6,633 research outputs found
Recommended from our members
Effects of urbanisation and landscape heterogeneity mediated by feeding guild and body size in a community of coprophilous beetles
Although the impacts of urbanisation on biodiversity are well studied, the precise response of some invertebrate groups remains poorly known. Dung-associated beetles are little studied in an urban context, especially in temperate regions. We considered how landscape heterogeneity, assessed at three spatial scales (250, 500 and 1000 metre radius), mediates the community composition of coprophilous beetles on a broad urban gradient. Beetles were sampled using simple dung-baited traps, placed at 48 sites stratified across three distance bands around a large urban centre in England. The most urban sites hosted the lowest abundance of saprophagous beetles, with a lower mean body length relative to the least urban sites. Predicted overall species richness and the richness of saprophagous species were also lowest at the most urban sites. Ordination analyses followed by variation partitioning revealed that landscape heterogeneity across the urban gradient explained a small but significant proportion of community composition. Heterogeneity data for a 500-metre radius around each site provided the best fit with beetle community data. Larger saprophagous species were associated with lower amounts of manmade surface and improved grassland. Some individual species, particularly predators, appeared to be positively associated with urban or urban fringe sites. This study is probably the first to examine the response of the whole coprophilous beetle community to urbanisation. Our results suggest that the response of this community to urbanisation matches expectations based on other taxonomic groups, whilst emphasising the complex nature of this response, with some smaller-bodied species potentially benefitting from urbanisation
The volume and source of cyberabuse influences victim blame and perceptions of attractiveness
Cyberabuse is an escalating problem in society, as opportunities for abuse to occur in online public domains increase. Such acts are often defined by the frequency of abuse, and in many cases multiple individuals play a part in the abuse. Although consequences of such acts are often severe, there is typically little public sympathy/support for victims. To better understand perceptions of victims of abusive online acts, we manipulated the Volume (low, high) and Source (same-source, multi-source) of abusive posts in artificially-manipulated Facebook timelines of four fictitious ‘victims’. One hundred and sixty-four participants [United Kingdom-based; aged 18–59] rated ‘victims’ on measures of direct victim blame (DVB) and perceived social-, physical- and task-attractiveness. Results revealed significant Volume × Source interactions on DVB and social-attractiveness ratings. Few abusive posts authored by a single source yielded higher DVB and lower social-attractiveness ratings. Strong correlations between attractiveness and DVB were observed. We propose that our results could be due to an observer desensitization effect, or that participants interpreted the posts as indicative of friendly ‘teasing’ or ‘banter’ within an established social relationship, helping to explain why victims of online abuse often receive little sympathy or support
Recommended from our members
The properties of Msh2-Msh6 ATP binding mutants suggest a signal amplification mechanism in DNA mismatch repair.
DNA mismatch repair (MMR) corrects mispaired DNA bases and small insertion/deletion loops generated by DNA replication errors. After binding a mispair, the eukaryotic mispair recognition complex Msh2-Msh6 binds ATP in both of its nucleotide-binding sites, which induces a conformational change resulting in the formation of an Msh2-Msh6 sliding clamp that releases from the mispair and slides freely along the DNA. However, the roles that Msh2-Msh6 sliding clamps play in MMR remain poorly understood. Here, using Saccharomyces cerevisiae, we created Msh2 and Msh6 Walker A nucleotide-binding site mutants that have defects in ATP binding in one or both nucleotide-binding sites of the Msh2-Msh6 heterodimer. We found that these mutations cause a complete MMR defect in vivo The mutant Msh2-Msh6 complexes exhibited normal mispair recognition and were proficient at recruiting the MMR endonuclease Mlh1-Pms1 to mispaired DNA. At physiological (2.5 mm) ATP concentration, the mutant complexes displayed modest partial defects in supporting MMR in reconstituted Mlh1-Pms1-independent and Mlh1-Pms1-dependent MMR reactions in vitro and in activation of the Mlh1-Pms1 endonuclease and showed a more severe defect at low (0.1 mm) ATP concentration. In contrast, five of the mutants were completely defective and one was mostly defective for sliding clamp formation at high and low ATP concentrations. These findings suggest that mispair-dependent sliding clamp formation triggers binding of additional Msh2-Msh6 complexes and that further recruitment of additional downstream MMR proteins is required for signal amplification of mispair binding during MMR
RISKY BUSINESS: AN ANALYTICAL APPROACH TO SERVICES SUPPLY CHAIN RISK MANAGEMENT
Cyber threats, economic upheavals, and environmental disasters threaten global supply chains. These vulnerabilities impact the readiness of U.S. forces and their capacity to defend the nation. Consumers and the government need a framework for assessing vulnerabilities and establishing effective supply chains. MITRE’s System of Trust (SoT) serves as a framework to measure trustworthiness and identify risk factors affecting their supply chain security. The SoT develops a taxonomy of risk factors, defines risk measures attributable to those risk factors, and creates a framework for organizations to objectively quantify supply chain risk. Our study validates the services risk factors and identifies techniques and best practices to mitigate risk unique for services. Our research questions are: What are the primary indicators of supply chain risk, and which are unique to Department of Defense services? Furthermore, what are the best practices for preventing, mitigating, and responding to service-specific supply chain risks? This research draws on qualitative interview data to obtain insight into the services aspect of supply chains, systematically evaluate MITRE’s risk factors and risk measures, and identify gaps in available data. Our research results in a Services Supply Chain Risk Management Framework that managers should use to evaluate and mitigate risks within their supply chains.Captain, United States Air ForceCaptain, United States Air ForceApproved for public release. Distribution is unlimited
