Acoustic behaviour of southern right whales in relation to numbers of whales present in Walker Bay, South Africa

Estimating numbers of whales present in an area from recorded call rates could be a useful conservation tool. We recorded southern right whale Eubalaena australis vocalisations and presence in Walker Bay on the south coast of South Africa. In all, 45 sessions with synchronous acoustic and visual data were analysed to determine call rates directly (overall call rate, OCR) and in relation to the number of whales sighted (call rate per whale, CPW) and number of groups sighted (call rate per group, CPG). The OCRs were examined in the presence of varying numbers of whales, using a log-linear model to investigate the dependence of the call rate on whale density. The number of whales present exerted a strong quadratic effect on the OCR, which peaked at around 15 whales and decreased to a low rate as whale presence approached a maximum, for all calls combined and for four of their constituent 13 call types: a quadratic trend was present to varying degrees among the remaining call types. Both quadratic and linear trends were absent when OCR was assessed against number of groups present, possibly because group size increased with increasing density of whales. A linear regression on the CPW and CPG suggested that there was a negative inverse relationship with the number of whales and groups present respectively. These findings are important in that, while they preclude the estimation of absolute numbers from call rates, they imply that, under the conditions prevailing in Walker Bay, southern right whales were aware of the presence, arrival and departure of other animals in their vicinity and adjusted their vocal behaviour accordingly.The National Research Foundation, the Worldwide Fund for Nature, South Africa (WWF SA), PetroSA (formerly Soekor), the Wildlife and Environment Society of South Africa and Spescom,.http://www.tandfonline.com/loi/tams20nf201

Fire Responses in Four Rare Plant Species at Gibraltar Range National Park, Northern Tablelands, NSW

Fire responses are reported in four rare species at Gibraltar Range National Park following hazard reduction burning. 'Acacia barringtonensis' Tindale, 'Grevillea rhizomatosa' P.M. Olde & N.R. Marriot, Persoonia rufa L.A.S. Johnson & P. H. Weston and 'Telopea aspera' M.D. Crisp & P.H. Weston were the species investigated. In each species, individuals were tagged prior to a hazard reduction fire and their fates followed for 34 months. In 'Acacia barringtonensis', individuals survived fire and resprouted from buds at the base of stems and from rhizomes but the resprouts were heavily browsed by insects and Swamp Wallabies ('Wallabia bicolor' Desmarest). In 'Grevillea rhizomatosa', individuals survived and resprouted from underground rhizomes and no seedlings were found after fires. After fire in Persoonia rufa, all scorched plants died but seedling recruitment occurred from a soil-stored seed. In 'Telopea aspera', most burnt individuals resprouted from basal shoots and survived despite heavy post-fire grazing pressure. Increasing fire frequencies by hazard-reduction burning may threaten the survival of all four species, and it is suggested that other methods of reducing fuel be used to manage fire in this area of Gibraltar Range National Park

Subjective evaluation of visual quality and simulator sickness of short 360 videos : ITU-T Rec. P.919

Recently an impressive development in immersive technologies, such as Augmented Reality (AR), Virtual Reality (VR) and 360 video, has been witnessed. However, methods for quality assessment have not been keeping up. This paper studies quality assessment of 360 video from the cross-lab tests (involving ten laboratories and more than 300 participants) carried out by the Immersive Media Group (IMG) of the Video Quality Experts Group (VQEG). These tests were addressed to assess and validate subjective evaluation methodologies for 360 video. Audiovisual quality, simulator sickness symptoms, and exploration behavior were evaluated with short (from 10 seconds to 30 seconds) 360 sequences. The following factors' influences were also analyzed: assessment methodology, sequence duration, Head-Mounted Display (HMD) device, uniform and non-uniform coding degradations, and simulator sickness assessment methods. The obtained results have demonstrated the validity of Absolute Category Rating (ACR) and Degradation Category Rating (DCR) for subjective tests with 360 videos, the possibility of using 10-second videos (with or without audio) when addressing quality evaluation of coding artifacts, as well as any commercial HMD (satisfying minimum requirements). Also, more efficient methods than the long Simulator Sickness Questionnaire (SSQ) have been proposed to evaluate related symptoms with 360 videos. These results have been instrumental for the development of the ITU-T Recommendation P.919. Finally, the annotated dataset from the tests is made publicly available for the research communi

Subjective evaluation of visual quality and simulator sickness of short 360° videos: ITU-T Rec. P.919

—Recently an impressive development in immersive technologies, such as Augmented Reality (AR), Virtual Reality (VR) and 360° video, has been witnessed. However, methods for quality assessment have not been keeping up. This paper studies quality assessment of 360° video from the cross-lab tests (involving ten laboratories and more than 300 participants) carried out by the Immersive Media Group (IMG) of the Video Quality Experts Group (VQEG). These tests were addressed to assess and validate subjective evaluation methodologies for 360° video. Audiovisual quality, simulator sickness symptoms, and exploration behavior were evaluated with short (from 10 seconds to 30 seconds) 360° sequences. The following factors’ influences were also analyzed: assessment methodology, sequence

Subjective evaluation of visual quality and simulator sickness of short 360 videos: ITU-T Rec. P.919

Recently an impressive development in immersive technologies, such as Augmented Reality (AR), Virtual Reality (VR) and 360 video, has been witnessed. However, methods for quality assessment have not been keeping up. This paper studies quality assessment of 360 video from the cross-lab tests (involving ten laboratories and more than 300 participants) carried out by the Immersive Media Group (IMG) of the Video Quality Experts Group (VQEG). These tests were addressed to assess and validate subjective evaluation methodologies for 360 video. Audiovisual quality, simulator sickness symptoms, and exploration behavior were evaluated with short (from 10 seconds to 30 seconds) 360 sequences. The following factors' influences were also analyzed: assessment methodology, sequence duration, Head-Mounted Display (HMD) device, uniform and non-uniform coding degradations, and simulator sickness assessment methods. The obtained results have demonstrated the validity of Absolute Category Rating (ACR) and Degradation Category Rating (DCR) for subjective tests with 360 videos, the possibility of using 10-second videos (with or without audio) when addressing quality evaluation of coding artifacts, as well as any commercial HMD (satisfying minimum requirements). Also, more efficient methods than the long Simulator Sickness Questionnaire (SSQ) have been proposed to evaluate related symptoms with 360 videos. These results have been instrumental for the development of the ITU-T Recommendation P.919. Finally, the annotated dataset from the tests is made publicly available for the research community