18,072 research outputs found
Creating New Ventures: A review and research agenda
Creating new ventures is one of the most central topics to entrepreneurship and is a critical step from which many theories of management, organizational behavior, and strategic management build. Therefore, this review and proposed research agenda is not only relevant to entrepreneurship scholars but also other management scholars who wish to challenge some of the implicit assumptions of their current streams of research and extend the boundaries of their current theories to earlier in the organization’s life. Given that the last systematic review of the topic was published 16 years ago, and that the topic has evolved rapidly over this time, an overview and research outlook are long overdue. From our review, we inductively generated ten sub-topics: (1) Lead founder, (2) Founding team, (3) Social relationships, (4) Cognitions, (5) Emergent organizing, (6) New venture strategy, (7) Organizational emergence, (8) New venture legitimacy, (9) Founder exit, and (10) Entrepreneurial environment. These sub-topics are then organized into three major stages of the entrepreneurial process—co-creating, organizing, and performing. Together, the framework provides a cohesive story of the past and a road map for future research on creating new ventures, focusing on the links connecting these sub-topics
Coupled Cluster Channels in the Homogeneous Electron Gas
We discuss diagrammatic modifications to the coupled cluster doubles (CCD)
equations, wherein different groups of terms out of rings, ladders,
crossed-rings and mosaics can be removed to form approximations to the coupled
cluster method, of interest due to their similarity with various types of
random phase approximations. The finite uniform electron gas is benchmarked for
14- and 54-electron systems at the complete basis set limit over a wide density
range and performance of different flavours of CCD are determined. These
results confirm that rings generally overcorrelate and ladders generally
undercorrelate; mosaics-only CCD yields a result surprisingly close to CCD. We
use a recently developed numerical analysis [J. J. Shepherd and A. Gr\"uneis,
Phys. Rev. Lett. 110, 226401 (2013)] to study the behaviours of these methods
in the thermodynamic limit. We determine that the mosaics, on forming the
Brueckner Hamltonian, open a gap in the effective one-particle eigenvalues at
the Fermi energy. Numerical evidence is presented which shows that methods
based on this renormalisation have convergent energies in the thermodynamic
limit including mosaic-only CCD, which is just a renormalised MP2. All other
methods including only a single channel, namely ladder-only CCD, ring-only CCD
and crossed-ring-only CCD, appear to yield divergent energies; incorporation of
mosaic terms prevents this from happening.Comment: 9 pages, 4 figures, 1 table. Comments welcome: [email protected]
The Impact of Regional and Institutional Factors on Labour productive Performance : Evidence from the Township and Village Enterprise sector in China
This paper investigates the impact of regional and institutional factors on labor productivity in China’s Township and Village Enterprise (TVE) sector, one of the pillar industries of the economy. Employing a balanced provincial panel dataset, we find a significant variation in the factors determining regional labor productivity between the three macro-regions. The factors of capital
investment intensity, foreign intensity, and export intensity behave differently with a significant regional diversity. Only human capital, the real wage, and firm size are identified as the common determinants across regions. A strong self-reinforcing effect has been found with
a high degree of persistence in the behavior of, and hence slow or negligible convergence in labor productivity between regions. We find that the labor efficiency gains have been generated more from internal rather than external economies of scale across regions as well as the country as a whole. We also find that the government privatization reforms have had both a short run and increasingly long-term positive impact on the TVE labor productivity across the regions. This finding may indicate that institutional privatization can be an effective tool in promoting industrialization and labor productive performance in China as well as in other transitional economies
Resolved CO(1-0) Nuclei in IRAS 14348-1447: Evidence for Massive Bulge Progenitors to Ultraluminous Infrared Galaxies
High-resolution, CO(1-0) interferometry of the ultraluminous infrared galaxy
IRAS 14348-1447 is presented. The merger system has a molecular gas mass of
\~3x10^10 solar masses and a projected nuclear separation of 4.8 kpc (3.5"),
making it one of the most molecular gas-rich galaxies known and an ideal
candidate for studying the intermediate stages of an ultraluminous merger
event. The CO morphology shows two molecular gas components associated with the
