Acoustic individuality in the hissing calls of the male black grouse (Lyrurus tetrix)

Acoustic individuality may well play a big role during the mating season of many birds. Black grouse (Lyrurus tetrix) produces two different long-distance calls during mating on leks: rookooing and hissing calls. The first one represents low frequency series of bubbling sounds and the second one represents hissing sound. This hissing represents a signal not produced by the syrinx. We analyzed 426 hissing calls from 24 individuals in Finland and Scotland. We conducted cross-validated discrimination analyses (DFA). The discrimination model classified each call with almost 78% accuracy (conventional result) and the validated DFA revealed 71% output, that is much higher than classification by chance (4%). The most important variables were Frequency 95%, 1st Quartile Frequency, Aggregate Entropy and Duration 90%. We also tested whether between individual variation is higher than within individual variation using PIC (Potential for individual coding) and we found that all acoustic parameters had PIC > 1. We confirmed that hissing call of black grouse is individually distinct. In comparison to the signals produced by the syrinx, non-vocal sounds have been studied rarely and according to our knowledge, this is the second evidence of vocal individuality in avian hissing sounds which are not produced by syrinx. Individuality in the vocalization of the male black grouse may aid females in mating partner selection, and for males it may enable competitor recognition and assessment. Individually distinct hissing calls could be of possible use to monitor individuals on leks. Such a method could overcome problems during traditional monitoring methods of this species, when one individual can be counted multiple times, because catching and traditional marking is problematic in this species.

Noise in Telecommunication: Different Types and Methods of dealing with Noise

This article discusses noise in telecommunications: different types and methods of dealing with noise. Noise is arguably a very hated problem because it can interfere with the quality of signal reception and also the reproduction of the signal that will be transmitted. Not only that, but noise can also limit the range of the system to a certain emission power and can affect the sensitivity and sensitivity of the reception signal. Even in some cases, noise can also result in a reduction in the bandwidth of a system. Of course, we've all felt how annoying the noise effect is. For example, when listening to the radio, a hissing sound appears on the loudspeaker due to noise. To overcome noise, it is divided into passive noise control and active noise control. Passive noise control is an effort to overcome noise using components that do not require power. Generally passive noise control uses soundproof materials that act as insulation against noise. The method most commonly used to overcome noise is through increasing the gain. The noise is generally in a specific sound area. Hiss is on high frequencies, while noise and hum are on low frequencies. This is the principle underlying the noise reduction method.

The Magnitude and Determinants of Tinnitus among Health Science Students at King Khalid University

Background. Tinnitus is a symptom that is defined as a subjective perception of noise in an absence of external sound. It is an indicator of auditory system abnormalities. It can also be present in individuals without any hearing abnormalities. Difficulty to consternate, insomnia, and decreased speech discrimination are the most common symptoms related to tinnitus. Aim. To assess the magnitude and pattern with determinants of tinnitus among health science students at King Khalid University. Methodology. A descriptive cross-sectional survey was conducted targeting all accessible students in health science colleges in King Khalid University which is the main university in the Aseer region, south of Saudi Arabia. Students were included consecutively from different faculties and different grades. Data were collected through a self-administered prestructured questionnaire, which was distributed and recollected the next day. Tinnitus was screened using an adapted form of the National Health and Nutrition Examination Survey (NHANES). Results. A total sample of 400 students have been included with their ages ranging from 18 to 30 years with a mean age of 22 ± 1.8 years), and 28.5% of the students recorded positive findings. Tinnitus was bilateral among 51.8% of students, and 44.7% of tinnitus students hear buzzing sound while 21.1% have hissing sound and 10.5% had pulsating sound. Among 46.5% of students with tinnitus, the heard sound was of moderate loudness and intermittent among 64.9% of them. Conclusions and Recommendations. In conclusion, the study revealed that just more than a quarter of students complained of tinnitus which was bilateral among half of them. Tinnitus frequency was mainly moderate in intensity and intermittent. Having ear problems, loud sounds, and allergy were the most important predictors of having Tinnitus.

