scholarly journals A DIRECT LIGHT EFFECT ON MAINTAINING PHOTOSYNTHETIC ACTIVITY OF NITELLA CHLOROPLASTS

1970 ◽  
Vol 44 (2) ◽  
pp. 305-309 ◽  
Author(s):  
I. W. Craig ◽  
A. Gibor
Keyword(s):  
Direct Effect ◽  
Photosynthetic Activity ◽  
Continuous Light ◽  
Longitudinal Axis ◽  
The Other ◽  
Light Effect ◽  
Direct Light ◽  
Stationary Layer ◽  
14Co2 Atmosphere ◽  
Effect Of Light

The chloroplasts of internodal cells of Nitella are fixed to a stationary layer of cytoplasm whereas the nuclei and most of the cytoplasm stream along the longitudinal axis. Isolated internodal cells were maintained for several days with half the cell kept in the dark, the other half kept under continuous light. Photosynthetic activity of the cells was checked by placing the cell evenly illuminated in a 14CO2 atmosphere. Chloroplasts of the previously dark half of the cell were found to fix only half as much CO2 as the chloroplasts which were continuously illuminated. These results are discussed in relation to the possible direct effect of light on biosynthetic reactions of mature chloroplasts.

scholarly journals Seat pitch and comfort of a staggered seat configuration

Work ◽  
2021 ◽  
Vol 68 (s1) ◽  
pp. S151-S159
Author(s):  
Zhihui Liu ◽  
T. Rotte ◽  
S. Anjani ◽  
P. Vink
Keyword(s):  
Longitudinal Axis ◽  
The Other ◽  
Sitting Position ◽  
Lateral Direction ◽  
Top View ◽  
Design Freedom ◽  
Cabin Interior ◽  
Physical Dimensions

BACKGROUND: Staggered seats are a solution for the Flying-V aircraft, where the cabin’s longitudinal axis has a 26 degrees angle with respect to the direction of flight, to compensate for an otherwise oblique sitting position. However, little is known on acceptable pitches in this staggered configuration. OBJECTIVE: The goal of this research is to evaluate the comfort of different pitches for seats that are staggered relative to the cabin’s longitudinal axis. METHODS: Two rows of staggered seats are positioned at three different pitches (27, 29 and 31 inches). 53 participants were seated in each setup. For each, a questionnaire was completed including questions on comfort and discomfort, top view photos were taken to analyse postures and physical dimensions were recorded to define passengers’ space. RESULTS: Comfort as well as discomfort were significantly different for the three setups. The comfort at 27 inches was seen as unacceptably low. The 29 and 31-inch configurations showed to result in acceptable levels of comfort, comparable to higher-end seating layouts. There were very little complaints about space in lateral direction (elbow and seat width), showing the advantage of having your won armrest and shoulder space in the staggered configuration. Interesting was that at larger pitches more complaints were found for the seat characteristics, probably in the shorter pitch the other discomfort was overruling this. CONCLUSION: The 26-degree staggered configuration offers improvements in shoulder- and elbow-space. The results for the 29- and 31-inch are expected to allow enough design freedom for further exploration of such a configuration for the Flying-V cabin interior.

INTERACTIONS OF THE PINEAL AND EXPOSURE TO CONTINUOUS LIGHT ON ORGAN WEIGHTS OF FEMALE RATS

1961 ◽  
Vol 36 (4) ◽  
pp. 617-624 ◽  
Author(s):  
Richard Jay Wurtman ◽  
Willard Roth ◽  
Mark D. Altschule ◽  
Judith J. Wurtman
Keyword(s):  
Light Exposure ◽  
Continuous Light ◽  
Female Rats ◽  
Constant Light ◽  
Ovarian Weight ◽  
Organ Weights ◽  
Bovine Pineal Extracts ◽  
Pineal Extracts ◽  
Effect Of Light

ABSTRACT Either exposure to constant light for 80 days or pinealectomy produced similar changes in the weights of the ovaries and adrenals of female rats. These were not additive when both procedures were employed. Pinealectomy did not share with light-exposure the capacity to induce uterine hypertrophy. Rats exposed to constant light for 56 days had lighter pineals than animals kept in darkness; this decrease was not affected by administration of bovine pineal extracts. The increase in ovarian weight produced in rats by exposure to light for 56 days was prevented by bovine pineal extracts, but these extracts were without effect on the uterine hypertrophy produced under the same conditions. These data suggest that the effect of light upon the weight of the ovary is mediated via the pineal.

EFFECT OF LIGHT SOURCE DISTANCE ON THE DISCRIMINATION AND GLOSS PERCEPTION OF PAPER

2021 ◽  
Author(s):  
X.Y. Zhu ◽  
S. Inoue ◽  
H. Sato ◽  
Y. Mizokami
Keyword(s):  
Light Source ◽  
Specular Reflection ◽  
The Other ◽  
Visual Property ◽  
Source Distance ◽  
Effect Of Light

Gloss is an essential visual property of objects. It is still controversial how well gloss constancy works under different light distributions. In this paper, we conducted three experiments of different light distributions to investigate whether the stable discrimination and gloss constancy of paper occurred with different glossiness levels at the different light source distances and illuminances. The results suggest instability of paper discrimination and gloss perception when both light source distance and illuminance change. Then we tested two additional conditions. One is setting the distance the same and manipulating the illumination. The other is setting the illuminance constant and manipulating the distance, respectively. We further verify that illuminance and specular reflection can affect material and gloss perception, regardless of the width of the highlight region changed by light source distance.

