740 research outputs found
A comparative study of two agamid lizards, Laudakia stellio and Pseudotrapelus sinaitus, in southern Sinai
The study compared habitat use and behaviour in two sympatric species of agamid lizard, Laudakia stellio and Pseudotrapelus sinaitus. Despite sharing the same habitat, the two species differed in their utilisation of microhabitats within it. Pseudotrapelus spent significantly longer on rocks compared to Laudakia. Pseudotrapelus showed evidence of heliothermic regulation, spending most of the time in the sun, but moving into the shade in the warmer afternoons. These varying temporal patterns may reflect differential thermoregulatory requirements between the two lizard species. Pseudotrapelus can change colour rapidly. There was no evidence of any thermoregulatory function in this ability; it is likely to be a form of social communication. Being brightly coloured was associated with behaviours implying increased conspicuousness: blue lizards were alert and vigilant for an average of 93% of each viewing session, compared to just 60% of the time in non-blue camouflaged lizards. The striking nature of the transitory blue colouration suggests it may have evolved for maximum salience, a trait common with signals. We simulated social encounters using blue model lizards and mirrors. Behavioural responses to these stimuli all involved colour changes, and support the social-signaling hypothesis
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Quantifying the contributions to stratospheric ozone changes from ozone depleting substances and greenhouse gases
A state-of-the-art chemistry climate model coupled to a three-dimensional ocean model is used to produce three experiments, all seamlessly covering the period 1950ā2100, forced by different combinations of long-lived Greenhouse Gases (GHGs) and Ozone Depleting Substances (ODSs). The experiments are designed to quantify the separate effects of GHGs and ODSs on the evolution of ozone, as well as the extent to which these effects are independent of each other, by alternately holding one set of these two forcings constant in combination with a third experiment where both ODSs and GHGs vary. We estimate that up to the year 2000 the net decrease in the column amount of ozone above 20 hPa is approximately 75% of the decrease that can be attributed to ODSs due to the offsetting effects of cooling by increased CO2. Over the 21st century, as ODSs decrease, continued cooling from CO2 is projected to account for more than 50% of the projected increase in ozone above 20 hPa. Changes in ozone