Value stream analysis and mapping for product development

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2001."June 2001."Includes bibliographical references (p. 104-107).This thesis explores of Value Stream Analysis and Mapping (VSA/M) as applied to Product Development (PD) efforts. It contains three parts: the background and history of PD VSA/M, a report of the current PD VSA/M practices within the U.S. aerospace industry, and the proposal of a general VSA/M method for Product Development activities. Value Stream Analysis and Mapping is a method used for business process and product improvement, which originated with the development of the Lean business philosophy. The VSA/M background section includes a brief history of the method as described in foundational Lean literature. As with Lean practices in general, the application of VSA/M began in the manufacturing community, and has seen excellent results. However, the engineering and design efforts of Product Development provide a unique setting for the use of VSA/M. The report of current PD VSA/M practices within the U.S. aerospace industry focuses on the research results taken from site visits to nine major Product Development sites. The VSA/M tools used at the sites are characterized and ranked in sophistication. The business context surrounding the use of the tools is also characterized and ranked. The reduction of the research data and this analysis shows the importance of both tool sophistication and the surrounding context in the success of a PD VSA/M exercise. The proposal of a general VSA/M method for Product Development activities includes an outline for implementation. This outline is supported with a discussion of associated principles and the application of selected tools. The proposed method follows a pattern of analyzing and mapping the Current State of a process, and using heuristics to analyze and map an improved Future State. The tools used to accomplish this analysis and mapping include (1) a high-level Gantt chart or Ward/LEI map, (2) a detailed-level Process Flow map, and (3) a detailed-level Design Structure Matrix.by Richard L. Millard.S.M

Radio Emission from SN 1994I in NGC 5194 (M 51) - The Best Studied Type Ib/c Radio Supernova

We present the results of detailed monitoring of the radio emission from the Type Ic supernova SN 1994I from 3 days after optical discovery on 1994 March 31 until eight years later at age 2927 days on 2002 April 05. The data were mainly obtained using the Very Large Array at the five wavelengths, 1.3, 2.0, 3.6, 6.2, and 21 cm, and from the Cambridge 5 km Ryle Telescope at 2.0 cm. Two additional measurements were obtained at millimeter wavelengths. This data set represents the most complete, multifrequency radio observations ever obtained for a Type Ib/c supernova. The radio emission evolves regularly in both time and frequency and is well described by established SN emission/absorption models. It is the first radio supernova with sufficient data to show that it is clearly dominated by the effects of synchrotron self-absorption at early times.Comment: 43 pages, 5 figure

Antimicrobial resistance in dairy slurry tanks: A critical point for measurement and control

publishedVersionpublishedVersio

A comparative analysis of phenylpropanoid metabolism, N utilization, and carbon partitioning in fast- and slow-growing Populus hybrid clones

The biosynthetic costs of phenylpropanoid-derived condensed tannins (CTs) and phenolic glycosides (PGs) are substantial. However, despite reports of negative correlations between leaf phenolic content and growth of Populus, it remains unclear whether or how foliar biosynthesis of CT/PG interferes with tree growth. A comparison was made of carbon partitioning and N content in developmentally staged leaves, stems, and roots of two closely related Populus hybrid genotypes. The genotypes were selected as two of the most phytochemically divergent from a series of seven previously analysed clones that exhibit a range of height growth rates and foliar amino acid, CT, and PG concentrations. The objective was to analyse the relationship between leaf phenolic content and plant growth, using whole-plant carbon partitioning and N distribution data from the two divergent clones. Total N as a percentage of tissue dry mass was comparatively low, and CT and PG accrual comparatively high in leaves of the slow-growing clone. Phenylpropanoid accrual and N content were comparatively high in stems of the slow-growing clone. Carbon partitioning within phenylpropanoid and carbohydrate networks in developing stems differed sharply between clones. The results did not support the idea that foliar production of phenylpropanoid defence chemicals was the primary cause of reduced plant growth in the slow-growing clone. The findings are discussed in the context of metabolic mechanism(s) which may contribute to reduced N delivery from roots to leaves, thereby compromising tree growth and promoting leaf phenolic accrual in the slow-growing clone

ORIGINAL ARTICLES Assessment of Jeopardized Myocardium in Patients with One-vessel Disease

