77 research outputs found
AGILE–STAGE GATE MANAGEMENT (ASGM): NPD IMPLEMENTATION PRACTICES FROM GLOBAL FIRMS DEVELOPING COMPLEX, PHYSICAL PRODUCTS
Stage Gate Management (SGM) has been used successfully by global organizations to direct the New Product Development process (NPD) for years, recently a new variant of this venerable approach has emerged. Researchers and firms have begun to intersperse elements of Agile, as popularized for the development of software, to create an Agile – Stage Gate Management (ASGM) hybrid NPD framework. Agile practitioners believe in process waste reduction, an intense focus on customers, and the creation of nimble entrepreneurial project teams, which, for software products, has positively impacted development time to market, resource utilization, and market success, more generally, improved business outcomes. For NPD professionals responsible for physical products, not solely software, do these Agile tenets continue to produce results? With minimal available research, a Grounded Theory study was conducted to inductively create theory from the implementation of ASGM, specifically for firms that design, develop, and manufacture physical products. Twenty-nine experienced industry professionals were interviewed from four global companies which represented five distinct Business Units (BU) which competed in a variety of markets and industries around the world. From these interviews, a Content Analysis approach was employed to organize primary and secondary themes which illustrated NPD team practices. Additionally, a comparative multi-case study method further developed specific Agile/Scrum techniques implemented, the measures of business success realized, as well as, a new ASGM model for like firms. From this research, firms which developed physical products did not implement all Agile practices, only Team Interface, Product Demonstrations, and Specification Flexibility were uncovered. The cases did, however, subjectively realize an improved time to market, as well as, greater product success for projects commercialized using ASGM. Lastly, a new framework emerged which highlighted the unique practice of Agile behaviors earlier in the development process, but rigid, or SGM-like, activities closer towards product launch
Agile Stage-Gate Management (ASGM) for physical products
We present a qualitative study of Agile Stage-Gate Management (ASGM),: a hybrid new product development methodology that combines Agile and Stage-Gate Management (SGM) approaches for the coordination of new product development. When applied to software projects, Agile is expected to deliver reduced development times, improved resource utilization, and greater financial success. We examine whether ASGM practitioners realize similar outcomes in a sample of global firms developing complex electro-mechanical products (e.g., automobile components, railway propulsion systems, and medical devices). Our grounded theory approach articulates an understanding of ASGM through extensive interviews of experienced professionals. Our thematic analysis supports many expected benefits (i.e., speed to market, innovation enabling), but also does not encourage others, and reveals new pitfalls that deserve recognition (i.e., resource inefficiency). ASGM is not a panacea for all product development. Overall, physical product firms adopting this method can expect reduced development times and higher levels of innovation but will expend more resources to complete development projects, but a dichotomy exists. Physical product developers using ASGM experience a negative impact on project resource efficiency due to the need for dedicated resources, frequent product demonstrations, and duplicative management structures
Observational limits on type 1 active galactic nucleus rate in COSMOS
We present black hole masses and accretion rates for 182 Type 1 active galactic nuclei (AGNs) in COSMOS.
We estimate masses using the scaling relations for the broad H β, Mg ii, and C iv emission lines in the
redshift ranges 0.16 < z < 0.88, 1 < z < 2.4, and 2.7 < z < 4.9. We estimate the accretion rate using an
Eddington ratio LI/L_(Edd) estimated from optical and X-ray data.We find that very few Type 1 AGNs accrete below
LI/L_(Edd) ∼ 0.01, despite simulations of synthetic spectra which show that the survey is sensitive to such Type
1 AGNs. At lower accretion rates the broad-line region may become obscured, diluted, or nonexistent. We find
evidence that Type 1 AGNs at higher accretion rates have higher optical luminosities, as more of their emission
comes from the cool (optical) accretion disk with respect to shorter wavelengths. We measure a larger range
in accretion rate than previous works, suggesting that COSMOS is more efficient at finding low accretion rate