below 20 hPa show a redistribution of ozone from tropical to extra-tropical latitudes with an increase in the Brewer-Dobson circulation. In addition to a latitudinal redistribution of ozone, we find that the globally averaged column amount of ozone below 20 hPa decreases over the 21st century, which significantly mitigates the effect of upper stratospheric cooling on total column ozone. Analysis by linear regression shows that the recovery of ozone from the effects of ODSs generally follows the decline in reactive chlorine and bromine levels, with the exception of the lower polar stratosphere where recovery of ozone in the second half of the 21st century is slower than would be indicated by the decline in reactive chlorine and bromine concentrations. These results also reveal the degree to which GHGrelated effects mute the chemical effects of N2O on ozone in the standard future scenario used for the WMO Ozone Assessment. Increases in the residual circulation of the atmosphere and chemical effects from CO2 cooling more than halve the increase in reactive nitrogen in the mid to upper stratosphere that results from the specified increase in N2O between 1950 and 2100
ŠŠæŃŠµŠ“ŠµŠ»ŠµŠ½ŠøŠµ ŃŠ°ŃŃ Š¾Š“Š½ŃŃ Ń Š°ŃŠ°ŠŗŃŠµŃŠøŃŃŠøŠŗ Š² ŃŠµŃ Š½Š¾Š»Š¾Š³ŠøŃŠµŃŠŗŠøŃ ŠæŃŠ¾ŃŠµŃŃŠ°Ń Ń ŠŗŠ¾Š½ŃŃŠ¾Š»ŠøŃŃŠµŠ¼ŃŠ¼ Š“Š°Š²Š»ŠµŠ½ŠøŠµŠ¼
Assessment of the environmental and economic performance of a safety valve requires information about the flow of the substance through the valve when it is actuated. The goal of this paper was to determine the flow rate of the discharged substance and the mass flow rate of the substance entering the safety valve when it is actuated.Proposed a mathematical model to describe the processes occurring in the valve. The model includes a system of differential equations describing the physical laws of conservation in the internal volume of the valve and differential equations, which link the value of gas flow through the valve with the pressure and the amount of movement of the shut-off disk. Used a modified method by S.K. Godunov to solve gasdynamic equations.Established that the determination of the flow and power characteristics of the valve requires the preliminary construction of a mathematical model of the safety valve operation. Based on this, proposed a method for determining the flow rate of the discharged substance and the mass rate of the substance entering the safety valve when it is actuated.Obtained the flow characteristics of the valves under review and the dynamics of movement of the shutoff disc of the valve, as well as the dependence of the