Light-Dependent Magnetoreception in Birds: Does Directional Information Change with Light Intensity?

 Magnetic compass orientation in birds is based on light-dependent processes, with magnetoreception being possible only under light containing blue and green wavelengths. To look for possible intensity-dependent effects we tested Australian silvereyes during autumn migration under monochromatic green light (565 nm) produced by light-emitting diodes at various light levels. At intensities of 0.0021 and 0.0075 W/m², the birds showed normal activity and were oriented in their seasonally appropriate migratory direction. Under low light of 0.0002 W/m² the birds were less active; scatter increased, but they still oriented in their migratory direction. Under a high light level of 0.0150 W/m², however, the test birds showed a counterclockwise shift in direction, preferring west-northwest instead of north. This change in behavior may reflect a change in the output of the magnetoreception system, resulting from a disruption of the natural balance between the wavelengths of light. Received: 18 June 1999 / Accepted in revised form: 20 September 1999     

“功能眼镜”Yes or no

“防辐射眼镜,上网必备的护目镜”、“渐进多焦点、OK镜可以矫正近视”、 “美瞳让你眼睛更美丽”……炎炎夏日里,价格不菲的“功能眼镜”贴着高科技产品的标签,颇吸引人的眼球.它们果真有如此神奇功效吗?是概念炒作还是科技进步?是为人们服务还是为人民币服务?不明就里的你,出手要三思啊!     

Science as a “fixed point”? Quantification and boundary objects in international climate politics

Our understanding of climate change is dominated by quantified scientific knowledge, with science and politics usually seen as operating separately and autonomously from one another. By investigating a particular fact box in the IPCC’s Fourth Assessment Report (AR4), this paper challenges the assumption that science and policy can be clearly delineated. The so-called “Bali Box” gained a prominent role in negotiations leading up to the Copenhagen Conference in 2009, as it was widely seen as providing a “fixed point” – a quantified scientific answer to the question of equitable effort-sharing between North and South. This understanding of the Bali Box triggered a backlash, however, when the hybrid character of the box as an assemblage of science, political considerations and moral judgements became evident to actors in the negotiations. The paper employs the notion of boundary objects to analyse the history of the Bali Box, and argues that climate politics will benefit from a richer understanding of the interplay between science and policy. Moving beyond characterizations that place the Bali Box on either side of a clear boundary between the scientific and the political, we suggest focusing instead on what the Box as a hybrid product is doing, i.e. how it simplifies and quantifies, what it covers and what it leaves outside.     

Living in a “stethoscope”: burrow-acoustics promote auditory specializations in subterranean rodents

Subterranean mammals rely to a great extent on audition for communication and to be alerted to danger. The only hitherto published report on burrow acoustics revealed that in tunnels of blind mole-rats (Spalax ehrenbergi), airborne sounds of 440 Hz propagated best whereas lower and higher frequencies were effectively attenuated. Morpho-functional analyses classify the ear of subterranean mammals as a low-sensitivity and low-frequency device. Concordantly, hearing is characterized by low sensitivity and a restricted frequency range tuned to low frequencies (0.5–4 kHz). Some authors considered the restricted hearing in subterranean mammals vestigial and degenerate due to under-stimulation. In contrast to this view stand a rich (mostly low-frequency) vocal repertoire and progressive structural specializations of the middle and inner ear. Thus, other authors considered these hearing characteristics adaptive. To test the hypothesis that acoustical environment in burrows of different species of subterranean mammals is similar, we measured sound attenuation in burrows of Fukomys mole-rats (formerly known as Cryptomys, cf. Kock et al. 2006) of two differently sized species at different locations in Zambia. We show that in these burrows, low-frequency sounds (200–800 Hz) are not only least attenuated but also their amplitude may be amplified like in a stethoscope (up to two times over 1 m). We suggest that hearing sensitivity has decreased during evolution of subterranean mammals to avoid over-stimulation of the ear in their natural environment. We dedicate this work to Mathias Kawalika, who died in March 2006.     

Astaxanthin and papilioerythrinone in the skin of birds: a chromatic convergence of two metabolic routes with different precursors?

