2,481 research outputs found
Diphenyl[2-(phenylsulfonyl)propan-2-yl]-λ5-phosphanethione
The title compound, C21H21O2PS2, was obtained from the corresponding dilithio methandiide by treatment with iodomethane. The bond lengths and angles deviate considerably from those in the dimetallated compound. These differences are most pronounced in the PCS backbone. While the title compound features C—P and C—S distances of 1.9082 (17) and 1.8348 (17) Å, respectively, the dianion showed C—Pav distances shortened by 11% [1.710 (4) Å] and C—S distances shortened by 12% [1.614 (3) Å]. Additionally, the P—C—S angle experiences a contraction by methylation of the dianion from 121.4 (2) to 111.96 (9)° in the title compound
Local Detection of Quantum Correlations with a Single Trapped Ion
As one of the most striking features of quantum mechanics, quantum
correlations are at the heart of quantum information science. Detection of
correlations usually requires access to all the correlated subsystems. However,
in many realistic scenarios this is not feasible since only some of the
subsystems can be controlled and measured. Such cases can be treated as open
quantum systems interacting with an inaccessible environment. Initial
system-environment correlations play a fundamental role for the dynamics of
open quantum systems. Following a recent proposal, we exploit the impact of the
correlations on the open-system dynamics to detect system-environment quantum
correlations without accessing the environment. We use two degrees of freedom
of a trapped ion to model an open system and its environment. The present
method does not require any assumptions about the environment, the interaction
or the initial state and therefore provides a versatile tool for the study of
quantum systems.Comment: 6 Pages, 5 Figures + 6 Pages, 1 Figure of Supplementary Materia
Linkage Evidence for a Two-Locus Inheritance of LQT-Associated Seizures in a Multigenerational LQT Family With a Novel KCNQ1 Loss-of-Function Mutation
Mutations in several genes encoding ion channels can cause the long-QT (LQT)
syndrome with cardiac arrhythmias, syncope and sudden death. Recently, mutations in
some of these genes were also identified to cause epileptic seizures in these patients, and
the sudden unexplained death in epilepsy (SUDEP) was considered to be the pathologic
overlap between the two clinical conditions. For LQT-associated KCNQ1 mutations, only
few investigations reported the coincidence of cardiac dysfunction and epileptic seizures.
Clinical, electrophysiological and genetic characterization of a large pedigree (n = 241
family members) with LQT syndrome caused by a 12-base-pair duplication in exon 8 of
the KCNQ1 gene duplicating four amino acids in the carboxyterminal KCNQ1 domain
(KCNQ1dup12; p.R360_Q361dupQKQR, NM_000218.2, hg19). Electrophysiological
recordings revealed no substantial KCNQ1-like currents. The mutation did not exhibit a
dominant negative effect on wild-type KCNQ1 channel function. Most likely, the mutant
protein was not functionally expressed and thus not incorporated into a heteromeric
channel tetramer. Many LQT family members suffered from syncopes or developed
sudden death, often after physical activity. Of 26 family members with LQT, seizures were
present in 14 (LQTplus seizure trait). Molecular genetic analyses confirmed a causative
role of the novel KCNQ1dup12 mutation for the LQT trait and revealed a strong link
also with the LQTplus seizure trait. Genome-wide parametric multipoint linkage analyses
identified a second strong genetic modifier locus for the LQTplus seizure trait in the
chromosomal region 10p14. The linkage results suggest a two-locus inheritance model
for the LQTplus seizure trait in which both the KCNQ1dup12 mutation and the 10p14
risk haplotype are necessary for the occurrence of LQT-associated seizures. The data
strongly support emerging concepts that KCNQ1 mutations may increase the risk of
epilepsy, but additional genetic modifiers are necessary for the clinical manifestation of
epileptic seizures
Holistic Compliance with Sarbanes-Oxley
The theory underlying US securities laws is that investors are helpless without reliable information [Zelizer, 2002]. When Enron\u27s collapse and other corporate frauds made it clear that practically every element of our system of safeguards failed until it was too late to repair the damage, Congress reinforced those laws by passing the Sarbanes-Oxley (SARBOX) Act [O\u27Malley, 2002]. This new law demands that C-suite executives confirm their confidence in the quality and integrity of information generated by information systems by signing the figures off personally. Under SARBOX, the Securities and Exchange Commission holds executives accountable for reliable internal controls, record retention, and fraud detection. In turn, executives are looking to information systems and to IS auditors to help them meet their regulatory responsibilities. This article discusses SARBOX mandates and the intent of regulatory agencies. That understanding lays the foundation needed to develop holistic SARBOX compliance programs with information technology and business process improvements. Holistic compliance is an enterprise-wide and long-term approach that views the new law as opportunities to improve internal controls and public reporting. Holistic compliance stands in contrast to simply complying with the rules or silo compliance; i.e., efforts scattered throughout business silos. We identify SARBOX requirements ( sections ) concerning IS and IS research. Research areas to achieve minimal compliance include methods for IS assurance and auditing, risk management, and electronic records management (ERM). Research in business intelligence, data warehousing and mining, and supply chain management are necessary for holistic compliance that improves competitive position. While research efforts in these areas are not new, regulations have made them more compelling and urgent issues for senior management
Nonlinear Spectroscopy of Controllable Many-Body Quantum Systems
We establish a novel approach to probing spatially resolved multi-time
correlation functions of interacting many-body systems, with scalable
experimental overhead. Specifically, designing nonlinear measurement protocols
for multidimensional spectra in a chain of trapped ions with single-site
addressability enables us, e.g., to distinguish coherent from incoherent
transport processes, to quantify potential anharmonicities, and to identify
decoherence-free subspaces.Comment: 12 pages, 3 figure
Measuring geometric phases with a dynamical quantum Zeno effect in a Bose-Einstein condensate
A closed-trajectory evolution of a quantum state generally imprints a phase
that contains both dynamical and geometrical contributions. While dynamical
phases depend on the reference system, geometric phase factors are uniquely
defined by the properties of the outlined trajectory. Here, we generate and
measure geometric phases in a Bose-Einstein condensate of Rb using a
combination of dynamical quantum Zeno effect and measurement-free evolution. We
show that the dynamical quantum Zeno effect can inhibit the formation of a
geometric phase without altering the dynamical phase. This can be used to
extract the geometric Aharonov-Anandan phase from any closed-trajectory
evolution without requiring knowledge or control of the Hamiltonian.Comment: 4+3 pages, 4+3 figure
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