scholarly journals Linking dynamical complexities from activation signals to transcription responses

2019 ◽  
Vol 6 (3) ◽  
pp. 190286
Author(s):  
Genghong Lin ◽  
Feng Jiao ◽  
Qiwen Sun ◽  
Moxun Tang ◽  
Jianshe Yu ◽  
...  
Keyword(s):  
Temporal Variations ◽  
Growth Patterns ◽  
Carcinoma Cells ◽  
Genetic Circuit ◽  
High Frequencies ◽  
The Mean ◽  
Multiple Promoter ◽  
Activation Rates ◽  
Inducible Genes ◽  
State Selection

The transcription of inducible genes involves signalling pathways that induce DNA binding of the downstream transcription factors to form functional promoter states. How the transcription dynamics is linked to the temporal variations of activation signals is far from being fully understood. In this work, we develop a mathematical model with multiple promoter states to address this question. Each promoter state has its own activation and inactivation rates and is selected randomly with a probability that may change in time. Under the activation of constant signals, our analysis shows that if only the activation rates differ among the promoter states, then the mean transcription level m ( t ) displays only a monotone or monophasic growth pattern. In a sharp contrast, if the inactivation rates change with the promoter states, then m ( t ) may display multiphasic growth patterns. Upon the activation of signals that oscillate periodically, m ( t ) also oscillates later, almost periodically at the same frequency, but the magnitude decreases with frequency and is almost completely attenuated at high frequencies. This gives a surprising indication that multiple promoter states could filter out the signal oscillation and the noise in the random promoter state selection, as observed in the transcription of a gene activated by p53 in breast carcinoma cells. Our approach may help develop a theoretical framework to integrate coherently the genetic circuit with the promoter states to elucidate the linkage from the activation signal to the temporal profile of transcription outputs.

scholarly journals Temporal Variations of the Turbulence Profiles at the Sayan Solar Observatory Site

Atmosphere ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 499 ◽  
Author(s):  
Artem Shikhovtsev ◽  
Pavel Kovadlo ◽  
Vladimir Lukin
Keyword(s):  
Atmospheric Turbulence ◽  
Temporal Variability ◽  
Low Frequency ◽  
Temporal Variations ◽  
Solar Observatory ◽  
Vertical Profiles ◽  
Spatial And Temporal Scales ◽  
Atmospheric Disturbances ◽  
Wide Range ◽  
The Mean

The paper focuses on the development of the method to estimate the mean characteristics of the atmospheric turbulence. Using an approach based on the shape of the energy spectrum of atmospheric turbulence over a wide range of spatial and temporal scales, the vertical profiles of optical turbulence are calculated. The temporal variability of the vertical profiles of turbulence under different low-frequency atmospheric disturbances is considered.

A comparison of soil sampling procedures used to monitor soil fertility in permanent pastures

Soil Research ◽  
1984 ◽  
Vol 22 (1) ◽  
pp. 81 ◽  
Author(s):  
DK Friesen ◽  
GJ Blair
Keyword(s):  
Sampling Method ◽  
Nutrient Status ◽  
Temporal Variations ◽  
Cluster Sampling ◽  
Soil Test ◽  
Sampling Strategies ◽  
Grazed Pasture ◽  
The Mean ◽  
Sampling Procedures ◽  
Bray 1

Soil testing programs are often brought in disrepute by unexplained variability in the data. The deposition of dung and urine onto grazed pasture brings about marked variation in the chemical status of soils which contributes to this variability. A study was undertaken to compare a range of sampling procedures to estimate Colwell-P, Bray-1 P, bicarbonate K and pH levels in adjacent low and high P status paddocks. The sampling strategies used consisted of 75 by 50 m grids; whole and stratified paddock zig-zag and cluster (monitor plot) samplings. Soil test means for the various parameters did not vary among sampling methods. The number of grid samples required to estimate within 10% of the mean varied from 121 for Bray-1 P down to 1 for soil pH. Sampling efficiencies were higher for cluster sampling than for whole paddock zig-zag path sampling. Stratification generally did not improve sampling efficiency in these paddocks. Soil test means declined as sampling depth increased, but the coefficient of variation remained constant for Colwell-P and pH. The results indicate that cluster sampling (monitor plots) is the most appropriate procedure for estimating the nutrient status of grazed pastures. This sampling method enables a more accurate measure to be taken of the nutrient status of a paddock and should allow more reasonable estimates to be made of the temporal variations in soil test.

