scholarly journals Can hook-bending be let off the hook? Bending/unbending of pliant tools by cockatoos

2017 ◽  
Vol 284 (1862) ◽  
pp. 20171026 ◽  
Author(s):  
I. B. Laumer ◽  
T. Bugnyar ◽  
S. A. Reber ◽  
A. M. I. Auersperg
Keyword(s):  
Cognitive Processing ◽  
Tool Use ◽  
Vertical Tube ◽  
Nest Building ◽  
Straight Wire ◽  
Horizontal Tubes ◽  
Set Up ◽  
Vertical Tubes ◽  
Similar Task ◽  
A Current

The spontaneous crafting of hook-tools from bendable material to lift a basket out of a vertical tube in corvids has widely been used as one of the prime examples of animal tool innovation. However, it was recently suggested that the animals' solution was hardly innovative but strongly influenced by predispositions from habitual tool use and nest building. We tested Goffin's cockatoo, which is neither a specialized tool user nor a nest builder, on a similar task set-up. Three birds individually learned to bend hook tools from straight wire to retrieve food from vertical tubes and four subjects unbent wire to retrieve food from horizontal tubes. Pre-experience with ready-made hooks had some effect but was not necessary for success. Our results indicate that the ability to represent and manufacture tools according to a current need does not require genetically hardwired behavioural routines, but can indeed arise innovatively from domain general cognitive processing.

Conditions for a Pipe to Run Full When Discharging Liquid Into a Space Filled With Gas

1977 ◽  
Vol 99 (2) ◽  
pp. 405-413 ◽  
Author(s):  
G. B. Wallis ◽  
C. J. Crowley ◽  
Y. Hagi
Keyword(s):  
Flow Regime ◽  
Slug Flow ◽  
Flow Patterns ◽  
Vertical Tube ◽  
Diameter Ratio ◽  
Phase Flow ◽  
Two Phase ◽  
Horizontal Tubes ◽  
Variable Space ◽  
Vertical Tubes

Experiments were performed with water discharging into air from horizontal and vertical tubes of several diameters. The horizontal tubes discharged into a variable space between vertical plates. The effects of length/diameter ratio and the shape of the end of the tube were investigated for the case of vertical tubes. In each case the conditions for the pipes to run full were associated with the formation and washout of large gas bubbles resembling those occurring in the slug flow regime of two-phase flow. The data for horizontal tubes were successfully correlated with some simple limiting theories and dimensionless representations. The vertical tube results were influenced by stability phenomena and nonsymmetrical flow patterns; as a result only a partial understanding was obtained.

Transient rheological behavior of blood in low-shear tube flow: velocity profiles and effective viscosity

1995 ◽  
Vol 268 (1) ◽  
pp. H25-H32 ◽  
Author(s):  
C. Alonso ◽  
A. R. Pries ◽  
O. Kiesslich ◽  
D. Lerche ◽  
P. Gaehtgens
Keyword(s):  
Effective Viscosity ◽  
Velocity Profiles ◽  
Low Flow ◽  
Cross Sectional ◽  
Video Recordings ◽  
Horizontal Tubes ◽  
Rbc Aggregation ◽  
Glass Tubes ◽  
Vertical Tubes ◽  
Low Shear

Velocity profiles of human blood flowing through vertical and horizontal glass tubes (25–100 microns ID) were measured as a function of time following a sudden reduction of wall shear stress (tau w) from a high value to values ranging from 2 to 100 mPa. Cell velocities at various radial positions were determined off-line from video recordings by digital image analysis. In vertical tubes, symmetric velocity profiles were obtained that developed increasing bluntness with time, particularly at lower tau w and in smaller tubes. In horizontal tubes, velocity profiles developed strong asymmetry as a function of time. Red blood cell (RBC) sedimentation was associated with uniform low flow velocities in the concentrating cell sediment, whereas faster flow and almost parabolic profiles were observed in the supernatant plasma region. Calculations of effective blood viscosity showed a decrease with time at low tau w in vertical tubes but an increase in horizontal tubes. The differences between profile shape and effective viscosity in vertical and horizontal tubes disappeared at tau w > 50 mPa. These findings are related to the cross-sectional distribution of RBC, which depends on RBC aggregation and sedimentation.

