Application of multivariate statistical process control to fuel cell manufacturing

Univariate statistical control charts, such as the Shewhart chart, do not satisfy the requirements for process monitoring on a high volume automated fuel cell manufacturing line. This is because of the number of variables that require monitoring. The risk of elevated false alarms, due to the nature of the process being high volume, can present problems if univariate methods are used. Multivariate statistical methods are discussed as an alternative for process monitoring and control. The research presented is conducted on a manufacturing line which evaluates the performance of a fuel cell. It has three stages of production assembly that contribute to the final end product performance. The product performance is assessed by power and energy measurements, taken at various time points throughout the discharge testing of the fuel cell. The literature review performed on these multivariate techniques are evaluated using individual and batch observations. Modern techniques using multivariate control charts on Hotellings T2 are compared to other multivariate methods, such as Principal Components Analysis (PCA). The latter, PCA, was identified as the most suitable method. Control charts such as, scores, T2 and DModX charts, are constructed from the PCA model. Diagnostic procedures, using Contribution plots, for out of control points that are detected using these control charts, are also discussed. These plots enable the investigator to perform root cause analysis. Multivariate batch techniques are compared to individual observations typically seen on continuous processes. Recommendations, for the introduction of multivariate techniques that would be appropriate for most high volume processes, are also covered.

Nota sobre ácaros (Acari) atacando fruteira-do-conde (Rollinia sp.)

The flowers of this orchard tree presents six fleshy petals, fused two by two, and disposed propeller like. In the center is a cavity which harbors the cone shaped reproductive organs. An eriophyid mite, described by H. H. Keifer as Aculops flechtmann Keifer, 1972, causes considerable bronzing to the petals (Fig. 1-A). Large numbers of this mite attacking the basis of the reproductive organs causes them to dry and drop. On the young fruits, which are squamous, this mite causes some rusting and small necrotic areas (Fig. 1-B). As the fruit grows these small areas remain dark and barky. Very often the necrotic areas are invaded by the false spider mite Brevipalpus phoenicis (Geijskes, 1939), which enlarges the damage. The false spider mite also attacks leaves and green stems; the epidermis of the latter then assumes a barky appearance.

Fermentação da gelose pelas bacterias anaerobias

1 - Anaerobic bacteria of the Clostridium genus acidify mineral media without when agar is added. 2 - Acidulation results from the attack on the agar as a source of carbon. 3 - The quantity of CO² produced by the decomposition of the agar is approximately that obtained with soil bacteria as shown by Waksmann and Diehm working with hemicelluloses. Although galactone is less atacked than the other hemicelluloses the acidity produced is sufficient to disturb the fermentation tests in semi-solid media with agar. 4 - The acidulation of Spray's sugar-free control medium is probably due to the decomposition of the agar by anaerobes. The acidity produced may interfere with the acidity of the fermentation of the sugar in Spray's test or may be added to it, thus giving a false indication of the real acidity.