Type 1 AGNs. However, the measured range in accretion rate is still comparable to the intrinsic scatter from the
scaling relations, suggesting that Type 1 AGNs accrete at a narrow range of Eddington ratio, with LI/L_(Edd) ∼ 0.1
Observational Limits on Type 1 AGN Accretion Rate in COSMOS
We present black hole masses and accretion rates for 182 Type 1 AGN in
COSMOS. We estimate masses using the scaling relations for the broad Hb, MgII,
and CIV emission lines in the redshift ranges 0.16<z<0.88, 1<z<2.4, and
2.7<z<4.9. We estimate the accretion rate using an Eddington ratio L_I/L_Edd
estimated from optical and X-ray data. We find that very few Type 1 AGN accrete
below L_I/L_Edd ~ 0.01, despite simulations of synthetic spectra which show
that the survey is sensitive to such Type 1 AGN. At lower accretion rates the
BLR may become obscured, diluted or nonexistent. We find evidence that Type 1
AGN at higher accretion rates have higher optical luminosities, as more of
their emission comes from the cool (optical) accretion disk with respect to
shorter wavelengths. We measure a larger range in accretion rate than previous
works, suggesting that COSMOS is more efficient at finding low accretion rate
Type 1 AGN. However the measured range in accretion rate is still comparable to
the intrinsic scatter from the scaling relations, suggesting that Type 1 AGN
accrete at a narrow range of Eddington ratio, with L_I/L_Edd ~ 0.1.Comment: Accepted for pulication in ApJ. 7 pages, 5 figures, table 1 available
on reques
Star Formation at From the Spitzer Large Area Survey with Hyper-Suprime-Cam (SPLASH)
Using the first 50% of data collected for the Spitzer Large Area Survey with
Hyper-Suprime-Cam (SPLASH) observations on the 1.8 deg Cosmological
Evolution Survey (COSMOS) we estimate the masses and star formation rates of
3398 star-forming galaxies at with a
substantial population up to . We find that the
strong correlation between stellar mass and star formation rate seen at lower
redshift (the "main sequence" of star-forming galaxies) extends to .
The observed relation and scatter is consistent with a continued increase in
star formation rate at fixed mass in line with extrapolations from
lower-redshift observations. It is difficult to explain this continued
correlation, especially for the most massive systems, unless the most massive
galaxies are forming stars near their Eddington-limited rate from their first
collapse. Furthermore, we find no evidence for moderate quenching at higher
masses, indicating quenching either has not occurred prior to or
else occurs rapidly, so that few galaxies are visible in transition between
star-forming and quenched.Comment: ApJL, accepte
The Nature of Optically Dull Active Galactic Nuclei in COSMOS
We present infrared, optical, and X-ray data of 48 X-ray bright, optically
dull AGNs in the COSMOS field. These objects exhibit the X-ray luminosity of an
active galactic nucleus (AGN) but lack broad and narrow emission lines in their
optical spectrum. We show that despite the lack of optical emission lines, most
of these optically dull AGNs are not well-described by a typical passive red
galaxy spectrum: instead they exhibit weak but significant blue emission like
an unobscured AGN. Photometric observations over several years additionally
show significant variability in the blue emission of four optically dull AGNs.
The nature of the blue and infrared emission suggest that the optically
inactive appearance of these AGNs cannot be caused by obscuration intrinsic to
the AGNs. Instead, up to ~70% of optically dull AGNs are diluted by their
hosts, with bright or simply edge-on hosts lying preferentially within the
spectroscopic aperture. The remaining ~30% of optically dull AGNs have
anomalously high f_x/f_o ratios and are intrinsically weak, not obscured, in
the optical. These optically dull AGNs are best described as a weakly accreting
AGN with a truncated accretion disk from a radiatively inefficient accretion
flow.Comment: 12 pages, 10 figures. Accepted for publication in the Ap
The COSMOS AGN Spectroscopic Survey I: XMM Counterparts
We present optical spectroscopy for an X-ray and optical flux-limited sample
of 677 XMM-Newton selected targets covering the 2 deg^2 COSMOS field, with a
yield of 485 high-confidence redshifts. The majority of the spectra were
obtained over three seasons (2005-2007) with the IMACS instrument on the
Magellan (Baade) telescope. We also include in the sample previously published
Sloan Digital Sky Survey spectra and supplemental observations with
MMT/Hectospec. We detail the observations and classification analyses. The
survey is 90% complete to flux limits of f_{0.5-10 keV}>8 x 10^-16 erg cm^-2
s^-1 and i_AB+<22, where over 90% of targets have high-confidence redshifts.