Carotenoids are organic pigments involved in several important physiological functions and may serve as indicators of individual quality in animals. These pigments are only obtained by animals from the diet, but they can be later transformed into other carotenoids by specific enzymatic reactions. The diet of farm-reared and probably wild red-legged partridges (Alectoris rufa) is mainly based on cereals that contain high levels of lutein and zeaxanthin. These two carotenoids are also predominant in internal tissues and blood of red-legged partridges. However, in their integuments, astaxanthin and papilioerythrinone (the last one identified in this work) are mainly present in their free form and esterified with fatty acids. According to available literature about carotenoid metabolism in animals, we propose that astaxanthin (λ _max?=?478 nm) and papilioerythrinone (λ _max?=?452–478 nm) are the result of a chromatic convergence of the transformation of dietary zeaxanthin and lutein, respectively. Moreover, the results obtained in this work provide the first identification by liquid chromatography coupled to accurate mass quadrupole time-of-flight mass spectrometer system of papilioerythrinone (m/z 581.3989 [M?+?H]⁺) in the skin (i.e., not feathers) of a vertebrate. Astaxanthin and papilioerythrinone are very close in terms of chemical structure and coloration, and the combination of these two keto-carotenoids is responsible for the red color of the ornaments in red-legged partridges.     

“化”:必由之路

有一假日,携妻女出游天河城。天空中雾气沉沉,空气中可闻到浓浓的工业烟味。走到天河体育中心门口欲过地道,见一字排开十个少男少女,每个人身上一个字,连起来读为: “让广州的天空明亮起来”深为所动。问之。原来是我们中山大学信息管理系的学生自发组织的。这件事,一直在我脑海里,使我久久不能忘记并且经常想起。有一次,一位广州市的领导问我:“我们广州市的环境污染到底到了什么样的程度?”我告诉他:“如果你鼻子能闻到、眼睛能看到的污染,那一定是     

The crux with reducing emissions in the long-term: The underestimated “now” versus the overestimated “then”

Mitigation and Adaptation Strategies for Global Change - The focus of this perspective piece is on memory, persistence, and explainable outreach of forced systems, with greenhouse gas (GHG)...     

朱伟业:“垃圾堆”里当“导游”

正他原本学习金融专业,却经过自学成为了环保工程师。他原本从事管理工作,却通过考试拿到了专业导游证。因而,谈技术原理,谈运营操作,他可以头头是道;讲环境教育,讲公益科普,他也能娓娓道来。他就是朱伟业,瀚蓝绿电固废处理(佛山)有限公司(以下简称瀚蓝绿电)社会责任部负责人。如今,作为企业届开展环境科普教育的一面旗帜,瀚蓝绿电已是名声在外;而朱伟业作为这面旗帜上的一点星辉,也是熠熠生光。     

环境保护:社会“安定剂”

近年来,环境污染成了影响社会稳定的一个新因素,一些地方群众因此上访。但是,曾以上访闻名的安徽省利辛县,近年未发生一起因环境污染导致的群众上访事件。前些年利辛县却不是这样,利辛人至今还记得,1994年～1995年,利辛县化工总厂生产小氮肥产生的有毒有害废水未经处理,明沟排经周围的朱瓦房行政村,致使该村1000多     

林兆铭:央视“朗读者” 动物“守护神”

他谈不上俊朗帅气、高大威猛,也没有超强的气场、耀眼的光环,但是在央视《朗读者》的舞台上,他却用自己的付出和坚守,赢得了全场的掌声与尊重。他就是来自广州野生动物救护中心的林兆铭。     

湖南日报:“雾霾费”需要“明白账”

正收雾霾费是本着谁污染谁负责的原则,用价格杠杆来治理企业排污。看起来抓住了要害,但实际上公众疑虑还是不少。检索早在1987年发布的《大气污染防治法》,2003年发布的《排污费征收使用管理条例》等法律条款不难发现,这种治理手段并不新鲜。但,为何近年来重污染天气却越来越猖狂?此外,数据显示,2003年至2013年,我国累计征收排污费1700     

刘东升:“公安利刃”变“环保尖兵”

<正>他,从警8年,2013年8月,义无反顾地从公安队伍加入生态环境部门。虽脱下警服,但他依旧一片丹心、心系群众,带领执法队伍敢于碰硬,严打环境违法犯罪,以实际行动从一把"公安利刃"转变为一名"环保尖兵",因表现突出,多次被评为省、市级先进工作者。他,就是东莞市生态环境局横沥分局副局长刘东升。     

