Ultracold molecules: vehicles to scalable quantum information processing

We describe a novel scheme to implement scalable quantum information processing using Li-Cs molecular state to entangle $^{6}$Li and $^{133}$Cs ultracold atoms held in independent optical lattices. The $^{6}$Li atoms will act as quantum bits to store information, and $^{133}$Cs atoms will serve as messenger bits that aid in quantum gate operations and mediate entanglement between distant qubit atoms. Each atomic species is held in a separate optical lattice and the atoms can be overlapped by translating the lattices with respect to each other. When the messenger and qubit atoms are overlapped, targeted single spin operations and entangling operations can be performed by coupling the atomic states to a molecular state with radio-frequency pulses. By controlling the frequency and duration of the radio-frequency pulses, entanglement can either be created or swapped between a qubit messenger pair. We estimate operation fidelities for entangling two distant qubits and discuss scalability of this scheme and constraints on the optical lattice lasers

Phase Control of Trapped Ion Quantum Gates

There are several known schemes for entangling trapped ion quantum bits for large-scale quantum computation. Most are based on an interaction between the ions and external optical fields, coupling internal qubit states of trapped-ions to their Coulomb-coupled motion. In this paper, we examine the sensitivity of these motional gate schemes to phase fluctuations introduced through noisy external control fields, and suggest techniques to suppress the resulting phase decoherence.Comment: 21 pages 12 figure

Magneto-optical Trapping of Cadmium

We report the laser-cooling and confinement of Cd atoms in a magneto-optical trap, and characterize the loading process from the background Cd vapor. The trapping laser drives the 1S0-1P1 transition at 229 nm in this two-electron atom and also photoionizes atoms directly from the 1P1 state. This photoionization overwhelms the other loss mechanisms and allows a direct measurement of the photoionization cross section, which we measure to be 2(1)x10^(-16)cm^(2) from the 1P1 state. When combined with nearby laser-cooled and trapped Cd^(+) ions, this apparatus could facilitate studies in ultracold interactions between atoms and ions.Comment: 8 pages, 11 figure

Notes about the Caratheodory number

In this paper we give sufficient conditions for a compactum in $\mathbb R^n$ to have Carath\'{e}odory number less than $n+1$, generalizing an old result of Fenchel. Then we prove the corresponding versions of the colorful Carath\'{e}odory theorem and give a Tverberg type theorem for families of convex compacta

The characterization of depressive disorders in serious juvenile offenders

The authors systematically evaluated a selected population of juvenile offenders for the prevalence of affective disorders. Seventy-one (40 male, 31 female) serious juvenile offenders were interviewed using the Schedule for Affective Disorders and Schizophrenia (SADS). They were then diagnosed using the Research Diagnostic Criteria (RDC) and the DSM-III. The Hamilton Rating Scales (HRS), Carroll Self-Rating Scale (CSRS), and Global Rating Scale for Depression (GRS) were also obtained for each subject. Eleven (15%) subjects were diagnosed as having an active major depressive disorder (MDDa), 6 (8%) subjects were diagnosed as having a major depressive disorder in remission (MDDr), and 9 (13%) as having a minor depressive disorder (mDD). The HRS, CSRS, and GRS differentiated the MDDa from the other three groups including MDDr, mDD and all other psychiatric diagnoses. RDC subtypes of depressive disorders were identified in those juvenile offenders with active major depressive disorders (MDDa) and compared to a population of hospitalized adolescents with major depressive disorders. There were significant differences in the distribution of the subtypes identified. Secondary, gitated and endogenous subtypes occured significantly more often. The diagnostic, prognostic and therapeutic significance of these findings are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24911/1/0000338.pd

Baseline White Matter Hyperintensities and Hippocampal Volume are Associated With Conversion From Normal Cognition to Mild Cognitive Impairment in the Framingham Offspring Study.

