Local dimensions of self-similar measures satisfying the finite neighbour condition

KEH was supported by NSERC Grant 2016-03719. AR was supported by this grant as well as EPSRC Grant EP/V520123/1.We study sets of local dimensions for self-similar measures in R satisfying the finite neighbour condition, which is formally stronger than the weak separation condition (WSC) but satisfied in all known examples. Under a mild technical assumption, we establish that the set of attainable local dimensions is a finite union of (possibly singleton) compact intervals. The number of intervals is bounded above by the number of non-trivial maximal strongly connected components of a finite directed graph construction depending only on the governing iterated function system. We also explain how our results allow computations of the sets of local dimensions in many explicit cases. This contextualises and generalises a vast amount of prior work on sets of local dimensions for self-similar measures satisfying the WSC.Publisher PDFPeer reviewe

Mayan housing types, looking at layouts, structure, and architecture

https://scholarworks.moreheadstate.edu/student_scholarship_posters/1153/thumbnail.jp

A persistent mid-water column hypoxic zone with low pH and CaCO3 saturation state in Toba Inlet

Oxygen concentrations in many coastal areas have declined over the last several decades, increasing the prevalence of low oxygen zones and hypoxia ([O2] \u3c 63 µmol kg-1). This trend is driven by warming temperatures that decrease oxygen solubility, biological metabolism, and ocean stratification, as well as by anthropogenic nutrient loading. Coastal waters, however, also contain environments naturally predisposed to low-oxygen concentrations, particularly in fjords where sills restrict sub-surface water exchange and associated re-oxygenation, and geography constrains freshwater runoff and nutrient loadings. Low-oxygen waters are also commonly associated with low pH and conditions corrosive to CaCO3 through mechanistic links between processes related to both deoxygenation and the inorganic carbon system. Such settings are therefore sensitive to further oxygen decline and additional carbon inputs, making them vulnerable to both hypoxia and ocean acidification. Here, we identify and characterize a persistent mid-water column hypoxic zone with regionally low pH in Toba Inlet in the northern Salish Sea, and evaluate the processes controlling this feature. The hypoxic zone is present year-round and is most intense near the fjord head, but extends seaward across the entire fjord (~ 40 km) at its greatest extent, often encompassing \u3e 200 m of the water column. However, in contrast with typical fjord systems, Toba Inlet does not contain a sill, but joins several deep channels that connect to the Strait of Georgia at roughly twice the oxygen minimum depth, commonly observed around 100 m deep. Together, these characteristics imply additional processes to sub-surface water exchange maintain the extent and intensity of hypoxia and low seawater pH conditions in Toba Inlet. We investigate a suite of processes including sub-surface water exchange, riverine input, and biological production and respiration, to develop a simple model to explain the oxygen and inorganic carbon characteristics in Toba Inlet

Results from the Baynes Sound Environmental Intelligence Collaboration (BaSEIC)

Baynes Sound, in the northern Salish Sea, hosts more than 50% of the BC shellfish aquaculture industry, with Pacific oyster (Magallana gigas) as the dominant production species. The known vulnerability of this species to ocean acidification (OA)-driven changes in seawater chemistry – specifically through alteration in calcium carbonate (CaCO3) mineral stability, combined with periodic production problems in Baynes Sound – have led to a growing concern regarding possible contemporaneous impacts of OA in spite of lacking environmental intelligence detailing baseline conditions. In order to build our understanding of current biogeochemical patterns in this key Salish Sea setting, the BC Shellfish Growers Association and the Hakai Institute, with support from partnering shellfish growers, the Province of British Columbia and the Tula Foundation, formed a research initiative, known as the Baynes Sound Environmental Intelligence Collaboration (BaSEIC), in early 2016. Seasonally-resolved and spatially-distributed discrete seawater samples were collected by shellfish growers and an independent citizen science group operating in the area. Discrete measurements were used to add spatial context to a high-frequency data stream produced by instrumentation installed at a shore-side facility for continuous observing of in situ (8 m) CO2 chemistry. Taken together, the discretely-collected and continuously-measured seawater CO2 data provide a dynamic picture of the baseline conditions in Baynes Sound, including: (1) a pronounced seasonal cycle with surface-focused favorable conditions for CaCO3 mineral precipitation between spring and early autumn, (2) a sharp decrease in mineral stability of sub-surface water including excursions toward CaCO3 undersaturated conditions during the winter season and summer neap tides, and (3) a seasonal north-south gradient in mineral stability. These results illustrate the current CO2 system patterns in Baynes Sound that are now being considered in shellfish industry management discussions

