1,921 research outputs found
Laterality of Eye Use by Bottlenose (Tursiops truncatus) and Rough-toothed (Steno bredanensis) Dolphins While Viewing Predictable and Unpredictable Stimuli
Laterality of eye use has been increasingly studied in cetaceans. Research supports that many cetacean species keep prey on the right side while feeding and preferentially view unfamiliar objects with the right eye. In contrast, the left eye has been used more by calves while in close proximity to their mothers. Despite some discrepancies across and within species, laterality of eye use generally indicates functional specialization of brain hemispheres in cetaceans. The present study aimed to examine laterality of eye use in bottlenose dolphins (Tursiops truncatus) and rough-toothed dolphins (Steno bredanensis) under managed care. Subjects were video-recorded through an underwater window while viewing two different stimuli, one predictable and static and the other unpredictable and moving. Bottlenose dolphins displayed an overall right-eye preference, especially while viewing the unpredictable, moving stimulus. Rough-toothed dolphins did not display eye preference while viewing stimuli. No significant correlations between degree of laterality and behavioral interest in the stimuli were found. Only for bottlenose dolphins were the degree of laterality and curiosity ratings correlated. This study extends research on cetacean lateralization to a species not extensively examined and to stimuli that varied in movement and degree of predictability. Further research is needed to make conclusions regarding lateralization in cetaceans
Alien Registration- Lilley, Willie B. (Saint Agatha, Aroostook County)
https://digitalmaine.com/alien_docs/33354/thumbnail.jp
The sign convention for quadrature Parkinson arrows in geomagnetic induction studies
Time series analysis, which is basic to modern geophysical data processing, involves a choice between working with a time dependence of e+iωt or e-iωt. In published work the choice made is sometimes not explicitly stated, leaving ambiguity in the interpretation of complex quantities with quadrature parts. Parkinson arrows are used in geomagnetic induction studies to summarize anomalous vertical magnetic fluctuations at different observing stations and to indicate regions of high electrical conductivity. Such arrows are now regularly computed as real and quadrature pairs. The general convention is often adopted of 'reversing' a calculated real arrow so that it will point toward a conductivity increase, but for quadrature arrows the practice between various published papers has generally not been so consistent. The present paper demonstrates that consistent practice for reversing or not reversing quadrature Parkinson arrows is possible when the initial convention for time dependence is taken into account. A reversal practice is determined for interpretation in terms of a simple channeling model. A related matter is the definition of phase. Phase values are also generally ambiguous unless the time dependence used (e-iωt or e+iωt) is stated
Deflected jet experiments in a turbulent combustor flowfield
Experiments were conducted to characterize the time-mean and turbulent flow field of a deflected turbulent jet in a confining cylindrical crossflow. Jet-to-crossflow velocity ratios of 2, 4, and 6 were investigated, under crossflow inlet swirler vane angles of 0 (swirler removed), 45 and 70 degrees. Smoke, neutrally buoyant helium-filled soap bubbles, and multi-spark flow visualization were employed to highlight interesting features of the deflected jet, as well as the tracjectory and spread pattern of the jet. A six-position single hot-wire technique was used to measure the velocities and turbulent stresses in nonswirling crossflow cases. In these cases, measurements confirmed that the deflected jet is symmetrical about the vertical plan passing through the crossflow axis, and the jet penetration was found to be reduced from that of comparable velocity ratio infinite crossflow cases. In the swirling crossflow cases, the flow visualization techniques enabled gross flow field characterization to be obtained for a range of lateral jet-to-crossflow velocity ratios and a range of inlet swirl strengths in the main flow
Experiments on opposed lateral jets injected into swirling crossflow
