Ab initio studies of the spin-transfer torque in tunnel junctions

We calculate the spin-transfer torque in Fe/MgO/Fe tunnel junctions and compare the results to those for all-metallic junctions. We show that the spin-transfer torque is interfacial in the ferromagnetic layer to a greater degree than in all-metallic junctions. This result originates in the half metallic behavior of Fe for the $\Delta_1$ states at the Brillouin zone center; in contrast to all-metallic structures, dephasing does not play an important role. We further show that it is possible to get a component of the torque that is out of the plane of the magnetizations and that is linear in the bias. However, observation of such a torque requires highly ideal samples. In samples with typical interfacial roughness, the torque is similar to that in all-metallic multilayers, although for different reasons.Comment: 5 pages, 4 figure

Dielectric properties of snow

The dielectric properties of snow in the radio frequency range from 100 KHz to 35 GHz are reviewed. Applicable dielectric mixing formulas are discussed and compared to available experimental data

PCPro a Novel Technology for Rapid Prototyping and Rapid Manufacturing

PCPro stands for Precise Cast Prototyping, which is a combination of casting technologies and milling. This method was developed at Fraunhofer IWS in Dresden, Germany. It is patented in Germany [1] and is applied in the USA under US 10/794,936. The main goal for this development was to shorten the process chain for making plastic prototypes accompanied by higher quality. The casting technology was integrated in a machining center in order to enable a high degree of automation and to avoid an external casting system. This means that Rapid Manufacturing can be easily implemented using such an automated combination of casting and machining. This article describes the PCPro method by means of the fabrication of sample parts. The advantages and the limitations in comparison to common Rapid Prototyping and Rapid Manufacturing process chains will be discussed. In addition, the manufacturing of a prototype machine is presented.Mechanical Engineerin

Seasonal variations of the microwave scattering properties of deciduous trees as measured in the 1-18 GHz spectral range

The author has identified the following significant results. Employing two FM-CW radar spectrometers, scattering data were acquired from stands of deciduous trees during the spring and autumn. The data suggest that the trees act as a volume scatter target particularly in the 7-18 GHz region. A comparison of data collected in spring and autumn indicates that the radar scattering coefficient, sigma deg, as measured in spring can be substantially larger (as much as 10 dB) than sigma deg as measured in the autumn

Among the Digital Luddites

I’m here to throw empirical salt on theory’s slug. In discussions of copyright or the literary marketplace, there is too much generalization. We often see the experience of one author with one book presented as a template for everyone, but book publishing doesn’t work that way. Each book is a unique product. One can take ten years to write, another ten weeks. It might be filled with photos and maps, or with none. What is true for one author will not be true for another. I am a self-employed author of serious nonfiction in the commercial marketplace. My world is summed up by an episode of The Simpsons, titled “The Front.” Bart and Lisa take Grandpa Simpson to visit the studio that makes “Itchy and Scratchy” cartoons; they’ve been submitting freelance scripts in Grandpa’s name. The studio chief says to Grandpa, “Are you sure you’re a writer? You’re so old!” Grandpa replies, “Where’s my check!” The studio chief says, “Oh, you’re a writer all right.” Self-employed writers can’t spend five minutes together without discussing money. If you think it’s because we’re greedy, let me quote The Aviator: “The only reason you don’t care about money is that you’ve always had it.” Like all of you, we want to make a living doing what we do best. We know we might fail, but we want to be able to try. But we face a structural problem. We are disaggregated individuals in a global economy dominated by large institutions that feel free to take advantage of us: huge corporations and sometimes, sadly, even universities. But our shared culture depends upon individual voices. Dissent comes from outside institutional thinking; creativity comes from the individual, often in opposition to majority opinion

North Carolina\u27s Unconstitutional Expansion of an Ancient Maxim: Using DWI Fatalities to Satisfy First-Degree Felony Murder

This Comment argues that using a traffic fatality to satisfy the felony-murder rule is inappropriate. When the State prosecutes a DWI fatality under the felony murder rule, it diminishes the concept of an ancient doctrine. If it is the goal of the State to give life sentences or the death penalty for DWI fatalities, then it is the responsibility of the North Carolina General Assembly to enact a statute specifically dictating such punishment rather than the court judicially imposing the punishment through their interpretation of the felony-murder rule

Microwave remote sensing of snow experiment description and preliminary results

The active and passive microwave responses to snow were investigated at a site near Steamboat Springs, Colorado during the February and March winter months. The microwave equipment was mounted atop truck-mounted booms. Data were acquired at numerous frequencies, polarizations, and angles of incidence for a variety of snow conditions. The experiment description, the characteristics of the microwave and ground truth instruments, and the results of a preliminary analysis of a small portion of the total data volume acquired in Colorado are documented

Effectiveness of Teriparatide Therapy for Prevention of Fractures in Glucocorticoid-Induced Osteoporosis

Background: Glucocorticoids have a wide-range of beneficial effects for treating inflammatory, allergic, and immunologic conditions. However, glucocorticoid therapy can lead to increased bone resorption and reduced bone formation by inhibiting osteoblast proliferation. This bone deterioration leads to osteoporosis. When considering therapy for prevention of fractures in glucocorticoid-induced osteoporosis (GIO), teriparatide (recombinant human parathyroid hormone 1-34) is an anabolic agent that can be used to improve bone mineral density (BMD) and prevent fractures. Due to bone deterioration caused by glucocorticoid therapy, prevention of bone fractures has significant importance. While there are several choices for therapy for prevention of GIO, the anabolic agent teriparatide could show a more significant improvement of BMD and of preventing fractures resulting from GIO. The purpose of this systematic review of the literature is to evaluate the efficacy of teriparatide in prevention of fractures that can result from glucocorticoid therapy. Methods: An extensive literature search was conducted using Medline-OVID, CINAHL, Evidence Based Medicine Reviews Multifile, and Web of Science using the search terms: teriparatide, osteoporosis, fractures, and glucocorticoids. The reference sections of each of these articles were further searched for additional relevant sources. Articles were screened and evaluated for relevance using GRADE. Results: Two studies met inclusion criteria for this systematic review that included two randomized control trials. These studies demonstrated that patients who were on teriparatide had increased BMD. Both studies also measured fracture rates and showed a decrease favoring teriparatide. Conclusion: There is sufficient evidence to recommend teriparatide as a therapeutic option for reversing the effects of glucocorticoid-induced osteoporosis by improving bone mineral density and preventing the occurrence of fractures, although there may still remain a question of safety that would warrant continued research. Keywords: teriparatide, fractures, osteoporosis, and glucocorticoids

Phenolic cutter for machining foam insulation

Pre-pregged fiber glass is an efficient abrasive for machining polystyrene and polyurethane foams. It bonds easily to any cutter base made of aluminum, steel, or phenolic, is inexpensive, and is readily available

Microflow valve control system design

A design synthesis for a microflow control system is presented based on the interrogation of an analytical model, testing, and observation. The key issues relating to controlling a microflow using a variable geometry flow channel are explored through the implementation and testing of open and closed-loop control systems. The reliance of closed-loop systems on accurate flow measurement and the need for an open-loop strategy are covered. A valve and control system capable of accurately controlling flowrates between 0.09 and 400 ml/h and with a range of 900:1 is demonstrated