Double Disadvantage in the Process of Disablement: Race as a Moderator in the Association Between Chronic Conditions and Functional Limitations.

OBJECTIVES: This study evaluated (a) whether the association between chronic conditions and functional limitations vary by race/ethnicity, and (b) whether socioeconomic status accounted for any observed racial variation in the association between chronic conditions and functional limitations. METHOD: The Health and Retirement Study data were used to assess whether race/ethnicity moderated the association between chronic conditions and functional limitations, and whether education, income, and/or wealth mediated any of the observed moderation by race/ethnicity. RESULTS: Results from structural equation models of latent growth curves with random onset indicated that (a) the positive association between chronic conditions and functional limitations onset was larger for African Americans and Hispanics than it was for Whites, but (b) this difference largely persisted net of socioeconomic status. DISCUSSION: African Americans and Hispanics endure a multiplicative double disadvantage in the early stages of the disablement process where they experience (a) a more rapid onset and higher levels of functional limitations, and (b) greater risk of functional limitation onset associated with chronic conditions compared to their White counterparts. Moreover, basic economic policies are unlikely to curtail the greater risk of functional limitations onset associated with chronic conditions encountered by African Americans and Hispanics.

Macroscopic Singlet-Triplet Qubit in Synthetic Spin-One Chain in Semiconductor Nanowires.

We show here how to create macroscopic quantum states in a semiconductor device: a chain of InAs quantum dots embedded in an InP nanowire. Filling the nanowire with 4 electrons per dot creates a synthetic spin-one chain, with four-fold degenerate topological ground state protected by a Haldane gap. The four states correspond to two spin-½ quasiparticles localised at the ends of the macroscopic wire. The quasiparticle spins are mapped onto a robust, macroscopic, singlet-triplet qubit. These predictions are supported by a microscopic theory and extensive numerical simulations.

Graphene neural interfaces for artifact free optogenetics.

Light-induced artifacts in metal-based microelectrodes significantly limit simultaneous use of electrophysiology with optogenetics or optical imaging. In this work, we systematically investigate light-induced artifacts in Au and transparent graphene electrodes fabricated in the same batch. We demonstrate that the Au electrodes show light artifacts resembling genuine local field potentials, while graphene electrodes are free of light-induced artifacts. With its other desirable properties including high mechanical strength, good conductivity, transparency, and biocompatibility, graphene electrodes show great promise for combining electrical and optical modalities in the same experiment.

A clinic compatible, open source electrophysiology system.

Open source electrophysiology (ephys) recording systems have several advantages over commercial systems such as customization and affordability enabling more researchers to conduct ephys experiments. Notable open source ephys systems include Open-Ephys, NeuroRighter and more recently Willow, all of which have high channel count (64+), scalability, and advanced software to develop on top of. However, little work has been done to build an open source ephys system that is clinic compatible, particularly in the operating room where acute human electrocorticography (ECoG) research is performed. We developed an affordable (<; $10,000) and open system for research purposes that features power isolation for patient safety, compact and water resistant enclosures and 256 recording channels sampled up to 20ksam/sec, 16-bit. The system was validated by recording ECoG with a high density, thin film device for an acute, awake craniotomy study at UC San Diego, Thornton Hospital Operating Room.

Volatile fractionation in the early solar system and chondrule/matrix complementarity.

Bulk chondritic meteorites and terrestrial planets show a monotonic depletion in moderately volatile and volatile elements relative to the Sun's photosphere and CI carbonaceous chondrites. Although volatile depletion was the most fundamental chemical process affecting the inner solar nebula, debate continues as to its cause. Carbonaceous chondrites are the most primitive rocks available to us, and fine-grained, volatile-rich matrix is the most primitive component in these rocks. Several volatile depletion models posit a pristine matrix, with uniform CI-like chemistry across the different chondrite groups. To understand the nature of volatile fractionation, we studied minor and trace element abundances in fine-grained matrices of a variety of carbonaceous chondrites. We find that matrix trace element abundances are characteristic for a given chondrite group; they are depleted relative to CI chondrites, but are enriched relative to bulk compositions of their parent meteorites, particularly in volatile siderophile and chalcophile elements. This enrichment produces a highly nonmonotonic trace element pattern that requires a complementary depletion in chondrule compositions to achieve a monotonic bulk. We infer that carbonaceous chondrite matrices are not pristine: they formed from a material reservoir that was already depleted in volatile and moderately volatile elements. Additional thermal processing occurred during chondrule formation, with exchange of volatile siderophile and chalcophile elements between chondrules and matrix. This chemical complementarity shows that these chondritic components formed in the same nebula region.

Evidence for recycled Archaean oceanic mantle lithosphere in the Azores plume.

The compositional differences between mid-ocean-ridge and ocean-island basalts place important constraints on the form of mantle convection. Also, it is thought that the scale and nature of heterogeneities within plumes and the degree to which heterogeneous material endures within the mantle might be reflected in spatial variations of basalt composition observed at the Earth's surface. Here we report osmium isotope data on lavas from a transect across the Azores archipelago which vary in a symmetrical pattern across what is thought to be a mantle plume. Many of the lavas from the centre of the plume have lower 187Os/188Os ratios than most ocean-island basalts and some extend to subchondritic 187Os/188Os ratios-lower than any yet reported from ocean-island basalts. These low ratios require derivation from a depleted, harzburgitic mantle, consistent with the low-iron signature of the Azores plume. Rhenium-depletion model ages extend to 2.5 Gyr, and we infer that the osmium isotope signature is unlikely to be derived from Iberian subcontinental lithospheric mantle. Instead, we interpret the osmium isotope signature as having a deep origin and infer that it may be recycled, Archaean oceanic mantle lithosphere that has delaminated from its overlying oceanic crust. If correct, our data provide evidence for deep mantle subduction and storage of oceanic mantle lithosphere during the Archaean era.