric emergency weight estimation tape is an accurate method of estimating children’s weights based on height–weight correlations and determining standardized medication dosages and equipment sizes using color‐coded zones. The study objective was to determine the accuracy of the Broselow tape in the Indian pediatric population.Methods:  The authors conducted a 6‐week prospective cross‐sectional study of 548 children at a government pediatric hospital in Chennai, India, in three weight‐based groups: <10 kg (n = 175), 10–18 kg (n = 197), and >18 kg (n = 176). Measured weight was compared to Broselow‐predicted weight, and the percentage difference was calculated. Accuracy was defined as agreement on Broselow color‐coded zones, as well as agreement within 10% between the measured and Broselow‐predicted weights. A cross‐validated correction factor was also derived.Results:  The mean percentage differences were −2.4, −11.3, and −12.9% for each weight‐based group. The Broselow color‐coded zone agreement was 70.8% in children weighing less than 10 kg, but only 56.3% in the 10‐ to 18‐kg group and 37.5% in the >18‐kg group. Agreement within 10% was 52.6% for the <10‐kg group, but only 44.7% for the 10‐ to 18‐kg group and 33.5% for the >18‐kg group. Application of a 10% weight‐correction factor improved the percentages to 77.1% for the 10‐ to 18‐kg group and 63.0% for the >18‐kg group.Conclusions:  The Broselow tape overestimates weight by more than 10% in Indian children >10 kg. Weight overestimation increases the risk of medical errors due to incorrect dosing or equipment selection. Applying a 10% weight‐correction factor may be advisable.
A Decision Rule for Predicting Bacterial Meningitis in Children with Cerebrospinal Fluid Pleocytosis When Gram Stain Is Negative or Unavailable
Authors: Bonsu Bema K. , Ortega Henry W. , Marcon Mario J. , Harper Marvin B. 
Published: March 2008

AbstractObjectives:  Among children with cerebrospinal fluid (CSF) pleocytosis, the task of separating aseptic from bacterial meningitis is hampered when the CSF Gram stain result is unavailable, delayed, or negative. In this study, the authors derive and validate a clinical decision rule for use in this setting.Methods:  This was a review of peripheral blood and CSF test results from 78 children (<19 years) presenting to Children’s Hospital Columbus from 1998 to 2002. For those with a CSF leukocyte count of >7/μL, a rule was created for separating bacterial from viral meningitis that was based on routine laboratory tests, but excluded Gram stain. The rule was validated in 158 subjects seen at the same site (Columbus, 2002–2004) and in 871 subjects selected from a separate site (Boston, 1993–1999).Results:  One point each (maximum, 6 points) was assigned for leukocytes >597/μL, neutrophils >74%, glucose <38 mg/dL, and protein >97 mg/dL in CSF and for leukocytes >17,000/mL and bands to neutrophils >11% in peripheral blood. Areas under receiver‐operator‐characteristic curves (AROCs) for the resultant score were 0.98 for the derivation set and 0.90 and 0.97, respectively, for validation sets from Columbus and Boston. Sensitivity and specificity pairs for the Boston data set were 100 and 44%, respectively, at a score of 0 and 97 and 81% at a score of 1. Likelihood ratios (LRs) increased from 0 at a score of 0 to 40 at a score of ≥4.Conclusions:  Among children with CSF pleocytosis, a prediction score based on common tests of CSF and peripheral blood and intended for children with unavailable, negative, or delayed CSF Gram stain results has value for diagnosing bacterial meningitis.
Gender Disparity in Analgesic Treatment of Emergency Department Patients with Acute Abdominal Pain
Authors: Chen Esther H. , Shofer Frances S. , Dean Anthony J. , Hollander Judd E. , Baxt William G. , Robey Jennifer L. , Sease Keara L. , Mills Angela M. 
Published: March 2008

AbstractObjectives:  Oligoanalgesia for acute abdominal pain historically has been attributed to the provider’s fear of masking serious underlying pathology. The authors assessed whether a gender disparity exists in the administration of analgesia for acute abdominal pain.Methods:  This was a prospective cohort study of consecutive nonpregnant adults with acute nontraumatic abdominal pain of less than 72 hours’ duration who presented to an urban emergency department (ED) from April 5, 2004, to January 4, 2005. The main outcome measures were analgesia administration and time to analgesic treatment. Standard comparative statistics were used.Results:  Of the 981 patients enrolled (mean age ± standard deviation [SD] 41 ± 17 years; 65% female), 62% received any analgesic treatment. Men and women had similar mean pain scores, but women were less likely to receive any analgesia (60% vs. 67%, difference 7%, 95% confidence interval [CI] = 1.1% to 13.6%) and less likely to receive opiates (45% vs. 56%, difference 11%, 95% CI = 4.1% to 17.1%). These differences persisted when gender‐specific diagnoses were excluded (47% vs. 56%, difference 9%, 95% CI = 2.5% to 16.2%). After controlling for age, race, triage class, and pain score, women were still 13% to 25% less likely than men to receive opioid analgesia. There was no gender difference in the receipt of nonopioid analgesia. Women waited longer to receive their analgesia (median time 65 minutes vs. 49 minutes, difference 16 minutes, 95% CI = 3.5 to 33 minutes).Conclusions:  Gender bias is a possible explanation for oligoanalgesia in women who present to the ED with acute abdominal pain. Standardized protocols for analgesic administration may ameliorate this discrepancy.
Compliance with Recommended Cancer Screening among Emergency Department Patients: A Multicenter Survey
Authors: Ginde Adit A. , Millen Jennifer C. , Love Jennifer S. , Pang Jessica M. , Camargo Carlos A 
Published: March 2008

AbstractObjectives:  The objectives were to measure compliance with, and possible sociodemographic disparities for, cancer screening among emergency department (ED) patients.Methods:  This was a cross‐sectional survey in three academic EDs in Boston. The authors enrolled consecutive adult patients during two 24‐hour periods at each site. Self‐reported compliance with standard recommendations for cervical, breast, testicular, and prostate cancer screening were measured. The chi‐square test was used test to evaluate associations between demographic variables and cancer screening compliance.Results:  The authors enrolled 387 patients (81% of those eligible). The participants had a mean (±standard deviation) age of 44 (±18) years and were 52% female, 16% Hispanic, and 65% white. Sixty‐seven percent (95% confidence interval [CI] = 60% to 73%) of all women reported Pap smear examinations in the past 3 years, 92% (95% CI = 85% to 96%) of women aged ≥40 years reported clinical breast examinations, and 88% (95% CI = 81% to 94%) of women aged ≥40 years reported mammography. Fifty‐one percent (95% CI = 40% to 61%) of men aged 18–39 years reported testicular self‐examinations, and among men aged ≥40 years, 79% (95% CI = 69% to 87%) reported digital rectal examinations (DREs) and 51% (95% CI = 40% to 61%) reported prostate‐specific antigen (PSA) testing. Racial and ethnic minorities reported slightly lower rates of clinical breast examinations and testicular self‐examinations.Conclusions:  Most women and a majority of men in our ED‐based study were compliant with recommended measures of cervical, breast, testicular, and prostate cancer screening. No large sociodemographic disparities in our patient population were identified. Based on these data, and the many other pressing public health needs of our ED population, the authors would be reluctant to promote ED‐based cancer screening initiatives at this time.