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Standard Precautions have been demonstrated to limit infection transmission in the healthcare setting. Despite their mandated use, adherence by healthcare professionals remains suboptimal. A nursing curriculum embedding infection prevention and control is essential in equipping future healthcare professionals with the skills and knowledge to improve patient safety. There are no psychometrically-validated tools that specifically assess influences on nursing students’ adherence to standard precautions.

ABSTRACTWe develop a method of designing CUSUM control charts that yields minimum sampling costs while meeting statistical constraints on the average time to signal when there is no assignable cause and the average time to signal when there is an assignable cause. We call this method statistical CUSUM design with minimum sampling costs. Numerical examples are given which show the dominance of this method over the usual statistical design method with the only disadvantage being the small additional effort to estimate sampling costs. The designs we compute are compared to recommended CUSUM statistical designs as well as economic statistical designs.

Facial skin defects created by Mohs micrographic surgery are commonly reconstructed using local cutaneous flaps from surrounding skin. To provide optimal survival and aesthetic outcomes, the cutaneous surgeon must command a thorough understanding of the complex vascular anatomy and physiology of the skin as well as the imperative physiologic and biomechanical considerations when elevating and transferring tissue via local skin flaps.

A robust optical fibre based CO2exhaust gas sensor operating in the mid infrared spectral range is described. It is capable of detecting on board carbon dioxide (CO2) emissions from both diesel and petrol engines. The optical fibre sensor is not cross sensitive to other gaseous species in the exhaust such as water vapour (H2O), carbon monoxide (CO), oxides of nitrogen (NOx) or oxides of sulphur (SOx).The response of the sensor to carbon dioxide present in the exhaust of Fiat Croma diesel engine are presented.

Problem: We present a case study concerned with the problem of reducing errors by vendors who process credit card applications for a large credit card bank. More specifically, we show the results of a process performance evaluation and process capability analysis that was used to help identify and solve the problem of excess variability. These tasks are sometimes called Phase I studies. We conclude with a discussion of implications for process monitoring and subsequent process improvements, sometimes called Phase II studies.Approach: Quality of the credit card processing task was measured with count data and the counts were low; this is typical of many service operations today. Our approach was to use sequence plots and CUSUM sequence plots of the data and Shewhart npand CUSUM control charts to explore the count data drawn from the four vendors that process credit card applications for this bank. We found that using both Shewhart and CUSUM methods helped us to better accomplish the Phase I study.Results: The results of our analysis indicated differences in quality between vendors and within vendors over time. Subsequent analysis showed that the differences were related directly to training and workers' experience. Two interventions were made subsequent to the process capability analysis; these were improved training and interventions to reduce turnover.

This paper discusses how to run 2kexperiments for process improvement when there is one hard-to-change factor. The paper studies the different ways of running these experiments and gives practical recommendations. It shows how to block designs to get small prediction variance and low cost. It presents an algorithm to allow the selection of efficient blocking relations, in 2kdesigns, where there is one hard-to-change factor and tabulates the results for 23to 27designs, in various block sizes. It presents methods for calculating the prediction variance and G-efficiency when there are hard-to-change factors. The calculations are demonstrated by applying them to 2kdesigns, and results are tabulated for various block sizes. We show that optimally blocked split-plot designs dominate randomized designs. A blocked split-plot design is both less expensive to run, because it requires fewer resets of the hard-to-change factor, and more precise, as it gives a lower variance of prediction than a completely randomized design.

In this paper, we compare the costs of an economically designed CUSUM control chart and a common Shewhart control chart, the X–bar chart for many configurations of parameters. Our results indicate that there are identifiable regions where there is an overwhelming cost advantage to using CUSUM charts. Additionally, we find that there are identifiable regions where an X–bar chart can be employed without any substantial economic disadvantage. Finally, we identify regions where a regular search policy is less costly than a policy of using either a CUSUM or X–bar chart.

In industry, the run order of experiments is often randomized, but this does not guarantee that all factor levels are reset from one run to the next. When this happens and the levels of factors are the same in successive runs, the assumption of independent observations from run to run may be violated or incorrect. In this case, an ordinary least squares analysis can produce biased estimates of the coefficients in the model, which leads to erroneous test results and inferences.In this paper we describe how not resetting the levels of one or more factors in successive runs can result in less precision in parameter estimates and a larger than expected prediction variance. We present formulas for the prediction variance and the expected prediction variance for this situation. These quantities are important because they allow us to compare the prediction properties of experiments that are completely randomized to experiments where the levels of one or more factors are not reset. We give an analysis of an industrial experiment of this type and recommendations for carrying out factorial experiments where the levels of one or more factors are not reset.

