British Children’s and Adults’ Perceptions of Robots

Robotics and artificial intelligence (AI) systems are quickly becoming a familiar part of different aspects of everyday life. We know very little about how children and adults perceive the abilities of different robots and whether these ascriptions are associated with a willingness to interact with a robot. In the current study, we asked British children aged 4-to-13 years and British adults to complete an online experiment. Participants were asked to describe what a robot looks like, give their preference for various types of robots (a social robot, a machine-like robot and a human-like robot), and whether they were willing to engage in different activities with the different robots. Results showed that younger children (4 to 8 years old) are more willing to engage with robots compared to older children (9 to 13 years) and adults. Specifically, younger children were more likely to see robots as kind compared to older children and adults. Younger children were also more likely to rate the social robot as helpful compared to older children and adults. This is also the first study to examine preferences for robots engaging in religious activities and results show that British adults prefer humans over robots to pray for them but such biases may not be generally applicable to children. These results provide current insight into how children and adults in the United Kingdom accept the presence and function of robots

Mixed brittle and viscous strain localisation in pelagic sediments seaward of the Hikurangi margin, New Zealand

Calcareous‐pelagic input sediments are present at several subduction zones and deform differently to their siliciclastic counterparts. We investigate deformation in calcareous‐pelagic sediments drilled ~20 km seaward of the Hikurangi megathrust toe at Site U1520 during IODP Expeditions 372 and 375. Clusters of normal faults and subhorizontal stylolites in the sediments indicate both brittle faulting and viscous pressure solution operated at 150°C where frictional (possibly seismic) slip likely predominates. Plain Language Summary The type of sediments entering subduction zones will influence the way the plates in the subduction zone slide past one another. We looked at limestones in sediments drilled before they reach the subduction zone and found that because of the pressure they are under, they begin to crack and dissolve at very shallow depths. Most of the dissolution happens on thin layers where it concentrates clay by removing other, more soluble minerals. We compare how much vertical shortening we see in the sediments to a computer model. The model overestimates vertical shortening over the history of the sediment unless either high pressure fluids reduce the pressure felt by the sediments, or dissolution is governed by the largest sediment grains rather than their average size. Dissolving and cracking make the sediments weaker by concentrating soft materials such as clay. When these sediments enter the subduction zone, the two plates might slip past one another more easily on these weak regions, possibly during slow slip events

Energy scalable terahertz-wave parametric oscillator using surface-emitted configuration

We experimentally demonstrated the scalability of the terahertz-wave parametric oscillator by using a pump beam with a wide aperture and a high pulse energy. Terahertz-wave absorption by the LiNbO3 crystal in the oscillator is substantially suppressed by employing a surface-emitting cavity configuration. We also improved the conversion efficiency by increasing the parametric interaction in the noncollinear phase-matching geometry. A pump depletion of 54% and a conversion efficiency of 0.9 × 10-6 are achieved. A maximum terahertz output of 382 nJ/pulse was achieved at 1.46 THz using a 8.0-mm-diameter pump beam with a pulse energy of 465 mJ/pulse

Application of constitutive friction laws to glacier seismicity

While analysis of glacial seismicity continues to be a widely used method for interpreting glacial processes, the underlying mechanics controlling glacial stick-slip seismicity remain speculative. Here, we report on laboratory shear experiments of debris-laden ice slid over a bedrock asperity under carefully controlled conditions. By modifying the elastic loading stiffness, we generated the first laboratory icequakes. Our work represents the first comprehensive lab observations of unstable ice-slip events and replicates several seismological field observations of glacier slip, such as slip velocity, stress drop, and the relationship between stress drop and recurrence interval. We also observe that stick-slips initiate above a critical driving velocity and that stress drop magnitude decreases with further increases in velocity, consistent with friction theory and rock-on-rock friction laboratory experiments. Our results demonstrate that glacier slip behavior can be accurately predicted by the constitutive rate-and-state friction laws that were developed for rock friction

