scholarly journals Volitional Swimming Kinematics of Blacktip Sharks, Carcharhinus limbatus, in the Wild

Drones ◽  
2020 ◽  
Vol 4 (4) ◽  
pp. 78
Author(s):  
Marianne E. Porter ◽  
Braden T. Ruddy ◽  
Stephen M. Kajiura

Recent work showed that two species of hammerhead sharks operated as a double oscillating system, where frequency and amplitude differed in the anterior and posterior parts of the body. We hypothesized that a double oscillating system would be present in a large, volitionally swimming, conventionally shaped carcharhinid shark. Swimming kinematics analyses provide quantification to mechanistically examine swimming within and among species. Here, we quantify blacktip shark (Carcharhinus limbatus) volitional swimming kinematics under natural conditions to assess variation between anterior and posterior body regions and demonstrate the presence of a double oscillating system. We captured footage of 80 individual blacktips swimming in the wild using a DJI Phantom 4 Pro aerial drone. The widespread accessibility of aerial drone technology has allowed for greater observation of wild marine megafauna. We used Loggerpro motion tracking software to track five anatomical landmarks frame by frame to calculate tailbeat frequency, tailbeat amplitude, speed, and anterior/posterior variables: amplitude and frequency of the head and tail, and the body curvature measured as anterior and posterior flexion. We found significant increases in tailbeat frequency and amplitude with increasing swimming speed. Tailbeat frequency decreased and tailbeat amplitude increased as posterior flexion amplitude increased. We found significant differences between anterior and posterior amplitudes and frequencies, suggesting a double oscillating modality of wave propagation. These data support previous work that hypothesized the importance of a double oscillating system for increased sensory perception. These methods demonstrate the utility of quantifying swimming kinematics of wild animals through direct observation, with the potential to apply a biomechanical perspective to movement ecology paradigms.

2014 ◽  
Vol 54 (9) ◽  
pp. 1476 ◽  
Author(s):  
N. Y. Kim ◽  
S. J. Kim ◽  
J. H. Park ◽  
M. R. Oh ◽  
S. Y. Jang ◽  
...  

The present study aimed to gather basic information on measuring body surface temperature (BST) of cattle by using infrared thermography (IRT) and find out whether BST measurement is a useful method to detect thermal balance of livestock. Twenty-seven Hanwoo steers were examined in a field trial. The BST of five body regions (eye, nose, horn, ear, rear) was measured five times daily, with three replicates, during 3 days each season. Body surface temperature of cattle is directly affected by ambient temperature and humidity, and showed different ranges for each region. The BSTs of nose, horns and ears were significantly (P < 0.05) lower than those of eyes and rear area. Rear-area BST was significantly lower than eye-area BST when the ambient temperature was low (P < 0.05). Eye BST (EBST) was highest (P < 0.05) and the least variable of all BSTs measured. Therefore, the eye area of cattle was the most thermostable part of the body. There were significant (P < 0.05) differences among seasonal EBSTs of steers. The EBST range was highest in the summer (37.9–42.2°C), followed by autumn (34.3–37.4°C), spring (33.8–36.5°C) and winter (29.8–32.6°C). During extreme cold, EBST showed a large standard deviation. During conditions of extreme heat, EBST was above the average body temperature of cattle. The results of the present study indicated that BST well reflects the thermal circumstances surrounding animals and may be used as one of the effective tools for precision cattle farming.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tali Leibovich-Raveh ◽  
Ashael Raveh ◽  
Dana Vilker ◽  
Shai Gabay

AbstractWe make magnitude-related decisions every day, for example, to choose the shortest queue at the grocery store. When making such decisions, which magnitudes do we consider? The dominant theory suggests that our focus is on numerical quantity, i.e., the number of items in a set. This theory leads to quantity-focused research suggesting that discriminating quantities is automatic, innate, and is the basis for mathematical abilities in humans. Another theory suggests, instead, that non-numerical magnitudes, such as the total area of the compared items, are usually what humans rely on, and numerical quantity is used only when required. Since wild animals must make quick magnitude-related decisions to eat, seek shelter, survive, and procreate, studying which magnitudes animals spontaneously use in magnitude-related decisions is a good way to study the relative primacy of numerical quantity versus non-numerical magnitudes. We asked whether, in an animal model, the influence of non-numerical magnitudes on performance in a spontaneous magnitude comparison task is modulated by the number of non-numerical magnitudes that positively correlate with numerical quantity. Our animal model was the Archerfish, a fish that, in the wild, hunts insects by shooting a jet of water at them. These fish were trained to shoot water at artificial targets presented on a computer screen above the water tank. We tested the Archerfish's performance in spontaneous, untrained two-choice magnitude decisions. We found that the fish tended to select the group containing larger non-numerical magnitudes and smaller quantities of dots. The fish selected the group containing more dots mostly when the quantity of the dots was positively correlated with all five different non-numerical magnitudes. The current study adds to the body of studies providing direct evidence that in some cases animals’ magnitude-related decisions are more affected by non-numerical magnitudes than by numerical quantity, putting doubt on the claims that numerical quantity perception is the most basic building block of mathematical abilities.


