Compulsory Pilotage in International Straits: The Torres Strait PSSA Proposal

At a time when the International Maritime Organisation's (IMO) Particularly Sensitive Sea Area (PSSA) concept is under intense scrutiny by IMO member states, Australia and Papua New Guinea jointly proposed an extension to the existing Great Barrier Reef PSSA to include the waters of the Torres Strait. As a measure to protect this PSSA, a compulsory pilotage regime was proposed for adoption by the IMO. This article analyzes the Torres Strait proposal and, in particular, the reaction by many IMO member states to the proposal for compulsory pilotage in a strait used for international navigation. Consideration is given to the legal basis for such a measure and the options available to the proposing states to implement a pilotage regime in the Torres Strait.     

Aspects of reproductive biology of curimba Prochilodus lacustris (Pisces,Prochilodontidae) in a tropical lake in Northeastern Brazil

This study evaluated the annual cycle of biological reproductive aspects of Prochilodus lacustris, a neotropical fish species, in Baixada Maranhense Protection Area in northeastern Brazil. Fish were collected monthly between June of 2015 and June of 2016 using gill nets. In the laboratory, 600 individuals were weighed, measured, and eviscerated to obtain biometric data and data for the microscopic and macroscopic analyses of the maturation stages of the gonads. These analyses allowed the determination of the reproductive period using biological indicators such as the gonadosomatic index and hepatosomatic index, condition factor, stomach repletion index, and spawning season. Abiotic variables were measured in situ during the samplig: temperature, pH, dissolved oxygen, and electrical conductivity. In addition, local rainfall data was also obtained. The results showed that the total body length of individuals varied from 151 to 211 mm in males, and from 142 to 239 mm in females. The sex ratio showed a predominance of females over males, and the species showed negative allometric growth. The annual variation of reproductive indicators and the frequency of individuals in advanced stages of gonadal maturation suggest that the reproductive cycle of the species occurs between November and January, with a reproductive peak in January. This reproductive peak coincides with the beginning of the region's rainy season. Although we did not do the fertility analysis, our results suggest that the species presents partitioned spawning. In conclusion, this results demonstrates that the reproduction of the investigated specie is influenced by associations between environmental variables on a seasonal scale and can be contribute to improve the understanding of the dynamics of the physiological reproductive process in lentic environments.     

Detecting successional changes in tropical forest structure using GatorEye drone-borne lidar

Drone-based remote sensing is a promising new technology that combines the benefits of ground-based and satellite-derived forest monitoring by collecting fine-scale data over relatively large areas in a cost-effective manner. Here, we explore the potential of the GatorEye drone-lidar system to monitor tropical forest succession by canopy structural attributes including canopy height, spatial heterogeneity, gap fraction, leaf area density (LAD) vertical distribution, canopy Shannon index (an index of LAD), leaf area index (LAI), and understory LAI. We focus on these variables’ relationship to aboveground biomass (AGB) stocks and species diversity. In the Caribbean lowlands of northeastern Costa Rica, we analyze nine tropical forests stands (seven second-growth and two old-growth). Stands were relatively homogenous in terms of canopy height and spatial heterogeneity, but not in their gap fraction. Neither species density nor tree community Shannon diversity index was significantly correlated with the canopy Shannon index. Canopy height, LAI, and AGB did not show a clear pattern as a function of forest age. However, gap fraction and spatial heterogeneity increased with forest age, whereas understory LAI decreased with forest age. Canopy height was strongly correlated with AGB. The heterogeneous mosaic created by successional forest patches across human-managed tropical landscapes can now be better characterized. Drone-lidar systems offer the opportunity to improve assessment of forest recovery and develop general mechanistic carbon sequestration models that can be rapidly deployed to specific sites, an essential step for monitoring progress within the UN Decade on Ecosystem Restoration.     

Comparison of lethal and non-lethal age-based growth estimation methodologies to assess an endemic bay population of Atlantic cod (Gadus morhua)

The Gilbert Bay, Labrador, MPA (Marine Protected Area) was created in 2005 to protect a genomically distinct and locally adapted bay resident population of Atlantic cod (Gadus morhua) from commercial overfishing. Since then research showed that significant numbers of individuals migrate beyond MPA boundaries creating a concern that fishing continues to impact this endemic population. As part of research and MPA monitoring to assess the health of the protected cod population, lethal sampling of Gilbert Bay cod was conducted from 1998 to 2009 to gather length-at-age data from otoliths. Since then only non-lethal sampling methods were used so as to help conserve the protected population. This study was conducted to compare non-lethally (mark-recapture and length-frequency) obtained age and growth data with lethally (otolith-length-at-age) obtained data. The three methods produced similar results for the 1998 to 2009 period, and both of the non-lethal methods considered were consistent over the 20 year study, confirming their preference over lethal methods for this small endemic fish population.     

