Search

Viruses rely upon their hosts for biosynthesis of viral RNA, DNA and protein. This dependency frequently engenders strong selection for virus genome compatibility with potential hosts, appropriate gene regulation and expression necessary for a successful infection. While bioinformatic studies have shown strong correlations between codon usage in viral and host genomes, the selective factors by which this compatibility evolves remain a matter of conjecture. Engineered to include codons with a lesser usage and/or tRNA abundance within the host, three different attenuated strains of the bacterial virus ФX174 were created and propagated via serial transfers. Molecular sequence data indicate that biosynthetic compatibility was recovered rapidly. Extensive computational simulations were performed to assess the role of mutational biases as well as selection for translational efficiency in the engineered phage. Using bacteriophage as a model system, we can begin to unravel the evolutionary processes shaping codon compatibility between viruses and their host.

(t)]; t I:We suppose that the unit velocity curve a(t) is a differentiable regular curve oforder r: Let position vector of the curve be timelike. Let the curve be a unit velocitytimelike curve (ha?(t);a?(t)i 1):The operator D; called the Hamilton operator, corresponding to a(t) is defined bythe following matrix:D H[a(t)]a

This study focused on the clinical field validity of the Rorschach comprehensive system revised DEPI and CDI indices. Forty admission protocols from two inpatient adult DSM-III-R diagnosed samples, one with Major Depressive Disorder, uncomplicated, and one with Major Depressive Disorder and concurrent Borderline Personality Disorder, were compared. Hypotheses were (a) both groups would be identified by the revised DEPI and (b) if the Depressed Borderline group was not identified by the DEPI, it would be identified by the CDI. Both hypotheses were negated, raising questions regarding the validity of the indices for use in clinical diagnosis, treatment, and clinical research.

We report the first results from a search for weakly interacting massive particles (WIMPs) in the Cryogenic Dark Matter Search (CDMS) experiment at the Soudan Underground Laboratory. Four Ge and two Si detectors were operated for 52.6 live days, providing 19.4 kg-d of Ge net exposure after cuts for recoil energies between 10--100 keV. A blind analysis was performed using only calibration data to define the energy threshold and selection criteria for nuclear-recoil candidates. Using the standard dark-matter halo and nuclear-physics WIMP model, these data set the world's lowest exclusion limits on the coherent WIMP-nucleon scalar cross-section for all WIMP masses above 15 GeV, ruling out a significant range of neutralino supersymmetric models. The minimum of this limit curve at the 90% C.L. is 4 x 10^{-43} cm^2 at a WIMP mass of 60 GeV., Comment: 4 pages, 5 figures, submitted to Phys. Rev. Lett; minor clarifications in response to referee's comments

This study focused on the clinical field validity of the Rorschach comprehensive system revised DEPI and CDI indices. Forty admission protocols from two inpatient adult DSM-III-R diagnosed samples, one with Major Depressive Disorder, uncomplicated, and one with Major Depressive Disorder and concurrent Borderline Personality Disorder, were compared. Hypotheses were (a) both groups would be identified by the revised DEPI and (b) if the Depressed Borderline group was not identified by the DEPI, it would be identified by the CDI. Both hypotheses were negated, raising questions regarding the validity of the indices for use in clinical diagnosis, treatment, and clinical research.

The Main Injector will provide an unprecedented opportunity for challenging the Standard Model. The increased fluxes available from this essential upgrade make possible neutrino experiments of great power both at the Tevatron and at intermediate energies. With a factor of six increase in flux, experiments at higher energies probe with great sensitivity the electroweak sector, test QCD, and search for rare processes which could point the way to new physics. Such experiments can make simultaneous measurements of the Standard Model {rho} parameter and sin{sup 2} {theta}{sub W} to 0.25% and 0.6%, respectively. Measurements of the radiative corrections in electroweak physics will reveal physics at the TeV mass scale. {rho} probes the Higgs sector, and deviations from its expected value would be unambiguous signals of new phenomena and possibly our first clear window into physics beyond the Standard Model. Another way to quantify these corrections is through measurements of sin{sup 2} {theta}{sub W} in different processes; comparisons among an ensemble of precise electroweak measurements can then distinguish among alternatives and pin down the sources of new phenomena. Four processes likely to be important in the coming decade are the direct boson mass measurements, Z polarization asymmetries, atomic parity violation, and neutrino-nucleon scattering. Each of these processes has a different dependence on the various sources of new physics: such phenomena as multiple Z's, supersymmetry, or technicolor are just three of many possibilities. Neutral current measurements of sin{sup 2} {theta}{sub W} and {rho} have already provided constraints on m{sub t}; improved measurements will extend their reach and help us interpret the information from the colliders. QCD tests, especially those involving the structure function xF{sub 3}, can check two fundamental predictions of the theory: the dependence of the strong-coupling constant {alpha}{sub S}(Q{sup 2}) on Q{sup 2}, and the value (and Q{sup 2} dependence) of R{sub QCD} = {sigma}{sub L}/{sigma}{sub T}. A Main Injector experiment will check the scaling violation of the theory and provide solid measurements of the gluon distributions.

Two prototype superconducting beamline dipoles have been designed, fabricated, and tested. Each has an oval-shaped bore 0.095 m × 0.146 m and has an active length of about 1 m. The windings were impregnated with epoxy under vacuum and assembled on a heavy walled bore tube which provided structural support in combination with a stainless steel wire structural banding. The total amount of structural banding utilized was the major difference between magnets. The design for the magnets is described together with test results. Performance was essentially identical with each magnet requiring 14 quenches to surpass the air core central field design point of 2.5 Wb/m2. Voltage distributions within the magnets during the quenching process were measured and controlled through utilization of a system of protective resistors. Measured results with and without the protective circuitry are given as well as calculated transients based on a simplified model.

A low current superconducting coil intended for use in a beam transport dipole magnet was built and tested. The coil design, fabrication, quench protection, and tests results are presented.