Assessing the effect of dynamics on the closed-loop protein-folding hypothesis
The closed-loop (loop-n-lock) hypothesis of protein folding suggests that loops of about 25 residues, closed through interactions between the loop ends (locks), play an important role in protein structure. Coarse-grain elastic network simulations, and examination of loop lengths in a diverse set of proteins, each supports a bias towards loops of close to 25 residues in length between residues of high stability. Previous studies have established a correlation between total contact distance (TCD), a metric of sequence distances between contacting residues (cf. contact order), and the log-folding rate of a protein. In a set of 43 proteins, we identify an improved correlation (
r
2
= 0.76), when the metric is restricted to residues contacting the locks, compared to the equivalent result when all residues are considered (
r
2
= 0.65). This provides qualified support for the hypothesis, albeit with an increased emphasis upon the importance of a much larger set of residues surrounding the locks. Evidence of a similar-sized protein core/extended nucleus (with significant overlap) was obtained from TCD calculations in which residues were successively eliminated according to their hydrophobicity and connectivity, and from molecular dynamics simulations. Our results suggest that while folding is determined by a subset of residues that can be predicted by application of the closed-loop hypothesis, the original hypothesis is too simplistic; efficient protein folding is dependent on a considerably larger subset of residues than those involved in lock formation.
</jats:p
Recommended from our members
New distributional record of Anthrenus dorsatus Mulsant & Rey, 1868 (Coleoptera, Dermestidae) on the island of Mallorca, Spain
The carpet beetle Anthrenus dorsatus has previously been recorded from North Africa and Malta. During a recent visit to the island of Mallorca several Anthrenus species were collected which included a number of Anthrenus dorsatusspecimens. This record adds a new species both to the island of Mallorca and to the Spanish checklist. These records extend our knowledge of the distribution of A. dorsatus and provide more evidence of range expansion in the pimpinel-lae species group across Europe, possibly because of global climate change
The percutaneous absorption of soman in a damaged skin porcine model and the evaluation of WoundStatâ„¢ as a topical decontaminant
PURPOSE: The aim of this study was to evaluate a candidate haemostat (WoundStat™), down-selected from previous in vitro studies, for efficacy as a potential skin decontaminant against the chemical warfare agent pinacoyl methylfluorophosphonate (Soman, GD) using an in vivo pig model. MATERIALS AND METHODS: An area of approximately 3 cm2 was dermatomed from the dorsal ear skin to a nominal depth of 100 µm. A discrete droplet of 14C-GD (300 µg kg-1) was applied directly onto the surface of the damaged skin at the centre of the dosing site. Animals assigned to the treatment group were given a 2 g application of WoundStat™ 30 s after GD challenge. The decontamination efficacy of WoundStat™ against GD was measured by the direct quantification of the distribution of 14C-GD, as well as routine determination of whole blood cholinesterase and physiological measurements. RESULTS: WoundStat™ sequestered approximately 70% of the applied 14C-GD. Internal radiolabel recovery from treated animals was approximately 1% of the initially applied dose. Whole blood cholinesterase levels decreased to less than 10% of the original value by 15 min post WoundStat™ treatment and gradually decreased until the onset of apnoea or until euthanasia. All treated animals showed signs of GD intoxication that could be grouped into early (mastication, fasciculations and tremor), intermediate (miosis, salivation and nasal secretions) and late onset (lacrimation, body spasm and apnoea) effects. Two of the six WoundStat™ treated animals survived the study duration. CONCLUSIONS: The current study has shown that the use of WoundStat™ as a decontaminant on damaged pig ear skin was unable to fully protect against GD toxicity. Importantly, the findings indicate that the use of WoundStat™ in GD contaminated wounds would not exacerbate GD toxicity. These data suggest that absorbent haemostatic products may offer some limited functionality as wound decontaminants.Peer reviewedFinal Accepted Versio
Atypical chemokine receptor ACKR2 controls branching morphogenesis in the developing mammary gland
Macrophages are important regulators of branching morphogenesis during development and postnatally in the mammary gland. Regulation of macrophage dynamics during these processes can therefore have a profound impact on development. We demonstrate here that the developing mammary gland expresses high levels of inflammatory CC-chemokines, which are essential in vivo regulators of macrophage migration. We further demonstrate that the atypical chemokine receptor ACKR2, which scavenges inflammatory CC-chemokines, is differentially expressed during mammary gland development. We have previously shown that ACKR2 regulates macrophage dynamics during lymphatic vessel development. Here, we extend these observations to reveal a novel role for ACKR2 in regulating the postnatal development of the mammary gland. Specifically, we show that Ackr2−/− mice display precocious mammary gland development. This is associated with increased macrophage recruitment to the developing gland and increased density of the ductal epithelial network. These data demonstrate that ACKR2 is an important regulator of branching morphogenesis in diverse biological contexts and provide the first evidence of a role for chemokines and their receptors in postnatal development processes
- …