Diurnal Changes In Concentrations Research Articles

Particle size distribution shift and diurnal concentration changes of environmental DNA caused by fish spawning behaviour

Particle size distribution shift and diurnal concentration changes of environmental DNA caused by fish spawning behaviour

Analysis of the Diurnal Changes in the Water-Soluble Ion Concentration in Wuhan between 2016 and 2019

This study uses online monitoring data from the Hubei Environmental Monitoring Center’s Atmospheric Compound Pollution Automatic Monitoring Station from 2016 to 2019 to analyze the diurnal changes in the concentration of water-soluble ions in particulate matter in Wuhan. During the study period, the concentrations of SO2, NO3−, and SO42− changed significantly, while those of NH4+, NH3, and Ca2+ exhibited minimal differences. SO2 and NO3− showed an annually increasing trend, while NH4+ and SO42− exhibited an annually decreasing trend. The ion concentration was generally higher in the winter and spring and lower in the summer and autumn. The concentration of water-soluble ions was generally higher during the day than at night. However, the “weekend effect” on the change in ion concentrations was substantial and higher during the day than at night. This effect was the strongest for NO3− and the weakest for NH3. These changes in the weekend effect of water-soluble ions in particulate matter clearly revealed the impact of periodic human activities on atmospheric pollution. Taken together, the results of this novel study reveal the diurnal pollution characteristics and “weekend effect” of water-soluble ions with high concentrations in atmospheric aerosols in Wuhan over a four-year period, thus providing relevant insights for Wuhan’s atmospheric mitigation plan.

Temporal variations of the conduction current density during fair weather days in Israel

Ground-based measurements of the atmospheric conduction current density were conducted on Mount Hermon in northern Israel (33°18′N 35°47.2′E, 2050 m a.s.l). The aim was to measure the conduction current diurnal behavior during days that are defined meteorologically as fair weather days. Results from 86 selected fair weather days show an average value of 0.9 pA/m2 downward, and a double oscillation behavior of the conduction current density with two maxima – a morning peak due to local effect and an evening peak due to global effect, with lower values in between. Fourier transform analysis applied to the continuous data shows the two maxima peaks under the daily background level. The conduction current density, together with the fair weather vertical electric field was used to calculate the fair weather mean conductivity behavior (based on Ohm's law). The conductivity shows minimum values during local noon hours when the station is assumed to be within the boundary layer and high conductivity values during the night hours when the station is above the boundary layer. This is likely due to the respective diurnal changes in concentrations of aerosol particles. A WRF simulation of a single fair weather day was conducted in order to determine the meteorological regime and the boundary layer height and is presented to support the hypothesis that conductivity values depend, at least in part, on the height of the boundary layer relative to the station.

Transcription factor sensor system for parallel quantification of metabolites on-chip.

Steadily growing demands for identification and quantification of cellular metabolites in higher throughput have brought a need for new analytical technologies. Here, we developed a synthetic biological sensor system for quantifying metabolites from biological cell samples. For this, bacterial transcription factors were exploited, which bind to or dissociate from regulatory DNA elements in response to physiological changes in the cellular metabolite concentration range. Representatively, the bacterial pyruvate dehydrogenase (PdhR), trehalose (TreR), and l-arginine (ArgR) repressor proteins were functionalized to detect pyruvate, trehalose-6-phosphate (T6P), and arginine concentration in solution. For each transcription factor the mutual binding behavior between metabolite and DNA, their working range, and othogonality were determined. High-throughput, parallel processing, and automation were achieved through integration of the metabolic sensor system on a microfluidic large-scale integration (mLSI) chip platform. To demonstrate the functionality of the integrated metabolic sensor system, we measured diurnal concentration changes of pyruvate and the plant signaling molecule T6P within cell etxracts of Arabidopsis thaliana rosettes. The transcription factor sensor system is of generic nature and extendable on the microfluidic chip.

Diurnal Changes in Amino Acid Concentrations in Riesling and Chardonnay Grape Juices and a Possible Role of Sunlight

Diurnal changes in the concentrations of amino acids in grape juice (Vitis vinifera L.) were investigated during mid to late ripening over three consecutive years. To avoid the effect of harvest shock, samples were prepared within 15 min after grape berry picking. Changes in the amino acid concentrations of juices were classified into three patterns. The concentrations of aspartic acid (Asp) and glutamic acid (Glu) decreased during the morning and gradually increased at night. The alanine (Ala) concentration increased during the morning and decreased at night. The amino acid peak times were 0600 to 0900 hr for Asp, 0600 to 0700 hr for Glu, and 1300 to 1900 hr for Ala for Riesling harvested from 31 Aug to 1 Sep 2010. Some of the other amino acids, such as phenylalanine, serine, proline, and threonine showed minimal or no diurnal changes in concentration. Yeast assimilable nitrogen (YAN) showed minimal daily changes. During cloudy days, these diurnal changes diminished. When grape clusters were shaded with aluminum foil, the patterns of amino acid concentrations did not change, with some exceptions. Photosynthesis is proposed as the main contributor to these changes, since minimal changes were observed under cloud cover. Moreover, leaf rather than berry photosynthesis is likely an important factor in the composition of berry amino acids.

