Effect Of Daily Variation Research Articles

Concentration of Urine Samples Improves Sensitivity in Detection of Strongyloides-Specific IgG Antibody in Urine for Diagnosis of Strongyloidiasis.

Detection of IgG in urine is an efficient method comparable to that in serum for diagnosis of strongyloidiasis, but the effects of daily variation in urine dilution on diagnostic accuracy are not clearly known. This study evaluated the effects of urine concentration on the detection of parasite-specific IgG by urine enzyme-linked immunosorbent assay (ELISA), particularly in individuals with borderline results or false-negative diagnosis. Optimal concentration conditions were established by comparing Strongyloides-specific IgG antibody levels between unconcentrated and concentrated urine in participants with different infection intensities, namely, healthy control (HC), low-negative (LN), high-negative (HN), and low-positive (LP) groups. The optimal condition was selected and validated in a field trial study. The final urine concentration protocol required centrifugation at 4,000 × g at 4°C for 10 mins using the Amicon concentrator tube. This protocol was validated in groups of participants with various diagnoses according to urine ELISA and fecal examination (n = 148). The concentrated-urine ELISA increased the proportion of positive results in the LN group by 68.2% and by 100% in the HN group. Significantly elevated IgG antibody levels were seen in the LP group. In the group that was false negative by urine ELISA but positive by fecal examination (n = 28), concentrated-urine ELISA yielded 100% positive results. Overall, the frequency estimates of Strongyloides stercoralis were 23.6% by fecal culture, 27% by standard urine ELISA, and 90.5% by concentrated-urine ELISA. The concentration of urine samples prior to analysis by ELISA improved the sensitivity for diagnosis and is potentially useful in the diagnosis of strongyloidiasis in immunocompromised individuals or in low-prevalence areas.

EP-1782: Effect of daily variation in rectal and bladder filling: an analysis of planned versus actual dose

EP-1782: Effect of daily variation in rectal and bladder filling: an analysis of planned versus actual dose

Effect of daily variation on the seasonality of testate amoebae community structure in different environments of a Neotropical floodplain

<p>Ecological communities are constantly restructuring in the short and long term in response to population dynamics and environmental variables. This study evaluated the structure of arcellinid and euglyphid testate amoebae planktonic communities in three environments of the Upper Paraná River basin, Brazil. We hypothesised that the community structure of testate amoebae is differentially influenced by environmental conditions, mainly in isolated lentic ecosystems, due the effect of the low-water period. In addition, we predicted that the response of testate amoeba communities to environmental changes is also affected by the distinct hydrodynamic characteristics of the environment. Plankton were sampled in the low- and high-water periods, and physical and chemical variables were calculated for each site. In order to evaluate the influence of environmental conditions on the variation in testate amoebae community structure over time, a time-lag analytical approach was used and significance was estimated using a Mantel test. A Kendall test coefficient was used to estimate the maintenance of species abundance on each day when sampling was carried out and for each water body. A redundancy analysis was also performed to assess the responses of testate amoeba communities to environmental change in the three studied environments. Bray–Curtis dissimilarity indices were calculated for the testate amoeba communities and the significance of the differences between communities was estimated using a Mantel test. Seventy-five taxa belonging to six families were identified. Environmental conditions influenced the richness, abundance, and dominance pattern of the testate amoebae communities, and distinct hydrodynamic characteristics of the environments affected the establishment of community structure.</p>

Estimation and correction for the effect of sound velocity variation on GPS/Acoustic seafloor positioning: An experiment off Hawaii Island

A GPS/Acoustic experiment on the southeastern slope of Hawaii Island presented precise seafloor positioning in the condition of large water depth (2.5—4.5 km) and large velocity variations. We estimated sound velocity variations from acoustic ranging, and found that temperature variation can well explain the velocity variation. The effect of daily variation in the sound velocity amounted to +/- 0.7 m on acoustic ranging of 4—7 km with a fixed velocity structure. CTD data observed about every 3 hours could decrease the range residuals to +/- 0.4 m. These large residuals were fairly well canceled in the positioning of the array center of three acoustic transponders. The estimated precision of the array center positioning was about 3 cm in latitude and longitude.

Effects of daily variation in outdoor particulates and ambient acid species in normal and asthmatic children

Background: Evidence suggests that the respiratory health of children may be adversely affected by daily variation in outdoor pollutants, particularly ozone and particulates. However, data from the UK are sparse...

Sulphur Dioxide Exposure and Lung Function in a Norwegian and Russian Population Living Close to a Nickel Smelter

ABSTRACTThe Norwegian-Russian border area is polluted by sulphur dioxide (SO2) emitted from a Russian nickel smelter in the city of Nikel. We studied the effects of daily variations in SO, on the lung function levels of people on both sides of the border. A cross-sectional population-based study was performed among adults in Sor-Varanger, Norway (n=3438) and Nikel, Russia (n= 1613). All subjects were assigned 24h mean SO2 concentrations for their day of screening and the day before on basis of residency. The SO;-con-centrations were compared with the daily recordings of forced expiratory volume in one second expressed as percentage of the predicted value (FEV1% predicted). In Sor-Varanger, no significant associations between SO, and FEV1% predicted were found. In Nikel, FEV1% predicted was exceeded non-systematically in some of the exposure categories (10-50, 50-90, or >90 μg/m3) compared to the reference exposure group (0-10 μg/m1). In conclusion, neither of the study populations suffered from a measurable reduction in lung function when SO2 increased above the reference level. (Int J Circumpolar Health 2001; 60: 342-359)

Diurnal and annual variation of the sensation distance of odour emitted by livestock buildings calculated by the Austrian odour dispersion model (AODM)

The diurnal and annual variation of distances for different odour thresholds is investigated by the dynamic Austrian odour dispersion model (AODM) consisting of an emission module, a dispersion module, and a module to calculate instantaneous odour concentrations. The effect of daily variations in odour production, ventilation rates and indoor air temperature are included in impact assessments. The ambient half-hour odour concentrations calculated by a regulatory Gaussian plume model are transformed to instantaneous values representative for the duration of a single breath by an attenuation function decreasing the peak-to-mean ratio with increasing wind velocity, stability, and distance from the source. The resultant distances for different odour thresholds and their dependence on meteorological parameters are investigated and discussed in detail, focussing on the distance for the detection limit, 1 OU m −3, the so-called sensation distance. The results suggest a stronger dependence of the sensation distance upon variation in meteorological conditions than diurnal and annual variations in odour emission rates.

