Background: Walking aids such as crutches, canes and walkers are used by 2 million Canadians. Repetitive weight-bearing with walking aids may cause upper limb peripheral nerve injury. The objectives of this review were to: 1) identify types of nerve injuries reported with walking aids; 2) report electrodiagnostic findings; 3) identify typical treatment strategies; and 4) determine expected recovery time for such injuries. Methods: MEDLINE, EMBASE, CINAHL and Cochrane Library were searched for primary data in English published between 1950-2022. Abstracts were reviewed independently by 2 authors. Full-text reviews were independently conducted by 2 authors. Results: The search identified 3746 abstracts, 43 of which underwent full-text review. 31 studies were included. There were 144 cases of peripheral nerve injury. Crutches caused the most injuries (n=21 studies). The ulnar nerve was most commonly injured (n=27 cases). Improper walking aid fit was identified as a risk factor in 74% of cases. Stopping walking aid use was the most common treatment strategy (n=10 studies). Follow-up reports (n=20) indicated 65% of patients experienced recovery at 6 months. Conclusions: Improper walking aid fit and use were identified as major injury risk factors. A national program to teach patients and clinicians how to use walking aids may reduce injury risk.

Lateral gaze aversions which follow reflective or thought provoking questions are called conjugated lateral eye movements (CLEMs). This response was studied in 20 schizophrenic patients, 20 depressive patients and 20 healthy controls. Frontal and parietal EEG measures were recorded simultaneously with the question/answer task. There were no differences in CLEMs among the 3 groups. Schizophrenic and depressive patients demonstrated a significantly reduced EEG-power on the left and an increased power on the right in comparison with healthy controls. This may point to a functional interhemispheric ‘disconnection’ in patients. Comparative correlations revealed EEG-power increase during the occurrence of contralateral CLEMs in the whole 10 min task.

The COllaborative project of Development of Anthropometrical measures in Twins (CODATwins) project is a large international collaborative effort to analyze individual-level phenotype data from twins in multiple cohorts from different environments. The main objective is to study factors that modify genetic and environmental variation of height, body mass index (BMI, kg/m2) and size at birth, and additionally to address other research questions such as long-term consequences of birth size. The project started in 2013 and is open to all twin projects in the world having height and weight measures on twins with information on zygosity. Thus far, 54 twin projects from 24 countries have provided individual-level data. The CODATwins database includes 489,981 twin individuals (228,635 complete twin pairs). Since many twin cohorts have collected longitudinal data, there is a total of 1,049,785 height and weight observations. For many cohorts, we also have information on birth weight and length, own smoking behavior and own or parental education. We found that the heritability estimates of height and BMI systematically changed from infancy to old age. Remarkably, only minor differences in the heritability estimates were found across cultural–geographic regions, measurement time and birth cohort for height and BMI. In addition to genetic epidemiological studies, we looked at associations of height and BMI with education, birth weight and smoking status. Within-family analyses examined differences within same-sex and opposite-sex dizygotic twins in birth size and later development. The CODATwins project demonstrates the feasibility and value of international collaboration to address gene-by-exposure interactions that require large sample sizes and address the effects of different exposures across time, geographical regions and socioeconomic status.

We present an indentation-scope that interfaces with confocal microscopy, enabling direct observation of the three-dimensional (3D) microstructural response of coatings on substrates. Using this method, we compared microns-thick polymer coatings on glass with and without silica nanoparticle filler. Bulk force data confirmed the >30% modulus difference, while microstructural data further revealed slip at the glass-coating interface. Filled coatings slipped more and about two times faster, as reflected in 3D displacement and von Mises strain fields. Overall, these data indicate that silica-doping of coatings can dramatically alter adhesion. Moreover, this method compliments existing theoretical and modeling approaches for studying indentation in layered systems.

The future of centimetre and metre-wave astronomy lies with the Square Kilometre Array (SKA), a telescope under development by a consortium of 17 countries that will be 50 times more sensitive than any existing radio facility. Most of the key science for the SKA will be addressed through large-area imaging of the Universe at frequencies from a few hundred MHz to a few GHz. The Australian SKA Pathfinder (ASKAP) is a technology demonstrator aimed in the mid-frequency range, and achieves instantaneous wide-area imaging through the development and deployment of phased-array feed systems on parabolic reflectors. The large field-of-view makes ASKAP an unprecedented synoptic telescope that will make substantial advances in SKA key science. ASKAP will be located at the Murchison Radio Observatory in inland Western Australia, one of the most radio-quiet locations on the Earth and one of two sites selected by the international community as a potential location for the SKA. In this paper, we outline an ambitious science program for ASKAP, examining key science such as understanding the evolution, formation and population of galaxies including our own, understanding the magnetic Universe, revealing the transient radio sky and searching for gravitational waves.