预防环境灾难:“补牢”还是“补偿”

标题上的这个问题是我反思广西龙江河镉污染事件后的个人观点。1989-1995年,我在广西河池工作,也走访了柳州及其邻近地区。我喜爱河池,爱她的人民和田园风貌,她就像还没有商业化旅游前的桂林。河池在我脑海中留下了不可磨灭的印象,当我阅读到最近的环境灾难事件后,两幅画面立刻涌入脑海:清澈的水从石灰岩洞流入潺潺溪流、河流,突然间,新来了一群     

Climate change,adaptive capacity and policy direction in the Canadian North: Can we learn anything from the collapse of the east coast cod fishery?

Scientific evidence gathered over the past five years suggests that northern Canada and the Arctic have undergone, and are undergoing, formidable environmental changes linked to global climate change. Environmental change in the north is expected to persist and intensify over the course of the next century. When large-scale environmental changes take place, they inevitably affect people, especially when the cultures and livelihoods of those people depend on their relationship with the environment. Managing the local impacts of these changes is a matter of adaptation. This paper discusses some of the policy implications of adaptation––government interventions aiming to build communities’ and regions’ capacities to adapt to environmental changes. Three arguments for adaptive capacity building interventions in the north are discussed, and these arguments are augmented by a comparative review of government reactions to the collapse of the cod fishery in Atlantic Canada. Reactive and proactive policy approaches are discussed, and it is suggested from the comparison that proactive approaches to intervention are desirable for building adaptive capacity.

Tracking pigeons in a magnetic anomaly and in magnetically “quiet” terrain

Pigeons were released at two sites of equal distance from the loft, one within a magnetic anomaly, the other in magnetically quiet terrain, and their tracks were recorded with the help of GPS receivers. A comparison of the beginning of the tracks revealed striking differences: within the anomaly, the initial phase lasted longer, and the distance flown was longer, with the pigeons' headings considerably farther from the home direction. During the following departure phase, the birds were well homeward oriented at the magnetically quiet site, whereas they continued to be disoriented within the anomaly. Comparing the tracks in the anomaly with the underlying magnetic contours shows considerable differences between individuals, without a common pattern emerging. The differences in magnetic intensity along the pigeons' path do not differ from a random distribution of intensity differences around the release site, indicating that the magnetic contours do not directly affect the pigeons' routes. Within the anomaly, pigeons take longer until their flights are oriented, but 5 km from the release point, the birds, still within the anomaly, are also significantly oriented in the home direction. These findings support the assumption that magnetically anomalous conditions initially interfere with the pigeons' navigational processes, with birds showing rather individual responses in their attempts to overcome these problems.     

河源东源:看好“大水缸”,打造“聚宝盆”

正酒香不怕巷子深,没想到头一次搞特色水果直播带货就引发这么多人关注……河源市东源县双江镇父母官笑得合不拢嘴,做好东江源生态链文章,双江必成网红打卡地。言语间,流露出干事创业的自信与激情。万绿湖畔好山好水,千年古道焕发新机,万亩果园硕果累累,美丽乡村游人如织。其实双江镇只是东源县绿水青山就是金山银山发展理念创新实践的一个缩影。     

“搜狐网:“雾霾门诊”挂牌难解公众期待”

正看天决断,对症挂牌,此番雾霾门诊的成立,很显温馨与体贴,自然也能解公众应对雾霾的燃眉之急。但若着眼根本,放眼长远,仅此一个雾霾门诊挂牌,还难解公众健康期待。要想正本清源,还需从多方面入手。雾霾门诊挂牌,不代表公众健康可期待。相反,人们更应通过认识其危害,并在懂得相关知识的基础上,上下齐心,多方用力,打一场     

李海啸:环境监测的“书虫”与“男神”

<正>他留着络腮胡子,带着黑框眼镜,不修边幅的外表下,有着一股科学家钻研创新的精神劲。他叫李海啸,广东省环境监测中心水环境监测与预报预警科的一名技术专家,女同事眼中的技术男神,是全省水环境质量状况分析评价的行家好手。