Chronopharmacological studies of phenylbutazone in the rat

1983 ◽  
Vol 61 (6) ◽  
pp. 649-652 ◽  
Author(s):  
G. Labrecquf ◽  
P. M. Bélanger ◽  
F. M. Doré
Keyword(s):  
Lethal Dose ◽  
Circadian Variation ◽  
Temporal Variations ◽  
Paw Edema ◽  
Lethal Effects ◽  
Ulcerogenic Effect ◽  
Small Doses ◽  
The Mean ◽  
Anti Inflammatory ◽  
Inflammatory Action

Temporal variations in the anti-inflammatory action and in the ulcerogenic and lethal effects of phenylbutazone were studied in rats. The results indicate that small doses of the drug produced a larger reduction of paw edema in the morning than in the evening. At 0900, doses of 10, 30, and 100 mg/kg of phenylbutazone reduced the carrageenan-induced paw edema by 23, 44, and 66%, respectively. At 2000, the same doses of the drug decreased the paw edema by 9, 22, and 62%, respectively. No circadian variation was observed in the ulcerogenic effect of phenylbutazone. The mean lethal dose (LD50) of the drug was larger in the morning than in the evening and the values obtained were 710 ± 24 (SE) mg/kg at 0900 in comparison to 525 ± 38 (SE) mg/kg at 2000.

scholarly journals When Density Matters: The Spatial Balance between Early and Latewood

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 818
Author(s):  
Maria Royo-Navascues ◽  
Edurne Martinez del Castillo ◽  
Roberto Serrano-Notivoli ◽  
Ernesto Tejedor ◽  
Klemen Novak ◽  
...  
Keyword(s):  
Species Distribution ◽  
Pinus Halepensis ◽  
Environmental Gradients ◽  
Temporal Variations ◽  
Western Mediterranean ◽  
Climatic Conditions ◽  
Growth Patterns ◽  
Distribution Area ◽  
Mediterranean Forests ◽  
Climatic Influence

Understanding the influence of the current climate on the distribution, composition, and carbon storage capacity of Mediterranean tree species is key to determining future pathways under a warmer and drier climate scenario. Here, we evaluated the influence of biotic and environmental factors on earlywood (EW) and latewood (LW) growth in Aleppo pine (Pinus halepensis Mill.). Our investigation was based on a dense dendrochronological network (71 sites), which covered the entire distribution area of the species in the Iberian Peninsula (around 119.652 km2), and a high-resolution climate dataset of the Western Mediterranean area. We used generalized linear-mixed models to determine the spatial and temporal variations of EW and LW across the species distribution. Our results showed an intense but differentiated climatic influence on both EW and LW growth components. The climatic influence explained significant variations across the environmental gradients in the study area, which suggested an important adaptation through phenotypic plasticity and local adaptation to varying climatic conditions. In addition, we detected a clear spatial trade-off between efficiency and safety strategy in the growth patterns across the species distribution. Additionally, in more productive areas, the trees presented a higher proportion of EW (more efficient to water transport), while, in more xeric conditions, the LW proportion increased (more safety to avoid embolisms), implying an adaptation to more frequent drought episodes and a higher capacity of carbon depletion. We therefore concluded that Mediterranean forests adapted to dryer conditions might be more efficient as carbon reservoirs than forests growing in wetter areas. Finally, we advocated for the need to consider wood density (EW/LW proportion) when modeling current and future forest carbon sequestrations.

