Health literacy of an urban business community.

The impact of community-based organizations on the delivery of health care knowledge is well documented. Little research has focused on the importance of health literacy in the dissemination of health care information by minority small business owners. This study sampled 38 business owners within a local business district to assess their level of health literacy. Although adequate health literacy is not required to serve as a community resource, it may be necessary to understand the health literacy level of local business owners as gatekeepers in order to develop appropriate training/educational programs. The results of this descriptive cross-sectional study indicate that for sample of business owners, health literacy levels are adequate. The findings suggest the feasibility of using local business owners as disseminators of health-related materials to the communities in which they operate their businesses.

Rare structural variation of synapse and neurotransmission genes in autism.

Autism spectrum disorders (ASDs) comprise a constellation of highly heritable neuropsychiatric disorders. Genome-wide studies of autistic individuals have implicated numerous minor risk alleles but few common variants, suggesting a complex genetic model with many contributing loci. To assess commonality of biological function among rare risk alleles, we compared functional knowledge of genes overlapping inherited structural variants in idiopathic ASD subjects relative to healthy controls. In this study we show that biological processes associated with synapse function and neurotransmission are significantly enriched, with replication, in ASD subjects versus controls. Analysis of phenotypes observed for mouse models of copy-variant genes established significant and replicated enrichment of observable phenotypes consistent with ASD behaviors. Most functional terms retained significance after excluding previously reported ASD loci. These results implicate several new variants that involve synaptic function and glutamatergic signaling processes as important contributors of ASD pathophysiology and suggest a sizable pool of additional potential ASD risk loci.

Next-generation sequencing: the solution for high-resolution, unambiguous human leukocyte antigen typing.

Human leukocyte antigen (HLA) typing has been a challenge for more than 50 years. Current methods (Sanger sequencing, sequence-specific primers [SSP], sequence-specific oligonucleotide probes [SSOP]) continue to generate ambiguities that are time-consuming and expensive to resolve. However, next-generation sequencing (NGS) overcomes ambiguity through the combination of clonal amplification, which provides on-phase sequence and a high level of parallelism, whereby millions of sequencing reads are produced enabling an expansion of the HLA regions sequenced. We explored HLA typing using NGS through a three-step process. First, HLA-A, -B, -C, -DRB1, and -DQB1 were amplified with long-range PCR. Subsequently, amplicons were sequenced using the 454 GS-FLX platform. Finally, sequencing data were analyzed with Assign-NG software. In a single experiment, four individual samples and two mixtures were sequenced producing >75 Mb of sequence from >300,000 individual sequence reads (average length, 244 b). The reads were aligned and covered 100% of the regions amplified. Allele assignment was 100% concordant with the known HLA alleles of our samples. Our results suggest this method can be a useful tool for complete genomic characterization of new HLA alleles and for completion of sequence for existing, partially sequenced alleles. NGS can provide complete, unambiguous, high-resolution HLA typing; however, further evaluation is needed to explore the feasibility of its routine use.

Rare structural variants found in attention-deficit hyperactivity disorder are preferentially associated with neurodevelopmental genes.

Attention-deficit/hyperactivity disorder (ADHD) is a common and highly heritable disorder, but specific genetic factors underlying risk remain elusive. To assess the role of structural variation in ADHD, we identified 222 inherited copy number variations (CNVs) within 335 ADHD patients and their parents that were not detected in 2026 unrelated healthy individuals. Although no excess CNVs, either deletions or duplications, were found in the ADHD cohort relative to controls, the inherited rare CNV-associated gene set was significantly enriched for genes reported as candidates in studies of autism, schizophrenia and Tourette syndrome, including A2BP1, AUTS2, CNTNAP2 and IMMP2L. The ADHD CNV gene set was also significantly enriched for genes known to be important for psychological and neurological functions, including learning, behavior, synaptic transmission and central nervous system development. Four independent deletions were located within the protein tyrosine phosphatase gene, PTPRD, recently implicated as a candidate gene for restless legs syndrome, which frequently presents with ADHD. A deletion within the glutamate receptor gene, GRM5, was found in an affected parent and all three affected offspring whose ADHD phenotypes closely resembled those of the GRM5 null mouse. Together, these results suggest that rare inherited structural variations play an important role in ADHD development and indicate a set of putative candidate genes for further study in the etiology of ADHD.

