scholarly journals Dolphin-Inspired Target Detection for Sonar and Radar

2015 ◽  
Vol 39 (3) ◽  
pp. 319-332 ◽  
Author(s):  
Timothy Leighton ◽  
Paul White

Abstract Gas bubbles in the ocean are produced by breaking waves, rainfall, methane seeps, exsolution, and a range of biological processes including decomposition, photosynthesis, respiration and digestion. However one biological process that produces particularly dense clouds of large bubbles, is bubble netting. This is practiced by several species of cetacean. Given their propensity to use acoustics, and the powerful acoustical attenuation and scattering that bubbles can cause, the relationship between sound and bub-ble nets is intriguing. It has been postulated that humpback whales produce ‘walls of sound’ at audio frequencies in their bubble nets, trapping prey. Dolphins, on the other hand, use high frequency acous-tics for echolocation. This begs the question of whether, in producing bubble nets, they are generating echolocation clutter that potentially helps prey avoid detection (as their bubble nets would do with man-made sonar), or whether they have developed sonar techniques to detect prey within such bubble nets and distinguish it from clutter. Possible sonar schemes that could detect targets in bubble clouds are proposed, and shown to work both in the laboratory and at sea. Following this, similar radar schemes are proposed for the detection of buried explosives and catastrophe victims, and successful laboratory tests are undertaken.

2019 ◽  
Vol 30 (2) ◽  
pp. 47-54
Author(s):  
M.R. Ferrari ◽  
E.J. Greizerstein ◽  
L. Poggio

In this work the relationship between genome size of Glandularia species and the meiotic configurations found in their hybrids are discussed. Glandularia incisa (Hook.) Tronc., growing in two localities of Corrientes and Córdoba provinces, Argentina, with different ecological conditions, showed inter-population variability of the 2C-value. The DNA content found in the Corrientes locality (2.41 pg) was higher than that obtained in the Córdoba locality (2.09 pg) which has more stressful environmental conditions than the former. These values are statistically different from those that were found in Glandularia pulchella (Sweet) Tronc. from Corrientes (1.43 pg) and in Glandularia perakii Cov. et Schn from Córdoba (1.47 pg). The DNA content of the diploid F1 hybrids, G. pulchella × G. incisa and G. perakii × G. incisa, differed statistically from the DNA content of the parental species, being intermediate between them. Differences in the frequency of pairing of homoeologous chromosomes were observed in the hybrids; these differences cannot be explained by differences in genome size since hybrids with similar DNA content differ significantly in their meiotic behavior. On the other hand, the differences in the DNA content between the parental species justify the presence of a high frequency of heteromorphic open and closed bivalents and univalents with different size in the hybrids. Key words: Intra-specific DNA content variability, homoeologous pairing, heteromorphic bivalents


2021 ◽  
Vol 9 (02) ◽  
pp. 965-985
Author(s):  
Marie Mvu Njoya ◽  
◽  
Ambahe Duplex Rufin ◽  

In the outskirts of the northern periphery of Mbam and Djerem National Park, agro-pastoral conflicts have become very frequent in recent years. The resulting damage is so surprising that it leaves no one indifferent. Unfortunately, many writings analyze the causes of these agro-pastoral conflicts without, however, dwelling on the fodder resources which constitute not only the staple food of cattle but also one of the primary factors of these antagonisms. To overcome this knowledge gap, the authors adopted the survey method in order to identify, on the one hand, the attributes of agro-pastoral conflicts and the plant species consumed in all seasons by cattle on the northern periphery of the PNMD and, on the other hand, the relationship between these forage species with the frequency of agro-pastoral conflicts according to the protagonists and the seasons. Thus, from field observations and a questionnaire sent to 44 breeders and 103 farmers in four control villages, it results, after processing the data, that the high frequency of conflicts experienced by the farmers in the dry season (35.9 %) and especially by the breeders (70.5%) is due to the location of the forage species prized in this season at the bottom of the valleys where the herds are concentrated and compete. On the other hand, the low frequency of conflicts experienced during the rainy season especially by breeders, except in Mbitom, is more justified by the extension of fodder registers to woody leaves from the start of this season. Finally, the fodder fields of Brachiaria constitute a partial solution to the shortage of pastures even if it sometimes gives rise to new conflicts between herders.