Risk of sexual recidivism as a function of age and actuarial risk

The study of risk for sexual recidivism has undergone substantial development in recent years. The foundation for advances in this area has been the use of actuarial measures to identify subgroups of offenders with different observed rates of sexual re-offending over time. An unresolved issue within this research area has been the moderating function of age in the assessment of risk. The current study examined sexual re-offending as a function of age and actuarial risk in a large sample of sexual offenders released from prison between 1990 and 2004. There was an overall decrease in the rate of sexual re-offending over the age of 50. However, a small group of offenders from the higher actuarial risk categories of the older age groups continued to re-offend at higher rates than their lower-risk peers. <br /

An investigation of the effects of driver age when using novel navigation systems in a head-up display

Although drivers gain experience with age, many older drivers are faced with age-related deteriorations that can lead to a higher crash risk. Head-Up Displays (HUDs) have been linked to significant improvements in driving performance for older drivers by tackling issues related to aging. For this study, two Augmented Reality (AR) HUD virtual car navigation solutions were tested (one screen-fixed, one world-fixed), aiming to improve navigation performance and reduce the discrepancy between younger and older drivers by aiding the appropriate allocation of attention and easing interpretation of navigational information. Twenty-five participants (12 younger, 13 older) undertook a series of drives within a medium-fidelity simulator with three different navigational conditions (virtual car HUD, static HUD arrow graphic and traditional head-down satnav). Results showed that older drivers tended to achieve navigational success rates similar to the younger group, but experienced higher objective mental workload. Solely for the static HUD arrow graphic, differences in most workload questionnaire items and objective workload between younger and older participants were not significant. The virtual car led to improved navigation performance of all drivers, compared to the other systems. Hence, both AR HUD systems show potential for older drivers, which needs to be further investigated in a real-world driving context

Strategic analysis for the MER Cape Verde approach

The Mars Exploration Rover Opportunity has recently completed a two year campaign studying Victoria Crater. The campaign culminated in a close approach of Cape Verde in order to acquire high resolution imagery of the exposed stratigraphy in the cliff face. The close approach to Cape Verde provided significant challenges for every subsystem of the rover as the rover needed to traverse difficult, un-characterised terrain and approach a cliff face with the potential of blocking out solar energy and communications with Earth. In this paper we describe the strategic analyses performed by the science and engineering teams so that we could successfully achieve the science objectives while keeping the rover safe

Maximizing the value of Solar System data through Planetary Spatial Data Infrastructures

Planetary spatial data returned by spacecraft, including images and higher-order products such as mosaics, controlled basemaps, and digital elevation models (DEMs), are of critical importance to NASA, its commercial partners and other space agencies. Planetary spatial data are an essential component of basic scientific research and sustained planetary exploration and operations. The Planetary Data System (PDS) is performing the essential job of archiving and serving these data, mostly in raw or calibrated form, with less support for higher-order, more ready-to-use products. However, many planetary spatial data remain not readily accessible to and/or usable by the general science user because particular skills and tools are necessary to process and interpret them from the raw initial state. There is a critical need for planetary spatial data to be more accessible and usable to researchers and stakeholders. A Planetary Spatial Data Infrastructure (PSDI) is a collection of data, tools, standards, policies, and the people that use and engage with them. A PSDI comprises an overarching support system for planetary spatial data. PSDIs (1) establish effective plans for data acquisition; (2) create and make available higher-order products; and (3) consider long-term planning for correct data acquisition, processing and serving (including funding). We recommend that Planetary Spatial Data Infrastructures be created for all bodies and key regions in the Solar System. NASA, with guidance from the planetary science community, should follow established data format standards to build foundational and framework products and use those to build and apply PDSIs to all bodies. Establishment of PSDIs is critical in the coming decade for several locations under active or imminent exploration, and for all others for future planning and current scientific analysis.Comment: 8 pages, 0 figures. White paper submitted to the Planetary Science and Astrobiology Decadal Survey 2023-203

