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PubMed2006

An investigation of concurrent sex partnering in two samples of drug users having large numbers of sex partners.

The objective of this study was to quantitatively measure the nature of concurrent sex partnering in two samples of drug users having large numbers of sex partners. The purpose of this study was to measure concurrent sex partnering and overlap in concurrent sex partners in two samples of drug users in which some or all participants were trading sex-for-money. Two samples having large numbers of sex partners were used to conduct the analyses: drug-using male sex workers (MSW) and male and female crack cocaine smokers (CS) having vaginal sex. To reflect the quality of concurrent partnering, three measures were used: the proportion of the samples having concurrent partners; the proportions of the samples having intimate, casual, and sex-for-money of partners; and overlap in concurrent partners. Proportions of each sample having concurrent partners were essentially the same. However, the kinds of concurrent partners and overlap in concurrent partners were significantly different. Concurrent partners in the MSW sample were mostly sex-for-money or sex-for-drugs partners. Most concurrent partners in the CS sample were initimate or casual sex partners. Overlap in concurrent partners was also significantly different. The measure of overlap for the CS sample was three times higher than that of the MSW sample. These data suggest that concurrent sex partnering in the two samples, beyond the proportion having concurrent partners, was different. The patterns of concurrent sex partners in each sample may reflect different reasons for engaging in concurrent partnering. Different reasons for engaging in concurrent partnering may also be reflected in different overlap scores between the two samples. Efforts should be made in future studies to better capture the complexities of concurrent partnering and to examine the implications of these for disease spread and control.

Adult↗
PubMed1993

Frequent blood sampling changes the plasma concentration of LH and FSH and the ovulation rate in Merino ewes.

During earlier studies we observed that ewes housed and sampled intensively to measure pulses of LH in plasma had a higher ovulation rate than similar ewes housed outside. In Expt 1, we pursued this observation by testing whether the increase was due to effects of housing or collection of blood samples. Ewes sampled at intervals of 4 h for 2 days before progestagen sponge removal and 2 days after sponge removal, and every 20 min for 12 h the day before sponge removal and every 10 min for 4 h on the day of sponge removal had a higher ovulation rate than ewes that were not sampled (1.72 versus 1.41; P < 0.05). The ovulation rate of the ewes housed indoors but not sampled was similar to that of ewes that remained in the paddock (1.43). In Expt 2, we studied the effects of blood sampling in three groups of 20 ewes sampled every 20 min for different periods of 24 h. Ewes from all three groups were sampled the day before sponge removal (day -1) and, in addition, one group of ewes was sampled for the previous 48 h (i.e. days -3 to -1) and another group was sampled on day -8. The frequency of LH pulses was lower (P < 0.05) in ewes sampled for the first time on day -1 compared with the frequency of LH pulses in groups also sampled earlier in the cycle (day -8 or days -3 and -2). In ewes sampled on days -3 to -1, the frequency of LH pulses was low for the first 24 h and then increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1999

Growth of infants prenatally exposed to cocaine/crack: comparison of a prenatal care and a no prenatal care sample.