Long-term measurements of CO, NO, NO 2, benzene, toluene and PM 10 at a motorway location in an Austrian valley

Continuous measurements of CO, NO, NO 2, PM 10, benzene and toluene were conducted over a one-year period at a motorway location in the alpine Inn valley. Diurnal changes in concentrations of detected compounds were observed to vary according to traffic type and frequency, and meteorological conditions of the valley atmosphere, which were both additionally recorded at this location. Seasonal variations were also clearly seen, with lowest levels of compound abundances present in summer and highest levels in winter. Annual mean abundances of compounds were assessed with respect to guideline limits and it was found that NO 2 and PM 10 exceeded their legislation thresholds. This investigation also included the first continuous year-long measurements of benzene at this location, yielding an annual mean volume mixing ratio of 0.6 ppbV, which is well within the EU guideline limit of 1.5 ppbV. Additionally, benzene abundances were found to correlate well with CO concentrations. A significant correlation was also found between toluene and benzene. However, the ratio toluene:benzene shifted from about 2:1 in summer to approximately 1:1 in winter. This may be explained by a strong evaporative and therefore temperature dependent toluene source, while benzene concentrations mainly result from non-ambient temperature dependent exhaust pipe emissions. This seasonal variation must be taken into account whenever this ratio is used to determine the chemical age of an air mass.

Regional carbon fluxes and the effect of topography on the variability of atmospheric CO2

Using a mesoscale atmospheric circulation model, it is shown that relatively modest topography height differences of ∼500 m over 200 km near Zotino (60°N, 89°E) in central Siberia may generate horizontal gradients in CO2 concentration in the order of 30 ppm. In a case study for 15 and 16 July 1996, when Lloyd et al. (2001) conducted a convective boundary layer budget experiment in the area, we show that advection of these gradients disturbs the relation between diurnal concentration changes in the boundary layer and the surface fluxes. This demonstrates that mesoscale atmospheric heterogeneity may have severe impact on the applicability of methods to derive the regional‐scale fluxes from CO2 concentrations measurements, such as the convective boundary layer budget method or inverse modeling. It is shown that similar mesoscale gradients are likely to occur at many long‐term observation stations and tall towers. We use the modeled concentration fields to quantify the horizontal and vertical variability of carbon dioxide in the atmosphere. In future observation campaigns, mesoscale processes may be best accounted for by measuring horizontal variability over a few hundred kilometers and by attempting to quantify the representation errors as a function of mesoscale conditions.

London methane emissions: Use of diurnal changes in concentration and δ13C to identify urban sources and verify inventories

Diurnal air sampling campaigns at the Royal Holloway site on the western fringe of London, United Kingdom, have been used to: (1) test the validity of using carbon isotopes to identify local methane sources, (2) determine the isotopic signature of overnight build‐up profiles, in order to estimate regional emissions, and (3) verify statistical estimates of emissions. For CH4 an overall London δ13C source mix of −48.7±0.3‰ has been calculated from gradual overnight methane buildup in air masses moving from the east. Isotopic characterization of specific methane peaks shows them to be derived either from natural gas leaks (δ13C −33‰ to −35‰) or waste treatment emissions (δ13C −51‰ to −53‰). While landfill/waste emissions dominate, gas distribution losses represent ∼20% of the bulk local source. Various estimates of total London methane emissions for 1996 were made, using diurnal excess, isotopic data and trajectory movement across London to the sampling station. The results are in the range 240–312 kt/yr, higher than the London estimate in current U.K. greenhouse gas inventory assessments of emissions but within error of earlier statistical estimates for 1996. The results show that it is possible to use atmospheric concentration, isotopic, and meteorological data together to verify statistical estimates testing them for internal consistency and using better constrained data to calibrate more poorly known source fluxes. Importantly, atmospheric data can place constraints on poorly constrained landfill emission estimates for the region. These quasi‐independent methods for verification of greenhouse gas emissions will contribute in assessing compliance with the Kyoto agreement.

