scholarly journals THE LIGHT GROWTH RESPONSE AND THE GROWTH SYSTEM OF PHYCOMYCES

1935 ◽  
Vol 18 (3) ◽  
pp. 385-397 ◽  
Author(s):  
E. S. Castle ◽  
A. J. M. Honeyman
Keyword(s):  
Reaction Time ◽  
Growth Response ◽  
Total Elongation ◽  
Limiting Factor ◽  
Outermost Layer ◽  
Long Latency ◽  
Time Component ◽  
Growth System ◽  
Time Required ◽  
Mechanism Of Growth

1. The Roscoe-Bunsen law holds for the light growth response of Phycomyces if the time component of stimulation is short. With exposures longer than a few seconds, the reaction time to light is determined by the intensity and not by the energy of the flash. 2. The possible nature of the very long latency in the response to light is considered in terms of the structure of the cell and its mechanism of growth. It is suggested that during the latency some substance produced by light in the protoplasm is transported centrifugally to the cell wall or outermost layer of protoplasm. 3. The total elongation occurring over a period of 1 to 2 hours is independent of flashes of light or temporary darkening. Light acts by facilitating some change already under way in the growth system, and during the principal phase of elongation is not a necessary or limiting factor for growth. 4. Judged by the reaction time, the original sensitivity is restored in the light system following exposure to light in about one-third the time required for equilibrium to be reattained in the growth system.

Dysequilibrium Reaction Time and “Long-Loop” Recruitment Deficits in Subjects with Hemiplegia

1992 ◽  
Vol 12 (4) ◽  
pp. 229-241
Author(s):  
Richard P. DiFabio ◽  
Mary Beth Badke ◽  
Ann Breunig
Keyword(s):  
Reaction Time ◽  
Stretch Reflex ◽  
Onset Time ◽  
Reflex Response ◽  
Body Sway ◽  
Limiting Factor ◽  
Postural Reflex ◽  
Time Required ◽  
Gastrocnemius Muscles ◽  
Postural Muscles

Gaps in the recruitment of postural muscles to correct body sway may be a limiting factor in the rehabilitation of patients with stroke. The purpose of this study was to determine how the onset of a postural reflex compares to the conscious identification of body sway in patients with hemiplegia and in a comparison group of able-bodied subjects. All subjects stood on a movable force platform that was unexpectedly displaced backwards inducing a forward body sway. The excursion and velocity of the platform displacements were varied systematically and the frequency of activation of postural muscles was recorded. A hand held response key was used to measure the time required to react to the postural disturbance (RT). In addition, the onset time of a long-loop “stretch” reflex was measured in the gastrocnemius muscles bilaterally. Subjects with hemiplegia failed to recruit a reflex response in 53% of the trials, whereas able-bodied subjects had an absent response in only 3% of the trials. The upper extremity RT for subjects with hemiplegia was not significantly delayed compared to able-bodied subjects, and the onset of a stretch reflex response in the gastrocnemius muscles was not different between groups. In addition, there was no correlation between reflex onset and conscious reaction time for control or disabled groups. These results have implications for the practice of occupational therapy because lower extremity recruitment deficits may persist and require treatment even though the recognition of body sway and the onset of reflex muscle discharge (when recruited) was similar to that of able-bodied subjects.

scholarly journals Smart Headgear for Assessment of Auditory Response Reaction Time of Professional and Amateur Kendokas

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 93
Author(s):  
Kwangyul Jeong ◽  
Adin Ming Tan ◽  
Yehuda Weizman ◽  
Franz Konstantin Fuss
Keyword(s):  
Reaction Time ◽  
Pressure Sensor ◽  
Average Reaction Time ◽  
Significant Difference ◽  
Auditory Response ◽  
Time Required

