New Look at the North

Reports Canadian Armed Forces activities planned with the new 35-man Northern Region Headquarters at Yellowknife Jan 1971, under Brig-Gen Ramsey Withers, who is familiar with the area, its people and its social codes. Bridge construction, airstrip improvement, search and rescue operations and surveillance of pollution limits are among planned activities, with efforts to train Eskimos and Indians for nontechnical jobs

The Sum of the Parts: Lessons Learnt from Designing and Building a 3.7 Metre S/X-Band Antenna

A redundant 2.2m Cossor weather radar was made available to us. After some initial experimentation tracking NOAA weather satellites, we challenged ourselves to convert it into a reliable high performance S/X-Band Station suitable for supporting LEO missions. A new reflector, horn feed, RF chain, motors and gearing were specified, designed and installed during the upgrade. Modern control software was written to command the new antenna. We found that designing and assembling such a system is educational at a both a systems and component level. In particular, at X-Band we found there is little margin for errors where many small details, such as keyholing, pointing accuracy, feedback, gearing and RF chain considerations require careful engineering to give reliable performance

Development of an Antenna Positioner for S- and X-Band Ground Segment

Through careful engineering and a little serendipity we have designed and built a commercial-grade 3.7 m S/X- band antenna, positioning system, full predictive ACU and scheduler from a mix of surplus and cheaply sourced parts. The predictive ACU is ready for commercialisation

A New Approach to High Reliability UHF Controllers

Many available UHF antenna positioners lack reliability for high-intensity commercial use. Similarly, many UHF antenna controllers lack appropriate interfaces for remote and automated control. We present a number of ways to simplify UHF ground station design and improve reliability. We also describe an improved antenna controller we have designed, with Ethernet connectivity, human- and machine-friendly interfaces, detailed metrics for fault diagnosis, and an improved control algorithm designed to minimise gearbox stresses and improve pointing accuracy

A Bistatic Ground Station for Concurrent Spacecraft Operations

It is common for SmallSat and CubeSat operators to implement telecommunication systems using a half-duplex UHF system to reduce the cost and complexity of spcecraft hardware. This half-duplex configuration requires transmission and reception of the spacecraft signals at the same frequency, with the 402 MHz to 403 MHz band being a popular choice. Due to practical filter limitations, it is impossible to produce an analogue filter for a ground-based receiver which can sufficiently attenuate transmissions from neighboring transmitters also operating in the same 402-403 MHz, band while still retaining a sufficiently low insertion loss to clearly receive tranmissions from a spacecraft. As a result, only one such half-duplex ground station can operate in the 402-403 MHZ frequency band in any local area at any one time. We developed a bi-static station where the transmitting station is some 15 kilometers distant from the receiving station, allowing multiple concurrent spacecraft passes. Such an approach makes supporting UHF missions economic for ground station providers

The differential regulation of Lck kinase phosphorylation sites by CD45 is critical for T cell receptor signaling responses

SummaryThe molecular mechanisms whereby the CD45 tyrosine phosphatase (PTPase) regulates T cell receptor (TCR) signaling responses remain to be elucidated. To investigate this question, we have reconstituted CD45 (encoded by Ptprc)-deficient mice, which display severe defects in thymic development, with five different expression levels of transgenic CD45RO, or with mutant PTPase null or PTPase-low CD45R0. Whereas CD45 PTPase activity was absolutely required for the reconstitution of thymic development, only 3% of wild-type CD45 activity restored T cell numbers and normal cytotoxic T cell responses. Lowering the CD45 expression increased CD4 lineage commitment. Peripheral T cells with very low activity of CD45 phosphatase displayed reduced TCR signaling, whereas intermediate activity caused hyperactivation of CD4+ and CD8+ T cells. These results are explained by a rheostat mechanism whereby CD45 differentially regulates the negatively acting pTyr-505 and positively acting pTyr-394 p56lck tyrosine kinase phosphorylation sites. We propose that high wild-type CD45 expression is necessary to dephosphorylate p56lck pTyr-394, suppressing CD4 T+ cell lineage commitment and hyperactivity

