Separate Estimates Research Articles

Maximum simulated likelihood estimation of the seemingly unrelated stochastic frontier regressions

In this paper, we use the maximum simulated likelihood (MSL) approach to estimate multiple stochastic frontier (SF) models with random effects and correlated composite errors. We show that the separate estimation of the single equation ignores the correlation between the composite errors and causes significant efficiency loss in estimation. In addition to using Monte Carlo simulation to investigate the finite sample performance of the simulated estimator, we demonstrate the usefulness of our approach in estimating the technical efficiency of Taiwan’s international hotels based on their accommodation and restaurant divisions.

The First Boundary Problem for a Mixed Type Equation with Characteristic Degeneracy with Discontinuous Frankl Condition

For an equation of mixed elliptic-hyperbolic type of the second kind, the boundary problem in a rectangular region is studied. The criterion of uniqueness is established. The solution is built as a sum row. When substantiating convergence, the problem of small denominators. In this connection, estimates of separation from zero small denominators with the corresponding asymptotics, which and allowed us to justify the existence of a solution in the class of regular solutions and solution stability from boundary data.

Block sparse representation approach to 2D DOA and polarisation estimation of wideband signals using a sparse vector antenna array

In this study, a multi-polarised two-dimensional (2D) planar array of sparsely located vector antennas (VAs) is designed for the block sparse representation (SR)-based 2D direction finding and polarisation parameter estimation of wideband signals. In order to alleviate the inter-VA mutual coupling effect, the minimum inter-VA spacing of the 2D sparse array is constrained to be no less than one wavelength that corresponds to the highest signal frequency. To reduce the computational complexity of parameter estimation, the 2D block SR model for the 2D difference coarray output at a certain frequency bin is established, under which the two direction cosine terms for 2D direction-of-arrival (DOA) estimation are decoupled with the polarimetric terms. This enables separated but simultaneous 2D direction finding and polarisation parameter estimation with the newly developed joint 2D block orthogonal matching pursuit (Joint-2D-BOMP) subband fused sparse recovery algorithm. Moreover, with the use of two spatial only (polarisation independent) over-complete dictionaries, the representation dimension of the new 2D block SR model is greatly reduced as compared with the traditional space-polarisation joint SR model. The efficacy of the presented VA array geometry and the associated parameter estimation method is validated by computer simulations.

Two-Step Phase-Shifting Algorithm Based on the Quadratic Spatial Filtering of Interferograms

By using the quadratic spatial filtering (QSF) operation of interferograms, we propose a fast and accurate phase retrieval algorithm in 2-step phase-shifting interferometry (PSI), in which both the interference signal separation and blind phase shift estimation can be realized. Compared with the existed 2-step PSI algorithms, the proposed QSF algorithm reveals two advantages: First, when the background intensity is not accurately estimated, which is a serious problem in 2-step PSI, the distortion of the retrieved phase can be released. Second, there is no requirement about the fringe density of interference pattern, reflecting the phase shift estimation can be realized even if the fringes density is sparse. The former is a valuable solution to reduce most significant errors in 2-step PSI, and the latter makes the accuracy robust against different fringe patterns. Both the simulation and experimental results demonstrate the excellent performance of the proposed QSF algorithm.

Improvements in cosmological constraints from breaking growth degeneracy

Context. The key probes of the growth of a large-scale structure are its rate f and amplitude σ8. Redshift space distortions in the galaxy power spectrum allow us to measure only the combination fσ8, which can be used to constrain the standard cosmological model or alternatives. By using measurements of the galaxy-galaxy lensing cross-correlation spectrum or of the galaxy bispectrum, it is possible to break the fσ8 degeneracy and obtain separate estimates of f and σ8 from the same galaxy sample. Currently there are very few such separate measurements, but even this allows for improved constraints on cosmological models. Aims. We explore how having a larger and more precise sample of such measurements in the future could constrain further cosmological models. Methods. We considered what can be achieved by a future nominal sample that delivers an ∼1% constraint on f and σ8 separately, compared to the case with a similar precision on the combination fσ8. Results. For the six cosmological parameters of ΛCDM, we find improvements of ∼5–50% on their constraints. For modified gravity models in the Horndeski class, the improvements on these standard parameters are ∼0–15%. However, the precision on the sum of neutrino masses improves by 65% and there is a significant increase in the precision on the background and perturbation Horndeski parameters.

