Effect Of Sampling Location Research Articles

Effects of Variation in Tamarix chinensis Plantations on Soil Microbial Community Composition in the Middle Yellow River Floodplain

Floodplains have important ecological and hydrological functions in terrestrial ecosystems, experience severe soil erosion, and are vulnerable to losing soil fertility. Tamarix chinensis Lour. plantation is the main vegetation restoration measure for maintaining soil quality in floodplains. Soil microorganisms are essential for driving biogeochemical cycling processes. However, the effects of sampling location and shrub patch size on soil microbial community composition remain unclear. In this study, we characterized changes in microbial structure, as well as the factors driving them, in inside- and outside-canopy soils of three patch sizes (small, medium, large) of T. chinensis plants in the middle Yellow River floodplain. Compared with the outside-canopy soils, inside-canopy had higher microbial phospholipid fatty acids (PLFAs), including fungi, bacteria, Gram-positive bacteria (GP), Gram-negative bacteria (GN), and arbuscular mycorrhizal fungi. The ratio of fungi to bacteria and GP to GN gradually decreased as shrub patch size increased. Differences between inside-canopy and outside-canopy soils in soil nutrients (organic matter, total nitrogen, and available phosphorus) and soil salt content increased by 59.73%, 40.75%, 34.41%, and 110.08% from small to large shrub patch size. Changes in microbial community composition were mainly driven by variation in soil organic matter, which accounted for 61.90% of the variation in inside-canopy soils. Resource islands could alter microbial community structure, and this effect was stronger when shrub patch size was large. The results indicated that T. chinensis plantations enhanced the soil nutrient contents (organic matter, total nitrogen, and available phosphorus) and elevated soil microbial biomass and changed microbial community composition; T. chinensis plantations might thus provide a suitable approach for restoring degraded floodplain ecosystems.

Development of a reproducible method for monitoring SARS-CoV-2 in wastewater

Monitoring the genetic signal of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) through RNA titers in wastewater has emerged as a promising strategy for tracking community-scale prevalence of coronavirus disease 2019 (COVID-19). Although many studies of SARS-CoV-2 in wastewater have been conducted around the world, a uniform procedure for concentrating the virus in wastewater is lacking. The goal of this study was to comprehensively evaluate how different methods for concentrating the suspended solids in wastewater affect the associated SARS-CoV-2 RNA signal and the time required for processing samples for wastewater-based epidemiology efforts. We additionally consider the effects of sampling location in the wastewater treatment train (i.e., following preliminary or primary treatment), pasteurization, and RNA extraction method. Comparison of the liquid phase to suspended solids obtained via centrifugation or vacuum filtration suggests that the RNA signal of SARS-CoV-2 preferentially occurs in the solids. Therefore, we assert that the recovery of SARS-CoV-2 from wastewater should focus on suspended solids. Our data indicate that the measured SARS-CoV-2 signal is higher among samples taken from the primary clarifier effluent, as opposed to those taken after preliminary treatment. Additionally, we provide evidence that sample pasteurization at 60 °C for 90 min reduces the SARS-CoV-2 signal by approximately 50-55%. Finally, the results indicate that a magnetic bead approach to RNA extraction leads to a higher SARS-CoV-2 signal than does a silica membrane approach.

Experimental Investigation of PolyJet 3D printing: Effects of Sample Location and Volume on Power Consumption

This paper reports an experimental study on power consumption of PolyJet 3D printing. Controllable variables studied are location of samples on the build platform and volume of printed samples. The measured output is “Power Efficiency”: electrical power consumed per unit volume (cubic millimeter) of printed samples. Power Efficiency values are determined by dividing the product of consumed wattage and total print time by total volume of samples. Samples of different volumes are placed at different locations on the build platform. The results show that Power Efficiency is higher when samples are arranged along the X axis than when they are arranged along the Y axis.

