Spontaneous Ratchet Effect in a Granular Gas

The spontaneous clustering of a vibrofluidized granular gas is employed to generate directed transport in two different compartmentalized systems: a "granular fountain" in which the transport takes the form of convection rolls, and a "granular ratchet" with a spontaneous particle current perpendicular to the direction of energy input. In both instances, transport is not due to any system-intrinsic anisotropy, but arises as a spontaneous collective symmetry breaking effect of many interacting granular particles. The experimental and numerical results are quantitatively accounted for within a flux model.Comment: 4 pages, 5 figures; Fig. 4 has been reduced in size and qualit

Potential impacts of genetic use restriction technologies (GURTs) on agrobiodiversity and agricultural production systems

Development and application of GURT as an appropriation mechanism may potentially have considerable impact on agriculture, the environment and the food security of rural areas in developing countries. Positive impacts may include increased investments in breeding as a result of increased intellectual property protection. Increased investments may contribute to higher yields and more advanced varieties, and thus to increased food production, a more sustainable production, and better consumer products. Potential negative impacts have been identified as well. These may require further discussion and close attention by regulatory authorities

Poincar\'{e} cycle of a multibox Ehrenfest urn model with directed transport

We propose a generalized Ehrenfest urn model of many urns arranged periodically along a circle. The evolution of the urn model system is governed by a directed stochastic operation. Method for solving an $N$-ball, $M$-urn problem of this model is presented. The evolution of the system is studied in detail. We find that the average number of balls in a certain urn oscillates several times before it reaches a stationary value. This behavior seems to be a peculiar feature of this directed urn model. We also calculate the Poincar\'{e} cycle, i.e., the average time interval required for the system to return to its initial configuration. The result can be easily understood by counting the total number of all possible microstates of the system.Comment: 10 pages revtex file with 7 eps figure

Longtitudinal electron beam diagnostics via upconversion of THz to visible radiation

Longitudinal electro-optic electron bunch diagnostics has been successfully applied at several accelerators. The electro-optic effect can be seen as an upconversion of the Coulomb field of the relativistic electron bunch (THz radiation) to the visible spectral range, where a variety of standard diagnostic tools are available. Standard techniques to characterise femtosecond optical laser pulses (auto- and cross-correlators) have led to the schemes that can measure electron bunch profiles with femtosecond resolution. These techniques require, however, well synchronized femtosecond laser pulses, in order to obtain the desired temporal resolution. Currently, we are exploring other electro-optic variants which require less advanced laser systems and will be more amenable to beam based longitudinal feedback applications. The first results of one such new scheme will be presented in this paper

Iron deficiency in heart failure:Mechanisms and pathophysiology

Iron is an essential micronutrient for a myriad of physiological processes in the body beyond erythropoiesis. Iron deficiency (ID) is a common comorbidity in patients with heart failure (HF), with a prevalence reaching up to 59% even in non-anaemic patients. ID impairs exercise capacity, reduces the quality of life, increases hospitalisation rate and mortality risk regardless of anaemia. Intravenously correcting ID has emerged as a promising treatment in HF as it has been shown to alleviate symptoms, improve quality of life and exercise capacity and reduce hospitalisations. However, the pathophysiology of ID in HF remains poorly characterised. Recognition of ID in HF triggered more research with the aim to explain how correcting ID improves HF status as well as the underlying causes of ID in the first place. In the past few years, significant progress has been made in understanding iron homeostasis by characterising the role of the iron-regulating hormone hepcidin, the effects of ID on skeletal and cardiac myocytes, kidneys and the immune system. In this review, we summarise the current knowledge and recent advances in the pathophysiology of ID in heart failure, the deleterious systemic and cellular consequences of ID

Dynamics of vibrofluidized granular gases in periodic structures

The behavior of a driven granular gas in a container consisting of $M$ connected compartments is studied employing a microscopic kinetic model. After obtaining the governing equations for the occupation numbers and the granular temperatures of each compartment we consider the various dynamical regimes. The system displays interesting analogies with the ordering processes of phase separating mixtures quenched below the their critical point. In particular, we show that below a certain value of the driving intensity the populations of the various compartments become unequal and the system clusterizes. Such a phenomenon is not instantaneous, but is characterized by a time scale, $\tau$, which follows a Vogel-Vulcher exponential behavior. On the other hand, the reverse phenomenon which involves the ``evaporation'' of a cluster due to the driving force is also characterized by a second time scale which diverges at the limit of stability of the cluster.Comment: 11 pages, 17 figure

Reduced chance of hearing loss associated with Therapeutic Drug Monitoring of Aminoglycosides in the treatment of Multidrug Resistant Tuberculosis

Item does not contain fulltextHearing loss and nephrotoxicity are associated with prolonged treatment duration and higher dosage of amikacin and kanamycin. In our tuberculosis center, we used therapeutic drug monitoring (TDM) targeting preset pharmacokinetic/pharmacodynamic (PK/PD) surrogate endpoints in an attempt to maintain efficacy while preventing (oto)toxicity. To evaluate this strategy, we retrospectively evaluated medical charts of tuberculosis (TB) patients treated with amikacin or kanamycin in the period from 2000 to 2012. Patients with culture-confirmed multiresistant or extensively drug-resistant tuberculosis (MDR/XDR-TB) receiving amikacin or kanamycin as part of their TB treatment for at least 3 days were eligible for inclusion in this retrospective study. Clinical data, including maximum concentration (Cmax), Cmin, and audiometry data, were extracted from the patients' medical charts. A total of 80 patients met the inclusion criteria. The mean weighted Cmax/MIC ratios obtained from 57 patients were 31.2 for amikacin and 12.3 for kanamycin. The extent of hearing loss was limited and correlated with the cumulative drug dose per kg of body weight during daily administration. At follow-up, 35 (67.3%) of all patients had successful outcome; there were no relapses. At a median dose of 6.5 mg/kg, a correlation was found between the dose per kg of body weight during daily dosing and the extent of hearing loss in dB at 8,000 Hz. These findings suggest that the efficacy at this lower dosage is maintained with limited toxicity. A randomized controlled trial should provide final proof of the safety and efficacy of TDM-guided use of aminoglycosides in MDR-TB treatment