Experiments have been conducted to obtain the time-mean and turbulent quantities of opposed lateral jets in a low speed, nonreacting flowfield. A jet-to-crossflow velocity ratio of R = v sub J/u sub 0 = 4 was used throughout the experiments, with swirl vane angles of d = 0 (swirler removed), 45 and 70 deg used with the crossflow. Flow visualization techniques used were neutrally-buoyant helium-filled soap bubbles and multispark photography in order to obtain the gross flowfield characteristics. Measurements of time-mean and turbulent quantities were obtained utilizing a six-orientation single hot-wire technique. For the nonswirling case, the jets were found not to penetrate past the test-section centerline, in contrast to the single lateral jet with the same jet-to-crossflow velocity ratio. In the swirling cases, the crossflow remains in a narrow region near the wall of the test section. The opposed jets are swept from their vertical courses into spiral trajectories close to the confining walls. Extensive results are presented in r-x plane plots
Static noise tests on modified augmentor wing jet STOL research aircraft
Noise measurements were made to determine if recent modifications made to the bifurcated jetpipe to increase engine thrust had at the same time reduced the noise level. The noise field was measured by a 6-microphone array positioned on a 30.5m (100 ft) sideline between 90 and 150 degrees from the left engine inlet. Noise levels were recorded at three flap angles over a range of engine thrust settings from flight idle to emergency power and plotted in one-third octave band spectra. Little attenuation was observed at maximum power, but significant attenuation was achieved at approach and cruise power levels
Wrapping Transition and Wrapping-Mediated Interactions for Discrete Binding along an Elastic Filament: An Exact Solution
The wrapping equilibria of one and two adsorbing cylinders are studied along
a semi-flexible filament (polymer) due to the interplay between elastic
rigidity and short-range adhesive energy between the cylinder and the filament.
We show that statistical mechanics of the system can be solved exactly using a
path integral formalism which gives access to the full effect of thermal
fluctuations, going thus beyond the usual Gaussian approximations which take
into account only the contributions from the minimal energy configuration and
small fluctuations about this minimal energy solution. We obtain the free
energy of the wrapping-unwrapping transition of the filament around the
cylinders as well as the effective interaction between two wrapped cylinders
due to thermal fluctuations of the elastic filament. A change of entropy due to
wrapping of the filament around the adsorbing cylinders as they move closer
together is identified as an additional source of interactions between them.
Such entropic wrapping effects should be distinguished from the usual entropic
configuration effects in semi-flexible polymers. Our results may be applicable
to the problem of adsorption of proteins as well as synthetic nano-particles on
semi-flexible polymers such as DNA.Comment: 24 pages, 12 figure
4-Phosphothiophen-2-yl alanine: a new 5-membered analogue of phosphotyrosine
Polyclonal antibodies raised against 4-phosphothiophen-2-yl alanine 2a, a novel five-membered ring analogue of phosphotyrosine, showed high selectivity for phosphotyrosine and no cross-reactivity with other phosphorylated amino acids. Western blots showed that the polyclonal was similarly effective, but different in selectivity, to a commercially available monoclonal antibody
An increase in hookworm infection temporally associated with ecologic change.
This report describes a significant increase in the prevalence of hookworm infection in an area of Haiti where intestinal parasites are common, but hookworm has not been common. Changing environmental conditions, specifically deforestation and subsequent silting of a local river, have caused periodic flooding with deposition of a layer of sandy loam topsoil and increased soil moisture. We speculate that these conditions, conducive to transmission of the infection, have allowed hookworm to reemerge as an important human pathogen
Coupled currents in cosmic strings
We first examine the microstructure of a cosmic string endowed with two
simple Abelian currents. This microstructure depends on two state parameters.
We then provide the macroscopic description of such a string and show that it
depends on an additional Lorentz-invariant state parameter that relates the two
currents. We find that in most of the parameter space, the two-current string
is essentially equivalent to the single current-carrying string, i.e., only one
field condenses onto the defect. In the regions where two currents are present,
we find that as far as stability is concerned, one can approximate the dynamics
with good accuracy using an analytic model based on either a logarithmic (on
the electric side, i.e., for timelike currents) or a rational (on the magnetic
side, i.e., for spacelike currents) worldsheet Lagrangian.Comment: 25 pages, 9 figure
- …