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The contribution of objective and perceived crime to neighbourhood socio-inequity in loneliness
No full textLoneliness tends to be more prevalent in socioeconomically disadvantaged neighbourhoods, yet few studies explore the environmental differences contributing to area-based inequity in loneliness. This study examined how perceived and objective crime contributed to differences in loneliness between advantaged and disadvantaged neighbourhoods. The study used cross-sectional data from 3749 individuals aged between 48 and 77 years, residing in 200 neighbourhoods in Brisbane, Australia. We found that participants in disadvantaged neighbourhoods reported higher levels of loneliness and perceived crime, and the most disadvantaged neighbourhoods also had highest prevalence of objective crime. However, while perceived and objective crime were positively correlated with loneliness, only perceived crime accounted for socio-economic inequity in loneliness. Consequently, perceived crime plays an important role in addressing loneliness in disadvantaged communities and requires equitable resourcing for multiple strategies that aim to decrease crime and increase perceived safety
Graphene/h-BN hybrid van der Waals structures with high strength and flexibility: A nanoindentation investigation
No full textTwo-dimensional nanomaterials, such as graphene and h-BN have been widely used as reinforcing fillers for polymer-based impact protection materials, phase change materials (PCM) or thermal interface materials (TIM) due to its exceptional high mechanical strength and high thermal conductivity. But the mechanical properties of graphene/h-BN (GBN) van der Waals (vdW) heterostructures remain largely unexplored. Herein we carry out intensive nanoindentation tests on GBN by using molecular dynamics simulations as well as finite element analysis to investigate its mechanical properties, fracture mechanisms as well as the effective manipulation techniques for force and deformation. Compared with its homogeneous counterparts (pure graphene or pure h-BN), the heterogeneous GBN possess excellent performance in resisting bending deformation in terms of the indentation load and depth. The size-dependent performance of GBN can be effectively manipulated by hydrogenation in the middle graphene and layer number, except the composition diffusion interface. This comprehensive study confirms that the high strength and high flexibility of GBN endow it with great potential in the applications of impact protection and thermal management in PCM and TIM
QARMA-FL: Quality-Aware Robust Model Aggregation for Mobile Crowdsourcing
No full textOver the past few years, the improved detection and processing features of Internet of Things (IoT) devices have opened the doors to several mobile crowdsourcing (MC) applications. Federated learning (FL) is being seen as an attractive framework to address the data privacy concerns of mobile users in the context of crowdsourcing. In FL on a crowdsourcing platform, constructing an effective deep neural network (DNN) is challenging. This is primarily because the quality of the global model depends on the local model quality, which can vary greatly due to differences in the computational resources, data quantity, and data quality provided by each worker. To address these challenges, we propose QARMA-FL: quality-aware robust model aggregation for FL in crowdsourcing applications, where we select the local model for aggregation based on its quality and performance. We also propose a model-quality-aware incentive mechanism to reward workers, based on their contribution to model training. Our model selection and incentive mechanism is capable of detecting free rider (FR) attacks, identifying workers who benefit from others' contributions without contributing themselves. Most existing evaluations of FL in MC studies are not based on the real-world FL scenarios. Therefore, we evaluate QARMA-FL alongside a baseline FL model in a quantity-skew, non-identically distributed (IID) data setup where different workers contribute varying amounts of data for model training. Our diverse experiments validated QARMA-FL's performance, demonstrating its ability to efficiently aggregate models in MC scenarios, reaching baseline results with a reduced worker participation by 40% to 60%
Cognitive Biases in Fact-Checking and Their Countermeasures: A Review
No full textThe increase of the amount of misinformation spread every day online is a huge threat to the society. Organizations and researchers are working to contrast this misinformation plague. In this setting, human assessors are indispensable to correctly identify, assess and/or revise the truthfulness of information items, i.e., to perform the fact-checking activity. Assessors, as humans, are subject to systematic errors that might interfere with their fact-checking activity. Among such errors, cognitive biases are those due to the limits of human cognition. Although biases help to minimize the cost of making mistakes, they skew assessments away from an objective perception of information. Cognitive biases, hence, are particularly frequent and critical, and can cause errors that have a huge potential impact as they propagate not only in the community, but also in the datasets used to train automatic and semi-automatic machine learning models to fight misinformation. In this work, we present a review of the cognitive biases which might occur during the fact-checking process. In more detail, inspired by PRISMA – a methodology used for systematic literature reviews – we manually derive a list of 221 cognitive biases that may affect human assessors. Then, we select the 39 biases that might manifest during the fact-checking process, we group them into categories, and we provide a description. Finally, we present a list of 11 countermeasures that can be adopted by researchers, practitioners, and organizations to limit the effect of the identified cognitive biases on the fact-checking activity