stellar nuclei of the progenitors, consistent with the idea that the molecular
disks are gravitationally bound by the dense bulges of the progenitor galaxies
as the interaction proceeds. In contrast, less luminous infrared galaxies
observed to date with projected nuclear separations of ~<5 kpc show a dominant
CO component between the stellar nuclei. This discrepancy may be an indication
that the progenitors of mergers with lower infrared luminosity do not possess
massive bulges, and that the gas is stripped during the initial encounter of
their progenitors. A comparison of the CO and radio luminosities of the NE and
SW component show them to have comparable radio and CO flux ratios of
f(NE)/f(SW) ~0.6, possibly indicating that the amount of star-forming molecular
gas in the progenitors is correlated with the supernovae rate. The estimate of
molecular gas masses of the nuclei and the extent of the radio emission are
used to infer that the nuclei of IR 14348-1447 have gas densities comparable to
the cores of elliptical galaxies.Comment: LaTex, 5 pages with 1 postscript and 1 jpg figure, ApJ Letters, in
pres
FTIR-DRIFTS-based prediction of β-carotene, α-tocopherol and L-ascorbic acid in mango (Mangifera indica L.) fruit pulp
Mango fruits contain substantial vitamins and dietary fibre. Vitamins vary among and within fruits depending on cultivar type and ripening stage. Conventional techniques of vitamins analysis are based on High Pressure Liquid Chromatography, which are costly and laborious. This study evaluated the potential of Fourier transform infrared-diffuse reflectance spectroscopy (FTIR-DRIFTS) technique in predicting β-carotene, α-tocopherol and L-ascorbic acid in pulps of four mango cultivar types (‘Apple’, ‘Kent’, ‘Ngowe’, and ‘Tommy Atkins’). Combination of ran dom forest (RF) and first derivative spectra developed the predictive models. Factorial ANOVA examined the interaction effect of cultivar type, site (‘Thika’, ‘Embu’ and ‘Machakos), and fruit canopy position (sun exposed/within crown) on β-carotene, α-tocopherol and L-ascorbic acid contents. RF Models gave R2 = 0.97, RMSE = 2.27, RPD = 0.72 for β-carotene; R2 = 0.98, RMSE = 0.26, RPD = 0.30 for α-tocopherol and R2 = 0.96, RMSE = 0.51, RPD = 1.96 for L-ascorbic acid. Generally cultivar type affected vitamin C, F (3, 282) = 7.812, p < 0.05. Apple and Tommy Atkins had higher mean vitamins than Ngowe and Kent. In Machakos, within canopy fruits had higher β-carotene than sun-exposed fruits, F (5, 257) = 2.328, p = 0.043. However, interactions between fruit position, site and cultivar did not affect α-tocopherol and vitamin C. In Thika, Tommy Atkins at fully ripe stage had higher vitamin C than at intermediate maturity stage, F (2, 143) = 7.328, p = 0.01. These results show that FTIR-DRIFTS spectroscopy is a high-throughput method that can be used to predict mango fruit vitamins of in a large data set
The two sided parsec scale structure of the Low Luminosity Active Galactic Nucleus in NGC 4278
We present new Very Long Baseline Interferometry observations of the LINER
galaxy NGC 4278. The observations were taken with the Very Long Baseline Array
(VLBA) and a single antenna of the Very Large Array (VLA) at 5 GHz and 8.4 GHz
and have a linear resolution of <0.1 pc. Our radio data reveal a two sided
structure, with symmetric S-shaped jets emerging from a flat spectrum core. We
fit the jet brightness with gaussian components, which we identify from a
previous observation taken five years before. By comparing the positions of the
components in the two epochs, we measure motions between 0.45 +/- 0.14 and 3.76
+/- 0.65 mas, corresponding to apparent velocities < 0.2c, and to ages in the
range 8.3 - 65.8 years. Assuming that the radio morphology is intrinsically
symmetric and its appearance is governed by Doppler beaming effects, we find
that NGC4278 has mildly relativistic jets (beta ~ 0.75), closely aligned to the
line-of-sight (2 degrees < theta < 4 degrees). Alternatively, the source could
be oriented at a larger angle and asymmetries could be related to the jet
interaction with the surrounding medium. We also present new simultaneous VLA
observations between 1.4 and 43 GHz, and a 5 GHz light curve between 1972 and
2003. The radio spectrum can be fit by a relatively steep power-law (alpha =
0.54). We find significant variability at 5 GHz. All these arguments indicate
that the radiation from NGC 4278 is emitted via the synchrotron process by
relativistic particles accelerated by a supermassive black hole. Despite a much
lower power, this is the same process that takes place in ordinary radio loud
AGNs.Comment: 29 pages, 9 figures, ApJ accepte
A simple field based method for rapid wood density estimation for selected tree species in Western Kenya
