4,792 research outputs found
Navy Acquisition via leasing: policy, politics, and polemics with the Maritime Prepositioned Ships
In recent months, leasing has been prominent in the press in connection with the Air Force's ill-fated attempt to obtain the use of Boeing re-fueling tankers without buying them. Gone from memory is the early 1980's controversial Navy leasing program of Maritime Pre-positioned Ships that had a different result. This paper presents an analysis of the various issues and parties to the very creative and innovative financing on behalf of the Navy's Military Sealift Command. Still in existence today, the 1983 contracts for thirteen TAKX ships were valued at approximately $2.6 billion. While the decision is often framed as a lease versus purchase choice, the facts indicate that the option to purchase was not seen as viable at the time. In hindsight, the TAKX leasing program was successful and cost effective, despite the whirlwind of political commentary and intrigue and the dueling quantitative analyses surrounding it. However, as an unintended (or, perhaps, intended) consequence, laws and policies have since been changed so that leasing is no longer viable for financing military assets. The case presented here considers altering existing laws and regulations to once again permit leasing of military resources.Approved for public release; distribution is unlimited
Evaluasi Keberhasilan Inseminasi Buatan Pada Sapi Simental â Po (Simpo) Di Kecamatan Patean Dan Plantungan, Kabupaten Kendal, Jawa Tengah (Evaluation of Artificial Insemination Simmental â Po (Simpo) Cow in the Sub-district of Patean and Plantungan, Kend
The purpose of this research was to find out about the success of IB implementation for SIMPO cows in both of district which have different temperature and humidity based on, non return rate (NRR), conception rate(CR) and service per conception (S/C).The materials of this research was secondary data of IB implementation from 2009 until 2013 and the primary data was 60 SIMPO cows. The method that used in this study was observational and drscriptive analysis, and has passed the proportional test in order to determine the difference between the two regions, then linier regression analysis to estimate various parameters of 2014. To make the counting procedure easier and prevent humman error this research used statistical shoftware conStat. The result proved that presumption value 2014 there was a different results fo successively wereNRR28-35 83,33%; CR 30,80%; S/C 2,9 times for Patean and for Plantungan were NRR28-35 86,66%; CR 57,2%; S/C 1,5 times. The result of proportion test for CR and S/C showed different (p<0,05) but there was no differences for NRR result. The conclusion of this research that reproduction capability based on evaluation to NRR, CR and S/C of SIMPO cows in Plantungan district was better than SIMPO cows in Patean Distric
Ordering and finite-size effects in the dynamics of one-dimensional transient patterns
We introduce and analyze a general one-dimensional model for the description
of transient patterns which occur in the evolution between two spatially
homogeneous states. This phenomenon occurs, for example, during the
Freedericksz transition in nematic liquid crystals.The dynamics leads to the
emergence of finite domains which are locally periodic and independent of each
other. This picture is substantiated by a finite-size scaling law for the
structure factor. The mechanism of evolution towards the final homogeneous
state is by local roll destruction and associated reduction of local
wavenumber. The scaling law breaks down for systems of size comparable to the
size of the locally periodic domains. For systems of this size or smaller, an
apparent nonlinear selection of a global wavelength holds, giving rise to long
lived periodic configurations which do not occur for large systems. We also
make explicit the unsuitability of a description of transient pattern dynamics
in terms of a few Fourier mode amplitudes, even for small systems with a few
linearly unstable modes.Comment: 18 pages (REVTEX) + 10 postscript figures appende
Adopting an African Standpoint in HCI4D::A Provocation
While studies in HCI4D have been advanced by the shift of perspective from developmental studies to a range of other discourses, current analytical concepts for understanding the sociality of society in Africa have arguably led to some misinterpretations of the place of technology. This provocation suggests that an âAfrican Standpointâ based on a combination of various standpoint positionalities and the Wittgensteinian approach of Winch can offer conceptual and analytical sensitivities for articulating social relations, transnational engagements and the conceptualisation of technological innovation. This provides an approach for seeing and accounting for things as they are â right here, right there and right now â and not some idealised conception of an African reality
Convection-induced nonlinear-symmetry-breaking in wave mixing
We show that the combined action of diffraction and convection (walk-off) in
wave mixing processes leads to a nonlinear-symmetry-breaking in the generated
traveling waves. The dynamics near to threshold is reduced to a Ginzburg-Landau
model, showing an original dependence of the nonlinear self-coupling term on
the convection. Analytical expressions of the intensity and the velocity of
traveling waves emphasize the utmost importance of convection in this
phenomenon. These predictions are in excellent agreement with the numerical
solutions of the full dynamical model.Comment: 5 page
Breakdown of scale-invariance in the coarsening of phase-separating binary fluids
We present evidence, based on lattice Boltzmann simulations, to show that the
coarsening of the domains in phase separating binary fluids is not a
scale-invariant process. Moreover we emphasise that the pathway by which phase
separation occurs depends strongly on the relation between diffusive and
hydrodynamic time scales.Comment: 4 pages, Latex, 4 eps Figures included. (higher quality Figures can
be obtained from [email protected]
Graphene field-effect-transistors with high on/off current ratio and large transport band gap at room temperature
Graphene is considered to be a promising candidate for future
nano-electronics due to its exceptional electronic properties. Unfortunately,
the graphene field-effect-transistors (FETs) cannot be turned off effectively
due to the absence of a bandgap, leading to an on/off current ratio typically
around 5 in top-gated graphene FETs. On the other hand, theoretical
investigations and optical measurements suggest that a bandgap up to a few
hundred meV can be created by the perpendicular E-field in bi-layer graphenes.