In Kendo, the ability to execute a technique within the shortest time is essential for winning. The purpose of this study was to utilise an in-house developed automatic headgear-scoring sensor with a buzzer to determine the auditory response reaction time (ARRT) of professional (PK) and amateur (AK) Kendo practitioners. ARRT is defined as the time required for a participant to hit a target after a buzzer is sounded. A total of 14 participants took part in this study. The participants were requested to hit the opponent’s headgear target, which consisted of a pressure sensor, upon hearing the buzzer. The average reaction time of PK is 0.44 s, and for AK 0.58 s, with a significant difference between the two groups (p < 0.0001). The in-house developed automatic headgear-scoring sensor with buzzer can be utilised to assist a Kendo practitioner in training to shorten the response reaction time to improve competition performance.

scholarly journals University of Miami Radiocarbon Dates VI

Radiocarbon ◽  
1976 ◽  
Vol 18 (2) ◽  
pp. 210-220 ◽  
Author(s):  
J J Stipp ◽  
K L Eldridge ◽  
R Cadwell
Keyword(s):  
Standard Deviation ◽  
Reaction Time ◽  
Liquid Scintillation Counting ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Correction Factors ◽  
Lithium Metal ◽  
Radiocarbon Dates ◽  
Partial List ◽  
Time Required

The following radiocarbon measurements are a partial list of projects and samples dated since the Spring of 1975. The technique used is liquid scintillation counting of wholly synthesized benzene as indicated in R, v 16, p 402-408. The intermediate chemical step of converting CO2 to Li2C2 has been modified so that the CO2 is reacted with the lithium metal at a temperature of 950° to 1000°C instead of the 600°C as formerly done (Tamers, 1975). This modification has had the effect of reducing occasional variable losses in conversion yields in this step, and reducing the reaction time required from 30 min to 10 min for a typical ¼ mole sample. Dates are calculated using a 14C half-life of 5568 yr and errors are reported as one standard deviation. No other correction factors are applied.

scholarly journals Are Commonly Measured Functional Traits Involved in Tropical Tree Responses to Climate?

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Fabien Wagner ◽  
Vivien Rossi ◽  
Christopher Baraloto ◽  
Damien Bonal ◽  
Clément Stahl ◽  
...  
Keyword(s):  
Functional Traits ◽  
Tree Growth ◽  
Water Availability ◽  
Growth Response ◽  
Climate Models ◽  
Growth Strategy ◽  
Limiting Factor ◽  
Maximum Height ◽  
Growth Strategies ◽  
Growth Responses

Climate models predict significant rainfall reduction in Amazonia, reducing water availability for trees. We present how functional traits modulate the tree growth response to climate. We used data from 3 years of bimestrial growth measurements for 204 trees of 53 species in the forest of Paracou, French Guiana. We integrated climate variables from an eddy covariance tower and functional trait values describing life history, leaf, and stem economics. Our results indicated that the measured functional traits are to some extent linked to the response of trees to climate but they are poor predictors of the tree climate-induced growth variation. Tree growth was affected by water availability for most of the species with different species growth strategies in drought conditions. These strategies were linked to some functional traits, especially maximum height and wood density. These results suggest that (i) trees seem adapted to the dry season at Paracou but they show different growth responses to drought, (ii) drought response is linked to growth strategy and is partly explained by functional traits, and (iii) the limited part of the variation of tree growth explained by functional traits may be a strong limiting factor for the prediction of tree growth response to climate.

Kinetic Analysis on SiC Prepared by Carbothermic Method

2012 ◽  
Vol 550-553 ◽  
pp. 2745-2748
Author(s):  
Bin Hao ◽  
Jin Qiang Liu ◽  
Fu Wang
Keyword(s):  
Silicon Carbide ◽  
Reaction Time ◽  
Dynamic Analysis ◽  
Kinetic Analysis ◽  
Kinetic Parameters ◽  
Particle Diameter ◽  
Thermal Reduction ◽  
Different Temperatures ◽  
Time Required

Kinetic analysis of silicon carbide prepared by carbon-thermal reduction is introduced in this paper. Through the dynamic analysis, kinetic parameters of Si-C are calculated, and it is estimated that the time required reaction materials of different diameter completely converted to SiC at different temperatures. Reaction time is nearly 1 hour long when the reaction particle diameter is 1μm around 1900K.

