Avian soundscapes and cognitive landscapes: theory, application and ecological perspectives

The soundscape is proposed as a phenomenological entity with which to investigate environmental complexity. In particular, the avian soundtope, which is defined as a place in which sound is intentionally structured by different bird species, is regarded as an agency acting to achieve several goals. In fact, the soundtope could be viewed as a special case of an eco-field used by birds, not only to establish territorial ownership and patrol an area but also as a means of locating and evaluating the availability of many other material and immaterial resources. The meaning of the multifaceted acoustic pattern produced by bird communities during the breeding season is discussed here under the acoustic niche hypothesis in terms of community coalescence and the permanent establishment of an inter-specific communication network. Furthermore, the spatial and temporal dimensions of a bird soundscape have also been analyzed and discussed in terms of their relationship with environmental proxies. A new Acoustic Complexity Index (ACI), coupled with the implementation (ACI plug-in) of a specific sound editor (WaveSurfer©), is proposed as a way of processing sound data efficiently, thus providing new opportunities to use the bird soundscape signature for landscape characterization and describing the ecological dynamics of long-term monitoring schemes

Candida albicans survival, growth and biofilm formation are differently affected by mouthwashes: an in vitro study

Candida albicans is the most common cause of oral mycoses. The aim of the present study was to investigate in vitro the susceptibility of C. albicans to mouthwashes, in terms of growth, survival and biofilm formation.Candida albicans, laboratory strain SC5314, and 7 commercial mouthwashes were employed: 3 with 0.2% chlorhexidine digluconate; 1 with 0.06% chlorhexidine digluconate and 250 ppm F sodium fluoride; 3 with fluorine-containing molecules. None of the mouthwashes contained ethanol in their formulations. The anti-Candida effects of the mouthwashes were assessed by disk diffusion, crystal violet and XTT assays. By using five protocols combining different dilutions and contact times the mouthwashes were tested against:1) C. albicans growth;2) biofilm formation;3) survival of fungal cells in early, developing and mature Candida biofilm.Chlorhexidine digluconate-containing mouthwashes consistently exhibited the highest anti-Candida activity, irrespective of the protocols employed. Fungal growth, biofilm formation and survival of Candida cells within biofilm were impaired, the effects strictly depending on both the dilution employed and the time of contact.These in vitro studies provide evidence that mouthwashes exert anti-Candida activity against both planktonic and biofilm fungal structures, but to a different extent depending on their composition. This suggests special caution in the choice of mouthwashes for oral hygiene, whether aimed at prevention or treatment of oral candidiasis

The Acoustic Codes: How Animal Sign Processes Create Sound-Topes and Consortia via Conflict Avoidance

In this essay we argue for the possibility to describe the co-presence of species in a community as a consortium built by acoustic codes, using mainly the examples of bird choruses. In this particular case, the consortium is maintained via the sound-tope that different bird species create by singing in a chorus. More generally, the formation of acoustic codes as well as cohesive communicative systems (the consortia) can be seen as a result of plastic adaptational behaviour of the specimen who can solve and avoid conflicts both with conspecifics and with other species in the vicinity. Thus, signrelations appear to resolve potential conflicts, and as a foundation for symbiotic aggregations. The spatio-temporal configuration of consortia—their chronotope—includes several eco-fields as respective to different functions of the participating organisms. Biological study is combined with a semiotic approach that, as we suggest, should be more often used together to effectively describe ecological processes