机场周边家鸽飞行行为的潜在鸟击风险初步研究

鸟击防控是一个世界性难题。家鸽（Columba livia domestica）是机场生物多样性调查中最常见鸟类,也是历史上鸟击高危物种之一,还是唯一由于人工大量放飞导致严重鸟击事故的物种。2020年9月至2021年1月,在我国4个机场,针对机场周边23家鸽户,共149只家鸽开展卫星追踪放飞实验研究,获得了家鸽个体在机场周边的飞行时间、飞行距离、飞行高度等个体运动参数。研究发现,1）单次放飞时长多在1 ~ 4 h,单次平均放飞时长为（2.9 ± 1.6）h。在鸽户自主放飞家鸽和家鸽自由回笼的动态过程中,下午活动在外的家鸽数量较多,尤其15:00 ~ 17:59时段是活动在外家鸽数量最多的时段。2）飞行距离多在3.0 km范围内,最远可达8.9 km;存在家鸽飞行范围覆盖机场现象的鸽户占比45%。3）飞行高度主要在200 m及以下,平均飞行高度为（29 ± 28）m。本研究结果表明,下午,尤其是15:00 ~ 17:59时段应作为家鸽防控的重点时段,机场周边10 km以及高度0 ~ 200 m的范围应作为家鸽防控的重点空间范围。根据《中华人民共和国民用航空法（2021修正）》第五十八条明确规定“不得饲养、放飞影响飞行安全的鸟类动物和其他物体”,需要建立相应的问责机制、加强有效监管,以降低家鸽鸟击风险。     

Observations and tracking of killer whales (Orcinus orca) with shore‐based X‐band marine radar at a marine energy test site

The Atlantic killer whale (Orcinus orca) is a top‐level marine predator with a global range, being found in all of Earth's oceans. The potential interaction between killer whales and marine renewable energy projects requires surveillance and monitoring efforts that call for new technologies, with marine radar showing promise in the field. Marine radar images recorded at the European Marine Energy Centre (EMEC) were used to track a pair of male killer whales undertaking Surface Active Behavior (SAB) with visual observations used as validation. Using a tidal prediction model, the tide‐adjusted, radar‐derived target speeds between SAB events provide estimates of swim speeds averaging 4 m/s and time between SAB events of 30 s. The similarities between the radar signatures of the animals and sea clutter, combined with their low occurrence compared to other imaged phenomena renders automatic detection with this system difficult. However, the combination of opportunistic radar imagery and independent visual observation has allowed the radar signature of one form of killer whale SAB to be documented. It is hoped that with a greater number of validated observations such as these that automated, radar‐based identification and the benefits it will bring to long‐term observations at MRE sites will be possible.     

细菌显微追踪技术在生物被膜中的应用

细菌生物被膜是粘附于物体表面的由细菌细胞及其胞外物质组成的复杂膜样物聚集体,具有很强的耐药性和免疫逃逸能力。生物被膜内细菌的代谢活性、运动状态等与浮游细菌有明显区别。近年来,先进的显微成像技术结合新型图像处理方法,在研究细菌的运动、生理等方面发挥了重要作用。本文围绕生物被膜,概述了细菌显微追踪技术在其研究中的应用。主要从细菌的运动方式和生物被膜形成过程的调控两方面出发,介绍了在单细胞水平上利用该技术研究生物被膜的进展,包括细菌的游泳、蹭行、群集运动和多种信号通路调控下生物被膜的形成过程等,并展望了该技术在生物被膜其他相关研究领域的应用前景。     