OBJECTIVE: It has not been possible to draw firm conclusions about the effects of prenatal cocaine exposure because of methodologic problems involved in the conduct of this research. This study, designed to overcome some of these methodologic problems, is a prospective, longitudinal investigation of the effects of prenatal cocaine/crack exposure on neonatal growth in two samples, one with and one without prenatal care (PC). METHODS: Women in the PC sample (n = 295) were interviewed at the end of each trimester about their use of cocaine, crack, alcohol, tobacco, marijuana, and other drugs. Women in the no prenatal care (NPC) sample (n = 98) were interviewed at delivery about their drug use during each trimester of pregnancy. In both samples, information was also obtained about sociodemographic, lifestyle, psychologic, and social support characteristics. Both samples consisted of women who were predominantly low income, single, and high school educated. Of the women, 48% in the PC sample were black; 81% in the NPC sample were black. Infants were examined during the postpartum hospital stay by project nurses who were blind to maternal substance use status. RESULTS: Women in both samples who used cocaine/crack during pregnancy were older, had lower family incomes, and used more alcohol than did women who did not use cocaine/crack during pregnancy. In addition, women in the NPC sample were more likely to be black, less educated, gained less weight during pregnancy, and used more alcohol than did women in the PC sample, regardless of cocaine use. In both samples, cocaine/crack use during early pregnancy predicted reduced gestational age, birth weight, length, and head circumference, after controlling for the significant covariates of cocaine use. In a comparison of the samples, the offspring of the NPC/cocaine group were significantly smaller than were the offspring of the PC/no cocaine group, whereas the offspring of the PC/cocaine and NPC/cocaine groups did not differ. CONCLUSIONS: These results indicate that exposure to cocaine/crack during early pregnancy decreases the intrauterine growth of exposed offspring in women with and without PC. Each of the growth parameters was affected indicating symmetric growth retardation. The adequacy of PC was not a significant factor in determining the difference between cocaine-exposed and nonexposed infants. These samples are being followed throughout childhood to determine whether there are long-term effects of prenatal cocaine/crack exposure on growth.

Birth Weight↗
PubMed2005

Detection and evaluation of endocrine-disruption activity in water samples from Portuguese rivers.

Water samples (n = 183) from Portuguese rivers were tested for the presence of endocrine disruptors using the recombinant yeast assay (RYA) combined with chemical identification of compounds having endocrine-disruption properties by liquid chromatography coupled to mass spectrometry. Ten selected locations were sampled monthly for a period of 20 months, from April 2001 to December 2002. More than 90% of samples showed either no detectable or low levels of estrogenicity (<0.1 ng/L of estradiol equivalents). The remaining samples (17 in total, 9.3%) showed estrogenicity values ranging from 0.1 to 1.7 ng/L of estradiol equivalents; only two samples showed values greater than 1 ng/L of estradiol equivalents. Most highly estrogenic samples (13 of 17 samples) originated in five sampling sites clustered in two zones near Porto and Lisbon. Chemical analysis detected alkylphenolic compounds (octyl- and nonylphenol plus nonylphenol ethoxylates) in all samples, albeit at concentrations less than 1 microg/L for each compound in 80% of samples. Total analyte concentration exceeded 10 microg/L in only 10 samples, with all but one of those originating from only two sampling sites. In these two locations, a good correlation was observed between the concentrations of octylphenol, nonylphenol, and to a lesser extent, bisphenol A in the samples and their estrogenicity values as calculated by RYA. We conclude that estrogenic activity can be explained by alkylphenol contamination in only these sites; for the remainder, we propose that pesticides and urban waste may be the main factors responsible for estrogenic contamination.

Biological Assay↗
PubMed2006

Computing asymptotic power and sample size for case-control genetic association studies in the presence of phenotype and/or genotype misclassification errors.

It is well established that phenotype and genotype misclassification errors reduce the power to detect genetic association. Resampling a subset of the data (e.g, double-sampling) of genotype and/or phenotype with a gold standard measurement is one method to address this issue. We derive the non-centrality parameter (NCP) for the recently published Likelihood Ratio Test Allowing for Error (LRTae) in the presence of random phenotype and genotype errors. With the NCP, power and sample size can be analytically determined at any significance level. We verify analytic power with simulations using a 2**k factorial design given high and low settings of: case and control genotype frequencies, phenotype and genotype misclassification probabilities, total sample size, ratio of cases to controls, and proportions of phenotype and/or genotype double-samples. We also perform example applications of our method assuming equal costs for the LRTae method and the standard method that does not use double-sample information (LRTstd) to determine if power gain due to double-sampling a proportion of samples outweighs the reduction in sample size due to additional costs in obtaining double-samples. Our results showed a median difference of at most 0.01 between analytic and simulation power for the factorial design settings, with maximum difference of 0.054. For our cost/benefits analysis calculations, results for genotype errors are that double-sampling appears most beneficial (in terms of power gain) when cost of double-sampling is relatively low, irrespective of the proportion of individuals double-sampled. In the presence of phenotype error, there is always power gain using the LRTae method for the parameter settings considered. We have freely available software that performs power and sample size calculations for the LRTae method and cost/benefits analyses comparing power for LRTae and LRTstd methods assuming equal costs.