Experimental factors, especially when they are hard-to-change, are often not independently reset on each run. For example, it would be very costly to let a mold cool down between runs and then reheat it when the same mold temperature is required on successive runs. Therefore, even when the experiment is run using a random run order, a “completely randomized design” requiring a single error term is not obtained. There is a restriction on randomization that causes the experiment to require more than one error term in the model. The analysis of the experiment with restricted randomization often proceeds, however, as if a completely randomized design were run. This ignores the fact that the experiment inherently has a “split plot” structure. We examine properties of experiments run in this very common manner and investigate Lkexperiments using two error terms. One error term is associated with setting the “hard-to-change factors” and the other represents the remaining error. We develop the expected covariance matrices for observations and for the estimated regression coefficients in experiments using a random run order and using run orders that restrict randomization partially or completely. We compare the precision of the estimators of the regression coefficients for the various run order scenarios and show that classical split-plot blocking is superior to a random run order.

Abstract: Solidification of eutectic Sn-Ag solder, with and without Cu6Sn5 composite reinforcements, on copper substrates, was investigated at two different cooling rates. The size, orientation, randomness, and overall morphology of the dendritic microstructure were examined as a function of cooling rate. Cu6Sn5 particle reinforcements were found to act as nucleation sites for dendrites, in addition to sites on the substrate/solder interface. The mechanical properties of these solders were also examined as a function of cooling rate. Solder joints with a lower load-carrying area were found to exhibit higher shear strength, but reduced ductility when compared to solder joints with more load carrying area.

Background Psoriasis impairs health-related quality of life (HRQoL).Objective To improve understanding of flare burden in patients with moderate to severe psoriasis.Methods A retrospective, cross-sectional study comparing data in U.S. patients with and without psoriasis flares. Physicians identified flaring patients as those not in remission, or in remission < 12 weeks, with worsening/unstable disease progression.Results Overall health status (EQ-5D-3L) was reduced in flaring versus matched non-flaring patients (P= .001); this difference was clinically meaningful (> 0.074 difference in absolute value). Reduced HRQoL and activity impairment, measured by Dermatology Life Quality Index (P= .0178) and Work Productivity and Activity Impairment Questionnaire (P= .0002), respectively, were observed in flaring versus non-flaring patients. Anxiety was associated with flaring (P= .0139). Flaring patients were less satisfied with treatment effectiveness than non-flaring patients (P< .0001). The flaring group experienced a median of two flares over 12 months.Conclusion Flares are associated with reduced health status and HRQoL and lower treatment satisfaction.

The effect of analytical error on the interpretation of blood lead data obtained from population studies is discussed. Statistical analysis of measured blood lead values reported in four representative population studies shows over 40 percent of the variability in blood lead measurements is due to analytical error. Because of this analytical error, a large percentage of the observed blood lead measurements which exceed a threshold limit are “false positives” in that the true blood lead values for these individuals do not exceed the threshold. The EPA has suggested that the distribution of blood lead values could be used as a guide for determining the portion of a population at risk. “At risk” is defined as having blood lead values above a certain threshold. If this is done, the effect of analytical error which causes “false positives” should be considered properly to obtain an accurate estimate of the population at risk.

The National Ocean Service (NOS) has been pursuing the application of kinematic Global Positioning System (GPS) positioning to airborne instrumentation packages and photogrammetry in particular. Two partially successful experiments demonstrate the differential carrier‐phase observations acquired by a GPS receiver aboard the airplane can support very precise aerotriangulation without any ground control. In these experiments aerial photography over an area of abundant ground control is acquired simultaneously with an uninterrupted set of differential GPS observations. The photogrammetric image data are employed in two aerotriangulation adjustments, one with the ground control, the other with only the GPS data. In both experiments, the rms of the discrepancies between the camera positions computed by the two adjustments is just over 5 cm in each coordinate. Discrepancies in the computed ground points are even smaller, but this is due in part to the large scale of the photography (1:3,000).

