bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of density estimation methods for mammal populations with camera traps in the Kaa‐Iya del Gran Chaco landscape
Authors: Noss A. J. , Gardner B. , Maffei L. , Cuéllar E. , Montaño R. , Romero‐Muñoz A. , Sollman R. , O'Connell A. F. 
Published: April 2012

AbstractSampling animal populations with camera traps has become increasingly popular over the past two decades, particularly for species that are cryptic, elusive, exist at low densities or range over large areas. The results have been widely used to estimate population size and density. We analyzed data from 13 camera trap surveys conducted at five sites across the Kaa‐Iya landscape, Bolivian Chaco, for jaguar, puma, ocelot and lowland tapir. We compared two spatially explicit capture–recapture (SCR) software packages: secr, a likelihood‐based approach, and SPACECAP, a Bayesian approach, both of which are implemented within the R environment and can be used to estimate animal density from photographic records of individual animals that simultaneously employ spatial information about the capture location relative to the sample location. As a non‐spatial analysis, we used the program CAPTURE 2 to estimate abundance from the capture–recapture records of individuals identified through camera trap photos combined with an ad hoc estimation of the effective survey area to estimate density. SCR methods estimated jaguar population densities from 0.31 to 1.82 individuals per 100 km2 across the Kaa‐Iya sites; puma from 0.36 to 7.99; ocelot from 1.67 to 51.7; and tapir from 7.38 to 42.9. Density estimates using either secr or SPACECAP were generally lower than the estimates generated using the non‐spatial method for all surveys and species; and density estimates using SPACECAP were generally lower than that using secr. We recommend using either secr or SPACECAP because the spatially explicit methods are not biased by an informal estimation of an effective survey area. Although SPACECAP and secr are less sensitive than non‐spatial methods to the size of the grid used for sampling, we recommend grid sizes several times larger than the average home range (known or estimated) of the target species.
Echogenicity of the carotid intima–media complex and cardiovascular risk factors
Authors: De Blois Jonathan , Stranden Einar , Jogestrand Tomas , Henareh Loghman , Agewall Stefan 
Published: April 2012

SummaryIntroductionIncreased carotid intima–media thickness (IMT) has been associated with increased risk of myocardial infarction (MI) and stroke. A measure of echogenicity, the grey scale median (GSM), has been shown to be inversely correlated with cardiovascular risk factors and to be predictive of mortality in a community‐based cohort. We assessed the factors associated with carotid IM–GSM in younger, non‐diabetic patients with a recent MI.Methods and resultsA total of 122 patients (women, 25%) aged 31–80 years (61) were recruited 2–3 days after an acute MI. Ultrasound examinations of the carotid arteries were performed 1–12 months after the MI. IMT was 0·78 (SD 0·17) mm on the right side and 0·81 (0·20) mm on the left side (P = 0·05). GSM was 88·60 (range 46–132, SD 18·32) on the right side and 82·10 (40–126, 17·89) on the left side (P = 0·002). Triglycerides (TG) correlated with GSM on both sides (right, r = −0·27, P = 0·003; left, r = −0·18, P = 0·05). On the right side, GSM was 92·15 and 82·26 (P = 0·05) in patients with TG < and ≥1·7, and on the left side, it was 84·04 and 74·55 (P = 0·02) in patients with TG < and ≥2·3. On multivariate analysis, TG were significantly associated with GSM, both on the right side (P = 0·01) and on the left side (P = 0·009).ConclusionWe found a negative association between TG and carotid IM–GSM on both sides in patients with a recent MI. Our results also suggest that atherosclerosis progression may be faster on the left side in patients with coronary heart disease.
Optical quality for keratoconic eyes with conventional RGP lens and simulated, customised contact lens corrections: a comparison
Authors: Jinabhai Amit , Neil Charman W , O’Donnell Clare , Radhakrishnan Hema 
Published: April 2012