The determinants of life satisfaction among Chilean workers

This article puts forward evidence to identify the different domains that contribute to life satisfaction among a sample of Chilean workers, using the two-layer model developed by van Praag, Frijters and Ferrer-i-Carbonell (2003). The results show that satisfaction in the domains of money, privacy, leisure, family life, health and work have a positive (and statistically significant) effect on life satisfaction, when controlling for a variable that attempts to measure workers’ personality traits. The evidence reveals that the effects of family life, leisure, health and work outweigh those of money and privacy. Separate estimations were made by gender, age and educational level, to analyse heterogeneity in the relationship between degrees of satisfaction in the different life domains and overall life satisfaction. The results are robust to the different specifications used to explain satisfaction domains.

Three-dimension extracting transform

In this paper, we consider a three-dimensional parameter space, which is the time-frequency-chirprate (TFCR), to characterize the time-varying features of multi-component non-stationary signals. A highly concentrated TFCR representation, named as the three-dimension extracting transform (TET), is proposed based on instantaneous frequency (IF) and chirprate (CR) equations. The CRs and IFs can be jointly estimated via the TET, and the spectral clustering algorithm is applied for component separation. To avoid the influence of the CR parameter on the IF identification, a nonlinear exponential transform of the IF and CR equations is introduced. We further give a TET reconstruction with the theoretical analysis. By employing the TET, the signals crossing in the time-frequency domain can be well separated and robust IF estimation can be obtained. Numerical experiments on simulated signals demonstrate the effectiveness of the proposed approach.

Modified Commercial Fish Trap to Help Eliminate Salmonid Bycatch Mortality

AbstractThe utility of commercial salmonid Oncorhynchus spp. traps in the U.S. Pacific Northwest was recently revisited for the first time in decades to enable selective harvesting of hatchery‐origin salmonids while reducing mortality of Endangered Species Act (ESA)‐listed salmonids. Modifications to historical gear designs resulted in dramatic improvements in salmonid bycatch survival rates relative to conventional commercial gears in the lower Columbia River. Expanding upon this work, an experimental commercial fish trap was further modified to largely eliminate net contact, air exposure, handling, and crowding of fish. Studies were conducted from May to November 2019 in the lower Columbia River to estimate survival of bycatch and evaluate potential benefits from the modified passive capture design. Analyzed through two separate survival estimation techniques, the modified trap demonstrated no detectable effect on salmon release survival and a significant improvement over the previous prototype design. Estimated through a paired release–recapture methodology, the relative survival effect of catch and release compared to controls over a 400‐km migration was 1.017 ( = 0.032) for adult Sockeye Salmon O. nerka. For adult Coho Salmon O. kisutch that were held captive for a 48‐h postrelease period, estimated survival (S) was 1.000 (lower 95% confidence limit: S ≥ 0.978). These results suggest that trap modifications can be made to significantly reduce bycatch mortality of ESA‐listed salmonids and provide increased opportunity for harvest of hatchery‐origin salmonids.

Comparing Eight Parameter Estimation Methods for the Ratcliff Diffusion Model Using Free Software.

The Ratcliff Diffusion Model has become an important and widely used tool for the evaluation of psychological experiments. Concurrently, numerous programs and routines have appeared to estimate the model's parameters. The present study aims at comparing some of the most widely used tools with special focus on freely available routines (i.e., open source). Our simulations show that (1) starting point and non-decision time were recovered better than drift rate, (2) the Bayesian approach outperformed all other approaches when the number of trials was low, (3) the Kolmogorov-Smirnov and χ2 approaches revealed more bias than Bayesian or Maximum Likelihood based routines, and (4) EZ produced substantially biased estimates of threshold separation, non-decision time and drift rate when starting point z ≠ a/2. We discuss the implications for the choice of parameter estimation approaches for real data and suggest that if biased starting point cannot be excluded, EZ will produce deviant estimates and should be used with great care.