Subacromial contact after acromioplasty in the rotator cuff deficient shoulder
No full textSubacromial impingement (SAI) is associated with shoulder pain and dysfunction and is exacerbated by rotator cuff tears; however, the role of acromioplasty in mitigating subacromial contact in the rotator cuff deficient shoulder remains debated. This study aimed to quantify the influence of isolated and combined tears involving the supraspinatus on subacromial contact during abduction; and second, to evaluate the influence of acromioplasty on joint space size and subacromial contact under these pathological conditions. Eight fresh-frozen human cadaveric upper limbs were mounted to a computer-controlled testing apparatus that simulated joint motion by simulated force application. Shoulder abduction was performed while three-dimensional joint kinematics was measured using an optoelectronic system, and subacromial contact evaluated using a digital pressure sensor secured to the inferior acromion. Testing was performed after an isolated tear to the supraspinatus, as well as tears involving the subscapularis and infraspinatus-teres minor, both before and after acromioplasty. Rotator cuff tears significantly increased peak subacromial pressure (p < 0.001), average subacromial pressure (p = 0.001), and contact force (p = 0.034) relative to those in the intact shoulder. Following acromioplasty, significantly lower peak subacromial contact pressure, force and area were observed for all rotator cuff tears involving the supraspinatus at 30° of abduction (p < 0.05). Acromioplasty predominantly reduces acromion thickness anteriorly thereby reducing subacromial contact in the rotator cuff deficient shoulder, particularly in early to mid-abduction where superior glenohumeral joint shear force potential is large. These findings provide a biomechanical basis for acromioplasty as an intervention for SAI syndrome and as an adjunct to rotator cuff repairs
A creative ecological approach to supporting young people with mental health challenges in schools
No full textHolistic and ecological approaches to mental health support have been identified by many as best-practice approaches for creating and sustaining well-being. Those who experience mental health challenges including, for example, Borderline Personality Disorder (BPD), often struggle to find adequate, sustainable and ongoing care from clinical settings, and recent research shows that additional strategies such as peer support programs, arts approaches, and holistic school-based collaboration work effectively. More generally, the mainstream population continues to suffer from outdated, overly medicalised and frequently inaccurate notions of the experience of poor mental health and the effective support of those who suffer, and peer- and school-integrated approaches go some way toward better education about mental ill-health. This article uses a creative ecologies model (Harris, 2016) to help schools implement student- and family-led support programs for students experiencing mental health challenges in school settings
Ru/ZrO2-based catalysts for CO2 hydrogenation and investigation on reaction mechanism
No full textThe rising concern about extensive depletion of fossil fuels and resulting high CO2 concentration urges the shift into the use of renewable fuels. Under this critical circumstance, CO2 utilisation presents outstanding advantages to mitigate the record-high CO2 concentration in the atmosphere. One approach of CO2 utilisation is CO2 hydrogenation, which CO2 and H2 react over a catalyst to produce carbon-neutral fuels like methane (CH4). Thermal-catalytic CO2 hydrogenation into hydrocarbons have been widely investigated as one promising CO2 hydrogenation strategy and potentially can be adapted to the existing industrial sectors. However, their cost-effective industrial applications will highly depend on the design of efficient catalysts that stably operated at high temperature and elevated pressure, whilst providing high conversion rate and selectivity. Commercial Ni-supported catalysts for large- scale CH4 production are restrained due to the deactivation by coke formation. Ruthenium (Ru) is known for its durability but bares high cost. Controlling Ru loading and introducing other metal promoters has been studied intensively in literature. To achieve desirable catalytic performance, it’s critical to understand the synergy amongst all the catalyst components and disclose the structure-activity relationship for optimising the catalyst systems. In this study, Ru was selected as active metals for H2 dissociation and spillover, while ZrO2 was selected as support materials for providing CO2 adsorbing sites and building up the strong metal-support interaction (SMSI). The structure modifications of Ru/ZrO2-based catalysts in this work include doping ZrO2, ZrO2 phase control and bimetallic RuGa supported ZrO2.