Fatigue behavior of a Ti-based metallic glass: Effect of sampling location in association with free volume

The large scatter of fatigue property severely hinders the application of metallic glasses (MGs). The sampling location may be one important reason for the fatigue scatter, however the related studies are few. Here we confirmed that, the fatigue property and mechanism of a Ti-based MG were influenced by the sampling location from casting MG plate. The differential scanning calorimetry (DSC) result indicates that the free volume contents decrease from outside to inside along the thickness direction of casting plate, which is probably due to varying cooling rates in this direction during solidification. It is found that the shear-band features after fatigue fracture depend on the sampling location, that is, for the specimens containing smaller near-surface volume, the small amount of the initial free volume contents and increased free volume contents induced by cyclic loading suppress the formation of shear band. The fatigue endurance limit, fatigue ratio and fatigue life of the specimens containing smaller near-surface volume are obviously higher. The superior fatigue property can be well explained by the shear band-mediated fatigue cracking mechanism. These results enhance the understanding on the relation between the free volume, shear band and fatigue property under cyclic loading and provide the instruction how to regulate the fatigue resistance of MG by controlling where the specimens are cut from casting MG plates based on the microstructural state.

Geographical variation in total phenolics, flavonoids and antioxidant activities of Eucalyptus camaldulensis leaves in Burkina Faso

This study aimed to elucidate the effect of sampling location of Eucalyptus camaldulensis leaves on antioxidant activity, total phenolic content (TPC) and total flavonoid content (TFC). Leaves of E. camaldulensis collected at three different locations in Burkina Faso (north, central, south-west) were subjected to hydrodistillation to obtain a water extract and subsequent ethanol extraction of the solid residue. The extracts were analysed for antioxidant activity using 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging, TPC, TFC and high-performance thin layer chromatography (HPTLC) fingerprint. TPC were higher in water extracts and presented considerable variation from 129±9 to 266±4 milligram Gallic Acid Equivalent per gram of extract (mg GAE/g) with the highest value 266±4 mg GAE/g at the south-west site. This aqueous extract also showed high antioxidant activity with EC50 8.3 µg/mL. Furthermore, HPTLC fingerprint of the extracts showed both band intensity and size differences. For TFC, we found a slight differences within both water and ethanolic extracts with the highest value of 38.3 ±4.2 mg QE/g for the south-west ethanolic extract. The noticeable impact of climate on chemical variability of E. camaldulensis leaves needs to be taken into consideration for any further applications based on TPC biological activity of the extracts. Key words: Eucalyptus camaldulensis, total phenolic content, total flavonoid content, antioxidant activity, sample location, chemical variation.

A practical method for assessing infectious laryngotracheitis vaccine take in broilers following mass administration in water: Spatial and temporal variation in viral genome content of poultry dust after vaccination

Infectious laryngotracheitis is an important disease of chickens caused by infectious laryngotracheitis virus (ILTV). Outbreaks commonly occur in meat chicken flocks and mass vaccination with live attenuated vaccines, usually in water, is used to control the disease in these populations. Vaccination with live virus via water and nipple drinkers requires stringent adherence to protocols to ensure success, but vaccine administration monitoring is not currently assessed due to a lack of economically viable methods. Vaccinal ILTV has been shown to be detectable in dust in experimental studies and has potential as a method of assessing vaccination success. However, the pattern of vaccinal ILTV detection in dust following vaccination under commercial conditions has not been defined. We report the longitudinal profile of ILTV genome copies (GC) in poultry house dust collected on settle plates following vaccination of 8 flocks of commercial meat chickens on four farms. ILTV GC was enumerated using quantitative real-time polymerase chain reaction (qPCR). There was considerable variation between flocks in the levels of ILTV GC detected post vaccination and this variation was significantly associated with vaccine take measured in individual birds in a companion study. There was no effect of sampling location on ILTV GC in dust but the amount of dust collected was greater in locations closer to the exhaust fans in artificially ventilated houses. Results indicate that measurement of ILTV GC in single or pooled dust samples at 7–8 days post vaccination enables detection of poor vaccine takes and provides a practical means of monitoring ILT vaccination.