scholarly journals The P4 Parallel Programming System, the Linda Environment, and Some Experiences with Parallel Computation

1993 ◽  
Vol 2 (3) ◽  
pp. 23-35
Author(s):  
Allan R. Larrabee
Keyword(s):  
Integrated Circuits ◽  
Parallel Computation ◽  
Limiting Factor ◽  
Task Parallelism ◽  
Programming System ◽  
Von Neumann ◽  
Remote Storage ◽  
Time Required ◽  
Von Neumann Architecture ◽  
Silicon Based

The first digital computers consisted of a single processor acting on a single stream of data. In this so-called "von Neumann" architecture, computation speed is limited mainly by the time required to transfer data between the processor and memory. This limiting factor has been referred to as the "von Neumann bottleneck". The concern that the miniaturization of silicon-based integrated circuits will soon reach theoretical limits of size and gate times has led to increased interest in parallel architectures and also spurred research into alternatives to silicon-based implementations of processors. Meanwhile, sequential processors continue to be produced that have increased clock rates and an increase in memory locally available to a processor, and an increase in the rate at which data can be transferred to and from memories, networks, and remote storage. The efficiency of compilers and operating systems is also improving over time. Although such characteristics limit maximum performance, a large improvement in the speed of scientific computations can often be achieved by utilizing more efficient algorithms, particularly those that support parallel computation. This work discusses experiences with two tools for large grain (or "macro task") parallelism.

Denitrification with corncob as carbon source and biofilm carriers

2012 ◽  
Vol 65 (7) ◽  
pp. 1238-1243 ◽  
Author(s):  
Guochao Li ◽  
Jie Chen ◽  
Tao Yang ◽  
Jianqi Sun ◽  
Shenglu Yu
Keyword(s):  
Reaction Time ◽  
Carbon Source ◽  
Nitrate Nitrogen ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Limiting Factor ◽  
Nitrate N ◽  
Biofilm Carrier ◽  
Laboratory Reactor ◽  
Control Batch

In this research the agricultural by-product corncob was investigated as a carbon source as well as a biofilm carrier to remove organic matter, expressed as chemical oxygen demand (COD) and nitrate nitrogen (nitrate-N), from wastewater in a batch laboratory reactor. The performance of a reactor with corncob as the carbon source and the biofilm carrier was compared with a control batch reactor with suspended plastic carriers and glucose as the sole carbon source. With 60 vol% of corncob carriers inside the reactor, a soluble COD/N ratio of 4.2 g COD g N−1 was enough for total denitrification, nearly half of the control reactor (9.5 g COD g N−1), at 23 h reaction time. The specific denitrification rate decreased with increasing soluble COD consumption for both reactors. Nitrate and COD removal efficiencies decreased with shorter retention times, with accentuated effects in the reactor. This study suggested corncob as a feasible carbon source and that reaction time was a limiting factor with corncob used as the carbon source for denitrification.

Removal of ammonium as struvite using magnesite as a source of magnesium ions

2010 ◽  
Vol 5 (1) ◽  
Author(s):  
H. M. Huang ◽  
X. M. Xiao ◽  
L. P. Yang ◽  
B. Yan
Keyword(s):  
Reaction Time ◽  
Reaction Rate ◽  
Low Cost ◽  
Magnesium Ions ◽  
Batch Experiments ◽  
Optimum Conditions ◽  
Ammonium Removal ◽  
Time Required ◽  
Solid Liquid ◽  
Operation Cost

In this study, magnesite was used as a low-cost magnesium source to remove ammonium as struvite from the wastewater generated in the rare-earth elements separation process. Since the solubility of magnesite is low, before it was used it was decomposed to magnesia which has a higher reaction rate than magnesite. To optimize its usage, the optimum temperature of decomposition of magnesite and the time required for the process were determined by batch experiments to be 700 °C and 1.5 h, respectively. Besides, batch experiments using the residues of magnesite decomposed under optimum conditions were undertaken to investigate the effects of solid (magnesite)/liquid (wastewater) ratio and reaction time on ammonium removal as struvite. Results indicated that for the solid/liquid ratios tested and for a reaction time of 6 h, phosphorus concentrations fell steeply from the initial 9105 mg/L to a range of 198.8–29.8 mg/L, and ammonium concentrations from the initial 5287 mg/L to 540–520 mg/L. An economic analysis conducted indicated that the operation cost of the struvite process could be reduced by about 34% using decomposed magnesite instead of pure MgCl2.

