scholarly journals Two maize cultivars of contrasting leaf size show different leaf elongation rates with identical patterns of extension dynamics and coordination

AoB Plants ◽  
2021 ◽  
Author(s):  
Tiphaine Vidal ◽  
Hafssa Aissaoui ◽  
Sabrina Rehali ◽  
Bruno Andrieu
Keyword(s):  
Genotypic Variation ◽  
Leaf Size ◽  
High Rate ◽  
Time Interval ◽  
Extension Rate ◽  
Leaf Production ◽  
Maize Cultivars ◽  
Plant Environment ◽  
The Difference ◽  
Leaf Extension

Abstract Simulating leaf development from initiation to maturity opens new possibilities to model plant–environment interactions and the plasticity of plant architecture. This study analyses the dynamics of leaf production and extension along a maize (Zea mays) shoot to assess important modelling choices. Maize plants from two cultivars originating from the same inbred line, yet differing in the length of mature leaves were used in this study. We characterised the dynamics of the blade and sheath lengths of all phytomers by dissecting plants every 2–3 days. We analysed how differences in leaf size were built up and we examined the coordination between the emergence of organs and phases of their extension. Leaf extension rates were higher in the cultivar with longer leaves than in the cultivar with shorter leaves; no differences were found in other aspects. We found that (i) first post-embryonic leaves were initiated at a markedly higher rate than upper leaves; (ii) below ear position, sheaths were initiated at a time intermediate between tip emergence and appearance, while above the ear position, sheaths were initiated at a high rate, such that the time interval between the blade and sheath initiations decreased for these leaves; and (iii) ear position also marked a change in the correlation in size between successive phytomers with little correlation of size between upper and lower leaves. Our results identified leaf extension rate as the reason for the difference in size between the two cultivars. The two cultivars shared the same pattern for the timing of initiation events, which was more complex than previously thought. The differences described here may explain some inaccuracies reported in functional-structural plant models. We speculate that genotypic variation in behaviour for leaf and sheath initiation exists, which has been little documented in former studies.

Morphogenetic and structural characteristics of field-grown timothy cultivars differing in maturity

1996 ◽  
Vol 76 (2) ◽  
pp. 277-282 ◽  
Author(s):  
G. Bélanger
Keyword(s):  
Structural Characteristics ◽  
Leaf Size ◽  
Phleum Pratense ◽  
Extension Rate ◽  
Primary Growth ◽  
Early Maturing ◽  
Tiller Density ◽  
Leaf Appearance ◽  
Leaf Extension ◽  
Phleum Pratense L

The leaf area development of grasses and, subsequently, radiation interception depends on morphogenetic processes such as leaf extension and appearance. No detailed studies of leaf extension and appearance of field-grown timothy (Phleum pratense L.) cultivars differing in maturity have been reported in the literature. Leaf extension and appearance of field-grown timothy cultivars differing in maturity and their impact on sward structural characteristics such as leaf size per tiller and tiller density were studied during primary growth in the spring of 1991 and 1992. The leaf extension rate of early-maturing cultivars was greater than that of late-maturing cultivars during primary growth of timothy. There were no differences in leaf appearance rates among cultivars Hence, individual tillers of early-maturing cultivars developed a larger leaf size than late-maturing cultivars. In 1992, late-maturing cultivars had a greater tiller density than early-maturing cultivars which compensated for the smaller leaf size. Different tiller density-tiller size characteristics of early and late-maturing timothy cultivars resulted in a similar outcome in terms of LAI. Key words:Phleum pratense L., timothy, leaf extension, leaf appearance, tillering

scholarly journals Seasonal patterns of root, tiller and leaf production in a Grasslands Ruanui ryegrass sward

1996 ◽  
pp. 73-76
Author(s):  
C. Matthew
Keyword(s):  
Principal Component Analysis ◽  
Root Formation ◽  
Principal Component ◽  
Component Analysis ◽  
Seasonal Patterns ◽  
Extension Rate ◽  
Leaf Production ◽  
Leaf Formation ◽  
Leaf Appearance ◽  
Leaf Extension

