353 research outputs found
Apollo experience report the command and service module milestone review process
The sequence of the command and service module milestone review process is given, and the Customer Acceptance Readiness Review and Flight Readiness Review plans are presented. Contents of the System Summary Acceptance Documents for the two formal spacecraft reviews are detailed, and supplemental data required for presentation to the review boards are listed. Typical forms, correspondence, supporting documentation, and minutes of a board meeting are included
Evolution equations of curvature tensors along the hyperbolic geometric flow
We consider the hyperbolic geometric flow introduced by Kong and Liu [KL]. When the Riemannian
metric evolve, then so does its curvature. Using the techniques and ideas of
S.Brendle [Br,BS], we derive evolution equations for the Levi-Civita connection
and the curvature tensors along the hyperbolic geometric flow. The method and
results are computed and written in global tensor form, different from the
local normal coordinate method in [DKL1]. In addition, we further show that any
solution to the hyperbolic geometric flow that develops a singularity in finite
time has unbounded Ricci curvature.Comment: 15 page
Deformations of the hemisphere that increase scalar curvature
Consider a compact Riemannian manifold M of dimension n whose boundary
\partial M is totally geodesic and is isometric to the standard sphere S^{n-1}.
A natural conjecture of Min-Oo asserts that if the scalar curvature of M is at
least n(n-1), then M is isometric to the hemisphere S_+^n equipped with its
standard metric. This conjecture is inspired by the positive mass theorem in
general relativity, and has been verified in many special cases. In this paper,
we construct counterexamples to Min-Oo's conjecture in dimension n \geq 3.Comment: Revised version, to appear in Invent. Mat
A geometric approach to apriori estimates for optimal transport maps
A key inequality which underpins the regularity theory of optimal transport
for costs satisfying the Ma--Trudinger--Wang condition is the Pogorelov second
derivative bound. This translates to an apriori interior estimate for
smooth optimal maps. Here we give a new derivation of this estimate which
relies in part on Kim, McCann and Warren's observation that the graph of an
optimal map becomes a volume maximizing spacelike submanifold when the product
of the source and target domains is endowed with a suitable pseudo-Riemannian
geometry that combines both the marginal densities and the cost
Rotational symmetry of self-similar solutions to the Ricci flow
Let (M,g) be a three-dimensional steady gradient Ricci soliton which is
non-flat and \kappa-noncollapsed. We prove that (M,g) is isometric to the
Bryant soliton up to scaling. This solves a problem mentioned in Perelman's
first paper.Comment: Final version, to appear in Invent. Mat
A compactness theorem for scalar-flat metrics on manifolds with boundary
Let (M,g) be a compact Riemannian manifold with boundary. This paper is
concerned with the set of scalar-flat metrics which are in the conformal class
of g and have the boundary as a constant mean curvature hypersurface. We prove
that this set is compact for dimensions greater than or equal to 7 under the
generic condition that the trace-free 2nd fundamental form of the boundary is
nonzero everywhere.Comment: 49 pages. Final version, to appear in Calc. Var. Partial Differential
Equation
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Rural Vocational and Transition Assessment Practices for Students with Intellectual Disabilities: What Do Educators Really Know?
Transition planning requires quality vocational and transition assessment tailored to the student\u27s needs, strengths, preferences and interests. Limited research is currently available that addresses assessment types and use of results that rural practitioners utilize to aid in transition planning for students with intellectual disabilities (ID). A group of 71 rural educators were surveyed to determine their transition assessment understanding and practices in the rural setting. This descriptive study examined rural educatorsâ understanding of vocational and transition assessment methods used in their rural settings, the transition assessment instruments they use with students with ID, and the impact that transition assessment has in determining the needs of students with ID. The results indicate the majority of the rural educators in the study reported limited understanding in the use of assessment results for student vocational and transition planning and expressed the need for training in this area to improve outcomes for students with ID
Static flow on complete noncompact manifolds I: short-time existence and asymptotic expansions at conformal infinity
In this paper, we study short-time existence of static flow on complete
noncompact asymptotically static manifolds from the point of view that the
stationary points of the evolution equations can be interpreted as static
solutions of the Einstein vacuum equations with negative cosmological constant.
For a static vacuum we also compute the asymptotic expansions of
and at conformal infinity.Comment: 25 page
Co2+ sorption capacity indicators of La Plata regionÂŽs soils. Insights and correlations with soil properties
Notwithstanding soil act as a pollutant sink, its Co sorption capacity presents still controversial results. Here, Co2+ sorption on soil samples from La Plata (Argentina) was analyzed. Four sorption indicators were used: Kdis (estimated from the entire sorption isotherm), KF1 (estimated from the lineal part of the sorption isotherm), Kdx, (solid-solution distribution coefficient) and Kr, a dimensionless parameter recently developed. Pearson correlation coefficients between the parameters and soil properties were calculated. Significant and negative correlations with silt were obtained, while significant and positive correlations were established with clay and smectite content. Soil clay fractions were isolated and Co2+ sorption was evaluated, observing relatively high removal. The correlations with kaolinite, magnetite and Mn and Fe oxides showed debatable results: Kdis could be more sensitive than Kr to magnetite variations while Kr seems to be more sensitive to Mn changes. KF1 presented similar behavior to Kr. The studied soils presented a high Co2+ sorption capacity, making them an effective barrier of this pollutant, avoiding its passage to groundwater and crops.Fil: Montes, MarĂa Luciana. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de FĂsica; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de FĂsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de FĂsica La Plata; ArgentinaFil: Fernandez M. A. Provincia de Buenos Aires. GobernaciĂłn. ComisiĂłn de Investigaciones CientĂficas. Centro de TecnologĂa de Recursos Minerales y CerĂĄmica. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Centro de TecnologĂa de Recursos Minerales y CerĂĄmica; ArgentinaFil: Brendle, J. UniversitĂ© Haute-alsace. Institut de Science Des MatĂ©riaux de Mulhouse.; FranciaFil: Michelin, L.. UniversitĂ© Haute-alsace. Institut de Science Des MatĂ©riaux de Mulhouse.; FranciaFil: Taylor, Marcela Andrea. Universidad Nacional de La Plata. Facultad de IngenierĂa; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de FĂsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de FĂsica La Plata; ArgentinaFil: Torres Sanchez, Rosa Maria. Provincia de Buenos Aires. GobernaciĂłn. ComisiĂłn de Investigaciones CientĂficas. Centro de TecnologĂa de Recursos Minerales y CerĂĄmica. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Centro de TecnologĂa de Recursos Minerales y CerĂĄmica; Argentin
CichoĆâs diagram for uncountable cardinals
We develop a version of CichoĆâs diagram for cardinal invariants on the generalized Cantor space 2 Îș or the generalized Baire space Îș Îș , where Îș is an uncountable regular cardinal. For strongly inaccessible Îș, many of the ZFC-results about the order relationship of the cardinal invariants which hold for Ï generalize; for example, we obtain a natural generalization of the BartoszyĆskiâRaisonnierâStern Theorem. We also prove a number of independence results, both with < Îș-support iterations and Îș-support iterations and products, showing that we consistently have strict inequality between some of the cardinal invariants
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