Tratamento eclético da lepra: 20 anos de experiência

The author gives the clinical records of 20 patients, 14 of which were treated during 17 months, and the rest much less. The method used for treatment was the ecclectical — preferred by the A. since many years —, in which he associates electricity with minor surgery, chaulmestrol (pure or with 0.5 p. c. iodine or 4 p. c. creosote) and other auxilliary curative agents. The chaulmoogra derivatives were used daily as nostrils tamponage (2 p.c. mentholated or thymolated ester), periodically by injections inside the enlarged lymph nodes and nerve abscesses, and twice weekly by subcutaneous infiltrations (MUIR method) 5 c.c. each, and chaulmoogra soap tablets per os. The galvanocauterisation session was once per week, on active leprotic lesions, followed by painting with 30 p. c. trichloracetic acid solution. All 20 patients were bacilliferous before treatment, and became stronger positive after some months treatment. At the end 14 negativated and 6 remained positive and sometimes bacilli being very scanty. 16 out of 20 gave interesting serological reactions, viz.: Wassermann, Stern, Kahn. Rubino, Witebsky and Gaté (Formol-gel) positive in 5; Stern, Rubino. Witebsky and Gaté positive and Wassermann and Kahn negative in 2; Stern. Kahn, Witebsky and Gaté positive and Wassermann anticomplementary in 1; Wassermann. Stern, Kahn, Rubino and Gaté negative in 1. in the beginning, and a few months later Stern. Witebsky and Gaté becoming positive; Stern. Rubino. Witebsky and Gaté positive and anticomplementary W. in 1; Stern, Witebsky and Gaté positive and Wassermann. Kahn and Rubino negative in 1; Witebsky and Gaté positive and Wassermann, Stern, Kahn and Rubino negative in 1; Witebsky 3 times anticomplemantary and strongly positive Gaté in 1; Wassermann and Gaté positive in 1; Stern and Rubino positive in 1 and Stern test negative in one. In 7 cases high Formol-gel were associated with a high sedimentation index. Many cases had very high S.I. being a false measure of the severity of the disease; others remained very high notwithstanding the great improvement of the disease. All patients with more than 12 months treatment became practically symptom free. Lepra reaction amongst them was rare and always started by embolic rash, being controlled by destruction of such skin lesions by galvanocauterisation. In a few cases the lepromata infiltrated with "Subintrol" (a 3 p. c. special chaulmoogra soap prepared by Dr. ASTROGILDO MACHADO) were completely destroyd and never relapsed. In October 1946 Dr. ERNEST MUIR saw here a few cases treated by the author's method and suggested the combination of Diasone with galvanocauterisation which is being done now with satifactory results. The second part of this paper, reporting many leprosy cases treated by the so-called ecclectical method, which are symptom free and negativated since five to ten years, will be published as soon as the sulfone-therapy be summarised in some reliable scientific report to be compared with.

A note on reproduction of Didelphis marsupialis in captivity

Conditions leading to successful reproduction of Didelphis marsupialis in captivity are described. A trial involving four mating pairs which had been maintained at least four months in the laboratory resulted in three litters and one false pregnancy. This is, to our knowledge, the first record of successful breeding of this species in captivity.

Studies in search of a suitable experimental insect model for xenodiagnosis of hosts with Chagas' disease: 2 - Attempts to upgrade the reliability and the efficacy of xenodiagnosis in chronic Chagas' disease

In order to upgrade the reliability of xenodiagnosis, attention has been directed towards population dynamics of the parasite, with particular interest for the following factors: 1. Parasite density which by itself is not a research objective, but by giving an accurate portrayal of parasite development and multiplication, has been incorporated in screening of bugs for xenodiagnosis. 2. On the assumption that food availability might increase parasite density, bugs from xenodiagnosis have been refed at biweekly intervals on chicken blood. 3. Infectivity rates and positives harbouring large parasite yields were based on gut infections, in which the parasite population comprised of all developmental forms was more abundant and easier to detect than in fecal infections, thus minimizing the probability of recording false negatives. 4. Since parasite density, low in the first 15 days of infection, increases rapidly in the following 30 days, the interval of 45 days has been adopted for routine examination of bugs from xenodiagnosis. By following the enumerated measures, all aiming to reduce false negative cases, we are getting closer to a reliable xenodiagnostic procedure. Upgrading the efficacy of xenodiagnosis is also dependent on the xenodiagnostic agent. Of 9 investigated vector species, Panstrongylus megistus deserves top priority as a xenodiagnostic agent. Its extraordinary capability to support fast development and vigorous multiplication of the few parasites, ingested from the host with chronic Chagas' disease, has been revealed by the strikingly close infectivity rates of 91.2% vs. 96.4% among bugs engorged from the same host in the chronic and acute phase of the disease respectively (Table V), the latter comporting an estimated number of 12.3 x 10[raised to the power of 3] parasites in the circulation at the time of xenodiagnosis, as reported previously by the authors (1982).

A novel gene expression signature in peripheral blood mononuclear cells for early detection of colorectal cancer.