In a Grasslands Ruanui perennial ryegrass (Lofium perenne L.) sward at Palmerston North, root mass, root appearance, tiller population density, tiller appearance and death rates, and leaf extension and leaf appearance rates were measured at 2-monthly intervals over a 12-month period, commencing November 1988. Tiller appearance was lowest in November, but was also low in May, increasing to a peak in August. Root appearance showed a pronounced peak in August. Leaf extension and leaf appearance rates were low during the period of high root and tiller formation in August, but high in November when tiller and root formation were low, suggesting co-ordination of these processes, with sequential activation of tillering, root formation and leaf formation activity winter. Principal component analysis to gain an objective overview of these data indicated a primary peak of activity in August (spring), and a secondary peak in March (autumn). The seasonal patterns observed for Grasslands Ruanui ryegrass appear to be different from those reported in the literature for Ellett and Grasslands Nui cultivars. ---.----._- - - - Keywords: leaf extension rate, Lolium perenne, principal component analysis, root growth, tiller appearance

Peritoneal Fluid and Plasma Fibrinolytic Activity in Women with Pelvic Inflammatory Disease

1992 ◽  
Vol 68 (02) ◽  
pp. 102-105 ◽  
Author(s):  
P J Dörr ◽  
E J P Brommer ◽  
G Dooijewaard ◽  
H M Vemer
Keyword(s):  
Pelvic Inflammatory Disease ◽  
Inflammatory Disease ◽  
Peritoneal Fluid ◽  
Fibrinolytic Activity ◽  
Degradation Products ◽  
Adhesion Formation ◽  
High Rate ◽  
Control Group ◽  
The Difference ◽  
Fibrinolytic Parameters

SummaryPrevious studies have shown that the fibrinolytic activity of peritoneum is depressed in local inflammation. We measured fibrinolytic parameters in peritoneal fluid and in plasma of 10 women with pelvic inflammatory disease (PID). Nine women, in whom laparoscopy for sterilisation was performed, served as a control group.In the peritoneal fluid of women with PID, PAI-Ag, t-PA-Ag and u-PA-Ag were many times higher than in the control group. In contrast to the antigens which may be present in inert complexes, the potentially active compounds, measured as t-PA activity and plasmin-activable scu-PA, were not significantly different in the two groups, and in none of the samples was the active enzyme tcu-PA detectable. Nevertheless, the mean peritoneal fluid TDP and FbDP concentrations were about twenty times higher in the PID group than in the control group. In plasma of PID patients, none of the parameters except u-PA-Ag differed from those in the control group. The difference between control and patient plasma u-PA-Ag was statistically significant, but too small to attach any relevance to the observation.Our data suggest that, in contrast to the classical concept of decreased fibrinolytic activity as a cause of adhesion formation, intraperitoneal fibrinolysis is enhanced in peritoneal inflammation through stimulation of the local production of t-PA and u-PA. Despite concomitant production of PAI, fibrinolysis occurs at a high rate, resulting in high levels of fibrin degradation products. Since this activated fibrinolysis does not meet the demand, therapeutic enhancement should be considered to prevent adhesions.

scholarly journals A scoping review of chronotype and temporal patterns of eating of adults: Tools used, findings, and future directions

2021 ◽  
pp. 1-51
Author(s):  
Yan Yin Phoi ◽  
Michelle Rogers ◽  
Maxine P. Bonham ◽  
Jillian Dorrian ◽  
Alison M. Coates
Keyword(s):  
Energy Intake ◽  
Scoping Review ◽  
Assessment Tool ◽  
Temporal Patterns ◽  
Time Interval ◽  
Dark Cycle ◽  
Future Directions ◽  
Meal Skipping ◽  
Optimal Health ◽  
The Difference