A standard CUSUM control scheme and four modified CUSUM control schemes are evaluated for robustness. The average run length (ARL) for each scheme is evaluated using a contaminated normal distribution, a distribution that has longer tails than the normal. A CUSUM control scheme that ignores the first suspected outlier, but gives an out-of-control signal for two successive outliers is found to perform well.

Procedures with shift detection in a two-way array are presented. Maximum likelihood estimates are derived when a single shift has occurred and a test of significance is constructed. A sequential maximum likelihood procedure is proposed to detect multiple shifts. The maximum likelihood procedure is contrasted with the CUSUM approach and simulation results are presented. In a manufacturing example, the columns could be time and the rows, machines of the same type. The maximum likelihood approach yields an unbiased estimate of variability and is powerful, especially in the presence of large column variability.

The idea of using non-constant sampling intervals has been of interest in quality control applications since it was first suggested for the "skip-lot sampling plan" of Dodge. Recent interest has focused on the use of variable sampling interval (VSI) control schemes. VSI control schemes use a short sampling interval is given

Cumulative Sum (CUSUM) quality control schemes are becoming widely used i n industry because they are powerful, versatile, and easy to use. They cumulate recent process data to quickly detect out-of-control situations. They also serve as a powerful diagnostic tool. There are now more than 10,000 CUSUM control schemes in use daily in Du Pont. This paper describes design and implementation procedures for CUSUM control schemes with emphasison properties that are recorded as counts. The paper will describe recent developments which make CUSUM procedures more useful and more powerful.The recent developments described are: Fast Initial Response (FIR) CUSUM which gives extra sensitivity to out-of-control situations at start up or after a(possiblyin effective)control action.A Combined She whart-CUSUM which combines the key featuresof CUSUM schemes and She whart Schemes by adding She whart Control Limits to a CUSUM scheme.ROBUST CUSUM schemes which are no tunduly influenced by a few outliers or fliers occurring in the stream of data.The philosophy of continual improvement of aprocessisvery compatible with CUSUM procedures.As CUSUM procedures give much more responsive control,a CUSUM signal does notmean that the process is producing bad product.Rather it means that action should be taken sothat the process does not produce bad product.

The effects of water-induced physical and chemical property modification on a graphite/epoxy (GrEp) laminate were investigated. The laminate was consolidated using unidirectional 1300/934 graphite/epoxy prepreg. Specimens were conditioned, hydrothermally, by immersion in distilled water at 45, 60, 75 and 90'C for more than 9000 hours. The composite properties were characterized by evaluating the specimen's weight change due to water absorption and desorption, by hygrothermally induced expansion, and by water-induced change of the glass transition temperature (T,). Optical microscopy and scanning electron microscopy (SEM) were conducted to assess surface modification associated with resin cracking and resin mass loss. Water sorption in the Gr/Ep material exhibited both Fickian and non-Fickian diffusion behavior. Diffusion data showed that the time for the onset of non-Fickian behavior was inversely related to the increase in exposure temperature. Anomalous (i.e., non-Fickian) behavior in the composite resulted from both chemical modification and physical damage to the epoxy resin. Moisture-induced cracks, voids, and surface resin peeling were revealed by SEM and optical microscopy. Surface cracking and resin mass loss phenomena were used to describe water sorption behavior in composites. Thermomechanical analysis (TMA), water desorption, and infrared (IR) spectral results suggest that water retention in the composite can be characterized: (1) by water trapped at defects such as crack tips, interfaces, and voids; (2) by water interaction associated with weak hydrogen bonding within the resin; and (3) by water bonded to hydrophilic functional groups of the polymer chains.

It is fairly common in the conduct of an experiment to randomize, either completely or partially (within a block), the allocation of treatments to experimental units. The act of randomization is easy to envision in experiments that require an equal chance for every experimental unit, independent of other units, to receive any treatment. How does one randomize, however, factorial experiments that involve factors having more than one level? The practice in industry has been to obtain at random the sequence of allocating treatment combinations to experimental units. The analyses then proceed assuming the design to be properly randomized. Using only a random run order, however, does not render a randomized experiment as conceived by Fisher. A factor that requires the same level for successive runs may not be independently reset from run-to-run. An experiment therefore becomes a (unbalanced) split-plot experiment due to the restriction imposed on randomization of not resetting factor levels for every run. We make a distinction, not made explicitly in the literature, between designs that use a random run order and those that randomize (completely). Independent error terms are not obtained when data have been collected from a random run order. We quantify the bias in results for designs that use a random run order but assume complete randomization. Data generated from a laboratory experiment on crude oils, analyzed first by Hader and Grandage (1956), and later by Daniel and Wood (1971), illustrate the effect of not recognizing the restrictions on randomization. Some recommendations are made for designing experiments when it is not practical to reset factor levels.