BACKGROUND: Early detection and treatment of colorectal adenomatous polyps (AP) and colorectal cancer (CRC) is associated with decreased mortality for CRC. However, accurate, non-invasive and compliant tests to screen for AP and early stages of CRC are not yet available. A blood-based screening test is highly attractive due to limited invasiveness and high acceptance rate among patients. AIM: To demonstrate whether gene expression signatures in the peripheral blood mononuclear cells (PBMC) were able to detect the presence of AP and early stages CRC. METHODS: A total of 85 PBMC samples derived from colonoscopy-verified subjects without lesion (controls) (n = 41), with AP (n = 21) or with CRC (n = 23) were used as training sets. A 42-gene panel for CRC and AP discrimination, including genes identified by Digital Gene Expression-tag profiling of PBMC, and genes previously characterised and reported in the literature, was validated on the training set by qPCR. Logistic regression analysis followed by bootstrap validation determined CRC- and AP-specific classifiers, which discriminate patients with CRC and AP from controls. RESULTS: The CRC and AP classifiers were able to detect CRC with a sensitivity of 78% and AP with a sensitivity of 46% respectively. Both classifiers had a specificity of 92% with very low false-positive detection when applied on subjects with inflammatory bowel disease (n = 23) or tumours other than CRC (n = 14). CONCLUSION: This pilot study demonstrates the potential of developing a minimally invasive, accurate test to screen patients at average risk for colorectal cancer, based on gene expression analysis of peripheral blood mononuclear cells obtained from a simple blood sample.

Rare genomic structural variants in complex disease: lessons from the replication of associations with obesity.

The limited ability of common variants to account for the genetic contribution to complex disease has prompted searches for rare variants of large effect, to partly explain the 'missing heritability'. Analyses of genome-wide genotyping data have identified genomic structural variants (GSVs) as a source of such rare causal variants. Recent studies have reported multiple GSV loci associated with risk of obesity. We attempted to replicate these associations by similar analysis of two familial-obesity case-control cohorts and a population cohort, and detected GSVs at 11 out of 18 loci, at frequencies similar to those previously reported. Based on their reported frequencies and effect sizes (OR≥25), we had sufficient statistical power to detect the large majority (80%) of genuine associations at these loci. However, only one obesity association was replicated. Deletion of a 220 kb region on chromosome 16p11.2 has a carrier population frequency of 2×10(-4) (95% confidence interval [9.6×10(-5)-3.1×10(-4)]); accounts overall for 0.5% [0.19%-0.82%] of severe childhood obesity cases (P = 3.8×10(-10); odds ratio = 25.0 [9.9-60.6]); and results in a mean body mass index (BMI) increase of 5.8 kg.m(-2) [1.8-10.3] in adults from the general population. We also attempted replication using BMI as a quantitative trait in our population cohort; associations with BMI at or near nominal significance were detected at two further loci near KIF2B and within FOXP2, but these did not survive correction for multiple testing. These findings emphasise several issues of importance when conducting rare GSV association, including the need for careful cohort selection and replication strategy, accurate GSV identification, and appropriate correction for multiple testing and/or control of false discovery rate. Moreover, they highlight the potential difficulty in replicating rare CNV associations across different populations. Nevertheless, we show that such studies are potentially valuable for the identification of variants making an appreciable contribution to complex disease.

Prognostic value of sentinel node biopsy in 327 prospective melanoma patients from a single institution

AIM: To confirm the accuracy of sentinel node biopsy (SNB) procedure and its morbidity, and to investigate predictive factors for SN status and prognostic factors for disease-free survival (DFS) and disease-specific survival (DSS). MATERIALS AND METHODS: Between October 1997 and December 2004, 327 consecutive patients in one centre with clinically node-negative primary skin melanoma underwent an SNB by the triple technique, i.e. lymphoscintigraphy, blue-dye and gamma-probe. Multivariate logistic regression analyses as well as the Kaplan-Meier were performed. RESULTS: Twenty-three percent of the patients had at least one metastatic SN, which was significantly associated with Breslow thickness (p<0.001). The success rate of SNB was 99.1% and its morbidity was 7.6%. With a median follow-up of 33 months, the 5-year DFS/DSS were 43%/49% for patients with positive SN and 83.5%/87.4% for patients with negative SN, respectively. The false-negative rate of SNB was 8.6% and sensitivity 91.4%. On multivariate analysis, DFS was significantly worsened by Breslow thickness (RR=5.6, p<0.001), positive SN (RR=5.0, p<0.001) and male sex (RR=2.9, p=0.001). The presence of a metastatic SN (RR=8.4, p<0.001), male sex (RR=6.1, p<0.001), Breslow thickness (RR=3.2, p=0.013) and ulceration (RR=2.6, p=0.015) were significantly associated with a poorer DSS. CONCLUSION: SNB is a reliable procedure with high sensitivity (91.4%) and low morbidity. Breslow thickness was the only statistically significant parameter predictive of SN status. DFS was worsened in decreasing order by Breslow thickness, metastatic SN and male gender. Similarly DSS was significantly worsened by a metastatic SN, male gender, Breslow thickness and ulceration. These data reinforce the SN status as a powerful staging procedure

Prognostication of neurologic outcome in cardiac arrest patients after mild therapeutic hypothermia: a meta-analysis of the current literature.