Mercury in the marine environment of the Canadian Arctic: Review of recent findings

AbstractThis review summarizes data and information which have been generated on mercury (Hg) in the marine environment of the Canadian Arctic since the previous Canadian Arctic Contaminants Assessment Report (CACAR) was released in 2003. Much new information has been collected on Hg concentrations in marine water, snow and ice in the Canadian Arctic. The first measurements of methylation rates in Arctic seawater indicate that the water column is an important site for Hg methylation. Arctic marine waters were also found to be a substantial source of gaseous Hg to the atmosphere during the ice-free season. High Hg concentrations have been found in marine snow as a result of deposition following atmospheric mercury depletion events, although much of this Hg is photoreduced and re-emitted back to the atmosphere. The most extensive sampling of marine sediments in the Canadian Arctic was carried out in Hudson Bay where sediment total Hg (THg) concentrations were low compared with other marine regions in the circumpolar Arctic. Mass balance models have been developed to provide quantitative estimates of THg fluxes into and out of the Arctic Ocean and Hudson Bay.Several recent studies on Hg biomagnification have improved our understanding of trophic transfer of Hg through marine food webs. Over the past several decades, Hg concentrations have increased in some marine biota, while other populations showed no temporal change. Marine biota also exhibited considerable geographic variation in Hg concentrations with ringed seals, beluga and polar bears from the Beaufort Sea region having higher Hg concentrations compared with other parts of the Canadian Arctic. The drivers of these variable patterns of Hg bioaccumulation, both regionally and temporally, within the Canadian Arctic remain unclear. Further research is needed to identify the underlying processes including the interplay between biogeochemical and food web processes and climate change

Differences in HIV Burden and Immune Activation within the Gut of HIV-Positive Patients Receiving Suppressive Antiretroviral Therapy

Background. The gut is a major reservoir for human immunodeficiency virus (HIV) in patients receiving antiretroviral therapy (ART). We hypothesized that distinct immune environments within the gut may support varying levels of HIV. Methods. In 8 HIV-1-positive adults who were receiving ART and had CD4+ T cell counts of >200 cells/µL and plasma viral loads of <40 copies/mL, levels of HIV and T cell activation were measured in blood samples and endoscopic biopsy specimens from the duodenum, ileum, ascending colon, and rectum. Results. HIV DNA and RNA levels per CD4+ T cell were higher in all 4 gut sites compared with those in the blood. HIV DNA levels increased from the duodenum to the rectum, whereas the median HIV RNA level peaked in the ileum. HIV DNA levels correlated positively with T cell activation markers in peripheral blood mononuclear cells (PBMCs) but negatively with T cell activation markers in the gut. Multiply spliced RNA was infrequently detected in gut, and ratios of unspliced RNA to DNA were lower in the colon and rectum than in PBMCs, which reflects paradoxically low HIV transcription, given the higher level of T cell activation in the gut. Conclusions. HIV DNA and RNA are both concentrated in the gut, but the inverse relationship between HIV DNA levels and T cell activation in the gut and the paradoxically low levels of HIV expression in the large bowel suggest that different processes drive HIV persistence in the blood and gut. Trial registration. ClinicalTrials.gov identifier: NCT00884793 (PLUS1