654 research outputs found
Lean Startup as an Entrepreneurial Strategy: Limitations, Outcomes and Learnings for Practitioners
Purpose: This paper aims to address threecore questions around (1) what limitations exit with the methodology and/or its use; (2) what is the methodology's impact
on performance outcomes; and (3) what learnings can practitioners and educators employ as part of the startup efforts.
Methodology: A review of available peer and non-peer review literature relevant to the lean startup methodology, its limitations (pitfalls, fallacies, problems), and
outcomes to address the core questions.
Findings: This review identifies limitations with the methodology in several areas: business sector fit; issues associated with customer discovery; experimentation;
iterating/pivoting; and the minimum viable product. Limitations may be related to the methodology, the incomplete understanding of its fundamental components,
inconsistent (and non-rigorous) use of the methodology, and the inability to address risks (e.g., technological) beyond resolving market uncertainty. Also, experience
related to outcomes with the lean startup reveals mixed findings due to the diverse methods, populations, and endpoints used. Such facets underly the mix of
experiences seen in both the peer and non-peer review literature. This review identifies that rigorous implementation leads to statistically significant (P<0.05) outcome
differences (e.g., discarding poor ideas, number of pivots, and revenue realization).
Practical Implications: Practitioners and educators should consider educational, implementation, business sector, outside influences, outcomes, and investor
preferences to use the methodology.
Originality: This paper provides one of the first extensive literature reviews to examine what limits exist, where, and whether these are associated with the
methodology or due to user, cultural, or business sector considerations. It also provides several relevant learnings for practitioners and educators to consider when
using the methodology.
Conclusions: Current evidence indicates that multiple issues do exist. Such limits are related to the methodology's inherent structure and user, sector, and external
influence considerations. Further, outcomes vary based on study methods, variables, populations, business verticals, and implementation. Practitioners should
consider some of the recommendations offered when utilizing this methodology to optimize their experience and outcomes
Customer Development, Innovation, and Decision-Making Biases int he Lean Startup
This paper reviews current research relevant to new product development, customer development, and the lean startup. Customer development and the lean startup are a new and increasingly used form of entrepreneurship process, which rely on hypothesis testing but not in the traditional sense; the entrepreneur is encouraged to scan the environment, collect information, and form and evaluate educated guesses so as to make accurate judgments and decisions. The present research provides a review of the customer development model for entrepreneurial activities and a critique of this hypothesis testing methodology. We then consider ways in which to improve decision making within the startup via a systematic study of System 1 ( intuition) and System 2 ( reasoned and rational) decision-making styles. This paper has significant implications for entrepreneurs, entrepreneurship support organizations, such as incubators and accelerators, and entrepreneurship educators, all of whom are increasingly practicing and teaching this process
Seeing What Others Miss: A Study of Women Entrepreneurs in High-Growth Startups
A pressing question in entrepreneurial research is where opportunities come from. Prior research indicates that some opportunities stem from known parameters and outcomes; some are discovered through engagement with unknown but knowable factors; and others are unknowable until brought into being through a creative process. This paper explores the second and more prevailing view in entrepreneurial research – that individuals discover business opportunity – and examines how high-growth entrepreneurs perceive opportunity through engagement with the world. Survey results, based on responses from 165 women entrepreneurs in high-growth startups, indicate that individuals with a strong discover mindset act and think in ways that support opportunity perception. Coupled with a belief in her abilities, the entrepreneur is more likely to move from opportunity perception to new venture creation. Results from semi-structured interviews with women from the same population elucidate the survey findings and yield implications for entrepreneurial theory and practice
Providing a Piece of the Puzzle: Insights into the Aircraft Availability Conundrum
Aircraft availability (AA) is a key metric for assessing operational readiness. The declining trend in AA is a documented concern for senior Air Force leaders. This paper aims to investigate the components of non-available time and subsequently focuses on the largest and fastest growing category: not mission capable maintenance unscheduled (NMCMU). Then, utilization of aircraft platforms is examined to determine the readiness benefits of increasing available hours
Distinguishing entrepreneurial approaches to opportunity perception
Purpose – Whether opportunities are discovered or created by entrepreneurs is a foundational question in entrepreneurship research. The purpose of this paper is to examine women entrepreneurs in high-growth new ventures and explore the cognitive resources that distinguish between three approaches to opportunity perception: opportunity discovery; opportunity creation; and a combined discover-create (ambidextrous) approach.