Development ◽  
1992 ◽  
Vol 115 (1) ◽  
pp. 319-335 ◽  
Author(s):  
M. Jerka-Dziadosz ◽  
N. Garreau de Loubresse ◽  
J. Beisson

kin241 is a monogenic nuclear recessive mutation producing highly pleiotropic effects on cell size and shape, generation time, thermosensitivity, nuclear reorganization and cortical organization. We have analyzed the nature of the cortical disorders and their development during division, using various specific antibodies labelling either one of the cortical cytoskeleton components, as was previously done for analysis of cortical pattern formation in the wild type. Several abnormalities in basal body properties were consistently observed, although with a variable frequency: extra microtubules in either the triplets or in the lumen; nucleation of a second kinetodesmal fiber; abnormal orientation of the newly formed basal body with respect to the mother one. The latter effect seems to account for the major observed cortical disorders (reversal, intercalation of supplementary ciliary rows). The second major effect of the mutation concerns the spatiotemporal map of cortical reorganization during division. Excess basal body proliferation occurs and is correlated with modified boundaries of some of the cortical domains identified in the wild type on the basis of their basal body duplication pattern. This is the first mutant described in a ciliate in which both the structure and duplication of basal bodies and the body plan are affected. The data support the conclusion that the mutation does not alter the nature of the morphogenetic signal(s) which pervade the dividing cell, nor the competence of cytoskeletal structures to respond to signalling, but affects the local interpretation of the signals.


2018 ◽  
Vol 4 (12) ◽  
pp. eaau6252 ◽  
Author(s):  
Yao Guo ◽  
Weixuan Zhang ◽  
Hanchun Wu ◽  
Junfeng Han ◽  
Yongliang Zhang ◽  
...  

The edges of layered materials have unique properties that substantially differ from the body regions. In this work, we perform a systematic Raman study of the edges of various layered materials (MoS2, WS2, WSe2, PtS2, and black phosphorus). The Raman spectra of the edges feature newly observed forbidden Raman modes, which are originally undetectable from the body region. By selecting the edge type and the polarization directions of the incident and scattered light, all forbidden Raman modes are distinctly detected. Optical simulations show that the edges of layered materials drastically distort the electromagnetic fields of both the incident and scattered light, so that the light interacts with the edges in a distinct way, which differs from its interactions with the body regions.


Author(s):  
Ana L. Ibáñez ◽  
Diana Y. Montero

This study documents the presence of crypsis in Mugil curema juveniles under laboratory culture. Initially, the juveniles were located in one brown tank (BT1), later almost half of the individuals were placed in a white tank (WT) where they showed a pigmentation change to white. After being moved to another brown tank (BT2), the juveniles changed to their brown original colour, but kept a few small white spots on the dorsal axis of the body. The ventral head melanophore pattern also changed in the white specimens. Temperature (°C), oxygen (mg l−1) and Illuminance light (Lux m−2), total length (mm) and total weight (g) were determined by tank. Chromaticity was measured in L*(relative luminance) a*(measurement relating to the redness or greenness of the light) b*(measurement relating to the yellowness or blueness of the light) coordinates where all three values are required to completely describe an object’s colour. One-way ANOVA showed no differences for temperature, oxygen and illuminance light among tanks. Length and weight were similar for BT1 and WT but both were different from BT2. The white juveniles depicted similar L* as the WT background as well as the dorsal area of the brown pigmentation and converted juveniles to the brown tanks BT1 and BT2, respectively. Therefore, the fish's body relative luminance matches the background. To our knowledge this behaviour has not been reported before for any fish mullet either cultured or living in the wild.


2021 ◽  
Author(s):  
Masumeh Delgarmi ◽  
Hamed Heravi ◽  
Ali Rahimpour Jounghani ◽  
Abdullah Shahrezie ◽  
Afshin Ebrahimi ◽  
...  

AbstractStudying human postural structure is one of the challenging issues among scholars and physicians. The spine is known as the central axis of the body, and due to various genetic and environmental reasons, it could suffer from deformities that cause physical dysfunction and correspondingly reduce people’s quality of life. Radiography is the most common method for detecting these deformities and requires monitoring and follow-up until full treatment; however, it frequently exposes the patient to X-rays and ionization and as a result, cancer risk is increased in the patient and could be highly dangerous for children or pregnant women. To prevent this, several solutions have been proposed using topographic data analysis of the human back surface. The purpose of this research is to provide an entirely safe and non-invasive method to examine the spiral structure and its deformities. Hence, it is attempted to find the exact location of anatomical landmarks on the human back surface, which provides useful and practical information about the status of the human postural structure to the physician.In this study, using Microsoft Kinect sensor, the depth images from the human back surface of 105 people were recorded and, our proposed approach - Deep convolution neural network-was used as a model to estimate the location of anatomical landmarks. In network architecture, two learning processes, including landmark position and affinity between the two associated landmarks, are successively performed in two separate branches. This is a bottom-up approach; thus, the runtime complexity is considerably reduced, and then the resulting anatomical points are evaluated concerning manual landmarks marked by the operator as the benchmark. Our results showed that 86.9% of PDJ and 80% of PCK. According to the results, this study was more effective than other methods with more than thousands of training data.