Citation information: Jinabhai A, Charman WN, O’Donnell C & Radhakrishnan H. Optical quality for keratoconic eyes with conventional RGP lens and simulated, customised contact lens corrections: a comparison. Ophthalmic Physiol Opt 2012, 32, 200–212. doi: 10.1111/j.1475‐1313.2012.00904.xAbstractPurpose:  To compare monochromatic aberrations of keratoconic eyes when uncorrected, corrected with spherically‐powered RGP (rigid gas‐permeable) contact lenses and corrected using simulations of customised soft contact lenses for different magnitudes of rotation (up to 15°) and translation (up to 1 mm) from their ideal position.Methods:  The ocular aberrations of examples of mild, moderate and severe keratoconic eyes were measured when uncorrected and when wearing their habitual RGP lenses. Residual aberrations and point‐spread functions of each eye were simulated using an ideal, customised soft contact lens (designed to neutralise higher‐order aberrations, HOA) were calculated as a function of the angle of rotation of the lens from its ideal orientation, and its horizontal and vertical translation.Results:  In agreement with the results of other authors, the RGP lenses markedly reduced both lower‐order aberrations and HOA for all three patients. When compared with the RGP lens corrections, the customised lens simulations only provided optical improvements if their movements were constrained within limits which appear to be difficult to achieve with current technologies.Conclusions:  At the present time, customised contact lens corrections appear likely to offer, at best, only minor optical improvements over RGP lenses for patients with keratoconus. If made in soft materials, however, these lenses may be preferred by patients in term of comfort.
Employee Selection as a Control System
Authors: CAMPBELL DENNIS 
Published: April 2012

ABSTRACTTheories from the economics, management control, and organizational behavior literatures predict that when it is difficult to align incentives by contracting on output, aligning preferences via employee selection may provide a useful alternative. This study investigates this idea empirically using personnel and lending data from a financial services organization that implemented a highly decentralized business model. I exploit variation in this organization in whether or not employees are selected via channels that are likely to sort on the alignment of their preferences with organizational objectives. I find that employees selected through such channels are more likely to use decision‐making authority in the granting and structuring of consumer loans than those who are not. Conditional on using decision‐making authority, their decisions are also less risky ex post. These findings demonstrate employee selection as an important, but understudied, element of organizational control systems.
Adult Polycystic Kidney Disease: Who Needs Hospital Follow‐Up?
Authors: Griveas Ioannis , Bishop Kathryn , World Michael 
Published: April 2012

AbstractClinical data from 120 adult patients with genetically undifferentiated polycystic kidney disease who had been followed up for more than 3 months (range 3–172) were reviewed in order to try to identify clinical indicators that might predict deterioration in renal function. They were split into two groups dependent on whether annualized fall in estimated glomerular filtration rate (ΔeGFR mL/min/1.73 m2/year) was statistically significant or not. Only 26 patients (22%) had a statistically significantly decreasing ΔeGFR with a median decrease of −2.6 mL/min/1.73 m2/year (range −6.2 to −0.7). There was no difference in initial age, gender, or racial distributions between the groups or in initial eGFR. Follow‐up was longer (median 86, range 23–172 months vs. 46, range 3–161 months; P =  0.002) and initial blood pressure values tended to be lower (with mean systolic values of 128 vs. 148 mm Hg; P = 0.02) in the group with statistically significant fall in ΔeGFR, but this trend failed to achieve an a priori level of statistical significance. However, the proportion of patients with initial systolic blood pressure ≤144 developing a statistically significant fall in ΔeGFR was 0.26 (95% confidence interval = 0.13 to 0.45). No differences were found in initial hemoglobin or cholesterol concentrations. Overall, the annualized rate of decrease in eGFR tended to be greater in those with the higher initial eGFR (P = 0.04), but correlation was poor (rho2= 0.04) and failed to achieve an a priori level of statistical significance. No statistically significant correlation was found between ΔeGFR and any other variable. Only those patients with polycystic kidney disease with a statistically significant annualized decrease in eGFR may need to be referred for hospital follow‐up in the renal clinic. This simple selection would reduce referrals by 78%.
Physiological Performance of a Detergent Decellularized Heart Valve Implanted for 15 Months in Vietnamese Pigs: Surgical Procedure, Follow‐up, and Explant Inspection
Authors: Gallo Michele , Naso Filippo , Poser Helen , Rossi Antonio , Franci Paolo , Bianco Roberto , Micciolo Matteo , Zanella Fabio , Cucchini Umberto , Aresu Luca , Buratto Edward , Busetto Roberto , Spina Michele , Gandaglia Alessandro , Gerosa Gino 
Published: April 2012

