Static performance of a 13.97 cm (5.5 inch) diameter model VTOL lift fan

A tip-turbine-driven fan of the type currently being used in wind tunnel tests of VTOL lift fan models was tested. Values of thrust, weight flow, exit total and static pressure, exit swirl angle, and turbine temperature drop were measured as a function of fan speed for several inlet and exit configurations. A standard fan performance map was also obtained

Initial states and infrared physics in locally de Sitter spacetime

The long wavelength physics in a de Sitter region depends on the initial quantum state. While such long wavelength physics is under control for massive fields near the Hartle-Hawking vacuum state, such initial states make unnatural assumptions about initial data outside the region of causal contact of a local observer. We argue that a reasonable approximation to a maximum entropy state, one that makes minimal assumptions outside an observer's horizon volume, is one where a cutoff is placed on a surface bounded by timelike geodesics, just outside the horizon. For sufficiently early times, such a cutoff induces secular logarithmic divergences with the expansion of the region. For massive fields, these effects sum to finite corrections at sufficiently late times. The difference between the cutoff correlators and Hartle-Hawking correlators provides a measure of the theoretical uncertainty due to lack of knowledge of the initial state in causally disconnected regions. These differences are negligible for primordial inflation, but can become significant during epochs with very long-lived de Sitter regions, such as we may be entering now.Comment: 19 pages, 4 figures, references adde

Probabilistic Search for Object Segmentation and Recognition

The problem of searching for a model-based scene interpretation is analyzed within a probabilistic framework. Object models are formulated as generative models for range data of the scene. A new statistical criterion, the truncated object probability, is introduced to infer an optimal sequence of object hypotheses to be evaluated for their match to the data. The truncated probability is partly determined by prior knowledge of the objects and partly learned from data. Some experiments on sequence quality and object segmentation and recognition from stereo data are presented. The article recovers classic concepts from object recognition (grouping, geometric hashing, alignment) from the probabilistic perspective and adds insight into the optimal ordering of object hypotheses for evaluation. Moreover, it introduces point-relation densities, a key component of the truncated probability, as statistical models of local surface shape.Comment: 18 pages, 5 figure

Comments on the black hole information problem

String theory provides numerous examples of duality between gravitational theories and unitary gauge theories. To resolve the black hole information paradox in this setting, it is necessary to better understand how unitarity is implemented on the gravity side. We argue that unitarity is restored by nonlocal effects whose initial magnitude is suppressed by the exponential of the Bekenstein-Hawking entropy. Time-slicings for which effective field theory is valid are obtained by demanding the mutual back-reaction of quanta be small. The resulting bounds imply that nonlocal effects do not lead to observable violations of causality or conflict with the equivalence principle for infalling observers, yet implement information retrieval for observers who stay outside the black hole.Comment: 18 pages, 2 figures, revtex, v2 figure added and some improvements to presentatio

Magneto-Transport in the Two-Dimensional Lorentz Gas

We consider the two-dimensional Lorentz gas with Poisson distributed hard disk scatterers and a constant magnetic field perpendicular to the plane of motion. The velocity autocorrelation is computed numerically over the full range of densities and magnetic fields with particular attention to the percolation threshold between hopping transport and pure edge currents. The Ohmic and Hall conductance are compared with mode-coupling theory and a recent generalized kinetic equation valid for low densities and small fields. We argue that the long time tail as $t^{-2}$ persists for non-zero magnetic field.Comment: 7 pages, 14 figures. Uses RevTeX and epsfig.sty. Submitted to Physical Review

The Performance of Alfalfa Synthetics in the First and Advanced Generations

During alfalfa breeding investigations conducted at the Nebraska Agricultural Experiment Station, numerous superior clones were selected and tested as clones, and in polycross progeny tests. Information was needed on the performance of synthetic varieties in the first and advanced generations, on the optimum number of clones to include in a synthetic variety, and on parent-progeny relationships. Clones with high general combining ability for forage yield as measured by polycross progeny tests, and in certain instances specific combining ability based on single-cross tests, were intercrossed in various ways to produce synthetic varieties. A group of synthetics varying in number of parents from 2 to 6 clones, having in some instances certain clones as common parents, was tested initially in the first generation of synthesis (referred to as Syn-1 from here on), later in the Syn-1 versus the Syn-2, and in some instances in the Syn-1, Syn-2, and Syn-3, and ultimately in the Syn-1,-2,-3, and -4 generations. The purposes of this bulletin are to report (1) comparative results obtained in yield trials involving the Syn-1,-2,-3, and -4 generations of 5 two-clone and 14 multiple-clone synthetics at Lincoln, Nebraska, and Ithaca, New York, and (2) parent-progeny relationships

3DFeat-Net: Weakly Supervised Local 3D Features for Point Cloud Registration

In this paper, we propose the 3DFeat-Net which learns both 3D feature detector and descriptor for point cloud matching using weak supervision. Unlike many existing works, we do not require manual annotation of matching point clusters. Instead, we leverage on alignment and attention mechanisms to learn feature correspondences from GPS/INS tagged 3D point clouds without explicitly specifying them. We create training and benchmark outdoor Lidar datasets, and experiments show that 3DFeat-Net obtains state-of-the-art performance on these gravity-aligned datasets.Comment: 17 pages, 6 figures. Accepted in ECCV 201

Fully Off-shell Effective Action and its Supersymmetry in Matrix Theory

As a step toward clarification of the power of supersymmetry (SUSY) in Matrix theory, a complete calculation, including all the spin effects, is performed of the effective action of a probe D-particle, moving along an arbitrary trajectory in interaction with a large number of coincident source D-particles, at one loop at order 4 in the derivative expansion. Furthermore, exploiting the SUSY Ward identity developed previously, the quantum-corrected effective supersymmetry transformation laws are obtained explicitly to the relevant order and are used to verify the SUSY-invariance of the effective action. Assuming that the agreement with 11-dimensional supergravity persists, our result can be regarded as a prediction for supergravity calculation, which, yet unavailable, is known to be highly non-trivial.Comment: 27 page

LMP1 of Epstein-Barr virus induces proliferation of primary mouse embryonic fibroblasts and cooperatively transforms the cells with a p16-insensitive CDK4 oncogene

The latent membrane protein LMP1 of Epstein-Barr virus (EBV) is often present in EBV-associated malignancies including nasopharyngeal carcinoma and Hodgkin's lymphoma. Previous work demonstrates that the LMP1 gene of EBV is sufficient to transform certain established rodent fibroblast cell lines and to induce the tumorigenicity of some human epithelial cell lines. In addition, LMP1 plays pleiotropic roles in cell growth arrest, differentiation, and apoptosis, depending on the background of the target cells. To examine the roles of LMP1 in cell proliferation and growth regulation in primary culture cells, we constructed a recombinant retrovirus containing an LMP1 gene. With this retrovirus, LMP1 was shown to stimulate the proliferation of primary mouse embryonic fibroblasts (MEF cells). It has a mitogenic activity for MEF cells, as demonstrated by an immediate induction of cell doubling time, In addition, it significantly extends the passage number of MEF cells to more than 30 after retroviral infection, compared with less than 5 for uninfected MEF cells. Furthermore, LMP1 cooperates with a pl6-insensitive CDK4(R24C) oncogene in transforming MEF cells. Our results provide the first evidence of the abilities of the LMP1 gene, acting alone, to effectively induce the proliferation of primary MEF cells and of its cooperativity with another cellular oncogene in transforming primary cells