A cholesky-based SGM-MLFMM for stochastic full-wave problems described by correlated random variables

In this letter, the multilevel fast multipole method (MLFMM) is combined with the polynomial chaos expansion (PCE)-based stochastic Galerkin method (SGM) to stochastically model scatterers with geometrical variations that need to be described by a set of correlated random variables (RVs). It is demonstrated how Cholesky decomposition is the appropriate choice for the RVs transformation, leading to an efficient SGM-MLFMM algorithm. The novel method is applied to the uncertainty quantification of the currents induced on a rough surface, being a classic example of a scatterer described by means of correlated RVs, and the results clearly demonstrate its superiority compared to the non-intrusive PCE methods and to the standard Monte Carlo method

Transport properties of a Bose-Einstein condensate with tunable interactions in the presence of a disordered or single defect potential

Bose-Einstein condensates (BECs) have proven to be remarkable systems with which to study some of the foundational models of condensed matter physics. The observation of a critical velocity for the breakdown of superfluidity in a BEC and the superfluid to Mott insulator transition observed in a BEC trapped by an optical lattice are but two examples of the, by now, dozens of exciting results in this field, which combines theoretical tools from condensed matter physics with state-of-the-art experimental techniques from ultra-cold atomic physics. However, any real condensed matter system has to contend with the effects of disorder, a phenomena notably absent in the inherently clean BEC systems. We have developed and implemented a way to add well characterized disorder in a controlled way to the otherwise clean BEC system using the light field from a laser speckle pattern. Using this system, we have investigated the effects of disorder or a single Gaussian defect, on the collective dipole motion of a BEC of 7Li in an optical trap. In addition, we perform transport experiments on a weakly interacting BEC expanding in a disordered one-dimensional atom wave-guide. We have observed that in such a system, the wave nature of matter can lead to spectacular and counterintuitive phenomena. Specifically, we verify that this system exhibits Anderson localization, a phenomena fundamentally resulting from the interference of multiply scattered matter waves. In such a state, the localized gas behaves as an insulator in a regime where it is classically expected to be conducting. We also present results of experiments regarding a repulsive BEC scattering from a semi-permeable, single defect potential. We investigate the transport properties of such a system with special emphasis on the velocity and defect strength dependent dissipation of the collective dipole motion of the BEC. Finally, we present the results of our experiments on the scattering properties of bright matter wave solitons. We have observed fragmentation of the soliton in a disordered potential as well as both splitting and recombination of a soliton after interacting with a single repulsive defect potential

Disparities in Beef Tapeworm Identification Rates in the Abattoirs of Gauteng Province, South Africa: A Descriptive Epidemiologic Study

Background Bovine Taenia saginata cysticercus infections (also called bovine cysticercosis or beef measles) is usually diagnosed in cattle only during post-mortem meat inspection. The aim of this study was to investigate the identification rates of these infections in and to identify predictors/determinants of variations in the identification rates in abattoirs in Gauteng province, South Africa. Methods Retrospective data for over 1.4 million cattle carcasses inspected in 26 abattoirs between January 2010 and December 2013 were used for the study. The identification rates (proportion of bovine Taenia saginata cysticercus positive carcasses) were computed and generalized estimating equations used to identify predictors/determinants of identification rates. Results The overall identification rate was 0.70% (95% CI: 0.45, 0.95). Significantly (p\u3c 0.05) lower rates were reported during summer (0.55%) than other seasons. Some geographic areas reported significantly (p\u3c0.05) higher rates than others. The identification rates in high throughput abattoirs was significantly (p\u3c0.05) higher (RR: 9.4; 95% CI: 4.7–19.1) than in low throughput abattoirs. Similarly, the identification rates among animals from feedlots were significantly (p\u3c0.05) higher (RR: 1.6; 95% CI: 1.7–3.5) than those from non-feedlot sources. No significant (p\u3e0.05) association was identified between identification rates and either the number of meat inspectors per abattoir or the provider of inspection services. Conclusion Although no significant association was found between identification rates and provider of inspection services, follow-up studies will need to be done to specifically investigate the potential conflict of interest arising from the fact that abattoir owners hire meat inspection services directly. Capture of abattoir surveillance data needs to include farm address and for each case to be reported separately. Finally, information on the type of identified cysts (alive or calcified) need to be collected to help better estimate risk to consumers. This study provides useful baseline data to guide future studies, surveillance and control efforts

Machine learning-based characterization of SNR in digital satellite communication links

