Thermally damped linear compressional waves in a 2D solar coronal model

The high resolution observations (TRACE and SOHO) of waves in coronal structures have revealed a rapid damping of modes, sometimes their damping length being of the same order as their wavelength. The rapid damping of modes in coronal loops permits us to derive values for magnetic field and transport coefficients. In this contribution we study the damping of linear compressional waves considering a two-dimensional propagation in gravitationally stratified plasma in the presence of thermal conduction. By considering this 2D model, we show that the presence of an additional transversal motion has an important effect on the damping of the waves. This theoretical model allows as to conclude that the main effects influencing the damping of the waves are the degree of the transversal structuring and temperature

Sausage mode propagation in a thick magnetic flux tube

The aim of this paper is to model the propagation of slow magnetohydrodynamic (MHD) sausage waves in a thick expanding magnetic flux tube in the context of the quiescent (VAL-C) solar atmosphere. The propagation of these waves is found to be described by the Klein–Gordon equation. Using the governing MHD equations and the VAL-C atmosphere model we study the variation of the cut-off frequency along and across the magnetic tube guiding the waves. Due to the radial variation of the cut-off frequency the flux tubes act as low frequency filters for the waves

Using Synchronic and Diachronic Relations for Summarizing Multiple Documents Describing Evolving Events

In this paper we present a fresh look at the problem of summarizing evolving events from multiple sources. After a discussion concerning the nature of evolving events we introduce a distinction between linearly and non-linearly evolving events. We present then a general methodology for the automatic creation of summaries from evolving events. At its heart lie the notions of Synchronic and Diachronic cross-document Relations (SDRs), whose aim is the identification of similarities and differences between sources, from a synchronical and diachronical perspective. SDRs do not connect documents or textual elements found therein, but structures one might call messages. Applying this methodology will yield a set of messages and relations, SDRs, connecting them, that is a graph which we call grid. We will show how such a grid can be considered as the starting point of a Natural Language Generation System. The methodology is evaluated in two case-studies, one for linearly evolving events (descriptions of football matches) and another one for non-linearly evolving events (terrorist incidents involving hostages). In both cases we evaluate the results produced by our computational systems.Comment: 45 pages, 6 figures. To appear in the Journal of Intelligent Information System

New oral anticoagulants and their reversal agents

Atrial fibrillation is a commonly encountered pathology in medical practice, and its prevalence has shown a continuous rise over the past years. Atrial fibrillation has a significant impact on patients\u27 quality of life, not only due to the standard anticoagulant treatment with vitamin K antagonists that require close monitoring and dose adjustment, but also due to the fragile equilibrium between hemorrhagic and thrombotic risks. The introduction of new oral anticoagulants (NOACs) in the treatment guidelines for atrial fibrillation has improved the quality of life, as NOACs do not require close monitoring or dose adjustments. However, even if the safety profile of the NOACs regarding the hemorrhagic risk is superior to vitamin K antagonists, the problem raised by an unexpected hemorrhage (e.g. severe hemorrhage after an accident) and the need for efficient hemostasis in a chronic anticoagulated patient has remained unsolved. To find a solution for this problem, reversal agents for NOACs have been developed and tested, and two of them, idarucizumab and andexanet-alpha, have already been approved by the FDA, thus making NOACs increasingly appealing as a choice of anticoagulation treatment

Rolul terapiei ocupaţionale în funcţionalitatea mâinii la pacienţii cu leziuni traumatice ale nervilor periferici

Introducere: Mâna reprezintă cel mai complex segment al corpului, sub raport funcţional, recâştigarea abilităţilor la pacienţii cu traumatisme care interesează acest segment, fi ind adesea difi cilă. Obiective: Evidenţierea modului corect de evaluare a pacientului cu leziuni traumatice ale nervilor periferici,stabilirea unui program de recuperare în care să fi e evidenţiată importanţa şi rolul terapiei ocupaţionale în funcţionalitatea mâinii. Material şi metodă: Studiul s-a desfăşurat în perioada mai 2008 - februarie 2009, în clinicile de Recuperare Medicală şi Medicina Muncii ale Spitalului Clinic Judeţean de Urgenţă Craiova. Lotul a inclus 12 pacienţi ce prezentau leziuni traumatice ale nervilor periferici la nivelul mâinii, majoritatea pacienţilor at bărbaţi (doar 2 femei); vârsta medie de 49 ani; 58% provin din mediu urban; 7 pacienţi au afectată mâna dreaptă; 7 pacienţi prezintă traumatism de nerv median. Pacienţii au urmat un program de terapie ocupaţională cu durata de o lună, integrat celorlalte mijloace specifi ce tratamentului complex de recuperare. Rezultate: Pensa tridigitală s-a ameliorat după aplicarea programului de terapie ocupaţională, în fi nal obţinânduse un scor mediu de 1.58 faţă de scorul iniţial de 0.83%. Toţi pacienţii incluşi în studiu au avut pensa grosieră cel puţin schiţată. S-a obţinut ameliorarea durerii evaluată pe scala VAS de la o valore medie iniţială de 9.583 la o valoare medie fi nală de 6.833. Scorul de evaluare a ADL-urilor s-a ameliorat în medie cu 47.311%. Concluzie: Terapia ocupaţională constituie o parte importantǎ a programului de recuperare la pacienţii cu leziuni traumatice de nervi periferici, incluzând activitǎţile de autoîngrijire şi casnice

