Curl up with a good B\mathbf B: Detecting ultralight dark matter with differential magnetometry

Ultralight dark matter (such as kinetically mixed dark-photon dark matter or axionlike dark matter) can source an oscillating magnetic-field signal at the Earth's surface, which can be measured by a synchronized array of ground-based magnetometers. The global signal of ultralight dark matter can be robustly predicted for low masses, when the wavelength of the dark matter is larger than the radius of the Earth, $\lambda_\mathrm{DM}\gg R$. However, at higher masses, environmental effects, such as the Schumann resonances, can become relevant, making the global magnetic-field signal $\mathbf B$ difficult to reliably model. In this work, we show that $\nabla\times\mathbf B$ is robust to global environmental details, and instead only depends on the local dark matter amplitude. We therefore propose to measure the local curl of the magnetic field at the Earth's surface, as a means for detecting ultralight dark matter with $\lambda_\mathrm{DM}\lesssim R$. As this measurement requires vertical gradients, it can be done near a hill/mountain. Our measurement scheme not only allows for a robust prediction, but also acts as a background rejection scheme for external noise sources. We show that our technique can be the most sensitive terrestrial probe of dark-photon dark matter for frequencies $10\,\mathrm{Hz}\leq f_{A'}\leq1\,\mathrm{kHz}$ (corresponding to masses $4\times10^{-14}\,\mathrm{eV}\leq m_{A'}\leq4\times10^{-12}\,\mathrm{eV}$). It can also achieve sensitivities to axionlike dark matter comparabe to the CAST helioscope, in the same frequency range.Comment: 16 pages, 3 figure

A General Isotherm Equation for a Monovalent Ionic Crystal Containing Impurity in +n Valency State

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Molecular Simulation of MoS2 Exfoliation.

A wide variety of two-dimensional layered materials are synthesized by liquid-phase exfoliation. Here we examine exfoliation of MoS2 into nanosheets in a mixture of water and isopropanol (IPA) containing cavitation bubbles. Using force fields optimized with experimental data on interfacial energies between MoS2 and the solvent, multimillion-atom molecular dynamics simulations are performed in conjunction with experiments to examine shock-induced collapse of cavitation bubbles and the resulting exfoliation of MoS2. The collapse of cavitation bubbles generates high-speed nanojets and shock waves in the solvent. Large shear stresses due to the nanojet impact on MoS2 surfaces initiate exfoliation, and shock waves reflected from MoS2 surfaces enhance exfoliation. Structural correlations in the solvent indicate that shock induces an ice VII like motif in the first solvation shell of water

Teaching computer programming with PRIMM: a sociocultural perspective

Background and Context: With computing now becoming a mandatory subject in school in many countries, there is a need for clearly defined pedagogical strategies to support all learners; this is particularly pertinent when teaching computer programming, which novice adults have struggled with for decades. Vygotsky’s sociocultural theory emphasises the importance of language, mediation, and the transfer of skills and knowledge from the social into the cognitive plane. This perspective has influenced the development of PRIMM (Predict, Run, Investigate, Modify, Make), a structured approach to teaching programming. Objective: The objective of the study was to find out if using PRIMM to teach programming had an impact on learner attainment in secondary school, and the extent to which it was a valuable method for teachers. Method: We evaluated the use of PRIMM in 13 schools with 493 students aged 11-14 alongside a control group, using a mixed-methods approach. Teachers delivered programming lessons using the PRIMM approach for 8-12 weeks. Data were collected via a combination of a baseline test, a post-test to compare control and experimental groups, and teacher interviews. Findings: Learners who participated in the PRIMM lessons performed better in the post test than the control group. Teachers reported several benefits of the PRIMM approach, including that PRIMM helped them to teach effectively in mixed-ability classes, enabling all learners to make progress. Implications: We hope that PRIMM makes a contribution to programming education research, as it builds on previous work in effective pedagogy for teachers, and encourages the use of language and dialogue to facilitate understanding. Through our evaluation of PRIMM and engagement with classroom teachers, we propose a framework for understanding the learning of programming in the classroom, and present this as an avenue for further research

Protocol for a randomised controlled trial investigating the effectiveness of an online e health application for the prevention of Generalised Anxiety Disorder

BACKGROUND Generalised Anxiety Disorder (GAD) is a highly prevalent psychiatric disorder. Effective prevention in young adulthood has the potential to reduce the prevalence of the disorder, to reduce disability and lower the costs of the disorder to the community. The present trial (the WebGAD trial) aims to evaluate the effectiveness of an evidence-based online prevention website for GAD. METHODS/DESIGN The principal clinical question under investigation is the effectiveness of an online GAD intervention (E-couch) using a community-based sample. We examine whether the effect of the intervention can be maximised by either human support, in the form of telephone calls, or by automated support through emails. The primary outcome will be a reduction in symptoms on the GAD-7 in the active arms relative to the non active intervention arms. DISCUSSION The WebGAD trial will be the first to evaluate the use of an internet-based cognitive behavioural therapy (CBT) program contrasted with a credible control condition for the prevention of GAD and the first formal RCT evaluation of a web-based program for GAD using community recruitment. In general, internet-based CBT programs have been shown to be effective for the treatment of other anxiety disorders such as Post Traumatic Stress Disorder, Social Phobia, Panic Disorder and stress in clinical trials; however there is no evidence for the use of internet CBT in the prevention of GAD. Given the severe shortage of therapists identified in Australia and overseas, and the low rates of treatment seeking in those with a mental illness, the successful implementation of this protocol has important practical outcomes. If found to be effective, WebGAD will provide those experiencing GAD with an easily accessible, free, evidence-based prevention tool which can be promoted and disseminated immediately

Structural basis of mitochondrial receptor binding and constriction by DRP1.