scholarly journals Tropospheric temperature variation over India and links with the Indian summer monsoon : 1971-2000

MAUSAM ◽  
2022 ◽  
Vol 53 (3) ◽  
pp. 289-308
Author(s):  
D. R. KOTHAWALE ◽  
K. RUPA KUMAR
Keyword(s):  
Summer Monsoon ◽  
Southern Oscillation ◽  
Monsoon Season ◽  
Temporal Variations ◽  
Mean Annual Temperature ◽  
Tropospheric Temperature ◽  
Temperature Variations ◽  
Annual Cycles ◽  
The Mean ◽  
Spatio Temporal

In the context of the ever increasing interest in the regional aspects of global warming, understanding the spatio-temporal variations of tropospheric temperature over India is of great importance. The present study, based on the data from 19 well distributed radiosonde stations for the period 1971-2000, examines the seasonal and annual mean temperature variations at the surface and five selected upper levels, viz., 850, 700, 500, 200 and 150 hPa. An attempt has also been made to bring out the association between tropospheric temperature variations over India and the summer monsoon variability, including the role of its major teleconnection parameter, the El Niño/Southern Oscillation (ENSO).   Seasonal and annual mean all-India temperature series are analyzed for surface and five tropospheric levels.  The mean annual cycles of temperature at different tropospheric levels indicate that the pre-monsoon season is slightly warmer than the monsoon season at the surface, 850 hPa and 150 hPa levels, while it is relatively cooler at all intermediate levels.  The mean annual temperature shows a warming of 0.18° C and 0.3° C per 10 years at the surface and 850 hPa, respectively.   Tropospheric temperature anomaly composites of excess (deficient) monsoon rainfall years show pronounced positive (negative) anomalies during the month of May, at all the levels.  The pre-monsoon pressure of Darwin has significant positive correlation with the monsoon temperature at the surface and 850 hPa.

scholarly journals Spatial and temporal variations of CO<sub>2</sub> mole fractions observed at Beijing, Xianghe and Xinglong in North China

2021 ◽  
Author(s):  
Yang Yang ◽  
Minqiang Zhou ◽  
Ting Wang ◽  
Bo Yao ◽  
Pengfei Han ◽  
...  
Keyword(s):  
Seasonal Variations ◽  
Human Activities ◽  
North China ◽  
Terrestrial Ecosystem ◽  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
Boundary Layer Height ◽  
The Mean ◽  
The Impact ◽  
First Time

Abstract. Atmospheric CO2 mole fractions are observed at Beijing (BJ), Xianghe (XH), and Xinglong (XL) in North China using the Picarro G2301 Cavity Ring-Down Spectroscopy instruments. The measurement system is described comprehensively for the first time. The geo-distances among these three sites are within 200 km, but they have very different surrounding environments: BJ is inside the megacity; XH is in the suburban area; XL is in the countryside on a mountain. The mean and standard deviation of CO2 mole fractions at BJ, XH, and XL between October 2018 and September 2019 are 448.4 ± 12.8 ppm, 436.0 ± 9.2 ppm and 420.6 ± 8.2 ppm, respectively. The seasonal variations of CO2 at these three sites are similar, with a maximum in winter and a minimum in summer, which is dominated by the terrestrial ecosystem. However, the seasonal variations of CO2 at BJ and XH are more affected by human activities as compared to XL. By using CO2 at XL as the background, CO2 enhancements are observed simultaneously at BJ and XH. The diurnal variations of CO2 are driven by the boundary layer height, photosynthesis and human activities at BJ, XH and XL. Moreover, we address the impact of the wind on the CO2 mole fractions at BJ and XL. This study provides an insight into the spatial and temporal variations of CO2 mole fractions in North China.

scholarly journals Spatio-temporal variations of land surface temperature and precipitation due to climate change in the Jhelum river basin, India