The Effects of Sampling Location and Predictor Point Estimate Certainty on Posterior Support in Bayesian Phylogeographic Generalized Linear Models

The use of generalized linear models in Bayesian phylogeography has enabled researchers to simultaneously reconstruct the spatiotemporal history of a virus and quantify the contribution of predictor variables to that process. However, little is known about the sensitivity of this method to the choice of the discrete state partition. Here we investigate this question by analyzing a data set containing 299 sequences of the West Nile virus envelope gene sampled in the United States and fifteen predictors aggregated at four spatial levels. We demonstrate that although the topology of the viral phylogenies was consistent across analyses, support for the predictors depended on the level of aggregation. In particular, we found that the variance of the predictor support metrics was minimized at the most precise level for several predictors and maximized at more sparse levels of aggregation. These results suggest that caution should be taken when partitioning a region into discrete locations to ensure that interpretable, reproducible posterior estimates are obtained. These results also demonstrate why researchers should use the most precise discrete states possible to minimize the posterior variance in such estimates and reveal what truly drives the diffusion of viruses.

Effects of thickness and orientation on the small scale fracture behaviour of additively manufactured Ti-6Al-4V

The effects of sample location, orientation, and thickness on the microstructure and resulting tensile properties of miniature SLM and SEBM AM samples of Ti-6Al-4V has been determined. Microstructure and mechanical property variations in the miniature samples are shown to be related to build orientation and also partly to specimen thickness and position within the build chamber. The present work is our initial attempt to develop a systematic approach for characterization of the microstructure (including defects via tomography) and mechanical properties on miniature AM test specimens that can also be used to reveal issues related to process stability (e.g. fluctuations in build conditions). The discussion is also included regarding their relevance to miniature samples that can be manufactured along with parts, excised from larger samples, and/or excised from actual manufactured components.

Adenosine triphosphate bioluminescence for hygiene testing of rubber liners and tubes on dairy farms

Prevention of biofilm formation in milking equipment is important to ensure good hygiene quality of raw milk. Key factors to achieving good results are a successful cleaning procedure and a method to check the cleanliness of milking equipment surfaces. Adenosine triphosphate bioluminescence is a fast and easy method for investigating bacterial contamination of surfaces. However, previous studies on the potential of ATP bioluminescence to assess the hygiene status of milking equipment have been hampered by lack of a validated test procedure. The aim of this work was therefore to establish a test procedure for assessing the cleanliness of milking equipment using ATP bioluminescence, and apply the method on-farm to study the hygiene status of aging rubber material in milking equipment. In developing the test procedure, the effects of sampling location in tubes and liners, sampling of dry versus wet barrels, milking point in the parlor, and acid or alkali detergent on ATP values were investigated. The results showed that, to obtain reproducible results, replicate sampling from the same milking points in the parlor is important. For milk tubes, samples should preferably be taken from the milk meter side, for liners on the inside of the barrel. For best results, sampling should be performed after use of alkali detergent. No beneficial effect was observed of sampling dry liner barrels, so sampling in the standardized test procedure is performed directly after cleaning. The standardized test procedure was used on 3 different commercial farms and sampling was initiated after replacement of old rubber parts. On one of the farms, additional sampling was performed to evaluate total bacteria count and determine the association with ATP level. The results suggest that, provided an efficient cleaning procedure is used, the hygiene quality of milking equipment can be maintained during the recommended lifetime of the rubberware. However, due to occasional variation in cleaning efficiency between milking points and liner barrels, random sampling on single occasions can lead to incorrect conclusions. Replicate sampling over time is therefore important for correct interpretation of ATP bioluminescence data. If ATP levels are very high, complementary sampling for total bacteria count should be used to verify that the level is due to bacterial contamination, and not other organic ATP-contributing material (e.g., milk residues).