scholarly journals Diurnal Variation in Visual Simple Reaction Time between and within Genders in Young Adults: An Exploratory, Comparative, Pilot Study

2021 ◽  
Vol 2021 ◽  
pp. 1-5
Author(s):  
Hanumantha S ◽  
Ashwin Kamath ◽  
Rajeshwari Shastry
Keyword(s):  
Reaction Time ◽  
Pilot Study ◽  
Simple Reaction Time ◽  
Time Of Day ◽  
Practice Session ◽  
Language Version ◽  
Simple Reaction ◽  
Parallel Group ◽  
Significant Difference ◽  
Time Required

Simple reaction time (SRT) is the minimum time required to respond to a stimulus; it is a measure of processing speed. Our study aimed to determine the variation in visual SRT with time among individuals of the same gender and between genders. We carried out a prospective, parallel group, pilot study involving ten male and ten female medical students aged 18–25 years. After obtaining written informed consent, the participants were familiarized with the procedures, and each completed a single practice session of a computerized visual SRT which was administered using Psychology Experiment Building Language Version 2.0 software. On a predetermined day, the participants completed the exercise at 10 a.m., 1 p.m., and 5 p.m. The results showed no statistically significant difference in SRT based on time of day between genders (χ2(2) = 4.300, p = 0.116 ) as well as within gender (males (χ2(2) = 0.600, p = 0.741 ); females (χ2(2) = 5.000, p = 0.082 ). Our study showed that visual SRT does not change significantly at different times of the day and within and between genders. Intraindividual variations in visual SRT can mask the presence of a small but significant difference; hence, further studies are warranted.

scholarly journals Voluntary reaction time and long-latency reflex modulation

2015 ◽  
Vol 114 (6) ◽  
pp. 3386-3399 ◽  
Author(s):  
Christopher J. Forgaard ◽  
Ian M. Franks ◽  
Dana Maslovat ◽  
Laurence Chin ◽  
Romeo Chua
Keyword(s):  
Reaction Time ◽  
Reflex Modulation ◽  
Electromyographic Activity ◽  
Gain Modulation ◽  
Voluntary Activity ◽  
Reflex Mechanism ◽  
Voluntary Response ◽  
Long Latency ◽  
Reflex Gain ◽  
Long Latency Reflex

Stretching a muscle of the upper limb elicits short (M1) and long-latency (M2) reflexes. When the participant is instructed to actively compensate for a perturbation, M1 is usually unaffected and M2 increases in size and is followed by the voluntary response. It remains unclear if the observed increase in M2 is due to instruction-dependent gain modulation of the contributing reflex mechanism(s) or results from voluntary response superposition. The difficulty in delineating between these alternatives is due to the overlap between the voluntary response and the end of M2. The present study manipulated response accuracy and complexity to delay onset of the voluntary response and observed the corresponding influence on electromyographic activity during the M2 period. In all active conditions, M2 was larger compared with a passive condition where participants did not respond to the perturbation; moreover, these changes in M2 began early in the appearance of the response (∼50 ms), too early to be accounted for by voluntary overlap. Voluntary response latency influenced the latter portion of M2, with the largest activity seen when accuracy of limb position was not specified. However, when participants aimed for targets of different sizes or performed movements of various complexities, reaction time differences did not influence M2 period activity, suggesting voluntary activity was sufficiently delayed. Collectively, our results show that while a perturbation applied to the upper limbs can trigger a voluntary response at short latency (<100 ms), instruction-dependent reflex gain modulation remains an important contributor to EMG changes during the M2 period.

Sign in / Sign up

Export Citation Format

Share Document