Seasonal and Diurnal Variation of Airborne Basidiomycete Spore Concentrations in Mexico City

Abstract Seasonal and diurnal changes in concentrations of airborne basidiomycete spores (basidiospores, rusts, smuts) were studied, using Burkard volumetric spore traps, in two areas of Mexico City with different degrees of urbanization and related to changes in climatic variables through 1991. Basidiomycete spores formed a large component of the total airborne fungal spore load in the atmosphere of Mexico City. They were the second most abundant spore type after Deuteromycotina (Hyphomycetes), forming 32% of the total fungal spores trapped in an urban-residential area and 28% in an urban-commercial area. The most abundant basidiomycete spores were basidiospores although smut-type spores were trapped on more days than basidiospores and rusts on fewer. Basidiospores occurred in concentrations up to 2,000 spores m-3 in the urban-residential area. Basidiospores showed a marked seasonal distribution, especially in the southern area, with their greatest abundance during the wet season. The correlation coeffic...

Environmental conditions affecting concentrations of He, CO 2, O 2 and N 2 in soil gases

The measurement of concentrations of volatile species in soil gases has potential for use in geochemical exploration for concealed ore deposits and for monitoring of subsurface contaminants. However, the interpretation of anomalies in surficial gases can be difficult because soil-gas concentrations are dependent on both meteorological and environmental conditions. For this study, concentrations of He, CO 2, O 2 and N 2 and meteorological conditions were monitored for 10–14 months at eight nonmineralized sites in both humid and dry environments. Gases were collected at 0.6–0.7-m depth at seven sites. At one site, gases were collected from 0.3-, 0.6-, 1.2-, and 2.0-m depths; diurnal monitoring studies were conducted at this site also. Rain and snowfall, soil and air temperatures, barometric pressure, and relative humidity were monitored at all the sites. The sand, silt and clay content, and the organic carbon content of surficial soil were measured at each site. Meteorological conditions generally affected He and CO 2 concentrations in the same way at all the sites; however, these effects were modified by local environmental conditions. Both seasonal and diurnal concentration changes occurred. The most important seasonal concentration changes were related to rain and snowfall and soil and air temperatures. Seasonal changes tended to be larger then the diurnal changes, but both could be related to the same processes. Local conditions of soil type and organic content affected the amount of pore space and moisture present in the soil and therefore the soil-gas concentrations.

A method for assessing diurnal changes in concentration of sugars and malate in the pericarp of growing tomato fruit

The content of hexose sugars and malate in growing tomato fruit (attached to the parent plant) have been measured by microassay of extracts from small discs cut from the pericarp. The removal of pericarp discs did not significantly affect fruit growth rate and provided sufficient tissue to analyse accurately the contents of hexose and malate. Several discs could be removed from the same fruit during 24 h, allowing an assessment of any diurnal variation in these constituents during changes of temperature, light and growth rate in fruit grown in glasshouse conditions and in artificially lit controlled environments. Data are presented to validate the microassay and sampling methods, and examples of diurnal fluctuations in sugars and malate are presented.

Diurnal Variation of Serum Progesterone, but Not Relaxin, Prolactin, or Estradiol-17β in The Pregnant Bitch*

The concentrations of progesterone (P), relaxin (Rlx), estradiol (E2) and PRL were measured by specific RIAs in serum samples collected twice daily at 8:00 am and 3:00 pm at weekly intervals after mating and until whelping in five Labrador Retriever bitches. From weeks 3 to 6 of pregnancy, P exhibited a conspicuous and statistically significant diurnal pattern (P less than 0.05), its serum concentration being approximately twice as high at 8:00 am as at 3:00 pm. A similar but nonsignificant trend was observed weeks 2, 7, and 8, and the overall ratio of the am/pm P concentrations was 2.4 +/- 0.28 (P less than 0.001). Rlx, E2, and PRL did not show a diurnal pattern at any time during pregnancy. The glandular sources and regulation of secretion of Rlx were further investigated. Rlx bioactivity was detected in canine placentas and ovaries, providing supportive evidence that these organs may be a dual source of the hormone in canine pregnancy. Injection of ovine PRL in three pseudopregnant bitches significantly increased serum P concentration as compared with seven untreated pseudopregnant controls, but Rlx was not detectable in serum before, during or after PRL treatment. The data support the view that Rlx and P are independently regulated in the bitch; PRL may be a regulator of P, but not of Rlx secretion. However, as PRL showed no diurnal changes in concentration, it does not appear to be directly responsible for the diurnal pattern exhibited by P.

Occurrence and diurnal population fluctuations of the ruminal protozoan Microcetus lappus

A series of experiments with bison and cattle were conducted to obtain information on the relatively uncommon ruminal protozoan Microcetus lappus. Although M. lappus is a holotrich, diurnal changes in concentrations indicate that it follows a cycle unlike most other holotrichs, decreasing shortly after feed is offered and then gradually increasing over time. Concentrations of M. lappus varied widely among animals, exceeding 50% of the total protozoan population in some cattle. In bison, Microcetus concentrations averaged 2% of the protozoan population. Dietary protein and energy levels apparently did not influence Microcetus numbers. The highest concentrations of M. lappus were found in the reticulum, whereas the lowest numbers occurred in the mid-dorsal sac.

