2,620 research outputs found
Using Age and Spatial Flow Structures in the Indirect Estimation of Migration Streams
No full textThis paper presents a modeling strategy for describing and estimating interregional migration flows. The categorical log-linear model is used to demonstrate various approaches to estimation, including direct and indirect methods. And estimates of known data on interdivisional migration patterns in the United States during the 1995-2000 period are used to illustrate the effectiveness of the various log-linear models. The important aspects of the modeling strategy presented in this paper include parameter interpretation, incorporation of auxiliary or a priori information, and assessment of the various model predictions. The results show that capturing the interactions between origins and destinations are very important for accurate predictions
Effects of light stimulation in embryo on the use of position-specific and object-specific cues in binocular and monocular chicks.
No full textEffects of light stimulation of embryos on the use of position-specific and object-specific cues in binocular and monocular domestic chicks (Gallus gallus)
No full textEffects of light stimulation of embryos on the use of position-specific and object-specific cues in binocular and monocular domestic chicks (Gallus gallus) (vol 163, pg 10, 2005)
No full textERRATA OF "CHIANDETTI ET AL., 2005
Cortisol levels in hair reflect behavioural reactivity of dogs to acoustic stimuli
No full textCortisol levels in hair samples were examined in fourteen domestic dogs and related to the dogs' responses to different acoustic stimuli. Stimuli were playbacks of species-typical vocalizations recorded during three different situations ("disturbance", "isolation" and "play" barks) and the sounds of a thunderstorm. Hair samples were collected at 9:00h and 17:00h two weeks after the behavioural tests. Results showed that behavioural reactivity to playback of the various stimuli correlates with cortisol levels in hair samples collected at 9:00h, and the same was the case for the separate measures of behaviour (i.e. hiding, running away, seeking attention from the tester, panting and lowering of the body posture). Hence, levels of cortisol in hair appear to reflect the dog's chronic state of emotional reactivity, or temperament
Hemispheric specialization in dogs for processing different acoustic stimuli
No full textConsiderable experimental evidence shows that functional cerebral asymmetries are widespread in animals. Activity of the right cerebral hemisphere has been associated with responses to novel stimuli and the expression of intense emotions, such as aggression, escape behaviour and fear. The left hemisphere uses learned patterns and responds to familiar stimuli. Although such lateralization has been studied mainly for visual responses, there is evidence in primates that auditory perception is lateralized and that vocal communication depends on differential processing by the hemispheres. The aim of the present work was to investigate whether dogs use different hemispheres to process different acoustic stimuli by presenting them with playbacks of a thunderstorm and their species-typical vocalizations. The results revealed that dogs usually process their species-typical vocalizations using the left hemisphere and the thunderstorm sounds using the right hemisphere. Nevertheless, conspecific vocalizations are not always processed by the left hemisphere, since the right hemisphere is used for processing vocalizations when they elicit intense emotion, including fear. These findings suggest that the specialisation of the left hemisphere for intraspecific communication is more ancient that previously thought, and so is specialisation of the right hemisphere for intense emotions
Chicks prefer to peck at insect-like elongated stimuli moving in a direction orthogonal to their longer axis
No full textSpontaneous preferences towards possible prey have been little investigated using targets in motion. Preferences of domestic chicks ('Gallus gallus') to peck at video-images of stimuli representing live insects moving along their longer body axis (i.e. "forwards") or along the shorter body axis (i.e. "sideways") were investigated. Chicks presented with both types of stimulus displayed a significant preference for pecking at stimuli moving sideways. This preference was already present on day 1 post-hatching, and it strengthened on day 6 for those chicks that had experienced pecking at live insects. Head angles used to fixate the stimuli prior to pecking were also analysed and were consistent (i.e. 30°–35° and 60°–65°) with those reported for fixation of non-edible targets (larger stimuli at a distance). In a first control experiment the same video-presented stimuli were used but the insect's legs were removed to reduce flickering. In a second control experiment, paper-printed images of the whole insect were used. In both cases, the sideways direction of movement was clearly preferred. Overall, our data show that chicks have a spontaneous preference to peck at video-images resembling live insects moving along their shorter body axis. Sideways movement may constitute a crucial signal attracting chicks' attention and enhancing predatory responses possibly because of stronger stimulation of motion detectors
Incremental sensitivities when Xpert MTB/RIF and LJ are used selectively in the HIV positive population.
No full textStrategy: 1- Fronting Microscopy, 2- Fronting Xpert MTB/RIF, 3- Microscopy followed by Xpert MTB/RIF, 4- Xpert MTB/RIF followed by LJ Culture, 5- Microscopy, followed by Xpert MTB/RIF followed by LJ.</p
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