Journal Article↗
PubMed2005

Evaluation of the effect of routine histologic processing on the size of skin samples obtained from dogs.

OBJECTIVE: To determine the effects that routine histologic processing has on the dimensions of samples of normal skin of dogs and assess whether the inclusion of a muscle or fascial layer in such samples alters those effects. SAMPLE POPULATION: Skin samples obtained from 6 medium-sized adult dogs with grossly normal skin. PROCEDURE: From each dog, skin samples (with or without underlying fascia or muscle) were obtained from 3 sites bilaterally (6 samples/dog) and processed routinely for histologic evaluation; their dimensions were measured at intervals during the experiment. RESULTS: As a result of processing, skin samples decreased in size (combined percentage change in length and width) and increased in thickness, compared with their original dimensions. Samples without fascia or muscle decreased in size by 21.1% to 32.0% and increased in thickness by 45.1 % to 75.8%. The site of sample origin influenced processing-associated changes in sample size but did not affect the change in thickness. Decreases in dimensions did not vary with inclusion of fascia but did vary with inclusion of muscle. The change in thickness did not vary with inclusion of a layer of fascia or muscle. CONCLUSIONS AND CLINICAL RELEVANCE: Processing of skin samples obtained from dogs for histologic evaluation can cause changes in sample dimensions; samples may decrease in length and width by as much as 32% and increase in thickness by 75.8%, compared with their original dimensions. The presence of muscle in canine skin samples can restrict the amount of shrinkage in length or width associated with processing.

Animals↗
PubMed2002

Comparison of sampling methods for microbiological testing of beef animal rectal/colonal feces, hides, and carcasses.

This study compared sampling methods for detecting Escherichia coli O157:H7 and Salmonella in beef cattle feces and on hides and carcasses and for enumerating E. coli biotype I counts (ECC) on carcasses. Fecal samples were collected by rectal/colonal palpation and colonal sponge swabbing. Hides were sampled by sponge swabbing three sites, hair clipping, excision, rinsing, and gauze swabbing, whereas carcasses were sampled by three-site thoracic and pattern-mark sponge swabbing and tissue excision. Overall, irrespective of sampling method, 36.7, 13.3, and 0.0% of lots contained at least one E. coli O157:H7-positive hide, fecal, and carcass sample, respectively, while the corresponding prevalence of Salmonella was 70.0, 16.7, and 6.7%, respectively. For hide sampling, excision and gauze swabbing yielded the fewest (13.3%) E. coli O157:H7-positive samples, while hair clipping and sponge swabbing yielded the most (23.3%). None of the carcass-sampling methods detected E. coli O157:H7 or differed (P > 0.05) in their ability to enumerate ECC. Colonal swabbing was the most effective (10.0%) method for detecting E. coli O157:H7 in feces. No differences (P > 0.05) in Salmonella prevalence were observed between carcass-sampling methods, although three-site sponge swabbing and tissue excision detected the most (3.3%). Hide rinsing was the most effective (P < 0.05) Salmonella detection method (63.3%), but dangers associated with its application may preclude its use by industry; there were no differences (P > 0.05) among other hide-sampling methods. No differences (P > 0.05) in Salmonella detection were observed between fecal-sampling methods. Overall, three-site sponge swabbing was the most feasible and effective sampling method for the detection of E. coli O157:H7 and Salmonella on hides and carcasses.

Animals↗
PubMed1999

The effects of the extension of transit times on qualitative and quantitative bacterial culture after clinical sampling.

