Discounting disentangled

The economic values of investing in long-term public projects are highly sensitive to the social discount rate (SDR). We surveyed over 200 experts to disentangle disagreement on the risk-free SDR into its component parts, including pure time preference, the wealth effect, and return to capital. We show that the majority of experts do not follow the simple Ramsey Rule, a widely used theoretical discounting framework, when recommending SDRs. Despite disagreement on discounting procedures and point values, we obtain a surprising degree of consensus among experts, with more than three-quarters finding the median risk-free SDR of 2 percent acceptable

Application of Pyroprinting for Source Tracking of E. coli in Pennington Creek

The goal of this project is to determine the source of fecal contamination in Pennington Creek. Dangerously high numbers of E. coli were recorded in the creek by the Morro Bay National Estuary Program (MBNEP) over the last 10 years. This is of particular concern because the creek runs directly through an outdoor school for K-12 education. One potential source of the contamination is the cattle in fields on either side of the creek for several miles, though they are supposedly kept out by fences. Another possibility is local wildlife—specifically wild turkeys, which roam around in flocks of over 100 and commonly roost directly over the creek. The Cal Poly Pyroprinting Project, housed in the Chevron Center for Applications in Biotechnology, is building a comprehensive database of genetic fingerprints (pyroprints) of E. coli from local wildlife and domestic animals for use in bacterial source tracking. Strain-specific pyroprints of E. coli isolates from the water body of interest are matched against wildlife pyroprints in the database. The two are matched up in a way similar to the matching of fingerprints, hence the term “pyroprints”. We will collect E. coli from two locations along Pennington Creek (labeled CPN and PEN) over a 16-month period, with additional bimonthly monitoring of overall E. coli counts. The two sites, along with an extended sampling period, will provide a good idea of the spatiotemporal fluctuations in concentration and sources of E. coli in the creek. The MBNEP has offered to help with the project by providing half of the supplies and reagents. The results of this project will be ultimately used by Cal Poly and the MBNEP to guide management decisions regarding Pennington Creek

The algal pyrenoid: key unanswered questions.

The confinement of Rubisco in a chloroplast microcompartment, or pyrenoid, is a distinctive feature of most microalgae, and contributes to perhaps ~30 Pg of carbon fixed each year, yet our understanding of pyrenoid composition, regulation, and function remains fragmentary. Recently, significant progress in understanding the pyrenoid has arisen from studies using mutant lines, mass spectrometric analysis of isolated pyrenoids, and advanced ultrastructural imaging of the microcompartment in the model alga Chlamydomonas. The emergence of molecular details in other lineages provides a comparative framework for this review, and evidence that most pyrenoids function similarly, even in the absence of a common ancestry. The objective of this review is to explore pyrenoid diversity throughout key algal lineages and discuss whether common ultrastructural and cellular features are indicative of common functional processes. By characterizing pyrenoid origins in terms of mechanistic and structural parallels, we hope to provide key unanswered questions which will inform future research directions

Semi-rational engineering of Adh2 for improved methanol utilization in Komagataella phaffii

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Mycolactone-dependent depletion of endothelial cell thrombomodulin is strongly associated with fibrin deposition in Buruli ulcer lesions

A well-known histopathological feature of diseased skin in Buruli ulcer (BU) is coagulative necrosis caused by the Mycobacterium ulcerans macrolide exotoxin mycolactone. Since the underlying mechanism is not known, we have investigated the effect of mycolactone on endothelial cells, focussing on the expression of surface anticoagulant molecules involved in the protein C anticoagulant pathway. Congenital deficiencies in this natural anticoagulant pathway are known to induce thrombotic complications such as purpura fulimans and spontaneous necrosis. Mycolactone profoundly decreased thrombomodulin (TM) expression on the surface of human dermal microvascular endothelial cells (HDMVEC) at doses as low as 2ng/ml and as early as 8hrs after exposure. TM activates protein C by altering thrombin's substrate specificity, and exposure of HDMVEC to mycolactone for 24 hours resulted in an almost complete loss of the cells' ability to produce activated protein C. Loss of TM was shown to be due to a previously described mechanism involving mycolactone-dependent blockade of Sec61 translocation that results in proteasome-dependent degradation of newly synthesised ER-transiting proteins. Indeed, depletion from cells determined by live-cell imaging of cells stably expressing a recombinant TM-GFP fusion protein occurred at the known turnover rate. In order to determine the relevance of these findings to BU disease, immunohistochemistry of punch biopsies from 40 BU lesions (31 ulcers, nine plaques) was performed. TM abundance was profoundly reduced in the subcutis of 78% of biopsies. Furthermore, it was confirmed that fibrin deposition is a common feature of BU lesions, particularly in the necrotic areas. These findings indicate that there is decreased ability to control thrombin generation in BU skin. Mycolactone's effects on normal endothelial cell function, including its ability to activate the protein C anticoagulant pathway are strongly associated with this. Fibrin-driven tisischemia could contribute to the development of the tissue necrosis seen in BU lesions

Modelling the way mathematics is actually done

Whereas formal mathematical theories are well studied, computers cannot yet adequately represent and reason about mathematical dialogues and other informal texts. To address this gap, we have developed a representation and reasoning strategy that draws on contemporary argumentation theory and classic AI techniques for representing and querying narratives and dialogues. In order to make the structures that these modelling tools produce accessible to computational reasoning, we encode representations in a higherorder nested semantic network. This system, for which we have developed a preliminary prototype in LISP, can represent both the content of what people say, and the dynamic reasoning steps that move from one step to the next

Wavelet-Packet Powered Deepfake Image Detection

As neural networks become more able to generate realistic artificial images, they have the potential to improve movies, music, video games and make the internet an even more creative and inspiring place. Yet, at the same time, the latest technology potentially enables new digital ways to lie. In response, the need for a diverse and reliable toolbox arises to identify artificial images and other content. Previous work primarily relies on pixel-space CNN or the Fourier transform. To the best of our knowledge, wavelet-based gan analysis and detection methods have been absent thus far. This paper aims to fill this gap and describes a wavelet-based approach to gan-generated image analysis and detection. We evaluate our method on FFHQ, CelebA, and LSUN source identification problems and find improved or competitive performance.Comment: Source code is available at https://github.com/gan-police/frequency-forensic