pressure change on the opening time of the valve. Comparison of the calculated values with available experimental data gives good agreement of results (no more than 5.6 % for a gas flow rate, under 10 % for the movement of the valve and change the arrival of gas in time using the standard deviation function of the flow characteristics of 0.6 %), confirms the correctness of the defined mathematical model, used numerical schemes and algorithms, as well as the proposed method and recoverability of the arrival of gas in a pressureātime curve.ŠŃŠµŠ½ŠŗŠ° ŃŠŗŠ¾Š»Š¾Š³ŠøŃŠ½Š¾ŃŃŠø Šø ŃŠŗŠ¾Š½Š¾Š¼ŠøŃŠ½Š¾ŃŃŠø ŃŠ°Š±Š¾ŃŃ ŠæŃŠµŠ“Š¾Ń
ŃŠ°Š½ŠøŃŠµŠ»ŃŠ½Š¾Š³Š¾ ŠŗŠ»Š°ŠæŠ°Š½Š° ŃŃŠµŠ±ŃŠµŃ ŠøŠ½ŃŠ¾ŃŠ¼Š°ŃŠøŠø Š¾ ŃŠ°ŃŃ
Š¾Š“Šµ Š²ŠµŃŠµŃŃŠ²Š° ŃŠµŃŠµŠ· ŠŗŠ»Š°ŠæŠ°Š½ ŠæŃŠø ŠµŠ³Š¾ ŃŃŠ°Š±Š°ŃŃŠ²Š°Š½ŠøŠø. Š¦ŠµŠ»ŃŃ Š“Š°Š½Š½Š¾Š¹ ŃŠ°Š±Š¾ŃŃ ŃŠ²Š»ŃŠ»Š¾ŃŃ Š¾ŠæŃŠµŠ“ŠµŠ»ŠµŠ½ŠøŠµ Š²ŠµŠ»ŠøŃŠøŠ½Ń ŃŠ°ŃŃ
Š¾Š“Š° ŃŠ±ŃŠ°ŃŃŠ²Š°ŠµŠ¼Š¾Š³Š¾ Š²ŠµŃŠµŃŃŠ²Š° Šø Š¼Š°ŃŃŠ¾Š²Š¾Š¹ ŃŠŗŠ¾ŃŠ¾ŃŃŠø ŠæŠ¾ŃŃŃŠæŠ»ŠµŠ½ŠøŃ Š²ŠµŃŠµŃŃŠ²Š° Š² ŠæŃŠµŠ“Š¾Ń
ŃŠ°Š½ŠøŃŠµŠ»ŃŠ½ŃŠ¹ ŠŗŠ»Š°ŠæŠ°Š½ ŠæŃŠø ŠµŠ³Š¾ ŃŃŠ°Š±Š°ŃŃŠ²Š°Š½ŠøŠø.ŠŠ»Ń Š¾ŠæŠøŃŠ°Š½ŠøŃ ŠæŃŠ¾ŃŠµŃŃŠ¾Š², ŠæŃŠ¾ŃŠµŠŗŠ°ŃŃŠøŃ
Š² ŠŗŠ»Š°ŠæŠ°Š½Šµ, ŠæŃŠµŠ“Š»Š¾Š¶ŠµŠ½Š° Š¼Š°ŃŠµŠ¼Š°ŃŠøŃŠµŃŠŗŠ°Ń Š¼Š¾Š“ŠµŠ»Ń, Š²ŠŗŠ»ŃŃŠ°ŃŃŠ°Ń ŃŠøŃŃŠµŠ¼Ń Š“ŠøŃŃŠµŃŠµŠ½ŃŠøŠ°Š»ŃŠ½ŃŃ
ŃŃŠ°Š²Š½ŠµŠ½ŠøŠ¹, Š¾ŠæŠøŃŃŠ²Š°ŃŃŠøŃ
ŃŠøŠ·ŠøŃŠµŃŠŗŠøŠµ Š·Š°ŠŗŠ¾Š½Ń ŃŠ¾Ń
ŃŠ°Š½ŠµŠ½ŠøŃ Š²Š¾ Š²Š½ŃŃŃŠµŠ½Š½ŠµŠ¼ Š¾Š±ŃŃŠ¼Šµ ŠŗŠ»Š°ŠæŠ°Š½Š° Šø Š“ŠøŃŃŠµŃŠµŠ½ŃŠøŠ°Š»ŃŠ½ŃŠµ ŃŃŠ°Š²Š½ŠµŠ½ŠøŃ, ŃŠ²ŃŠ·ŃŠ²Š°ŃŃŠøŠµ Š²ŠµŠ»ŠøŃŠøŠ½Ń ŃŠ°ŃŃ
Š¾Š“Š° Š³Š°Š·Š° ŃŠµŃŠµŠ· ŠŗŠ»Š°ŠæŠ°Š½ Ń Š“Š°Š²Š»ŠµŠ½ŠøŠµŠ¼ Šø Š²ŠµŠ»ŠøŃŠøŠ½Š¾Š¹ ŠæŠµŃŠµŠ¼ŠµŃŠµŠ½ŠøŃ Š·Š°ŠæŠ¾ŃŠ½Š¾Š³Š¾ Š“ŠøŃŠŗŠ°. ŠŠ»Ń ŃŠµŃŠµŠ½ŠøŃ Š³Š°Š·Š¾Š“ŠøŠ½Š°Š¼ŠøŃŠµŃŠŗŠøŃ
ŃŃŠ°Š²Š½ŠµŠ½ŠøŠ¹ ŠæŃŠøŠ¼ŠµŠ½ŃŠ»ŃŃ Š¼Š¾Š“ŠøŃŠøŃŠøŃŠ¾Š²Š°Š½Š½ŃŠ¹ Š¼ŠµŃŠ¾Š“ Š”.Š. ŠŠ¾Š“ŃŠ½Š¾Š²Š°.Š£ŃŃŠ°Š½Š¾Š²Š»ŠµŠ½Š¾, ŃŃŠ¾ Š¾ŠæŃŠµŠ“ŠµŠ»ŠµŠ½ŠøŠµ ŃŠ°ŃŃ
Š¾Š“Š½Š¾Š¹ Šø ŃŠøŠ»Š¾Š²Š¾Š¹ Ń
Š°ŃŠ°ŠŗŃŠµŃŠøŃŃŠøŠŗ ŠŗŠ»Š°ŠæŠ°Š½Š° ŃŃŠµŠ±ŃŠµŃ ŠæŃŠµŠ“Š²Š°ŃŠøŃŠµŠ»ŃŠ½Š¾Š³Š¾ ŠæŠ¾ŃŃŃŠ¾ŠµŠ½ŠøŃ Š¼Š°ŃŠµŠ¼Š°ŃŠøŃŠµŃŠŗŠ¾Š¹ Š¼Š¾Š“ŠµŠ»Šø ŃŃŠ½ŠŗŃŠøŠ¾Š½ŠøŃŠ¾Š²Š°Š½ŠøŃ ŠæŃŠµŠ“Š¾Ń
ŃŠ°Š½ŠøŃŠµŠ»ŃŠ½Š¾Š³Š¾ ŠŗŠ»Š°ŠæŠ°Š½Š°. ŠŠ° Š¾ŃŠ½Š¾Š²Š°Š½ŠøŠø ŃŠµŠ³Š¾ ŠæŃŠµŠ“Š»Š¾Š¶ŠµŠ½Š° Š¼ŠµŃŠ¾Š“ŠøŠŗŠ° Š¾ŠæŃŠµŠ“ŠµŠ»ŠµŠ½ŠøŃ Š²ŠµŠ»ŠøŃŠøŠ½Ń ŃŠ°ŃŃ
Š¾Š“Š° ŃŠ±ŃŠ°ŃŃŠ²Š°ŠµŠ¼Š¾Š³Š¾ Š²ŠµŃŠµŃŃŠ²Š° Šø Š¼Š°ŃŃŠ¾Š²Š¾Š¹ ŃŠŗŠ¾ŃŠ¾ŃŃŠø ŠæŠ¾ŃŃŃŠæŠ»ŠµŠ½ŠøŃ Š²ŠµŃŠµŃŃŠ²Š° Š² ŠæŃŠµŠ“Š¾Ń
ŃŠ°Š½ŠøŃŠµŠ»ŃŠ½ŃŠ¹ ŠŗŠ»Š°ŠæŠ°Š½ ŠæŃŠø ŠµŠ³Š¾ ŃŃŠ°Š±Š°ŃŃŠ²Š°Š½ŠøŠø.ŠŠ¾Š»ŃŃŠµŠ½Ń ŃŠ°ŃŃ
Š¾Š“Š½ŃŠµ Ń
Š°ŃŠ°ŠŗŃŠµŃŠøŃŃŠøŠŗŠø ŃŠ°ŃŃŠ¼Š°ŃŃŠøŠ²Š°ŠµŠ¼ŃŃ
ŠŗŠ»Š°ŠæŠ°Š½Š¾Š² Šø Š“ŠøŠ½Š°Š¼ŠøŠŗŠ° ŠæŠµŃŠµŠ¼ŠµŃŠµŠ½ŠøŃ Š·Š°ŠæŠ¾ŃŠ½Š¾Š³Š¾ Š“ŠøŃŠŗŠ° ŠŗŠ»Š°ŠæŠ°Š½Š°, Š° ŃŠ°ŠŗŠ¶Šµ Š·Š°Š²ŠøŃŠøŠ¼Š¾ŃŃŃ ŠøŠ·Š¼ŠµŠ½ŠµŠ½ŠøŃ Š“Š°Š²Š»ŠµŠ½ŠøŃ Š¾Ń Š²ŃŠµŠ¼ŠµŠ½Šø Š¾ŃŠŗŃŃŃŠøŃ ŠŗŠ»Š°ŠæŠ°Š½Š°. Š”Š¾ŠæŠ¾ŃŃŠ°Š²Š»ŠµŠ½ŠøŠµ ŃŠ°ŃŃŃŃŠ½ŃŃ