The effects of sampling location and turbulence on discharge estimates in short converging turbine intakes

ABSTRACTStandards provide recommendations for best practice when installing current meters to measure fluid flow in closed conduits. A central guideline requires the velocity distribution to be regular and the flow steady. Because of the nature of the short converging intakes typical of low-head hydroturbines, these assumptions may be invalid if current meters are intended to be used to estimate discharge. Usual concerns are (1) the effects of the number of devices, (2) the sampling location and (3) the high turbulence caused by the presence of fish diversion screens. These three effects were examined in the present study by using 3D simulated flow fields in both steady-state and transient modes. In the process of describing an application at an existing hydroturbine intake at Ice Harbor Dam, the present work outlined the methods involved, which combined computational fluid dynamics, laboratory measurements in physical models of the hydroturbine, and current meter performance evaluations in experimental settings. The main conclusions in this specific application were that a steady-state flow field sufficed to determine the adequate number of meters and their location, and that both the transverse velocity and turbulence intensity had a small impact on estimate errors. However, while it may not be possible to extrapolate these findings to other field conditions and measuring devices, the study laid out a path to conduct similar assessments in other applications.

Effect of sampling location, release technique and time after activation on the movement characteristics of scallop (Pecten maximus) sperm

Sperm characteristics of scallops have not been well described in the scientific literature. The effects of sperm release technique (thermal shock versus serotonin injection), of sperm collection technique (testis sampling ver- sus serotonin injection), of sperm sampling location along the genital tract, of in vitro sperm maturation, and of time post activation on scallop sperm characteristics were assessed in the present work. Whatever sperm release technique used, no significant differences were observed regarding the percentage of motile spermatozoa and the velocity of the average path (VAP). Compared to testicular sperm, a higher percentage of motile spermatozoa, VAP and intracellular adenosine triphosphate (ATP) content were observed for sperm shed after serotonin injection. From the distal part of testes up to the gonopore, an increase of the percentage of motile spermatozoa and VAP was assessed, suggesting a sperm 'maturation process' along the genital ducts. A higher increase in the percentage of motile sperm was recorded during a 5 min incubation of testicular sperm in seawater containing 2 mM serotonin and seawater containing 10 mM caffein compared to seawater (control). In addition, a higher VAP was assessed, incubating testicular sperm in caf- fein, compared to control or serotonin. Then, the percentage of motile spermatozoa, VAP and intracellular ATP content exhibited a progressive reduction during the 10 h swimming period. Mean values of the percentage of motile spermato- zoa, VAP, sperm track linearity (LIN) and intracellular ATP content recorded at the beginning of the movement period for sperm samples collected after intragonadal serotonin injection, were 82 ± 7%, 162 ± 15 µ ms −1 ,0 .33 ± 0.12 and 212 ± 133 nmol ×10 −9 spermatozoa (n = 9 males), respectively. The present study confirms the existence of a sperm maturation process along scallop genital ducts. In addition, the cessation of scallop sperm movement can be explained by the exhaustion of ATP content at the end of the movement phase.

Bacterial Communities in Central European Bumblebees: Low Diversity and High Specificity

Recent studies on the microbial flora of the honeybee gut have revealed an apparently highly specific community of resident bacteria that might play a role in immune defence and food preservation for their hosts. However, at present, very little is known about the diversity and ecology of bacteria occurring in non-domesticated bees like bumblebees, which are of similar importance as honeybees for the pollination of agricultural and wild flowers. To fill this gap in knowledge, we examined six of the most common bumblebee species in Central Europe from three locations in Germany and Switzerland for their bacterial communities. We used a culture-independent molecular approach based on sequencing the 16S rRNA gene from a selection of individuals and examining a larger number of samples by terminal restriction fragment length polymorphism profiles. The gut flora was dominated by very few and mostly undescribed groups of bacteria belonging to the Proteobacteria, Bacteroidetes, Firmicutes and Actinobacteria. This core set of bacteria was present in all of the examined bumblebee species. These bacteria are similar to, but distinct from, bacteria previously described from the honeybee gut. Significant differences were observed between the communities of bacteria in the different bumblebee species; the effect of sampling location was less strong. A novel group of Betaproteobacteria additionally shows evidence for host species-specific genotypes. The gut flora of bumblebees therefore is apparently composed of relatively few highly specialized bacteria, indicating a strong interaction and possibly important functions with their hosts.

