4,888 research outputs found

    Adaptive colour change and background choice behaviour in peppered moth caterpillars is mediated by extraocular photoreception

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    Light sensing by tissues distinct from the eye occurs in diverse animal groups, enabling circadian control and phototactic behaviour. Extraocular photoreceptors may also facilitate rapid colour change in cephalopods and lizards, but little is known about the sensory system that mediates slow colour change in arthropods. We previously reported that slow colour change in twig-mimicking caterpillars of the peppered moth (Biston betularia) is a response to achromatic and chromatic visual cues. Here we show that the perception of these cues, and the resulting phenotypic responses, does not require ocular vision. Caterpillars with completely obscured ocelli remained capable of enhancing their crypsis by changing colour and choosing to rest on colour-matching twigs. A suite of visual genes, expressed across the larval integument, likely plays a key role in the mechanism. To our knowledge, this is the first evidence that extraocular colour sensing can mediate pigment-based colour change and behaviour in an arthropod

    Ethical Leadership in Organisations: A Synthesis of Literature

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    A lot of controversies have arisen in recent times, as corporate leaders are brought under scrutiny by the media and other stakeholders. This has changed the game for a lot of them and it is no longer business as usual. What would have been ignored in times past would make headlines especially when it comes to ethical issues. As a leader of an organization, one is no longer responsible to just the shareholders in terms of maximizing profit. But as ethical leadership is concerned, the responsibility of ensuring that there is a clear line between what is acceptable and what is not acceptable while driving the organization to reaching set goals becomes paramount. The pitfall for several leaders is that, in the bid to achieve short-term goals, they cross the ethical lines which has major repercussions for the entire organization. This paper takes a holistic review of literature at the concepts of ethics, leadership and ethical leadership and the fundamental principles of ethical leadership. It also discusses cases of ethical misappropriations by selected organizations and the consequences of such actions. This conceptual paper provides practical solutions to the issues bordering on ethics and leadership in organisations

    Effects of Excessive Natural Mulch on Development, Yield, and Structure of Native Grassland

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    Prairie vegetation is so universally mowed, grazed, or burned that little information has been recorded on its behavior under complete protection. Climax grassland, when grazed lightly or even moderately, may retain essentially its natural composition over extremely long periods (16, 18). But aside from observation there is little information upon the unusual and rare phenomenon of complete protection of grassland from disturbance over a considerable period of time

    Experimental hut evaluation of bednets treated with an organophosphate (chlorpyrifos-methyl) or a pyrethroid (lambdacyhalothrin) alone and in combination against insecticide-resistant Anopheles gambiae and Culex quinquefasciatus mosquitoes

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    BACKGROUND: Pyrethroid resistant mosquitoes are becoming increasingly common in parts of Africa. It is important to identify alternative insecticides which, if necessary, could be used to replace or supplement the pyrethroids for use on treated nets. Certain compounds of an earlier generation of insecticides, the organophosphates may have potential as net treatments. METHODS: Comparative studies of chlorpyrifos-methyl (CM), an organophosphate with low mammalian toxicity, and lambdacyhalothrin (L), a pyrethroid, were conducted in experimental huts in CĂ´te d'Ivoire, West Africa. Anopheles gambiae and Culex quinquefasciatus mosquitoes from the area are resistant to pyrethroids and organophosphates (kdr and insensitive acetylcholinesterase Ace.1(R)). Several treatments and application rates on intact or holed nets were evaluated, including single treatments, mixtures, and differential wall/ceiling treatments. RESULTS AND CONCLUSION: All of the treatments were effective in reducing blood feeding from sleepers under the nets and in killing both species of mosquito, despite the presence of the kdr and Ace.1(R )genes at high frequency. In most cases, the effects of the various treatments did not differ significantly. Five washes of the nets in soap solution did not reduce the impact of the insecticides on A. gambiae mortality, but did lead to an increase in blood feeding. The three combinations performed no differently from the single insecticide treatments, but the low dose mixture performed encouragingly well indicating that such combinations might be used for controlling insecticide resistant mosquitoes. Mortality of mosquitoes that carried both Ace.1(R )and Ace.1(S )genes did not differ significantly from mosquitoes that carried only Ace.1(S )genes on any of the treated nets, indicating that the Ace.1(R )allele does not confer effective resistance to chlorpyrifos-methyl under the realistic conditions of an experimental hut