The effects of the extension of transit times on qualitative and quantitative bacterial culture after clinical sampling were investigated with the clinical samples, using the bacterial flora from the cancer portion inside the uterine cervix in 25 patients with the uterine cervical cancer. In the qualitative bacterial study, the strains of both aerobic and anaerobic bacteria detected were rather preserved for 6 hours after clinical sampling and decreased in a time-dependent manner in the samples of more than 6 hours after clinical sampling. In particular, number of anaerobic bacterial species detected remarkably decreased in the samples of more than 12 hours after clinical sampling. Therefore, prompt bacterial culture after clinical sampling, possibly within 6 hours after clinical sampling, may be crucial in order to detect most probable pathogenic anaerobic bacteria, particularly when anaerobic infection is suspected. In the quantitative bacterial study, the quantity of bacteria detected were rather preserved for 3 hours after clinical sampling and decreased in a time-dependent manner in the samples of more than 3 hours after clinical sampling. Therefore, quantitative bacterial culture should be performed within 3 hours after clinical sampling.

Adult↗
PubMed1999

Plug flow cytometry: An automated coupling device for rapid sequential flow cytometric sample analysis.

BACKGROUND: The tools for high throughput flow cytometry have been limited in part because of the requirement that the samples must flow under pressure. We describe a simple system for sampling repetitively from an open vessel. METHODS: Under computer control, the sample is loaded into a sample loop in a reciprocating eight-way valve by the action of a syringe. When the valve position is switched, the plug of sample in the sample loop is transported to the flow cytometer by a pressure-driven fluid line. By coupling the plug-forming capability to a second multi-port valve, samples can be delivered sequentially from separate vessels. RESULTS: The valve is able to deliver samples at rates ranging up to about 9 samples per minute. Each plug of sample has uniform delivery characteristics with a reproducible coefficient of variation (CV). Even at the highest sampling rate, carryover between samples is limited. CONCLUSIONS: Plug-flow flow cytometry has the potential to automate the delivery of small samples from unpressurized sources at rates compatible with many screening and assay applications.

Animals↗
PubMed1986

Retrospective coding in pigeons' delayed matching-to-sample.

In this study we examined how coding processes in pigeons' delayed matching-to-sample were affected by the stimuli to be remembered. In Experiment 1, two groups of pigeons initially learned 0-delay matching-to-sample with identical comparison stimuli (vertical and horizontal lines) but with different sample stimuli (red and green hues or vertical and horizontal lines). Longer delays were then introduced between sample offset and comparison onset to assess whether pigeons were prospectively coding the same events (viz., the correct line comparisons) or retrospectively coding different events (viz., their respective sample stimuli). The hue-sample group matched more accurately and showed a slower rate of forgetting than the line-sample group. In Experiment 2, pigeons were trained with either hues or lines as both sample and comparison stimuli, or with hue samples and line comparisons or vice versa. Subsequent delay tests revealed that the hue-sample groups remembered more accurately and generally showed slower rates of forgetting than the line-sample groups. Comparison dimension had little or no effect on performance. Together, these data suggest that pigeons retrospectively code the samples in delayed matching-to-sample.

Animals↗
PubMed1998

Assessment of the bacterial flora of the proximal part of the small intestine in healthy cats, and the effect of sample collection method.