Although previous carrier transport measurements in bi-layer graphene
transistors did indicate a gate-induced insulating state at temperature below 1
Kelvin, the electrical (or transport) bandgap was estimated to be a few meV,
and the room temperature on/off current ratio in bi-layer graphene FETs remains
similar to those in single-layer graphene FETs. Here, for the first time, we
report an on/off current ratio of around 100 and 2000 at room temperature and
20 K, respectively in our dual-gate bi-layer graphene FETs. We also measured an
electrical bandgap of >130 and 80 meV at average electric displacements of 2.2
and 1.3 V/nm, respectively. This demonstration reveals the great potential of
bi-layer graphene in applications such as digital electronics,
pseudospintronics, terahertz technology, and infrared nanophotonics.Comment: 3 Figure
Effect of Shear Flow on the Stability of Domains in Two Dimensional Phase-Separating Binary Fluids
We perform a linear stability analysis of extended domains in
phase-separating fluids of equal viscosity, in two dimensions. Using the
coupled Cahn-Hilliard and Stokes equations, we derive analytically the
stability eigenvalues for long wavelength fluctuations. In the quiescent state
we find an unstable varicose mode which corresponds to an instability towards
coarsening. This mode is stabilized when an external shear flow is imposed on
the fluid. The effect of the shear is seen to be qualitatively similar to that
found in experiments.Comment: 13 pages, RevTeX, 8 eps figures included. Submitted to Phys. Rev.
Comparison of two sample preparation methods for 1H-NMR wine profiling: Direct analysis and solid-phase extraction
This study compares two sample preparation methods: direct analysis (DA) and solid-phase extraction (SPE) for wine samples analysis by proton nuclear magnetic resonance (1H-NMR) spectroscopy. For this purpose, the profile of Mexican commercial wines was evaluated. The selected wines were produced with different grape varieties: ('Barbera', 'Nebbiolo', 'Zinfandel', 'Merlot', 'Petite Syrah', 'Cabernet Sauvignon', 'White Zinfandel' and mixture of 'Chenin blanc' and 'Colombard') coming from the principal wine-producing region of Mexico, Baja California State. DA provided faster data acquisition in comparison to SPE and preserved the original sample composition. Using DA-NMR thirty two metabolites were identified, including organic acids, amino acids, sugars, alcohols and phenolic compounds. Furthermore, SPE-NMR using a polymeric sorbent allowed to retain phenolic compounds giving a better picture on the aromatic region and eliminating major polar compounds like water, ethanol and sugars. Fourteen compounds were identified by SPE-NMR including higher alcohols, flavanols and hydroxybenzoates. A control chart for the first principal component allowed to confirm the precision of the SPE-NMR method, while a comparison of the concentration of two metabolites found in both methods was used to evaluate their recovery (20 % for isoamyl alcohol and 78 % for phenethyl alcohol). The information obtained with both methods about the main compounds and phenolic metabolites provides new insights into the metabolomic profile of wine, which could be useful in future targeted studies
Relational mobility predicts faster spread of COVID-19: a 39-country study
It has become increasingly clear that COVID-19 is transmitted between individuals. It stands to reason that the spread of the virus depends on sociocultural ecologies that facilitate or inhibit social contact. In particular, the community-level tendency to engage with strangers and freely choose friends, called relational mobility, creates increased opportunities to interact with a larger and more variable range of other people. It may therefore be associated with a faster spread of infectious diseases, including COVID-19. Here, we tested this possibility by analyzing growth curves of confirmed cases of and deaths due to COVID-19 in the first 30 days of the outbreaks in 39 countries. We found that growth was significantly accelerated as a function of a country-wise measure of relational mobility. This relationship was robust either with or without a set of control variables, including demographic variables, reporting bias, testing availability, and cultural dimensions of individualism, tightness, and government efficiency. Policy implications are also discussed
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