Mitochondrial inheritance, genome maintenance and metabolic adaptation depend on organelle fission by dynamin-related protein 1 (DRP1) and its mitochondrial receptors. DRP1 receptors include the paralogues mitochondrial dynamics proteins of 49 and 51 kDa (MID49 and MID51) and mitochondrial fission factor (MFF); however, the mechanisms by which these proteins recruit and regulate DRP1 are unknown. Here we present a cryo-electron microscopy structure of full-length human DRP1 co-assembled with MID49 and an analysis of structure- and disease-based mutations. We report that GTP induces a marked elongation and rotation of the GTPase domain, bundle-signalling element and connecting hinge loops of DRP1. In this conformation, a network of multivalent interactions promotes the polymerization of a linear DRP1 filament with MID49 or MID51. After co-assembly, GTP hydrolysis and exchange lead to MID receptor dissociation, filament shortening and curling of DRP1 oligomers into constricted and closed rings. Together, these views of full-length, receptor- and nucleotide-bound conformations reveal how DRP1 performs mechanical work through nucleotide-driven allostery

Ubiquitinylation of α-Synuclein by Carboxyl Terminus Hsp70-Interacting Protein (CHIP) Is Regulated by Bcl-2-Associated Athanogene 5 (BAG5)

Parkinson's disease (PD) is a common neurodegenerative condition in which abnormalities in protein homeostasis, or proteostasis, may lead to accumulation of the protein α-synuclein (α-syn). Mutations within or multiplications of the gene encoding α-syn are known to cause genetic forms of PD and polymorphisms in the gene are recently established risk factors for idiopathic PD. α-syn is a major component of Lewy bodies, the intracellular proteinaceous inclusions which are pathological hallmarks of most forms of PD. Recent evidence demonstrates that α-syn can self associate into soluble oligomeric species and implicates these α-syn oligomers in cell death. We have previously shown that carboxyl terminus of Hsp70-interacting protein (CHIP), a co-chaperone molecule with E3 ubiquitin ligase activity, may reduce the levels of toxic α-syn oligomers. Here we demonstrate that α-syn is ubiquitinylated by CHIP both in vitro and in cells. We find that the products from ubiquitinylation by CHIP include both monoubiquitinylated and polyubiquitinylated forms of α-syn. We also demonstrate that CHIP and α-syn exist within a protein complex with the co-chaperone bcl-2-associated athanogene 5 (BAG5) in brain. The interaction of CHIP with BAG5 is mediated by Hsp70 which binds to the tetratricopeptide repeat domain of CHIP and the BAG domains of BAG5. The Hsp70-mediated association of BAG5 with CHIP results in inhibition of CHIP E3 ubiquitin ligase activity and subsequently reduces α-syn ubiquitinylation. Furthermore, we use a luciferase-based protein-fragment complementation assay of α-syn oligomerization to investigate regulation of α-syn oligomers by CHIP in living cells. We demonstrate that BAG5 mitigates the ability of CHIP to reduce α-syn oligomerization and that non-ubiquitinylated α-syn has an increased propensity for oligomerization. Thus, our results identify CHIP as an E3 ubiquitin ligase of α-syn and suggest a novel function for BAG5 as a modulator of CHIP E3 ubiquitin ligase activity with implications for CHIP-mediated regulation of α-syn oligomerization

Molecular Dipolar Crystals as High Fidelity Quantum Memory for Hybrid Quantum Computing

We study collective excitations of rotational and spin states of an ensemble of polar molecules, which are prepared in a dipolar crystalline phase, as a candidate for a high fidelity quantum memory. While dipolar crystals are formed in the high density limit of cold clouds of polar molecules under 1D and 2D trapping conditions, the crystalline structure protects the molecular qubits from detrimental effects of short range collisions. We calculate the lifetime of the quantum memory by identifying the dominant decoherence mechanisms, and estimate their effects on gate operations, when a molecular ensemble qubit is transferred to a superconducting strip line cavity (circuit QED). In the case rotational excitations coupled by dipole-dipole interactions we identify phonons as the main limitation of the life time of qubits. We study specific setups and conditions, where the coupling to the phonon modes is minimized. Detailed results are presented for a 1D dipolar chain

A prospective comparative study of outcome between open lichtenstein versus laparoscopic repair of inguinal hernia

Background: Laparoscopic hernia repair is technically difficult and has long learning curve than open repair. Moreover, with increased cost of procedure do patient really get benefited in terms of intraoperative time duration, post-operative pain and complications, length of hospital stays, and time taken to return to usual activity needs to be studied.Methods: In this prospective observational study of 100 patients including unilateral, bilateral, direct and indirect inguinal hernia and excluding obstructed and strangulated hernia, 61 patients underwent open repair and 39 patients underwent laparoscopic hernia repair. Pain analysis was done with visual analogue scale. Unpaired student T test and Chi square test used (p<0.05).Results: Baseline characteristics age, sex of the two groups were similar. Mean operative time in laparoscopic group was 105.38±35.13 minutes and in open group was 79.95±31.12 minutes (p<0.001). There was statistically significant difference in mean pain score of laproscopic verses open techniques (p<0.001). Urinary retention was the most common post-operative complication in both groups but was statistically not significant. Mean hospital stay in laparoscopic group was 1.56±0.50 days and in open group was 1.9±0.50 days (p-0.002). Mean time taken to return to usual activity in open repair was 41.10±27.15 days and in laparoscopic group was 16.23±6.37 days (p-0.001).Conclusions: This study showed that in laparoscopic repair of inguinal hernia patients have less post-operative pain, shorter hospital stays and early return to work. However, the laparoscopic technique had longer operative time duration