Effects of sampling location and time, and host animal on assessment of bacterial diversity and fermentation parameters in the bovine rumen

To investigate, using culture-independent methods, whether the ruminal bacterial structure, population and fermentation parameters differed between sampling locations and time. The detectable bacteria and fermentation parameters in the digesta from five locations in the rumen of three cows at three time points were analysed. The PCR-denaturing gradient gel electrophoresis (PCR-DGGE) profiles were similar among digesta samples from five locations (95.4%) and three time points (93.4%) within cows; however, a lower similarity was observed for samples collected from different host animals (85.5%). Rumen pH and concentration of volatile fatty acids (VFA) were affected by time points of sampling relative to feeding. The detectable bacterial structure in the rumen is highly conserved among different locations and over time, while the quantity of individual bacterial species may change diurnally in response to the feeding. This study supplies the fundamental understanding of the microbial ecology in the rumen, which is essential for manipulation of ruminal microflora and subsequent improvement in animal production.

Effect of Sampling Location on the Air Void Analyzer Test Results on Concrete Pavements: Evaluation of Data from a 16 State-Pooled Fund Project

Abstract The objective of this study was to evaluate the effect of sampling location on the air void analyzer (AVA) results from a 16 state-pooled fund study. The samples were obtained at locations ahead of the paver and behind the paver on a vibrator trail and between vibrator trails. The AVA air content, specific surface, spacing factor, and percent of air voids less than 300 μm in diameter were analyzed. The total air content of concrete ahead and behind the paver was also measured according to ASTM C231 for comparison. The ASTM C231 test results showed a significant drop in total air content of the samples behind the paver compared with the samples in front of the paver. The results show that the total air content is not an indicator of the spacing factor or percent of air voids less than 300 μm in diameter. There is no significant difference in the AVA results between the samples obtained on a vibrator trail and those obtained between vibrator trails based on the data from all 16 states. When the data for each state were studied individually, the data from some states showed a significant difference in the percent of air voids less than 300 μm (D≤300 μm) as well as the specific surface between the samples obtained ahead and behind the paver. The results imply that vibration removes mainly the large air voids in concrete, and this feature can be captured by the AVA test but not by the conventional ASTM C231 pressure meter test.

Numerical model of a large-scale oxygen consumption fire calorimeter

The present study introduces a volumetric heat and mass source model to investigate the flow field inside the hood and duct system and optimize the sampling technique in a large scale fire calorimeter. The model was validated using experimental measurements of the oxygen depletion factor, gas temperature and heat release rate. The calculated heat release rates determined using the CFD model were in good agreement with the experiments with the maximum discrepancy between the simulations and experiments being less than 5%. A series of CFD simulations were performed to examine the effects of sampling location, and the number of sampling points on the uncertainty of the heat release calculation. Detailed flow characteristics were analyzed to understand the complicated internal duct flow.

Effect of sample location on the reliability based design of pad foundations

Site investigations that aim to sufficiently characterize a soil profile for foundation design, typically consist of a combination of in situ and laboratory tests. The number of tests and/or soil samples is generally determined by the budget and time considerations placed upon the investigation. Therefore, it is necessary to plan the locations of such tests to provide the most suitable information for use in design. This is considered the sampling strategy. However, the spatial variability of soil properties increases the complexity of this exercise. Results presented in this paper identify the errors associated with using soil properties from a single sample location on a pad foundation designed for settlement. Sample locations are distributed around the site to identify the most appropriate sample location and the relative benefits of taking soil samples closer to the center of the proposed footing. The variability of the underlying soil profile is also shown to a have a significant effect on the errors due to sampling location. Such effects have been shown in terms of the statistical properties of the soil profile. The performance of several common settlement relationships to design a foundation based on the results of a single sample location have also been examined.

