The Iroquoian Sweat Lodges of Dorchester Village

During the Middle Iroquoian period (1300-1400 A.D.), semi-subterranean sweat lodges were structures commonly built on the inside of longhouses in Southern Ontario (Parks, 2018). These structures are known to have been used for health, social, and spiritual purposes (P. Timmins: personal communication, 2022). Stratigraphically, the basal layers of sweat lodges can yield artifacts that were used during shamanistic rituals and social ceremonies that took place within the structures (Parks, 2018). The lack of research on sweat lodges simply highlights the broader need to learn more about indigenous cultures across Ontario, both in prehistoric and modern contexts. In this report, the examination of the types of artifacts found in the basal and the infill layers of three sweat lodges aim to help provide further insight into the use-life of these structures and their cultural significance

Self-Interacting Dark Matter Subhalos in the Milky Way's Tides

We study evolution of self-interacting dark matter (SIDM) subhalos in the Milky Way (MW) tidal field. The interaction between the subhalos and the MW's tides lead to more diverse dark matter distribution in the inner region, compared to their cold dark matter counterparts. We test this scenario with two MW satellite galaxies, Draco and Fornax, opposite extremes in the inner dark matter content, and find that they can be accommodated within the SIDM model proposed to explain the diverse rotation curves of spiral galaxies in the field.Comment: 6 pages, 3 figures. Updated figures and text. Accepted for publication in PR

Surprising Evolution of the Parsec-scale Faraday Rotation Gradients in the Jet of the BL Lac Object B1803+784

Several multi-frequency polarization studies have shown the presence of systematic Faraday Rotation gradients across the parsec-scale jets of Active Galactic Nuclei (AGN), taken to be due to the systematic variation of the line-of-sight component of a helical magnetic (B) field across the jet. Other studies have confirmed the presence and sense of these gradients in several sources, thus providing evidence that these gradients persist over time and over large distances from the core. However, we find surprising new evidence for a reversal in the direction of the Faraday Rotation gradient across the jet of B1803+784, for which multi-frequency polarization observations are available at four epochs. At our three epochs and the epoch of Zavala & Taylor (2003), we observe transverse Rotation Measure (RM) gradients across the jet, consistent with the presence of a helical magnetic field wrapped around the jet. However, we also observe a "flip" in the direction of the gradient between June 2000 and August 2002. Although the origins of this phenomena are not entirely clear, possibly explanations include (i) the sense of rotation of the central supermassive black hole and accretion disc has remained the same, but the dominant magnetic pole facing the Earth has changed from North to South; (ii) a change in the direction of the azimuthal B field component as a result of torsional oscillations of the jet; and (iii) a change in the relative contributions to the observed rotation measures of the "inner" and "outer" helical fields in a magnetic-tower model. Although we cannot entirely rule out the possibility that the observed changes in the RM distribution are associated instead with changes in the thermal-electron distribution in the vicinity of the jet, we argue that this explanation is unlikely.Comment: 21 pages, 10 figures. Accepted for publication in MNRA

The impact of baryonic discs on the shapes and profiles of self-interacting dark matter halos

We employ isolated N-body simulations to study the response of self-interacting dark matter (SIDM) halos in the presence of the baryonic potentials. Dark matter self-interactions lead to kinematic thermalization in the inner halo, resulting in a tight correlation between the dark matter and baryon distributions. A deep baryonic potential shortens the phase of SIDM core expansion and triggers core contraction. This effect can be further enhanced by a large self-scattering cross section. We find the final SIDM density profile is sensitive to the baryonic concentration and the strength of dark matter self-interactions. Assuming a spherical initial halo, we also study evolution of the SIDM halo shape together with the density profile. The halo shape at later epochs deviates from spherical symmetry due to the influence of the non-spherical disc potential, and its significance depends on the baryonic contribution to the total gravitational potential, relative to the dark matter one. In addition, we construct a multi-component model for the Milky Way, including an SIDM halo, a stellar disc and a bulge, and show it is consistent with observations from stellar kinematics and streams.Comment: 10 pages, 8 figures, submitted to MNRAS, accepted for publication in MNRA

Acceptability and Feasibility of Web-based Diabetes Instruction for Latinos with Limited Education and Computer Experience

Introduction: The internet offers an important avenue for developing diabetes self-management skills, but many Latinos have limited experience with computer-based instruction. Objective: To evaluate the feasibility and acceptability of delivering a web-based diabetes education program in a computer classroom for Spanish-speaking Latinos. Methods: Spanish-speaking Latinos (n=26) attended two classroom sessions to learn computer skills while navigating a web-based diabetes education platform. Diabetes knowledge was assessed before and after the intervention; structured interviews were completed to assess program acceptability. Results: Half of participants (50%) had not previously used a computer. Post-intervention, diabetes knowledge improved significantly (p=.001). The majority of participants (86%) indicated a preference for web-based instruction as a stand-alone program or as an adjunct to traditional classroom training, particularly citing the advantage of being able to engage the material at their own pace. Conclusion: With limited support, Latinos with minimal computer experience can effectively engage in web-based diabetes education