Association of Federal Regulations in the United States and Canada With Potential Corneal Donation by Men Who Have Sex With Men

Federal policy in the United States prohibits corneal donation by men who have had sex with another man (MSM) in the preceding 5 years, whereas Canada enforces a 12-month ban. The potential consequences of these policies on corneal donations should be evaluated. To estimate the number of potential corneal donations associated with MSM deferral policies in the United States and Canada. A nonvalidated telephone survey study was conducted of all 65 eye banks in the United States and Canada to investigate how many potential corneal donors were disqualified in 2018 because of federal MSM restrictions. Published demographic data were also used to arrive at a separate estimate. Survey data were gathered from May 2019 to February 2020. Eye banks were asked if they keep records of referrals disqualified specifically because of the federal MSM restrictions and, if so, how many referrals they disqualified in 2018 owing to MSM status. Fifty-four of 65 eye banks (83%) responded to the survey, with 30 eye banks reporting they do not keep specific records of MSM deferrals. The remaining 24 eye banks reported disqualifying 360 referrals in 2018 because of MSM status, equating to 720 corneas. The 24 eye banks accounted for 46.2% of corneal donations in the United States and Canada in 2018, yielding an estimate of approximately 1558 corneas rejected that year because of MSM status. A separate estimate using published MSM demographic data indicates that up to 3217 potential corneal donations may have been disqualified in 2018 because of these federal policies. Findings suggest that between 1558 and 3217 corneal donations were disqualified in 2018 because of federal regulations prohibiting corneal donation by men who have had sex with another man in the preceding 5 years in the United States or 1 year in Canada. With modern virologic testing that is reliable within days of HIV exposure and given the global shortage of corneal tissue, these policies should be reevaluated using current scientific evidence to increase the availability of vision-restoring surgery worldwide.

Dose to Lungs and Kidneys during Total Body Irradiation: Are We Delivering the Expected Dose?

Total Body irradiation (TBI)-based conditioning is key component for hemopoietic stem cell transplantation. TBI dose calculation is traditionally based on point-dose calculations based on estimates of body separation at different levels with the umbilicus as a reference point, an approach followed as standard protocol at most institutions. This homogenous dose calculation technique does not take into account tissue heterogeneity. Limited data exists for TPS-based TBI planning systems especially in the setting of lung and kidney partial transmission blocks, which is a void in our understanding of TBI dose delivery and is explored in this study. Primary objective of the study was to assess differences between radiation treatment planning software (TPS) estimated doses with heterogeneity correction and point calculation estimated doses when delivering TBI. Secondary objective was to validate accurate treatment delivery through optically stimulated luminescent dosimetry (OSLD) measurements at umbilicus obtained at first TBI fraction. Our retrospective study involved virtual dosimetric simulation of total body CT scan datasets in patients treated with a prescribed dose of 12 Gy in six fractions delivered twice daily over three days. Patients received TBI using a translating couch AP/PA technique with lung and kidney shielding (transmission blocks to achieve < 7 Gy point dose). The Varian Eclipse TPS was used to calculate the 3D dose distribution to the lungs, kidneys, and heart. Paired t-test with a significance value of 0.05 was used to compare means. 24 patients (Male-11, female-13; Age range: 23-60 years; Diagnosis: AML-7, ALL-8, HL-1, NHL-6, MDS-2) with total body CT scan datasets available were included in the analysis. Contrary to expected dose with shielding (< 7 Gy), the TPS simulated mean dose to lungs was 11.08 Gy (SD: 0.61, p= 9.66E-22) and to kidneys was 8.98 Gy (SD: 0.62, p: 2.31E-14). TPS mean dose to the unshielded heart was 11.38 Gy. Compared to the point dose calculation of 2 Gy at the midpoint of the umbilicus, the mean OSLD dose measured during the first fraction of treatment was 2.08 Gy (SD: 0.058, p: 2.07E-9). Using TPS of total body CT scan data, we demonstrated much higher than expected dose to lungs and kidneys than expected from point-based calculations. This study has triggered a comprehensive outcomes analysis of institutional data for assessing toxicities in patients receiving TBI 12 Gy-based conditioning prior to SCT with the goal to revisit the 7-Gy dose limit to the lungs and kidneys. Institutions are encouraged to pursue similar analyses of their TBI systems to refine dose to critical organs. (Supported by the Radiation Oncology Summer Research Fellowship and the Office of Student Research at the University of Maryland School of Medicine).