SUMMARY The size of the perfusion defect was assessed from a quantitative analysis of exercise thallium-201 images. Quantitative analysis was determined by measuring the area and the perimeter of the perfusion defect and expressing it as a percentage of the total left ventricular area or perimeter in three projections. Using this technique, we studied 50 patients with one-vessel disease of 50% or greater diameter narrowing. The planimetric and the perimetric methods correlated well (p < 0.001, r = 0.97). Of the 11 patients with less than 70% diameter narrowing, only one patient had abnormal exercise thallium-201 images. Of the remaining 39 patients with 70% or greater diameter narrowing, 35 circumflex disease. Mortality rates undoubtedly depend on left ventricular function: The worse the function, the poorer the prognosis. Therefore, the extent of jeopardized myocardium may have prognostic importance in patients with one-vessel disease; patients with more jeopardized myocardium may be at a higher risk of developing severe left ventricular dysfunction in the event of myocardium infarction. The purpose of this study was to assess the extent of jeopardized myocardium in patients with one-vessel disease by using quantitative analysis of exercise images, a simple technique that does not require computer manipulation, and to define the factors that affect the size of the defects in these patients. Materials and Methods We reviewed our records of exercise thallium-201 imaging and identified 50 patients with one-vessel disease who had undergone exercise perfusion imaging within 3 months of coronary angiography. There were 46 men and four women, ages 32-63 years (mean 52 years). Patients with associated cardiac diseases such as valvular heart disease or idiopathic hypertrophic subaortic stenosis and patients who had had previous bypass surgery were excluded. All patients were evaluated for symptoms of angina pectoris. No patient had unstable angina or historic or electrocardiographic evidence of myocardial infarction. Left-and right-heart catheterization, left ventriculography and coronary arteriography were per- formed with standard techniques. Each coronary vessel was visualized in multiple projections, including the sagittal oblique projection. Each patient had at least 50% diameter narrowing of one coronary artery. The lesion in the left anterior descending artery was classified as either proximal or distal to the first septal perforator and diagonal branches. In each patient with left circumflex artery disease, the lesion was before or involved the major posterolateral branch. In each patient with right coronary artery disease, the lesion was before the crux. The coronary circulation was rightdominant in patients with left circumflex or right coronary artery disease. The remaining vessels were either free of disease or had only slight luminal irregularities. Collaterals were considered present and significant if the collateral flow partially or completely opacified the diseased vessel beyond the site of occlusion or narrowing. The left ventriculograms, which were assessed qualitatively for wall-motion abnormalities, showed that none of these patients had akinetic or dyskinetic segments. The angiograms were reviewed by two experienced angiographers, and the consensus of both reviewers was used in the final interpretation. Exercise treadmill testing was performed according to the Bruce protocol. The end points of exercise were 2 2 mm of horizontal or downsloping ST depression (with or without angina), excessive fatigue or leg weakness, hypotension, frequent ventricular premature complexes, or attainment of at least 85% of the predicted maximal heart rate. Three electrocardiographic leads (V1, V, and aVF) were continuously monitored; lead V5 was used for interpretation. Blood pressure was obtained by the cuff method every 2 minutes. At peak exercise, 2 mCi of thallium-201 were injected intravenously and flushed with dextrose and water. The patient continued to exercise for 1 more minute. Within 10 minutes after injection, images were obtained in the anterior, left anterior oblique and left lateral projections by means of a commercially available scintillation camera (Baird Atomic System-77) equipped with a high-resolution, parallel-hole, 11/2-inch-thick collimator. Redistribution images were obtained 4 hours after exercise in the projections that showed the perfusion abnormalities. All patients in the study with initial abnormal images showed partia'L or complete redistribution in the delayed images. Our method for obtaining the exercise thallium-201 scintigrams has been described." 6 8 21-24 In brief, images were accumulated for a preset count (750,000 to 1,250,000 total counts), which required 8-12 minutes per projection. All images were corrected for background and for detector nonuniformity. Images were displayed on a television screen on a scale of 16 gray shades or 16 colors. The highest count displayed represents 100% on the scale and all other counts are digitally normalized to the maximum. Each of the 16 shades or colors represents a 6.25% increment in counts within the image. Depending on the visual in--spection of the background contribution, 20-30% background subtraction is used and the 16 colors are displayed over the remaining count range. In addition, the images were processed using an algorithm that weighs and spatially averages five adjacent data points in the matrix. The net result is a color-coded isocount contour display of the myocardial thallium-201 distribution. Polaroid pictures were obtained of the computer-smoothed images. We and others7' 25 have found that the color-coded display of the images improve the interpretation. Segments of the myocardium showing 25% decrease in counts (four-color shift) are considered abnormal. The borders of the defects are outlined by two independent observers and minor disagreements were settled by arbitration between the two observers. Quantitative analysis was done by two methods. In the first method, the size of the thallium-201 defect was determined by the method of Niess et al.26 with a computerized planimetry system (Hewlett-Packard 982A calculator and digitizer). This method expresses the size of thallium-201 perfusion defects as a percentage of total potential thallium uptake. The size of the defect was computed in each projection and expressed as a percentage of the total area of the myocardium, excluding the left ventricular cavity and the region of the valves. The average of the three projections was also determined ( In the second method, the perimeter of the defect was measured and expressed as a percentage of the total left ventricular perimeter in each projection ( Statistical analysis was performed using the t test or the analysis of variance when appropriate

Tikhonov adaptively regularized gamma variate fitting to assess plasma clearance of inert renal markers

