Distinct Quantum States Can Be Compatible with a Single State of Reality

Perhaps the quantum state represents information about reality, and not reality directly. Wave function collapse is then possibly no more mysterious than a Bayesian update of a probability distribution given new data. We consider models for quantum systems with measurement outcomes determined by an underlying physical state of the system but where several quantum states are consistent with a single underlying state---i.e., probability distributions for distinct quantum states overlap. Significantly, we demonstrate by example that additional assumptions are always necessary to rule out such a model.Comment: 5 pages, 2 figure

Genotyping of Entamoeba species in South Africa: diversity, stability, and transmission patterns within families.

Using a recently described polymerase chain reaction-based DNA typing method for Entamoeba histolytica and E. dispar, we investigated the genetic diversity of these species in a geographically restricted region of South Africa. Patterns were stable over time in the same infection, and, with few exceptions, infected family members carried the same strain. However, both species exhibited remarkable variation, with no 2 family groups being infected with the same strain of E. histolytica. Mixed infections were rare. The results indicate that this typing method will be useful in identifying epidemiological linkage between infections

Manipulating etch selectivities in XeF2 vapour etching

The vapour etching of silicon sacrificial layers is often a critical process in the fabrication of micro/nanosystems. This method has a number of attractive features, in particular, high etch rates of sacrificial silicon layers and good selectivities associated with photoresist, SiO₂, stoichiometric Si₃N₄ and a number of regularly used metal films. However, materials that are commonly inert to XeF₂ are etched when located in the proximity of a silicon sacrificial layer. This proximity is a common situation in the fabrication of such systems and can become a critical issue affecting process control and device reliability. This work uses test structures that have been designed to be very sensitive, thereby delivering much lower selectivities then are typically reported in the literature. This sensitive quantification of the proximity effect is used to evaluate methods designed to improve the selectivity. This work suggests that a reduction in the processing temperature from 25°C to 10°C increases the Si: PECVD SiN selectivity by 68%. However, a more easily implemented modification is to flow hydrogen into the reaction chamber. This method improves the Si: PECVD SiN selectivity by an order of magnitude and the Si: LPCVD SiN selectivity between 200% and 600%. [2020-0346]

Controlled Cooperative Wetting Enabled Heterogeneous Structured 3D Morphing Transducers

A unique microfluidics approach for functional hydrogel patterning with multilayered heterogeneous structures is presented. Prepolymer solution droplets with differentiated sodium acrylate concentrations are dispensed/printed in a wetting‐controlled “two‐parallel plate” (TPP, like a Hele‐Shaw Cell) system. The gelation within the system enables hydrogel bilayer structures with reconfigurable 3D deformations driven by in‐plane and through‐thickness heterogeneity under stimuli‐responsive mask‐less swelling/deswelling. The cooperation between swelling mismatch of functional groups results in a higher complexity of 3D reconfiguration in responding to discrete levels of stimulation inputs. This facile patterning technology with an in‐built ionic hierarchy can be scaled up/down with advanced transducing functionalities in various fields

Synthesis and Stereochemical Assignment of (+)-Chamuvarinin

Supported by grants from EPSRC (EP/F011458/1) and The Wellcome Trust (086658).A stereocontrolled total synthesis of (+)-chamuvarinin, isolated from the root extract of Uvaria Chamae, utilizes a convergent modular strategy to construct the adjacently linked C15−C28 ether array, followed by a late-stage Julia−Kocienski olefination to append the butenolide motif. This constitutes the first total synthesis of (+)-chamuvarinin, defining the relative and absolute configuration of this unique annonaceous acetogenin.Publisher PDFPeer reviewe

A candidate gene analysis and GWAS for genes associated with maternal nondisjunction of chromosome 21

Human nondisjunction errors in oocytes are the leading cause of pregnancy loss, and for pregnancies that continue to term, the leading cause of intellectual disabilities and birth defects. For the first time, we have conducted a candidate gene and genome-wide association study to identify genes associated with maternal nondisjunction of chromosome 21 as a first step to understand predisposing factors. A total of 2,186 study participants were genotyped on the HumanOmniExpressExome-8v1-2 array. These participants included 749 live birth offspring with standard trisomy 21 and 1,437 parents. Genotypes from the parents and child were then used to identify mothers with nondisjunction errors derived in the oocyte and to establish the type of error (meiosis I or meiosis II). We performed a unique set of subgroup comparisons designed to leverage our previous work suggesting that the etiologies of meiosis I and meiosis II nondisjunction differ for trisomy 21. For the candidate gene analysis, we selected genes associated with chromosome dynamics early in meiosis and genes associated with human global recombination counts. Several candidate genes showed strong associations with maternal nondisjunction of chromosome 21, demonstrating that genetic variants associated with normal variation in meiotic processes can be risk factors for nondisjunction. The genome-wide analysis also suggested several new potentially associated loci, although follow-up studies using independent samples are required