"Antiscepticism and Easy Justification" - Ch 5 of Seemings and Epistemic Justification

In this chapter I investigate epistemological consequences of the fact that seeming-based justification is elusive, in the sense that the subject can lose this justification simply by reflecting on her seemings. I argue that since seeming-based justification is elusive, the antisceptical bite of phenomenal conservatism is importantly limited. I also contend that since seeming-based justification has this feature, phenomenal conservatism isn’t actually afflicted by easy justification problems

On the Laplacian spectra of token graphs

We study the Laplacian spectrum of token graphs, also called symmetric powers of graphs. The k-token graph Fk(G) of a graph G is the graph whose vertices are the k-subsets of vertices from G, two of which being adjacent whenever their symmetric difference is a pair of adjacent vertices in G. In this paper, we give a relationship between the Laplacian spectra of any two token graphs of a given graph. In particular, we show that, for any integers h and k such that 1 ≤ h ≤ k ≤ n 2 , the Laplacian spectrum of Fh(G) is contained in the Laplacian spectrum of Fk(G). We also show that the doubled odd graphs and doubled Johnson graphs can be obtained as token graphs of the complete graph Kn and the star Sn = K1,n−1, respectively. Besides, we obtain a relationship between the spectra of the k-token graph of G and the k-token graph of its complement G. This generalizes to tokens graphs a wellknown property stating that the Laplacian eigenvalues of G are closely related to the Laplacian eigenvalues of G. Finally, the doubled odd graphs and doubled Johnson graphs provide two infinite families, together with some others, in which the algebraic connectivities of the original graph and its token graph coincide. Moreover, we conjecture that this is the case for any graph G and its token graph.This research of C. Dalfó and M.A. Fiol has been partially supported by AGAUR from the Catalan Government under project 017SGR1087 and by MICINN from the Spanish Government under project PGC2018-095471-B-I00. The research of C. Dalfó has also been supported by MICINN from the Spanish Government under project MTM2017-83271-R. The research of C. Huemer was supported by MICINN from the Spanish Government under project PID2019-104129GB-I00/AEI/10.13039/501100011033 and AGAUR from the Catalan Government under project 017SGR1336. F.J. Zaragoza Martínez acknowledges the support of the National Council of Science and Technology (Conacyt) and its National System of Researchers (SNI). This research has also received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 73492

Rubber friction: role of the flash temperature

When a rubber block is sliding on a hard rough substrate, the substrate asperities will exert time-dependent deformations of the rubber surface resulting in viscoelastic energy dissipation in the rubber, which gives a contribution to the sliding friction. Most surfaces of solids have roughness on many different length scales, and when calculating the friction force it is necessary to include the viscoelastic deformations on all length scales. The energy dissipation will result in local heating of the rubber. Since the viscoelastic properties of rubber-like materials are extremely strongly temperature dependent, it is necessary to include the local temperature increase in the analysis. At very low sliding velocity the temperature increase is negligible because of heat diffusion, but already for velocities of order 0.01 m/s the local heating may be very important. Here I study the influence of the local heating on the rubber friction, and I show that in a typical case the temperature increase results in a decrease in rubber friction with increasing sliding velocity for v > 0.01 m/s. This may result in stick-slip instabilities, and is of crucial importance in many practical applications, e.g., for the tire-road friction, and in particular for ABS-breaking systems.Comment: 22 pages, 27 figure

Realism, Objectivity, and Evaluation

I discuss Benacerraf's epistemological challenge for realism about areas like mathematics, metalogic, and modality, and describe the pluralist response to it. I explain why normative pluralism is peculiarly unsatisfactory, and use this explanation to formulate a radicalization of Moore's Open Question Argument. According to the argument, the facts -- even the normative facts -- fail to settle the practical questions at the center of our normative lives. One lesson is that the concepts of realism and objectivity, which are widely identified, are actually in tension

"Cognitive Penetrability" - Ch 3 of Seemings and Epistemic Justification

In this chapter I introduce the thesis that perceptual appearances are cognitively penetrable and analyse cases made against phenomenal conservatism hinging on this thesis. In particular, I focus on objections coming from the externalist reliabilist camp and the internalist inferentialist camp. I conclude that cognitive penetrability doesn’t yield lethal or substantive difficulties for phenomenal conservatism