Bicontinuous minimal surface nanostructures for polymer blend solar cells

This paper presents the first examination of the potential for bicontinuous structures such as the gyroid structure to produce high efficiency solar cells based on conjugated polymers. The solar cell characteristics are predicted by a simulation model that shows how the morphology influences device performance through integration of all the processes occurring in organic photocells in a specified morphology. In bicontinuous phases, the surface de. ning the interface between the electron and hole transporting phases divides the volume into two disjoint subvolumes. Exciton loss is reduced because the interface at which charge separation occurs permeates the device so excitons have only a short distance to reach the interface. As each of the component phases is connected, charges will be able to reach the electrodes more easily. In simulations of the current-voltage characteristics of organic cells with gyroid, disordered blend and vertical rod (rods normal to the electrodes) morphologies, we find that gyroids have a lower than anticipated performance advantage over disordered blends, and that vertical rods are superior. These results are explored thoroughly, with geminate recombination, i.e. recombination of charges originating from the same exciton, identified as the primary source of loss. Thus, if an appropriate materials choice could reduce geminate recombination, gyroids show great promise for future research and applications

Relationship skills building with older adults

Relationship skills building is the focus of an innovative clinical experience with older adults for junior level nursing students in a psychiatric mental health course. The clinical experience is designed to help students apply, integrate, and validate previously learned therapeutic communication skills and experience discovery of self and others. This article describes a clinical experience that introduces students to older adults, who will make up the majority of health care recipients in the students’ future careers, and helps students explore the nurse’s role in mental health care for older adults. Not only did students engaged in the clinical experience learn to develop a relationship with the older adults, but they learned much more— they learned to appreciate the value of life, the importance of listening, and the rich and varied life stories of older adults

Expanded directly binds conserved regions of Fat to restrain growth via the Hippo pathway

The Hippo pathway is a conserved and critical regulator of tissue growth. The FERM protein Expanded is a key signaling hub that promotes activation of the Hippo pathway, thereby inhibiting the transcriptional co-activator Yorkie. Previous work identified the polarity determinant Crumbs as a primary regulator of Expanded. Here, we show that the giant cadherin Fat also regulates Expanded directly and independently of Crumbs. We show that direct binding between Expanded and a highly conserved region of the Fat cytoplasmic domain recruits Expanded to the apicolateral junctional zone and stabilizes Expanded. In vivo deletion of Expanded binding regions in Fat causes loss of apical Expanded and promotes tissue overgrowth. Unexpectedly, we find Fat can bind its ligand Dachsous via interactions of their cytoplasmic domains, in addition to the known extracellular interactions. Importantly, Expanded is stabilized by Fat independently of Dachsous binding. These data provide new mechanistic insights into how Fat regulates Expanded, and how Hippo signaling is regulated during organ growth

Noticing education campaigns or public health messages about vaping among youth in the US, Canada, and England from 2018 to 2022

Purpose: Public health campaigns have the potential to correct vaping misperceptions. However, campaigns highlighting vaping harms to youth may increase misperceptions that vaping is equally/more harmful than smoking. Vaping campaigns have been implemented in the US and Canada since 2018, and in England since 2017, but with differing focus: youth vaping prevention (US/Canada) and smoking cessation (England). We therefore examined country differences and trends in noticing vaping campaigns among youth and, using 2022 data only, perceived valence of campaigns and associations with harm perceptions. Methods: Seven repeated cross-sectional surveys of 16–19-year-olds in US, Canada, England (2018-2022, N=92,339). Results: Over half of youth reported noticing vaping campaigns, and noticing increased from Aug’18-Feb’20 (US:55.2-74.6%,AOR=1.21,95%CI=1.18-1.24; Canada:52.6-64.5%,AOR=1.13,1.11-1.16; England:48.0-53.0%,AOR=1.05,1.02-1.08) before decreasing (Canada) or plateauing (England/US) to Aug’22. Increases were most pronounced in the US, then Canada. Noticing was most common on websites/social media, school, and television/radio. In 2022 only, most campaigns were perceived to negatively portray vaping and this was associated with accurately perceiving vaping as less harmful than smoking among youth who exclusively vaped (AOR=1.46,1.09-1.97). Conclusion: Consistent with implementation of youth vaping prevention campaigns in the US and Canada, most youth reported noticing vaping campaigns/messages, and most were perceived to negatively portray vaping