Coordinated righting behaviour in locusts

2001 ◽  
Vol 204 (4) ◽  
pp. 637-648 ◽  
Author(s):  
A.A. Faisal ◽  
T. Matheson
Keyword(s):  
Driving Force ◽  
Flat Surface ◽  
Longitudinal Axis ◽  
Upright Position ◽  
The Body ◽  
The Other ◽  
Legged Robots ◽  
Naturally Occurring ◽  
Key Features ◽  
Low Levels

A locust placed upside down on a flat surface uses a predictable sequence of leg movements to right itself. To analyse this behaviour, we made use of a naturally occurring state of quiescence (thanatosis) to position locusts in a standardised upside-down position from which they spontaneously right themselves. Locusts grasped around the pronotum enter a state of thanatosis during which the limbs can be manipulated into particular postures, where they remain, and the animal can be placed upside down on the ground. When released, thanatosis lasts 4–456 s (mean 73 s) before the animal suddenly becomes active again and rights itself within a further 600 ms. Thanatosis is characterised by very low levels of leg motor activity. During righting, one hind leg provides most of the downward force against the ground that rolls the body around a longitudinal axis towards the other side. The driving force is produced by femoral levation (relative to the body) at the trochanter and by tibial extension. As the animal rolls over, the hind leg on the other side is also levated at the trochanter, so that it does not obstruct the movement. The forelegs and middle legs are not required for successful righting but they can help initially to tip the locust to one side, and at the end of the movement they help stop the roll as the animal turns upright. Individual locusts have a preferred righting direction but can, nevertheless, roll to either side. Locusts falling upside down through the air use both passive and active mechanisms to right themselves before they land. Without active movements, falling locusts tend to rotate into an upright position, but most locusts extend their hind leg tibiae and/or spread their wings, which increases the success of mid-air righting from 28 to 49 % when falling from 30 cm. The rapid and reliable righting behaviour of locusts reduces the time spent in a vulnerable upside-down position. Their narrow body geometry, large hind legs, which can generate substantial dorsally directed force, and the particular patterns of coordinated movements of the legs on both sides of the body are the key features that permit locusts to right themselves effectively. The reliability of autonomous multi-legged robots may be enhanced by incorporating these features into their design.

WATER FLOWS AROUND THE COMB PLATES OF THE CTENOPHORE PLEUROBRACHIA PLOTTED BY COMPUTER: A MODEL SYSTEM FOR STUDYING PROPULSION BY ANTIPLECTIC METACHRONISM

1993 ◽  
Vol 177 (1) ◽  
pp. 113-128 ◽  
Author(s):  
D. Barlow ◽  
M. A. Sleigh ◽  
R. J. White
Keyword(s):  
Computer Program ◽  
Water Flow ◽  
High Speed ◽  
Beat Frequency ◽  
Longitudinal Axis ◽  
Model System ◽  
The Other ◽  
Contour Maps ◽  
Water Flows ◽  
Pleurobrachia Pileus

Patterns of water flow around steadily beating comb plates of Pleurobrachia pileus were tracked using suspended plastic beads. The positions of the beads and the comb plates in the plane of the central longitudinal axis of the comb row were digitised from high-speed cine films covering several beat cycles. All of the data from each sequence were combined using a computer program which integrated them into a standard cycle, and the resulting data were plotted by a second computer program to produce charts for different stages in the beat cycle showing the flow velocity at a grid of points. On these charts, contour maps were drawn to indicate the speed and direction of the water flow. Water is drawn towards each comb row from ahead and from the sides and accelerates strongly backwards in a fairly narrow stream which joins those from the other seven comb rows at the rear of the animal. At a beat frequency of 10 Hz the comb plates move with a tip speed of up to 70 mm s-1 in their effective stroke; they have an estimated Reynolds number of 9 in this stroke. Changes in inter- plate volume between adjacent antiplectically coordinated plates are very important in propulsion, particularly near the end of the effective stroke when pairs of adjacent plates close together and cause the high-speed water from around the ciliary tips to be shed into the overlying stream as a series of jets at speeds of 50 mm s-1 or more. The antiplectic coordination of the comb plates makes a major contribution to the efficiency of propulsion.

scholarly journals Effect of Light Quality and Microbiological Inoculum on Geranium (Pelargonium zonale L.) Gas Exchange Parameters

2016 ◽  
Vol 44 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Anita Barbara SCHROETER-ZAKRZEWSKA ◽  
Klaudia BOROWIAK ◽  
Agnieszka WOLNA-MARUWKA
Keyword(s):  
Blue Light ◽  
Transpiration Rate ◽  
Light Quality ◽  
Photosynthetic Activity ◽  
Intercellular Co2 Concentration ◽  
Fluorescent Light ◽  
Gas Exchange Parameters ◽  
Pelargonium Zonale ◽  
Effective Microorganisms ◽  
Effect Of Light

