Breakpoint Analysis for the COVID-19 Pandemic and Its Effect on the Stock Markets

In this research, statistical models are formulated to study the effect of the health crisis arising from COVID-19 in global markets. Breakpoints in the price series of stock indexes are considered. Such indexes are used as an approximation of the stock markets in different countries, taking into account that they are indicative of these markets because of their composition. The main results obtained in this investigation highlight that countries with better institutional and economic conditions are less affected by the pandemic. In addition, the effect of the health index in the models is associated with their non-significant parameters. This is due to that the health index used in the modeling would not determine the different capacities of the countries analyzed to respond efficiently to the pandemic effect. Therefore, the contagion is the preponderant factor when analyzing the structural breakdown that occurred in the world economy.

Effect of pasta shape and gluten on pasta cooking quality and structural breakdown during mastication

Oral processing behaviour of food is affected by the structural characteristics of the food matrix, including rheological and mechanical attributes as well as size and shape. Pasta, a staple starchy...

Comments on “The nature of theory in information systems”

This commentary is on Shirley Gregor’s (2006) article titled “The Nature of Theory in Information Systems”, published in MIS Quarterly. In terms of theories, five types have been prominent in Gregor’s classification: (a) Theory of Analyzing (b) Theory of Explaining (c) Theory of Prediction (d) Theory of Explaining and Predicting (e) Theory of Design and Action. The author argued that this can help researchers to choose a differing epistemological approach to develop a theory that is under development. Furthermore, a structural breakdown of the theory has been projected that gives a better and clear understanding of the essential parts of the theory to researchers. However, some important questions emerge after reading the most cited article about the nature of theory in IS. The major ones are: (a) What is the difference between theory in general and theory in IS?, (b) Are the structural parts of the theory described by Gregor exhaustive and correctly presented?, (c) Different classifications of theories presented by Gregor are theory or theorizing in nature, and finally, (d) Gregor argued that management scientists did not provide anything regarding design and action theory, is that true?

Effects of Fungi-Mediated Solid-State Fermentation on Phenolic Contents and Antioxidant Activity of Brown and White Teff (Eragrostis tef (Zucc.) Trotter) Grains

Teff (Eragrostis tef (Zucc.) Trotter) is a tropical cereal used in preparing a staple food in Ethiopia and Eritrea called injera. Phenolic compounds are available in soluble and bound forms in cereals like teff. Therefore, their bioaccessibility depends on their release from the food matrix. Different food processing methods including fermentation have been applied since ancient times to aid bioaccessibility and improve the properties of food products. This study aimed at investigating changes in phenolic profiles and antioxidant activities of white and brown teff grains during mushroom-mediated solid-state fermentation. Fermentation with mushroom considerably increased total phenol contents of the soluble phenol fraction with Ganoderma lucidum showing relatively higher increase than Pleurotus ostreatus. Bound fraction of teff phenol did not show noticeable changes after fermentation with the two mushroom strains. Such changes are suggested to be attributed to activities of fungal enzymes such as amylases, xylanases, and proteases that induce structural breakdown of grain components including cell walls leading to the liberation or synthesis of a variety of phenolic compounds. On the other hand, total flavonoid content of teff significantly decreased after fermentation by both strains. This is also believed to be caused by the action of fungal polyphenol oxidases that catalyze the oxidation of a variety of phenolic compounds including flavonoids to o-quinones.

Dating deformation: multichronometric examples from the Western Alps, Naxos, and the Garhwal Himalaya

<p>In the eclogite facies shear zone of Bottarello, Monte Rosa, Western Alps [1], fault recrystallization around 600 °C gives concordant Lu-Hf (garnet) and <sup>39</sup>Ar-<sup>40</sup>Ar (white mica, WM) 47 Ma ages whereas <100 m from the fault the unsheared rock at the same T preserves Mesozoic inheritance. The Ar retentivity of WM is not accurately predicted by hydrothermal laboratory experiments, because the latter are plagued by massive dissolution artefacts [2]. Independent field observations confirm that WM only starts losing Ar in dry rocks above 600 °C [3-8], but when retrograde reactions occur, WM can recrystallize and be totally reset below 230 °C [9]. The Bottarello fault obliterated all relict WM from the protolith; the neoformed WM records its own formation age.</p><p>The island of Naxos (Cyclades, Greece) is the classic example of multiple, coexisting WM generations [10]: relict pre-eclogitic basement WM, and eclogitic phengite retrograded to muscovite. Electron microprobe element maps demonstrate intergrowths at a scale <5 µm, which makes laser microprobe dating useless. Bulk mica dissolution for Rb-Sr gives Eocene ages [11], which agree with bulk K-Ar ages. This is paradoxical, as Ar diffusivity is c. 4 orders of magnitude higher than that of Sr [12]; the only explanation is that both chronometric systems record formation ages around 500-600 °C. The WM generations can be unravelled by their Ca/Cl/K signatures; coarse and fine sieve fractions are never isomineralic. Ages of pure mica generations are obtained by extrapolating Ca/Cl/K-vs-age trends.</p><p>The in-sequence thrusts of the Garhwal Himalaya add one complication: thrusting was long-lived. Microstructures combined with chemical microanalysis distinguish three monazite generations (dated by U-Pb) and three WM generations: relicts in microlithons, foliation-defining mica, and static coronas. As in the previous examples, intergrowths are <<10 µm and only combining Ca/Cl/K systematics with the observed differences in structural breakdown temperatures can assign the different WM ages in the same sample to chemically distinct generations [13]. WM formation ages overlap with Mnz ages and date the onset of faulting, the kinematic peak, and the post-faulting corona formation.</p><p>There is no free lunch: dating deformation is extremely labor-intensive and requires, always, establishing the context between microtextural, microchemical, petrological and multichronometric analyses. Whenever one of these four is missing, the tectonic reconstruction is invariably faulty [14].</p><p> </p><p>[1] Villa &al, J Petrol 55 (2014) 803-830</p><p>[2] Villa, Geol Soc London Spec Pub 332 (2010) 1-15</p><p>[3] Di Vincenzo &al, J Petrol 45 (2004) 1013-1043</p><p>[4] Itaya &al, Island Arc 18 (2009) 293-305</p><p>[5] Heri &al, Geol Soc London Spec Pub 378 (2014) 69-78</p><p>[6] Laurent &al, Lithos, 272-273 (2017) 315-335</p><p>[7] Airaghi &al, J Metam Geol 36 (2018) 933-958</p><p>[8] Imayama &al, Geol Soc London Spec Pub 481 (2019) 147-173</p><p>[9] Maineri &al, Mineralium Deposita 38 (2003) 67-86</p><p>[10 Wijbrans & McDougall, Contrib Min Petr 93 (1986) 187-194</p><p>[11] Peillod &al, J Metam Geol 35 (2017) 805-830</p><p>[12] Cherniak & Watson, EPSL 113 (1992) 411-425</p><p>[13] Montemagni &al, Geol Soc London Spec Pub 481 (2019) 127-146</p><p>[14] Bosse & Villa, Gondwana Res 71 (2019) 76-90</p>