The stock market response to COVID-19 : evidence from five developed markets

This study evaluates the connection between stock returns and the COVID-19 pandemic in five developed markets, including Canada, France, Germany, the United Kingdom, and the United States. The analysis is based on observations ranging from December 2019, when the first official cases of the new virus were discovered, to April 2022 and uses data from 3,120 firms. Stock returns reacted negatively to the growth of cumulative cases and deaths in the overall sample as well as across four of the five countries, except for the United Kingdom. While the relation between lockdowns and stock performance is also negative, fiscal stimuli seem to have a positive impact. Furthermore, I find that higher perceived risk and rising uncertainty, measured by Google search volume and a policy uncertainty index based on news, are also related to lower performance in most regression specifications. It can be observed that smaller companies in my sample suffer more from a higher growth rate of cumulative cases than medium-sized ones and the largest firms even experience a positive effect. Finally, I show that industry affiliation matters. The pandemic-related change in stock returns across industries varies in statistical and economic significance, with some coefficients being positive and others negative.Este estudo avalia a relação entre o retorno das acções e a pandemia da COVID-19 em cinco mercados desenvolvidos, incluindo Canadá, França, Alemanha, o Reino Unido e os Estados Unidos. A análise baseia-se em observações que vão desde Dezembro de 2019, quando foram descobertos os primeiros casos oficiais do novo vírus, até Abril de 2022, e utiliza dados de 3.120 empresas. Os retornos das acções reagiram negativamente ao crescimento de casos e mortes acumulados na amostra global, bem como em quatro dos cinco países, com excepção do Reino Unido. Embora a relação entre lockdowns e o retorno de acções seja também negativa, os estímulos fiscais parecem ter um impacto positivo. Além disso, considero que o maior risco percebido e a crescente incerteza, medida pelo volume de pesquisa do Google e um índice de incerteza política baseado em notícias, estão também relacionados com um desempenho inferior na maioria das especificações de regressão. Pode-se observar que as Menores empresas de minha amostra sofrem mais com uma taxa de crescimento mais elevada de casos cumulativos do que as de média dimensão e as maiores empresas experimentam mesmo um efeito positivo. Finalmente, mostro que a filiação na indústria é importante. A alteração relacionada com a pandemia nos retornos de stocks entre indústrias varia em termos de significância estatística e económica, com alguns coeficientes a serem positivos e outros negativos

Interpretation of precision tests in the Higgs sector in terms of physics beyond the Standard Model

We demonstrate how the measurements of the Higgs-fermion and Higgs-gauge boson couplings can be interpreted in terms of physics beyond the Standard Model in a model-independent way. That is, we describe deviations from the Standard Model by effective $d=6$ operators made of Higgs fields and gauge fields, under the hypothesis that the new physics may show up in the Higgs sector only and the effective operators are generated at tree level. While the effective operator coefficients are independent in general, the completion of the theory at high energies will lead to specific correlations which will be recovered between Higgs-fermion and Higgs-gauge boson couplings. We demonstrate that the current measurement of these couplings in terms of tree-level new physics requires several new mediators with specific relationships among different couplings. New insights in the effective theory and mediator spaces can be expected for improved measurements from the inclusive $H \rightarrow \tau \tau$ and the exclusive vector boson fusion-dominated $H \rightarrow \gamma \gamma$ search channels, as well as the measurement of the Higgs self-couplings, including higher order couplings which do not exist in the Standard Model.Comment: 12 pages, 2 figures; v2: some discussions extended, conclusions unchanged; version to appear in PR

Detection of 133^{133}Xe from the Fukushima nuclear power plant in the upper troposphere above Germany

After the accident in the Japanese Fukushima Dai-ichi nuclear power plant in March 2011 large amounts of radioactivity were released and distributed in the atmosphere. Among them were also radioactive noble gas isotopes which can be used as tracers to test global atmospheric circulation models. This work presents unique measurements of the radionuclide $^{133}$Xe from Fukushima in the upper troposphere above Germany. The measurements involve air sampling in a research jet aircraft followed by chromatographic xenon extraction and ultra-low background gas counting with miniaturized proportional counters. With this technique a detection limit of the order of 100 $^{133}$Xe atoms in litre-scale air samples (corresponding to about 100 mBq/m$^3$) is achievable. Our results provide proof that the $^{133}$Xe-rich ground level air layer from Fukushima was lifted up to the tropopause and distributed hemispherically. Moreover, comparisons with ground level air measurements indicate that the arrival of the radioactive plume at high altitude over Germany occurred several days before the ground level plume.Comment: 8 pages, 5 figure

Tetracationic bis-triarylborane 1, 3-butadiyne as a combined fluorimetric and Raman probe for simultaneous and selective sensing of various DNA, RNA and proteins

A new bis-triarylborane tetracation (4-Ar2B-3, 5-Me2C6H2)-C≡C- C≡C-(3, 5-Me2C6H2-4-BAr2 [Ar = (2, 6-Me2-4-NMe3-C6H2)+] (24+) shows distinctly different behaviour in its fluorimetric response than that of our recently published bis-triarylborane 5- (4-Ar2B-3, 5-Me2C6H2)-2, 2’-(C4H2S)2-5’-(3, 5-Me2C6H2-4-BAr2) (34+). Single-crystal X-ray diffraction data on the neutral bis- triarylborane precursor 2N confirm its rod-like dumbbell structure, which is shown to be important for DNA/RNA targeting and also for BSA protein binding. Fluorimetric titrations with DNA/RNA/BSA revealed the very strong affinity of 24+ and indicated the importance of the properties of the linker connecting the two triarylboranes. Using the butadiyne- rather than a bithiophene linker resulted in an opposite emission effect (quenching vs enhancement), and 24+ bound to BSA 100 times stronger than 34+. Moreover, 24+ interacted strongly with ss-RNA, and circular dichroism (CD) results suggest ss- RNA chain-wrapping around the rod-like bis-triarylborane dumbbell structure like a thread around a spindle, a very unusual mode of binding of ss-RNA with small molecules. Furthermore, 24+ yielded strong Raman/SERS signals, allowing DNA or protein detection at ca. 10 nM concentrations. The above observations, combined with low cytotoxicity, efficient human cell uptake and organelle-selective accumulation make such compounds intriguing novel lead structures for bio-oriented, dual fluorescence/Raman-based applications

Formate Oxidase (FOx) from Aspergillus oryzae: One Catalyst Enables Diverse H 2 O 2 -Dependent Biocatalytic Oxidation Reactions

An increasing number of biocatalytic oxidation reactions rely on H2O2 as a clean oxidant. The poor robustness of most enzymes towards H2O2, however, necessitates more efficient systems for in situ H2O2 generation. In analogy to the well‐known formate dehydrogenase to promote NADH‐dependent reactions, we here propose employing formate oxidase (FOx) to promote H2O2‐dependent enzymatic oxidation reactions. Even under non‐optimised conditions, high turnover numbers for coupled FOx/peroxygenase catalysis were achieved.The authors gratefully acknowledge funding by the European Research Commission (ERC consolidator grant, No. 648026), the European Union (H2020‐BBI‐PPP‐2015‐2‐1‐720297), the Netherlands Organisation for Scientific Research (VICI grant No. 724.014.003), the National Science Foundation (NSF) of the United States (grant IIP‐1540017) and the Comunidad de Madrid Synergy CAM ProjectOrganisation for Scientific Research