PURPOSE: To assess the sensitivity and false positive rate (FPR) of neurological examination and somatosensory evoked potentials (SSEPs) to predict poor outcome in adult patients treated with therapeutic hypothermia after cardiopulmonary resuscitation (CPR). METHODS: MEDLINE and EMBASE were searched for cohort studies describing the association of clinical neurological examination or SSEPs after return of spontaneous circulation with neurological outcome. Poor outcome was defined as severe disability, vegetative state and death. Sensitivity and FPR were determined. RESULTS: A total of 1,153 patients from ten studies were included. The FPR of a bilaterally absent cortical N20 response of the SSEP could be calculated from nine studies including 492 patients. The SSEP had an FPR of 0.007 (confidence interval, CI, 0.001-0.047) to predict poor outcome. The Glasgow coma score (GCS) motor response was assessed in 811 patients from nine studies. A GCS motor score of 1-2 at 72 h had a high FPR of 0.21 (CI 0.08-0.43). Corneal reflex and pupillary reactivity at 72 h after the arrest were available in 429 and 566 patients, respectively. Bilaterally absent corneal reflexes had an FPR of 0.02 (CI 0.002-0.13). Bilaterally absent pupillary reflexes had an FPR of 0.004 (CI 0.001-0.03). CONCLUSIONS: At 72 h after the arrest the motor response to painful stimuli and the corneal reflexes are not a reliable tool for the early prediction of poor outcome in patients treated with hypothermia. The reliability of the pupillary response to light and the SSEP is comparable to that in patients not treated with hypothermia.

Individual versus group strategy-proofness: when do they coincide?

A social choice function is group strategy-proof on a domain if no group of agents can manipulate its final outcome to their own benefit by declaring false preferences on that domain. Group strategy-proofness is a very attractive requirement of incentive compatibility. But in many cases it is hard or impossible to find nontrivial social choice functions satisfying even the weakest condition of individual strategy-proofness. However, there are a number of economically significant domains where interesting rules satisfying individual strategy-proofness can be defined, and for some of them, all these rules turn out to also satisfy the stronger requirement of group strategy-proofness. This is the case, for example, when preferences are single-peaked or single-dipped. In other cases, this equivalence does not hold. We provide sufficient conditions defining domains of preferences guaranteeing that individual and group strategy-proofness are equivalent for all rules defined on the

Is MDCT enough reliable for the evaluation of acute colitis including the underlying etiology? : correlation with colonoscopy and pathology : P2

Purpose: 1. To assess the diagnostic value of MDCT for acute colitis of various origin confirmed by colonoscopy and histology. 2. To evaluate the accuracy of MDCT of making the correct differential diagnosis. Methods and materials: The electronic hospital database from January 2006 to August 2008 revealed 351 patients with acute colitis of any origin wdetected by colonoscopy. In 85 out of these patients MDCT had been simultaneously performed (delay 3.1 days). Two radiologists jointly reviewed their corresponding CT features without knowledge of pathology and correlated them with the final histological diagnosis. Results: Eighty patients were finally included (46 women, mean age 63.4). Colitis was of ischemic (n = 35, 44%) or infectious (n = 15, 19%) origin. 18 patients (23%) had acute ulcerative colitis or Crohn's disease, in 10 patients (12%) another inflammatory cause and in two patients (2%) post radiation colitis was proven. MDCT was positive in 63 patients (78.9%). In 11 out of the 17 negative MDCT, the examination had been performed without large bowel distention. Ischemic colitis was responsible for 47.1% of the negative MDCT. Correct differential diagnosis was made in 32 (50.7%) out of the 63 positive MDCT. Among the different etiologies, the ischemic colitis was the most often misdiagnosed cause (n = 17, 58.6%). Conclusion: Large bowel distension is mandatory for reliable MDCT detection of acute colitis of any origin. Among the different aetiologies the ischemic cause is the most often associated with false negative MDCT findings and, in case of positive features, the most difficult to recognize as such.

