557 research outputs found
The evolution of conifolds
We simulate the gravitational dynamics of the conifold geometries (resolved
and deformed) involved in the description of certain compact spacetimes. As the
cycles of the conifold collapse towards a singular geometry we find that a
horizon develops, shielding the external spacetime from the curvature
singularity of the newly formed black hole. The structure of the black hole is
examined for a range of initial conditions, and we find a candidate black-hole
solution for the final state of the collapse.Comment: 22 pages, 6 figure
Factors Affecting Shark Detection from Drone Patrols in Southeast Queensland, Eastern Australia
Drones enable the monitoring for sharks in real-time, enhancing the safety of ocean users with minimal impact on marine life. Yet, the effectiveness of drones for detecting sharks (especially potentially dangerous sharks; i.e., white shark, tiger shark, bull shark) has not yet been tested at Queensland beaches. To determine effectiveness, it is necessary to understand how environmental and operational factors affect the ability of drones to detect sharks. To assess this, we utilised data from the Queensland SharkSmart drone trial, which operated at five southeast Queensland beaches for 12 months in 2020–2021. The trial conducted 3369 flights, covering 1348 km and sighting 174 sharks (48 of which were >2 m in length). Of these, eight bull sharks and one white shark were detected, leading to four beach evacuations. The shark sighting rate was 3% when averaged across all beaches, with North Stradbroke Island (NSI) having the highest sighting rate (17.9%) and Coolum North the lowest (0%). Drone pilots were able to differentiate between key shark species, including white, bull and whaler sharks, and estimate total length of the sharks. Statistical analysis indicated that location, the sighting of other fauna, season and flight number (proxy for time of day) influenced the probability of sighting shark
EFFECTS OF SIX WEEKS OF TRAINING ON INTERSEGMENTAL COORDINATION IN THE ROWING STROKE OF NOVICE INTERCOLLEGIATE ROWERS
The purpose of the study was to examine changes in coordination during the rowing stroke after 1 and 6 weeks of practice. Initially 11 healthy, females who had elected to join a college rowing program volunteered to participate in both testing sessions: Only 3 participants were still on the novice team at wk 6, thus N=3. Participants were video taped on a land ergometer in 2D using the Peak Motion Measurement System. SPC was assessed between adjacent 2-segment combinations of the T-S (trunk-shoulder), K-T (knee-trunk), and S-E (shoulder-elbow) to quantify intersegmental coordination. Mean changes in T-S (78.7% v 74.6 %), K-T (66.5% v 102.9%) and S-E (88.2% v 71.3%) showed that the rowing stroke is primarily a simultaneous pattern. However. individual SPC (shared positive contribution) changes varied indicating that 6 wks is not a long enough for coordination to develop in novice rowers
Vol. 2 Ch. 4 Material Choice and Interaction on Brown\u27s Bottom
https://ideaexchange.uakron.edu/encountering_hopewell/1014/thumbnail.jp
\u3ci\u3eIshtarella thailandica\u3c/i\u3e Martens, new genus, new species (Hymenoptera: Braconidae: Aphidiinae) of aphid parasitoid from Thailand, with a country checklist of Aphidiinae
Ishtarella Martens new genus (Hymenoptera: Braconidae: Aphidiinae) and I. thailandica Martens new species are described and illustrated from Doi Phu Kha National Park, Nan Province, Thailand. The genus is assigned to the tribe Aphidiini, subtribe Trioxina. Based on morphology, Ishtarella appears most closely related to Binodoxys Mackauer. An updated checklist of the aphidiine fauna of Thailand, based on published records, is presented.