For dopant study, Ru/SnxZr1-xO2 catalysts were prepared using co-precipitated Sn-doped ZrO2. Ru/ZrO2 and Ru/Sn0.01Zr0.99O2 both comprised tetragonal (t-) and monoclinic (m-) ZrO2 nanoparticles decorated by RuO2·H2O clusters. Ru/Sn0.2Zr0.8O2 exhibited similar textural properties and metal speciation, however, X-ray diffraction evidenced new crystalline phases wherein Sn atoms substituted for Zr. Operando XRD evidenced minimal of ZrO2 and Sn-doped ZrO2 phases, despite which 20 atom% Sn switched product selectivity from 99 % CH4 for Ru/ZrO2 to 67 % CO, due to increased support CO2 adsorption capacity/strength. Operando diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) identify linear surface CO* as a catalytic spectator with (bi)carbonate a precursor to reactive HCOO*/carboxylate intermediates to methane. Sn0.2Zr0.8O2 promotes CO2/(bi)carbonate/formate decomposition, favouring a reverse water gas shift pathway.
For support phase study, monoclinic (m-) and tetragonal (t-) ZrO2 supports were prepared via hydrothermal method with subsequent Ru supported at different concentrations (0.5, 1.1 and 1.7 wt%) using incipient wetness impregnation (IWI) method. Ru species demonstrate different dispersions and oxidation states on m- and t-ZrO2 surfaces. High-resolution transmission electron microscopy (HRTEM) evidence that Ru exhibit similar atomic dispersion on m-ZrO2, while Ru cluster sizes increase on t-ZrO2 as Ru concentration increasing. X-ray photoelectron spectroscopy (XPS) demonstrates the lower binding energy of RuO2 species on t-ZrO2, indicating more reducible Ru species on t-ZrO2 than on m-ZrO2. Operando DRIFTS study confirm the formate species are key intermediates for CH4 production over Ru/m-ZrO2 catalysts, while carboxylate species are key intermediates for CH4 formation over Ru/t-ZrO2. And linear surface CO* as a catalytic spectator are easier to form up on smaller Ru clusters as more CO* species are observed on Ru/m-ZrO2 than on Ru/t-ZrO2 samples.
For bimetallic study, RuGa/ZrO2 and Ru/ZrO2were prepared using precipitation with Ga/ZrO2 as control samples. XPS shows that Ga addition increases Ru0/(Ru0 + Ru(Ⅳ)) ratio and improves the Ru reducibility induced by electron transfer between Ru and Ga species. For sample RuGa(4:1)/ZrO2, small amount of Ga improves Ru dispersion and the CO2 conversion with high CH4 selectivity. For sample RuGa(1:5)/ZrO2, higher amount of Ga demonstrates more efficient electron transfer and increases the strong basic sites in samples. Operando DRIFTS-MS confirms that more formate species form during CO2 hydrogenation for RuGa(4:1)/ZrO2, thereby enhancing CH4 production. However, RuGa(1:5)/ZrO2 sample exhibits product selectivity shifts to CO formation. Operando DRIFTS-MS reveals that higher Ga concentration inhibits the formation of formate species and promote the decomposition of carboxylate species into CO.