Trace element concentrations in the Pacific harbor seal (Phoca vitulina richardii) in central and northern California

To determine concentrations of trace elements (THg, MeHg, Se, and Pb) in tissues of the Pacific harbor seal (Phoca vitulina richardii), live (n=186) and dead seals (n=53) were sampled throughout central and northern California from March 2003 to January 2005. There were significant differences in THg concentrations in blood and hair based on age (p<0.001). Adult male harbor seals had greater THg concentrations in their hair than adult female harbor seals (p<0.003). THg concentrations in liver increased linearly with age and delta15N (p<0.001); whereas, MeHg concentrations in liver increased exponentially until approximately 5 years of age with an asymptote at 1.3 microg/g wet weight. MeHg expressed as a percentage of THg (%MeHg) was best described by a decay function (r2=0.796, p<0.001), decreasing to a minimum at 4 years of age. Hepatic Se increased with age and was in equimolar ratios with THg in adults; whereas, molar ratio of Se:THg in pups deviated from a 1:1 ratio. Significant differences among study locations in THg concentrations in blood and hair were not detected. Assessing the possible effect of sampling location on Hg concentrations, however, was confounded and limited by lack of equal sample sizes for basic age and sex cohorts, a common dilemma in pinniped research.

Experimental study of environmental tobacco smoke particles under actual indoor environment

Environmental tobacco smoke (ETS) is a major source of human exposure to airborne particles. In order to provide more information necessary for human exposure investigations, the aim of the work presented here is to investigate experimentally the variation of the ETS particle concentration and size distribution under an actual indoor environment, in a room of 30 m 3, using human smokers. The effect of number of cigarettes and brands of cigarettes, the effect of sampling location and the effect of ventilation rates were investigated. The results indicated little difference in the geometric mean diameter (GMD) of the ETS particles from those in background air. Under a ventilation rate of 0.03 m 3/s, the concentration of the ETS particles reached a peak value at the sampling point shortly after completing the smoking process. The GMD first increased due to coagulation and diffusion deposition, and finalize decreased due to the effect of ventilation. Smoking two cigarettes at the same time would increase the initial concentration and led to an increase in GMD of the ETS particles. Two different brands of cigarette with different tar contents released ETS particles of different GMDs but similar particle concentrations. Spatial variation in particle concentration was obvious only in the first 600 s of the tests and tended to fade out subsequently. Stronger ventilation would reduce the concentration and GMD of the particles.

Evaluation of the Effect of Sampling Location on Laboratory-Measured Quality Control Parameters

The sampling of hot-mix asphalt (HMA) is an important part of the quality control testing process. The quality of the sample can have a significant effect on the test results. When a sample of HMA is taken, the technician's goal should be to obtain a sample that is representative of the mixture that will be placed on the pavement and is not segregated or contaminated by foreign materials. Several possible choices exist for sampling locations. Samples may be taken from the back of the haul truck at the plant with either a shovel or a robotic sampling device. Samples can be taken at the paving site directly behind the spreader after the mix has been released from the screed but before the first roller has passed over it. Samples can also be taken with cores being cut from the compacted roadway. Each of these methods has its advantages and disadvantages. For this study, samples of two mixes were taken at various locations (truck by shovel, truck by robotic device, behind the spreader, and cores) for a period of several days and tested for asphalt content, gradation, and percent air voids. The results were compared to determine what, if any, effect sampling location has. Overall, although there is little statistical difference in the laboratory properties due to sampling location (except for percent asphalt content), it does appear that segregation may be occurring in the samples obtained from the truck by using a shovel (finer gradation, higher asphalt content, and lower percent air voids). Use of the remote truck sampling device appears to result in properties that more closely match the properties of the mix sampled behind the spreader for Mix 2.

Placental cadmium and progesterone concentrations in cigarette smokers

Cadmium and progesterone concentrations were evaluated in term placentas collected from 56 healthy parturients in the city of Zagreb. Concentrations of lead, iron, zinc, and copper in placentas were analyzed. Data collected by questionnaire identified 29 nonsmoking and 27 smoking women. From each placenta, three samples from different locations were taken. Metals were measured by atomic absorption spectrometry. Progesterone was determined by specific radioimmunoassay in homogenized and lyophilized tissue samples after steroid extraction with ethanol. No effect of sample location was found. In placentas of smoking women an increase in cadmium, reduced progesterone and a decrease in iron concentrations were found. Placental copper and zinc concentrations were not altered. In conclusion, the results present new evidence that maternal smoking reduces placental progesterone content and support the established association of smoking with placental cadmium.