Author(s):  
Fangfang Liu ◽  
Mingqi Shen ◽  
Taosheng Li ◽  
Chunyu Liu

In order to calculate the dose conversion coefficients for proton, the voxel model of Chinese Reference Adult Woman (CRAW) was established by the Monte Carlo transport code FLUKA according to the Chinese reference data and the Asian reference data. Compared with the reference data, the deviations of the mass for organs or tissues of CRAW is less than ±5%. Calculations have been performed for 14 incident monoenergetic protons energies from 0.02GeV to 10TeV at the irradiation incident of anterior-posterior (AP) and posterior-anterior (PA). The results of fluence-to-effective dose conversion coefficients are compared with data from the different models such as an anthropomorphic mathematical model, ICRP reference adult voxel model, the voxel-based visible Chinese human (VCH). Anatomical differences among various computational phantoms and the spatial geometric positions of the organs or tissues lead to the discrepancies of the effective dose conversion coefficients in the ranging from a negligible level to 107% at proton energies below 0.2GeV. The deviations of the coefficients, above 0.2GeV, are mostly within 10%. The results of fluence-to-organ absorbed dose conversion coefficients are compared with the data of VCH. The deviations of the coefficients, below and above 0.2GeV, are within 150% and 20%, respectively. The primary factors of the deviations for the coefficients should be due to the differences of the organ mass and the size of the body shape.


2018 ◽  
Vol 198 ◽  
pp. 04010
Author(s):  
Zhonghao Han ◽  
Lei Hu ◽  
Na Guo ◽  
Biao Yang ◽  
Hongsheng Liu ◽  
...  

As a newly emerging human-computer interaction, motion tracking technology offers a way to extract human motion data. This paper presents a series of techniques to improve the flexibility of the motion tracking system based on the inertial measurement units (IMUs). First, we built a most miniatured wireless tracking node by integrating an IMU, a Wi-Fi module and a power supply. Then, the data transfer rate was optimized using an asynchronous query method. Finally, to simplify the setup and make the interchangeability of all nodes possible, we designed a calibration procedure and trained a support vector machine (SVM) model to determine the binding relation between the body segments and the tracking nodes after setup. The evaluations of the whole system justify the effectiveness of proposed methods and demonstrate its advantages compared to other commercial motion tracking system.


1979 ◽  
Vol 82 (1) ◽  
pp. 273-280
Author(s):  
B. S. WONG ◽  
DONALD M. MILLER ◽  
T. T. DUNAGAN

Body wall muscles of an acanthocephalan Macracanthorhynchus hirudinaceus were studied by means of scanning and light microscopy and intracellular recording of potentials. Three types of spontaneous potential changes were found: larger (L) potentials which usually exhibited overshoot and were as large as 65 mV; smaller symmetric (A) potentials approximately 15 mV in amplitude; and even smaller asymmetric (S) potentials which sometimes reached 10 mV. The potentials recorded depended upon the position of the electrode in the anterior-posterior, as well as the medialateral, axis. Tetrodotoxin eliminated L but not S potentials. Ouabain lengthened the time for depolarization of L potentials and depolarized the membrane potentials. It is suggested that the rete system activates the body wall muscles in Acanthocephala.


2021 ◽  
pp. 31-32
Author(s):  
Sahil Gandhi ◽  
Asit Natekar

Main function of scrotum is to hold testes at optimal temperature for spermatogenesis. Sperm production in the testes is a temperature sensitive process. It requires an environment that is 2 to 6°C cooler than the body core. The temperature of the testes is regulated by the scrotal wall. Tunica dartos muscle changes the surface area of the scrotal skin by contracting or relaxing depending on the ambient temperature. This study postulates that if the thickness or the tone of this muscle is more thereby contributing to scrotal wall thickening, it will hamper the thermoregulation and spermatogenesis leading to poor sperm production. This could be an besides varicocoele another cause of male infertility which has been an established cause. This study will help to suspect the patients of infertility caused by thick scrotal wall. This study is aimed to study scrotal wall thickness and with the help of Ultrasonography. to establish norms The study was conducted at department of Radio-diagnosis at the tertiary care hospital, Sangli. The study started after approval of institutional ethical committee. This is a cross sectional observational study for the duration of 4 months. Total number of 50 cases was achieved in this time duration which satised the inclusion criteria. Statistical method used was Student's T test. Scrotal ultrasonography was performed using linear and curvilinear probe with sta (5-12 MHz) (2-5 MHz) on Philips Afniti50, after ndoff pad allowing some time for the dartos muscle to relax and scrotal wall thickness is measured on either side on three surfaces (anterior, posterior and lateral) and means were obtained. This study found that there was no difference between anterior, posterior, lateral wall thicknesses on ipsilateral side or contralateral side. There is no need to take three different wall thicknesses and convenience and suitability of any scrotal wall thickness would be equally effective.


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