MAUSAM ◽  
2021 ◽  
Vol 71 (4) ◽  
pp. 661-674
Author(s):  
HIMAYOUN DAR ◽  
ROSHNI THENDIYATH ◽  
MOHSIN FAROOQ
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
21St Century ◽  
Temporal Variations ◽  
Average Increase ◽  
Temperature And Precipitation ◽  
Rcp 8.5 ◽  
The Mean ◽  
Spatio Temporal ◽  
Precipitation And Temperature

The present study investigated the spatio-temporal variations of precipitation and temperature for the projected period (2011-2100) in the Jhelum basin, India. The precipitation and temperature variables are projected under RCP 8.5 scenario using statistical down scaling techniques such as Artificial Neural Network (ANN) and Wavelet Artificial Neural Network (WANN) models. Firstly, the screened predictors were downscaled to predictand using ANN and WANN models for all the study stations. On the basis of the performance criteria, the WANN model is selected as an efficient model for downscaling of precipitation and temperature. The future screened predictor data pertaining to RCP 8.5 of CanESM2 model were downscaled to monthly temperature and precipitation for future periods (2011-2100) using WANN models. The investigation of the future projections revealed an average increase of 17-25% in the mean annual precipitation and 20-25% average increase in the monthly mean precipitation for all the selected stations towards the end of 21st century. The monthly mean temperature also showed an increase of 2-3 °C for all the study stations towards the end of 21st century. The mean seasonal temperature of the projected period is found to be increasing for all the four seasons in most parts of the basin.

Fluctuating boundary layer on a magnetized plate

1967 ◽  
Vol 63 (2) ◽  
pp. 513-525 ◽  
Author(s):  
Sahib Singh Chawla
Keyword(s):  
Boundary Layer ◽  
Low Frequency ◽  
Surface Current ◽  
Frequency Range ◽  
Mean Flow ◽  
Wave Type ◽  
High Frequencies ◽  
Phase Lead ◽  
The Mean ◽  
The Magnetic Field

The laminar boundary layer on a magnetized plate, when the magnetic field oscillates in magnitude about a constant non-zero mean, is analysed. For low-frequency fluctuations the solution is obtained by a series expansion in terms of a frequency parameter, while for high frequencies the flow pattern is of the ‘skin-wave’ type unaffected by the mean flow. In the low-frequency range, the phase lead and the amplitude of the skin-friction oscillations increase at first and then decrease to their respective ‘skin-wave’ values. On the other hand the phase angle of the surface current decreases from 90° to 45° and its amplitude increases with frequency.

scholarly journals Effects of Tea (Camellia sinensis) Phytochemicals on the Yoghurt Cultures (Lactobacillus bulgaricus and Streptococcus thermophilus) During Development and Storage of Tea Fortified Yoghurts

2015 ◽  
Vol 4 (4) ◽  
pp. 59
Author(s):  
Simon Oduor Ochanda ◽  
John Kanyiri Wanyoko ◽  
Abdul Kiptoo Faraj ◽  
Christine Akoth Onyango ◽  
Henrik Kipngeno Ruto
Keyword(s):  
Developmental Stages ◽  
Setting Time ◽  
Streptococcus Thermophilus ◽  
Growth Patterns ◽  
Lactobacillus Bulgaricus ◽  
Mean Values ◽  
The Mean ◽  
And Storage ◽  
Mean Time ◽  
Sensory Tests