Planck2018 results

We analyse thePlanckfull-mission cosmic microwave background (CMB) temperature andE-mode polarization maps to obtain constraints on primordial non-Gaussianity (NG). We compare estimates obtained from separable template-fitting, binned, and optimal modal bispectrum estimators, finding consistent values for the local, equilateral, and orthogonal bispectrum amplitudes. Our combined temperature and polarization analysis produces the following final results:fNLlocal= −0.9 ± 5.1;fNLequil= −26 ± 47; andfNLortho= −38 ± 24 (68% CL, statistical). These results include low-multipole (4 ≤ ℓ &lt; 40) polarization data that are not included in our previous analysis. The results also pass an extensive battery of tests (with additional tests regarding foreground residuals compared to 2015), and they are stable with respect to our 2015 measurements (with small fluctuations, at the level of a fraction of a standard deviation, which is consistent with changes in data processing). Polarization-only bispectra display a significant improvement in robustness; they can now be used independently to set primordial NG constraints with a sensitivity comparable to WMAP temperature-based results and they give excellent agreement. In addition to the analysis of the standard local, equilateral, and orthogonal bispectrum shapes, we consider a large number of additional cases, such as scale-dependent feature and resonance bispectra, isocurvature primordial NG, and parity-breaking models, where we also place tight constraints but do not detect any signal. The non-primordial lensing bispectrum is, however, detected with an improved significance compared to 2015, excluding the null hypothesis at 3.5σ. Beyond estimates of individual shape amplitudes, we also present model-independent reconstructions and analyses of thePlanckCMB bispectrum. Our final constraint on the local primordial trispectrum shape isgNLlocal= (−5.8 ± 6.5) × 104(68% CL, statistical), while constraints for other trispectrum shapes are also determined. Exploiting the tight limits on various bispectrum and trispectrum shapes, we constrain the parameter space of different early-Universe scenarios that generate primordial NG, including general single-field models of inflation, multi-field models (e.g. curvaton models), models of inflation with axion fields producing parity-violation bispectra in the tensor sector, and inflationary models involving vector-like fields with directionally-dependent bispectra. Our results provide a high-precision test for structure-formation scenarios, showing complete agreement with the basic picture of the ΛCDM cosmology regarding the statistics of the initial conditions, with cosmic structures arising from adiabatic, passive, Gaussian, and primordial seed perturbations.

Bayesian Joint Modeling of Multiple Brain Functional Networks

Investigating the similarity and changes in brain networks under different mental conditions has become increasingly important in neuroscience research. A standard separate estimation strategy fails to pool information across networks and hence has reduced estimation accuracy and power to detect between-network differences. Motivated by an fMRI Stroop task experiment that involves multiple related tasks, we develop an integrative Bayesian approach for jointly modeling multiple brain networks that provides a systematic inferential framework for network comparisons. The proposed approach explicitly models shared and differential patterns via flexible Dirichlet process-based priors on edge probabilities. Conditional on edges, the connection strengths are modeled via Bayesian spike-and-slab prior on the precision matrix off-diagonals. Numerical simulations illustrate that the proposed approach has increased power to detect true differential edges while providing adequate control on false positives and achieves greater network estimation accuracy compared to existing methods. The Stroop task data analysis reveals greater connectivity differences between task and fixation that are concentrated in brain regions previously identified as differentially activated in Stroop task, and more nuanced connectivity differences between exertion and relaxed task. In contrast, penalized modeling approaches involving computationally burdensome permutation tests reveal negligible network differences between conditions that seem biologically implausible. Supplementary materials for this article, including a standardized description of the materials available for reproducing the work, are available as an online supplement.

