Velocity weakening and possibility of aftershocks in nanofriction experiments

We study the frictional behavior of small contacts as those realized in the atomic force microscope and other experimental setups, in the framework of generalized Prandtl-Tomlinson models. Particular attention is paid to mechanisms that generate velocity weakening, namely a decreasing average friction force with the relative sliding velocity.The mechanisms studied model the possibility of viscous relaxation, or aging effects in the contact. It is found that, in addition to producing velocity weakening, these mechanisms can also produce aftershocks at sufficiently low sliding velocities. This provides a remarkable analogy at the microscale, of friction properties at the macroscale, where aftershocks and velocity weakening are two fundamental features of seismic phenomena.Comment: 8 pages, 7 figure

The new approach to rabbit poisoning 1080 and improved methods

The rabbit in Australia has only a relatively short history*, but during that period, of 168 years, has probably done more harm to this country than any other pest. In Western Australia, as in some of the other States, investigations directed towards the improvement of control methods—particularly poisoning—have been intensified over recent years. Although it is recognised that no single method could accomplish eradication or give completely satisfactory control, it is also evident that the improvement of poisoning methods could help greatly. Some of our investigations have been aimed at improving techniques in poisoning procedure and also in finding better poisons. One of the new poisons, 1080 (sodium fluoroacetate) has proved very effective

The Stokes-Einstein Relation in Supercooled Aqueous Solutions of Glycerol

The diffusion of glycerol molecules decreases with decreasing temperature as its viscosity increases in a manner simply described by the Stokes-Einstein(SE) relation. Approaching the glass transition, this relation breaks down as it does with a number of other pure liquid glass formers. We have measured the diffusion coefficient for binary mixtures of glycerol and water and find that the Stokes-Einstein relation is restored with increasing water concentration. Our comparison with theory suggests that addition of water postpones the formation of frustration domainsComment: 4 Pages and 3 Figure

Speech and language therapy versus placebo or no intervention for speech problems in Parkinson's disease

Parkinson's disease patients commonly suffer from speech and vocal problems including dysarthric speech, reduced loudness and loss of articulation. These symptoms increase in frequency and intensity with progression of the disease). Speech and language therapy (SLT) aims to improve the intelligibility of speech with behavioural treatment techniques or instrumental aids

Phage display selected magnetite interacting Adhirons for shape controlled nanoparticle synthesis

Adhirons are robust, well expressing, peptide display scaffold proteins, developed as an effective alternative to traditional antibody binding proteins for highly specific molecular recognition applications. This paper reports for the first time the use of these versatile proteins for material binding, and as tools for controlling material synthesis on the nanoscale. A phage library of Adhirons, each displaying two variable binding loops, was screened to identify specific proteins able to interact with [100] faces of cubic magnetite nanoparticles. The selected variable regions display a strong preference for basic residues such as lysine. Molecular dynamics simulations of amino acid adsorption onto a [100] magnetite surface provides a rationale for these interactions, with the lowest adsorption energy observed with lysine. These proteins direct the shape of the forming nanoparticles towards a cubic morphology in room temperature magnetite precipitation reactions, in stark contrast to the high temperature, harsh reaction conditions currently used to produce cubic nanoparticles. These effects demonstrate the utility of the selected Adhirons as novel magnetite mineralization control agents using ambient aqueous conditions. The approach we outline with artificial protein scaffolds has the potential to develop into a toolkit of novel additives for wider nanomaterial fabrication

Antibody mimetic receptor proteins for label-free biosensors

The development of high sensitivity biosensors, for example for clinical diagnostics, requires the identification of suitable receptor molecules which offer high stability, specificity and affinity, even when embedded into solid-state biosensor transducers. Here, we present an electrochemical biosensor employing small synthetic receptor proteins (Mw < 15 kDa) which emulate antibodies but with improved stability, sensitivity and molecular recognition properties, in particular when immobilized on a solid sensor surface. The synthetic receptor protein is a non-antibody-based protein scaffold with variable peptide regions inserted to provide the specific binding, and was designed to bind anti-myc tag antibody (Mw � 150 kDa), as a proof-of-principle exemplar. Both the scaffold and the selected receptor protein were found to have high thermostability with melting temperatures of 101 �C and 85 �C, respectively. Furthermore, the secondary structures of the receptor protein were found to be very similar to that of the original native scaffold, despite the insertion of variable peptide loops that create the binding sites. A label-free electrochemical sensor was fabricated by functionalising a microfabricated gold electrode with the receptor protein. A change in the phase of the electrochemical impedance was observed when the biosensor was subjected to anti-myc tag antibodies at concentrations between 6.7 pM and 6.7 nM. These findings demonstrate that these non-antibody receptor proteins are excellent candidates for recognition molecules in label-free biosensors

History of scoria-cone eruptions on the eastern shoulder of the Kenya–Tanzania Rift revealed in the 250-ka sediment record of Lake Chala near Mount Kilimanjaro