Signals traveling through a Satellite Communication (SatCom) channel are subject to noise and interference effects, impacting their Signal-to-Noise ratio (SNR). Furthermore, non-linear distortion arising from the nonlinear characteristic of the amplifiers in the system also adversely impacts performance. Current state-of-the-art techniques estimate these effects by including a sequence of known pilot symbols in the transmitted signals. While robust, a downside of these approaches is that pilot symbols do not include useful information, thus introducing overhead. This paper presents a Machine Learning (ML) approach to characterize the SNR, using the received signal in the return link of SatCom systems, independent of the signal's distortion level and without relying on pilot symbols. The proposed technique is validated through a suitable application example: the characterization of SNR in a SatCom system using a 16-APSK modulation scheme

Making the case for reforming the I/O software stack of extreme-scale systems

This work was supported in part by the U.S. Department of Energy, Office of Science, Advanced Scientific Computing Research, under Contract No. DE-AC02-05CH11231. This research has been partially funded by the Spanish Ministry of Science and Innovation under grant TIN2010-16497 “Input/Output techniques for distributed and high-performance computing environments”. The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement number 328582

Calcium/calmodulin-dependent kinase II and nitric oxide synthase 1 dependent modulation of ryanodine receptors during β-adrenergic stimulation is restricted to the dyadic cleft.

In cardiac myocytes, β‐adrenergic stimulation enhances Ca2+ cycling through an integrated signalling cascade modulating L‐type Ca2+ channels (LTCCs), phospholamban and ryanodine receptors (RyRs). Ca2+/calmodulin‐dependent kinase II (CaMKII) and nitric oxide synthase 1 (NOS1) are proposed as prime mediators for increasing RyR open probability. We investigate whether this pathway is confined to the high Ca2+ microdomain of the dyadic cleft and thus to coupled RyRs. Pig ventricular myocytes are studied under whole‐cell voltage‐clamp and confocal line‐scan imaging with Fluo‐4 as a [Ca2+]i indicator. Following conditioning depolarizing pulses, spontaneous RyR activity is recorded as Ca2+ sparks, which are assigned to coupled and non‐coupled RyR clusters. Isoproterenol (ISO) (10 nm) increases Ca2+ spark frequency in both populations of RyRs. However, CaMKII inhibition reduces spark frequency in coupled RyRs only; NOS1 inhibition mimics the effect of CaMKII inhibition. Moreover, ISO induces the repetitive activation of coupled RyR clusters through CaMKII activation. Immunostaining shows high levels of CaMKII phosphorylation at the dyadic cleft. CaMKII inhibition reduces ICaL and local Ca2+ transients during depolarizing steps but has only modest effects on amplitude or relaxation of the global Ca2+ transient. In contrast, protein kinase A (PKA) inhibition reduces spark frequency in all RyRs concurrently with a reduction of sarcoplasmic reticulum Ca2+ content, Ca2+ transient amplitude and relaxation. In conclusion, CaMKII activation during β‐adrenergic stimulation is restricted to the dyadic cleft microdomain, enhancing LTCC‐triggered local Ca2+ release as well as spontaneous diastolic Ca2+ release whilst PKA is the major pathway increasing global Ca2+ cycling. Selective CaMKII inhibition may reduce potentially arrhythmogenic release without negative inotropy

Disparities in beef tapeworm identification rates in the abattoirs of Gauteng Province, South Africa : a descriptive epidemiologic study

BACKGROUND Bovine Taenia saginata cysticercus infections (also called bovine cysticercosis or beef measles) is usually diagnosed in cattle only during post-mortem meat inspection. The aim of this study was to investigate the identification rates of these infections in and to identify predictors/ determinants of variations in the identification rates in abattoirs in Gauteng province, South Africa. METHODS Retrospective data for over 1.4 million cattle carcasses inspected in 26 abattoirs between January 2010 and December 2013 were used for the study. The identification rates (proportion of bovine Taenia saginata cysticercus positive carcasses) were computed and generalized estimating equations used to identify predictors/determinants of identification rates. RESULTS The overall identification rate was 0.70% (95% CI: 0.45, 0.95). Significantly (p< 0.05) lower rates were reported during summer (0.55%) than other seasons. Some geographic areas reported significantly (p<0.05) higher rates than others. The identification rates in high throughput abattoirs was significantly (p<0.05) higher (RR: 9.4; 95% CI: 4.7–19.1) than in low throughput abattoirs. Similarly, the identification rates among animals from feedlots were significantly (p0.05) association was identified between identification rates and either the number of meat inspectors per abattoir or the provider of inspection services. CONCLUSION Although no significant association was found between identification rates and provider of inspection services, follow-up studies will need to be done to specifically investigate the potential conflict of interest arising from the fact that abattoir owners hire meat inspection services directly. Capture of abattoir surveillance data needs to include farm address and for each case to be reported separately. Finally, information on the type of identified cysts (alive or calcified) need to be collected to help better estimate risk to consumers. This study provides useful baseline data to guide future studies, surveillance and control efforts.http://www.plosone.orgam2016Paraclinical Science