鄂尔多斯蓑羽鹤小群体的GPS-GSM跟踪初步分析

在内蒙古鄂尔多斯遗鸥国家级自然保护区已多次发现有一个孤立的蓑羽鹤(Anthropoides virgo)小种群在此地繁殖和度夏。2015年7月,在该地区为5只成年蓑羽鹤(3只繁殖,2只非繁殖)佩戴了中国湖南生产的GPS-GSM发射器。截止到5只蓑羽鹤全部离开鄂尔多斯高原,共获得7 794个GPS位点信息。通过跟踪信息了解到1只个体在9月18日死于鄂尔多斯高原的中西部,其余个体于9月末至10月初先后迁出鄂尔多斯高原。迁徙过程中的最快瞬时速度为93.1 km/h。4只个体迁出鄂尔多斯高原的时间和路线均略有不同。     

Speed profiles in wheelchair court sports; comparison of two methods for measuring wheelchair mobility performance

Wheelchair mobility performance is an important aspect in most wheelchair court sports, commonly measured with an indoor tracking system or wheelchair bound inertial sensors. Both methods provide key wheelchair mobility performance outcomes regarding speed. In this study, we compared speed profiles of both methods to gain insight into the level of agreement, for recommendations regarding future performance measurement.Data were obtained from 5 male highly trained wheelchair basketball players during match play. Players were equipped simultaneously with a tag on the footplate for the indoor tracking system (∼8 Hz) and inertial sensors on both wheels and frame (199.8 Hz). Being part of a larger study on 3 vs 3 player game formats, data were collected in several matches with varying field sizes, but activity profiles closely resembled regular match play. Both systems provide similar outcomes regarding distance covered and average speed. Due to differences in sampling frequency and sensor location (reference point) on the wheelchair (for speed calculation), minor differences were revealed at low speeds (<2.5 m/s). Since both systems provide complementary features, a hybrid solution as proved feasible in this study, could possibly serve as the new gold standard for mobility performance measurement in wheelchair basketball or wheelchair court sports in general.     

Accuracy map of an optical motion capture system with 42 or 21 cameras in a large measurement volume

Optical motion capture is commonly used in biomechanics to measure human kinematics. However, no studies have yet examined the accuracy of optical motion capture in a large capture volume (>100 m³), or how accuracy varies from the center to the extreme edges of the capture volume. This study measured the dynamic 3D errors of an optical motion capture system composed of 42 OptiTrack Prime 41 cameras (capture volume of 135 m³) by comparing the motion of a single marker to the motion reported by a ThorLabs linear motion stage. After spline interpolating the data, it was found that 97% of the capture area had error below 200 μm. When the same analysis was performed using only half (21) of the cameras, 91% of the capture area was below 200 μm of error. The only locations that exceeded this threshold were at the extreme edges of the capture area, and no location had a mean error exceeding 1 mm. When measuring human kinematics with skin-mounted markers, uncertainty of marker placement relative to underlying skeletal features and soft tissue artifact produce errors that are orders of magnitude larger than the errors attributed to the camera system itself. Therefore, the accuracy of this OptiTrack optical motion capture system was found to be more than sufficient for measuring full-body human kinematics with skin-mounted markers in a large capture volume (>100 m³).     

Intravital multiphoton photoconversion with a cell membrane dye

Photoconversion, an irreversible shift in a fluorophore emission spectrum after light exposure, is a powerful tool for marking cellular and subcellular compartments and tracking their dynamics in vivo. This paper reports on the photoconversion properties of Di‐8‐ANEPPS, a commercially available membrane dye. When illuminated with near‐infrared femtosecond laser pulses, Di‐8‐ANEPPS undergoes multiphoton photoconversion as indicated by the supralinear dependence of the conversion rate ρ_pc on the incident power (), and by the ability to photoconvert a thin optical section in a three‐dimensional matrix. The characteristic emission spectrum changed from red to blue, and ratiometric analysis on single cells in vitro revealed a 65‐fold increase in the blue to red wavelength ratio after photoconversion. The spectral shift is preserved in vivo for hours, making Di‐8‐ANEPPS a useful dye for intravital cell marking and tracking applications.

