In this paper, we investigate how the COVID-19 health crisis could affect the liquidity of listed firms across 26 countries. We stress-test three liquidity ratios for each firm with full and partial ...operating flexibility in two simulated distress scenarios corresponding to drops in sales of 50% and 75%, respectively. In the most adverse scenario, the average firm with partial operating flexibility would exhaust its cash holdings in about two years. At that point, its current liabilities would increase, on average, by eight times, suggesting that the average firm would have to resort to the debt market to prevent a liquidity crunch. Moreover, about 1/10th of all sample firms would become illiquid within six months. Finally, we study two different fiscal policies, tax deferrals and bridge loans, that governments could implement to mitigate the liquidity risk. Our analysis suggests bridge loans are more cost-effective to prevent a massive cash crunch.
We study compensation contracts of individual portfolio managers using handcollected data of over 4,500 U.S. mutual funds. Variations in the compensation structures are broadly consistent with an ...optimal contracting equilibrium. The likelihood of explicit performance-based incentives is positively correlated with the intensity of agency conflicts, as proxied by the advisor's clientele dispersion, its affiliations in the financial industry, and its ownership structure. Investor sophistication and the threat of dismissal in outsourced funds serve as substitutes for explicit performancebased incentives. Finally, we find little evidence of differences in future performance associated with any particular compensation arrangement.
Leptin is one of the most relevant factors secreted by adipose tissue and the forerunner of a class of molecules collectively called adipokines. Initially discovered in 1994, its crucial role as a ...central regulator in energy homeostasis has been largely described during the past 20 years. Once secreted into the circulation, leptin reaches the central and peripheral nervous systems and acts by binding and activating the long form of leptin receptor (LEPR), regulating appetite and food intake, bone mass, basal metabolism, reproductive function and insulin secretion, among other processes. Research on the regulation of different adipose tissues has provided important insights into the intricate network that links nutrition, metabolism and immune homeostasis. The neuroendocrine and immune systems communicate bi-directionally through common ligands and receptors during stress responses and inflammation, and control cellular immune responses in several pathological situations including immune-inflammatory rheumatic diseases. This Review discusses the latest findings regarding the role of leptin in the immune system and metabolism, with particular emphasis on its effect on autoimmune and/or inflammatory rheumatic diseases, such as rheumatoid arthritis and osteoarthritis.
Ribosomes are the highly complex macromolecular assemblies dedicated to the synthesis of all cellular proteins from mRNA templates. The main principles underlying the making of ribosomes are ...conserved across eukaryotic organisms and this process has been studied in most detail in the yeast Saccharomyces cerevisiae. Yeast ribosomes are composed of four ribosomal RNAs (rRNAs) and 79 ribosomal proteins (r-proteins). Most r-proteins need to be transported from the cytoplasm to the nucleus where they get incorporated into the evolving pre-ribosomal particles. Due to the high abundance and difficult physicochemical properties of r-proteins, their correct folding and fail-safe targeting to the assembly site depends largely on general, as well as highly specialized, chaperone and transport systems. Many r-proteins contain universally conserved or eukaryote-specific internal loops and/or terminal extensions, which were shown to mediate their nuclear targeting and association with dedicated chaperones in a growing number of cases. The 60S r-protein Rpl4 is particularly interesting since it harbours a conserved long internal loop and a prominent C-terminal eukaryote-specific extension. Here we show that both the long internal loop and the C-terminal eukaryote-specific extension are strictly required for the functionality of Rpl4. While Rpl4 contains at least five distinct nuclear localization signals (NLS), the C-terminal part of the long internal loop associates with a specific binding partner, termed Acl4. Absence of Acl4 confers a severe slow-growth phenotype and a deficiency in the production of 60S subunits. Genetic and biochemical evidence indicates that Acl4 can be considered as a dedicated chaperone of Rpl4. Notably, Acl4 localizes to both the cytoplasm and nucleus and it has the capacity to capture nascent Rpl4 in a co-translational manner. Taken together, our findings indicate that the dedicated chaperone Acl4 accompanies Rpl4 from the cytoplasm to its pre-60S assembly site in the nucleus.
