Fast Sensing of Double-Dot Charge Arrangement and Spin State with a Radio-Frequency Sensor Quantum Dot

Single-shot measurement of the charge arrangement and spin state of a double quantum dot are reported with measurement times down to 100 ns. Sensing uses radio-frequency reflectometry of a proximal quantum dot in the Coulomb blockade regime. The sensor quantum dot is up to 30 times more sensitive than a comparable quantum point-contact sensor and yields three times greater signal to noise in rf single-shot measurements. Numerical modeling is qualitatively consistent with experiment and shows that the improved sensitivity of the sensor quantum dot results from reduced lifetime broadening and screening.PhysicsOther Research Uni

Epidermal growth factor targeting of bacteriophage to the choroid plexus for gene delivery to the central nervous system via cerebrospinal fluid

Because the choroid plexus normally controls the production and composition of cerebrospinal fluid and, as such, its many functions of the central nervous system, we investigated whether ligand-mediated targeting could deliver genes to its secretory epithelium. We show here that when bacteriophages are targeted with epidermal growth factor, they acquire the ability to enter choroid epithelial cells grown in vitro as cell cultures, ex vivo as tissue explants or in vivo by intracerebroventricular injection. The binding and internalization of these particles activate EGF receptors on targeted cells, and the dose- and time-dependent internalization of particles is inhibited by the presence of excess ligand. When the phage genome is further reengineered to contain like green fluorescent protein or firefly luciferase under control of the cytomegalovirus promoter, gene expression is detectable in the choroid plexus and ependymal epithelium by immunohistochemistry or by noninvasive imaging, respectively. Taken together, these data support the hypothesis that reengineered ligand-mediated gene delivery should be considered a viable strategy to increase the specificity of gene delivery to the central nervous system and bypass the blood-brain barrier so as to exploit the biological effectiveness of the choroid plexus as a portal of entry into the brain

Persecutory delusions: Effects of cognitive bias modification for interpretation and the Maudsley Review Training Programme on social anxiety, jumping to conclusions, belief inflexibility and paranoia

Background and objectives: The Threat Anticipation Model (Freeman, 2007) implicates social anxiety, jumping to conclusions (JTC) and belief inflexibility in persecutory delusions. We investigated whether Cognitive Bias Modification for Interpretation (CBM-I; Turner et al., 2011) improves social anxiety by targeting negative interpretation bias of ambiguous social information. We determined whether the Maudsley Review Training Programme (MRTP; Waller et al., 2011) improves JTC, belief inflexibility and paranoia. We also explored effects of CBM-I on JTC/belief inflexibility and paranoia, as well as the MRTP on social anxiety. Methods: Twelve participants from Early Intervention and Recovery Services in East Anglia completed measures of social anxiety, paranoia, JTC and belief inflexibility. A concurrent multiple baseline case series design was used. Results: Three of twelve participants improved in social anxiety following CBM-I, paranoia improved in 6/12 cases. CBM-I had no effect on JTC/belief inflexibility. The MRTP improved JTC and/or belief inflexibility in 9/12 cases, while improving paranoia for 6/12 individuals. The MRTP improved social anxiety in one case. Limitations: The small sample size and large effects necessary for single case series designs limit the generality of findings. These are discussed in more detail. Conclusions: This study suggests that whilst both CBM-I and the MRTP may have a positive impact on paranoia and social anxiety, the effects on JTC/belief inflexibility are largely specific to the MRTP. Relationships between social anxiety, JTC, belief inflexibility and paranoia existed in 10/12 individuals, supporting the Threat Anticipation Model

Self-concept clarity and compulsive Internet use: The role of preference for virtual interactions and employment status in British and North-American samples

Background and aims: Compulsive Internet Use (CIU) describes a maladaptive relationship with the Internet characterised by loss of control and conflict. Although also affecting adults, most studies use teenage samples, and theoretical development on risk factors is scarce. According to Davis (2001), the social connectivity function of the Internet is key in identifying traits associated with CIU. Since Self-Concept Clarity (SCC) is strongly related to social anxiety, and virtual interactions allow “self-edition”, we hypothesized that individuals low in SCC could choose virtual interactions as safer alternative to satisfy their social needs. This could in turn increase the risk of CIU. Building on a previous study, we also expected CIU to be more harmful in the unemployed. Methods: We collected samples from the UK (N=532) and US (N=502) with equal distribution of employed and unemployed individuals. We ran Measurement Invariance tests to confirm that the constructs were equivalent across countries. Subsequently, we conducted mediation and moderation analysis to test our hypothesis with Multigroup Confirmatory Factor Analysis. Results: Measurement Invariance was confirmed. The relationship between SCC and CIU was partially mediated by preference of virtual interactions in both countries. This preference was significantly related to lower social support. Short term unemployment seemed to accentuate the negative impact of CIU on life satisfaction in both countries, although only marginally significantly in the US. The unemployed reported significantly lower levels of life satisfaction. Conclusion: We demonstrated that SCC is a key vulnerability factor to CIU in adults, and confirmed the additional risks for the unemployed

Supernova Model Discrimination with Hyper-Kamiokande

Core-collapse supernovae are among the most magnificent events in the observable universe. They produce many of the chemical elements necessary for life to exist and their remnants—neutron stars and black holes—are interesting astrophysical objects in their own right. However, despite millennia of observations and almost a century of astrophysical study, the explosion mechanism of core-collapse supernovae is not yet well understood. Hyper-Kamiokande is a next-generation neutrino detector that will be able to observe the neutrino flux from the next galactic core-collapse supernova in unprecedented detail. We focus on the first 500 ms of the neutrino burst, corresponding to the accretion phase, and use a newly-developed, high-precision supernova event generator to simulate Hyper-Kamiokande's response to five different supernova models. We show that Hyper-Kamiokande will be able to distinguish between these models with high accuracy for a supernova at a distance of up to 100 kpc. Once the next galactic supernova happens, this ability will be a powerful tool for guiding simulations toward a precise reproduction of the explosion mechanism observed in nature