729 research outputs found
Entanglement of Atomic Qubits using an Optical Frequency Comb
We demonstrate the use of an optical frequency comb to coherently control and
entangle atomic qubits. A train of off-resonant ultrafast laser pulses is used
to efficiently and coherently transfer population between electronic and
vibrational states of trapped atomic ions and implement an entangling quantum
logic gate with high fidelity. This technique can be extended to the high field
regime where operations can be performed faster than the trap frequency. This
general approach can be applied to more complex quantum systems, such as large
collections of interacting atoms or molecules.Comment: 4 pages, 5 figure
Dynamical Susceptibility in KDP-type Crysals above and below Tc II
The path probability method (PPM) in the tetrahedron-cactus approximation is
applied to the Slater-Takagi model with dipole-dipole interaction for
KH2PO4-type hydrogen-bonded ferroelectric crystals in order to derive a small
dip structure in the real part of dynamical susceptibility observed at the
transition temperature Tc. The dip structure can be ascribed to finite
relaxation times of electric dipole moments responsible for the first order
transition with contrast to the critical slowing down in the second order
transition. The light scattering intensity which is related to the imaginary
part of dynamical susceptibility is also calculated above and below the
transition temperature and the obtained central peak structure is consistent
with polarization fluctuation modes in Raman scattering experiments.Comment: 8 pages, 11 figure
Analysis of technology requirements and potential demand for general aviation avionics systems for operation in the 1980's
Avionics systems are identified which promise to reduce economic constraints and provide significant improvements in performance, operational capability and utility for general aviation aircraft in the 1980's
Fourier-transform electrospray instrumentation for tandem high-resolution mass spectrometry of large molecules
AbstractMass spectrometry instrumentation providing unit resolution and 10-ppm mass accuracy for molecules larger than 10 kDa was first reported in 1991. This instrumentation has now been improved with a 6.2-T magnet replacing that of 2.8 T, a more efficient vacuum system, ion injection with controlled ion kinetic energies, accumulated ion trapping with an open-cylindrical ion cell, acquisition of 2M data points, and updated electrospray apparatus. The resulting capabilities include resolving power of 5 × 105 for a 29-kDa protein, less than 1-ppm mass measuring error, and dissociation of protein molecular ions to produce dozens of fragment ions whose exact masses can be identified from their mass-to-charge ratio values and isotopic peak spacing
Management of multi- and extensively drug-resistant tuberculosis in Ukraine: how well are we doing?
Setting: A tertiary care facility in Ukraine, a high multi- and extensively drug-resistant tuberculosis (MDR/XDR-TB) burden country. Objectives: To assess the management and treatment outcomes of MDR, pre-XDR-TB and XDR-TB. Design: Cohort study using programme data, 2006–2011. Results: Of 484 individuals with drug-resistant TB, 217 (45%) had MDR-, 153 (32%) pre-XDR- and 114 (24%) XDR-TB. Of all resistant types completing the intensive phase of treatment, 322 (67%) were alive and had culture converted. This included 157 (72%) with MDR- and 61 (54%) with XDR-TB. At the end of the continuation phase of treatment, 106 (22%) had treatment success and 378 (78%) had unfavourable outcomes, including 110 (23%) failures, 21 (4%) deaths, 71 (15%) losses to follow-up and 176 (36%) with an unknown outcome. This was associated with more than one lung cavity being affected, a history of treatment with second-line anti-tuberculosis drugs, poor adherence and XDR-TB. A total of 226 (47%) patients reported at least one adverse drug reaction, the most common being gastrointestinal and vestibular toxicity. Conclusion: Outcomes of MDR- and XDR-TB were satisfactory in the intensive phase; however, this was not sustained during the ambulatory period. If we are to do better, urgent measures are needed to improve ambulatory management, including making safer, shorter and more effective drug regimens available
Achievement Goal
Achievement goals are self-regulatory commitments that provide direction to individuals as they interpret and respond to competence-relevant situations. Four types of achievement goals have been the primary focus of the literature: Masteryapproach goals (master a task; improve over time), performance-approach goals (outperform others), mastery-avoidance goals (not fall short of mastering a task; not decline over time), and performance-avoidance goals (not be outperformed by others)
An enrichment protocol and analysis pipeline for long read sequencing of the hepatitis B virus transcriptome
Hepatitis B virus (HBV) is one of the smallest human DNA viruses and its 3.2 Kb genome encodes multiple overlapping open reading frames, making its viral transcriptome challenging to dissect. Previous studies have combined quantitative PCR and Next Generation Sequencing to identify viral transcripts and splice junctions, however the fragmentation and selective amplification used in short read sequencing precludes the resolution of full length RNAs. Our study coupled an oligonucleotide enrichment protocol with state-of-the-art long read sequencing (PacBio) to identify the repertoire of HBV RNAs. This methodology provides sequencing libraries where up to 25 % of reads are of viral origin and enable the identification of canonical (unspliced), non-canonical (spliced) and chimeric viral-human transcripts. Sequencing RNA isolated from de novo HBV infected cells or those transfected with 1.3 × overlength HBV genomes allowed us to assess the viral transcriptome and to annotate 5' truncations and polyadenylation profiles. The two HBV model systems showed an excellent agreement in the pattern of major viral RNAs, however differences were noted in the abundance of spliced transcripts. Viral-host chimeric transcripts were identified and more commonly found in the transfected cells. Enrichment capture and PacBio sequencing allows the assignment of canonical and non-canonical HBV RNAs using an open-source analysis pipeline that enables the accurate mapping of the HBV transcriptome
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