AbstractThis study features the longest experimental follow‐up for decellularized heart valves implanted in an animal model. Porcine aortic heart valves were decellularized according to a disclosed standardized method in which TRITON X‐100 and sodium cholate (TRICOL) are used in succession, followed by a further treatment with the endonuclease Benzonase to completely remove the nucleic acid remnants. Experimental animals (n = 17), represented by Vietnamese pigs (VPs), received a decellularized aortic allograft as a substitute for the replacement of their right ventricular outflow tract. The surgical implantation of the TRICOL‐treated aortic valve conduit was successful in 11 VPs, while perioperative or postoperative complications occurred in the remaining six animals. In the sham‐operated group (n = 4), the native pulmonary root was excised and immediately reimplanted orthotopically in the same animal. Echocardiography demonstrated a satisfactory hemodynamic performance of the TRICOL‐treated valves during follow‐up as well as the absence of relevant leaflet alterations concerning thickness and motility or valve insufficiency. At explantation, macroscopic inspection of tissue‐engineered heart valve conduits did not evidence calcifications and showed a decreased wall thickness, comparable to that of the reimplanted native pulmonary roots. Noteworthy, extended functional performance, recovery of DNA content, and active extracellular matrix precursor incorporation are apparently compatible with the properties of a living self‐supporting substitute.
Prosthodontic Rehabilitation for Total Glossectomy with a Magnetic Detachable Mandibular Tongue Prosthesis: A Clinical Report
Authors: Sabouri Amir A. , Safari Anahita , Gharechahi Jafar , Esmailzadeh Samira 
Published: April 2012

AbstractTotal glossectomy can result in significant functional impairments in mastication, swallowing, and speech. In addition to these functional problems, severe psychological problems may follow complete loss of the tongue. Placement of a mandibular tongue prosthesis obturates this large defect, increases the patient's ability to produce intelligible sounds, and assists with a return to a normal diet. Prosthetic rehabilitation can also improve the user's appearance and psychosocial adjustment. This clinical report describes a magnetically attached two‐piece tongue prosthesis used to treat a patient who underwent total glossectomy.
An Econometric Model of the Term Structure of Interest‐Rate Swap Yields
Authors: DUFFIE DARRELL , SINGLETON KENNETH J. 
Published: April 2012

ABSTRACTThis article develops a multi‐factor econometric model of the term structure of interest‐rate swap yields. The model accommodates the possibility of counterparty default, and any differences in the liquidities of the Treasury and Swap markets. By parameterizing a model of swap rates directly, we are able to compute model‐based estimates of the defaultable zero‐coupon bond rates implicit in the swap market without having to specify a priori the dependence of these rates on default hazard or recovery rates. The time series analysis of spreads between zero‐coupon swap and treasury yields reveals that both credit and liquidity factors were important sources of variation in swap spreads over the past decade.
The Cyclical Behavior of Interest Rates
Authors: ROMA ANTONIO , TOROUS WALTER 
Published: April 2012

ABSTRACTThis article investigates the behavior of the term structure of interest rates over the business cycle. In contrast to prior studies that measure the business cycle by the simple growth in aggregate economic activity, we consider the deviation of aggregate economic activity from its potentially stochastic trend. We show that incorporating both an independent trend and cyclical component in consumption improves the efficiency in estimating consumption‐based asset pricing models. We also find that the term spread is more informative about future changes in stochastically detrended real gross domestic product (GDP) than future growth rates in real GDP.
The Market for Equity Options in the 1870s
Authors: KAIRYS JOSEPH P. , VALERIO NICHOLAS 
Published: April 2012

ABSTRACTThe introduction of exchange‐traded options in 1973 led to explosive growth in the stock options market, but put and call options on equity securities have existed for more than a century. Prior to the listing of option contracts, trading was conducted in an order‐driven over‐the‐counter market. From 1873 to 1875, quotes for options contracts were published weekly in The Commercial and Financial Chronicle during a period that saw extensive marketing efforts by a number of brokerage firms. In this article we examine these quotes to determine why this seemingly sophisticated market existed for only a brief period in financial history.
Market Segmentation and Stock Prices: Evidence from an Emerging Market
Authors: DOMOWITZ IAN , GLEN JACK , MADHAVAN ANANTH 
Published: April 2012