The Tk-GV model fits Gamma Variates (GV) to data by Tikhonov regularization (Tk) with shrinkage constant, λ, chosen to minimize the relative error in plasma clearance, CL (ml/min). Using 169Yb-DTPA and 99mTc-DTPA (n = 46, 8–9 samples, 5–240 min) bolus-dilution curves, results were obtained for fit methods: (1) Ordinary Least Squares (OLS) one and two exponential term (E1 and E2), (2) OLS-GV and (3) Tk-GV. Four tests examined the fit results for: (1) physicality of ranges of model parameters, (2) effects on parameter values when different data subsets are fit, (3) characterization of residuals, and (4) extrapolative error and agreement with published correction factors. Test 1 showed physical Tk-GV results, where OLS-GV fits sometimes-produced nonphysical CL. Test 2 showed the Tk-GV model produced good results with 4 or more samples drawn between 10 and 240 min. Test 3 showed that E1 and E2 failed goodness-of-fit testing whereas GV fits for t > 20 min were acceptably good. Test 4 showed CLTk-GV clearance values agreed with published CL corrections with the general result that CLE1 > CLE2 > CLTk-GV and finally that CLTk-GV were considerably more robust, precise and accurate than CLE2, and should replace the use of CLE2 for these renal markers

Isolation, structure, and activity of GID, a novel alpha 4/7-conotoxin with an extended N-terminal sequence

Using assay-directed fractionation of Conus geographus crude venom, we isolated a-conotoxin GID, which acts selectively at neuronal nicotinic acetylcholine receptors (nAChRs). Unlike other neuronally selective alpha-conotoxins, alpha-GID has a four amino acid N-terminal tail, gamma-carboxyglutamate (Gla), and hydroxyproline (0) residues, and lacks an amidated C terminus. GID inhibits alpha7 and alpha3beta2 nAChRs with IC50 values of 5 and 3 nm, respectively and is at least 1000-fold less potent at the alpha1beta1gammadelta, alpha3beta4, and alpha4beta4 combinations. GID also potently inhibits the alpha4beta2 subtype (IC50 of 150 nm). Deletion of the N-terminal sequence (GIDDelta1-4) significantly decreased activity at the alpha4beta2 nAChR but hardly affected potency at alpha3beta2 and alpha7 nAChRs, despite enhancing the off-rates at these receptors. In contrast, Arg(12) contributed to alpha4beta2 and alpha7 activity but not to alpha3beta2 activity. The three-dimensional structure of GID is well defined over residues 4-19 with a similar motif to other a-conotoxins. However, despite its influence on activity, the tail appears to be disordered in solution. Comparison of GID with other alpha4/7-conotoxins which possess an NN(P/O) motif in loop II, revealed a correlation between increasing length of the aliphatic side-chain in position 10 (equivalent to 13 in GID) and greater alpha7 versus alpha3beta2 selectivity

Energy limitation of cyanophage development : implications for marine carbon cycling

RJP was in receipt of a Natural Environment Research Council (NERC) PhD studentship and a Warwick University IAS Fellowship. This work was also supported in part by NERC grant NE/N003241/1 and Leverhulme Trust grant RPG-2014-354 to A.D.M., D.J.E., and D.J.S.Marine cyanobacteria are responsible for ~25% of the fixed carbon that enters the ocean biosphere. It is thought that abundant co-occurring viruses play an important role in regulating population dynamics of cyanobacteria and thus the cycling of carbon in the oceans. Despite this, little is known about how viral infections ‘play-out’ in the environment, particularly whether infections are resource or energy limited. Photoautotrophic organisms represent an ideal model to test this since available energy is modulated by the incoming light intensity through photophosphorylation. Therefore, we exploited phototrophy of the environmentally relevant marine cyanobacterium Synechococcus and monitored growth of a cyanobacterial virus (cyanophage). We found that light intensity has a marked effect on cyanophage infection dynamics, but that this is not manifest by a change in DNA synthesis. Instead, cyanophage development appears energy limited for the synthesis of proteins required during late infection. We posit that acquisition of auxiliary metabolic genes (AMGs) involved in light-dependent photosynthetic reactions acts to overcome this limitation. We show that cyanophages actively modulate expression of these AMGs in response to light intensity and provide evidence that such regulation may be facilitated by a novel mechanism involving light-dependent splicing of a group I intron in a photosynthetic AMG. Altogether, our data offers a mechanistic link between diurnal changes in irradiance and observed community level responses in metabolism, i.e., through an irradiance-dependent, viral-induced release of dissolved organic matter (DOM).Publisher PDFPeer reviewe

Search for beautiful tetraquarks in the <i>ϒ</i>(1<i>S</i>)μ⁺μ⁻ invariant-mass spectrum

International audienceThe ϒ(1S)μ$^{+}$μ$^{−}$ invariant-mass distribution is investigated for a possible exotic meson state composed of two b quarks and two $\overline{b}$ quarks, ${X}_{b\overline{b}b\overline{b}}$ . The analysis is based on a data sample of pp collisions recorded with the LHCb detector at centre-of-mass energies $\sqrt{s}=7$ , 8 and 13 TeV, corresponding to an integrated luminosity of 6.3 fb$^{−1}$. No significant excess is found, and upper limits are set on the product of the production cross-section and the branching fraction as functions of the mass of the ${X}_{b\overline{b}b\overline{b}}$ state. The limits are set in the fiducial volume where all muons have pseudorapidity in the range [2.0, 5.0], and the ${X}_{b\overline{b}b\overline{b}}$ state has rapidity in the range [2.0, 4.5] and transverse momentum less than 15 GeV/c