Parasitoid wasps in the subfamily Aphidiinae (Hymenoptera: Braconidae) comprise about 60 genera and more than 650 species worldwide (Yu et al. 2016). The Aphidiinae of Thailand were all but unknown prior to a ThaiÂland Inventory Group for Entomological Research (TIGER) project from 2006–2009 (StarĂ˝ et al. 2008). As part of the TIGER project the Thai aphidiine fauna was surveyed using Malaise and pan traps; 20 species collectively representing 15 genera were reported from mixed deciduous or pine forests from 230 m to 2500 m above sea level (StarĂ˝ et al. 2008, 2010a, 2010b). Although there are no identification keys to the Thai Aphidiinae, genus-level identifications can be made using the keys presented in StarĂ˝ and Schlinger (1967), StarĂ˝ and Ghosh (1983), Raychaudhuri (1990), and Chen and Shi (2001).
The new genus described herein is assigned to the tribe Aphidiini, subtribe Trioxina. Females of most genera in this subtribe possess an elongate and curved ovipositor sheath and ovipositor. Additionally, females of some genera, like Binodoxys Mackauer and Trioxys Haliday, possess distinctive hypopygial prongs that are used to hold and restrain the aphid host during oviposition (Völkl and Mackauer 2000)
Ascaroside Expression in Caenorhabditis elegans Is Strongly Dependent on Diet and Developmental Stage
Background:
The ascarosides form a family of small molecules that have been isolated from cultures of the nematode Caenorhabditis elegans. They are often referred to as “dauer pheromones” because most of them induce formation of long-lived and highly stress resistant dauer larvae. More recent studies have shown that ascarosides serve additional functions as social signals and mating pheromones. Thus, ascarosides have multiple functions. Until now, it has been generally assumed that ascarosides are constitutively expressed during nematode development.
Methodology/Principal Findings:
Cultures of C. elegans were developmentally synchronized on controlled diets. Ascarosides released into the media, as well as stored internally, were quantified by LC/MS. We found that ascaroside biosynthesis and release were strongly dependent on developmental stage and diet. The male attracting pheromone was verified to be a blend of at least four ascarosides, and peak production of the two most potent mating pheromone components, ascr#3 and asc#8 immediately preceded or coincided with the temporal window for mating. The concentration of ascr#2 increased under starvation conditions and peaked during dauer formation, strongly supporting ascr#2 as the main population density signal (dauer pheromone). After dauer formation, ascaroside production largely ceased and dauer larvae did not release any ascarosides. These findings show that both total ascaroside production and the relative proportions of individual ascarosides strongly correlate with these compounds' stage-specific biological functions.
Conclusions/Significance:
Ascaroside expression changes with development and environmental conditions. This is consistent with multiple functions of these signaling molecules. Knowledge of such differential regulation will make it possible to associate ascaroside production to gene expression profiles (transcript, protein or enzyme activity) and help to determine genetic pathways that control ascaroside biosynthesis. In conjunction with findings from previous studies, our results show that the pheromone system of C. elegans mimics that of insects in many ways, suggesting that pheromone signaling in C. elegans may exhibit functional homology also at the sensory level. In addition, our results provide a strong foundation for future behavioral modeling studies
Queensland SharkSmart Drone Trial Final Report
Remotely Piloted Aircraft Systems, commonly called drones, provide a high-definition aerial view of a wide expanse of ocean, allowing the detection of potentially dangerous sharks in real-time, whilst having a negligible impact on the environment and non-target species. In addition, they are capable of spotting a range of marine hazards and can assist in beach rescue operations, thus providing numerous safety benefits for water users. The beaches of South-East Queensland (SEQ) have relatively good water clarity and a high level of visitation, making them an ideal location to test drones for detecting sharks and improving the safety of water users (Cardno, 2019). North Queensland beaches typically have lower water clarity, although it is important to test drones under these conditions to assess whether they can be effective at detecting sharks.