XXXVIII.—Observations with a Current Meter in Loch Ness

1909 ◽  
Vol 29 ◽  
pp. 619-647 ◽  
Author(s):  
E. M. Wedderburn ◽  
W. Watson
Keyword(s):  
Experimental Investigation ◽  
Fixed Point ◽  
Great Lakes ◽  
Large Lake ◽  
Deep Lakes ◽  
Small Lake ◽  
Stormy Weather ◽  
Set Up ◽  
A Current ◽  
Made In

One of the authors having made an experimental investigation on the currents produced in a trough of water by a blast of air driven along the surface of the water, it was desired to test the correctness of his deductions by actual observations in a large lake. Loch Ness was chosen on account of its length and uniformity of basin, as it was thought that the length and narrowness of the loch would lead to clearly defined currents being set up in the lake. The sequel showed, as in the case of observations on seiches, that it would have been better to confine attention to a smaller lake, for a twofold reason, (1) because in a large lake the difficulties of observations are much greater than in a small lake during stormy weather, and in very deep lakes the difficulties in the way of obtaining a fixed point from which to use the current meter are formidable, and (2) because it would seem from a few observations made in Loch Garry (Ness Basin) that currents are more defined and more regular in small than in great lakes.

An Analytical Study of Laminar Film Condensation: Part 2—Single and Multiple Horizontal Tubes

1961 ◽  
Vol 83 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Michael Ming Chen
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Horizontal Tube ◽  
Vertical Tube ◽  
Film Condensation ◽  
Transfer Coefficients ◽  
Inertia Effects ◽  
Horizontal Tubes ◽  
Laminar Film ◽  
Laminar Film Condensation

The boundary-layer equations for laminar film condensation are solved for (a) a single horizontal tube, and (b) a vertical bank of horizontal tubes. For the single-tube case, the inertia effects are included and the vapor is assumed to be stationary outside the vapor boundary layer. Velocity and temperature profiles are obtained for the case μvρv/μρ ≪ 1 and similarity is found to exist exactly near the top stagnation point, and approximately for the most part of the tube. Heat-transfer results computed with these similar profiles are presented and discussed. For the multiple-tube case, the analysis includes the effect of condensation between tubes, which is shown to be partly responsible for the high observed heat-transfer rate for vertical tube banks. The inertia effects are neglected due to the insufficiency of boundary-layer theory in this case. Heat-transfer coefficients are presented and compared with experiments. The theoretical results for both cases are also presented in approximate formulas for ease of application.

Slow Wave Sleep During a Brief Nap is Related to Reduced Cognitive Deficits During Sleep Deprivation

SLEEP ◽  
2021 ◽  
Author(s):  
Michelle E Stepan ◽  
Erik M Altmann ◽  
Kimberly M Fenn
Keyword(s):  
Sleep Deprivation ◽  
Cognitive Processing ◽  
Slow Wave ◽  
Slow Wave Sleep ◽  
Vigilance Task ◽  
Attention Task ◽  
Performance Deficits ◽  
Impaired Performance ◽  
Short Period ◽  
Set Up

Abstract Sleeping for a short period (i.e., napping) may help mitigate impairments in cognitive processing caused by sleep deprivation, but there is limited research on effects of brief naps in particular. Here, we tested the effect of a brief nap opportunity (30- or 60-min) during a period of sleep deprivation on two cognitive processes with broad scope, placekeeping and vigilant attention. In the evening, participants (N = 280) completed a placekeeping task (UNRAVEL) and a vigilant attention task (Psychomotor Vigilance Task [PVT]) and were randomly assigned to either stay awake overnight or sleep at home. Sleep-deprived participants were randomly assigned to receive either no nap opportunity, a 30-min opportunity, or a 60-min opportunity. Participants who napped were set up with polysomnography. The next morning, sleep participants returned, and all participants completed UNRAVEL and the PVT. Sleep deprivation impaired performance on both tasks, but nap opportunity did not reduce the impairment, suggesting that naps longer than those tested may be necessary to cause group differences. However, in participants who napped, more time spent in slow-wave sleep (SWS) was associated with reduced performance deficits on both tasks, effects we interpret in terms of the role of SWS in alleviating sleep pressure and facilitating memory consolidation.

scholarly journals Sex Bias and Social Influences on Savanna Chimpanzee (Pan troglodytes verus) Nest Building Behavior

2020 ◽  
Vol 41 (6) ◽  
pp. 849-869 ◽  
Author(s):  
Fiona A. Stewart ◽  
Jill D. Pruetz
Keyword(s):  
Sex Differences ◽  
Pan Troglodytes ◽  
Tool Use ◽  
Great Apes ◽  
Nest Building ◽  
Pan Troglodytes Verus ◽  
Adult Males ◽  
Extractive Foraging ◽  
Individual Level ◽  
Adult Females

