Spatiotemporal variability of E. coli concentrations in two irrigation ponds

2021 ◽  
Author(s):  
Matthew Stocker ◽  
Robert Hill ◽  
Moon Kim ◽  
Yakov Pachepsky
Keyword(s):  
Spatial Patterns ◽  
Spatiotemporal Variability ◽  
Microbial Water Quality ◽  
E Coli ◽  
Growing Seasons ◽  
The Mean ◽  
Relative Differences ◽  
Observation Times ◽  
Observation Period

<p>Escherichia coli is the most commonly assessed indicator of fecal contamination. The presence of elevated levels of E. coli is used to evaluate the microbial water quality in recreational and irrigation water sources.  E. coli concentrations are spatially and temporally variable. Monitoring of the variability inherent in water measurements can help create and implement effective monitoring designs and solutions. The objective of this work is to determine if there exist spatial patterns that are stable in time over years of observations. Two irrigation ponds in Maryland USA were monitored for three years during the growing seasons (June to August). Water samples and in situ measurements were collected in the same 47 locations biweekly for three years. The presence of stable spatial patterns was researched for relative differences between the logarithm of concentrations in specific locations and the average logarithm across the pond for each of observation times. The mean of these relative differences (MRD) over the observation period formed consistent spatial patterns. We found stable patterns of locations across the pond and found higher MRD values near the banks than the pond interiors.  MRDs computed for separate years were more variable and had amplitudes different from the overall average MRD over the three years, although the similarities between patterns across years was apparent. </p>

scholarly journals Validation of HOAPS Rain Retrievals against OceanRAIN In-Situ Measurements over the Atlantic Ocean

Atmosphere ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 15
Author(s):  
Karl Bumke ◽  
Robin Pilch Kedzierski ◽  
Marc Schröder ◽  
Christian Klepp ◽  
Karsten Fennig
Keyword(s):  
Phase Precipitation ◽  
Perfect Agreement ◽  
Precipitation Measurement ◽  
Precipitation Estimates ◽  
The Mean ◽  
Temporal And Spatial ◽  
High Precipitation ◽  
Observation Times ◽  
Spatial Threshold

The satellite-derived HOAPS (Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data) precipitation estimates have been validated against in-situ precipitation measurements from optical disdrometers, available from OceanRAIN (Ocean Rainfall And Ice-phase precipitation measurement Network) over the open-ocean by applying a statistical analysis for binary estimates. In addition to using directly collocated pairs of data, collocated data were merged within a certain temporal and spatial threshold into single events, according to the observation times. Although binary statistics do not show perfect agreement, simulations of areal estimates from the observations themselves indicate a reasonable performance of HOAPS to detect rain. However, there are deficits at low and mid-latitudes. Weaknesses also occur when analyzing the mean precipitation rates; HOAPS underperforms in the area of the intertropical convergence zone, where OceanRAIN observations show the highest mean precipitation rates. Histograms indicate that this is due to an underestimation of the frequency of moderate to high precipitation rates by HOAPS, which cannot be explained by areal averaging.

scholarly journals Characteristics of Air-Sea Fluxes Based on In Situ Observations from a Platform in the Bohai Gulf during Early Mid-August 2011

2013 ◽  
Vol 2013 ◽  
pp. 1-10
Author(s):  
Bingui Wu ◽  
Yiyang Xie ◽  
Yi Lin ◽  
Xinxin Ye ◽  
Jing Chen ◽  
...  
Keyword(s):  
Wind Waves ◽  
Characteristic Curve ◽  
Atmospheric Stability ◽  
High Water ◽  
Turbulent Fluxes ◽  
Level 3 ◽  
Eddy Covariance System ◽  
The Mean ◽  
Observation Period

An eddy covariance system and other atmospheric and oceanic parameters were measured simultaneously from a fixed Platform-A in the Bohai Gulf during early mid-August 2011. One of the main goals of the comprehensive observation was to reveal the basic meteorological and hydrological characteristics of the Bohai Gulf. The results indicated that the diurnal characteristic curve for the air temperature (AT) was steeply unimodal, while the curve of the SST was a bimodal valley type and mainly influenced by tides with its valley value corresponding to the high water level during the observation period. Southeasterly winds dominated and the wind speed was generally lower than 8 m/s, and the atmospheric stability over the Bohai Gulf was generally unstable. The wave strength levels were generally below level 3, with a greater number of swell waves than wind waves. The latter were usually associated with more momentum transport, a larger difference between AT and SST, and less heat transport. During the observational period, the mean momentum, sensible, and latent heat turbulent fluxes were 0.21, 21.6, and 27.8 W/m2, respectively. The ratio of the mean latent and sensible turbulent fluxes was about 1.3 and much lower than that in the South China Sea during the summer.

