Uncertainty in Measurements of Distance

Ng and van Dam have argued that quantum theory and general relativity give a lower bound of L^{1/3} L_P^{2/3} on the uncertainty of any distance, where L is the distance to be measured and L_P is the Planck length. Their idea is roughly that to minimize the position uncertainty of a freely falling measuring device one must increase its mass, but if its mass becomes too large it will collapse to form a black hole. Here we show that one can go below the Ng-van Dam bound by attaching the measuring device to a massive elastic rod. Relativistic limitations on the rod's rigidity, together with the constraint that its length exceeds its Schwarzschild radius, imply that zero-point fluctuations of the rod give an uncertainty greater than or equal to L_P.Comment: 5 pages LaTe

Calculating fertilizer value of supplemental feed for cattle on pasture (2006)

Most cattle maintained on pasture receive supplemental feed during some portion of the year. Supplements are commonly fed to grazing cattle when pasture forage quality and quantity are below animal requirements

Presynchronizing PGF2α and GnRH injections before timed artificial insemination CO-Synch + CIDR program

Fixed-time artificial insemination is an effective management tool that reduces the labor associated with more conventional artificial insemination programs requiring detection of estrus. The 7-day CO-Synch + controlled internal drug release (CIDR) insert protocol has been shown to effectively initiate estrus and ovulation in cycling and non-cycling suckled beef cows, producing pregnancy rates at or greater than 50% in beef cows. The gonadotropin-releasing hormone (GnRH) injection that begins the CO-Synch + CIDR program initiates ovulation in a large proportion of cows, particularly anestrous cows. The CIDR, which releases progesterone intravaginally, prevents short estrous cycles that usually follow the first postpartum ovulation in beef cows. Our hypothesis was that inducing estrus with a prostaglandin injection followed 3 days later with a GnRH injection, 7 days before applying the 7-day CO-Synch + CIDR protocol, might increase the percentage of cycling cows that would exhibit synchronous follicular waves after the onset of the CO-Synch + CIDR protocol. We also hypothesized that the additional GnRH injection would increase the percentage of anestrous cows that would ovulate, thereby increasing pregnancy outcomes

The Quandary of Serving Multiple Masters: An Institutional Exploratory Analysis of Publishing in Business Law

Notwithstanding published articles on the nature and quality of research and scholarship in practically every other business discipline, to date there has been little systematic evaluation of relevant journals in the business law discipline. This deficiency is due, in part, to the fact that business law may still be described as a developing discipline. Thus, the focus of this article is on delineating the nature of research and scholarship within the business law discipline. Specifically, the publishing practices of business law faculty from academic institutions that were members of the Association to Advance Collegiate Schools of Business (AACSB International), the premier international accrediting body for schools of business, were examined. The comparative perspective developed in this study provides a wide-ranging view of factors related to both the qualitative and quantitative aspects of research and scholarship among business law scholars

DeepLine: AutoML Tool for Pipelines Generation using Deep Reinforcement Learning and Hierarchical Actions Filtering

Automatic machine learning (AutoML) is an area of research aimed at automating machine learning (ML) activities that currently require human experts. One of the most challenging tasks in this field is the automatic generation of end-to-end ML pipelines: combining multiple types of ML algorithms into a single architecture used for end-to-end analysis of previously-unseen data. This task has two challenging aspects: the first is the need to explore a large search space of algorithms and pipeline architectures. The second challenge is the computational cost of training and evaluating multiple pipelines. In this study we present DeepLine, a reinforcement learning based approach for automatic pipeline generation. Our proposed approach utilizes an efficient representation of the search space and leverages past knowledge gained from previously-analyzed datasets to make the problem more tractable. Additionally, we propose a novel hierarchical-actions algorithm that serves as a plugin, mediating the environment-agent interaction in deep reinforcement learning problems. The plugin significantly speeds up the training process of our model. Evaluation on 56 datasets shows that DeepLine outperforms state-of-the-art approaches both in accuracy and in computational cost

Microfocal X-Ray Computed Tomography Post-Processing Operations for Optimizing Reconstruction Volumes of Stented Arteries During 3D Computational Fluid Dynamics Modeling

Restenosis caused by neointimal hyperplasia (NH) remains an important clinical problem after stent implantation. Restenosis varies with stent geometry, and idealized computational fluid dynamics (CFD) models have indicated that geometric properties of the implanted stent may differentially influence NH. However, 3D studies capturing the in vivo flow domain within stented vessels have not been conducted at a resolution sufficient to detect subtle alterations in vascular geometry caused by the stent and the subsequent temporal development of NH. We present the details and limitations of a series of post-processing operations used in conjunction with microfocal X-ray CT imaging and reconstruction to generate geometrically accurate flow domains within the localized region of a stent several weeks after implantation. Microfocal X-ray CT reconstruction volumes were subjected to an automated program to perform arterial thresholding, spatial orientation, and surface smoothing of stented and unstented rabbit iliac arteries several weeks after antegrade implantation. A transfer function was obtained for the current post-processing methodology containing reconstructed 16 mm stents implanted into rabbit iliac arteries for up to 21 days after implantation and resolved at circumferential and axial resolutions of 32 and 50 μm, respectively. The results indicate that the techniques presented are sufficient to resolve distributions of WSS with 80% accuracy in segments containing 16 surface perturbations over a 16 mm stented region. These methods will be used to test the hypothesis that reductions in normalized wall shear stress (WSS) and increases in the spatial disparity of WSS immediately after stent implantation may spatially correlate with the temporal development of NH within the stented region

The Effect Of Image Resolution On Fluid Flow Simulations In Porous Media

Realistic simulations of flow in porous media are dependent upon having a three-dimensional, high resolution image of pore structure which is difficult to obtain. So, we ask the question, "How fine a resolution is necessary to adequately model flow in porous media?" To find the answer, we take a 7.5 p,m resolution image and coarsen it to five different resolutions. Lattice gas simulations are performed on each image. From the simulation results, we observe changes in permeability and velocity fields as the resolution is altered. The results show permeability varies by a factor of 5 over the resolution range. Flow paths change as the resolution is changed. We also find that the image processing has a large impact on the outcome of the simulations.Massachusetts Institute of Technology. Borehole Acoustics and Logging ConsortiumMassachusetts Institute of Technology. Earth Resources Laboratory. Reservoir Delineation Consortiu

Fluid Flow In Porous Media: NMR Imaging And Numerical Simulation

We use nuclear magnetic resonance (NMR) imaging to obtain a three-dimensional image of the pore structure in a limestone core, 4.5 mm in diameter and 10 mm in length, with a resolution of 40 μm. This image is converted into boundary conditions for simulation of fluid flow through the rock using the lattice gas method. The computed permeability is several orders of magnitude lower than the laboratory measured permeability, most likely a result of the image resolution being too coarse to resolve the smaller pore throats, which are believed to be significant for flow in this sample.Saudi AramcoMassachusetts Institute of Technology. Borehole Acoustics and Logging ConsortiumMassachusetts Institute of Technology. Earth Resources Laboratory. Reservoir Delineation Consortiu