AbstractMany primates show sex differences in behavior, particularly social behavior, but also tool use for extractive foraging. All great apes learn to build a supportive structure for sleep. Whether sex differences exist in building, as in extractive foraging, is unknown, and little is known about how building skills develop and vary between individuals in the wild. We therefore aimed to describe the nesting behavior of savanna chimpanzees (Pan troglodytes verus) in Fongoli, Senegal to provide comparative data and to investigate possible sex or age differences in nest building behaviors and nest characteristics. We followed chimpanzee groups to their night nesting sites to record group (55 nights) and individual level data (17 individuals) on nest building initiation and duration (57 nests) during the dry season between October 2007 and March 2008. We returned the following morning to record nest and tree characteristics (71 nests built by 25 individuals). Fongoli chimpanzees nested later than reported for other great apes, but no sex differences in initiating building emerged. Observations were limited but suggest adult females and immature males to nest higher, in larger trees than adult males, and adult females to take longer to build than either adult or immature males. Smaller females and immature males may avoid predation or access thinner, malleable branches, by nesting higher than adult males. These differences suggest that sex differences described for chimpanzee tool use may extend to nest building, with females investing more time and effort in constructing a safe, warm structure for sleep than males do.

Empirical Correlation of Factors Influencing Departure From Nucleate Boiling in Steam-Water Mixtures Flowing in Vertical Round Tubes

1966 ◽  
Vol 88 (4) ◽  
pp. 367-373 ◽  
Author(s):  
D. Pasint ◽  
R. H. Pai
Keyword(s):  
Experimental Data ◽  
Heat Flux ◽  
Forced Convection ◽  
Mass Flow ◽  
Nucleate Boiling ◽  
Vertical Tube ◽  
Empirical Correlation ◽  
Factors Influencing ◽  
Vertical Tubes ◽  
Heated Length

An empirical correlation of forced convection DNB for steam-water mixtures between 500 and 3000 psia in uniformly heated vertical tubes is proposed. DNB quality is expressed in terms of pressure, mass flow, inlet enthalpy, heated length from inlet to DNB point, and tube dia. The experimental data of the authors at 2000–3000 psia, 250,000–1,000,000 lb/hr sq ft2 mass flow, and 40,000–180,000 Btu/hr sq ft heat flux, obtained from a 6 ft long, 3/4-in-ID electrically heated vertical tube, are correlated with other published results ranging from 500 to 2000 psia.

scholarly journals IX. On a new form of voltaic battery

1884 ◽  
Vol 37 (232-234) ◽  
pp. 141-142
Keyword(s):  
Internal Resistance ◽  
Positive Element ◽  
Negative Element ◽  
Sodium Batteries ◽  
New Form ◽  
Set Up ◽  
The Cost ◽  
To Receive ◽  
Soda Solution ◽  
A Current

The battery which I have the honour to bring under the notice of the Royal Society is one of high electromotive force, namely, about two and three quarter volts, and a single cell consequently decomposes water; it is very light and portable, and convenient for many purposes. The electro-positive element is sodium, the electro-negative element is either carbon, spongy platinum,copper, or other metallic gauze; no fluid is used in which to immerse the plates, but the atmospheric air which is always impregnated with more or less hygrometric moisture serves to set up the action of the battery by giving up sufficient moisture to wet the surface of the sodium, so that a very thin film of fluid (a solution of soda), is thus interposed between the sodium and electro-negative element, and the internal resistance is very small in consequence of the thinness of the film of fluid. The sodium is used in the form of plates, conveniently about a quarter of an inch thick, and the plates of carbon, of which one is placed on each side of the sodium, a little longer and about the same thickness as the sodium; these plates, carbon, sodium, carbon, are kept together by means of vulcanised rubber bands, and suspended vertically, a vessel being placed underneath to receive the soda solution as it forms. A battery composed of plates 10 inches long and ½ an inch wide gives a current of 0·122 ampére at first starting, but as polarisation takes place, after five minutes, only 0·079 ampère. The cost of a battery of this size is 0·40 fr. (4 d . about), it remains in action for six days without the renewal of the sodium. Batteries of larger dimensions, as for example 10 inches long and 15/8 inches wide, last four weeks, because the action is chiefly on the edges of the sodium plate, and the broader the plate the longer the sodium lasts without renewal.

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