동위원소 추적자를 이용한 수문곡선분리 및 정량적 기저유출 산정에 대한 고찰

최근 기후변화에 의한 강우 패턴 변화는 하천의 유출량 변화에 영향을 미치고 가뭄 및 홍수와 같은 자연재해의 위험성을 더욱 증가시키고 있다. 이러한 강우 패턴 변화는 하천의 유량뿐만 아니라 수질에도 영향을 미쳐 사회적, 경제적, 환경적인 측면에서 많은 문제를 유발하게 된다. 따라서, 안정적인 수자원 확보와 비점오염원 관리를 위해 하천 유량의 대부분을 차지하는 기저 유출을 관리하는 것은 매우 중요하다. 하지만, 기저 유출은 직접유출과 달리 직접적인 측정이 어려워 그 중요성에도 불구하고 그동안 많은 연구들에서 그 중요성이 간과되어 왔다. 본 논평에서는 기저 유출의 특성을 이해하기 위해 최근에 보편적으로 사용되는 ‘수문곡선분리(hydrograph separation)’에 대하여 설명하고 기존의 그래픽을 이용한 방법과 이를 바탕으로 개발된 모형에 대해 설명하였다. 그리고 동위원소 및 화학성분을 이용한 수문분리법을 2성분계와 3성분계로 나누어 설명하고 국내 연구사례들을 함께 제시하였다. 또한, 이러한 수문분리법을 실제 수계에 적용할 때 가장 크게 고려해야 할 사항인 단성분(end-member)과 그로 인해 발생하는 수문분리의 불확정성에 대해 설명하였다. 이러한 연구를 통해 실제수계에서 보존적 화학성분이나 동위원소를 추적자로 이용한 정량적 수문분리시 불확정성을 유발시키는 요인에 대한 추가적인 연구가 필요함을 강조하고자 하였다.

Impact on Nonfirearm Deaths of Firearm Laws Affecting Firearm Deaths: A Systematic Review and Meta-Analysis.

Background. There is debate whether policies that reduce firearm suicides or homicides are offset by increases in non-firearm-related deaths.Objectives. To assess the extent to which changes in firearm homicides and suicides following implementation of various gun laws affect nonfirearm homicides and suicides.Search Methods. We performed a literature search on 13 databases for studies published between 1995 and October 31, 2018 (PROSPERO CRD42019120105).Selection Criteria. We included studies if they (1) estimated an effect of 1 of 18 included classes of gun policy on firearm homicides or suicides, (2) included a control group or comparison group and evaluated time series data to establish that policies preceded their purported effects, and (3) provided estimated effects of the policy and inferential statistics for either total or nonfirearm homicides or suicides.Data Collection and Analysis. We extracted data from each study, including study timeframe, population, and statistical methods, as well as point estimates and inferential statistics for the effects of firearm policies on firearm deaths as well as either nonfirearm or overall deaths. We assessed quality at the estimate (study-policy-outcome) level by using prespecified criteria to evaluate the validity of inference and causal identification. For each estimate, we derived the mortality multiplier (i.e., the ratio of the policy's effect on total homicides or suicides; expressed as a change in the number of deaths) as a proportion of its effect on firearm homicides or suicides. Finally, we performed a meta-analysis to estimate overall mortality multipliers for suicide and homicide that account for both within- and between-study heterogeneity.Main Results. We identified 16 eligible studies (study timeframes spanning 1977-2015). All examined state-level policies in the United States, with most estimating effects of multiple policies, yielding 60 separate estimates of the mortality multiplier. From these, we estimated that a firearm law's effect on homicide, expressed as a change in the number of total homicide deaths, is 0.99 (95% confidence interval = 0.76, 1.22) times its effect on the number of firearm homicides. Thus, on average, changes in the number of firearm homicides caused by gun policies are neither offset nor compounded by second-order effects on nonfirearm homicides. There is insufficient evidence in the existing literature on suicide to indicate the extent to which the effects of gun policy changes on firearm suicides are offset or compounded by their effects on nonfirearm suicides.Authors' Conclusions. State gun policies that reduce firearm homicides are likely to reduce overall homicides in the state by approximately the same number. It is currently unknown whether the same holds for state gun policies that significantly reduce firearm suicides. The small number of studies meeting our inclusion criteria, issues of methodological quality within those studies, and the possibility of reporting bias are potential limitations of this review.Public Health Implications. Policies that reduce firearm homicides likely have large benefits for public health as there is little evidence to support a strong substitution effect between firearm and nonfirearm homicides at the population level. Further research is needed to determine whether policies that produce population-level reductions in firearm suicides will translate to overall declines in suicide rates.

