Numerical simulations of transverse oscillations in radiatively cooling coronal loops

We aim to study the influence of radiative cooling on the standing kink oscillations of a coronal loop. Using the FLASH code, we solved the 3D ideal magnetohydrodynamic equations. Our model consists of a straight, density enhanced and gravitationally stratified magnetic flux tube. We perturbed the system initially, leading to a transverse oscillation of the structure, and followed its evolution for a number of periods. A realistic radiative cooling is implemented. Results are compared to available analytical theory. We find that in the linear regime (i.e. low amplitude perturbation and slow cooling) the obtained period and damping time are in good agreement with theory. The cooling leads to an amplification of the oscillation amplitude. However, the difference between the cooling and non-cooling cases is small (around 6% after 6 oscillations). In high amplitude runs with realistic cooling, instabilities deform the loop, leading to increased damping. In this case, the difference between cooling and non-cooling is still negligible at around 12%. A set of simulations with higher density loops are also performed, to explore what happens when the cooling takes place in a very short time (tcool = 100 s). We strengthen the results of previous analytical studies that state that the amplification due to cooling is ineffective, and its influence on the oscillation characteristics is small, at least for the cases shown here. Furthermore, the presence of a relatively strong damping in the high amplitude runs even in the fast cooling case indicates that it is unlikely that cooling could alone account for the observed, flare-related undamped oscillations of coronal loops. These results may be significant in the field of coronal seismology, allowing its application to coronal loop oscillations with observed fading-out or cooling behaviour

Accurate Adiabatic Connection Curve Beyond the Physical Interaction Strength

The adiabatic connection curve of density functional theory (DFT) is accurately calculated beyond the physical interaction strength for Hooke's atom, two interacting electrons in a harmonic well potential. Extrapolation of the accurate curve to the infinite coupling limit agrees well with the strictly correlated electron (SCE) hypothesis but the approach to this limit is more complex. The interaction strength interpolation is shown to be a good, but not perfect, fit to the adiabatic curve. Arguments about the locality of functionals and convexity of the adiabatic connection curve are examined in this regime.Comment: 7 pages, 5 figure

Point Estimation of States of Finite Quantum Systems

The estimation of the density matrix of a $k$-level quantum system is studied when the parametrization is given by the real and imaginary part of the entries and they are estimated by independent measurements. It is established that the properties of the estimation procedure depend very much on the invertibility of the true state. In particular, in case of a pure state the estimation is less efficient. Moreover, several estimation schemes are compared for the unknown state of a qubit when one copy is measured at a time. It is shown that the average mean quadratic error matrix is the smallest if the applied observables are complementary. The results are illustrated by computer simulations.Comment: 16 pages, 5 figure

An enamel-painted glass bottle from a “Turkish pit” in Buda

The fragments of a high quality, enamel painted, blue glass bottle with the date 1671 on its shoulder were found in the Castle District of Buda, in a huge pit dated to the period of the Ottoman occupation. The shape of the object shows eastern influences, while its decoration is clearly western. The origin of the bottle is probably Transylvanian, based on its characteristics and a small group of parallels

Reactivation of the mitosis-promoting factor in postmitotic cardiomyocytes

Cardiomyocytes cease to divide shortly after birth and an irreversible cell cycle arrest is evident accompanied by the downregulation of cyclin-dependent kinase activities. To get a better understanding of the cardiac cell cycle and its regulation, the effect of functional recovery of the mitosis-promoting factor (MPF) consisting of cyclin B1 and the cyclin-dependent kinase Cdc2 was assessed in primary cultures of postmitotic ventricular adult rat cardiomyocytes ( ARC). Gene transfer into ARC was achieved using the adenovirus-enhanced transferrinfection system that was characterized by the absence of cytotoxic events. Simultaneous ectopic expression of wild-type versions of cyclin B1 and Cdc2 was sufficient to induce MPF activity. Reestablished MPF resulted in a mitotic phenotype, marked by an abnormal condensation of the nuclei, histone H3 phosphorylation and variable degree of decay of the contractile apparatus. Although a complete cell division was not observed, the results provided conclusive evidence that cell cycle-related events in postmitotic cardiomyocytes could be triggered by genetic intervention downstream of the G1/S checkpoint. This will be of importance to design novel strategies to overcome the proliferation arrest in adult cardiomyocytes

Fungal diversity in floral and honeydew honeys

Studying fungal diversity in various environmental samples provides us with valuable knowledge about the occurrence of fungi of medical and ecological importance. Moreover, fungal composition may also characterise well the botanical and geographical source of food products, such as the origin of the spore enriched honeydew honeys. Thereby, we identified a wide spectrum of fungi found in 100 of honey samples from various geographical sources – most of them were from Italy, Greece and Hungary. Our honeydew honeys had a higher mean of the number of spore types found in them than floral honeys had. Statistically significant differences in diversity were found regarding the botanical source (p = 1.29 × 10–9) and the climatic classification (p = 2.28 × 10–2) according to Kruskal– Wallis rank sum tests. Most frequently encountered genera included ubiquitous saprotrophic species (Alternaria, Cladosporium, Epicoccum nigrum, Stemphylium), both in floral and honeydew honeys. On the other hand, certain sooty moulds like Aureobasidium pullulans, Tripospermum and Capnobotrys were rather present in different types of honeydew honeys. Metschnikowia reukaufii, the nectar inhabiting yeast reached considerably high quantities in floral honey samples. Present findings encourage further studies on quantifying the occurrence and the indicator value of specific fungal elements in honey, concerning its origin

Note on Comparability of MicroCog Test Forms

This study investigated the differences between the Standard and Short forms of MicroCog by comparing Domain scores for a clinical sample of 351 substance abusers which gave a significant difference between scores on the Spatial Processing Domain. Implications for research and clinical use are discussed