Predictability-Based Source Segregation and Sensory Deviance Detection in Auditory Aging

When multiple sound sources are present at the same time, auditory perception is often challenged with disentangling the resulting mixture and focusing attention on the target source. It has been repeatedly demonstrated that background (distractor) sound sources are easier to ignore when their spectrotemporal signature is predictable. Prior evidence suggests that this ability to exploit predictability for foreground-background segregation degrades with age. On a theoretical level, this has been related with an impairment in elderly adults’ capabilities to detect certain types of sensory deviance in unattended sound sequences. Yet the link between those two capacities, deviance detection and predictability-based sound source segregation, has not been empirically demonstrated. Here we report on a combined behavioral-EEG study investigating the ability of elderly listeners (60–75 years of age) to use predictability as a cue for sound source segregation, as well as their sensory deviance detection capacities. Listeners performed a detection task on a target stream that can only be solved when a concurrent distractor stream is successfully ignored. We contrast two conditions whose distractor streams differ in their predictability. The ability to benefit from predictability was operationalized as performance difference between the two conditions. Results show that elderly listeners can use predictability for sound source segregation at group level, yet with a high degree of inter-individual variation in this ability. In a further, passive-listening control condition, we measured correlates of deviance detection in the event-related brain potential (ERP) elicited by occasional deviations from the same spectrotemporal pattern as used for the predictable distractor sequence during the behavioral task. ERP results confirmed neural signatures of deviance detection in terms of mismatch negativity (MMN) at group level. Correlation analyses at single-subject level provide no evidence for the hypothesis that deviance detection ability (measured by MMN amplitude) is related to the ability to benefit from predictability for sound source segregation. These results are discussed in the frameworks of sensory deviance detection and predictive coding.

Determinants of an Effective Solid Wastes Collection at the Workplace: the Experience of the Council for Scientific and Industrial Research-Institute of Industrial Research, Accra, Ghana

The inefficient collection of solid wastes is a global phenomenon that has received attention in recent years for the ever-increasing annual waste generation records. However, indicators to the effective application of the amassing routs are missing. Hence, the generally accepted source-sorting model was explored to identify the determinants that will enhance source separation of wastes at the workplace. This paper presents a foremost report on the indicators to an effective operation of solid wastes source segregation. A quantitatively examined data was collected in sixty-six working days during a monitoring and evaluation process of twenty sets of twin-dustbins that were located at the study area. The generated solid wastes were commonly sorted (65%) in comparison with the mixed collection. Most of the wastes were separated on the third month (80%) of education compared to the first (54%) and second months (61%). Wednesday displayed the working day with the utmost sorted wastes (73%) compared to the other days. All dustbins recorded impressive sorting at the different locations in the Institute. A little over one thousand Ghana cedis savings was made in the first year. Tested null hypothesis showed that, duration and timing of continuous education were significant determinants of the efficient source segregation, relative to the dustbin locations. Therefore, the daily education of waste generators on how to separate wastes at source and the economic benefits will enhance source separation irrespective of the location.

Application of Multi Criteria Decision Making in Adopting Suitable Solid Waste Management Model for an Urban Local Body. Case Study of Bhubaneswar City of Odisha, India

A practical approach to deal with the municipal solid waste at hand needs the adoption of a suitable model and an understanding of the required processes to manage it effectively. A case study of Bhubaneswar City/ Municipal Corporation of Odisha in India, focused on the development of a suitable model based on approaches like Process of elimination, Strength, Weakness, Opportunity and Threat (SWOT) analysis, Mathematical analysis, Analytical Hierarchy Process and the Test of sustainability. The study focused on the processes in Municipal Solid Waste (MSW) value chain like waste generation, primary source storage, collection, secondary storage, transportation, processing and disposal. A two by two matrix model was adopted to arrive at a suitable disposal model mapped with the source segregation. The Urban Local Body (ULB) analysed Analytical Hierarchy Process (AHP) as one of the criteria to select suitable Collection, Transportation and Disposal Model based on Technical, Economic, Social and Environmental considerations .The mathematical analysis involved Pair-wise Comparison Matrix for the quantitative variables while qualitative variables were examined by Analytical Hierarchy Process (AHP). The economic factor dominated the decision making; ‘street dumping and street sweeping’ got an upper ranking in the final matrix analysis of the collection and Transportation plan and ‘incineration’ dominated the decision making for the disposal plan. The limitation of the study showed that the application of mathematical model to find out optimum Municipal Solid Waste (MSW) Model does not accommodate qualitative variables. Therefore, SWOT analysis and sustainability studies were examined to arrive at the best possible model. SWOT criteria drew upon the work environment with respect to financial position of the Urban Local Body, Not in my backyard (NIMBY) factor, Private Public Partnership (PPP) mode aspirants, availability of mature technology and threat in factors like adverse regulatory order, disruptive technologies and the lack of political will. The test of sustainability based on the proposed model passed through the test of capability and constraint study, social acceptance, regulatory compliance, and ground level feasibility. Based on multiple criteria in decision making, the study found that ideally Bhubaneswar should adopt a model where source segregation with door to door collection of waste facility is given top priority. Decentralization of waste disposal and cluster approach of cities and towns nearby to curb the waste menace and facilitate the waste to go the fuel way looked sustainable and achievable. At the same time, addressing the Not in my backyard (NIMBY) factor by earmarking land bank for waste disposal and collection of cesses from the city inhabitants could generate enough financial resources for its sustainability. This research unbolts discussions with respect to the challenges presented by the Not in my backyard (NIMBY) factor, finding suitable landfill sites for solid waste disposal, interference of disruptive technologies and the change in leadership not owning up to responsibilities or revoking the previously established management practices. Sustainability studies should help all stakeholders to participate harmoniously with a common goal of clean city and striving for a better planet. Similarly, the comparative matrix based on the scientific, financial, social and ecological considerations were applied to the disposal plan to develop a fitting model for the Urban Local Body (ULB). The study ascertained that Bhubaneswar should have source segregation with door to door collection facility and may need decentralized composting facility centres to handle the biodegradable wastes. The plastic wastes may be used for Waste to Fuel or for road making. The non-degradable may go to land fill or Waste to Energy plant with cluster approach combining nearby Cuttack and Khurdha districts to meet the waste requirement of 550 tonnes per day to sustain the plant. At the same time, it should collect cess from the city habitants to generate enough financial resources for sustainability. It should earmark the land-bank for waste processing facilities as it faces serious Law and Order problems due to Not in my backyard (NIMBY) factor.