Combustion Engine Test Bed System Identification Under the Presence of Cyclic Disturbances

In this article, a new approach for combustion engine test bed system identification is presented. Modern engine test beds are used to reduce development time by utilizing them for hardware-in-the-loop tests. For highly accurate and close-to-reality tests, model-based controllers are deployed, which rely on precise models of the test bed. Hereby, the main challenge is the unknown, cyclic disturbance of the engine due to compression and combustion of the air-fuel mixture. These disturbances also occur when the throttle is kept at zero and have a big impact on the measurements. Therefore, parameter estimation is strongly impeded. A method for dealing with these disturbances and embed them into the identification procedure in a two-step fashion is presented in this contribution. Further advantages of this new approach are that a physical model is obtained, but prior knowledge of parameters is not necessary. Moreover, disassembling of the test bed to perform separate parameter estimation is not needed and hence, the time consumption of the procedure is kept low. Experimental results on a 4-cylinder diesel engine test bed prove the feasibility and effectiveness of the proposed concepts.

Estimating outcome-specific effects in meta-analyses of multiple outcomes: A simulation study.

In meta-analysis, primary studies often include multiple, dependent effect sizes. Several methods address this dependency, such as the multivariate approach, three-level models, and the robust variance estimation (RVE) method. As for today, most simulation studies that explore the performance of these methods have focused on the estimation of the overall effect size. However, researchers are sometimes interested in obtaining separate effect size estimates for different types of outcomes. A recent simulation study (Park & Beretvas, 2019) has compared the performance of the three-level approach and the RVE method in estimating outcome-specific effects when several effect sizes are reported for different types of outcomes within studies. The goal of this paper is to extend that study by incorporating additional simulation conditions and by exploring the performance of additional models, such as the multivariate model, a three-level model that specifies different study-effects for each type of outcome, a three-level model that specifies a common study-effect for all outcomes, and separate three-level models for each type of outcome. Additionally, we also tested whether the a posteriori application of the RV correction improves the standard error estimates and the 95% confidence intervals. Results show that the application of separate three-level models for each type of outcome is the only approach that consistently gives adequate standard error estimates. Also, the a posteriori application of the RV correction results in correct 95% confidence intervals in all models, even if they are misspecified, meaning that Type I error rate is adequate when the RV correction is implemented.

Distilling the distinct contralateral and ipsilateral attentional responses to lateral stimuli and the bilateral response to midline stimuli for upper and lower visual hemifield locations.

A contralateral posterior negativity elicited by lateral oddballs (N2pc) and a bilateral posterior negativity elicited by vertical midline oddballs (bilateral N2) are ERP components reflecting attentional deployment that have been rarely compared. In different tasks, we explored to what extent they reflect similar underlying mechanisms of attention. We used a multiple-frame procedure to present pop-out color oddballs among distractors. A homogeneous condition contained only distractors (0 oddballs) and served as a control condition that was subtracted from oddball-present conditions to isolate attention effects. The number of oddballs and the vertical hemifield containing them (upper vs. lower) were two critical factors. For the lower hemifield, the signal amplitude increased with the number of oddballs, otherwise had similar effects and scalp distributions, suggesting the bilateral N2 acted as a bilateral N2pc and likely reflected similar underlying generators. For the upper hemifield, component amplitude also increased with the number of oddballs, but the scalp distributions were positive and more centered, suggesting inverted generators across the two vertical hemifields. An ipsilateral positivity occurred about 50ms after a contralateral positivity, similar in magnitude, producing a biphasic contra-minus-ipsi difference wave. Previously reported smaller negative N2pc components for upper hemifield oddballs likely reflected a negative lobe artificially created by the subtraction of a lagged positive ipsilateral response. The results compel us to argue for a systematic separation of data for upper versus lower hemifields in studies of visuo-spatial attention, and the use of an experimental design permitting the separate estimation of contralateral and ipsilateral responses.