<p>Tea phytochemicals have been reported to exhibit potent antimicrobial activity. This current study reports the ability of <em>Streptococcus thermophilus</em> and <em>Lactobacillus</em> <em>bulgaricus</em> to grow, survive and multiply in the presence of tea phytochemicals during development and storage of tea fortified yoghurts. Two Kenyan tea varieties clone TRFK 6/8 (standard black quality tea) and clone TRFK 306/1 (newly developed purple leafed tea clone), were processed as aerated and non-aerated teas and used to develop tea fortified yoghurt. The teas were added at concentrations of 0, 1, 2 and 4 g in 250 mL volumes of milk (w/v) which was predetermined by sensory tests. The results showed that tea phytochemicals at the added ranges had no adverse effect on the growth of <em>Lactobacillus bulgaricus</em> and <em>Streptococcus thermophilus</em>; however, yoghurt setting time was prolonged at a mean time of 4.11, 5.22, 7.29 and 8.26 hrs respectively for tea concentrations of 0, 1, 2 and 4 g/250 mL milk. The mean microbial load for <em>Lactobacillus bulgaricus and Streptococcus thermophilus</em> in black, green and purple tea yoghurts were also inversely proportional to the concentration of the added teas. In the developmental stages of tea fortified yoghurts <em>Lactobacillus bulgaricus</em> range was 0.52-1.58 × 10<sup>7 </sup>CFU/mL while <em>Streptococcus thermophilus</em> range was 2.53-3.51 × 10<sup>9 </sup>CFU/mL, during storage the growth patterns were different between the cultures. The recorded mean values range for <em>Lactobacillus bulgaricus</em> was 2.79-4.35 × 10<sup>7 </sup>CFU/mL while <em>Streptococcus thermophilus</em> mean range was 2.57-3.47 × 10<sup>9</sup> CFU/mL Phytochemicals traced in the product had concentration values below 5 × 10<sup>2</sup><sup> </sup>µgmL<sup>-1</sup>. In conclusion, it was possible to develop probiotic tea fortified yoghurt containing tea phytochemicals with unlimited health benefits using different the different tea clones.</p>

scholarly journals Polycyclic Aromatic Hydrocarbons in PM2.5 and PM2.5–10 in Urumqi, China: Temporal Variations, Health Risk, and Sources

Atmosphere ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 412 ◽  
Author(s):  
Suwubinuer Rekefu ◽  
Dilinuer Talifu ◽  
Bo Gao ◽  
Yusan Turap ◽  
Mailikezhati Maihemuti ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Coal Combustion ◽  
Temporal Variations ◽  
Diagnostic Ratios ◽  
Positive Matrix ◽  
Increasing Trend ◽  
Polycyclic Aromatic ◽  
The Mean

PM2.5 and PM2.5–10 samples were simultaneously collected in Urumqi from January to December 2011, and 14 priority polycyclic aromatic hydrocarbons (PAHs) were determined. The mean concentrations of total PAHs in PM2.5 and PM2.5–10 were 20.90~844.22 ng m−3 and 19.65~176.5 ng m−3 respectively, with the highest in winter and the lowest in summer. Above 80% of PAHs were enriched in PM2.5, which showed remarkable seasonal variations compared to coarse particles. High molecular weight (HMW) PAHs were predominant in PM2.5 (46.61~85.13%), whereas the proportions of lower molecular weight (LMW) and HMW PAHs in PM2.5–10 showed a decreasing and an increasing trend, respectively, from spring to winter. The estimated concentrations of benzo[a]pyrene equivalent carcinogenic potency (BaPeq) in PM2.5 (10.49~84.52 ng m−3) were higher than that of in PM2.5–10 (1.15~13.33 ng m−3) except in summer. The estimated value of inhalation cancer risk in PM2.5 and PM2.5–10 were 1.63 × 10−4~7.35 × 10−3 and 9.94 × 10−5~1.16 × 10−3, respectively, far exceeding the health-based guideline level of 10−4. Diagnostic ratios and positive matrix factorization results demonstrated that PAHs in PM2.5 and PM2.5–10 were from similar sources, such as coal combustion, biomass burning, coking, and petroleum combustion, respectively. Coal combustion was the most important source for PAHs both in PM2.5 and PM2.5–10, accounting for 54.20% and 50.29%, respectively.

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