Reconstructions of the timing and frequency of past eruptions are important to assess the propensity for future volcanic activity, yet in volcanic areas such as the East African Rift only piecemeal eruption historiesexist. Understanding thevolcanichistory of scoria‐conefields, whereeruptionsare often infrequentand deposits strongly weathered, is particularly challenging. Here we reconstruct a history of volcanism from scoria cones situated along the eastern shoulders of the Kenya–Tanzania Rift, using a sequence of tephra (volcanic ash) layers preserved in the ~250‐ka sediment record of Lake Chala near Mount Kilimanjaro. Seven visible and two non‐visible (crypto‐) tephra layers in the Lake Chala sequence are attributed to activity from the Mt Kilimanjaro (northern Tanzania) and the Chyulu Hills (southern Kenya) volcanic fields, on the basis of their glass chemistry, textural characteristics and known eruption chronology. The Lake Chala record of eruptions from scoria cones in the Chyulu Hills volcanic field confirms geological and historical evidence of its recent activity, and provides first‐order age estimates for seven previously unknown eruptions. Long and well‐resolved sedimentary records such as that of Lake Chala have significant potential for resolving regional eruption chronologies spanning hundreds of thousands of years.NERC (NE/ P011969/1

The Psy-Security-Curriculum ensemble: British Values curriculum policy in English schools

Framed as being in response to terrorist attacks and concerns about religious bias in some English schools, ‘British Values’ (BV) curriculum policy forms part of the British Government’s Counter-Terrorism and Security Act, 2015. This includes a Duty on teachers in England to actively promote British Values to deter students from radicalisation. This paper, first, traces the history of Britishness in the curriculum to reveal a prevalence of nationalistic, colonial values. Next, an ensemble of recent policies and speeches focusing on British Values is analysed, using a psycho-political approach informed by anti-colonial scholarship. Finally, we interrogate two key critiques of the British Values curriculum discourse: the universality of British Values globally, and concerns over the securitisation of education. Findings indicate that the constitution of white British supremacist subjectivities operate through curriculum as a defence mechanism against perceived threats to white privilege, by normalising a racialised state-controlled social order. The focus is on ‘British’ values, but the analytic framework and findings have wider global significance

Airborne multiwavelength High Spectral Resolution Lidar (HSRL-2) observations during TCAP 2012 : Vertical profiles of optical and microphysical properties of a smoke/urban haze plume over the northeastern coast of the US

© Author(s) 2014. This work is distributed under the Creative Commons Attribution 3.0 License.We present measurements acquired by the world's first airborne 3 backscatter (&beta;) + 2 extinction (α) High Spectral Resolution Lidar (HSRL-2). HSRL-2 measures particle backscatter coefficients at 355, 532, and 1064 nm, and particle extinction coefficients at 355 and 532 nm. The instrument has been developed by the NASA Langley Research Center. The instrument was operated during Phase 1 of the Department of Energy (DOE) Two-Column Aerosol Project (TCAP) in July 2012. We observed pollution outflow from the northeastern coast of the US out over the western Atlantic Ocean. Lidar ratios were 50-60 sr at 355 nm and 60-70 sr at 532 nm. Extinction-related Ångström exponents were on average 1.2-1.7, indicating comparably small particles. Our novel automated, unsupervised data inversion algorithm retrieved particle effective radii of approximately 0.2 μm, which is in agreement with the large Ångström exponents. We find good agreement with particle size parameters obtained from coincident in situ measurements carried out with the DOE Gulfstream-1 aircraft.Peer reviewedFinal Published versio

Childhood Cancer Survival in the Highly Vulnerable Population of South Texas: Persistent Challenges for Adolescents and Hispanic Ethnicity

Background: This study examines childhood cancer survival rates and prognostic factors related to survival in the majority Hispanic population of South Texas (STX), whereas most other population studies in childhood cancer survival focus on populations with relatively few Hispanics. Methods: The population-based cohort study used Texas Cancer Registry data (1995-2017) to examine survival and prognostic factors. Results: The 5-year relative survival rate for STX cancer patients diagnosed at 0–19 years was 80.3% for all races/ethnicity. Hispanics had statistically significant lower 5-year relative survival rates than non-Hispanic Whites (NHW) for male and female together diagnosed at age ≥ 5 years. When comparing survival among Hispanics and NHW for the most common cancer, acute lymphocytic leukemia (ALL), the difference was most striking in the 15-19 years age range, with 47.7% Hispanic patients surviving at 5 years compared to 78.4% of NHW counterparts. The multivariable-adjusted analysis showed that males [hazard ratio (HR): 1.13], patients diagnosed at age \u3c 1 year (HR: 1.69), at 10–14 year (HR: 1.42), or at 15–19 years (HR: 1.40), and Hispanics (HR: 1.38) had significantly increased mortality risk compared to the corresponding counterparts for all cancers. Conclusions: STX Hispanics had lower 5-year relative survival than NHW especially for ALL. Male gender, diagnosis at age \u3c 1 year or 10–19 years were also associated with decreased childhood cancer survival. Despite advances in treatment, Hispanics lag significantly behind NHW. Further cohort studies in STX are warranted to identify additional factors affecting survival and to develop interventional strategies