N-terminal pro B-type natriuretic peptide (NT-proBNP): a possible surrogate of biological age in the elderly people

NT-proB-type natriuretic peptide (NT-proBNP) increases with age and is associated with all-cause mortality. With this study, we assessed its possible utilization as a marker of biological age in comparison with other variables. The study included 1079 non-institutionalized elderly subjects (mean age 72.8 ± 5.5 years, 561 women). Baseline measurements were performed of serum NT-proBNP and of some laboratory variables previously utilized to estimate biological age (creatinine, albumin, C-reactive protein, cholesterol, blood glucose, leukocytes, lymphocytes, hemoglobin, mean cell volume). During 7 years of follow-up, 114 all-cause deaths occurred. The logarithm of NT-proBNP was the most age-related parameter (r = 0.35, P < 0.0001). Its relationship with mortality, according to Cox regression and ROC curve (AUC = 0.707, 95% CI 0.654–0.759), was stronger than that of all other variables, including age. In multivariate analysis, only NT-proBNP and age remained independently associated with mortality. The regression lines between age and NT-proBNP (pg/ml) allowed a separate estimation of biological age (“proBNPage”) for men (= [log(NT-proBNP) + 1.2068]/0.0827) and for women (= [log(NT-proBNP) − 1.5258]/0.0478). The hazard ratio of all-cause mortality for the fifth quintile of proBNP age (≥ 85 years) compared with the first quintile (< 61 years) was 7.9 (95% CI 3.6–17.5). Similarly, the difference between pro-BNPage and chronological age was associated with a hazard ratio of 3.5 in the fifth quintile (95% CI 1.9–6.4) and was associated with disease count (P for trend = 0.0002). In conclusion, NT-proBNP was the best indicator of biological age, which can be estimated by simple formulas and might be used for prognostic purposes or as a surrogate end point in epidemiological and intervention studies.

Survival of Immature Gopher Tortoises Recruited into a Translocated Population

ABSTRACTPopulation manipulations such as translocation and head‐starting are increasingly used as recovery tools for chelonians. But evaluating success of individual projects can require decades of monitoring to detect population trends in these long‐lived species. Furthermore, there are often few benchmarks from stable, unmanipulated populations against which to compare demographic rates, particularly for the immature stages. We used 8 years of mark‐recapture data to estimate apparent survival of immature gopher tortoises (Gopherus polyphemus) recruited into an introduced population of gopher tortoises first established on St. Catherines Island, Georgia, USA, in 1987. During 2006–2013, we conducted targeted trapping of immature gopher tortoises and compared survival of the hatchling, juvenile and subadult stages among treatments: individuals released shortly after hatching from eggs obtained from gravid female founders (direct releases), individuals reared in captivity for 6–9 months following hatching (head‐starts), and individuals first encountered as free‐ranging, wild‐recruited offspring (wild recruits). Among the candidate models we examined, the best fit model included additive effects of tortoise stage and treatment; however, overlapping 95% credible intervals among treatments (CrI) suggested that survival did not vary significantly among treatments. Annual apparent survival increased over the immature period, highlighting the importance of calculating separate estimates for the different immature stages. Across all treatments, the additive model estimated annual apparent survival probability to be 0.37 (CrI = 0.25–0.48) for hatchlings, 0.71 (CrI = 0.61–0.81) for juveniles, and 0.83 (CrI = 0.74–0.94) for subadults. Our study, in combination with previous monitoring efforts at St. Catherines Island, provides strong evidence that the translocation and subsequent population augmentation efforts have been successful in establishing a robust population of gopher tortoises. Additionally, our results provide estimates of demographic rates for life stages that are poorly understood but critical to understanding population dynamics of this imperiled species. © 2020 The Wildlife Society.