P.093 Pulsatile tinnitus due to obstruction of transverse sinus by tentorial meningioma

Background: The etiology and treatment of pulsatile tinnitus is difficult and there are different causes for it. To our knowledge, an obstruction of the transverse sinus due to tentorial meningioma has not been reported. Methods: A 66 year old female presented a year ago with a sudden onset of a hissing sound in her ear which has persisted since. Neurologically she was intact. She was seen by otolaryngology who identified no cause for her tinnitus. A CT scan and MRI showed a tentorial meningioma on the right side with partial obstruction of the transverse sinus with evidence of partial chronic thrombus. Results: Removal of the meningioma with decompression of the transverse sinus resulted in immediate disappearance of the pulsatile tinnitus. Conclusions: This report can be added to the etiology of the difficult entity of pulsatile tinnitus particularly as it relates to its management.

Narcolepsy with Tinnitus Aura: Interpretation

A fifty-five year old man was admitted to our ward for evaluation of narcoleptic-cataplectic attacks which were signaled by a “hissing sound like high pressure steam leaking out of a pipe.” This tinnitus was exclusively localized to the right ear. It started about sixty-to-ninety seconds before the cataplectic episode (affecting mostly the jaw muscles) and lasted through part of it as it became progressively louder toward the end and ceased abruptly. It is postulated that, along with the collapse of tonic musculature of the mandible, a decrease of proprioceptive tone also affected the tensor tympani muscle leaving the middle ear vulnerable to internally generated noise. We further postulate that tinnitus was finally arrested by the generation of phasic bursts of contraction of the tensor tympani and/or the stapedius muscle at a later stage of cataplexy.

XXXV. On some of the products of the destructive distillation of boghead coal.─Part II

The first part of this paper contained the results of the examination of those hydrocarbons found in the distillate from the Torbane-hill mineral which were remarkable for their resistance to the action of monohydrated nitric and sulphuric acids. It was shown that, when in a state of purity, they possessed the composition, boiling-point, and density in the fluid and gaseous states, of the radicals of the ethylic class of alcohols. The present communication enters on the study of a group of substances as distinguished by the mobility, as the former are by the fixity of their hydrogen atoms. The examination of them has involved more labour than was experienced with their companion hydrocarbons; and the quantities obtained being necessarily small, even when working on a considerable scale, it has been impossible, at present, to do more than determine their constitution. The study of their combinations and decompositions is therefore necessarily deferred. Up to the present time we have been unacquainted with methods for the proximate analysis of complex mixtures such as that under study. It was necessary, therefore, to devise some plan for the purpose. The presence of benzole and its homologues was almost a matter of certainty, as they appear to be formed in all processes where coaly or bituminous matters are subjected to destructive distillation. In order to separate the hydrocarbons, the following method was adopted. Four ounces of bromine being placed in a large and well-stoppered flask, about eight volumes of water were added. The naphtha boiling in the fourteenth rectification between 71° and 77° Centigrade, was then added in very small portions, the whole being violently agitated after each addition. As the bromine, from its superior density, lay at the bottom of the water and the naphtha at the top, it will be seen that combination could not take place until the flask was shaken, at which time they united with a sharp hissing sound and a rise of temperature. The entire quantity of naphtha was absorbed by the bromine, forming a dense oil, becoming paler and at last colourless as the hydrocarbon increased in quantity. To ensure a definite product more bromine was used, so as to obtain a red oil, the excess being afterwards removed by agitation with mercury. During the process some substance is generated, acting powerfully on the eyes and causing a flow of tears; it is always present in the brominated oil, even when every trace of free bromine is removed. If the brominated oil be kept for some time in contact with water, it will be found that a third layer will make its appearance beneath the oil; this will be described hereafter.