Spatial Hearing with Incongruent Visual or Auditory Room Cues.

In day-to-day life, humans usually perceive the location of sound sources as outside their heads. This externalized auditory spatial perception can be reproduced through headphones by recreating the sound pressure generated by the source at the listener's eardrums. This requires the acoustical features of the recording environment and listener's anatomy to be recorded at the listener's ear canals. Although the resulting auditory images can be indistinguishable from real-world sources, their externalization may be less robust when the playback and recording environments differ. Here we tested whether a mismatch between playback and recording room reduces perceived distance, azimuthal direction, and compactness of the auditory image, and whether this is mostly due to incongruent auditory cues or to expectations generated from the visual impression of the room. Perceived distance ratings decreased significantly when collected in a more reverberant environment than the recording room, whereas azimuthal direction and compactness remained room independent. Moreover, modifying visual room-related cues had no effect on these three attributes, while incongruent auditory room-related cues between the recording and playback room did affect distance perception. Consequently, the external perception of virtual sounds depends on the degree of congruency between the acoustical features of the environment and the stimuli.

Comparison of lignin extraction processes: Economic and environmental assessment.

This paper presents the technical-economic and environmental assessment of four lignin extraction processes from two different raw materials (sugarcane bagasse and rice husks). The processes are divided into two categories, the first processes evaluates lignin extraction with prior acid hydrolysis step, while in the second case the extraction processes are evaluated standalone for a total analysis of 16 scenarios. Profitability indicators as the net present value (NPV) and environmental indicators as the potential environmental impact (PEI) are used through a process engineering approach to understand and select the best lignin extraction process. The results show that both economically and environmentally process with sulfites and soda from rice husk presents the best results; however the quality of lignin obtained with sulfites is not suitable for high value-added products. Then, the soda is an interesting option for the extraction of lignin if high quality lignin is required for high value-added products at low costs.

A review of the clinical management of mobile teeth.

The clinical management of mobile teeth can be a perplexing problem, especially if the underlying causes for that mobility have not been properly diagnosed. In some cases, mobile teeth are retained because patients decline multidisciplinary treatment that might otherwise include strategic extractions. This article discusses the relationship between occlusion and tooth mobility with an emphasis on identifying differences between increased mobility and increasing mobility. The indications, contraindications, and basic principles of tooth splinting are also reviewed. Provisional and definitive splints are defined and described with their respective occlusal considerations. Some mobile teeth can be treated through occlusal equilibration alone (primary occlusal trauma). Whereas mobile teeth with a compromised periodontium can be stabilized with the aid of provisional and/or definitive splinting (secondary occlusal trauma). It is important to consider splint therapy, because it may not only improve the prognosis of teeth, but may actually enhance the stability of the final prosthodontic treatment. The ultimate goal of successful management of mobile teeth is to restore function and comfort by establishing a stable occlusion that promotes tooth retention and the maintenance of periodontal health.

Evaluación radioisotópica de la función ventricular izquierdo en relacion a oxigeno-terapia en pacientes hipoxemicos crónicos / Radioisotopic evaluation of the left ventricular fuction in relation to oxygetherapy in chronic hypoxemic patient

La finalidad de este estudio fue evaluar la fracción de eyección del ventrículo izquierdo (F.E.V.I.) y su motilidad después de la administración aguda de O2 en pacientes hipoxémicos crónicos de causa respiratoria. Once hombres con una edad x de 58 años con Pa O2 < 60 mmHg fueron evaluados con ventriculografía isotópica pre y post oxigenoterapia con Fi O2 de 0.18-0.30, midiendo gases arteriales, también pre y post oxigenoterapia. En forma global la F.E.V.I. medida por ventriculografía isotópica no cambió significativamente, aunque analizada individualmente, en 2 pacientes aumentó y en 4 disminuyó más del 5%, porcentaje considerado significativo para casos aislados. Aunque la respuesta individual de la F.E.V.I. a la oxigenoterapia fue variable, en la mayoria de los enfermos estudiados (5 de los 11 casos) no cambió significativamente con la administración de oxígeno