Š·Š½Š°ŃŠµŠ½ŠøŠ¹ Ń ŠøŠ¼ŠµŃŃŠøŠ¼ŠøŃŃ ŃŠŗŃŠæŠµŃŠøŠ¼ŠµŠ½ŃŠ°Š»ŃŠ½ŃŠ¼Šø Š“Š°Š½Š½ŃŠ¼Šø Š“Š°ŃŃ Ń
Š¾ŃŠ¾ŃŠµŠµ ŃŠ¾Š²ŠæŠ°Š“ŠµŠ½ŠøŠµ (Š½Šµ Š±Š¾Š»ŠµŠµ 5,6 % Š“Š»Ń ŃŠ°ŃŃ
Š¾Š“Š° Š³Š°Š·Š°, Š¼ŠµŠ½ŠµŠµ 10 % Š“Š»Ń ŠæŠµŃŠµŠ¼ŠµŃŠµŠ½ŠøŃ ŠŗŠ»Š°ŠæŠ°Š½Š° Šø ŠøŠ·Š¼ŠµŠ½ŠµŠ½ŠøŃ ŠæŃŠøŃ
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Š°ŃŠ°ŠŗŃŠµŃŠøŃŃŠøŠŗ 0,6 %) ŃŠµŠ·ŃŠ»ŃŃŠ°ŃŠ¾Š², ŠæŠ¾Š“ŃŠ²ŠµŃŠ¶Š“Š°ŠµŃ ŠŗŠ¾ŃŃŠµŠŗŃŠ½Š¾ŃŃŃ ŃŃŠ¾ŃŠ¼ŃŠ»ŠøŃŠ¾Š²Š°Š½Š½Š¾Š¹ Š¼Š°ŃŠµŠ¼Š°ŃŠøŃŠµŃŠŗŠ¾Š¹ Š¼Š¾Š“ŠµŠ»Šø, ŠøŃŠæŠ¾Š»ŃŠ·ŃŠµŠ¼ŃŃ
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ŠµŠ¼ Šø Š°Š»Š³Š¾ŃŠøŃŠ¼Š¾Š², ŠæŃŠµŠ“Š»Š¾Š¶ŠµŠ½Š½Š¾Š¹ Š¼ŠµŃŠ¾Š“ŠøŠŗŠø Šø Š²Š¾Š·Š¼Š¾Š¶Š½Š¾ŃŃŃ Š²Š¾ŃŃŃŠ°Š½Š¾Š²Š»ŠµŠ½ŠøŃ ŠæŃŠøŃ
Š¾Š“Š° Š³Š°Š·Š° ŠæŠ¾ ŠŗŃŠøŠ²Š¾Š¹ Š“Š°Š²Š»ŠµŠ½ŠøŠµāāāŠ²ŃŠµŠ¼Ń
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Application of the random encounter model in citizen science projects to monitor animal densities
Abundance and density are vital metrics for assessing a speciesā conservation status and for developing effective management strategies. Remote-sensing cameras are being used increasingly as part of citizen science projects to monitor wildlife, but current methodologies to monitor densities pose challenges when animals are not individually recognisable. We investigate the use of camera traps and the Random Encounter Model (REM) for estimating the density of West European hedgehogs (Erinaceus europaeus) within a citizen science framework. We evaluate the use of a simplified version of the REM in terms of the parametersā estimation (averaged versus survey-specific) and asses itās potential application as part of a large-scale, long-term citizen science project. We compare averaged REM estimates to those obtained via Spatial Capture-Recapture (SCR) using data from nocturnal spotlight surveys. There was a high degree of concordance in REM-derived density estimates from averaged parameters versus those derived from survey-specific parameters. Averaged REM density estimates were also comparable to those produced by SCR at 8 out of 9 sites; hedgehog density was 7.5 times higher in urban (32.3 km-2) versus rural (4.3 km2) sites. Power analyses indicated that the averaged REM approach would be able to detect a 25% change in hedgehog density in both habitats with >90% power. Furthermore, despite the high start-up costs associated with the REM method, it would be cost-effective in the long term. The averaged REM approach is a promising solution to the challenge of large-scale and long-term species monitoring. We suggest including the REM as part of a citizen science monitoring project, where participants collect data and researchers verify and implement the required analysis