Design/methodology/approach – Using questionnaire responses from 165 women entrepreneurs in highgrowth new ventures, K-means clustering was used to determine three approaches to opportunity perception. The cognitive resources associated with each approach were then identified using multiple discriminant analysis. Finally, multivariate analysis of variance was conducted to examine the relationship between opportunity perception and growth expectations.
Findings – These results demonstrate different approaches to opportunity perception among entrepreneurs in high-growth new ventures, the cognitive resources that reinforce each approach, and the expected new venture growth outcomes.
Research limitations/implications – The findings offer insight on the cognitive origins of opportunity perception by empirically identifying distinct approaches to opportunity perception and the cognitive resources that underlie each. The study relies on a unique sample of entrepreneurs to understand complex cognitive phenomenon.
Practical implications – Understanding the effects that cognitive factors have on opportunity perception provides direction for current and aspiring entrepreneurs. The findings and instrument may be used for professional development and to inform educational strategies.
Originality/value – The findings offer important contributions to entrepreneurial theory and practice by addressing repeated calls for research that examines the cognitive antecedents enabling opportunity formation (discovery, creation or both). This manuscript empirically does so, while opening up possibilities for future research
Immune response in a wild bird is predicted by oxidative status, but does not cause oxidative stress.
The immune system provides vital protection against pathogens, but extensive evidence suggests that mounting immune responses can entail survival and fecundity costs. The physiological mechanisms that underpin these costs remain poorly understood, despite their potentially important role in shaping life-histories. Recent studies involving laboratory models highlight the possibility that oxidative stress could mediate these costs, as immune-activation can increase the production of reactive oxygen species leading to oxidative stress. However, this hypothesis has rarely been tested in free-ranging wild populations, where natural oxidative statuses and compensatory strategies may moderate immune responses and their impacts on oxidative status. Furthermore, the possibility that individuals scale their immune responses according to their oxidative status, conceivably to mitigate such costs, remains virtually unexplored. Here, we experimentally investigate the effects of a phytohaemagglutinin (PHA) immune-challenge on oxidative status in wild male and female white-browed sparrow weavers, Plocepasser mahali. We also establish whether baseline oxidative status prior to challenge predicts the scale of the immune responses. Contrary to previous work on captive animals, our findings suggest that PHA-induced immune-activation does not elicit oxidative stress. Compared with controls (n = 25 birds), PHA-injected birds (n = 27 birds) showed no evidence of a differential change in markers of oxidative damage or enzymatic and non-enzymatic antioxidant protection 24 hours after challenge. We did, however, find that the activity of a key antioxidant enzyme (superoxide dismutase, SOD) prior to immune-activation predicted the scale of the resulting swelling: birds with stronger initial SOD activity subsequently produced smaller swellings. Our findings (i) suggest that wild birds can mount immune responses without suffering from systemic oxidative stress, and (ii) lend support to biomedical evidence that baseline oxidative status can impact the scale of immune responses; a possibility not yet recognised in ecological studies of immunity
Broad Absorption Line Variability in Repeat Quasar Observations from the Sloan Digital Sky Survey
We present a time-variability analysis of 29 broad absorption line quasars
(BALQSOs) observed in two epochs by the Sloan Digital Sky Survey (SDSS). These
spectra are selected from a larger sample of BALQSOs with multiple observations
by virtue of exhibiting a broad CIV 1549 absorption trough separated
from the rest frame of the associated emission peak by more than 3600 km
s. Detached troughs facilitate higher precision variability
measurements, since the measurement of the absorption in these objects is not
complicated by variation in the emission line flux. We have undertaken a
statistical analysis of these detached-trough BALQSO spectra to explore the
relationships between BAL features that are seen to vary and the dynamics of
emission from the quasar central engine. We have measured variability within
our sample, which includes three strongly variable BALs. We have also verified
that the statistical behavior of the overall sample agrees with current model
predictions and previous studies of BAL variability. Specifically, we observe
that the strongest BAL variability occurs among the smallest equivalent width
features and at velocities exceeding 12,000 km s, as predicted by recent
disk-wind modeling.Comment: 11 pages, 7 figures. Accepted for publication in Ap
Formation and Evolution of the Disk System of the Milky Way: [alpha/Fe] Ratios and Kinematics of the SEGUE G-Dwarf Sample
We employ measurements of the [alpha/Fe] ratio derived from low-resolution
(R~2000) spectra of 17,277 G-type dwarfs from the SEGUE survey to separate them
into likely thin- and thick-disk subsamples. Both subsamples exhibit strong
gradients of orbital rotational velocity with metallicity, of opposite signs,
-20 to -30 km/s/dex for the thin-disk and +40 to +50 km/s/dex for the
thick-disk population. The rotational velocity is uncorrelated with
Galactocentric distance for the thin-disk subsample, and exhibits a small trend
for the thick-disk subsample. The rotational velocity decreases with distance
from the plane for both disk components, with similar slopes (-9.0 {\pm} 1.0
km/s/kpc). Thick-disk stars exhibit a strong trend of orbital eccentricity with
metallicity (about -0.2/dex), while the eccentricity does not change with
metallicity for the thin-disk subsample. The eccentricity is almost independent
of Galactocentric radius for the thin-disk population, while a marginal
gradient of the eccentricity with radius exists for the thick-disk population.