Geranium plants were cultivated in a growth chamber with different light quality and microorganism inoculation conditions. The long-term effect of irradiance quality (LED and fluorescent) as well as two types of microorganism treatments on photosynthetic activity parameters was examined. The maximum reached values of net photosynthesis rate (PN), stomatal conductance (gs), transpiration rate (E) and intercellular CO2 concentration (Ci) were afterwards measured in plants cultivated under six colours of light – white, white-blue, blue, red, red-blue and green – emitted by two types of lamp: LED and fluorescent. Two types of microorganism treatments were used: BAF1 created in the Department of General and Environmental Microbiology and the commonly used Effective Microorganisms (EM) biopreparation. A highest level of PN were found in plants after cultivation under white-blue light (both – fluorescent and LED) and treated by BAF1. The positive effect of EM was only noted in the case of plants cultivated under blue-red fluorescent light. Considering plants without microbial inoculation the highest levels were recorded in plants under red and blue light. The comparison of the effect of light quality revealed that in all colours a higher or similar level of net photosynthetic rate was noted in plants under LEDs. Mostly the higher photosynthetic activity was connected with higher stomatal opening as well as with higher transpiration rate, which is especially true for plants cultivated under red and blue LED light.

scholarly journals Extensometer for Determining Strains on a Tensile and Torsion Simultaneous Load

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 385
Author(s):  
Viorel Goanta
Keyword(s):  
Simultaneous Measurement ◽  
Tensile Load ◽  
Longitudinal Axis ◽  
The Other ◽  
Bending Moments ◽  
Strain Process ◽  
Electric Signals ◽  
Measured Process

The paper presents an extensometer designed to measure two mechanical strains at the same time—one from tensile load and the other from torsion load. Strain transducers provide different electric signals, which, after calibration, lead to the simultaneous measurement of linear (ε) and angular (γ) strains. Each of these two signals depends on the measured process and is not influenced by the other strain process. This extensometer is designed to be easily mounted on the sample with only two mounting points and can be used to measure the combined cyclical fatigue of tensile and torsional loadings. This extensometer has two bars—one rigid, reported at the resulting stress points, and one elastic and deformable. The elastic deformable bar has two beams with different orientations. When the sample is deformed, both beams are loaded by two bending moments (perpendicular to each other and both perpendicular on the longitudinal axis of the bars).

CORTICOTROPHIN RELEASE IN MICE: FAILURE OF PENTOBARBITAL-MORPHINE TO BLOCK THE EFFECT OF NON-SPECIFIC STRESS

1964 ◽  
Vol 46 (3) ◽  
pp. 387-392 ◽  
Author(s):  
Claus Rerup
Keyword(s):  
Direct Effect ◽  
Intravenous Injection ◽  
Blocking Effect ◽  
The Other ◽  
Marked Contrast ◽  
Hypothalamic Extract ◽  
Adrenal System ◽  
Hormonal System

ABSTRACT Corticotrophin release in mice was determined from plasma free corticosteroid levels. The blocking effect of dexamethasone against non-specific stress was compared with that of pentobarbital-morphine. In marked contrast to the findings in the rat, pentobarbital-morphine pretreatment in mice did not prevent the activation of the pituitary-adrenal hormonal system, following the non-specific stress of histamine injection. Pentobarbital-morphine thus does not render the mouse a specific in vivo preparation for the determination of corticotrophin releasing activity (CRA). Dexamethasone, on the other hand, appears to be effective in blocking corticotrophin release due to non-specific stress and allowed of activation of the pituitary-adrenal system after intravenous injection of vasopressin and hypothalamic extract only. The steroid had no direct effect on the adenohypophysis.

DIRECT AND INDIRECT EFFECTS OF SOCIAL SUPPORT ON PSYCHOLOGICAL WELL-BEING

2004 ◽  
Vol 32 (5) ◽  
pp. 449-458 ◽  
Author(s):  
Tülin Gençöz ◽  
Yeşim Özlale ◽  
Randy Lennon
Keyword(s):  
Social Support ◽  
University Students ◽  
Direct Effect ◽  
Indirect Effects ◽  
Well Being ◽  
The Other ◽  
Depression Symptoms ◽  
Direct And Indirect Effects ◽  
Psychological Well Being ◽  
Undergraduate University Students

The aim of this study was to investigate the direct and indirect effects of social support on psychological well-being. Social support was evaluated under two different categories which were named as Aid-Related and Appreciation-Related Socia+l Support. The first category was more related to potential for receiving help from others when needed, and being cared for by others, while the latter category was more related to being recognized by others as an efficient source of help and reassurance of worth. Undergraduate university students (N =342) served as subjects, and results revealed that aid-related social support and psychological well-being (i.e., alleviated depression symptoms) association was partially mediated by experiencing fewer life stresses. On the other hand, appreciation-related social support had a direct effect on psychological well-being. Implications of these results are discussed.

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