Abstract Circadian rhythms, metabolic processes, and dietary intake are inextricably linked. Timing of food intake is a modifiable temporal cue for the circadian system and may be influenced by numerous factors, including individual chronotype—an indicator of an individual’s circadian rhythm in relation to the light-dark cycle. This scoping review examines temporal patterns of eating across chronotypes and assesses tools that have been used to collect data on temporal patterns of eating and chronotype. A systematic search identified thirty-six studies in which aspects of temporal patterns of eating including meal timings; meal skipping; energy distribution across the day; meal frequency; time interval between meals, or meals and wake/sleep times; midpoint of food/energy intake; meal regularity; and duration of eating window were presented in relation to chronotype. Findings indicate that compared to morning chronotypes, evening chronotypes tend to skip meals more frequently, have later mealtimes, and distribute greater energy intake towards later times of the day. More studies should explore the difference in meal regularity and duration of eating window amongst chronotypes. Currently, tools used in collecting data on chronotype and temporal patterns of eating are varied, limiting the direct comparison of findings between studies. Development of a standardised assessment tool will allow future studies to confidently compare findings to inform the development and assessment of guidelines that provide recommendations on temporal patterns of eating for optimal health.

LONG‐TIME RESPONSE PREDICTED BY EXACT ELASTIC RAY THEORY

Geophysics ◽  
1965 ◽  
Vol 30 (3) ◽  
pp. 363-368 ◽  
Author(s):  
T. W. Spencer
Keyword(s):  
Formal Solution ◽  
Intermediate Stage ◽  
Time Limit ◽  
Time Interval ◽  
Individual Response ◽  
Axially Symmetric ◽  
Long Time ◽  
The Difference ◽  
The Individual ◽  
Significant Figures

The formal solution for an axially symmetric radiation field in a multilayered, elastic system can be expanded in an infinite series. Each term in the series is associated with a particular raypath. It is shown that in the long‐time limit the individual response functions produced by a step input in particle velocity are given by polynomials in odd powers of the time. For rays which suffer m reflections, the degree of the polynomials is 2m+1. The total response is obtained by summing all rays which contribute in a specified time interval. When the rays are selected indiscriminately, the difference between the magnitude of the partial sum at an intermediate stage of computation and the magnitude of the correct total sum may be greater than the number of significant figures carried by the computer. A prescription is stated for arranging the rays into groups. Each group response function varies linearly in the long‐time limit and goes to zero when convolved with a physically realizable source function.

Post-stroke cognitive impairment: screening with MMSE and MoCA and predictors of their persistence after treatment at the Stroke Center

2021 ◽  
Author(s):  
Y. V. Flomin ◽  
V. G. Gurianov ◽  
L. I. Sokolova
Keyword(s):  
Cognitive Impairment ◽  
Mmse Score ◽  
Cerebral Arteries ◽  
High Rate ◽  
Cerebral Stroke ◽  
Time Interval ◽  
Post Stroke ◽  
Lower Baseline ◽  
Stroke Center ◽  
Moca Score

