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Particular Parts (particular + part)
Selected AbstractsHoming in German Cockroaches, Blattella germanica (L.) (Insecta: Dictyoptera): Multi-Channelled Orientation CuesETHOLOGY, Issue 10 2004Colette Rivault Cockroaches use navigational cues to elaborate their return path to the shelter. Our experiments investigated how individuals weighted information to choose where to search for the shelter in situations where path integration, visual and olfactory cues were conflicting. We showed that homing relied on a complex set of environmental stimuli, each playing a particular part. Path integration cues give cockroaches an estimation of the position of their goal, visual landmarks guide them to that position from a distance, while olfactory cues indicate the end of the path. Cockroaches gave the greatest importance to the first cues they encountered along their return path. Nevertheless, visual cues placed beyond aggregation pheromone deposits reduced their arrest efficiency and induced search in the area near the visual cues. [source] Preferences and predispositions of female canaries (Serinus canaria) for loud intensity of male sexy phrasesBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2009MAGALI PASTEAU In the present study, we tested the effect of song amplitude on intersexual relationships. To evaluate preferences and predispositions of female canaries for amplitude levels of male song, we conducted two experiments using both females raised in acoustic isolation and females raised in an aviary under ,normal' acoustic conditions. The songs used in both experiments followed the same pattern: one reactive phrase surrounded by two nonreactive phrases. The first experiment consisted of testing female preferences for weak, normal, or loud amplitudes of the reactive phrase (i.e. these reactive phrases provoke sexual stimulation in females). In a second experiment, we tested female preferences for weak, normal, or loud amplitudes of the nonreactive phrases. These two experiments allowed us to evaluate female preferences for intensity levels of reactive and nonreactive phrases. In the first experiment, all females significantly prefered loud and normal reactive phrases, whereas the second experiment showed that loud nonreactive phrases do not necessarily provoke more responses than other nonreactive phrases. Female canaries were, thus, more stimulated by the intensity level of a particular part of the song. Both females raised in acoustic isolation and in normal acoustic conditions responded in the same way. We can therefore suppose that learning, through acoustic experience, has little influence on preference development for amplitude levels. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 96, 808,814. [source] Using economic instruments to overcome obstacles to in situ conservation of biodiversityINTEGRATIVE ZOOLOGY (ELECTRONIC), Issue 1 2006Jeffrey A. McNEELY Abstract The leading direct cause of the loss of biodiversity is habitat alteration and disruption. If we are to address this cause directly, we need to find ways of changing the behavior of rural people. Experience has shown that this is done most effectively through the use of economic instruments, ranging from taxes that discourage over-exploitation, to direct payments for conservation activities carried out by rural land-owners or those occupying the land. In many parts of the world, governments provide incentives such as tax breaks to private land-owners. Other countries recognize specific use rights on particular parts of the land, enabling the land-owners to earn appropriate benefits. Since many protected areas have resident human populations, it is especially important that they be encouraged to contribute to the objectives of the protected area, and economic incentives offer an important way of doing so; they might, for example, be given employment in the protected area or in associated tourism activities. Direct payments to farmers for conserving watersheds is becoming increasingly popular, in both developed and developing countries. Improved conservation will require both removing perverse subsidies and developing a wide range of approaches for rewarding land-owners for biodiversity conservation activities. [source] A mesh patching method for finite volume modelling of shallow water flowINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 12 2006Keming Hu Abstract A new mesh-patching model is presented for shallow water flow described by the 2D non-linear shallow water (NLSW) equations. The mesh-patching model is based on AMAZON, a high-resolution NLSW engine with an improved HLLC approximate Riemann solver. A new patching algorithm has been developed, which not only provides improved spatial resolution of flow features in particular parts of the mesh, but also simplifies and speeds up the (structured) grid generation process for an area with complicated geometry. The new patching technique is also compatible with increasingly popular parallel computing and adaptive grid techniques. The patching algorithm has been tested with moving bores, and results of test problems are presented and compared to previous work. Copyright © 2005 John Wiley & Sons, Ltd. [source] Life table response experiment analysis of the stochastic growth rateJOURNAL OF ECOLOGY, Issue 2 2010Hal Caswell Summary 1.,Life table response experiment (LTRE) analyses decompose treatment effects on a dependent variable (usually, but not necessarily, population growth rate) into contributions from differences in the parameters that determine that variable. 2.,Fixed, random and regression LTRE designs have been applied to plant populations in many contexts. These designs all make use of the derivative of the dependent variable with respect to the parameters, and describe differences as sums of linear approximations. 3.,Here, I extend LTRE methods to analyse treatment effects on the stochastic growth rate log ,s. The problem is challenging because a stochastic model contains two layers of dynamics: the stochastic dynamics of the environment and the response of the vital rates to the state of the environment. I consider the widely used case where the environment is described by a Markov chain. 4.,As the parameters describing the environmental Markov chain do not appear explicitly in the calculation of log ,s, derivatives cannot be calculated. The solution presented here combines derivatives for the vital rates with an alternative (and older) approach, due to Kitagawa and Keyfitz, that calculates contributions in a way analogous to the calculation of main effects in statistical models. 5.,The resulting LTRE analysis decomposes log ,s into contributions from differences in: (i) the stationary distribution of environmental states, (ii) the autocorrelation pattern of the environment, and (iii) the stage-specific vital rate responses within each environmental state. 6.,As an example, the methods are applied to a stage-classified model of the prairie plant Lomatium bradshawii in a stochastic fire environment. 7.,Synthesis. The stochastic growth rate is an important parameter describing the effects of environmental fluctuations on population viability. Like any growth rate, it responds to differences in environmental factors. Without a decomposition analysis there is no way to attribute differences in the stochastic growth rate to particular parts of the life cycle or particular aspects of the stochastic environment. The methods presented here provide such an analysis, extending the LTRE analyses already available for deterministic environments. [source] Investigation of particular surgical steps in epiretinal prostheses implantation procedure in pigsACTA OPHTHALMOLOGICA, Issue 2009D IVASTINOVIC Purpose Proliferative vitreoretinopathy (PVR) is known a known complication of implantation of epiretinal prostheses in porcine eyes using our combined surgical procedure of vitrectomy, lensectomy, large scleral incision and retinal tack insertion. The aim of the present experimental study is to investigate the intraocular reaction to particular parts of the epiretinal prostheses implantation procedure in pigs. Methods 15 pigs were divided into 3 groups. Group 1 (n=6) underwent vitrectomy, lensectomy, insertion of inactive epiretinal prosthesis through a scleral incision and fixation to the posterior pole with a retinal tack. In group 2 (n=5) vitrectomy, scleral incision and retinal tack insertion were performed. Group 3 (n=4) received vitrectomy, scleral incision and insertion of a shortened prosthesis into the vitreous cavity. The follow up was 4 weeks. Results PVR was observed in all eyes of group 1 and in one eye of the group 3 with unintentional perforation of the lens capsule by the shortened implant. In all other eyes funduscopy revealed no clinical pathology. Conclusion Our results indicate that lensectomy is the key stimulus for PVR in porcine eyes while other steps of the implantation procedure are well tolerated. Though pigs do not seem to be a reactive animal model, lens manipulation should be avoided in the surgical procedure for the implantation of retinal prostheses. [source] | ||||||||||