“三生空间”视角下三峡库区土地利用转型的生态系统服务价值效应

明晰社会经济快速转型背景下的“三生空间”演变过程及其生态系统服务效应,对国土空间优化和区域可持续发展具有重要意义。以1980、2000、2018年土地利用遥感监测数据为基础,基于“三生空间”视角,采用地学信息图谱刻画了三峡库区土地利用转型过程,并通过生态系统服务贡献值测度了土地利用转型的生态环境效应。结果表明: 1980—2018年,三峡库区工业生产空间和生活空间面积不断增加,而农业生产空间和生态空间面积逐渐减少;从图谱转移视角分析,1980—2000年间,土地利用格局相对稳定,以未发生转移的图谱单元占主导,而2000—2018年土地利用转型复杂,以农业生产空间与林地、草地生态空间相互转化占主导,城镇化、工业化进程加快是导致农业生产空间、生态空间面积萎缩的主要原因;三峡库区生态系统服务价值在时间上呈先缓慢降低后迅速增加的趋势,在空间上呈“东部高-西部低”的分布特征;生态保护修复工程促进了生态系统服务价值正效应,但经济社会快速发展挤占了大量的农业生产空间、生态空间,加之农田复耕等行为在一定程度上导致了生态系统服务价值负效应。     

African Wild Dog Dispersal and Implications for Management

Successful conservation of species that roam and disperse over large areas requires detailed understanding of their movement patterns and connectivity between subpopulations. But empirical information on movement, space use, and connectivity is lacking for many species, and data acquisition is often hindered when study animals cross international borders. The African wild dog (Lycaon pictus) exemplifies such species that require vast undisturbed areas to support viable, self-sustaining populations. To study wild dog dispersal and investigate potential barriers to movements and causes of mortality during dispersal, between 2016 and 2019 we followed the fate of 16 dispersing coalitions (i.e., same-sex group of ≥1 dispersing African wild dogs) in northern Botswana through global positioning system (GPS)-satellite telemetry. Dispersing wild dogs covered ≤54 km in 24 hours and traveled 150 km to Namibia and 360 km to Zimbabwe within 10 days. Wild dogs were little hindered in their movements by natural landscape features, whereas medium to densely human-populated landscapes represented obstacles to dispersal. Human-caused mortality was responsible for >90% of the recorded deaths. Our results suggest that a holistic approach to the management and conservation of highly mobile species is necessary to develop effective research and evidence-based conservation programs across transfrontier protected areas, including the need for coordinated research efforts through collaboration between national and international conservation authorities. © 2020 The Wildlife Society.     

ROC curve inference for best linear combination of two biomarkers subject to limits of detection

The receiver operating characteristic (ROC) curve is a tool commonly used to evaluate biomarker utility in clinical diagnosis of disease. Often, multiple biomarkers are developed to evaluate the discrimination for the same outcome. Levels of multiple biomarkers can be combined via best linear combination (BLC) such that their overall discriminatory ability is greater than any of them individually. Biomarker measurements frequently have undetectable levels below a detection limit sometimes denoted as limit of detection (LOD). Ignoring observations below the LOD or substituting some replacement value as a method of correction has been shown to lead to negatively biased estimates of the area under the ROC curve for some distributions of single biomarkers. In this paper, we develop asymptotically unbiased estimators, via the maximum likelihood technique, of the area under the ROC curve of BLC of two bivariate normally distributed biomarkers affected by LODs. We also propose confidence intervals for this area under curve. Point and confidence interval estimates are scrutinized by simulation study, recording bias and root mean square error and coverage probability, respectively. An example using polychlorinated biphenyl (PCB) levels to classify women with and without endometriosis illustrates the potential benefits of our methods.     

Accurate determination of the structural elasticity of human hair by a small-scale bending test

This paper reports on a small-scale bending method for human hair. The test sample, which is elliptical in cross-section, is fixed to a hollow steel needle using resin to form a cantilever. A loading probe is used to subject this to a lateral load, where the load is applied parallel to either the long or short axis of the elliptical cross-section. From these tests, load-displacement relationships for the hair were obtained. From the experimental data and analysis, we found that the structural elasticity determined is independent of the direction of bending, and precise measurements of the structural elasticity of human hair with scattering of less than 5% were realized using this test scheme. Finally, changes in the structural elasticity of hair due to hair treatments were detected and the changes are discussed based on a theoretical model of the multi-layered structure.     

Robust Estimation of Area Under ROC Curve Using Auxiliary Variables in the Presence of Missing Biomarker Values

Summary In medical research, the receiver operating characteristic (ROC) curves can be used to evaluate the performance of biomarkers for diagnosing diseases or predicting the risk of developing a disease in the future. The area under the ROC curve (ROC AUC), as a summary measure of ROC curves, is widely utilized, especially when comparing multiple ROC curves. In observational studies, the estimation of the AUC is often complicated by the presence of missing biomarker values, which means that the existing estimators of the AUC are potentially biased. In this article, we develop robust statistical methods for estimating the ROC AUC and the proposed methods use information from auxiliary variables that are potentially predictive of the missingness of the biomarkers or the missing biomarker values. We are particularly interested in auxiliary variables that are predictive of the missing biomarker values. In the case of missing at random (MAR), that is, missingness of biomarker values only depends on the observed data, our estimators have the attractive feature of being consistent if one correctly specifies, conditional on auxiliary variables and disease status, either the model for the probabilities of being missing or the model for the biomarker values. In the case of missing not at random (MNAR), that is, missingness may depend on the unobserved biomarker values, we propose a sensitivity analysis to assess the impact of MNAR on the estimation of the ROC AUC. The asymptotic properties of the proposed estimators are studied and their finite‐sample behaviors are evaluated in simulation studies. The methods are further illustrated using data from a study of maternal depression during pregnancy.     

英国景观特征评估体系与我国风景名胜区评价体系的比较研究

在回顾英国景观特征评估体系产生和演化背景的基础上,分析了景观特征等概念,研究了景观特征评估体系在英国法定自然美景区中的应用,并将其特点归纳为价值中立和尺度分级、多样化的景观特征提取、单独分离的决策过程3个方面;同时将LCA景观特征评估体系与我国风景名胜区中广泛应用的风景资源评价体系进行了比较,结合我国风景名胜区发展的现状,提出我国可以在景观遗产价值的评估、景观遗产可持续发展概念的再认识、公众参与制度的进一步完善3个方面借鉴景观特征评估体系的经验。