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61.
Objective
To examine the impact of the fetal fraction (FF) on the screen-positive rate in screening for microdeletion 22q11.2.Methods
This study is based on samples that were analyzed using the Harmony® Prenatal Test (Roche Inc). The study cohort comprised samples from women with singleton pregnancies who were at least 16 years old and at least at 11 weeks' gestation. Logistic regression analysis was used to determine significant covariates that carry an impact on the screen-positive rate.Results
The study population consisted of 52,019 pregnancies, including 309 pregnancies with a high-risk result for microdeletion 22q11.2. Thus, the overall screen-positive rate was 0.59%. In the low-risk group, the FF was 10.1%, and in the high-risk group, it was 7.3%. Regression analysis indicated a strong correlation between the FF and the screen-positive rate. In the cases with an FF of <11.0%, the screen-positive rate was 0.92%, while it was 0.13% in the group with a higher FF.Conclusion
The screen-positive rate depends on the FF. In order to keep the rate low, we recommend restricting the analysis to samples with a FF of 11% and more. 相似文献62.
Oliver Manlik Robert C. Lacy William B. Sherwin Hugh Finn Neil R. Loneragan Simon J. Allen 《Conservation biology》2022,36(4):e13897
Human-caused mortality of wildlife is a pervasive threat to biodiversity. Assessing the population-level impact of fisheries bycatch and other human-caused mortality of wildlife has typically relied upon deterministic methods. However, population declines are often accelerated by stochastic factors that are not accounted for in such conventional methods. Building on the widely applied potential biological removal (PBR) equation, we devised a new population modeling approach for estimating sustainable limits to human-caused mortality and applied it in a case study of bottlenose dolphins affected by capture in an Australian demersal otter trawl fishery. Our approach, termed sustainable anthropogenic mortality in stochastic environments (SAMSE), incorporates environmental and demographic stochasticity, including the dependency of offspring on their mothers. The SAMSE limit is the maximum number of individuals that can be removed without causing negative stochastic population growth. We calculated a PBR of 16.2 dolphins per year based on the best abundance estimate available. In contrast, the SAMSE model indicated that only 2.3–8.0 dolphins could be removed annually without causing a population decline in a stochastic environment. These results suggest that reported bycatch rates are unsustainable in the long term, unless reproductive rates are consistently higher than average. The difference between the deterministic PBR calculation and the SAMSE limits showed that deterministic approaches may underestimate the true impact of human-caused mortality of wildlife. This highlights the importance of integrating stochasticity when evaluating the impact of bycatch or other human-caused mortality on wildlife, such as hunting, lethal control measures, and wind turbine collisions. Although population viability analysis (PVA) has been used to evaluate the impact of human-caused mortality, SAMSE represents a novel PVA framework that incorporates stochasticity for estimating acceptable levels of human-caused mortality. It offers a broadly applicable, stochastic addition to the demographic toolbox to evaluate the impact of human-caused mortality on wildlife. 相似文献
63.
Oliver Behr Mirjam Knörnschild Otto von Helversen 《Behavioral ecology and sociobiology》2009,63(3):433-442
In many animal species, individuals compete for resources but avoid escalated conflicts by threat displays, i.e. a mutual
signalling behaviour that enables the opponents to predict the outcome of the conflict without the necessity of actual fighting.
For example, territory holders may use acoustic signals to communicate not only their own identity and the borders of their
territory but also their competitive quality, fighting ability and motivation. Here, we show that male sac-winged bats, Saccopteryx bilineata, adjust their vocal territorial displays according to the fundamental frequency of territorial songs of their opponents.
In playback experiments with territorial males, low-frequency stimuli elicited a higher territorial song rate and length than
high-frequency stimuli. Male S. bilineata that sing more often and with lower fundamental frequencies have been shown to sire more offspring than their competitors.
Fundamental frequency of territorial songs, hence, may reveal male quality and, consequently, the resulting threat posed to
competing males. We argue that this is reflected in the increased response of competitors to low-frequency territorial songs
shown here. Such competitive signalling behaviour has been shown in a few mammal species like red deer and baboons but, thus
far, not in bats.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
64.
The scallop fisheries off the southeast coast of Ireland have historically been considered a valuable resource for coastal communities, and hence their management is important. The scallop fishing grounds consist of a number of scallop beds dispersed throughout the St George's Channel and the southern Irish Sea. The boundaries between stocks and the interconnection in populations of adult scallops, through larval transport, is generally unknown. Until the time of this research, the stocks of scallop in this region had not been assessed. A research project was undertaken to develop novel, spatially explicit and multi-disciplinary approaches to the assessment of the scallop fisheries in the region. The project supported research in three related areas under the broad objective of developing stock assessment protocols and methods in order to promote sustainable management of these fisheries. One of these areas was the development and application of numerical models. The objectives of this modelling research were: (a) to reconstruct the physical environment of the study area; (b) investigate how this environment affects the demographics and nature of scallop; and (c) determine migration-transport pathways of the scallop larvae. From these investigations, light is shed on how the spatial variability in certain parameters of the natural environment determine habitats and the scallop populations. Also, the investigations now enable determinations to be made on the interconnectivities of 'disparate' scallop beds and where larvae are, in general, likely to be found. Thus, through the use of complex computer models, important clues are deduced that enable us to now understand key behavioural components of scallop larvae and their transport pathways. The analysis of these clues is assisting the development of protocols for managing the fish stock in a sustainable manner. 相似文献
65.