ABSTRACTWe examine the relationship between stock prices and market segmentation induced by ownership restrictions in Mexico. The focus is on multiple classes of equity that differentiate between foreign and domestic traders, and between domestic individuals and institutions. Significant stock price premia are documented for shares not restricted to a particular investor group. We analyze the theoretical and empirical determinants of premia across firms and over time. In addition to economy‐wide factors, segmentation reflects the relative scarcity of unrestricted shares. The results provide additional support for Stulz and Wasserfallen's (1995) hypothesis that firms discriminate between investor groups with different demand elasticities.
Symposium on Public Policy Issues in Finance
Authors: LELAND HAYNE E. , FELDSTEIN MARTIN , GLAUBER ROBERT R. , MULLINS DAVID W. , WALLMAN STEVEN M. H. 
Published: April 2012

ABSTRACTThe thesis of this symposium, organized by James Bicksler, was that while finance theory will surely inform practitioners, it seems appropriate to pay some attention to the opposite flow: practitioners can inform theory. Contributors include a distinguished group of practitioners with extensive backgrounds in economics, and economists with extensive public policy experience: Martin Feldstein, Robert Glauber, David Mullins, and Steven Wallman. Their topics range from privatizing social security, to managing market crashes, to the regulatory agency cost problem, to regulatory constraints in a technologically advanced world.
Myth or Reality? The Long‐Run Underperformance of Initial Public Offerings: Evidence from Venture and Nonventure Capital‐Backed Companies
Authors: BRAV ALON , GOMPERS PAUL A. 
Published: April 2012

ABSTRACTWe investigate the long‐run underperformance of recent initial public offering (IPO) firms in a sample of 934 venture‐backed IPOs from 1972–1992 and 3,407 nonventure‐backed IPOs from 1975–1992. We find that venture‐backed IPOs outperform non‐venture‐backed IPOs using equal weighted returns. Value weighting significantly reduces performance differences and substantially reduces underperformance for nonventure‐backed IPOs. In tests using several comparable benchmarks and the Fama‐French (1993) three factor asset pricing model, venture‐backed companies do not significantly underperform, while the smallest nonventure‐backed firms do. Underperformance, however, is not an IPO effect. Similar size and book‐to‐market firms that have not issued equity perform as poorly as IPOs.
Trading Costs and Exchange Delisting: The Case of Firms that Voluntarily Move from the American Stock Exchange to the Nasdaq
Authors: CLYDE PAUL , SCHULTZ PAUL , ZAMAN MIR 
Published: April 2012

ABSTRACTWe examine 47 stocks that voluntarily left the American Stock Exchange from 1992 through 1995 and listed on the Nasdaq. We find that both effective and quoted spreads increase by about 100 percent after listing on the Nasdaq. These spread changes are consistent across stocks. In contrast, excess returns are positive when firms announce a switch from The American Stock Exchange to the Nasdaq. We are unable to explain this apparent contradiction.
Transactions Costs and Capital Structure Choice: Evidence from Financially Distressed Firms
Authors: GILSON STUART C. 
Published: April 2012

ABSTRACTThis study provides evidence that transactions costs discourage debt reductions by financially distressed firms when they restructure their debt out of court. As a result, these firms remain highly leveraged and one‐in‐three subsequently experience financial distress. Transactions costs are significantly smaller, hence leverage falls by more and there is less recurrence of financial distress, when firms recontract in Chapter 11. Chapter 11 therefore gives financially distressed firms more flexibility to choose optimal capital structures.
Equity Issuance and Adverse Selection: A Direct Test Using Conditional Stock Offers
Authors: HOUSTON JOEL F. , RYNGAERT MICHAEL D. 
Published: April 2012

ABSTRACTWe conduct a unique test of adverse selection in the equity issuance process. While common stock is the dominant means of payment in bank mergers, stock acquisition agreements provide target shareholders with varying degrees of protection against adverse price movements in the bidder's stock between the time of the merger agreement and the time of merger completion. We show that it is the degree of protection against adverse price changes and not the percent of stock offered in a bank merger that explains bidder merger announcement abnormal returns. This result is difficult to explain outside of an adverse selection framework.
Competition and Collusion in Dealer Markets
Authors: DUTTA PRAJIT K. , MADHAVAN ANANTH 
Published: April 2012

