20,480 research outputs found
Technological trends affecting the manufacturing sector of New York City
The author concludes that manufacturing is still a vital part of New York City's economy, despite substantial job losses in this sector over the past two decades. An influx of skilled immigrants, the use of advanced technologies in production processes, and the ability to respond rapidly to global markets give New York City a strong future in manufacturing high-value goods.New York (N.Y.) ; Technology ; Federal Reserve District, 2nd
Parity fluctuations in stellar dynamos
Observations of the solar butterfly diagram from sunspot records suggest
persistent fluctuation in parity, away from the overall, approximately dipolar
structure. We use a simple mean-field dynamo model with a solar-like rotation
law, and perturb the -effect. We find that the parity of the magnetic
field with respect to the rotational equator can demonstrate what we describe
as resonant behaviour, while the magnetic energy behaves in a more or less
expected way. We discuss possible applications of the phenomena in the context
of various deviations of the solar magnetic field from dipolar symmetry, as
reported from analysis of archival sunspot data. We deduce that our model
produces fluctuations in field parity, and hence in the butterfly diagram, that
are consistent with observed fluctaions in solar behaviour
Anisotropic dark energy and CMB anomalies
We investigate the breaking of global statistical isotropy caused by a dark
energy component with an energy-momentum tensor which has point symmetry, that
could represent a cubic or hexagonal crystalline lattice. In such models
Gaussian, adiabatic initial conditions created during inflation can lead to
anisotropies in the cosmic microwave background whose spherical harmonic
coefficients are correlated, contrary to the standard assumption. We develop an
adaptation of the line of sight integration method that can be applied to
models where the background energy-momentum tensor is isotropic, but whose
linearized perturbations are anisotropic. We then show how this can be applied
to the cases of cubic and hexagonal symmetry. We compute quantities which show
that such models are indistinguishable from isotropic models even in the most
extreme parameter choices, in stark contrast to models with anisotropic initial
conditions based on inflation. The reason for this is that the dark energy
based models contribute to the CMB anistropy via the inegrated Sachs-Wolfe
effect, which is only relevent when the dark energy is dominant, that is, on
the very largest scales. For inflationary models, however, the anisotropy is
present on all scales.Comment: 18 pages, 9 figure
Reversals of the solar dipole
During a solar magnetic field reversal the magnetic dipole moment does not
vanish, but migrates between poles, in contradiction to the predictions of
mean-field dynamo theory. We try to explain this as a consequence of magnetic
fluctuations. We exploit the statistics of fluctuations to estimate observable
signatures. Simple statistical estimates, taken with results from mean-field
dynamo theory, suggest that a non-zero dipole moment may persist through a
global field reversal. Fluctuations in the solar magnetic field may play a key
role in explaining reversals of the dipolar component of the field.Comment: 1 figure, 4 page
Prevalence of autism spectrum disorder symptomatology and related behavioural characteristics in persons with Down syndrome
Studies on the hill reaction activity of soluble chloroplast extracts final report
Hill reaction activity of soluble chloroplast extracts from spinac
Dynamic characteristics of single crystal SSME blades
The Space Shuttle Main Engine (SSME) High Pressure Fuel Turbopump (HPFTP) blades are currently manufactured using a directionally solidified (DS) material, MAR-M-246+Hf. However, a necessity to reduce the occurrence of fatigue cracking within the DS blades has lead to an interest in the use of a single crystal (SC) material, PWA-1480. A study was initiated to determine the dynamic characteristics of the HPFTP blades made of SC material and find possible critical engine order excitations. This study examined both the first and second stage drive turbine blades of the HPFTP. The dynamic characterization was done analytically as well as experimentally. The analytical study examined the SC first stage HPFTP blade dynamic characteristics under typical operating conditions. The blades were analyzed using MSC/NASTRAN and a finite element model. Two operating conditions, 27500 RPM and 35000 RPM, were investigated
Knowledge Capital, Intangible Assets, and Leverage: Evidence from U.S. Agricultural Biotechnology Firms
Agricultural biotechnology firms are high technology companies. Firms in general, and high technology firms in particular, are a set of both assets in place and growth opportunities. This has important implications for managerial decision-making. Knowledge capital motivates exploitation of growth options, which affects firm cash flow. In turn, the level and volatility of firm cash flow influences firm financing decisions. Previous studies suggest that knowledge capital can influence both the location and capital structure of firms in the biotechnology industry. However, empirical analysis has not extended to agricultural biotechnology firms. This research helps in understanding the role of knowledge capital and other intangible assets in capital structure decisions of U.S. agricultural biotechnology firms. Quantitative results indicate that leverage is negatively related to growth and nondebt tax shields. Asset tangibility, size, profitability, and uniqueness are positively related to leverage. Using various characterizations of leverage, our models explain up to approximately 75% of the variation in leverage. Empirically generated elasticities buttress the importance of intangible assets such as knowledge capital and tax shields in capital structure choice. This analysis adds a significant new component to understanding the financing decisions of agricultural biotechnology firms.Capital structure, Agricultural biotechnology, Knowledge capital, Intangible assets, Agribusiness,
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