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Measurement of top-quark pair production in association with charm quarks in proton–proton collisions at √s = 13 TeV with the ATLAS detector
Get PDFInclusive cross-sections for top-quark pair production in association with charm quarks are measured with proton–proton collision data at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 140 fb−1, collected with the ATLAS experiment at the LHC between 2015 and 2018. The measurements are performed by requiring one or two charged leptons (electrons and muons), two b-tagged jets, and at least one additional jet in the final state. A custom flavor-tagging algorithm is employed for the simultaneous identification of b-jets and c-jets. In a fiducial phase space that replicates the acceptance of the ATLAS detector, the cross-sections for tt¯+≥2c and tt¯+1c production are measured to be 1.28−0.24+0.27pb and 6.4−0.9+1.0pb, respectively. The measurements are primarily limited by uncertainties in the modeling of inclusive tt¯ and tt¯+bb¯ production, in the calibration of the flavor-tagging algorithm, and by data statistics. Cross-section predictions from various tt¯ simulations are largely consistent with the measured cross-section values, though all underpredict the observed values by 0.5 to 2.0 standard deviations. In a phase-space volume without requirements on the tt¯ decay products and the jet multiplicity, the cross-section ratios of tt¯+≥2c and tt¯+1c to total tt¯+jets production are determined to be (1.23±0.25)% and (8.8±1.3)%
Certifying Bounds Propagation for Integer Multiplication Constraints
Get PDFA constraint programming (CP) solver that implements proof logging will output a machine-checkable certificate of correctness alongside any result it obtains. This is useful for trusting claims of unsatisfiability or optimality, as well as for debugging and auditing solver implementations. Proofs can be constructed by having the solver log justifications for each inference it makes, and previous work has shown that many standard CP reasoning techniques can be efficiently justified using a pseudo-Boolean (PB) proof format. This paper extends PB justifications to propagators enforcing bounds consistency on multiplication and division constraints. We show that even though the proof system and checker operate only on linear inequalities over 0-1 variables, non-linear reasoning over bounded domains can be efficiently expressed as a sequence of PB proof steps. Additionally, we demonstrate that bespoke proof logging for bounds-consistency algorithms offers a clear advantage over constructing justifications by brute force
Counter-pedagogies of cruelty: overcoming marginalization in Colombian accounting academia through feminist solidarity
Get PDFWe explore how women professors in Colombian accounting academia have drawn on feminist values and practices to resist colonial-modern-patriarchal structures by founding a research group dedicated to interdisciplinary studies. Using a Latin American feminist decolonial approach, we apply the concept of “Counter-pedagogies of cruelty” [Contra-pedagogías de la crueldad]. Methodologically, we conducted 21 in-depth interviews and collected written reflective accounts from professors – both men and women – and students who founded or participated in the research group. Our findings suggest that, to confront the norms of masculinity, these women created their own research group as a space of resistance, incorporating feminist values and practices to challenge colonial-modern-patriarchal structures. Their experience demonstrates how decolonial feminist praxis can be enacted despite institutional norms and constraints. We contribute to the literature on Feminist Organizing in Academia by adopting a decolonial perspective and amplifying Colombian and Latin American voices within the accounting field, showing how decolonial feminist principles can resist the entrenched norms of masculinity in both the accounting profession and academia
Predicting the mechanical properties of supramolecular gels
Get PDFThe prediction of gelation is an important target, yet current models do not predict any post-gel properties. Gels can be formed through the self-assembly of many molecules, but close analogs often do not form gels. There has been success using a number of computational approaches to understand and predict gelation from molecular structures. However, these approaches focus on whether or not a gel will form, not on the properties of the resulting gels. Critically, it is the properties of the gels that are important for a specific application, not simply whether a gel will be formed. Supramolecular gels are often kinetically trapped, meaning that predicting gel properties is inherently a difficult challenge. Here, the first successful a priori prediction of gel properties for such self-assembled, supramolecular systems is reported
Type systems and maximal subgroups of Thompson’s group V
Get PDFWe introduce the concept of a type system P, that is, a partition
on the set of finite words over the alphabet {0, 1} compatible with the partial action of Thompson’s group V , and associate a subgroup StabV (P) of V . We classify the finite simple type systems and show that the stabilizers of various simple type systems, including all finite simple type systems, are maximal subgroups of V . We also find an uncountable family of pairwise nonisomorphic maximal subgroups of V . These maximal subgroups occur as stabilizers of infinite simple type systems and have not been described in previous literature: specifically, they do not arise as stabilizers in V of finite sets of points in Cantor space. Finally, we show that two natural conditions on subgroups of V (both related to primitivity) are each satisfied only by V itself, giving new ways to recognise when a subgroup of V is not actually proper
Modelling Real-time Systems with Bigraphs
Get PDFBigraphical Reactive Systems (BRSs) are a graph-rewriting formalism describing systems evolving in two dimensions: spatially, e.g. a person in a room, and non-spatially, e.g. mobile phones communicating regardless of location. Despite use in domains including communication protocols, agent programming, biology, and security, there is no support for real-time systems. We extend BRSs to support real-time systems with a modelling approach that uses multiple perspectives to represent digital clocks. We use Action BRSs, a recent extension of BRSs, where the resulting transition system is a Markov Decision Process (MDP). This allows a natural representation of the choices in each system state: to either allow time to pass or perform a specific action. We implement our proposed approach using the BigraphER toolkit, and demonstrate the effectiveness through multiple examples including modelling cloud system requests
