Real-time auralisation system for virtual microphone positioning

A computer application was developed to simulate the process of microphone positioning in sound recording applications. A dense, regular grid of impulse responses pre-recorded on the region of the room under study allowed the sound captured by a virtual mi- crophone to be auralised through real-time convolution with an anechoic stream representing the sound source. Convolution was performed using a block-based variation on the overlap-add method where the summation of many small sub- convolutions produced each block of output data samples. As the applied RIR filter varied on successive audio output blocks, a short cross fade was applied to avoid glitches in the audio. The maximum possible length of impulse response applied was governed by the size of audio processing block (hence la- tency) employed by the program. Larger blocks allowed a lower processing time per sample. At 23.2ms latency (1024 samples at 44.1kHz), it was possible to apply 9 second impulse responses on a standard laptop computer.Fundação para a Ciência e a Tecnologia (FCT

On the adaptation to non-individualized HRTF auralisations: A longitudinal study

Auralisations with HRTFs are an innovative tool for the reproduction of acoustic space. Their broad applicability depends on the use of non-individualised models, but little is known on how humans adapt to these sounds. Previous findings have shown that simple exposure to non-individualised virtual sounds did not provide a quick adaptation, but that training and feedback would boost this process. Here, we were interested in analyzing the long-term effect of such training-based adaptation. We trained listeners in azimuth and elevation discrimination in two separate experiments and retested them immediately, one hour, one day, one week and one month after. Results revealed that, with active learning and feedback, all participants lowered their localization errors. This benefit was still found one month after training. Interestingly, participants who had trained previously with elevations were better in azimuth localization and vice-versa. Our findings suggest that humans adapt easily to new anatomically shaped spectral cues and they are able to transfer that adaptation to non-trained sounds.(undefined

On the improvement of localization accuracy with nonindividualized HRTF-based sounds

Auralization is a powerful tool to increase the realism and sense of immersion in Virtual Reality environments. The Head Related Transfer Function (HRTF) filters commonly used for auralization are non-individualized, as obtaining individualized HRTFs poses very serious practical difficulties. It is therefore extremely important to understand to what extent this hinders sound perception. In this paper, we address this issue from a learning perspective. In a set of experiments, we observed that mere exposure to virtual sounds processed with generic HRTF did not improve the subjects’ performance in sound source localization, but short training periods involving active learning and feedback led to significantly better results. We propose that using auralization with non-individualized HRTF should always be preceded by a learning period.Fundação para a Ciência e a Tecnologia (FCT)FEDE

Methadone Intoxication in a Child: Toxic Encephalopathy?

Methadone is used in the treatment of opioid addiction. Acute intoxication can lead to severe consequences and can even be lethal. In several case reports and small series, a presumably toxic leukoencephalopathy is described resulting from inhalation of heroin. We present the case of a 3-year-old boy who ingested methadone accidentally. In a coma with acute obstructive hydrocephalus owing to massive cerebellar edema and supratentorial lesions, he was successfully treated with methylprednisolone and cerebrospinal fluid external drainage. To our knowledge, this is the first report of an encephalopathy associated with synthetic opioid intoxication

Avaliação da qualidade dos produtos, infraestrutura e serviços em feiras e mercados orgânicos localizados em Brasília ? DF.

É notório que o interesse em formas de produção consideradas alternativas se intensificou, visando atender à crescente demanda pelos produtos saudáveis e sustentáveis. O presente estudo tem como eixo principal as feiras locais e um mercado de produtos orgânicos. O objetivo foi avaliar a percepção dos feirantes e produtores sobre a qualidade dos produtos, a infraestrutura e os serviços prestados por estes estabelecimentos em Brasília-DF. Para obtenção dos dados foram realizadas entrevistas com feirantes guiadas pelo uso de questionário. Verificou-se que a maioria dos feirantes tem renda exclusivamente da venda da produção orgânica. Quanto à qualidade do produto, esses profissionais julgam importante a higienização e cuidados para manter a boa aparência do alimento. Atenção e cordialidade foram consideradas atributos muito importantes, na percepção dos feirantes, na relação dos mesmos com a clientela para manter a fidelidade. Abstract: It?s well known that the interest in alternative forms of production have intensified, in order to attend the growing market demand for healthier and sustainable products. As the main axis of this study, local fairs and organic market were considered. The objective was to evaluate those fair workers and producer?s perception towards the product?s quality, the local infrastructure and the establishment?s services. Data collection was performed by interviews guided by a questionnaire application. The results show that the majority of workers have incomes exclusively from the sale of organic production. Regarding product?s quality, these professionals consider as important the product?s sanitization and the care to maintain the product?s good appearance. Attention and cordiality were considered very important for fair workers in their relationship with consumers to maintain fidelity

Biolistic-mediated genetic transformation of cowpea (Vigna unguiculata) and stable Mendelian inheritance of transgenes.

Made available in DSpace on 2018-05-24T00:41:09Z (GMT). No. of bitstreams: 1 SP19591ID30693.pdf: 573782 bytes, checksum: 13f83a2f9dcd4695291802338c95159d (MD5) Previous issue date: 2009-01-1

Occurrence of Aggregatibacter actinomycetemcomitans in Brazilian indians from Umutina Reservation, Mato Grosso, Brazil

Aggregatibacter actinomycetemcomitans is associated with periodontal disease, especially localized aggressive periodontitis, produces a potent leukotoxin and its distribution is influenced by ethnic characteristics of the population. Objective: Using culture and polymerase chain reaction (PCR) techniques, this study evaluated the occurrence of this microorganism and the distribution of leukotoxic strains isolated from Indians belonging to the Umutima Reservation, Mato Grosso, Brazil. MATERIAL AND METHODS: Forty-eight native Brazilians with gingivitis and 38 with chronic periodontitis, belonging to Umutina, Paresi, Bororo, Bakairi, Kayabi, Irantxe, Nambikwara and Terena ethnicities, were studied. Subgingival, supragingival and saliva samples of each patient were collected and transferred to VMGA III medium and to ultra pure Milli Q water. Bacteria were grown on TSBV agar and incubated in anaerobiosis (90% N2 + 10% CO2) at 37ºC for 72 h. The presence of the ltx promoter was determined by PCR, and a 530 bp deletion in the promoter was evaluated by using specific primers. RESULTS: A. actinomycetemcomitans was isolated from 8.33% of saliva, supragingival and subgingival samples from patients with gingivitis and from 18.42% of saliva and supragingival biofilm, and 26.32% subgingival biofilm from patients with chronic periodontitis. By PCR, the bacterial DNA was detected in 8.33% of saliva, supragingival and subgingival biofilms from patients with gingivitis and from 23.68% of saliva, 28.95% supragingival biofilm and 34.21% subgingival biofilm from patients with periodontitis. All strains were grouped as non-JP2 clones based on the absence of deletion in the leukotoxin promoter. Differences among the microbial and clinical parameters in patients were analyzed by using the Mann-Whitney, Chi-square or Fisher's exact tests. CONCLUSIONS: The present results suggest that A. actinomycetemcomitans can be related to the attachment loss in this population, but the presence of minimally leukotoxic strains, as well as its role in the pathogenesis of the periodontitis in these native Brazilians need to be further investigated