Zero-free regions for multivariate Tutte polynomials (alias Potts-model partition functions) of graphs and matroids

The chromatic polynomial P_G(q) of a loopless graph G is known to be nonzero (with explicitly known sign) on the intervals (-\infty,0), (0,1) and (1,32/27]. Analogous theorems hold for the flow polynomial of bridgeless graphs and for the characteristic polynomial of loopless matroids. Here we exhibit all these results as special cases of more general theorems on real zero-free regions of the multivariate Tutte polynomial Z_G(q,v). The proofs are quite simple, and employ deletion-contraction together with parallel and series reduction. In particular, they shed light on the origin of the curious number 32/27.Comment: LaTeX2e, 49 pages, includes 5 Postscript figure

The role of community-based Hubs in reef restoration: Collaborative monitoring at Moore Reef

The Cairns-Port Douglas region is home to multiple coral rehabilitation and stewardship projects supported by scientists, Traditional Owners, and a range of local stakeholders. The Cairns-Port Douglas Reef Hub has been a platform for collaboration across Traditional Owners, tourism operators, not-for-profits and scientists from the Reef Restoration and Adaptation Program (AIMS and CSIRO) to design and deliver a project at Moore Reef that assesses how new techniques for assisted coral recovery can be applied in rubble habitats. The collaborative project evaluates the viability of newly engineered coral seeding devices developed by AIMS, for deploying coral recruits that were spawned in the National Sea Simulator in December 2022 to sites at Moore Reef close to tourist pontoons. This project provides important data to inform future scaling up of restoration activities and provides a model for active involvement of a range of partners. Through this work, the project builds understanding around key ingredients for best-practice, place-based engagement opportunities for Reef communities and the general public

Social rearing environment influences dog behavioral development

Early life experiences are known to influence behavior later in life. In dogs, environmental influences of early home rearing could be exploited to improve the chances of developing adult behavior most suited to the adult environment. For working dog organizations, such as Guide Dogs, suitable adult behavior is important to ensure that dogs can fulfill their role as guides for people with visual impairment. Here, we test the hypothesis that dogs' home rearing environment will influence behavioral development. To investigate this hypothesis, carers of potential guide dogs (puppy walkers) completed a questionnaire, termed the Puppy Walker Questionnaire (PWQ), about the dog's behavior at 5, 8, and 12 months of age. An additional 11 questions were answered about the home environment at the last assessment. Because no questionnaire existed which measured behavior most relevant to Guide Dogs, questions from an existing questionnaire (Canine Behaviour and Research Questionnaire) were combined with additional questions. Thus, a subsidiary aim of the study was to test the reliability of the PWQ for measuring behavioral development of potential guide dogs. The PWQ, scored on a 100-mm visual analogue scale, grouped into 5 new scales: trainability, distractibility, general anxiety, body sensitivity, and stair anxiety, with 4 Canine Behaviour and Research Questionnaire scales: excitability, separation-related behavior, attachment and attention seeking, and energy level. For each reliable scale, multivariate linear regression identified significant predictors from the home environmental questions. The results suggest that home rearing environment is indeed important for behavioral development: 9 of 11 environmental variables were significant predictors of behavioral scores. Those environmental variables that appeared most important were social in nature. Dogs were scored as higher in energy level, excitability, and distractibility if they had been raised in a home with children, lower on energy level and distractibility the more experience of puppy walking their carer had, and lower on separation-related behavior the more they had been able to play with other dogs. These findings have implications for matching between dogs' early and later home environments. Follow-up of dogs in this study could help to elucidate effects on guiding suitability and matching between dog and guide dog owner

Designing small multiple-target artificial RNAs

MicroRNAs (miRNAs) are naturally occurring small RNAs that regulate the expression of several genes. MiRNAs’ targeting rules are based on sequence complementarity between their mature products and targeted genes’ mRNAs. Based on our present understanding of those rules, we developed an algorithm to design artificial miRNAs to target simultaneously a set of predetermined genes. To validate in silico our algorithm, we tested different sets of genes known to be targeted by a single miRNA. The algorithm finds the seed of the corresponding miRNA among the solutions, which also include the seeds of new artificial miRNA sequences potentially capable of targeting these genes as well. We also validated the functionality of some artificial miRNAs designed to target simultaneously members of the E2F family. These artificial miRNAs reproduced the effects of E2Fs inhibition in both normal human fibroblasts and prostate cancer cells where they inhibited cell proliferation and induced cellular senescence. We conclude that the current miRNA targeting rules based on the seed sequence work to design multiple-target artificial miRNAs. This approach may find applications in both research and therapeutics