T90 as a tool for engineers: interest and limits

1997 ◽  
Vol 35 (11-12) ◽  
pp. 277-281 ◽  
Author(s):  
J. F. Guillaud ◽  
A. Derrien ◽  
M. Gourmelon ◽  
M. Pommepuy
Keyword(s):  
Water Quality ◽  
Viable Count ◽  
Mediterranean Coast ◽  
Water Protection ◽  
Bacterial Reduction ◽  
Microbial Water Quality ◽  
E Coli ◽  
Cellular Integrity ◽  
The Impact

Coastal management and water protection must provide acceptable water quality for shellfishing and tourist activities. To determine the impact of sewage on microbial water quality, engineers need to know the laws of bacterial reduction. In this study, experiments were performed with Escherichia coli in the laboratory and in situ (Atlantic and Mediterranean coast) using diffusion chambers at several depths. T90 was calculated from culturable bacterial counts over time. Establishing an abacus integrating the depth of water impacted by sewage and turbidity enabled us to calculate T90 from daily sunlight illuminations. Results obtained by cultures minimise health risks and yet viability and cellular integrity of E. coli remain, even under intense sunlight stress. When direct viable count is used to calculate a VT90, the results are dramatically higher and show how necessary – and difficult – it is to develop a concept which takes account of better understanding of sanitary risks in impact studies.

scholarly journals Temporal Stability ofEscherichia coliConcentrations in Waters of Two Irrigation Ponds in Maryland

2017 ◽  
Vol 84 (3) ◽  
Author(s):  
Yakov Pachepsky ◽  
Rachel Kierzewski ◽  
Matthew Stocker ◽  
Kevin Sellner ◽  
Walter Mulbry ◽  
...  
Keyword(s):  
Water Quality ◽  
Irrigation Water ◽  
Temporal Stability ◽  
Water Quality Monitoring ◽  
Water Sources ◽  
Microbial Water Quality ◽  
Content Type ◽  
Environmental Covariates ◽  
E Coli ◽  
Relative Differences

ABSTRACTFecal contamination of water sources is an important water quality issue for agricultural irrigation ponds.Escherichia coliconcentrations are commonly used to evaluate recreational and irrigation water quality. We hypothesized that there may exist temporally stable spatial patterns ofE. coliconcentrations across ponds, meaning that some areas mostly have higher and other areas mostly lower than average concentrations ofE. coli. To test this hypothesis, we sampled two irrigation ponds in Maryland at nodes of spatial grids biweekly during the summer of 2016. Environmental covariates—temperature, turbidity, conductivity, pH, dissolved oxygen, chlorophylla, and nutrients—were measured in conjunction withE. coliconcentrations. Temporal stability was assessed using mean relative differences between measurements in each location and averaged measurements across ponds. Temporally stable spatial patterns ofE. coliconcentrations and the majority of environmental covariates were expressed for both ponds. In the pond interior, larger relative mean differences in chlorophyllacorresponded to smaller mean relative differences inE. coliconcentrations, with a Spearman's rank correlation coefficient of 0.819. Turbidity and ammonium concentrations were the two other environmental covariates with the largest positive correlations between their location ranks and theE. coliconcentration location ranks. Tenfold differences were found between geometric meanE. coliconcentrations in locations that were consistently high or consistently low. The existence of temporally stable patterns ofE. coliconcentrations can affect the results of microbial water quality assessment in ponds and should be accounted for in microbial water quality monitoring design.IMPORTANCEThe microbial quality of water in irrigation water sources must be assessed to prevent the spread of microbes that can cause disease in humans because of produce consumption. The microbial quality of irrigation water is evaluated based on concentrations ofEscherichia colias the indicator organism. Given the high spatial and temporal variability ofE. coliconcentrations in irrigation water sources, recommendations are needed on where and when samples of water have to be taken for microbial analysis. This work demonstrates the presence of a temporally stable spatial pattern in the distributions ofE. coliconcentrations across irrigation ponds. The ponds studied had zones whereE. coliconcentrations were mostly higher than average and zones where the concentrations were mostly lower than average over the entire observation period, covering the season when water was used for irrigation. Accounting for the existence of such zones will improve the design and implementation of microbial water quality monitoring.

scholarly journals Spatiotemporal variability of soil-water characteristic curve model parameters of Lanzhou collapsible loess

2021 ◽  
Author(s):  
Wenju Zhao ◽  
Yuhang Liu ◽  
Jiazhen Hu ◽  
Zongli Li
Keyword(s):  
Soil Water ◽  
Characteristic Curve ◽  
Temporal Stability ◽  
Spatiotemporal Variability ◽  
Model Parameters ◽  
Measuring Point ◽  
Collapsible Loess ◽  
Comprehensive Comparison ◽  
The Mean ◽  
Relative Differences