Social network analysis shows direct evidence for social transmission of tool use in wild chimpanzees
The authors are grateful to the Royal Zoological Society of Scotland for providing core funding for the Budongo Conservation Field Station. The fieldwork of CH was funded by the Leverhulme Trust, the Lucie Burgers Stichting, and the British Academy. TP was funded by the Canadian Research Chair in Continental Ecosystem Ecology, and received computational support from the Theoretical Ecosystem Ecology group at UQAR. The research leading to these results has received funding from the People Programme (Marie Curie Actions) and from the European Research Council under the European Union's Seventh Framework Programme (FP7/2007ā2013) REA grant agreement nĀ°329197 awarded to TG, ERC grant agreement nĀ° 283871 awarded to KZ. WH was funded by a BBSRC grant (BB/I007997/1).Social network analysis methods have made it possible to test whether novel behaviors in animals spread through individual or social learning. To date, however, social network analysis of wild populations has been limited to static models that cannot precisely reflect the dynamics of learning, for instance, the impact of multiple observations across time. Here, we present a novel dynamic version of network analysis that is capable of capturing temporal aspects of acquisition-that is, how successive observations by an individual influence its acquisition of the novel behavior. We apply this model to studying the spread of two novel tool-use variants, "moss-sponging'' and "leaf-sponge re-use,'' in the Sonso chimpanzee community of Budongo Forest, Uganda. Chimpanzees are widely considered the most "cultural'' of all animal species, with 39 behaviors suspected as socially acquired, most of them in the domain of tool-use. The cultural hypothesis is supported by experimental data from captive chimpanzees and a range of observational data. However, for wild groups, there is still no direct experimental evidence for social learning, nor has there been any direct observation of social diffusion of behavioral innovations. Here, we tested both a static and a dynamic network model and found strong evidence that diffusion patterns of moss-sponging, but not leaf-sponge re-use, were significantly better explained by social than individual learning. The most conservative estimate of social transmission accounted for 85% of observed events, with an estimated 15-fold increase in learning rate for each time a novice observed an informed individual moss-sponging. We conclude that group-specific behavioral variants in wild chimpanzees can be socially learned, adding to the evidence that this prerequisite for culture originated in a common ancestor of great apes and humans, long before the advent of modern humans.Publisher PDFPeer reviewe