OBJECTIVE: To investigate the bacterial flora of the proximal part of the small intestine of healthy cats and determine the effect of sample collection method on results of bacteriologic culture. ANIMALS: 25 healthy barrier-maintained specific-pathogen-free-derived cats. PROCEDURE: Aspirated, undiluted samples of proximal small intestinal juice were obtained via oral endoscopy (UEA), and a second sample was collected after instillation of 1 ml of sterile saline solution (diluted, DEA). Undiluted juice also was obtained by direct needle aspiration (NA) from the intestinal lumen. Samples for quantitative and semiqualitative bacteriologic examination were grown aerobically and anaerobically. RESULTS: Mean (range) log10 colony-forming units of total bacteria/ml were 6.2 (2.0 to 8.3) for NA, 6.0 (2.0 to 7.9) for UEA, and 4.9 (2.0 to 7.5) for DEA samples. One cat had no growth (< or = 2.0 colony-forming units/ml) for samples obtained using all 3 methods, and another cat had no growth for the DEA sample only. Mean total aerobic, anaerobic, and bacterial counts were not significantly different between NA and UEA methods, but these techniques yielded significantly higher mean counts than did DEA samples (P < or = 0.002, ANOVA). As a percentage of the total bacteria isolated, anaerobes constituted a median 35, 32, and 50% of the NA, UEA, and DEA samples, respectively. Good correlation was found between the NA and UEA samples for total bacteria, aerobes, and anaerobes (r > or = 0.830). CONCLUSIONS: Compared with human beings, healthy cats carry high numbers of bacteria in the proximal part of the small intestine. By comparison with NA samples, UEA samples accurately reflected bacterial populations in the small intestine, whereas DEA samples significantly underestimated these populations.

Animals↗
PubMed2005

Simulating the sensitivity of pooled-sample herd tests for fecal Salmonella in cattle.

Samples from livestock or food items are often submitted to microbiological analysis to determine whether or not the group (herd, flock or consignment) is shedding or is contaminated with a bacterial pathogen. This process is known as 'herd testing' and has traditionally involved subjecting each sample to a test on an individual basis. Alternatively one or more pools can be formed by combining and mixing samples from individuals (animals or items) and then each pool is subjected to a test for the pathogen. I constructed a model to simulate herd-level sensitivity of the individual-sample approach (HSe) and the herd-level sensitivity of the pooled-sample approach (HPSe) of tests for detecting pathogen. The two approaches are compared by calculating the relative sensitivity (RelHSe = HPSe/HSe). An assumption is that microbiological procedures had 100% specificity. The new model accounts for the potential for HPSe and RelHSe to be reduced by the dilution of pathogen that occurs when contaminated samples are blended with pathogen-free samples. Key inputs include a probability distribution describing the concentration of the pathogen of interest in samples, characteristics of the pooled-test protocol, and a 'test-dose-response curve' that quantifies the relationship between concentration of pathogen in the pool and the probability of detecting the target organism. The model also compares the per-herd cost of the pooled-sample and individual-sample approaches to herd testing. When applied to the example of Salmonella spp. in cattle feces it was shown that a reduction in the assumed prevalence of shedding can cause a substantial fall in HPSe and RelHSe. However, these outputs are much less sensitive to changes in prevalence when the number of samples per pool is high, or when the number of pools per herd-test is high, or both. By manipulating the number of pools per herd and the number of samples per pool HPSe can be optimized to suit the range of values of true prevalence of shedding of Salmonella that are likely to be encountered in the field.

Animals↗
PubMed2005

Maternal cell contamination of prenatal samples assessed by QF-PCR genotyping.

OBJECTIVES: To establish the genotype of cultured cells from a cohort of amniotic fluid and chorionic villus samples, and compare this genotype with that obtained from uncultured material from the same sample, in order to assess the frequency and significance of maternal cell contamination of prenatal samples. METHODS: Quantitative fluorescence-polymerase chain reaction (QF-PCR) was carried out by amplification of microsatellite markers using fluorescence-labelled primers, followed by quantitative analysis of the allele peaks on a genetic analyser. A multiplex of 12 primer pairs for four loci on each of chromosomes 13, 18 and 21 was used. RESULTS: A total of 307 prenatal samples were tested. Of the 254 amniotic fluid samples, 39.8% had some degree of bloodstaining, ranging from 5% bloodstaining in the cell pellet to heavily bloodstained fluid. Uncultured samples were tested by QF-PCR analysis and the cultured cells were tested by both QF-PCR and karyotype analysis. Of the samples, 90.2% had the same single genotype on direct and cultured material. Two samples (0.65%) were mosaic for an aneuploidy cell line. A second genotype, interpreted as maternal cell contamination, was identified in direct and/or cultured preparations in 9.1% of samples, 17.8% of which were not bloodstained. Seven amniotic fluid samples (2.8%) showed maternal cell contamination in cultured material. CONCLUSIONS: For heavily bloodstained amniotic fluid samples, a maternal blood specimen may help interpret the results of rapid trisomy testing, followed by confirmation of the fetal origin of cultured cells. QF-PCR analysis has established a higher incidence of maternal cell contamination of cultured amniocytes than previous reports; the presence of MCC (maternal cell contamination) in cultured cells from samples with no bloodstaining underlines the need for karyotype analysis of more than one XX culture.

