Examination of the Circle Spline Routine

The Circle Spline routine is currently being used for generating both two and three dimensional spline curves. It was developed for use in ESCHER, a mesh generating routine written to provide a computationally simple and efficient method for building meshes along curved surfaces. Circle Spline is a parametric linear blending spline. Because many computerized machining operations involve circular shapes, the Circle Spline is well suited for both the design and manufacturing processes and shows promise as an alternative to the spline methods currently supported by the Initial Graphics Specification (IGES)

Dubious Patent Reform

The 2011 America Invents Act sought to drastically improve the American patent system by creating new review processes for already issued patents. These processes were meant to reduce patent litigation costs and clear the field of “dubious patents,” all the while increasing certainty in the existence and scope of patent rights. Though this was not the first attempt to achieve these goals, Congress failed to heed the lessons of past reforms or fully take into account the costs associated with these new post-issuance review mechanisms. The result was a set of dubious reforms. This Article marshals empirical data and case-study based evidence to show that the newly created system is open to abuse, that such abuse occurs, and that the costs that Congress ignored are substantial

Active Exterior Cloaking

A new method of cloaking is presented. For two-dimensional quasistatics it is proven how a single active exterior cloaking device can be used to shield an object from surrounding fields, yet produce very small scattered fields. The problem is reduced to finding a polynomial which is approximately one within one disk and zero within a second disk, and such a polynomial is constructed. For the two-dimensional Helmholtz equation, it is numerically shown that three active exterior devices placed around the object suffice to produce very good cloaking.Comment: 4 pages, 3 figures, submitted to Physical Review Letter

Exterior optical cloaking and illusions by using active sources: a boundary element perspective

Recently, it was demonstrated that active sources can be used to cloak any objects that lie outside the cloaking devices [Phys. Rev. Lett. \textbf{103}, 073901 (2009)]. Here, we propose that active sources can create illusion effects, so that an object outside the cloaking device can be made to look like another object. invisibility is a special case in which the concealed object is transformed to a volume of air. From a boundary element perspective, we show that active sources can create a nearly "silent" domain which can conceal any objects inside and at the same time make the whole system look like an illusion of our choice outside a virtual boundary. The boundary element method gives the fields and field gradients (which can be related to monopoles and dipoles) on continuous curves which define the boundary of the active devices. Both the cloaking and illusion effects are confirmed by numerical simulations

Superantenna made of transformation media

We show how transformation media can make a superantenna that is either completely invisible or focuses incoming light into a needle-sharp beam. Our idea is based on representating three-dimensional space as a foliage of sheets and performing two-dimensional conformal maps on each shee

Olianatrivia riberai n. gen., n. sp. (Mollusca, Caenogastropoda), une Ovulidae singulière du Bartonien (Éocène moyen) de Catalogne (Espagne)

Les coquilles d’une espèce d’Ovulidae aux caractères totalement inhabituals ont été récoltés dans la partie axiale de l’anticlinal d’Oliana, en Catalogne: Olianatrivia riberai n. gen., n. sp. (Mollusca, Caenogastropoda), dont la formeet l’ornementation rappellent certaines Triviinae. En accord avec les datations chrono-stratigraphiques connues établies dans le bassin, l’âge de la faune mala-cologique, déplacée à partir d’un faciès récifal, est datée du Bartonien supérieur (Éocène moyen). Il est proposé de placer O. Riberai n.gen., n. sp. au sein des Pediculariinae, une sous-famille des Ovulidae (Cypraeoidea), à proximité de Cypropterina ceciliae (De Gregorio, 1880) du Lutétien inférieur du VéronaisPeer ReviewedPostprint (published version

RNA Viral Community in Human Feces: Prevalence of Plant Pathogenic Viruses

The human gut is known to be a reservoir of a wide variety of microbes, including viruses. Many RNA viruses are known to be associated with gastroenteritis; however, the enteric RNA viral community present in healthy humans has not been described. Here, we present a comparative metagenomic analysis of the RNA viruses found in three fecal samples from two healthy human individuals. For this study, uncultured viruses were concentrated by tangential flow filtration, and viral RNA was extracted and cloned into shotgun viral cDNA libraries for sequencing analysis. The vast majority of the 36,769 viral sequences obtained were similar to plant pathogenic RNA viruses. The most abundant fecal virus in this study was pepper mild mottle virus (PMMV), which was found in high concentrations—up to 10(9) virions per gram of dry weight fecal matter. PMMV was also detected in 12 (66.7%) of 18 fecal samples collected from healthy individuals on two continents, indicating that this plant virus is prevalent in the human population. A number of pepper-based foods tested positive for PMMV, suggesting dietary origins for this virus. Intriguingly, the fecal PMMV was infectious to host plants, suggesting that humans might act as a vehicle for the dissemination of certain plant viruses

Analysis of By-Products of N2-SF6 Gas Mixtures Sparked under Inhomogenous Field Conditions

A vast data on formation of by-products due to arc and spark decomposition of SF6 is available in literature [1–10]. But experimental work relating to N2 - SF6 gas mixtures is limited. In view of increasing application of gas mixtures, it is essential to understand the nature of by-products formed in gas mixtures. Many recent studies have highlighted the advantages of using N2-SF6 gas mixtures as a replacement to SF6 gas for High Voltage application, with a view to reduce emission of SF6 gas into the atmosphere. Majority of these studies are aimed at determining the basic characteristics of N2-SF6 gas mixtures. However, this study attempts to understand the nature and quantum of different species formed in N2-SF6 mixtures in the presence of insulating spacers when sparked under inhomogeneous field conditions

Paraumbilical collateral veins on MRI as possible protection against portal venous thrombosis in candidates for liver transplantation

Background: We retrospectively evaluate the potential protective influence of patent paraumblical vein (PUV) collaterals against portal vein (PV) thrombosis and reduced PV diameter in candidates for orthotopic liver transplant (OLT) Methods: Dynamic 3D contrast-enhanced MRI at 1.5T was obtained in 309 patients with cirrhosis without evidence of malignancy. All MR studies were reviewed by one reader for PUV collaterals, PV thrombosis and PV diameter. Statistical analysis was performed by Fisher exact tests; 50 selected studies were reviewed independently by two additional readers to determine interobserver agreement via intraclass correlation coefficient (ICC). Results: Patent PUV was noted in 119 of 309 patients (38.5%). Mean PV diameter was 13.4 ± 3.0 mm in patients with PUV compared with 11.3 ± 3.6 mm without PUV (P \u3c 0.01). Main PV thrombosis was present in 13 of 309 patients (4.2%) and significantly more frequent in those without PUV than with PUV (6.3% vs. 0.8%, P \u3c 0.05). ICC indicated almost perfect agreement among three readers for presence of PUV collaterals (ICC = 0.91) and PV thrombosis (ICC = 0.96). Conclusion: Our results suggest that patients with patent PUV appear less likely to develop main PV thrombosis or small PV diameter, suggesting a protective effect of PUV on PV patency