1,898 research outputs found
Weak one-basedness
We study the notion of weak one-basedness introduced in recent work of Berenstein and Vassiliev. Our main results are that this notion characterises linearity in the setting of geometric þ-rank 1 structures and that lovely pairs of weakly one-based geometric þ-rank 1 struc- tures are weakly one-based with respect to þ-independence. We also study geometries arising from infinite dimensional vector spaces over division rings
Adoption of Immersive Technologies in Manufacturing SMEs – A Strategy-as-Practice Perspective on their Affordances, Constraints and Responses
Immersive technologies (ImT) provide affordances for small and medium-sized enterprises (SMEs) in the manufacturing industry, such as the enhancement and recreation of aspects of the physical world. These affordances are critical due to changes in the SMEs’ environment including increasingly virtualized collaboration and digitization of work practices. However, the adoption of ImT by manufacturing SMEs is still low. Drawing on the Technology Affordances and Constraints theory, and applying a Strategy-as-Practice approach, this study researches the adoption of ImT as a strategic response to environmental changes in German-based manufacturing SMEs. The findings reveal the critical role of constraints of ImT, which act as hindrances to implementation. Specifically, realizing the affordances of ImT requires consideration of, and responses to, the constraints manufacturing SMEs experience, including the constraints associated with the providers of ImT. Thus, this paper expands the understanding of the factors which influence implementation and strategizing of ImT in SMEs
Relation of Receptive Field Size and Salt Taste Responses in Chorda Tympani Fibers during Development a
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73728/1/j.1749-6632.1987.tb43605.x.pd
Development of chorda tympani taste responses in rat
To learn whether neurophysiological taste responses change during structural development of the gustatory system, we recorded from the chorda tympani nerve in rats aged 7 to 92 days after birth. Chemical stimuli applied to the anterior tongue included four monochloride salts, two acids, sucrose, and urea. Responses to all chemicals were obtained as early as 7 days postnatally. Developmental changes in salt, acid, and sucrose responses were observed. Relative to NaCl and LiCl, NH 4 Cl and KCl gradually decrease in effectiveness as taste stimuli; or, relative to NH 4 Cl and KCl, NaCl and LiCl become more effective stimuli. These changes are similar to those observed prenatally and postnatally in sheep. Also, relative to NaCl, citric acid, hydrochloric acid, and sucrose become less effective stimuli; or, NaCl becomes more effective as a stimulus, relative to these acids and sucrose. The period of most rapid functional change overlaps a period of rapid structural change. It seems most reasonable to hypothesize that the altering taste responses reflect developmental changes in receptor membrane composition. Since the taste system is not programmed to respond in a mature manner from the moment function begins, there is ample opportunity for changing taste experience to influence the developing taste system.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50014/1/901980105_ftp.pd
Three-Year Longitudinal Service-Learning Research Study: Preliminary Findings
Using an experimental design, this study examines the contributions of service-learning to decreased at-risk behaviors, student cognitive, social, and personal development, and academic achievement over a three-year period. During the pilot phase and Years One and Two, teachers and students from eleven different Ohio schools have been surveyed. Preliminary findings are presented
Use of Demonstration Gardens in Extension: Challenges and Benefits
Extension agents\u27 use of demonstration gardens was studied to determine how gardens are employed in horticultural programming, perceived benefits and challenges of using gardens for Extension programming, and desired competencies. Gardens are primarily used to enhance educational efforts by providing hands-on learning experiences. Greatest perceived benefits of gardens were their effectiveness as an educational delivery method, as well as their ability to provide opportunities for meaningful volunteer service and facilitate the development of partnerships. Greatest perceived challenges were availability of time, money, and volunteer support. Findings support the use of gardens as an appropriate educational strategy for Extension programming
RF Properties and Their Variations in a 3D Printed Klystron Circuit and Cavities
Presently, the manufacturing of active RF devices like klystrons is dominated
by expensive and time consuming cycles of machining and brazing. In this
article we characterize the RF properties of X-band klystron cavities and an
integrated circuit manufactured with a novel additive manufacturing process.