Both subsamples possess similar positive gradients of eccentricity with
distance from the Galactic plane. The shapes of the eccentricity distributions
for the thin- and thick-disk populations are independent of distance from the
plane, and include no significant numbers of stars with eccentricity above 0.6.
Among several contemporary models of disk evolution we consider, radial
migration appears to have played an important role in the evolution of the
thin-disk population, but possibly less so for the thick disk, relative to the
gas-rich merger or disk heating scenarios. We emphasize that more physically
realistic models and simulations need to be constructed in order to carry out
the detailed quantitative comparisons that our new data enable.Comment: Accepted for publication in ApJ, 18 pages, 12 figures, 2 tables,
emulateapj forma
Optical and Radio Properties of Extragalactic Sources Observed by the FIRST and SDSS Surveys
We discuss the optical and radio properties of 30,000 FIRST sources
positionally associated with an SDSS source in 1230 deg of sky. The
majority (83%) of the FIRST sources identified with an SDSS source brighter
than r=21 are optically resolved. We estimate an upper limit of 5% for the
fraction of quasars with broad-band optical colors indistinguishable from those
of stars. The distribution of quasars in the radio flux -- optical flux plane
supports the existence of the "quasar radio-dichotomy"; 8% of all quasars with
i<18.5 are radio-loud and this fraction seems independent of redshift and
optical luminosity. The radio-loud quasars have a redder median color by 0.08
mag, and a 3 times larger fraction of objects with red colors. FIRST galaxies
represent 5% of all SDSS galaxies with r<17.5, and 1% for r<20, and are
dominated by red galaxies. Magnitude and redshift limited samples show that
radio galaxies have a different optical luminosity distribution than non-radio
galaxies selected by the same criteria; when galaxies are further separated by
their colors, this result remains valid for both blue and red galaxies. The
distributions of radio-to-optical flux ratio are similar for blue and red
galaxies in redshift-limited samples; this similarity implies that the
difference in their luminosity functions, and resulting selection effects, are
the dominant cause for the preponderance of red radio galaxies in flux-limited
samples. We confirm that the AGN-to-starburst galaxy number ratio increases
with radio flux, and find that radio emission from AGNs is more concentrated
than radio emission from starburst galaxies (abridged).Comment: submitted to AJ, color gif figures, PS figures available from
[email protected]
The Ensemble Photometric Variability of ~25000 Quasars in the Sloan Digital Sky Survey
Using a sample of over 25000 spectroscopically confirmed quasars from the
Sloan Digital Sky Survey, we show how quasar variability in the rest frame
optical/UV regime depends upon rest frame time lag, luminosity, rest
wavelength, redshift, the presence of radio and X-ray emission, and the
presence of broad absorption line systems. The time dependence of variability
(the structure function) is well-fit by a single power law on timescales from
days to years. There is an anti-correlation of variability amplitude with rest
wavelength, and quasars are systematically bluer when brighter at all
redshifts. There is a strong anti-correlation of variability with quasar
luminosity. There is also a significant positive correlation of variability
amplitude with redshift, indicating evolution of the quasar population or the
variability mechanism. We parameterize all of these relationships. Quasars with
RASS X-ray detections are significantly more variable (at optical/UV
wavelengths) than those without, and radio loud quasars are marginally more
variable than their radio weak counterparts. We find no significant difference
in the variability of quasars with and without broad absorption line troughs.
Models involving multiple discrete events or gravitational microlensing are
unlikely by themselves to account for the data. So-called accretion disk
instability models are promising, but more quantitative predictions are needed.Comment: 41 pages, 21 figures, AASTeX, Accepted for publication in Ap
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