Adult↗
PubMed2006

The prediction of criminal recidivism: the implication of sampling in prognostic models.

BACKGROUND: Instruments based on actuarial forensic risk assessment models are sensitive to the calibration sample, and the inclusion criteria for the subjects of a study population will influence the features of the resulting model. If the same instrument is used in populations that are not part of the calibration sample, the discriminative validity of the instrument is jeopardized; thus the definition of the calibration sample is very important. The aim of this study was to examine how sensitive prognostic models are to the calibration sample. METHOD: Two samples (N = 773) of offenders sentenced to at least 10 months in prison for a violent or sexual offense were used in this study. The "sanction sample" (recruited during August 2000, N = 515) consisted of all violent and sexual offenders actively administrated by the Criminal Justice System of Zurich, Switzerland. The "verdict sample" (recruited over two years, N = 258) included all offenders convicted in the Canton of Zurich during a two-year period. Both samples were unbiased, since all subjects that met the study criteria were included. In the first analysis, differences between the two samples were shown with respect to socio-demographic, criminological, and psychiatric variables using bivariate logistic regressions. In the second analysis, recidivism was estimated separately for both samples, using a logistic regression model as a function of a set of psychiatric, socio-demographic and criminological variables. RESULTS: Bivariate logistic regression showed that different risk factors for recidivism existed for both samples. CONCLUSION: Forensic risk assessment models are very sensitive to the calibration sample. There is strong evidence that, even when index-offenses and the socio-cultural background are the same, risk factors for recidivism differ depending on the stage of the judicial process in which the subjects are (e.g. whether a subject is indicted, on conditional release, on parole, or no longer under the supervision of a parole board). Unfortunately, none of the currently available actuarial risk assessment instruments that have been validated in European countries consider the different stages of the judiciary process.

Adult↗
PubMed1999

Pollen recovery in atmospheric samples collected with the Rotorod Sampler over multiple-day periods such as weekends.

BACKGROUND: Conventional wisdom holds that multiple-day samples should not be obtained with the Rotorod Sampler because sampling efficiency declines over long sampling periods such as weekends. OBJECTIVE: The purpose of this present investigation was to test this position under experimental conditions. METHODS: Atmospheric pollen samples were collected over 24-hour, 48-hour, and 72-hour periods by five Rotorod Samplers operated in a compact sampling array. Pollen counts obtained from the latter two sampling periods were compared with corresponding values computed from 24-hour samples. Differences in pollen recovery were assessed using Pearson's correlation coefficient and paired comparisons t-tests. RESULTS: Two hundred seventeen atmospheric samples were obtained between March 30 and October 8, 1998. Differences between the 48-hour and 72-hour samples and their computed counterparts were not statistically significant when the atmospheric pollen concentration was less than 100 pollen grains per cubic meter of air (p/m3). At higher pollen concentrations large quantitative and statistically significant differences were noted. CONCLUSIONS: These data suggest that particle loading on Rotorod collector rods caused sample quality to deteriorate when atmospheric pollen concentrations exceed 100 p/m3. Multiple-day sampling periods appear to be justified when the atmospheric pollen concentration is less than this threshold. Adjusting the Rotorod Sampler's duty cycle may offer a means to collect samples over periods longer than 24 hours during times of the year when pollen shed is heavy.