This work has contributed to the catalyst engineering for CO2 hydrogenation. The understanding of the obtained materials provides the insights to establish the structure-activity relationship for optimising CO2 reduction catalysts and can lead to opportunities of carbon- neutral fuel production.</p
Potential of bacterial cellulose for sustainable fashion and textile applications: A review
No full textThe fashion and textile manufacturing sectors are increasingly focusing on innovative raw materials that are renewable and biodegradable. Such materials not only mitigate environmental impacts but also prevent resource depletion. Bacterial cellulose (BC) has emerged as a prime candidate, derivable from a variety of natural ingredients such as tea and coffee in addition to a sugar source in presence of the bacterial microorganisms. Numerous studies have established the potential of BC in future fashion, and some brands have already started to utilise BC as a sustainable raw material. The applications of BC ranges from basic clothing and accessories to wearable electronics. This paper discusses the scope of BC in fashion and textiles, positioning it as a sustainable alternative to conventional materials. We present a comprehensive scoping review, covering the unique properties of BC, the factors influencing its production, and its applications in textile, clothing, and footwear over the past decade. The advantages of BC in fashion are manifold: zero-waste manufacturing, reliance on renewable sources, diminished environmental pollution, and biodegradability. Furthermore, the use of BC aligns with United Nations Sustainable Development Goals 6, 7, 12, 13 and 15. However, there exist challenges pertaining to production costs, scalability, and quality, in addition to the imperative of harnessing food waste streams instead of contending for human food resources. Addressing these challenges is vital to cement BC’s position as a pivotal sustainable material in future fashion.</p
The Determination of Crystal Structure by X-ray Scattering Correlation Analysis
No full textThe molecular structure of materials, chemicals and bio-particles form the basis for how we understand chemical and physical interactions in the universe. The atomic structure of a molecule ultimately informs the properties and function of a material or compound. This is particularly the case for biologically active molecules, such as proteins [1]. Proteins perform many functions in nature, such as catalysis [2], cell signalling [3] or transporting nutrients [3–5]. In rational drug design, pharmaceuticals are designed to target these metabolic processes [6, 7]. Compounds are optimised based on their structure to improve binding and specificity to drug targets [8].
The most widely used method of structure determination for proteins is crystallography. In crystallography experiments, the diffraction of X-rays through a crystal is measured through all orientations of the crystal. The diffraction intensity is proportional to structure factors in the crystal structure [9] and is used to reconstruct the electron density in the crystal. Crystallography is limited by two interconnected factors. The first issue is that protein crystals must be large enough to withstand X-ray damage during rotation in the beam. X-ray damage to the crystal can cause changes to the structure within the crystal, and smaller crystals are more susceptible to X-ray damage since the X-ray dose is spread over a smaller volume [10,11]. Smaller crystals also scatter more weakly than larger crystals, because there are fewer repeating layers to enhance the diffraction signal. The requirement for large single crystals also limits what proteins can be investigated with this method. Membrane proteins are a class of protein that are situated on the cell membrane and contain hydrophilic and hydrophobic regions on the protein surface.
The opposing interaction between these surfaces creates challenges in growing large crystals of membrane proteins for crystallography experiments [12].
Serial crystallography experiments, a modern iteration of traditional crystallography methods, can be used to study smaller crystals. In these experiments, a series of crystals is sequentially streamed into the X-ray beam, and diffraction from many individual crystals in random orientations is collected over time. Serial crystallography experiments are typically conducted at X-ray Free Electron Lasers (XFELs), which can study much smaller crystals than a typical synchrotron source. The femtosecond exposure of XFEL sources allows for diffraction from the crystals to be collected before their destruction [13]. The brilliance of the XFEL source, which is to the order of a billion times brighter than a typical synchrotron source [14], also means that smaller crystals can be used, which facilitates studying crystals that are challenging to grow into large single crystals. However, multi-crystal diffraction patterns are a problem within serial crystallography experiments. These occur when more than one crystal domain contributes to the diffraction pattern. In serial crystallography, this occurs when more then one crystal is imaged in the stream. In traditional crystallography, multi-crystal diffraction patterns can occur due to mosaicity in the crystal [15, 16].
