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Democratic representation and apportionment: quantitative principles underlying apportionment methods.

L Papayanopoulos
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L Papayanopoulos. 1973-11-09. Democratic representation and apportionment: quantitative principles underlying apportionment methods.. https://doi.org/10.1111/j.1749-6632.1973.tb41397.x

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PubMed1996

Manual versus computer-automated semen analyses. Part I. Comparison of counting chambers.

OBJECTIVE: To determine the accuracy and precision of counting chambers analyzed manually and with a computer-automated semen analyzer (CASA; Hamilton-Thorne Research, Beverly, MA). DESIGN: Prospective study using comparative measurements of sperm concentration, motility and concentration of latex beads with three types of counting chambers: hemacytometers, 12 and 20 MicroCell (Conception Technologies, Inc., La Jolla, CA) Chambers, and Makler (Sefi-Medical Instruments, Haifa, Israel) Chambers. SETTING: A hospital-based Andrology laboratory. PATIENTS: Male partners of couples undergoing infertility evaluation. MAIN OUTCOME MEASURES: Experiment I: measurements of sperm concentration were evaluated within hemacytometers; Experiment II: measurements of sperm concentration in the 35 to 50 x 10(6)/mL range and sperm motility were determined using a known concentration of beads. RESULTS: Experiment I: differences were demonstrated within two of eight hemacytometers (side 1 versus side 2): however, no significant effect of hemacytometer on variation in sperm concentration measurements was observed. Experiment II: CASA-analyzed 20 MicroCell Chambers demonstrated the best precision for sperm concentration (intraclass correlation coefficient = 0.93) and motility (intraclass correlation coefficient = 0.88). Experiment III: 20 MicroCell Chambers most accurately determined known bead concentration (35 +/- 5 x 10(6)/mL) whether analyzed on CASA (34.9 x 10(6)/mL) or manually (35.2 x 10(6)/mL). CONCLUSIONS: 20 MicroCell Chambers proved to be accurate and precise for determining concentration and motility of semen specimens whether analyzed manually or with CASA.

Computers↗
PubMed1996

Manual versus computer-automated semen analyses. Part II. Determination of the working range of a computer-automated semen analyzer.

OBJECTIVE: To determine the accuracy and precision of a computer-automated semen analyzer (CASA; Hamilton-Thorne Research, Beverly, MA) over a wide range of sperm concentrations. DESIGN: Prospective study using comparative measurements of sperm concentration and motility were performed using manual and CASA methods of analyses. SETTING: A hospital-based Andrology laboratory. PATIENTS: Male partners of couples undergoing infertility evaluation. MAIN OUTCOME MEASURES: Measurements of sperm concentration in the range of 1 to 200 x 10(6)/mL were performed using hemacytometers and CASA-analyzed 20 MicroCell counting chambers (Conception Technologies, Inc., La Jolla, CA). Accuracy was assessed by comparison to the hemacytometer ("gold standard"). The MicroCell counting chambers also were used for manual and CASA sperm motility determinations. RESULTS: The CASA-analyzed 20 Microcell Chamber most precisely determined sperm concentration in the 1 to 200 x 10(6)/mL range (intraclass correlation coefficient = 0.94). The hemacytometer was least precise (intraclass correlation coefficient = 0.91). There was a high degree of correlation between the manually and CASA-analyzed MicroCell Chambers in the sperm concentration range of 20 to 149 x 10(6)/mL. Above and below this range, correlation was lower. Motility was determined most precisely using the CASA-analyzed 20 MicroCell Chamber. CONCLUSIONS: The Hamilton-Thorne CASA used with the 20 MicroCell Chamber is a precise and accurate method for determining sperm concentration and motility of semen specimens with concentrations in the 20 to 149 x 10(6)/mL range. This same combination of CASA and MicroCell Chamber provides precise sperm motility results.

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