A new argument against cooling by convective air eddies formed above sunlit zebra stripes

There is a long-lasting debate about the possible functions of zebra stripes. According to one hypothesis, periodical convective air eddies form over sunlit zebra stripes which cool the body. However, the formation of such eddies has not been experimentally studied. Using schlieren imaging in the laboratory, we found: downwelling air streams do not form above the white stripes of light-heated smooth or hairy striped surfaces. The influence of stripes on the air stream formation (facilitating upwelling streams and hindering horizontal stream drift) is negligible higher than 1-2 cm above the surface. In calm weather, upwelling air streams might form above sunlit zebra stripes, however they are blown off by the weakest wind, or even by the slowest movement of the zebra. These results forcefully contradict the thermoregulation hypothesis involving air eddies

Lamp-Lit Bridges as Dual Light-Traps for the Night-Swarming Mayfly, <i>Ephoron virgo</i>: Interaction of Polarized and Unpolarized Light Pollution

<div><p>Ecological photopollution created by artificial night lighting can alter animal behavior and lead to population declines and biodiversity loss. Polarized light pollution is a second type of photopollution that triggers water-seeking insects to ovisposit on smooth and dark man-made objects, because they simulate the polarization signatures of natural water bodies. We document a case study of the interaction of these two forms of photopollution by conducting observations and experiments near a lamp-lit bridge over the river Danube that attracts mass swarms of the mayfly <i>Ephoron virgo</i> away from the river to oviposit on the asphalt road of the bridge. Millions of mayflies swarmed near bridge-lights for two weeks. We found these swarms to be composed of 99% adult females performing their upstream compensatory flight and were attracted upward toward unpolarized bridge-lamp light, and away from the horizontally polarized light trail of the river. Imaging polarimetry confirmed that the asphalt surface of the bridge was strongly and horizontally polarized, providing a supernormal ovipositional cue to <i>Ephoron virgo</i>, while other parts of the bridge were poor polarizers of lamplight. Collectively, we confirm that <i>Ephoron virgo</i> is independently attracted to both unpolarized and polarized light sources, that both types of photopollution are being produced at the bridge, and that spatial patterns of swarming and oviposition are consistent with evolved behaviors being triggered maladaptively by these two types of light pollution. We suggest solutions to bridge and lighting design that should prevent or mitigate the impacts of such scenarios in the future. The detrimental impacts of such scenarios may extend beyond <i>Ephoron virgo</i>.</p></div

Nocturnal artificial sources of unpolarized and horizontally polarized light interact to attract polarotactic insects.

<p>Unpolarlized light sources (e.g., street-lamps) may attract perching or flying nocturnal polarotactic insects directly (<i>Ephoron virgo</i> mayfly illustrated). Alternatively, unpolarized light from the street-lamp can become horizontally polarized through reflection from smooth, dark surfaces like asphalt, simulating the appearance of a water body.</p

(A, B) Color photograph, patterns of the degree <i>d</i> and angle α (clockwise from the vertical) of linear polarization, and areas detected polarotactically as water (for which <i>d</i> > 15% and 80° < α < 100°) of the dry asphalt road on the bridge (above the river Danube at Tahitótfalu) illuminated by bridge-lamps at night during the mass congregation of <i>Ephoron virgo</i> mayflies.

<p>The patterns were measured by imaging polarimetry in the blue (450 nm) part of the spectrum from two different directions of view, when the optical axis of the polarimeter pointed toward North (A) and West (B). The angle of elevation of the optical axis of the polarimeter was 20° from the horizontal. In the α-pattern the local direction of polarization of asphalt-reflected light is shown by a double-headed arrow. The white spot composed of millions of <i>Ephoron virgo</i> carcasses on the asphalt road below the bridge-lamp is well visible on the photographs as well as in the patterns of the degree of polarization <i>d</i> and the area detected as water.</p

Estimated numbers of <i>Ephoron virgo</i> mayflies attracted to polarized and unpolarized light sources placed above the Danube river on four dates in 2012.

<p>Number (mean ± standard deviation) of mayflies attracted to horizontally polarized (continuous line) and unpolarized (dashed line) light as a function of time (= local summer time = GMT + 2 hours, where GMT = Greenwich Mean Time). Each estimate is based on 10 photographs (see subsection <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0121194#sec015" target="_blank">Experiments with linear polarizers</a> of the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0121194#sec011" target="_blank">Materials and Methods</a>). Comparisons of total detections over the course of each test indicate that more individuals were attracted to polarized versus unpolarized light sources of the same intensity: (A) 23 August, N = 11582, U = 181, Z = 10.302, p < 0.00001; (B) 24 August, N = 22786, U = 674.5, Z = 11.388, p < 0.00001; (C) 27 August, N = 5425, U = 303.5, Z = 8.945, p < 0.00001; (D) 28 August, N = 93935, U = 8682, Z = 10.465, p < 0.00001, where N is the number of total mayfly detections, U is the parameter giving the sum of ranks used in the non-parametric method, Z is the standard deviation of data for a given p, and p is the level of significancy (p < 0.05 means significant).</p

As Fig. 3 for the same asphalt road illuminated by light from the clear sky after sunset and measured from two different directions of view, when the optical axis of the polarimeter pointed toward South (A) and East (B).

<p>(C) As A and B for the down-stream side of the bridge and the Danube river.</p

The impact of the Internet on professional relationships: the case of health care

This paper considers the impact of the internet on professional services, specifically healthcare services which have been characterised as asymmetrical in information and power distribution. For complex professional services the internet is primarily an information resource offering perceived parity with professionals. Based on interviews with healthcare professionals and website managers, this paper considers how professionals perceive the internet to be changing patterns of professional-consumer interaction and the nature of professional-consumer relationships. Manifest at service encounter level and health policy level, professionals perceived the evolving parameters of the consumer role to be generating a requirement for a fundamental revision of models of service delivery and professional roles