The Queensland SharkSmart drone trial commenced on 19 September 2020, as a partnership between the Queensland Government Department of Agriculture and Fisheries (DAF) and Surf Life Saving Queensland (SLSQ). The trial was part of the Queensland Government’s commitment to research and trialling alternatives to traditional shark control measures. Drones were operated at two beaches on the Sunshine Coast (Alexandra Headland and Coolum North), two beaches on the Gold Coast (Southport Main Beach and Burleigh Beach) and one beach on North Stradbroke Island (NSI; Ocean beach) between 19 September 2020 and 4 October 2021. Additionally, to assess the effectiveness of drones at detecting sharks under the different environmental conditions found at North Queensland (NQ) beaches, drones were operated at Palm Cove, Cairns and Alma Bay, Magnetic Island, from 26 June 2021 to 31 October 2021. Drones were operated on weekends, public holidays and school holidays by SLSQ pilots, with two flights per hour from approximately 8am until midday. Flights lasted 15 - 20 minutes and followed a 400 m transect behind the surf break. All footage was collected in 4K and securely archived for later analysis with key operational and environmental data collected for every flight. When a shark was sighted, the drone pilot lowered the aircraft to determine the species and size while estimating distance of the animal from water users. Data analysis quantified the numbers of sharks sighted at each beach and the rate of sightings as a percentage across the whole trial from 19 September 2020 to 31 October 2021. Generalised Linear Mixed Models (GLMMs) were applied to quantify the influence of environmental and operational factors on the sightability (probability of a shark being sighted) of sharks. The movement tracks of sharks were mapped to analyse their behaviour and identify if there was clustering of movements in certain areas. Sighting rates from drones were also compared with shark catch in adjacent nets and drumlines deployed as part of the Queensland Shark Control Program (SCP)
Assessment of patient-derived tumour xenografts (PDXs) as a discovery tool for cancer epigenomics
Background: The use of tumour xenografts is a well-established research tool in cancer genomics but has not yet
been comprehensively evaluated for cancer epigenomics.
Methods: In this study, we assessed the suitability of patient-derived tumour xenografts (PDXs) for methylome analysis
using Infinium 450 K Beadchips and MeDIP-seq.
Results: Controlled for confounding host (mouse) sequences, comparison of primary PDXs and matching patient
tumours in a rare (osteosarcoma) and common (colon) cancer revealed that an average 2.7% of the assayed CpG sites
undergo major (Δβ ≥ 0.51) methylation changes in a cancer-specific manner as a result of the xenografting procedure.
No significant subsequent methylation changes were observed after a second round of xenografting between primary
and secondary PDXs. Based on computational simulation using publically available methylation data, we additionally
show that future studies comparing two groups of PDXs should use 15 or more samples in each group to minimise
the impact of xenografting-associated changes in methylation on comparison results.
Conclusions: Our results from rare and common cancers indicate that PDXs are a suitable discovery tool for cancer
epigenomics and we provide guidance on how to overcome the observed limitations
Assessment of RainDrop BS-seq as a method for large-scale, targeted bisulfite sequencing.
We present a systematic assessment of RainDrop BS-seq, a novel method for large-scale, targeted bisulfite sequencing using microdroplet-based PCR amplification coupled with next-generation sequencing. We compared DNA methylation levels at 498 target loci (1001 PCR amplicons) in human whole blood, osteosarcoma cells and an archived tumor tissue sample. We assessed the ability of RainDrop BS-seq to accurately measure DNA methylation over a range of DNA quantities (from 10 to 1500 ng), both with and without whole-genome amplification (WGA) following bisulfite conversion. DNA methylation profiles generated using at least 100 ng correlated well (median R = 0.92) with those generated on Illumina Infinium HumanMethylation450 BeadChips, currently the platform of choice for epigenome-wide association studies (EWAS). WGA allowed for testing of samples with a starting DNA amount of 10 and 50 ng, although a reduced correlation was observed (median R = 0.79). We conclude that RainDrop BS-seq is suitable for measuring DNA methylation levels using nanogram quantities of DNA, and can be used to study candidate epigenetic biomarker loci in an accurate and high-throughput manner, paving the way for its application to routine clinical diagnostics
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