9,537 research outputs found
DNA as Patentable Subject Matter and a Narrow Framework for Addressing the Perceived Problems Caused by Gene Patents
Concerns about the alleged harmful effects of gene patents— including hindered research and innovation and impeded patient access to high-quality genetic diagnostic tests—have resulted in overreactions from the public and throughout the legal profession. These overreactions are exemplified by Association for Molecular Pathology v. U.S. Patent and Trademark Office, a 2010 case in the Southern District of New York that held that isolated DNA is unpatentable subject matter under 35 U.S.C. § 101. The problem with these responses is that they fail to adequately consider the role that gene patents and patents on similar biomolecules play in facilitating investment in the costly and risky developmental processes required to transform the underlying inventions into marketable products. Accordingly, a more precisely refined solution is advisable. This Note proposes a narrowly tailored set of solutions to address the concerns about gene patents without destroying the incentives for companies to create and commercialize inventions derived from these and similar patents
Experimental tests for macroscopic phase coherence in magnetic-quasiparticle condensates of insulating spin systems
For most kinds of already known Bose-Einstein condensates experimental
evidence for the existence of a macroscopic coherent quantum state has been
provided, e.g., from the observation of interference phenomena, the formation
vortices, the detection of Josephson effects, or even by the manifestation of
superfluid behaviour. However, none of these hallmarks for a true, macroscopic
phase-coherent state has ever been reported for any insulating spin system in a
solid in which magnetic bosonic quasiparticles are thought to condense close to
a quantum critical point. We describe an attempt to detect superfluid behaviour
in TlCuCl3, and discuss in more detail a proposal for an experiment in which
the a.c. Josephson effect can be probed by using a device composed of two
weakly coupled magnetic insulators with different critical fields. We conclude
that the detection of the a.c. Josephson effect is feasible for a proper choice
of compounds with realistic material parameters.Comment: 6 pages, 2 figure
Anomalous He-Gas High-Pressure Studies on Superconducting LaO1-xFxFeAs
AC susceptibility measurements have been carried out on superconducting
LaO1-xFxFeAs for x=0.07 and 0.14 under He-gas pressures to about 0.8 GPa. Not
only do the measured values of dTc/dP differ substantially from those obtained
in previous studies using other pressure media, but the Tc(P) dependences
observed depend on the detailed pressure/temperature history of the sample. A
sizeable sensitivity of Tc(P) to shear stresses provides a possible
explanation
Studies of superconductivity and structure for CaC6 to pressures above 15 GPa
The dependence of the superconducting transition temperature Tc of CaC6 has
been determined as a function of hydrostatic pressure in both helium-loaded gas
and diamond-anvil cells to 0.6 and 32 GPa, respectively. Following an initial
increase at the rate +0.39(1) K/GPa, Tc drops abruptly from 15 K to 4 K at 10
GPa. Synchrotron x-ray measurements to 15 GPa point to a structural transition
near 10 GPa from a rhombohedral to a higher symmetry phase
Microscopic theory for the glass transition in a system without static correlations
We study the orientational dynamics of infinitely thin hard rods of length L,
with the centers-of-mass fixed on a simple cubic lattice with lattice constant
a.We approximate the influence of the surrounding rods onto dynamics of a pair
of rods by introducing an effective rotational diffusion constant D(l),l=L/a.
We get D(l) ~ [1-v(l)], where v(l) is given through an integral of a
time-dependent torque-torque correlator of an isolated pair of rods. A glass
transition occurs at l_c, if v(l_c)=1. We present a variational and a
numerically exact evaluation of v(l).Close to l_c the diffusion constant
decreases as D(l) ~ (l_c-l)^\gamma, with \gamma=1. Our approach predicts a
glass transition in the absence of any static correlations, in contrast to
present form of mode coupling theory.Comment: 6 pages, 3 figure
String breaking with dynamical Wilson fermions
We present results of our ongoing determination of string breaking in full
QCD with N_f=2 Wilson fermions. Our investigation of the fission of the static
quark-antiquark string into a static-light meson-antimeson system is based on
dynamical configurations of size 24^3 x 40 produced by the TxL collaboration.
Combining various optimization methods we determine the matrix elements of the
two-by-two system with so far unprecedented accuracy. The all-to-all light
quark propagators occurring in the transition element are computed from
eigenmodes of the Hermitian Wilson-Dirac matrix complemented by stochastic
estimates in the orthogonal subspace. We observe a clear signature for
level-splitting between ground state and excited potential. Thus, for the first
time, string breaking induced by sea quarks is observed in a simulation of
4-dimensional lattice-QCD.Comment: 3 pages, 3 figures, contribution to Lattice 200
Tables of joint probabilities useful in evaluating mixed acceptance sampling plans
Tables of joint probabilities useful in evaluating mixed acceptance sampling plan
Method and apparatus for producing microshells
A method is described for forming hollow particles, or shells, of extremely small size. The shell material is heated to a molten temperature in the presence of a gas that is at least moderately soluble in the shell material, to form a solution of the molten shell material and the soluble gas. The solution is atomized to form a multiplicity of separate droplets that are cooled while in free fall. Cooling of a droplet from the outside traps the desolved gas and forces it to form a gas bubble at the center of the droplet which now forms a gas filled shell. The shell is reheated and then cooled in free fall, in an environment having a lower pressure than the gas pressure in the shell. This causes expansion of the shell and the formation of a shell having a small wall thickness compared to its diameter
Coaxial prime focus feeds for paraboloidal reflectors
A TE11 - TM11 dual mode coaxial feed for use in prime focus paraboloidal antenna systems is investigated. The scattering matrix parameters of the internal bifurcation junction was determined by the residue calculus technique. The scattering parameters and radiation fields of the aperture were found from the Weinstein solution. The optimum modeing ratio for minimum cross-polarization was determined along with the corresponding optimum feed dimensions. A peak cross-polarization level of -58 dB is predicted. The frequency characteristics were also investigated and a bandwidth of 5% is predicted over which the cross-polarization remains below -30 dB, the input VSWR is below 1.15, and the phase error is less than 10 deg. Theoretical radiation patterns and efficiency curves for a paraboloidal reflector illuminated by this feed were computed. The predicted sidelobe level is below -30 dB and aperture efficiencies greater than 70% are possible. Experimental results are also presented that substantiates the theoretical results. In addition, experimental results for a 'short-cup' coaxial feed are given. The report includes extensive design data for the dual-mode feed along with performance curves showing cross-polarization as a function of feed parameters. The feed is useful for low-cost ground based receiving antennas for use in direct television satellite broadcasting service
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