Making simple corrections for incompleteness due to redshift and spectral type
allows for a description of the complete population to $i_AB+<23. The corrected
sample includes 57% broad emission line (Type 1, unobscured) AGN at
0.13<z<4.26, 25% narrow emission line (Type 2, obscured) AGN at 0.07<z<1.29,
and 18% absorption line (host-dominated, obscured) AGN at 0<z<1.22 (excluding
the stars that made up 4% of the X-ray targets). We show that the survey's
limits in X-ray and optical flux include nearly all X-ray AGN (defined by
L_{0.5-10 keV}>3 x 10^42 erg s^-1) to z<1, of both optically obscured and
unobscured types. We find statistically significant evidence that the obscured
to unobscured AGN ratio at z<1 increases with redshift and decreases with
luminosity.Comment: Accepted for publication in the ApJ. 31 pages, 17 figures. Table 2 is
available on reques
Eight-Dimensional Mid-Infrared/Optical Bayesian Quasar Selection
We explore the multidimensional, multiwavelength selection of quasars from
mid-IR (MIR) plus optical data, specifically from Spitzer-IRAC and the Sloan
Digital Sky Survey (SDSS). We apply modern statistical techniques to combined
Spitzer MIR and SDSS optical data, allowing up to 8-D color selection of
quasars. Using a Bayesian selection method, we catalog 5546 quasar candidates
to an 8.0 um depth of 56 uJy over an area of ~24 sq. deg; ~70% of these
candidates are not identified by applying the same Bayesian algorithm to
4-color SDSS optical data alone. Our selection recovers 97.7% of known type 1
quasars in this area and greatly improves the effectiveness of identifying
3.5<z<5 quasars. Even using only the two shortest wavelength IRAC bandpasses,
it is possible to use our Bayesian techniques to select quasars with 97%
completeness and as little as 10% contamination. This sample has a photometric
redshift accuracy of 93.6% (Delta Z +/-0.3), remaining roughly constant when
the two reddest MIR bands are excluded. While our methods are designed to find
type 1 (unobscured) quasars, as many as 1200 of the objects are type 2
(obscured) quasar candidates. Coupling deep optical imaging data with deep
mid-IR data could enable selection of quasars in significant numbers past the
peak of the quasar luminosity function (QLF) to at least z~4. Such a sample
would constrain the shape of the QLF and enable quasar clustering studies over
the largest range of redshift and luminosity to date, yielding significant
gains in our understanding of quasars and the evolution of galaxies.Comment: 49 pages, 14 figures, 7 tables. AJ, accepte
The zCOSMOS 10k-Bright Spectroscopic Sample
We present spectroscopic redshifts of a large sample of galaxies with I_(AB) < 22.5 in the COSMOS field, measured from spectra of 10,644 objects that have been obtained in the first two years of observations in the zCOSMOS-bright redshift survey. These include a statistically complete subset of 10,109 objects. The average accuracy of individual redshifts is 110 km s^(–1), independent of redshift. The reliability of individual redshifts is described by a Confidence Class that has been empirically calibrated through repeat spectroscopic observations of over 600 galaxies. There is very good agreement between spectroscopic and photometric redshifts for the most secure Confidence Classes. For the less secure Confidence Classes, there is a good correspondence between the fraction of objects with a consistent photometric redshift and the spectroscopic repeatability, suggesting that the photometric redshifts can be used to indicate which of the less secure spectroscopic redshifts are likely right and which are probably wrong, and to give an indication of the nature of objects for which we failed to determine a redshift. Using this approach, we can construct a spectroscopic sample that is 99% reliable and which is 88% complete in the sample as a whole, and 95% complete in the redshift range 0.5 < z < 0.8. The luminosity and mass completeness levels of the zCOSMOS-bright sample of galaxies is also discussed
Machupo Virus Glycoprotein Determinants for Human Transferrin Receptor 1 Binding and Cell Entry
Machupo virus (MACV) is a highly pathogenic New World arenavirus that causes hemorrhagic fever in humans. MACV, as well as other pathogenic New World arenaviruses, enter cells after their GP1 attachment glycoprotein binds to their cellular receptor, transferrin receptor 1 (TfR1). TfR1 residues essential for this interaction have been described, and a co-crystal of MACV GP1 bound to TfR1 suggests GP1 residues important for this association. We created MACV GP1 variants and tested their effect on TfR1 binding and virus entry to evaluate the functional significance of some of these and additional residues in human and simian cells. We found residues R111, D123, Y122, and F226 to be essential, D155, and P160 important, and D114, S116, D140, and K169 expendable for the GP1-TfR1 interaction and MACV entry. Several MACV GP1 residues that are critical for the interaction with TfR1 are conserved among other New World arenaviruses, indicating a common basis of receptor interaction. Our findings also open avenues for the rational development of viral entry inhibitors
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