Controlling the gonorrhea epidemic in the United States will depend on good clinical management of individual infected patients. The diagnoses of Neisseria gonorrhoeaeinfections can best be made with culture using Thayer-Martin selective medium or a new transport medium, Transgrow, if optimal technics for obtaining and handling culture specimens are used. The reason for therapy failure in many cases is not the development of partially resistant gonococcal isolates, but the use of ineffective antibiotics as well as inadequate dosage. A survey of recent studies documents that adequate doses of procaine penicillin with probenecid or tetracycline remain effective therapy for acute N gonorrhoeaeinfection.

The development of the fluorescent treponemal antibody-absorption (FTA-ABS) test1 has been the result of continued attempts to improve the original FTA procedures,2,3 in terms of sensitivity and specificity. Test improvement was made possible by the discovery that nonpathogenic treponemes such as Treponema microdentium and the Reiter treponeme share antigens in common with T pallidum, and the corresponding common antibodies are of frequent occurrence in serums from normal individuals. It was found, however, that such antibodies could be removed from test serums by intact Reiter treponeme absorption and that in serums so treated and subsequently examined there was an increased specificity and sensitivity of test results.4 Later, the use of sonic-disrupted Reiter treponemes in place of intact organisms for absorption was described, the resulting procedure being identified as the FTA-ABS test.1 At present, a stable water-soluble extract from Reiter treponemes is employed instead of sonicate. This change

The Venereal Disease Branch, Center for Disease Control, in a cooperative study has reevaluated the comparative efficacy of antibiotic schedules for the treatment of early syphilis in 586 patients. All parenteral penicillin, tetracycline, and erythromycin treatment schedules recommended by the Public Health Service were studied. Erythromycin in base form, 20 gm, was given in a divided-dose schedule over a ten-day period. Subsequently, the dose of erythromycin had to be raised to 30 gm because of a high failure rate. All penicillin schedules tested showed a satisfactory cure rate with a cumulative re-treatment rate of only 10% in the 24-month observation period. The 30-gm schedule of erythromycin base proved as effective as tetracycline and penicillin G.

Since the isolation of a strain of Cephalosporium acremonium by Brotzu in 1945,1 the recovery of seven natural antibiotic substances from this fungus has been reported.2 One of these antibiotic substances is cephalosporanic acid.3 This nucleus is chemically closely related to the penicillin nucleus, 6-aminopenicillanic acid, differing by having a fused dihydrothiazine B lactam ring, rather than a fused thiazolidine B lactam ring.4 Synthetic manipulation of the 7-aminocephalosporin nucleus by Chauvette et al5 has resulted in the development of cephalothin (Keflin), now available commercially in the United States.A second important derivative, cephaloridine, chemically 7-[α-(2-Thienyl) acetamido]-3-(1-pyridylmethyl)-3-cephem-4-carboxylic acid betaine, has been produced in England and has been the subject of several favorable clinical reports from that country.6,7Cephaloridine has essentially the same spectrum of antimicrobial activity as cephalothin, but is more potent against gram-positive organisms. Generally, the pharmacological properties of the two drugs are similar.

The epidemiologic control of syphilis would be greatly enhanced if gonorrhea therapy were simultaneously curative for incubating syphilis. In a cooperative study, schedules currently recommended by the Public Health Service for gonorrhea treatment in the male and female (aqueous penicillin G procaine, 2.4 and 4.8 million units, respectively) were evaluated in 127 patients exposed to infectious syphilis within a 30-day period. After a three-month clinical and serologic follow-up, these schedules were found to be 100% effective in aborting incubating syphilis. Of a control group of contacts treated with placebo who were exposed to infectious syphilis within 30 days preceding treatment, 30% developed syphilis. Consequently, aqueous penicillin G procaine in the dosage of 2.4 and 4.8 million units is curative therapy for patients with gonorrhea with coexisting incubating syphilis.