Genetic structure can be influenced by local adaptation to environmental heterogeneity and biogeographic barriers, resulting in discrete population clusters. Geographic distance among populations, ...however, can result in continuous clines of genetic divergence that appear as structured populations. Here, we evaluate the relevant importance of these three factors over a landscape characterized by environmental heterogeneity and the presence of a hypothesized biogeographic barrier in producing population genetic structure within 13 codistributed snake species using a genomic data set. We demonstrate that geographic distance and environmental heterogeneity across western North America contribute to population genomic divergence. Surprisingly, landscape features long thought to contribute to biogeographic barriers play little role in divergence community wide. Our results suggest that isolation by environment is the most important contributor to genomic divergence. Furthermore, we show that models of population clustering that incorporate spatial information consistently outperform nonspatial models, demonstrating the importance of considering geographic distances in population clustering. We argue that environmental and geographic distances as drivers of community‐wide divergence should be explored before assuming the role of biogeographic barriers.
see also the Perspective by Alencar and Quental
We study how the scarcity of committed capital affects the equilibrium distribution of net alphas in the asset management industry. We propose a model of active portfolio management with different ...sales fee structures where committed capital is in short supply. In the model, a portfolio’s excess return is not fully appropriated by the money manager but shared with long-term investors. Empirically, we show that capital commitment allows funds to hold shares longer and take advantage of slow-moving arbitrage opportunities. Consistent with the model, funds with more committed capital generate higher value added, which, net of fees, accrues to long-term investors.
C2 domains are membrane-binding modules that share a common overall fold: a single compact Greek-key motif organized as an eight-stranded anti-parallel β-sandwich consisting of a pair of ...four-stranded β-sheets. A myriad of studies have demonstrated that in spite of sharing the common structural β-sandwich core, slight variations in the residues located in the interconnecting loops confer C2 domains with functional abilities to respond to different Ca2+ concentrations and lipids, and to signal through protein–protein interactions as well. This review summarizes the main structural and functional findings on Ca2+ and lipid interactions by C2 domains, including the discovery of the phosphoinositide-binding site located in the β3–β4 strands. The wide variety of functions, together with the different Ca2+ and lipid affinities of these domains, converts this superfamily into a crucial player in many functions in the cell and more to be discovered. This Article is Part of a Special Issue Entitled: Membrane Structure and Function: Relevance in the Cell's Physiology, Pathology and Therapy.
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•Many C2 domains interact with membranes in a Ca2+-dependent manner.•The CBR determines the ability of C2 domains to bind membranes in a Ca2+-dependent way.•The polybasic cluster confers the PtdIns(4,5)P2 specificity.•Some of these domains might be regulated by a dual-target mechanism.
The electrochemical CO2 reduction reaction (CO2RR) is a promising technology for converting waste CO2 into synthetic fuels and carbon-based chemicals using renewable electricity. Most efforts have ...been dedicated to improving the selectivity at high current densities bringing this process closer to commercial application. However, the long-term stability of the process has received considerably less attention. In this review, we present the progress made on long-term CO2 electrolysis to bring attention to the crucial piece of the puzzle. While Ag-based electrolyzers for CO production have met the desired durability requirements, this is not yet the case for other catalysts. Therefore, we also review the possible degradation pathways affecting both the catalyst material and the electrolyzer and address different strategies to mitigate them.
Abstract
Objective
The lack of representative coronavirus disease 2019 (COVID-19) data is a bottleneck for reliable and generalizable machine learning. Data sharing is insufficient without data ...quality, in which source variability plays an important role. We showcase and discuss potential biases from data source variability for COVID-19 machine learning.
Materials and Methods
We used the publicly available nCov2019 dataset, including patient-level data from several countries. We aimed to the discovery and classification of severity subgroups using symptoms and comorbidities.
Results
Cases from the 2 countries with the highest prevalence were divided into separate subgroups with distinct severity manifestations. This variability can reduce the representativeness of training data with respect the model target populations and increase model complexity at risk of overfitting.
Conclusions
Data source variability is a potential contributor to bias in distributed research networks. We call for systematic assessment and reporting of data source variability and data quality in COVID-19 data sharing, as key information for reliable and generalizable machine learning.
This paper presents the design of a wireless sensor network particularly designed for remote monitoring and control of industrial parameters. The article describes the network components, protocol ...and sensor deployment, aimed to accomplish industrial constraint and to assure reliability and low power consumption. A particular case of study is presented. The system consists of a base station, gas sensing nodes, a tree-based routing scheme for the wireless sensor nodes and a real-time monitoring application that operates from a remote computer and a mobile phone. The system assures that the industrial safety quality and the measurement and monitoring system achieves an efficient industrial monitoring operations. The robustness of the developed system and the security in the communications have been guaranteed both in hardware and software level. The system is flexible and can be adapted to different environments. The testing of the system confirms the feasibility of the proposed implementation and validates the functional requirements of the developed devices, the networking solution and the power consumption management.
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