Powder diffraction is another possible method of structure determination for powdered crystalline samples. Although powder diffraction is a standard tool for structure determination of small chemical crystals [17], it is rarely applied to protein crystals [18]. Protein crystal unit cells are much larger than small chemical crystals, and so diffraction peaks can overlap within the diffraction pattern. Powder diffraction also requires significantly more crystals in a powder form.
This indicates a fundamental gap within protein structure determination. Serial crystallography experiments are ensemble measurements that necessitate many single diffracting crystals, while powder experiments require many thousands of crystals. Between these opposing requirements is X-ray scattering correlation analysis (XSCA). XSCA is a diffraction analysis technique that measures the diffraction from multiple scattering objects simultaneously [19], in order to calculate a scattering correlation function. In an XSCA experiment, there are no strict requirements regarding the number of scattering objects within a single diffraction pattern. However, the scattering objects must be identical, and have a uniform orientation distribution that samples all the orientations of the object. The use of XSCA for recovering single particle structure has been demonstrated for a variety of single particle structures [20–23].
The pair angle distribution function (PADF) is a quantitative measure of the distributions of two-, three-, and four-body atomic arrangements in a structure, and is calculated after performing XSCA [24]. It has been used to study the local structures in amorphous and semi-crystalline phases, such as graphitic samples [25] and liquid crystals [26] but has not yet been applied to protein crystal structures. The PADF has the potential to highlight elements of structure unique to proteins, such as alpha helices and beta sheets, and is sensitive to structural changes that would be observed when a protein changes conformation.
Currently, there is no way to extract protein crystal structure factors using XSCA. Another common method of structure determination in X-ray science is phase recovery with iterative projection algorithms [27, 28]. XSCA has previously been used with iterative projection algorithms for single particle structure recovery [29,30], but is yet to be applied for crystal structure determination. By applying XSCA on protein crystal diffraction, it may be possible to recover the single crystal structure factors from multi-crystal diffraction patterns observed in serial crystallography experiments.
In this thesis, I will investigate how XSCA can be used in determining protein crystal structure. This will involve determining how elements of protein structure affect components of scattering correlation functions and the PADF of crystal structures. This could lead to identifying fingerprint features in the correlation functions that inform elements of protein structure. I will also develop a novel method of extracting the reciprocal space intensity function from the scattering correlation function of a crystal. Once the intensity function has been recovered from the correlation function, established methods of crystal structure determination observed in crystallography can be used to find the atomic structure of the proteins in the crystal. Finally, I will also investigate the feasibility of XSCA experiments on crystals, and determine how many crystal diffraction patterns are required to complete the structural analysis.</p
Internalised deficit perspectives: positionality in culturally responsive pedagogical frameworks
No full textBy showing that deficit thinking can manifest in an internalised sense among historically minoritised students, this paper examines the significance of ‘positionality’ in (re)conceptualising culturally responsive pedagogies (CRPs). Drawing from a study that explored the lived experiences of students participating in a culturally and linguistically diverse context, I demonstrate that whilst some students’ dispositions towards their home cultures and languages align with the anti-deficit and anti-racist agendas of CRPs, some dispositions present a counter-narrative and can be supportive of the status quo. I refer to these dispositions as ‘internalised deficit thinking or perspectives’. To capture this concept and, in a more general sense, the diverse subjectivities students used to navigate Westernised schooling arrangements, this paper advances the notion of positionality. Bringing ‘positionality’ into conversation with CRPs means confronting the relations of power, embodied by students of diverse backgrounds, in fostering socially just educational experiences.</p