Objective — to analyze the results of screening for post‑stroke cognitive impairment (PCI) in patients with cerebral stroke (CS) admitted to the Stroke Center (SC) in different disease phases, and to determine independent predictors of the PCI persistence at discharge. Methods and subjects. 399 patients were enrolled, including 242 (60.7 %) men and 157 (39.3 %) women with the median age was 66.2 years (IQR 58.5 — 76.3). IS was diagnosed in 331 (82.9 %), and ICH in 68 (17.1 %) patients. Among patients with IS, 137 (41.4 %) had an atherothrombotic subtype, 152 (46.0 %) had a cardioembolic subtype, 21 (6.3 %) had a lacunar subtype, another 21 (6.3 %) had another or unknown cause of stroke. Patients were screened for PCI using the Mini‑Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) on admission and at discharge. Participants with MMSE score of 0 — 24 or a MoCA score of 0 — 25 were considered having PCI. Upon admission, all patients were assessed using the National Institutes of Health Stroke Scale (NIHSS), Bartel Index, and Modified Rankine Scale (mRS). The method of constructing and analyzing logistic regression models was used to determine independent predictors of the preservation of PCI at discharge. The analysis was carried out using the MedCalc v. 19.1. Results. The baseline NIHSS score ranged from 0 to 39 (median 11, IQR 6 — 18). The majority (64.2 %) of the subjects were hospitalized within the first 30 days from the CS onset. The MMSE score on admission ranged from 0 to 30 (median 20, IQR 2 — 27), and in 179 (44.9 %) of the patients the initial score was 0 to 17 (severe PCI), whereas in 61 (15 3 %) of the participants it was 18 to 24 (moderately severe PCI) and only 159 (39.8 %) persons scored 25 to 30 (no PCI). The baseline MoCA score ranged from 0 to 30 (median 15, IQR 1 — 24), and 356 (89.2 %) patients were shown to have PCI (score 0 to 25). According to screening with MMSE at discharge, 125 (31.4 %) patients had severe PCI, and 67 (16.8 %) had moderately severe PCI. The MoCA assessment before discharge indicated PCI in 324 (81.2 %) patients. According to both MMSE and MoCA, the rate of PCI on admission was significantly higher than at discharge (p < 0.001). Among the 240 patients who had PCI according to MMSE score, 239 (99.6 %) had PCI according to the MoCA score. However, among 159 patients who screened negative for PCI with MMSE at admission, 117 (73.6 %) screened positive with MoCA. Screening results using both MMSE and MoCA were not significantly associated with affected hemisphere. ICH was associated with lower (p < 0.0001) MMSE and MoCA scores compared with IS. Predictors of PCI according to MMSE score at discharge were a longer time interval from CS onset to SC admission, and a lower baseline MMSE score. However, with MoCA, the predictors were AT subtype IS, lesions in the distribution of the right or both middle cerebral arteries, older patient age, and a lower baseline MoCA score. Conclusions. In patients with MI, a high rate of PCI was documented on admission, but was significantly lower at discharge. In patients with established PCI, according to MMSE score, the use of MoCA for screening seems useless, however, screening with MoCA identified PCI in 3/4 in patients with a normal MMSE score. The independent predictors of scores on these two scales, indicating PCI, were significantly different, so they should not be considered interchangeable.

Synchronization of cardiac-related discharges of sympathetic nerves with inputs from widely separated spinal segments

1995 ◽  
Vol 268 (6) ◽  
pp. R1472-R1483 ◽  
Author(s):  
G. L. Gebber ◽  
S. Zhong ◽  
S. M. Barman
Keyword(s):  
Phase Angle ◽  
Cervical Spinal Cord ◽  
Sympathetic Nerves ◽  
Time Interval ◽  
Renal Nerve ◽  
Cardiac Nerve ◽  
Spinal Segments ◽  
The Difference ◽  
Decerebrate Cats ◽  
Inferior Cardiac Nerve

We used phase spectral analysis to study the relationships between the cardiac-related discharges of pairs of postganglionic sympathetic nerves in urethan-anesthetized or decerebrate cats. Phase angle when converted to a time interval should equal the difference in conduction times from the brain to the nerves (i.e., transportation lag) if their cardiac-related discharges have a common central source. Transportation lag was estimated as the difference in the onset latencies of activation of the nerves by electrical stimulation of the medulla or cervical spinal cord. The phase angle for the cardiac-related discharges of two nerves was not always equivalent in time to the transportation lag. For example, in some cases the cardiac-related discharges of the renal nerve were coincident with or led those of the inferior cardiac nerve. In contrast, the electrically evoked responses of the renal nerve lagged those of the inferior cardiac nerve by > or = 32 ms. These observations are consistent with a model of multiple and dynamically coupled brain stem generators of the cardiac-related rhythm, each controlling a different sympathetic nerve or exerting nonuniform influences on different portions of the spinal sympathetic outflow.

scholarly journals The effect of diminazene aceturate on cholinesterase activity in dogs with canine babesiosis

1997 ◽  
Vol 68 (4) ◽  
Author(s):  
R.J. Milner ◽  
F. Reyers ◽  
J.H. Taylor ◽  
J.S. Van den Berg
Keyword(s):  
Treatment Group ◽  
Underlying Mechanism ◽  
Time Interval ◽  
Control Groups ◽  
Canine Babesiosis ◽  
Diminazene Aceturate ◽  
Time Intervals ◽  
Significant Depression ◽  
The Difference ◽  
And Control