Which executive functioning deficits are associated with AD/HD, ODD/CD and comorbid AD/HD+ODD/CD?
Item does not contain fulltextThis study investigated (1) whether attention deficit/hyperactivity disorder (AD/HD) is associated with executive functioning (EF) deficits while controlling for oppositional defiant disorder/conduct disorder (ODD/CD), (2) whether ODD/CD is associated with EF deficits while controlling for AD/HD, and (3)~whether a combination of AD/HD and ODD/CD is associated with EF deficits (and the possibility that there is no association between EF deficits and AD/HD or ODD/CD in isolation). Subjects were 99~children ages 6ā12 years. Three putative domains of EF were investigated using well-validated tests: verbal fluency, working memory, and planning. Independent of ODD/CD, AD/HD was associated with deficits in planning and working memory, but not in verbal fluency. Only teacher rated AD/HD, but not parent rated AD/HD, significantly contributed to the prediction of EF task performance. No EF deficits were associated with ODD/CD. The presence of comorbid AD/HD accounts for the EF deficits in children with comorbid AD/HD+ODD/CD. These results suggest that EF deficits are unique to AD/HD and support the model proposed by R. A. Barkley (1997).17 p
K-shell photoionization of ground-state Li-like carbon ions [C]: experiment, theory and comparison with time-reversed photorecombination
Absolute cross sections for the K-shell photoionization of ground-state
Li-like carbon [C(1s2s S)] ions were measured by employing the
ion-photon merged-beams technique at the Advanced Light Source. The energy
ranges 299.8--300.15 eV, 303.29--303.58 eV and 335.61--337.57 eV of the
[1s(2s2p)P]P, [1s(2s2p)P]P and [(1s2s)S 3p]P
resonances, respectively, were investigated using resolving powers of up to
6000. The autoionization linewidth of the [1s(2s2p)P]P resonance was
measured to be meV and compares favourably with a theoretical result
of 26 meV obtained from the intermediate coupling R-Matrix method. The present
photoionization cross section results are compared with the outcome from
photorecombination measurements by employing the principle of detailed balance.Comment: 3 figures and 2 table
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