INTRODUCTION: We examined associations between magnetic resonance imaging (MRI) markers of cerebrovascular disease and neurodegeneration with mild cognitive impairment (MCI) diagnosis at baseline and conversion from normal cognition to MCI at follow-up. METHODS: Framingham Offspring participants underwent brain MRI and neuropsychological assessment at baseline (n=1049) and follow-up (n=561). Participants were classified at baseline and at follow-up as cognitively normal or MCI using sensitive neuropsychological criteria. White matter hyperintensity (WMH) volume, covert brain infarcts, hippocampal volume, and total cerebral brain volume were quantified. RESULTS: Baseline measures of WMH and hippocampal volume were associated with MCI status cross-sectionally and also with conversion from normal cognition to MCI at 6.5-year follow-up. Annualized change rates in total cerebral brain volume and hippocampal volume were associated with conversion from normal cognition to MCI to follow-up. DISCUSSION: Baseline WMH and hippocampal volume are markers that are both associated with conversion from normal cognition to MCI, highlighting the role of both vascular lesions and neurodegeneration in MCI

Efficient Photoionization-Loading of Trapped Cadmium Ions with Ultrafast Pulses

Atomic cadmium ions are loaded into radiofrequency ion traps by photoionization of atoms in a cadmium vapor with ultrafast laser pulses. The photoionization is driven through an intermediate atomic resonance with a frequency-quadrupled mode-locked Ti:Sapphire laser that produces pulses of either 100 fsec or 1 psec duration at a central wavelength of 229 nm. The large bandwidth of the pulses photoionizes all velocity classes of the Cd vapor, resulting in high loading efficiencies compared to previous ion trap loading techniques. Measured loading rates are compared with a simple theoretical model, and we conclude that this technique can potentially ionize every atom traversing the laser beam within the trapping volume. This may allow the operation of ion traps with lower levels of background pressures and less trap electrode surface contamination. The technique and laser system reported here should be applicable to loading most laser-cooled ion species.Comment: 11 pages, 12 figure

Membranous nephropathy in a patient with hereditary angioedema: a case report

<p>Abstract</p> <p>Introduction</p> <p>Hereditary angioedema is the commonest inherited disorder of the complement system and has been associated with several immune glomerular diseases. A case of nephrotic syndrome and renal impairment due to idiopathic membranous glomerulonephritis in a patient with hereditary angioedema has not been described before.</p> <p>Case presentation</p> <p>We present the first reported case of the association of membranous nephropathy and hereditary angioedema in a 43-year-old male Caucasian patient who presented with acute intestinal angioedema, hypertension, acute pancreatitis, renal impairment and generalised body swelling due to severe nephrotic syndrome. We present the challenges involved in the clinical management of the patient.</p> <p>Conclusion</p> <p>This patient's presentation with severe nephrotic syndrome, renal impairment and hypertension required aggressive treatment of the membranous nephropathy given the high risk for progression to end stage renal failure. The contraindication to angiotensin converting enzyme inhibitors and angiotensin II receptor blockers in this patient, the lack of published evidence on the use of alkylating agents and other immunosuppressive agents in patients with hereditary angioedema and the lack of published data on the management of similar cases presented a clinical challenge in this patient's management.</p

Precautionary Regulation in Europe and the United States: A Quantitative Comparison

Much attention has been addressed to the question of whether Europe or the United States adopts a more precautionary stance to the regulation of potential environmental, health, and safety risks. Some commentators suggest that Europe is more risk-averse and precautionary, whereas the US is seen as more risk-taking and optimistic about the prospects for new technology. Others suggest that the US is more precautionary because its regulatory process is more legalistic and adversarial, while Europe is more lax and corporatist in its regulations. The flip-flop hypothesis claims that the US was more precautionary than Europe in the 1970s and early 1980s, and that Europe has become more precautionary since then. We examine the levels and trends in regulation of environmental, health, and safety risks since 1970. Unlike previous research, which has studied only a small set of prominent cases selected non-randomly, we develop a comprehensive list of almost 3,000 risks and code the relative stringency of regulation in Europe and the US for each of 100 risks randomly selected from that list for each year from 1970 through 2004. Our results suggest that: (a) averaging over risks, there is no significant difference in relative precaution over the period, (b) weakly consistent with the flip-flop hypothesis, there is some evidence of a modest shift toward greater relative precaution of European regulation since about 1990, although (c) there is a diversity of trends across risks, of which the most common is no change in relative precaution (including cases where Europe and the US are equally precautionary and where Europe or the US has been consistently more precautionary). The overall finding is of a mixed and diverse pattern of relative transatlantic precaution over the period