2020 ◽  
Vol 50 (6) ◽  
pp. 1504-1512
Author(s):  
Güler ÖZTÜRK ◽  
Kazime Gonca AKBULUT ◽  
Şevin GÜNEY

The aim of this review is to summarize current studies on the relationship between melatonin and aging. Nowadays, age-related diseases come into prominence, and identifying age-related changes and developing proper therapeutic approaches are counted as some of the major issues regarding community health. Melatonin is the main hormone of the pineal gland. Melatonin is known to influence many biological processes in the body, including circadian rhythms, the immune system, and neuroendocrine and cardiovascular functions.Melatoninrhythms also reflect the biological process of aging. Aging is an extremely complex and multifactorial process. Melatonin levels decline considerably with aging and its decline is associated with several age-related diseases. Aging is closely associated with oxidative damage and mitochondrial dysfunction. Free radical reactions initiated by the mitochondria constitute the inherent aging process. Melatonin plays a pivotal role in preventing age-related oxidative stress. Coronavirus disease 2019 (COVID-19) fatality rates increase with chronic diseases and age, where melatonin levels decrease. For this reason, melatonin supplementation in elderly could be beneficial in COVID-19 treatment. Therefore, studies on the usage of melatonin in COVID-19 treatment are needed.


2011 ◽  
Vol 1 (5) ◽  
pp. 28
Author(s):  
Andre Wallet

The study of navigation conditions in the Seine estuary has led to scale model tests which are now being carried out by the NEYBPIC Laboratory, Grenoble; for the Port of Rouen Authority. In order to calibrate the model correctly, that is to say to ensure that the natural conditions would be reproduced on the model, it was necessary to carry out laboratory studies on the sand from the estuary bed to determine the solid discharge of this material for definite hydraulic conditions. This was necessary because, while at some distance above the bed direct measurements of the solid transport are relatively easy to make in nature by means of samples, they are practically impossible in the immediate neighborhood of the bottom when the sand is fine, as is the case in the Seine estuary. On the other hand, by taking certain precautions it is possible to measure the solid discharge in the immediate neighborhood of the bottom when.the transport of sand is studied in the laboratory. The two methods, direct measurements of the suspended load in nature and measurements of solid discharge near the bottom in the laboratory therefore complement one another. However, it seemed interesting to justify this method by comparing the results where nature and the laboratory coincide, i.e. for material in suspension. This paper gives details on the procedure followed for these laboratory tests on an experimental canal. The main results of these tests will be reviewed by examining the relationship between the concentration in the neighbourhood of the bottom and the solid discharge on the one hand, and the bottom shear stress on the other.


Cells ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1615
Author(s):  
Tatsunori Osone ◽  
Naohiro Yoshida

MicroRNAs are important genes in biological processes. Although the function of microRNAs has been elucidated, the relationship between the sequence and the disease is not sufficiently clear. It is important to clarify the relationship between the sequence and the disease because it is possible to clarify the meaning of the microRNA genetic code consisting of four nucleobases. Since seed theory is based on sequences, its development can be expected to reveal the meaning of microRNA sequences. However, this method has many false positives and false negatives. On the other hand, disease-related microRNA searches using network analysis are not based on sequences, so it is difficult to clarify the relationship between sequences and diseases. Therefore, RNA–RNA interactions which are caused by hydrogen bonding were focused on. As a result, it was clarified that sequences and diseases were highly correlated by calculating the electric field in microRNA which is considered as the torus. It was also suggested that four diseases with different major classifications can be distinguished. Conventionally, RNA was interpreted as a one-dimensional array of four nucleobases, but a new approach to RNA from this study can be expected to provide a new perspective on RNA-RNA interactions.


2020 ◽  
Vol 24 (04) ◽  
pp. 762-769
Author(s):  
Carlos Barros de Araújo ◽  
◽  
Shaka Nóbrega Marinho Furtado ◽  
Gustavo Henrique Calazans Vieira ◽  
Cássio Rachid Simões ◽  
...  

Animal communication is related to many biological processes, and its investigation may help elucidate many aspects of an organism. If in the one hand, animal communication might be seen as a biological process, in the other, sound is a physical phenomenon, so that the understanding of animal communication depends on processes that go beyond biology itself. Here we aim to interlace concepts of Physics, Ecology, and communication to better operationalize the concept of acoustic niche. The study of the relationships between the communication problems (i.e. transmission, semantics and effectiveness), the physical properties of sound (frequency, intensity and time), and ecological aspects of communication, permits a better understanding of the acoustic niche and its evolution.