ABSTRACTThis article develops a game‐theoretic model to analyze market makers' intertemporal pricing strategies. We show that dealers who adopt noncooperative pricing strategies may set bid‐ask spreads above competitive levels. This form of “implicit collusion” differs from explicit collusion, where dealers cooperate to fix prices. Price discreteness or asymmetric information are not required for collusion to occur. Rather, institutional arrangements that restrict access to the order flow are important determinants of the ability to collude because they reduce dealers' incentives to compete on price. Public policy efforts to increase interdealer competition should focus on such restrictions.
Third Market Broker‐Dealers: Cost Competitors or Cream Skimmers?
Authors: BATTALIO ROBERT H. 
Published: April 2012

ABSTRACTThis article compares the bid‐ask spread for New York Stock Exchange (NYSE)‐listed securities before and after a major third market broker‐dealer, Bernard L. Madoff Investment Securities (Madoff), begins to selectively purchase and execute orders in those securities. Tests reveal the quoted bid‐ask spread tightens when Madoff enters the market. Furthermore, trading costs as measured by the difference between the transaction price and the midpoint of the contemporaneous bid‐ask spread do not increase. Together, these results suggest that the adverse selection problem associated with allowing agents to selectively execute orders in exchange‐listed securities may be economically insignificant.
The Pricing of Initial Public Offers of Corporate Straight Debt
Authors: DATTA SUDIP , ISKANDAR-DATTA MAI , PATEL AJAY 
Published: April 2012

ABSTRACTThis study examines the initial‐day and aftermarket price performance of corporate straight debt IPOs. We find that IPOs of speculative grade debt are underpriced like equity IPOs, while those rated investment grade are overpriced. IPOs of investment grade debt are typically issued by firms listed on the major exchanges and underwritten by prestigious underwriters. In contrast, junk bond IPOs are more likely to be handled by less prestigious underwriters and are typically issued by OTC firms. Our analysis also reveals that bond rating, market listing of the firm, and investment banker quality are significant determinants of bond IPO returns.
Closed Form Solutions for Term Structure Derivatives with Log‐Normal Interest Rates
Authors: MILTERSEN KRISTIAN R. , SANDMANN KLAUS , SONDERMANN DIETER 
Published: April 2012

ABSTRACTWe derive a unified model that gives closed form solutions for caps and floors written on interest rates as well as puts and calls written on zero‐coupon bonds. The crucial assumption is that simple interest rates over a fixed finite period that matches the contract, which we want to price, are log‐normally distributed. Moreover, this assumption is shown to be consistent with the Heath‐Jarrow‐Morton model for a specific choice of volatility.
How Much Do Taxes Discourage Incorporation?
Authors: MACKIE‐MASON JEFFREY K. , GORDON ROGER H. 
Published: April 2012

ABSTRACTThe double taxation of corporate income should discourage firms from incorporating. We investigate the extent to which the aggregate allocation of assets and taxable income in the United States between corporate and noncorporate firms responds to the size of this tax distortion during the period 1959–1986. In theory, profitable firms should shift out of the corporate sector when the tax distortion is large, and conversely for firms with tax losses. Our empirical results provide strong support for these forecasts, and imply that the resulting excess burden equals 16 percent of business tax revenue.
Assessing Goodness‐of‐Fit of Asset Pricing Models: The Distribution of the Maximal R2
Authors: FOSTER F. DOUGLAS , SMITH TOM , WHALEY ROBERT E. 
Published: April 2012

ABSTRACTThe development of asset pricing models that rely on instrumental variables together with the increased availability of easily‐accessible economic time‐series have renewed interest in predicting security returns. Evaluating the significance of these new research findings, however, is no easy task. Because these asset pricing theory tests are not independent, classical methods of assessing goodness‐of‐fit are inappropriate. This study investigates the distribution of the maximal when k of m regressors are used to predict security returns. We provide a simple procedure that adjusts critical values to account for selecting variables by searching among potential regressors.