High-order quantum resonances observed in a periodically kicked Bose-Einstein condensate.

We have observed high-order quantum resonances in a realization of the quantum delta-kicked rotor, using Bose-condensed Na atoms subjected to a pulsed standing wave of laser light. These resonances occur for pulse intervals that are rational fractions of the Talbot time, and are characterized by ballistic momentum transfer to the atoms. The condensate's narrow momentum distribution not only permits the observation of the quantum resonances at 3/4 and 1/3 of the Talbot time, but also allows us to study scaling laws for the resonance width in quasimomentum and pulse interval.

Quantum accelerator modes from the Farey tree.

We show that mode locking finds a purely quantum nondissipative counterpart in atom-optical quantum accelerator modes. These modes are formed by exposing cold atoms to periodic kicks in the direction of the gravitational field. They are anchored to generalized Arnol'd tongues, parameter regions where driven nonlinear classical systems exhibit mode locking. A hierarchy for the rational numbers known as the Farey tree provides an ordering of the Arnol'd tongues and hence of experimentally observed accelerator modes.

Gravity-sensitive quantum dynamics in cold atoms.

We subject a falling cloud of cold cesium atoms to periodic kicks from a sinusoidal potential created by a vertical standing wave of laser light. By controllably accelerating the potential, we show quantum accelerator mode dynamics to be highly sensitive to the effective gravitational acceleration when close to specific, resonant values. This quantum sensitivity to a control parameter is reminiscent of that associated with classical chaos and promises techniques for precision measurement.

Experimental observation of high-order quantum accelerator modes.

Using a freely falling cloud of cold cesium atoms periodically kicked by pulses from a vertical standing wave of laser light, we present the first experimental observation of high-order quantum accelerator modes. This confirms the recent prediction by Fishman, Guarneri, and Rebuzzini [Phys. Rev. Lett. 89, 084101 (2002)]]. We also show how these accelerator modes can be identified with the stable regions of phase space in a classical-like chaotic system, despite their intrinsically quantum origin.

Signatures of quantum stability in a classically chaotic system.

We experimentally and numerically investigate the quantum accelerator mode dynamics of an atom optical realization of the quantum delta-kicked accelerator, whose classical dynamics are chaotic. Using a Ramsey-type experiment, we observe interference, demonstrating that quantum accelerator modes are formed coherently. We construct a link between the behavior of the evolution's fidelity and the phase space structure of a recently proposed pseudoclassical map, and thus account for the observed interference visibilities.

Approaching classicality in quantum accelerator modes through decoherence.

We describe measurements of the mean energy of an ensemble of laser-cooled atoms in an atom optical system in which the cold atoms, falling freely under gravity, receive approximate delta-kicks from a pulsed standing wave of laser light. We call this system a "delta-kicked accelerator." Additionally, we can counteract the effect of gravity by appropriate shifting of the position of the standing wave, which restores the dynamics of the standard delta-kicked rotor. The presence of gravity (delta-kicked accelerator) yields quantum phenomena, quantum accelerator modes, which are markedly different from those in the case for which gravity is absent (delta-kicked rotor). Quantum accelerator modes result in a much higher rate of increase in the mean energy of the system than is found in its classical analog. When gravity is counteracted, the system exhibits the suppression of the momentum diffusion characteristic of dynamical localization. The effect of noise is examined and a comparison is made with simulations of both quantum-mechanical and classical versions of the system. We find that the introduction of noise results in the restoration of several signatures of classical behavior, although significant quantum features remain.

Quantum enhancement of momentum diffusion in the delta-kicked rotor.

We present detailed observations of the quantum delta-kicked rotor in the vicinity of a quantum resonance. Our experiment consists of an ensemble of cold cesium atoms subject to a pulsed off-resonant standing wave of light. We measure the mean energy and show clearly that at the quantum resonance it is a local maximum. We also examine the effect of noise on the system and find that the greatest sensitivity to this occurs at the resonances. This makes these regions ideal for examining quantum-classical correspondence. A picture based on diffraction is developed which allows the experiments to be readily understood.