An RNA Transport System in Candida albicans Regulates Hyphal Morphology and Invasive Growth

Localization of specific mRNAs is an important mechanism through which cells achieve polarity and direct asymmetric growth. Based on a framework established in Saccharomyces cerevisiae, we describe a She3-dependent RNA transport system in Candida albicans, a fungal pathogen of humans that grows as both budding (yeast) and filamentous (hyphal and pseudohyphal) forms. We identify a set of 40 mRNAs that are selectively transported to the buds of yeast-form cells and to the tips of hyphae, and we show that many of the genes encoded by these mRNAs contribute to hyphal development, as does the transport system itself. Although the basic system of mRNA transport is conserved between S. cerevisiae and C. albicans, we find that the cargo mRNAs have diverged considerably, implying that specific mRNAs can easily move in and out of transport control over evolutionary timescales. The differences in mRNA cargos likely reflect the distinct selective pressures acting on the two species

Identification of Hammerhead Ribozymes in All Domains of Life Reveals Novel Structural Variations

Hammerhead ribozymes are small self-cleaving RNAs that promote strand scission by internal phosphoester transfer. Comparative sequence analysis was used to identify numerous additional representatives of this ribozyme class than were previously known, including the first representatives in fungi and archaea. Moreover, we have uncovered the first natural examples of “type II” hammerheads, and our findings reveal that this permuted form occurs in bacteria as frequently as type I and III architectures. We also identified a commonly occurring pseudoknot that forms a tertiary interaction critical for high-speed ribozyme activity. Genomic contexts of many hammerhead ribozymes indicate that they perform biological functions different from their known role in generating unit-length RNA transcripts of multimeric viroid and satellite virus genomes. In rare instances, nucleotide variation occurs at positions within the catalytic core that are otherwise strictly conserved, suggesting that core mutations are occasionally tolerated or preferred

Pilot survey of deep-water seagrasses using the Great Reef Census framework

A pilot study was established in 2021 to test the effectiveness of using the Great Reef Census (GRC) to collect broadscale survey data on deep-water marine macrophytes (seagrass and algae) and associated inter-reef habitats of the Great Barrier Reef World Heritage Area (GBRWHA). This report presents survey results from the 2021 field campaign and includes a review of how this approach can be used in future to effectively update 20-30 year old datasets and validate predictive models on seagrass distribution in the inter-reef lagoon. Overall, results provide a snapshot of deep-water seagrass and Halimeda algal bed distribution where GRC expeditions targeted more remote and logistically challenging regions of the GBR: Far North, Ribbon Reefs and Swain Reefs. We were able to deploy and record footage with the necessary camera equipment and methodology using three different vessel types and the personnel/participants on board: 1) the game fishing vessel MV Allure (Ribbon Reefs), 2) the superyacht MV Aroona (Far North), and 3) the long-range multi-purpose charter vessel MV Eastern Voyager (Swains). The opportunity provided the opportunity to educate participants in the importance of seagrasses and inter-reef habitat communities and was met with strong enthusiasm and desire to continue these efforts into the future. Inter-reef habitats >20m were surveyed using live and recorded CCTV camera systems to verify benthic macrophyte presence. Survey results are compared against probability models of seagrass presence. Geographic Information System(GIS) layers and associated metadata on seagrass and algae site information are available to inform research analysis and management advice. This resource will be incorporated into future iterations of the e-Atlas seagrass synthesis layers and available on request from TropWATER. Trial seagrass survey technique across at least 3 geographic areas along the length of the Great Barrier Reef with three different types of operations and participants (e.g. tourism operator, commercial operator, Traditional Owner ranger vessel) to allow for understanding of logistical operations In addition to deepwater survey trials, this project enabled the additional survey of greater than 315 reefs during GRC in 2021; far in excess of goals to add an additional 15 reefs as part of this pilot study’s objective