Economic and environmental consequences of implementing an EU model for collecting and separating wastes system in Lebanon

In this study, we examine the economic and environmental significance associated with the implementation of an EU waste-separated collection scheme in a developing context – Lebanon. Two scenarios, S1 and S2, representing different intensities of source segregation were analysed. In S1, the average source segregation intensity reached 25% and 13% for the Italian test area and Lebanese test area, respectively. In S2, source segregation intensity increased to 48% and 68% for the Italian and Lebanese test areas, respectively. Passing from S1 to S2 increased collection costs significantly, up to 44% with greater increases in the Italian test area where labour cost is higher. In both areas, environmental impacts decreased with greater source segregation intensity. Savings in the climate change impact and stratospheric ozone depletion potential were lower under the Lebanese test area in comparison with the Italian test area. In contrast, savings in freshwater eutrophication and acidification impact were lower for the Italian test area. The increase in the source segregation intensity resulted in maximum savings for the depletion of abiotic resources, 74% to 77% and 79% to 80% in a developing and developed context, respectively.

Commercial and household food waste separation behaviour and the role of Local Authority: a case study

Purpose Source segregation of food waste is one of the major challenges that inhibit food waste recycling around the world. Therefore, the purpose of this study was to investigate the role of the local authority to implement regulations and encourage an increase in the source separation of food waste within both commercial premises and households, and identifying any gaps that exist in public awareness. Methods This study was conducted by the Cork County Council in 568 commercial premises and 1362 houses in County Cork, Ireland. This study also included investigations of public and private civic amenity sites and waste collectors that collect kerb side waste located within the region. The interviewee’s responses were documented and a database has been prepared and analysed. Results Integrated strategy is crucial to roll out food waste bin within a community for successful implementation of source segregation of food waste. This strategy should involve a dedicated team from the local authority who continue to visit, monitor and co-ordinate the activities of local authorities, waste collectors, civic amenity sites and public to implement and enforce the food waste regulations. In addition to organising appropriate infrastructure for recycling of food waste, continuous awareness raising through education, leaflets and local and national media is also crucial. Conclusion The role of local authorities should include facilitating the development of appropriate facilities such as composting, anaerobic digestion within communities and to encourage communities to take ownership of these facilities and reuse the resultant material within the local area.

Effect of Dual-Carrier Processing on the Intelligibility of Concurrent Vocoded Sentences

Purpose The goal of this study was to examine the role of carrier cues in sound source segregation and the possibility to enhance the intelligibility of 2 sentences presented simultaneously. Dual-carrier (DC) processing (Apoux, Youngdahl, Yoho, & Healy, 2015) was used to introduce synthetic carrier cues in vocoded speech. Method Listeners with normal hearing heard sentences processed either with a DC or with a traditional single-carrier (SC) vocoder. One group was asked to repeat both sentences in a sentence pair (Experiment 1). The other group was asked to repeat only 1 sentence of the pair and was provided additional segregation cues involving onset asynchrony (Experiment 2). Results Both experiments showed that not only is the “target” sentence more intelligible in DC compared with SC, but the “background” sentence intelligibility is equally enhanced. The participants did not benefit from the additional segregation cues. Conclusions The data showed a clear benefit of using a distinct carrier to convey each sentence (i.e., DC processing). Accordingly, the poor speech intelligibility in noise typically observed with SC-vocoded speech may be partly attributed to the envelope of independent sound sources sharing the same carrier. Moreover, this work suggests that noise reduction may not be the only viable option to improve speech intelligibility in noise for users of cochlear implants. Alternative approaches aimed at enhancing sound source segregation such as DC processing may help to improve speech intelligibility while preserving and enhancing the background.

Olfactory object recognition based on fine-scale stimulus timing in Drosophila

SUMMARYOdorants of behaviorally relevant objects (e.g., food sources) intermingle with those from other sources. Therefore, to sniff out whether an odor source is good or bad – without actually visiting it – animals first need to segregate the odorants from different sources. To do so, animals could use temporal cues, since odorants from one source exhibit correlated fluctuations, while odorants from different sources are less correlated. However, it remains unclear whether animals can rely solely on temporal cues for odor source segregation. Here we show that 1) flies can use a few milliseconds differences in odorant arrival to segregate a target odorant from a binary mixture, 2) segregation does not improve when the target odorant arrives first, and 3) segregation works for odorants with innate, as well as learned valences. These properties of odor segregation parallel those of concurrent sound segregation and figure-ground segregation by onset asynchrony in humans.