Parts are 3D printed in 316L stainless steel with direct metal laser sintering,
electroplated in copper, and brazed in one simple braze cycle. Standalone test
cavities and integrated circuit cavities were measured throughout the
manufacturing process. Un-tuned cavity frequency varies by less than 5% of
intended frequency, and Q factors reach above 1200. A tuning study was
performed, and unoptimized tuning pins achieved a tuning range of 138 MHz
without compromising Q. Klystron system performance was simulated with as-built
cavity parameters and realistic tuning. Together, these results show promise
that this process can be used to cheaply and quickly manufacture a new
generation of highly integrated high power vacuum devices.Comment: 8 pages, 16 figure
21cmfish: Fisher-matrix framework for fast parameter forecasts from the cosmic 21-cm signal
The 21-cm signal from neutral hydrogen in the early universe will provide unprecedented information about the first stars and galaxies. Extracting this information, however, requires accounting for many unknown astrophysical processes. Seminumerical simulations are key for exploring the vast parameter space of said processes. These simulations use approximate techniques such as excursion-set and perturbation theory to model the 3D evolution of the intergalactic medium, at a fraction of the computational cost of hydrodynamic and/or radiative transfer simulations. However, exploring the enormous parameter space of the first galaxies can still be computationally expensive. Here, we introduce 21cmfish, a Fisher-matrix wrapper for the seminumerical simulation 21cmfast. 21cmfish facilitates efficient parameter forecasts, scaling to significantly higher dimensionalities than MCMC approaches, assuming a multivariate Gaussian posterior. Our method produces comparable parameter uncertainty forecasts to previous MCMC analyses but requires ∼104 × fewer simulations. This enables a rapid way to prototype analyses adding new physics and/or additional parameters. We carry out a forecast for HERA using the largest astrophysical parameter space to date, with 10 free parameters, spanning both population II and III star formation. We find X-ray parameters for the first galaxies could be measured to sub-per cent precision, and, though they are highly degenerate, the stellar-To-halo mass relation and ionizing photon escape fraction for population II and III galaxies can be constrained to precision (logarithmic quantities). Using a principal component analysis, we find HERA is most sensitive to the product of the ionizing escape fraction and the stellar-To-halo mass fraction for population II galaxies
Correcting the z~8 Galaxy Luminosity Function for Gravitational Lensing Magnification Bias
We present a Bayesian framework to account for the magnification bias from
both strong and weak gravitational lensing in estimates of high-redshift galaxy
luminosity functions. We illustrate our method by estimating the UV
luminosity function using a sample of 97 Y-band dropouts (Lyman break galaxies)
found in the Brightest of Reionizing Galaxies (BoRG) survey and from the
literature. We find the luminosity function is well described by a Schechter
function with characteristic magnitude of ,
faint-end slope of , and number density of
. These
parameters are consistent within the uncertainties with those inferred from the
same sample without accounting for the magnification bias, demonstrating that
the effect is small for current surveys at , and cannot account for the
apparent overdensity of bright galaxies compared to a Schechter function found
recently by Bowler et al. (2014a,b) and Finkelstein et al. (2014). We estimate
that the probability of finding a strongly lensed source in our sample
is in the range depending on limiting magnitude. We identify one
strongly-lensed candidate and three cases of intermediate lensing in BoRG
(estimated magnification ) in addition to the previously known
candidate group-scale strong lens. Using a range of theoretical luminosity
functions we conclude that magnification bias will dominate wide field surveys
-- such as those planned for the Euclid and WFIRST missions -- especially at
. Magnification bias will need to be accounted for in order to derive
accurate estimates of high-redshift luminosity functions in these surveys and
to distinguish between galaxy formation models.Comment: Accepted for publication in ApJ. 20 pages, 13 figure
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