The protease associated (PA) domain in ScpA from Streptococcus pyogenes plays a role in substrate recruitment

Annually, over 18 million disease cases and half a million deaths worldwide are estimated to be caused by Group A Streptococcus. ScpA (or C5a peptidase) is a well characterised member of the cell enveleope protease family, which possess a S8 subtilisin-like catalytic domain and a shared multi-domain architecture. ScpA cleaves complement factors C5a and C3a, impairing the function of these critical anaphylatoxins and disrupts complement-mediated innate immunity. Although the high resolution structure of ScpA is known, the details of how it recognises its substrate are only just emerging. Previous studies have identified a distant exosite on the 2nd fibronectin domain that plays an important role in recruitment via an interaction with the substrate core. Here, using a combination of solution NMR spectroscopy, mutagenesis with functional assays and computational approaches we identify a second exosite within the protease-associated (PA) domain. We propose a model in which the PA domain assists optimal delivery of the substrate's C terminus to the active site for cleavage

Safety and Healthcare Resource Utilization in Patients Undergoing Left Atrial Appendage Closure—A Nationwide Analysis

Percutaneous left atrial appendage closure (LAAC) has emerged as a non-pharmacological alternative for stroke prevention in patients with atrial fibrillation (AF) not suitable for anticoagulation therapy. Real-world data on peri-procedural outcomes are limited. The aim of this study was to analyze outcomes of peri-procedural safety and healthcare resource utilization in 11,240 adult patients undergoing LAAC in the United States between 2016 and 2019. Primary outcomes (safety) were in-hospital ischemic stroke or systemic embolism (SE), pericardial effusion (PE), major bleeding, device embolization and mortality. Secondary outcomes (resource utilization) were adverse discharge disposition, hospital length of stay (LOS) and costs. Logistic and Poisson regression models were used to analyze outcomes by adjusting for 10 confounders. SE decreased by 97% between 2016 and 2019 [95% Confidence Interval (CI) 0-0.24] (p = 0.003), while a trend to lower numbers of other peri-procedural complications was determined. In-hospital mortality (0.14%) remained stable. Hospital LOS decreased by 17% (0.78-0.87, p < 0.001) and adverse discharge rate by 41% (95% CI 0.41-0.86, p = 0.005) between 2016 and 2019, while hospital costs did not significantly change (p = 0.2). Female patients had a higher risk of PE (OR 2.86 [95% CI 2.41-6.39]) and SE (OR 5.0 [95% CI 1.28-43.6]) while multi-morbid patients had higher risks of major bleeding (p < 0.001) and mortality (p = 0.031), longer hospital LOS (p < 0.001) and increased treatment costs (p = 0.073). Significant differences in all outcomes were observed between male and female patients across US regions. In conclusion, LAAC has become a safer and more efficient procedure. Significant sex differences existed across US regions. Careful considerations should be taken when performing LAAC in female and comorbid patients

Cross-sectional observational study of 208 patients with non-classical urea cycle disorders.

Urea cycle disorders (UCDs) are inherited disorders of ammonia detoxification often regarded as mainly of relevance to pediatricians. Based on an increasing number of case studies it has become obvious that a significant number of UCD patients are affected by their disease in a non-classical way: presenting outside the newborn period, following a mild course, presenting with unusual clinical features, or asymptomatic patients with only biochemical signs of a UCD. These patients are surviving into adolescence and adulthood, rendering this group of diseases clinically relevant to adult physicians as well as pediatricians. In preparation for an international workshop we collected data on all patients with non-classical UCDs treated by the participants in 20 European metabolic centres. Information was collected on a cohort of 208 patients 50% of which were ≥ 16 years old. The largest subgroup (121 patients) had X-linked ornithine transcarbamylase deficiency (OTCD) of whom 83 were female and 29% of these were asymptomatic. In index patients, there was a mean delay from first symptoms to diagnosis of 1.6 years. Cognitive impairment was present in 36% of all patients including female OTCD patients (in 31%) and those 41 patients identified presymptomatically following positive newborn screening (in 12%). In conclusion, UCD patients with non-classical clinical presentations require the interest and care of adult physicians and have a high risk of neurological complications. To improve the outcome of UCDs, a greater awareness by health professionals of the importance of hyperammonemia and UCDs, and ultimately avoidance of the still long delay to correctly diagnose the patients, is crucial