Frictional Behavior of Input Sediments to the Hikurangi Trench, New Zealand

AbstractThe Hikurangi subduction zone hosts shallow slow‐slip events, possibly extending to the seafloor. The mechanisms allowing for this behavior are poorly understood but are likely a function of the frictional properties of the downgoing seafloor sediments. We conducted friction experiments at a large range of effective stresses, temperatures, and velocities on incoming sediment to the Hikurangi subduction zone to explore the possible connection of frictional properties to slow‐slip events. These experiments were conducted on multiple apparatuses, allowing us to access a wider range of deformation conditions than is available on any one machine. We find that the material frictionally weakens and becomes less velocity strengthening with increasing effective stress, whereas temperature has only a small effect on both friction and frictional stability. When driven at the plate convergence rate, the sediment exhibits velocity‐weakening behavior. These results imply that the frictional properties of the sediment package subducting at Hikurangi could promote slow‐slip events at the pressures, temperatures, and strain rates expected along the plate boundary thrust up to 10‐km depth without requiring elevated pore fluid pressures. The transition to velocity‐strengthening behavior at faster slip rates could provide a mechanism for limiting unstable slip to slow‐sliding velocities, rather than accommodating deformation through ordinary earthquakes

Study of the plutino object (208996) 2003 AZ84 from stellar occultations: size, shape and topographic features

We present results derived from four stellar occultations by the plutino object (208996) 2003~AZ$_{84}$, detected at January 8, 2011 (single-chord event), February 3, 2012 (multi-chord), December 2, 2013 (single-chord) and November 15, 2014 (multi-chord). Our observations rule out an oblate spheroid solution for 2003~AZ$_{84}$'s shape. Instead, assuming hydrostatic equilibrium, we find that a Jacobi triaxial solution with semi axes $(470 \pm 20) \times (383 \pm 10) \times (245 \pm 8)$~km % axis ratios $b/a= 0.82 \pm 0.05$ and $c/a= 0.52 \pm 0.02$, can better account for all our occultation observations. Combining these dimensions with the rotation period of the body (6.75~h) and the amplitude of its rotation light curve, we derive a density $\rho=0.87 \pm 0.01$~g~cm$^{-3}$ a geometric albedo $p_V= 0.097 \pm 0.009$. A grazing chord observed during the 2014 occultation reveals a topographic feature along 2003~AZ$_{84}$'s limb, that can be interpreted as an abrupt chasm of width $\sim 23$~km and depth $> 8$~km or a smooth depression of width $\sim 80$~km and depth $\sim 13$~km (or an intermediate feature between those two extremes)

Shear behavior of DFDP-1 borehole samples from the Alpine Fault, New Zealand, under a wide range of experimental conditions

The Alpine Fault is a major plate-boundary fault zone that poses a major seismic hazard in southern New Zealand. The initial stage of the Deep Fault Drilling Project has provided sample material from the major lithological constituents of the Alpine Fault from two pilot boreholes. We use laboratory shearing experiments to show that the friction coefficient µ of fault-related rocks and their precursors varies between 0.38 and 0.80 depending on the lithology, presence of pore fluid, effective normal stress, and temperature. Under conditions appropriate for several kilometers depth on the Alpine Fault (100 MPa, 160 °C, fluid-saturated), a gouge sample located very near to the principal slip zone exhibits µ = 0.67, which is high compared with other major fault zones targeted by scientific drilling, and suggests the capacity for large shear stresses at depth. A consistent observation is that every major lithological unit tested exhibits positive and negative values of friction velocity dependence. Critical nucleation patch lengths estimated using representative values of the friction velocity-dependent parameter a−b and the critical slip distance D c , combined with previously documented elastic properties of the wall rock, may be as low as ~3 m. This small value, consistent with a seismic moment M o = ~4 × 1010 for an M w = ~1 earthquake, suggests that events of this size or larger are expected to occur as ordinary earthquakes and that slow or transient slip events are unlikely in the approximate depth range of 3–7 km

Brain structural covariance networks in obsessive-compulsive disorder: a graph analysis from the ENIGMA Consortium.