Refining the Use of Point Counts at the Scale of Individual Points in Studies of Bird-Habitat Relationships

Useful sampling guidelines have recently been provided to improve the precision of bird population parameter estimates from point count data. Less attention has been given, however, to the issue of accuracy or completeness of counts at each sampling point. While it may not be critical in studies that compare average counts among study plots, completeness of counts at the level of individual points may pose several problems in studies that assess relationships between response variables (species' occurrence or abundance) and explanatory variables (vegetation structure, size and isolation of the fragment, proportion of interior habitat) on a point by point basis. Reliability of models in such studies is greatly dependent on the accuracy of counts at each point. We examined how bias of incomplete counts could be minimised through refinements of the point-count method. Six forest types of the northeastern deciduous forest in Quebec (Canada) were intensively surveyed during an entire breeding season. Census performances of the point-count method for measuring species richness at individual points were assessed by resampling the original data set for a simulated census protocol of two visits at a point. Effects of daily variation, time of season, time of day, and count duration were tested. Census performances of counts conducted the same day were significantly poorer than counts from different days. Census performances were influenced by the time of season during which counts were conducted. When pooled across habitats, census performances for counts that combined visits at the beginning and at the end of the breeding season were significantly better than counts that were concentrated in either one of these periods. The 05:00 to 08:30 morning period yielded the best results for five of the six habitats. Census performances in open field were, however, significantly better during the first sampling period (04:30), suggesting that bird censuses in open habitats could be initiated before sunrise. Longer counts (25 and 20 min) greatly improved species richness estimates at a point. For studies that focus on comparisons at the scale of individual points, longer counts are preferable to short counts (15 and 10 min). We stress the importance of the scale (study plots or individual points) at which statistical analyses of point count data are conducted in the decision-making process of point count sampling procedures.

環境温度の日内変動幅が子豚の成長および消化率におよぼす影響

環境温度の日内変動幅が子豚の成長および消化率におよぼす影響

Effect of daily variation in weather and sleep on seasonal affective disorder

Analysis of daily self-ratings of energy for 10 patients diagnosed with seasonal affective disorder (SAD) revealed statistically significant seasonal patterns in eight patients (with all patients showing the most energy in the summer and the least energy in the winter). When weather was controlled for, the seasonal patterns in energy persisted in seven of the eight patients. In a lesser number of subjects (four), there were significant effects of weather after controlling for season; however, when the effects of weather on energy were examined separately for each season, 8 of the 10 subjects were found to be influenced by weather in at least one season. Daily sleep data showed statistically significant seasonal patterns in all 10 patients (with 6 subjects showing maximum sleep in winter and 4 in summer). As for the relationship between energy and sleep, a loss of energy appeared to predict longer sleep on that night and the next night (7 of 10 patients), whereas there was no evidence that prolonged sleep influenced energy on the following and subsequent days.

Influence of Daily Variation of Flow and Pollution Load on the Performance of Submerged Anaerobic/Aerobic Biofilm System

Effects of daily variation of flow on the performance of submerged anaerobic/aerobic biofilm systems were investigated both by laboratory study using synthetic wastewater and by field study using gray water. In laboratory study, concentration of dissolved organic carbon (DOC) in effluent from anaerobic filter fluctuated with daily variation of flow when average hydraulic retention time (HRT) was below 10 h. However, daily mean values of DOC under the varied flow was almost the same as those under constant flow within the same daily mean HRT. Aerobic filter linked to anaerobic filter reduced the concentration of DOC satisfactorily though the concentration in anaerobic filter increased under short HRT. In field study, percent removal of organic carbon by anaerobic filter was considerably smaller (20-30%) than that in laboratory study (90-95%) both at HRT of 20 h though it was improved up to 60-80% by aerobic filter. Effects of peaking factor of flow on the variation of DOC were evaluated by mathematical analysis. It seemed that the peaking factor hardly affected daily mean values of DOC within the same daily mean HRT though maximum values of DOC increased with the increase of peaking factor.

The Variability of the Net Radiation Ratio

Prediction equations for estimating evaporation from bodies of water, often require values of net radiation. Solar radiation data are usually more accurate and more readily available than measurements of net radiation. Measured solar radiation and the mean ratio of net radiation to solar radiation have been used to estimate the net radiation levels required to predict evaporation rates. However, although the average net radiation ratio is relatively stable from year to year the effect of daily variation in the net radiation ratio on evaporation estimates has not been investigated. An empirical energy balance and measurements of pan evaporation and meteorological factors are used to examine the effect of the average daily variation on evaporation rates computed with the mean net radiation ratio. The results indicate that the average daily variation from the mean net radiation ratio may produce an error of approximately 13 per cent in an estimate of daily evaporation when the mean net radiation ratio is used. However, daily variability in the net radiation ratio has little influence on the regeneration of a large number of evaporation estimates. Estimated values of the net radiation ratio and its variability are compared with observed values from polar climates.