Chemical Volatilization in Nearly Dry Soils under Non‐Isothermal Conditions

AbstractA theoretical investigation of the volatilization of chemical contaminants in the top layer of a nearly dry soil column under nonisothermal conditions is presented in this paper. The proposed one‐dimensional model considers the effect of natural convection, and the variations of diffusivity and vapor phase adsorption with temperature on contaminant flux across the soil‐air interface. The study has shown that natural convection effects are small. Diurnal temperature changes were found to lead to fluctuations in the concentration profiles and the volatilization flux due to alternating adsorption/desorption processes in the soil. These diurnal changes in concentration cannot be determined from isothermal calculations. Finally, it is suggested that a simple linear isothermal diffusion model may be adequate for describing the chemical concentration profiles at times that are sufficiently long past the initial soil contamination event.

Diurnal changes in leaf chemical constituents and (14)C partitioning in cottonwood.

Diurnal changes in concentrations of leaf chemical fractions and partitioning of photosynthetically fixed (14)C within the plant and among chemical fractions were studied in rapidly growing cottonwood (Populus deltoides Bartr. ex Marsh.) seedlings. During the light period, leaf weight (mg cm(-2)) increased by about 25% primarily as a result of the accumulation of starch and sucrose, and to a lesser extent because of an increase in the content of amino acids and the chloroform fraction (pigments plus lipids). In contrast, reducing sugars and organic acids decreased in concentration. The partitioning of (14)C within the plant also changed during the light period. Acropetal transport to developing leaves and stem decreased from 81 to 55% of the total (14)C translocated from a source leaf in 4 hours, whereas basipetal transport to stem and roots increased from 13 to 37%. Although assimilation rate ((14)C fixed in 0.5 h) remained constant during the light period, the percentage of fixed (14)C translocated out of the source leaf in 4 h decreased from 27 to 9%. This change in transport rate of recently fixed (14)C was caused by a shift in (14)C partitioning from transport sucrose to storage starch. During the light period, the incorporation ratio ((14)C-sugar/(14)C-starch) decreased from 40 at 0700 h to 2 at 1900 h. The partitioning of carbon to different chemical fractions within the source leaf and the interactions or feedback between different sinks and the source leaf have a major influence on plant growth and development. Control of this carbon partitioning is located in both source and sink leaves.

Biochemical and histochemical investigation of diurnal variation in cAMP concentration and adenylate cyclase activity in white dutch clover

Diurnal changes in the concentration of cAMP in white clover were investigated biochemically and histochemically. Biochemical assays showed that a) the concentration of cAMP in healthy leaves was consistently higher than in CYMV-diseased leaves under the same light condition and b) the concentration of cAMP in clover leaves exhibited a diurnal cycle. The diurnal changes in cAMP concentration were present in both healthy and CYMV-diseased clover leaves. Histochemical localization tests indicated that the adenylate cyclase activity could be semi quantilated as more dense reaction products were present in the membrane systems of healthy than CYMV-diseased leaves. The histochemical results were consistent with the biochemical data.

Diurnal changes in concentration of rumen ciliates and in occurrence of dividing forms in water buffalo (Bubalus bubalus) fed once daily

When buffalo were fed once daily, significant diurnal variations in concentration of rumen ciliates and occurrence of dividing protozoa were found. Differences in proportions of dividing Entodinium- and Diplodinium-type ciliates were also observed. Results obtained suggest that the range of diurnal fluctuations in rumen protozoa concentration may be related to the percentage of dividing cells in populaitons of these organisms.

Nucleotide and Amino Acid Rhythms in the Chick under Temperature Stress

EARLIER studies from these laboratories (Squibb, 1964, 1968; Squibb et al., 1968) demonstrated that nucleic and free amino acids have significant within-day oscillations in various avian tissues. Other investigators have observed similar diurnal changes in concentrations and total quantities of some of these cellular components in tissues of other species (Horvath, 1963; Rapoport et al., 1966; Beisel, 1968; Gubin et al., 1968; Feigin et al., 1967). Since the chick is a rapidly growing animal, levels of nucleic and free amino acids may be considered a reflection of the anabolic phase of protein metabolism in this model and as such will be highly sensitive to stress.Constant temperature environments are often used to evaluate the effect of heat stress in man and animals in spite of the fact that under normal conditions such environments are non-existent. It has been postulated (Squibb et al., 1959) that temperature stress is related to the…