Pareto or log-normal? A recursive-truncation approach to the distribution of (all) cities

Traditionally, it is assumed that the population size of cities in a country follows a Pareto distribution. This assumption is typically supported by nding evidence of Zipf's Law. Recent studies question this nding, highlighting that, while the Pareto distribution may t reasonably well when the data is truncated at the upper tail, i.e. for the largest cities of a country, the log-normal distribution may apply when all cities are considered. Moreover, conclusions may be sensitive to the choice of a particular truncation threshold, a yet overlooked issue in the literature. In this paper, then, we reassess the city size distribution in relation to its sensitivity to the choice of truncation point. In particular, we look at US Census data and apply a recursive-truncation approach to estimate Zipf's Law and a non-parametric alternative test where we consider each possible truncation point of the distribution of all cities. Results con rm the sensitivity of results to the truncation point. Moreover, repeating the analysis over simulated data con rms the di culty of distinguishing a Pareto tail from the tail of a log-normal and, in turn, identifying the city size distribution as a false or a weak Pareto law.

Structured RNAs in the ENCODE selected regions of the human genome.

Functional RNA structures play an important role both in the context of noncoding RNA transcripts as well as regulatory elements in mRNAs. Here we present a computational study to detect functional RNA structures within the ENCODE regions of the human genome. Since structural RNAs in general lack characteristic signals in primary sequence, comparative approaches evaluating evolutionary conservation of structures are most promising. We have used three recently introduced programs based on either phylogenetic-stochastic context-free grammar (EvoFold) or energy directed folding (RNAz and AlifoldZ), yielding several thousand candidate structures (corresponding to approximately 2.7% of the ENCODE regions). EvoFold has its highest sensitivity in highly conserved and relatively AU-rich regions, while RNAz favors slightly GC-rich regions, resulting in a relatively small overlap between methods. Comparison with the GENCODE annotation points to functional RNAs in all genomic contexts, with a slightly increased density in 3'-UTRs. While we estimate a significant false discovery rate of approximately 50%-70% many of the predictions can be further substantiated by additional criteria: 248 loci are predicted by both RNAz and EvoFold, and an additional 239 RNAz or EvoFold predictions are supported by the (more stringent) AlifoldZ algorithm. Five hundred seventy RNAz structure predictions fall into regions that show signs of selection pressure also on the sequence level (i.e., conserved elements). More than 700 predictions overlap with noncoding transcripts detected by oligonucleotide tiling arrays. One hundred seventy-five selected candidates were tested by RT-PCR in six tissues, and expression could be verified in 43 cases (24.6%).

Optimal Universal and Categorical Benefits with Classification Errors and Imperfect Enforcement

We determine he optimal combination of a universal benefit, B, and categorical benefit, C, for an economy in which individuals differ in both their ability to work - modelled as an exogenous zero quantity constraint on labour supply - and, conditional on being able to work, their productivity at work. C is targeted at those unable to work, and is conditioned in two dimensions: ex-ante an individual must be unable to work and be awarded the benefit, whilst ex-post a recipient must not subsequently work. However, the ex-ante conditionality may be imperfectly enforced due to Type I (false rejection) and Type II (false award) classification errors, whilst, in addition, the ex-post conditionality may be imperfectly enforced. If there are no classification errors - and thus no enforcement issues - it is always optimal to set C>0, whilst B=0 only if the benefit budget is sufficiently small. However, when classification errors occur, B=0 only if there are no Type I errors and the benefit budget is sufficiently small, while the conditions under which C>0 depend on the enforcement of the ex-post conditionality. We consider two discrete alternatives. Under No Enforcement C>0 only if the test administering C has some discriminatory power. In addition, social welfare is decreasing in the propensity to make each type error. However, under Full Enforcement C>0 for all levels of discriminatory power. Furthermore, whilst social welfare is decreasing in the propensity to make Type I errors, there are certain conditions under which it is increasing in the propensity to make Type II errors. This implies that there may be conditions under which it would be welfare enhancing to lower the chosen eligibility threshold - support the suggestion by Goodin (1985) to "err on the side of kindness".