Wood density is an important variable for accurate quantification of woody biomass and carbon stocks. Conventional destructive methods for wood density estimation are resource intensive, prohibiting their use, limiting the application of approaches that would minimize uncertainties in tree biomass estimates. We tested an alternative method involving tree coring with a carpenter's auger to estimate wood density of seven tropical tree species in Western Kenya. We used conventional water immersion method to validate results from the auger core method. The mean densities (and 95% confidence intervals) ranged from 0.36 g cm−3 (0.25–0.47) to 0.67 g cm−3 (0.61–0.73) for the auger core method, and 0.46 g cm−3 (0.42–0.50) to 0.67 g cm−3 (0.61–0.73) for the water immersion method. The auger core and water immersion methods were not significantly different for four out of seven tree species namely; Acacia mearnsii, Mangifera indica, Eucalyptus grandis and Grevillea robusta. However, wood densities estimated from the auger core method were lower (t (61) = 7.992, P = <0.001). The ease of the auger core method application, as a non-destructive method in acquiring wood density data, is a worthy alternative in biomass and carbon stocks quantification. This method could protect trees outside forests found in most parts of Africa
The design-by-adaptation approach to universal access: learning from videogame technology
This paper proposes an alternative approach to the design of universally accessible interfaces to that provided by formal design frameworks applied ab initio to the development of new software. This approach, design-byadaptation, involves the transfer of interface technology and/or design principles from one application domain to another, in situations where the recipient domain is similar to the host domain in terms of modelled systems, tasks and users. Using the example of interaction in 3D virtual environments, the paper explores how principles underlying the design of videogame interfaces may be applied to a broad family of visualization and analysis software which handles geographical data (virtual geographic environments, or VGEs). One of the motivations behind the current study is that VGE technology lags some way behind videogame technology in the modelling of 3D environments, and has a less-developed track record in providing the variety of interaction methods needed to undertake varied tasks in 3D virtual worlds by users with varied levels of experience. The current analysis extracted a set of interaction principles from videogames which were used to devise a set of 3D task interfaces that have been implemented in a prototype VGE for formal evaluation
Residents' annoyance responses to aircraft noise events
In a study conducted in the vicinity of Salt Lake City International Airport, community residents reported their annoyance with individual aircraft flyovers during rating sessions conducted in their homes. Annoyance ratings were obtained at different times of the day. Aircraft noise levels were measured, and other characteristics of the aircraft were noted by trained observers. Metrics commonly used for assessing aircraft noise were compared, but none performed significantly better than A-weighted sound pressure level. A significant difference was found between the ratings of commercial jet aircraft and general aviation propeller aircraft, with the latter being judged less annoying. After the effects of noise level were accounted for, no significant differences were found between the ratings of landings and takeoffs. Aircraft noise annoyance reactions are stronger in lowered ambient noise conditions. This is consistent with the theory that reduced nighttime and evening ambient levels could create different reactions at different times of day. After controlling for ambient noise in a multiple regression analysis, no significant differences were found between the ratings of single events obtained during the three time periods: morning, afternoon, and evenings
No Radio Afterglow from the Gamma-Ray Burst of February 28, 1997
We present radio observations of the gamma-ray burster GRB 970228 made with
the Very Large Array (VLA) and the Owens Valley Radio Observatory (OVRO)
spanning a range of postburst timescales from one to 300 days. A search for a
time-variable radio source was conducted covering an area which included a
fading X-ray source and an optical transient, both of which are thought to be
the long wavelength counterparts to the gamma-ray burst. At the position of the
optical transient sensitive limits between 10 uJy and 1 mJy can be placed on
the absence of a radio counterpart to GRB 970228 between 1.4 and 240 GHz. We
apply a simple formulation of a fireball model which has been used with some
success to reproduce the behavior of the optical and X-ray light curves. Using
this model we conclude that the radio non-detections are consistent with the
peak flux density of the afterglow lying between 20-40 uJy and it requires that
the optical flux peaked between 4 and 16 hours after the burst.Comment: ApJ Let (submitted
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