Diversity, abundance, and distribution of ground invertebrates in Lower Sharpham Farm

Invertebrates constitute the largest group of animals on Earth and represent the bulk of biodiversity. They are responsible for numerous essential ecosystems services and are at the centre of many terrestrial food webs. Due to habitat loss from land use change and conversion to intensive agriculture, they are experiencing a substantial decline in biodiversity, hence conservation approaches such as rewilding have been sought. There are limited studies of invertebrate biodiversity in rewilding projects, therefore the aim of this study is to investigate the diversity and abundance of ground invertebrates at Lower Sharpham Farm and the influences of vegetation structure in a rewilded field and a farmed field. 18 pitfall traps were installed in each field divided into 3 groups of 6 and were left outside for 5 days. After collection, 856 invertebrates were found and identified in the laboratory. During that period, a vegetation survey was also carried out. Results within rewilded field indicate that group 1 showed to have a higher invertebrate abundance (n=205) and species richness (n=15) with higher biodiversity index (H=1.88). Results within farmed field indicate that the area in group 1 showed to have a higher invertebrate abundance (n=124) while group 3 had a higher species richness (n=13) with a higher biodiversity index result (H=2.12). Results between fields comparison indicate that rewilded fields increase invertebrate abundance (n=559), though grazing in farmed fields has little effect on invertebrate richness but decreases abundance (n=297). Farmed field had a slightly higher biodiversity index result (H=1.87) compared to rewilded field (H=1.82) due to the high dominance of springtails (Entomobryomorpha). This study determines that rewilding works as a tool for promoting invertebrate abundance and that organic farms have a positive impact on invertebrate diversity. Overall, long-term regular monitoring is needed to evaluate the success of rewilding for biodiversity overtime. The outcomes of the study not only evidence the importance of rewilding for invertebrate conservation but also the importance of low intensive agriculture practices for biodiversity

Radio Circular Polarization Produced in Helical Magnetic Fields in Eight Active Galactic Nuclei

Homan & Lister (2006) have recently published circular-polarization (CP) detections for 34 objects in the MOJAVE sample - a set of bright, compact AGN being monitored by the Very Long Baseline Array at 15 GHz. We report the detection of 15-GHz parsec-scale CP in two more AGN (3C345 and 2231+114), and confirm the MOJAVE detection of CP in 1633+382. It is generally believed that the most likely mechanism for the generation of this CP is Faraday conversion of linear polarization to CP. A helical jet magnetic-field (B-field) geometry can facilitate this process - linearly polarized emission from the far side of the jet is converted to CP as it passes through the magnetised plasma at the front side of the jet on its way toward the observer. In this case, the sign of the generated CP is essentially determined by the pitch angle and helicity of the helical B field. We have determined the pitch-angle regimes and helicities of the helical jet B fields in 8 AGN for which parsec-scale CP has been detected, and used them to predict the expected CP signs for these AGN if the CP is generated via conversion in these helical fields. We have obtained the intriguing result that our predictions agree with the observed signs in all eight cases, provided that the longitudinal B-field components in the jets correspond to South magnetic poles. This clearly non-random pattern demonstrates that the observed CP in AGN is directly associated with the presence of helical jet B fields. These results suggest that helical B fields are ubiquitous in AGN jets.Comment: 24 pages, 6 figures, accepted for publication in Monthly Notices of the Royal Astronomical Society (MNRAS

Probing the central black hole in M87 with gamma-rays

Recent high-sensitivity observation of the nearby radio galaxy M87 have provided important insights into the central engine that drives the large-scale outflows seen in radio, optical and X-rays. This review summarizes the observational status achieved in the high energy (HE;<100 GeV) and very high energy (VHE; >100 GeV) gamma-ray domains, and discusses the theoretical progress in understanding the physical origin of this emission and its relation to the activity of the central black hole.Comment: Invited compact review to be published in Modern Physics Letters A; 19 pages, 4 figure

Diode area melting single-layer parametric analysis of 316L stainless steel powder

Diode area melting (DAM) is a novel additive manufacturing process that utilises customised architectural arrays of low power laser diode emitters for high speed parallel processing of metallic powdered feedstock. The laser diodes operate at shorter laser wavelengths (808 nm) than conventional SLM fibre lasers (1064 nm) theoretically enabling more efficient energy absorption for specific materials. This investigation presents a parametric analysis of the DAM process, identifying the effect of powder characteristics, laser beam profile, laser power and scan speed on the porosity of a single-layer sample. Also presented is the effect of process energy density on melt pool depth (irradiated thermal energy penetration capable of achieving melting) on 316L stainless steel powder. An analysis of the density and the melt depth fraction of single layers is presented in order to identify the conditions that lead to the fabrication of fully dense DAM parts. Energy densities in excess of 86 J/mm3 were theorised as sufficient to enable processing of fully dense layers