Abstract The spatiotemporal variation of the model parameters of the soil-water characteristic curve (SWCC) reflect the soil water holding capacity and soil pore distribution state. It is an integral part of interdisciplinary disciplines such as soil hydrodynamics and ecohydrology. The authors selected the optimal SWCC model for the Lanzhou collapsible loess, used classical statistics and geostatistics methods studied the spatiotemporal variability of the SWCC model parameters, and used the comprehensive comparison of the mean relative differences (MRD), standard deviations (SDRD) and an index of temporal stability (ITS) determined the representativeness measuring point. The results showed that the SWCC parameters α was medium variability in the 0–30 cm soil layer, n and θs were of low variability, the spatial distribution of the parameters of different soil layers was consistent. Migration direction prediction of θs was very similar in each layer, α, n and θs were all strongly significantly correlated positively. Moreover, the determination coefficient of representative measuring point 16 had the highest prediction accuracy for the measured values of SWCC. The results of this paper can be used as a simple method to predict SWCC and provide theoretical guidance for soil water management and soil collapse erosion monitoring in collapsible loess area. HIGHLIGHT Presented a study of the temporal stability and variability of SWCC in the Lanzhou collapsible loess, using the comprehensive comparison of the Mean relative differences (MRD), standard deviations (SDRD) and an index of temporal stability (ITS), and determined the representativeness measuring point.

Hydrology and flood probability of the monsoon-dominated Chindwin River in northern Myanmar

2014 ◽  
Vol 6 (1) ◽  
pp. 144-160 ◽  
Author(s):  
Zaw Zaw Latt ◽  
Hartmut Wittenberg
Keyword(s):  
Southwest Monsoon ◽  
Mean Value ◽  
Spatial And Temporal Variation ◽  
Mean Values ◽  
Flood Probability ◽  
The Mean ◽  
Flood Quantiles ◽  
High Flood ◽  
Relative Differences ◽  
Observation Period

As the third largest river of Myanmar, the Chindwin River has great importance as a water resource and transport artery. At 113,800 km2 the basin is comparable in size to the Elbe basin in Europe, although with higher rainfall and runoff. During the southwest monsoon high rainfall intensities with spatial and temporal variation causing severe floods are threatening the region. The study aims to analyze the hydrologic aspects of monsoon floods using statistical and frequency analysis. Flood responses vary due to the complex topography and rainfall distribution over the catchment. Time series of annual maximum floods shows no trend of the mean value. The deviation of annual maxima from the respective mean values, however, has increased significantly in recent decades. Flood quantiles are determined for return periods of 2 to 1,000 years using the data covering the period 1966 to 2011. Flood probability analysis shows that the upper and middle parts of the basin have particularly high flood risks. To analyze the change in flood values, the relative differences of flood quantiles in two time phases, 1966–1990 and 1991–2011, with respect to the entire observation period are compared. The expected floods of the latter period are the highest.

HRA Model for Hypercholesterolemia Based on a Longitudinal Health Database

1998 ◽  
Vol 37 (02) ◽  
pp. 130-133
Author(s):  
T. Kishimoto ◽  
Y. Iida ◽  
K. Yoshida ◽  
M. Miyakawa ◽  
H. Sugimori ◽  
...  
Keyword(s):  
Total Cholesterol ◽  
Proportional Hazards ◽  
Proportional Hazards Model ◽  
Model Analysis ◽  
Serum Total Cholesterol ◽  
Hazards Model ◽  
The Mean ◽  
Health Database ◽  
Observation Period

AbstractTo evaluate the risk factors for hypercholesterolemia, we examined 4,371 subjects (3,207 males and 1,164 females) who received medical checkups more than twice at an AMHTS in Tokyo during the period from 1976 through 1991; and whose serum total cholesterol was under 250 mg/dl. The mean follow-up duration was 6.6 years. A self-registering questionnaire was administered at the time of the health checkup. The endpoint of this study was the onset of hypercholesterolemia when the level of serum total cholesterol was 250 mg/dl and over. We compared two prognosis groups (normal and hypercholesterol) in terms of age, examination findings and lifestyle. After assessing each variable, we employed Cox's proportional hazards model analysis to determine the factors related to the occurrence of hypercholesterolemia. According to proportional hazards model analysis, total cholesterol, triglyceride and smoking at the beginning, and hypertension during the observation period were selected in males; and total cholesterol at the beginning and age were selected in females to determine the factors related to the occurrence of hypercholesterolemia.