A clinical trial was designed to evaluate the effects of diminazene aceturate and its stabiliser antipyrine on serum pseudocholinesterase (PChE) and red blood cell acetylcholinesterase (RBC AChE) in dogs with babesiosis. The trial was conducted on naturally occurring, uncomplicated cases of babesiosis (n = 20) that were randomly allocated to groups receiving a standard therapeutic dose of diminazene aceturate with antipyrine stabiliser (n = 10) or antipyrine alone (n = 10). Blood was drawn immediately before and every 15 minutes for 1 hour after treatment. Plasma PChE showed a 4 % decrease between 0 and 60 min within the treatment group (p < 0.05). No statistically significant differences were found between the treatment and control groups at any of the time intervals for PChE. There was an increase in RBC AChE activity at 15 min in the treatment group (p < 0.05). No significant differences were found between the treatment and control groups at any time interval for RBC AChE. In view of the difference in PChE, samples from additional, new cases (n = 10) of canine babesiosis were collected to identify the affect of the drug over 12 hours. No significant depression was identified over this time interval. The results suggests that the underlying mechanism in producing side-effects, when they do occur, is unlikely to be through cholinesterase depression.

scholarly journals Value-at-risk modeling and forecasting with range-based volatility models: empirical evidence

2017 ◽  
Vol 28 (75) ◽  
pp. 361-376 ◽  
Author(s):  
Leandro dos Santos Maciel ◽  
Rosangela Ballini
Keyword(s):  
At Risk ◽  
Value At Risk ◽  
Garch Models ◽  
Time Interval ◽  
Risk Modeling ◽  
Additional Information ◽  
Volatility Models ◽  
Modeling And Forecasting ◽  
The Difference ◽  
Market Indexes

ABSTRACT This article considers range-based volatility modeling for identifying and forecasting conditional volatility models based on returns. It suggests the inclusion of range measuring, defined as the difference between the maximum and minimum price of an asset within a time interval, as an exogenous variable in generalized autoregressive conditional heteroscedasticity (GARCH) models. The motivation is evaluating whether range provides additional information to the volatility process (intraday variability) and improves forecasting, when compared to GARCH-type approaches and the conditional autoregressive range (CARR) model. The empirical analysis uses data from the main stock market indexes for the U.S. and Brazilian economies, i.e. S&P 500 and IBOVESPA, respectively, within the period from January 2004 to December 2014. Performance is compared in terms of accuracy, by means of value-at-risk (VaR) modeling and forecasting. The out-of-sample results indicate that range-based volatility models provide more accurate VaR forecasts than GARCH models.

The Retrieval of Marine Stratiform Cloud Properties from Multiple Observations in the 3.9-µm Window under Conditions of Varying Solar Illumination

1995 ◽  
Vol 34 (7) ◽  
pp. 1512-1524 ◽  
Author(s):  
Thomas J. Kleespies
Keyword(s):  
Climate Modeling ◽  
Thermal Structure ◽  
Cloud Microphysics ◽  
Time Interval ◽  
Short Time Interval ◽  
Cloud Parameters ◽  
Cloud Properties ◽  
Multiple Observations ◽  
Simplifying Assumptions ◽  
The Difference

Abstract Radiometric observations in the 3.9-µm region have been used by a number of investigators for the determination of cloud parameters or sea surface temperature at night. Only a few attempts have been made to perform quantitative assessments of cloud and surface properties during the daytime because of the inability to distinguish between the thermal and solar components of the satellite-sensed radiances. This paper presents a new method of separating the thermal and solar components of upwelling 3.9-µm radiances. Two collocated satellite observations are made under conditions where the solar illumination angle changes but the thermal structure of the cloud and atmosphere, as well as the cloud microphysics change very little. These conditions can easily be met by observing the same cloud from geosynchoronous orbit over a short time interval during the morning hours. When the radiances are differenced under these constraints, the thermal components cancel, and the difference in the radiances is simply the difference in the solar component. With a few simplifying assumptions, a cloud microphysical property, specifically effective radius, can be inferred. This parameter is of particular importance to both climate modeling and global change studies. The methodology developed in this paper is applied to data from the Visible-Infrared Spin Scan Radiometer Atmospheric Sounder onboard the GOES-7 spacecraft for a period in August 1992.

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