     

Early‐life foraging: Behavioral responses of newly fledged albatrosses to environmental conditions

In order to survive and later recruit into a population, juvenile animals need to acquire resources through the use of innate and/or learnt behaviors in an environment new to them. For far‐ranging marine species, such as the wandering albatross Diomedea exulans, this is particularly challenging as individuals need to be able to rapidly adapt and optimize their movement strategies in response to the highly dynamic and heterogeneous nature of their open‐ocean pelagic habitats. Critical to this is the development and flexibility of dispersal and exploratory behaviors. Here, we examine the movements of eight juvenile wandering albatrosses, tracked using GPS/Argos satellite transmitters for eight months following fledging, and compare these to the trajectories of 17 adults to assess differences and similarities in behavioral strategies through time. Behavioral clustering algorithms (Expectation Maximization binary Clustering) were combined with multinomial regression analyses to investigate changes in behavioral mode probabilities over time, and how these may be influenced by variations in day duration and in biophysical oceanographic conditions. We found that juveniles appeared to quickly acquire the same large‐scale behavioral strategies as those employed by adults, although generally more time was spent resting at night. Moreover, individuals were able to detect and exploit specific oceanographic features in a manner similar to that observed in adults. Together, the results of this study suggest that while shortly after fledging juvenile wandering albatrosses are able to employ similar foraging strategies to those observed in adults, additional skills need to be acquired during the immature period before the efficiency of these behaviors matches that of adults.     

How general are global trends in biotic homogenization? Floristic tracking in Chile,South America

Aim   To quantify the occurrence of floristic change in the vascular flora of Chile. We test whether continental areas have experienced floristic modification leading to either homogenization, differentiation or tracking.
Location   Continental Chile.
Methods   On the basis of the geographical distribution of native (1806 species) and naturalized plants (552 species) in continental Chile, we quantified change between two floristic stages: (1) pre-European flora, including native extant and extinct species; and (2) current flora, including native and naturalized species, but excluding extinct plants. We compared changes in compositional similarity (calculated by Jaccard's index, Δ J ) between pairs of regions, and similarity decay with respect to geographical distance. Additionally, by means of Whittaker's index, we examined species turnover, distinguishing between native and naturalized plants.
Results   Between floristic stages (pre-European vs. current flora) no significant changes in floristic similarity were noted at national or regional scales. Similarity decay showed no statistical differences between pre-European and current flora. Analysing patterns of geographical turnover, we found that species turnover of naturalized plants over their geographical range is similar to that of native plants.
Conclusions   The composition of the continental flora of Chile does not show significant modifications in similarity patterns after considering naturalized species, thus indicating floristic tracking. The causes of this phenomenon may be related to the current geographical distribution of naturalized plants, which closely parallels that of native plants. Our results differ from those obtained in Northern Hemisphere continents, thus indicating that trends of biotic change may differ between hemispheres.     

Seasonal distribution and dive behaviour of harp seals (<Emphasis Type="Italic">Pagophilus groenlandicus</Emphasis>) of the White Sea–Barents Sea stock

Eight adult female harp seals (Pagophilus groenlandicus) of the White Sea–Barents Sea stock were tagged with satellite-linked dive recorders during the nursing period and followed from breeding in late February 1995 until moulting in late April 1995. Another ten adult harp seals of both sexes were tagged and followed from moult in early May 1996 until breeding in late February the following year. Between breeding and moult the seals were distributed along the coasts of Kola of Russia and eastern Finnmark of Norway, coinciding in time and space with the spawning capelin (Mallotus villosus). Between moulting and breeding they encircled the entire Barents Sea, mostly in open water, using the water column from 20 to 300 m, and in so doing by and large reflecting the annual migrations of the capelin. Capelin is therefore assumed to be the main source of prey for the White Sea–Barents Sea stock of harp seals, to be substituted, in part, by amphipods (e.g. Themisto libellula) in mid-summer and polar cod (Boreogadus saida) and herring (Clupea pallasii) in late autumn and winter. These data provide a baseline for the evaluation of the effects of future climatic change in the rich Barents Sea ecosystem.