2017 ◽  
Vol 11 (2) ◽  
Author(s):  
Yueyin Zhou ◽  
Andreas Wagner ◽  
Thomas Wunderlich ◽  
Peter Wasmeier

AbstractThe technique of Image Assisted Total Stations (IATS) has been studied for over ten years and is composed of two major parts: one is the calibration procedure which combines the relationship between the camera system and the theodolite system; the other is the automatic target detection on the image by various methods of photogrammetry or computer vision. Several calibration methods have been developed, mostly using prototypes with an add-on camera rigidly mounted on the total station. However, these prototypes are not commercially available. This paper proposes a calibration method based on Leica MS50 which has two built-in cameras each with a resolution of 2560 × 1920 


2020 ◽  
Vol 29 (3) ◽  
pp. 429-435
Author(s):  
Patricia C. Mancini ◽  
Richard S. Tyler ◽  
Hyung Jin Jun ◽  
Tang-Chuan Wang ◽  
Helena Ji ◽  
...  

Purpose The minimum masking level (MML) is the minimum intensity of a stimulus required to just totally mask the tinnitus. Treatments aimed at reducing the tinnitus itself should attempt to measure the magnitude of the tinnitus. The objective of this study was to evaluate the reliability of the MML. Method Sample consisted of 59 tinnitus patients who reported stable tinnitus. We obtained MML measures on two visits, separated by about 2–3 weeks. We used two noise types: speech-shaped noise and high-frequency emphasis noise. We also investigated the relationship between the MML and tinnitus loudness estimates and the Tinnitus Handicap Questionnaire (THQ). Results There were differences across the different noise types. The within-session standard deviation averaged across subjects varied between 1.3 and 1.8 dB. Across the two sessions, the Pearson correlation coefficients, range was r = .84. There was a weak relationship between the dB SL MML and loudness, and between the MML and the THQ. A moderate correlation ( r = .44) was found between the THQ and loudness estimates. Conclusions We conclude that the dB SL MML can be a reliable estimate of tinnitus magnitude, with expected standard deviations in trained subjects of about 1.5 dB. It appears that the dB SL MML and loudness estimates are not closely related.


1986 ◽  
Vol 51 (4) ◽  
pp. 362-369 ◽  
Author(s):  
Donna M. Risberg ◽  
Robyn M. Cox

A custom in-the-ear (ITE) hearing aid fitting was compared to two over-the-ear (OTE) hearing aid fittings for each of 9 subjects with mild to moderately severe hearing losses. Speech intelligibility via the three instruments was compared using the Speech Intelligibility Rating (SIR) test. The relationship between functional gain and coupler gain was compared for the ITE and the higher rated OTE instruments. The difference in input received at the microphone locations of the two types of hearing aids was measured for 10 different subjects and compared to the functional gain data. It was concluded that (a) for persons with mild to moderately severe hearing losses, appropriately adjusted custom ITE fittings typically yield speech intelligibility that is equal to the better OTE fitting identified in a comparative evaluation; and (b) gain prescriptions for ITE hearing aids should be adjusted to account for the high-frequency emphasis associated with in-the-concha microphone placement.


Crisis ◽  
2011 ◽  
Vol 32 (5) ◽  
pp. 246-253 ◽  
Author(s):  
Gretchen E. Ely ◽  
William R. Nugent ◽  
Julie Cerel ◽  
Mholi Vimbba

Background: The relationship between suicidal thinking and adolescent dating violence has not been previously explored in a sample of adolescent abortion patients. Aims: This paper highlights a study where the relationship between dating violence and severity of suicidal thinking was examined in a sample of 120 young women ages 14–21 seeking to terminate an unintended pregnancy. Methods: The Multidimensional Adolescent Assessment Scale and the Conflict in Adolescent Relationships Scale was used to gather information about psychosocial problems and dating violence so that the relationship between the two problems could be examined, while controlling for the other psychosocial problems. Results: The results suggest that dating violence was related to severity of suicidal thinking, and that the magnitude of this relationship was moderated by the severity of problems with aggression. Conclusions: Specifically, as the severity of participant’s general problems with aggression increased, the magnitude of the relationship between dating violence and severity of suicidal thinking increased. Limitations of the study and implications for practice are discussed.


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