614 research outputs found

    Possible Use of Wading Birds as Beaters by Snail Kites, Boat-Tailed Grackles, and Limpkins

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    Foraging in single- or mixed-species flocks is common among many bird species, and the advantages of being in these flocks have been the focus of several investigations (reviewed by Moynihan 1962, Bertram 1978). It has been hypothesized that birds occurring in mixed-species flocks gain advantages from (1) reduced predation risk (e.g., Moynihan 1962, Morse 1970), (2) increased foraging efficiency (e.g., Moynihan 1962, Morse 1970), or (3) social learning (e.g., Ward and Zahavi 1973). Here, we report the anomalous occurrence of flocks consisting of species not typically found in the types of aggregations we describe and suggest the possible function of these aggregations with respect to these hypotheses

    Intranasal Inhalation of Oxytocin Improves Face Processing in Developmental Prosopagnosia

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    Developmental prosopagnosia (DP) is characterised by a severe, lifelong impairment in face recognition. Little work has attempted to improve face processing in these individuals, but intriguingly, recent evidence suggests oxytocin can improve face processing in both healthy participants and individuals with autism. This study examined whether oxytocin could also improve face processing in individuals with DP. Ten adults with the condition and 10 matched controls were tested using a randomized placebo-controlled double-blind within-subject experimental design (AB-BA). Each participant took part in two testing sessions where they inhaled 24IU of oxytocin or placebo spray and completed two face processing tests: one assessing face memory and the other face perception. Results showed main effects of both participant group and treatment condition in both face processing tests, but the two did not interact. Specifically, the performance of DP participants was significantly lower than control performance under both oxytocin and placebo conditions, but oxytocin improved processing to a similar extent in both groups

    Characterising developmental prosopagnosia: What can subtypes tell us?

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    Developmental prosopagnosia (DP) is a heterogeneous condition. Some people fail to recognise faces due to problems with face perception (apperceptive subtype), whereas others show normal perception, but poor memory for faces (associative subtype). Furthermore, some (but not all) DPs report difficulties with other cognitive tasks, such as judging emotional expressions, navigation, and within-class object recognition. This study examined whether different subtypes of DP present with different cognitive profiles. We recruited a large group of DPs (N = 36) and control participants, and examined their performance on a range of cognitive and face-processing tasks. The DP group was split into subtypes using the Cambridge Face Perception Test (Duchaine, Germine, & Nakayama, 2007). Overall, differences between subtypes were minimal: both reported similar rates of problems with navigation and within-class object discrimination; both showed smaller inversion effects for faces than controls; neither showed a composite effect for faces; and neither showed impairments when asked to discriminate facial expression, age, and gender. However, the groups diverged when discriminating changes in facial features, spacing, and contours. Overall, our results suggest that different subtypes of DP may manifest in subtle ways. We will discuss how these differences may inform future research and training programmes for DPs

    11 W narrow linewidth laser source at 780nm for laser cooling and manipulation of Rubidium

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    We present a narrow linewidth continuous laser source with over 11 Watts of output power at 780nm, based on single-pass frequency doubling of an amplified 1560nm fibre laser with 36% efficiency. This source offers a combination of high power, simplicity, mode quality and stability. Without any active stabilization, the linewidth is measured to be below 10kHz. The fibre seed is tunable over 60GHz, which allows access to the D2 transitions in 87Rb and 85Rb, providing a viable high-power source for laser cooling as well as for large-momentum-transfer beamsplitters in atom interferometry. Sources of this type will pave the way for a new generation of high flux, high duty-cycle degenerate quantum gas experiments.Comment: 5 pages, 3 figure

    Adaptation of Australian houses and households to future heat waves

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    Climate change predictions indicate more extremes in weather conditions in the coming decades with more frequent and severe heat waves in certain locations including Australia. It is likely that the more vulnerable members of the community will be at risk during heat waves in the future from both health and financial perspectives. The trend towards fully air conditioned larger homes has already seen very large peaks in electricity demand during past heat waves with associated system failures. The impact of increased periods of hot weather, electricity price rises and system failure can be addressed in part through household behaviour; however it is concurrently exacerbated by housing designs which limit occupant choice. This paper employs outputs from the thermal analysis of typical Australian housing types to discuss this relationship between behaviour and design in future heat wave scenarios. Particular attention is given to populated regions forecast to experience a significant increase in heat waves in the future. Alterations to existing buildings and modifications of typical new house designs are utilised to demonstrate methods of reducing risks associated with extended periods of hot weather. In conclusion, a summary of the positive environmental and comfort implications of the modified designs is presented.Jasmine Palmer, Helen Bennetts, Stephen Pullen, Jian Zuo, Tony Ma, Nicholas Chilesh

    Optically guided linear Mach Zehnder atom interferometer

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    We demonstrate a horizontal, linearly guided Mach Zehnder atom interferometer in an optical waveguide. Intended as a proof-of-principle experiment, the interferometer utilises a Bose-Einstein condensate in the magnetically insensitive |F=1,mF=0> state of Rubidium-87 as an acceleration sensitive test mass. We achieve a modest sensitivity to acceleration of da = 7x10^-4 m/s^2. Our fringe visibility is as high as 38% in this optically guided atom interferometer. We observe a time-of-flight in the waveguide of over half a second, demonstrating the utility of our optical guide for future sensors.Comment: 6 pages, 3 figures. Submitted to Phys. Rev.

    The Proportion of Snail Kites Attempting to Breed and the Number of Breeding Attempts per Year in Florida

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    During the breeding season of 1995 we monitored the proportion of adult and subadult Snail Kites (Rostrhamus sociabilis) attempting to breed and the number of breeding attempts using radio telemetry. Our sample consisted of 23 adults (14 females, 9 males) and 9 subadults for which we had data over the entire breeding season. All adults attempted to breed at least once with an observed average of 1.4 (± 0.6 SD) breeding attempts per individual. In contrast, only 3 (33%) of the subadults attempted to breed. Of the adults, 15 (65%) made one breeding attempt, 7 (30%) made two breeding attempts,and 1 (4%) attempted three times. Only one bird (4%) successfully raised two broods. Our data are consistent with previous reports that \u3e1 breeding attempt by Snail Kites in Florida is common during some years, although our estimate for 1995 was lower han previously reported estimates. A combination of our estimation procedures, definitions of a breeding attempt, and annual variability of this parameter probably account for the disparity between our data and previous reports
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