Brain structural covariance networks reflect covariation in morphology of different brain areas and are thought to reflect common trajectories in brain development and maturation. Large-scale investigation of structural covariance networks in obsessive-compulsive disorder (OCD) may provide clues to the pathophysiology of this neurodevelopmental disorder. Using T1-weighted MRI scans acquired from 1616 individuals with OCD and 1463 healthy controls across 37 datasets participating in the ENIGMA-OCD Working Group, we calculated intra-individual brain structural covariance networks (using the bilaterally-averaged values of 33 cortical surface areas, 33 cortical thickness values, and six subcortical volumes), in which edge weights were proportional to the similarity between two brain morphological features in terms of deviation from healthy controls (i.e. z-score transformed). Global networks were characterized using measures of network segregation (clustering and modularity), network integration (global efficiency), and their balance (small-worldness), and their community membership was assessed. Hub profiling of regional networks was undertaken using measures of betweenness, closeness, and eigenvector centrality. Individually calculated network measures were integrated across the 37 datasets using a meta-analytical approach. These network measures were summated across the network density range of K = 0.10-0.25 per participant, and were integrated across the 37 datasets using a meta-analytical approach. Compared with healthy controls, at a global level, the structural covariance networks of OCD showed lower clustering (P < 0.0001), lower modularity (P < 0.0001), and lower small-worldness (P = 0.017). Detection of community membership emphasized lower network segregation in OCD compared to healthy controls. At the regional level, there were lower (rank-transformed) centrality values in OCD for volume of caudate nucleus and thalamus, and surface area of paracentral cortex, indicative of altered distribution of brain hubs. Centrality of cingulate and orbito-frontal as well as other brain areas was associated with OCD illness duration, suggesting greater involvement of these brain areas with illness chronicity. In summary, the findings of this study, the largest brain structural covariance study of OCD to date, point to a less segregated organization of structural covariance networks in OCD, and reorganization of brain hubs. The segregation findings suggest a possible signature of altered brain morphometry in OCD, while the hub findings point to OCD-related alterations in trajectories of brain development and maturation, particularly in cingulate and orbitofrontal regions

Genome-Wide Association Study and Gene Expression Analysis Identifies CD84 as a Predictor of Response to Etanercept Therapy in Rheumatoid Arthritis

Anti-tumor necrosis factor alpha (anti-TNF) biologic therapy is a widely used treatment for rheumatoid arthritis (RA). It is unknown why some RA patients fail to respond adequately to anti-TNF therapy, which limits the development of clinical biomarkers to predict response or new drugs to target refractory cases. To understand the biological basis of response to anti-TNF therapy, we conducted a genome-wide association study (GWAS) meta-analysis of more than 2 million common variants in 2,706 RA patients from 13 different collections. Patients were treated with one of three anti-TNF medications: etanercept (n = 733), infliximab (n = 894), or adalimumab (n = 1,071). We identified a SNP (rs6427528) at the 1q23 locus that was associated with change in disease activity score (ΔDAS) in the etanercept subset of patients (P = 8×10-8), but not in the infliximab or adalimumab subsets (P>0.05). The SNP is predicted to disrupt transcription factor binding site motifs in the 3′ UTR of an immune-related gene, CD84, and the allele associated with better response to etanercept was associated with higher CD84 gene expression in peripheral blood mononuclear cells (P = 1×10-11 in 228 non-RA patients and P = 0.004 in 132 RA patients). Consistent with the genetic findings, higher CD84 gene expression correlated with lower cross-sectional DAS (P = 0.02, n = 210) and showed a non-significant trend for better ΔDAS in a subset of RA patients with gene expression data (n = 31, etanercept-treated). A small, multi-ethnic replication showed a non-significant trend towards an association among etanercept-treated RA patients of Portuguese ancestry (n = 139, P = 0.4), but no association among patients of Japanese ancestry (n = 151, P = 0.8). Our study demonstrates that an allele associated with response to etanercept therapy is also associated with CD84 gene expression, and further that CD84 expression correlates with disease activity. These findings support a model in which CD84 genotypes and/or expression may serve as a useful biomarker for response to etanercept treatment in RA patients of European ancestry. © 2013 Cui et al