Air Pollution↗
PubMed1995

Effect of non-random sampling on the estimation of parameters in population genetics.

The amount and pattern of genetic variation in a population can be estimated from genes or DNA sequences sampled from the population. Although random sampling is assumed in almost all cases, we often do not know whether sampling is random or not. Using a simple non-random sampling model, the effects of non-random sampling on the estimation of parameters in population genetics were investigated. This non-random sampling model assumes that n genes are randomly sampled with replacement from m genes which were randomly sampled from a large random mating population, and various degrees of non-randomness can be generated by changing the value of m. The results obtained show that the effect of non-random sampling on the number of alleles and the number of segregating sites is substantially large whereas the effect of non-random sampling on heterozygosity and the average number of nucleotide differences is negligibly small unless non-randomness is extremely large. The effects of non-random sampling on the tests of neutrality were also investigated, and the results obtained indicate that the effect of non-random sampling is stronger on Fu and Li's tests than on Tajima's test.

Alleles↗
PubMed2003

Support, shape and number of replicate samples for tree foliage analysis.

Many fundamental features of a sampling program are determined by the heterogeneity of the object under study and the settings for the error (alpha), the power (beta), the effect size (ES), the number of replicate samples, and sample support, which is a feature that is often overlooked. The number of replicates, alpha, beta, ES, and sample support are interconnected. The effect of the sample support and its shape on the required number of replicate samples was investigated by means of a resampling method. The method was applied to a simulated distribution of Cd in the crown of a Salix fragilis L. tree. Increasing the dimensions of the sample support results in a decrease in the variance of the element concentration under study. Analysis of the variance is often the foundation of statistical tests, therefore, valid statistical testing requires the use of a fixed sample support during the experiment. This requirement might be difficult to meet in time-series analyses and long-term monitoring programs. Sample supports have their largest dimension in the direction with the largest heterogeneity, i.e. the direction representing the crown height, and this will give more accurate results than supports with other shapes. Taking the relationships between the sample support and the variance of the element concentrations in tree crowns into account provides guidelines for sampling efficiency in terms of precision and costs. In terms of time, the optimal support to test whether the average Cd concentration of the crown exceeds a threshold value is 0.405 m3 (alpha = 0.05, beta = 0.20, ES = 1.0 mg kg(-1) dry mass). The average weight of this support is 23 g dry mass, and 11 replicate samples need to be taken. It should be noted that in this case the optimal support applies to Cd under conditions similar to those of the simulation, but not necessarily all the examinations for this tree species, element, and hypothesis test.

Cadmium↗
PubMed2003

European concerted action on anticoagulation. Minimum numbers of lyophilized plasma samples for ISI calibration of CoaguChek and TAS point-of-care whole blood prothrombin time monitors.

International sensitivity index (ISI) calibration of whole blood prothrombin time (PT) monitors is too complex. We previously simplified the method by using European Concerted Action on Anticoagulation (ECAA) lyophilized plasma samples with the TAS PT-NC (Bayer AG, Leverkusen, Germany) and the CoaguChek Mini (Roche Diagnostics, Mannheim, Germany) whole blood PT monitoring systems. The TAS PT-NC required a correction derived from the line of equivalence. Monte Carlo bootstrap analysis of reducing numbers of test samples was performed with both systems. Plasma samples from patients receiving coumarin (coumarin samples), healthy subjects (normal samples), and plasma samples artificially depleted of coagulation factors were used. With the TAS PT-NC, 20 coumarin samples or 20 artificially depleted samples with 7 normal samples gave reliable ISI and international normalized ratio and satisfactory precision. With the CoaguChek Mini, 30 coumarin and 10 normal samples were required. Simplification of ISI calibration of the 2 monitoring systems is possible using fewer ECAA lyophilized plasma samples than the 80 required according to the World Health Organization guidelines for conventional PT systems and previously recommended for fresh plasma samples tested on the same 2 monitoring systems.

Animals↗