    A framework for exploring gender equality outcomes from WASH programmes

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    This paper aims to assist practitioners and researchers in planning, identifying, and documenting gender outcomes associated with water, sanitation, and hygiene (WASH) programmes by proposing a conceptual framework for classifying gender equality changes. Gender outcomes that have been attributed to WASH initiatives encompass those directly related to improved services as well as outcomes that move into areas of relationships, power, and status. There is a growing body of literature identifying WASH-related gender outcomes; however the types of outcomes described vary considerably and further work is needed to inform a comprehensive picture of WASH and gender links. The framework proposed in this paper is based on a synthesis of outcomes reported in WASH literature to date, empirical research in Fiji and Vanuatu, and insights from gender and development literature. It is hoped that the framework will support practitioners to engage with the inherent complexity of gender inquiry, contributing to sector knowledge about the potential for WASH initiatives to advance gender equality. © Practical Action Publishing, 2013

    The CLARIN Knowledge Centre for Atypical Communication Expertise

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    In this chapter we introduce the CLARIN Knowledge Centre for Atypical Communication Expertise. The mission of ACE is to support researchers engaged in languages which pose particular challenges for analysis; for this, we use the umbrella term “atypical communication”. This includes language use by second-language learners, people with language disorders or those suffering from lan-guage disabilities, and languages that pose unique challenges for analysis, such as sign languages and languages spoken in a multilingual context. The chapter presents details about the collaborations and outreach of the centre, the services offered, and a number of showcases for its activities

    Initial Results of DC Electric Fields, Associated Plasma Drifts, Magnetic Fields, and Plasma Waves Observed on the C/NOFS Satellite

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    Initial results are presented from the Vector Electric Field Investigation (VEFI) on the Air Force Communication/Navigation Outage Forecasting System (C/NOFS) satellite, a mission designed to understand, model, and forecast the presence of equatorial ionospheric irregularities. The VEFI instrument includes a vector DC electric field detector, a fixed-bias Langmuir probe operating in the ion saturation regime, a flux gate magnetometer, an optical lightning detector, and associated electronics including a burst memory. Compared to data obtained during more active solar conditions, the ambient DC electric fields and their associated E x B drifts are variable and somewhat weak, typically < 1 mV/m. Although average drift directions show similarities to those previously reported, eastward/outward during day and westward/downward at night, this pattern varies significantly with longitude and is not always present. Daytime vertical drifts near the magnetic equator are largest after sunrise, with smaller average velocities after noon. Little or no pre-reversal enhancement in the vertical drift near sunset is observed, attributable to the solar minimum conditions creating a much reduced neutral dynamo at the satellite altitude. The nighttime ionosphere is characterized by larger amplitude, structured electric fields, even where the plasma density appears nearly quiescent. Data from successive orbits reveal that the vertical drifts and plasma density are both clearly organized with longitude. The spread-F density depletions and corresponding electric fields that have been detected thus far have displayed a preponderance to appear between midnight and dawn. Associated with the narrow plasma depletions that are detected are broad spectra of electric field and plasma density irregularities for which a full vector set of measurements is available for detailed study. Finally, the data set includes a wide range of ELF/VLF/HF oscillations corresponding to a variety of plasma waves, in particular banded ELF hiss, whistlers, and lower hybrid wave turbulence triggered by lightning-induced sferics. The VEFI data represents a new set of measurements that are germane to numerous fundamental aspects of the electrodynamics and irregularities inherent to the Earth's low latitude ionosphere

    A fourth account of centipede (Chilopoda) predation on bats

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    With an incident in Palo Duro Canyon, Texas, USA, Scolopendra heros Girard (Chilopoda: Scolopendromorpha: Scolopendridae) becomes the third centipede species known to prey on bats; S. gigantea Linnaeus and S. viridicornis Newport have been so documented in Venezuela and Brazil, respectively. The Texas predation was interrupted by the predator/prey pair’s falling around 15–20 m from the canyon wall and, perhaps also, by human presence where they landed. The centipede uncoiled and retreated to shelter under a nearby rock and, after initial immobilization, so did the bat. Con un incidente en Palo Duro Canyon, Texas, Estados Unidos, Scolopendra heros Girard (Chilopoda: Scolopendromorpha: Scolopendridae) se convierte en el tercer ciempiés que se sabe depreda murciélagos; S. gigantea Linnaeus y S. viridicornis Newport han sido documentados mostrando este comportamiento en Venezuela y Brasil, respectivamente. El incidente de Texas fue interrumpido por el despeñamiento del par depredador/presa unos 15–20 m desde la pared del cañón y, al parecer, por la presencia humana en el sitio de caída. El ciempiés se desenrolló y retiró para refugiarse bajo una roca cercana. Tras permanecer inmóvil inicialmente, el murciélago hizo lo mismo
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