We used VLBI observations at 8.4 GHz between 1991 and 2005 to determine the motion of the RS CVn binary IM Pegasi (HR 8703), the guide star for the NASA/Stanford gyroscope relativity mission, Gravity Probe B (GP-B). The motion was determined relative to our primary reference, the core of the quasar 3C 454.3. The stability of this core was checked relative to two other extragalactic sources, B2250+194 and B2252+172, the former of which was tied to the ICRF. The core of 3C 454.3 is stationary relative to these two sources to within 30 μas yr−1 in each coordinate. IM Pegasi's radio morphology varies, but appears to be on average centered on the primary. We estimate the proper motion of IM Pegasi with a statistical standard error (sse) of 30 μas yr−1 in each coordinate. We also estimate the parallax with a statistical standard error of 75 μas and parameters of the orbit with sse's corresponding to 110 μas on the sky. Coupled with our upper limit of three times the sse on any systematic errors in each parameter %threefold higher upper limit on the systematic error contributions to each parameter estimate, these results ensure that the uncertainty of IM Pegasi's proper motion makes only a small contribution to the uncertainty of GP-B's tests of general relativity.

We present a selection of our VLBI images of SN 1993J, along with our latest results on its expansion and its shell structure.

We summarize our results on multi-epoch VLBI observations of SN 1979C in the galaxy M100 in Virgo, and of SN 1986 in the galaxy NGC 891. From t = 3.7 to 22 yr after the explosion, SN 1979C expands ∝ tm , almost freely, with m = 0.95 ± 0.03. For a total kinetic energy of 3 × 1051 erg, the expansion result requires a mass-loss to wind-velocity ratio for the progenitor of only 1 × 10−5 M⊙ yr−1per 10 km s−1, an order of magnitude smaller than estimated from radio light-curve fitting. We show a first image with slightly discernible structure of the supernova. For SN 1986J we present five images from 1987 to 2002 and show our result on moderately to strongly decelerated expansion with m = 0.71 ± 0.11. We comment on our result of an inversion of the radio spectrum in terms of the emergence of a possible pulsar nebula.

Twenty-two consecutive VLBI images of supernova 1993J in the galaxy M81 taken over 7 years show, in unprecedented detail, the dynamic evolution of the expanding radio shell of an exploded star. High precision astrometry using phase-referencing shows that the supernova expands isotropically, and that its geometric center has a formal proper motion of 190±110 km s−1 w.r.t. the core of M81. Systematic changes in the images most likely reflect a pattern of inhomogeneities in the medium left over from the progenitor star, or possibly instabilities in the expanding shell. As the shockfront sweeps up the medium, it is progressively decelerated, and after 7 years it has slowed to less than 1/2 its original expansion velocity. SN1993J is likely now entering the early stages of the adiabatic phase common in much older supernova remnants.

We have made 3.6 cm VLBI observations of the RS CVn binary star IM Pegasi (HR 8703) approximately four times per year since 1997 in support of the NASA/Stanford Relativity Gyroscope Experiment (Gravity Probe B). Phase-referenced maps reveal structural changes in the radio emission of the star on hour time scales during several of the sessions. Analyses of the VLBI phase delays with a Kalman-filter estimator reveal submilliarcsecond motions of the radio centroid of the star on hour and even subhour time scales. The observed structural changes and centroid motions often coincide with rapid changes in the star's flux density, as measured with the VLA. We report on our latest results and summarize our findings to date.

Twenty consecutive VLBI images of supernova 1993J in M81 from the time of explosion to the present show the dynamic evolution of the expanding radio shell of an exploded star. No clear sign of a pulsar nebula, expected to have a spectral luminosity 10 to 1,000 times larger than that of the Crab, has yet been seen. The upper limit on the brightness at 8.4 GHz in the center of the shell in one of the latest images is 0.15 mJy per beam of 0.4 mas2, corresponding to a spectral luminosity of that of the Crab. Any nebula that may have formed in the center is probably still obscured by the surrounding thermal matter with no substantial filamentation having yet occurred in the latter.

Three bright pulsars (B0950+08, B1133+16, and B1929+10) were observed with the 70-m radio telescope in Tidbinbilla at a frequency of 1650 MHz using the S2 Data Acquisition System which provided continuous recording of pulsar signals in two conjugate bands of B=16 MHz each. Parameters of microstructure have been analyzed using the predetection dispersion removal technique.

We report on VLA and VLBI observations of the nucleus of the nearby spiral galaxy M81. The VLA observations show the flux density of the nucleus to be variable by 50%. The VLBI observations indicate that the structure of the nucleus of M81 is somewhat variable on timescales of weeks.

M81 has been shown to have a compact flat-spectrum core with a possible steep-spectrum jet. We report on position determinations of the brightness peak of the nucleus relative to the position of the early supernova 1993J with uncertainties as low as 0.08 mas. At early epochs, the supernova was largely pointlike at any frequency and therefore an ideal phase reference. We describe how VLBI astrometry at several frequencies could be used to support a model with a core and a one-sided jet for the nucleus of M81.