Pharmacokinetics and Tolerability of Factor XIII Concentrates Prepared from Human Placenta or Plasma: a Crossover Randomised Study

1995 ◽  
Vol 74 (02) ◽  
pp. 622-625 ◽  
Author(s):  
H H Brackmann ◽  
R Egbring ◽  
A Ferster ◽  
P Fondu ◽  
J M Girardel ◽  
...  
Keyword(s):  
Factor Xiii ◽  
Bleeding Events ◽  
Serious Adverse Events ◽  
Double Blind ◽  
Randomised Study ◽  
The Mean ◽  
Blind Crossover Study ◽  
Double Blind Crossover Study ◽  
Fxiii Activity ◽  
Observation Period

SummaryThe pharmacokinetics and tolerability of factor XIII (FXIII) from plasma were compared with those of FXIII from placenta in a randomised, double-blind, crossover study involving 13 patients with congenital FXIII deficiency. Both FXIII activity and FXIII antigen were monitored. No difference was seen in the mean half-lives of the two preparations (9.3 days and 9.1 days for plasma and placenta FXIII activity, respectively). Response was similar for both preparations, but was slightly greater for FXIII from plasma.Similar results were found for recovery (65% vs 60%). The area under the data completed by extrapolation was significantly higher for FXIII from plasma. No differences between preparations in terms of efficacy or tolerability were observed. It can be concluded that treatment with FXIII concentrate from plasma is as efficient as with FXIII concentrate from placenta in terms of recovery and half-life. Both preparations were equivalent in terms of safety during the observation period. With the administration of monthly injections of approximately 30 U/kg serious bleeding events were prevented and no other serious adverse events occurred.

Novel Formulation Development and Evaluation of Nanoparticles Based in Situ Gelling System for The Ophthalmic Delivery of Ciprofloxacin Hydrochloride

2015 ◽  
Vol 5 (4) ◽  
Author(s):  
Kranti Singh ◽  
Surajpal Verma ◽  
Shyam Prasad ◽  
Indu Bala
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Drug Loading ◽  
In Vitro Release ◽  
Formulation Development ◽  
Ciprofloxacin Hydrochloride ◽  
Potential Value ◽  
The Mean ◽  
In Situ Gelling

Ciprofloxacin hydrochloride loaded Eudragit RS100 nanoparticles were prepared by using w/o/w emulsification (multiple emulsification) solvent evaporation followed by drying of nanoparticles at 50°C. The nanoparticles were further incorporated into the pH-triggered in situ gel forming system which was prepared using Carbopol 940 in combination with HPMC as viscosifying agent. The developed nanoparticles was evaluated for particle size, zeta potential value and loading efficiency; nanoparticle incorporated in situ gelling system was evaluated for pH, clarity, gelling strength, rheological studies, in-vitro release studies and ex-vivo precorneal permeation studies. The nanopaticle showed the mean particle size varying between 263.5nm - 325.9 nm with the mean zeta potential value of -5.91 mV to -8.13 mV and drug loading capacity varied individually between 72.50% to 98.70% w/w. The formulation was clear with no suspended particles, showed good gelling properties. The gelling was quick and remained for longer time period. The developed formulation was therapeutically efficacious, stable and non-irritant. It provided the sustained release of drug over a period of 8-10 hours.

Optics-Free Visualization of Proteins in Single Cells by Time of Flight-Secondary Ion Mass Spectrometry Coupled with Genetically Encoded Chemical Tags

2020 ◽  
Author(s):  
Feifei Jia ◽  
Jie Wang ◽  
Yanyan Zhang ◽  
Qun Luo ◽  
Luyu Qi ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Secondary Ion Mass Spectrometry ◽  
Single Cells ◽  
Time Of Flight ◽  
E Coli ◽  
Tof Sims ◽  
Ion Mass Spectrometry ◽  
Chemical Tags ◽  
Secondary Ion

<p></p><p><i>In situ</i> visualization of proteins of interest at single cell level is attractive in cell biology, molecular biology and biomedicine, which usually involves photon, electron or X-ray based imaging methods. Herein, we report an optics-free strategy that images a specific protein in single cells by time of flight-secondary ion mass spectrometry (ToF-SIMS) following genetic incorporation of fluorine-containing unnatural amino acids as a chemical tag into the protein via genetic code expansion technique. The method was developed and validated by imaging GFP in E. coli and human HeLa cancer cells, and then utilized to visualize the distribution of chemotaxis protein CheA in E. coli cells and the interaction between high mobility group box 1 protein and cisplatin damaged DNA in HeLa cells. The present work highlights the power of ToF-SIMS imaging combined with genetically encoded chemical tags for <i>in situ </i>visualization of proteins of interest as well as the interactions between proteins and drugs or drug damaged DNA in single cells.</p><p></p>

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