Dispersive shock waves in partially ionised plasmas

Compressional waves propagating in the partially ionised solar lower atmospheric plasmas can easily steepen into nonlinear waves, including shocks. Here we investigate the effect of weak dispersion generated by Hall currents perpendicular to the ambient magnetic field on the characteristics of shock waves. Our study will also focus on the interplay between weak dispersion and partial ionisation of the plasma. Using a multiple scale technique we derive the governing equation in the form of a Korteweg-de Vries-Burgers equation. The effect of weak dispersion on shock waves is obtained using a perturbation technique. The secular behaviour of second order terms is addressed with the help of a renormalisation technique. Our results show that dispersion modifies the characteristics of shock waves and this change is dependent also on the ionisation degree of the plasma. Dispersion can create short lived oscillations in the shocked plasma. The shock fronts become wider with the increase in the number of neutrals in the plasma

Mutation of daf‐2 extends lifespan via tissue‐specific effectors that suppress distinct life‐limiting pathologies

In aging Caenorhabditis elegans, as in higher organisms, there is more than one cause of death. C. elegans exhibit early death with a swollen, infected pharynx (P death), and later death with pharyngeal atrophy (p death). Interventions that alter lifespan can differentially affect frequency and timing of each type of death, generating complex survival curve shapes. Here, we use mortality deconvolution analysis to investigate how reduction of insulin/IGF-1 signaling (IIS), which increases lifespan (the Age phenotype), affects different forms of death. All daf-2 insulin/IGF-1 receptor mutants exhibit increased lifespan in the p subpopulation (p Age), while pleiotropic class 2 daf-2 mutants show an additional marked reduction in P death frequency. The latter is promoted by pharyngeal expression of the IIS-regulated DAF-16 FOXO transcription factor, and at higher temperature by reduced pharyngeal pumping rate. Pharyngeal DAF-16 also promotes p Age in class 2 daf-2 mutants, revealing a previously unknown role for the pharynx in the regulation of aging. Necropsy analysis of daf-2 interactions with the daf-12 steroid receptor implies that previously described opposing effects of daf-12 on daf-2 longevity are attributable to internal hatching of larvae, rather than complex interactions between insulin/IGF-1 and steroid signaling. These findings support the view that wild-type IIS acts through multiple distinct mechanisms which promote different life-limiting pathologies, each of which contribute to late-life mortality. This study further demonstrates the utility of mortality deconvolution analysis to better understand the genetics of lifespan

Forced oscillations of coronal loops driven by external EIT waves

Aims. We study the generation of transversal oscillations in coronal loops represented as a straight thin flux tube under the effect of an external driver modelling the global coronal EIT wave. We investigate how the generated oscillations depend on the nature of the driver, and the type of interaction between the two systems. Methods. We consider the oscillations of a magnetic straight cylinder with fixed-ends under the influence of an external driver modelling the force due to the global EIT wave. Given the uncertainties related to the nature of EIT waves, we first approximate the driver by an oscillatory force in time and later by a shock with a finite width. Results. Results show that for a harmonic driver the dominant period in the generated oscillation belongs to the driver. Depending on the period of driver, compared to the natural periods of the loop, a mixture of standing modes harmonics can be initiated. In the case of a non-harmonic driver (modelling a shock wave), the generated oscillations in the loop are the natural periods only. The amplitude of oscillations is determined by the position of the driver along the tube. The full diagnosis of generated oscillations is achieved using simple numerical methods

Forced oscillations of coronal loops driven by external EIT waves

Aims. We study the generation of transversal oscillations in coronal loops represented as a straight thin flux tube under the effect of an external driver modelling the global coronal EIT wave. We investigate how the generated oscillations depend on the nature of the driver, and the type of interaction between the two systems. Methods. We consider the oscillations of a magnetic straight cylinder with fixed-ends under the influence of an external driver modelling the force due to the global EIT wave. Given the uncertainties related to the nature of EIT waves, we first approximate the driver by an oscillatory force in time and later by a shock with a finite width. Results. Results show that for a harmonic driver the dominant period in the generated oscillation belongs to the driver. Depending on the period of driver, compared to the natural periods of the loop, a mixture of standing modes harmonics can be initiated. In the case of a non-harmonic driver (modelling a shock wave), the generated oscillations in the loop are the natural periods only. The amplitude of oscillations is determined by the position of the driver along the tube. The full diagnosis of generated oscillations is achieved using simple numerical methods

Predictive models of tumour response to treatment using functional imaging techniques

Editorial, abstract not included.Loredana G. Marcu, Eva Bezak, Iuliana Toma-Dasu, and Alexandru Das