Although microbial transformations via cometabolism have been widely observed, the few available kinetic models of cometabolism have not adequately addressed the case of inhibition from both the growth and nongrowth substrates. The present study investigated the degradation kinetics of self-inhibitory growth (phenol) and nongrowth (4-chlorophenol, 4-CP) substrates, present individually and in combination. Specifically, batch experiments were performed using an Acinetobacter isolate growing on phenol alone and with 4-CP present. In addition, batch experiments were also performed to evaluate the transformation of 4-CP by resting, phenol-induced Acinetobacter cultures. The Haldane kinetic model adequately predicted the biodegradation of phenol alone, although a slight discrepancy was noted in cases of higher initial phenol concentrations. Similarly, a Haldane model for substrate utilization was also able to describe the trends in 4-CP transformation by the resting cell cultures. The 4-CP transformation by the Acinetobacter species growing on phenol was modeled using a competitive kinetic model of cometabolism, which included growth and nongrowth substrate inhibition and cross-inhibition terms. Excellent agreement was obtained between the model predictions using experimentally estimated parameter values and the experimental data for the synchronous disappearance of phenol and 4-CP. 相似文献
66.
Diphenylamine and derivatives in the environment: a review 总被引:3,自引:0,他引:3
Drzyzga O 《Chemosphere》2003,53(8):809-818
Diphenylamine (DPA) is a compound from the third European Union (EU) list of priority pollutants. It was assigned by the EU to Germany to assess and control its environmental risks. DPA and derivatives are most commonly used as stabilizers in nitrocellulose-containing explosives and propellants, in the perfumery, and as antioxidants in the rubber and elastomer industry. DPA is also widely used to prevent post-harvest deterioration of apple and pear crops. DPA is a parent compound of many derivatives, which are used for the production of dyes, pharmaceuticals, photography chemicals and further small-scale applications. Diphenylamines are still produced worldwide by the chemical industries. First reports showed that DPA was found in soil and groundwater. Some ecotoxicological studies demonstrated the potential hazard of various diphenylamines to the aquatic environment and to bacteria and animals. Studies on the biodegradability of DPA and its derivatives are very sparse. Therefore, further investigation is required to determine the complete dimension of the potential environmental hazard and to introduce possible (bio)remediation techniques for sites that are contaminated with this class of compounds. This is the first detailed review on DPA and some derivatives summarizing their environmental relevance as it is published in the literature so far and this review will recommend conducting further research in the future. 相似文献
67.
Future Taxonomic Partnerships: Reply to Goldstein 总被引:1,自引:0,他引:1
68.
ABSTRACT A major barrier to realising biofuels’ climate change mitigation potential is uncertainty concerning carbon emissions from indirect land use change (ILUC). Central to this uncertainty is the extent to which yields can respond dynamically to increased demand for agricultural commodities. This study examines the elasticity of soybean and corn yields in the USA for 1990–2017 using Bayesian network models to robustly quantify uncertainty. The central finding is that a single parameter value for yield elasticity does not adequately represent the effects of technology, policy and price pressures through time. The models demonstrate the limiting role of technological progress as well as farmers’ capital investment in response to system shocks. Results suggest evaluation of parameter uncertainty alone is unlikely to capture a full range of future ILUC scenarios and reiterate the need for ILUC studies to use probabilistic approaches as standard to robustly inform climate change mitigation policies. 相似文献
69.
Bettina Wachter Oliver P. Höner Marion L. East Waltraud Golla Heribert Hofer 《Behavioral ecology and sociobiology》2002,52(4):348-356
Avian models of facultative siblicide predict that rates of sibling aggression and the incidence of siblicide should be lower in prey-rich than prey-poor environments, and that siblicide should only occur when fitness benefits outweigh costs. We tested these predictions by comparing data from spotted hyena (Crocuta crocuta) twin litters in the Ngorongoro Crater, Tanzania, a habitat with a high density of resident prey (176 animals/km2) with similar data from the adjacent Serengeti National Park where density of resident prey is low (3.3 animals/km2). As predicted, rates of sibling aggression in Crater twin litters were substantially lower than those among twin siblings in the Serengeti. There was no evidence of siblicide in the Crater, in contrast to the Serengeti, where facultative siblicide occurs frequently. The growth rate of Crater cubs in singleton litters was similar to that of cubs in twin litters, whereas the growth rate of Serengeti singletons was higher than that of cubs in twin litters. Thus despotic behavior by dominant Crater cubs was unlikely to provide fitness benefits, while dominant Serengeti cubs that eliminated their sibling benefited from increased growth and enhanced survival. Previous studies have demonstrated biases in the sex-composition of hyena litters due to facultative siblicide. No such biases were apparent in Crater litters. Our results provide strong evidence that levels of sibling aggression in spotted hyenas are adjusted in an adaptive manner, and that siblicide is facultative and resource dependent. Our results do not support the idea of pre-natal manipulation of offspring sex by female spotted hyenas in response to changes in resource abundance. 相似文献
70.