How refugees respond to hostile political discourse: no exit, but less voice
Get PDFHow does the political discourse about refugees influence their attitudes in the host country? Relying on an online survey and experiment conducted with Syrian refugees in Turkey and Germany, this study explores the relationship between political discourse and refugees’ two potential attitudinal responses: political integration and return. Our observational analysis demonstrates that refugees’ perception of the political discourses about them is the variable most consistently associated with attitudes in these domains. Our experimental results reveal that hostile political discourse, compared to a welcoming political discourse, undermines refugees’ political integration, weakening both their political interest and willingness to participate in host country politics. However, our experimental findings suggest that political discourse does not significantly impact refugees’ intentions to return. Overall, our results demonstrate that refugees’ perceptions of political discourse are an important determinant of their attitudes toward host country politics, and more research is warranted on the topic
Modelling Privacy Compliance in Cross-border Data Transfers with Bigraphs
Get PDFAdvancements in information technology have led to the sharing of users' data across borders, raising privacy concerns, particularly when destination countries lack adequate protection measures. Regulations like the European General Data Protection Regulation (GDPR) govern international data transfers, imposing significant fines on companies failing to comply. To achieve compliance, we propose a privacy framework based on Milner's Bigraphical Reactive Systems (BRSs), a formalism modelling spatial and non-spatial relationships between entities. BRSs evolve over time via user-specified rewriting rules, defined algebraically and diagrammatically. In this paper, we rely on diagrammatic notations, enabling adoption by end-users and privacy experts without formal modelling backgrounds. The framework comprises predefined privacy reaction rules modelling GDPR requirements for international data transfers, properties expressed in Computation Tree Logic (CTL) to automatically verify these requirements with a model checker and sorting schemes to statically ensure models are well-formed. We demonstrate the framework's applicability by modelling WhatsApp's privacy policies
Incidence of fatal and non-fatal pulmonary thromboembolism after removal of tunnelled central venous haemodialysis catheters without ultrasound scan and anticoagulation
Get PDFBackground:
Catheter related thrombosis is a common complication of tunnelled central venous catheter (TCVC) usage. There are concerns that TCVC removal could dislodge a thrombus to cause pulmonary thromboembolism (PE). The incidence of PE following TCVC removal is unclear and so the aim of this study was to investigate the incidence of PE and whether it is high enough to warrant screening with ultrasound with a view to systemic anticoagulation prior to TCVC removal.
Methods:
1102 consecutive TCVC removals without ultrasound and systemic anticoagulation were included in this retrospective study. Data were extracted from electronic health records. Measures to identify PE events included: deaths, computed tomography pulmonary angiogram (CT-PA), isotope lung perfusion scans and D-dimers blood tests within 7 days of removal.
Results:
Of the 1102 TCVC removals, the mean age of patients was 56.9 years and 57.3% were male. The primary renal diagnosis for 24.5% of patients was diabetic nephropathy. There were seven deaths following removal, none of which had PE as a contributing cause on review of their clinical history and death certificates. Five CT-PAs and one isotope lung perfusion scan were carried out in the 7 days after TCVC removal and none had a positive finding of PE. Three patient had D-dimers measured in blood within 7 days and none of these patients were subsequently diagnosed with PE.
Conclusions:
There was no evidence of fatal or non-fatal PE’s occurring in the 7 days following TCVC removal. This would support the practice of removing TCVCs without the need for ultrasound screening and without a period of systemic anticoagulation
Gender-affirming hormone therapy: effects on cardiovascular risk and vascular function
Get PDFBackground: Gender-affirming hormone therapy (GAHT) is used in individuals with gender identity dysphoria to align an individual’s secondary sexual characteristics with their affirmed gender. We conducted a systematic review of the literature to explore the mechanisms regarding the effects of GAHT on the vasculature. Methods: A literature search using PUBMED, Embase, Scopus and Lilacs was performed using search terms for GAHT, cardiovascular disease (CVD) risk and transgender. Studies were screened by two independent reviewers. Comparison to a cohort of transgender individuals naïve or prior to GAHT or a cisgender population was required. Quality assessment was done using the relevant Critical Skills Appraisal Programme checklists. Results: Out of 2,564 potentially eligible studies, 69 studies met the inclusion criteria. Studies provided evidence of beneficial changes in CVD risk profile including reduced haemoglobin and pro-inflammatory markers, and atheroprotective changes in lipids in transgender women. In transgender men there was evidence of negative changes in CVD risk profile including atherogenic changes in lipids and increased haemoglobin, arterial stiffness, and pro-inflammatory markers. Conclusions: There is a paucity of research across non-traditional measures of CVD risk which in combination with heterogeneous study design, loss of follow-up, low sample sizes and lack of diversity in age and ethnicity requires the results to be interpreted with caution. More evidence is required to elucidate the mechanisms behind the increased risk of CVD in the transgender population and determine if GAHT is a contributing factor
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