Stochastic embedding DFT: theory and application to p-nitroaniline

Over this past decade, we combined the idea of stochastic resolution of identity with a variety of electronic structure methods. In our stochastic Kohn-Sham DFT method, the density is an average over multiple stochastic samples, with stochastic errors that decrease as the inverse square root of the number of sampling orbitals. Here we develop a stochastic embedding density functional theory method (se-DFT) that selectively reduces the stochastic error (specifically on the forces) for a selected sub-system(s). The motivation, similar to that of other quantum embedding methods, is that for many systems of practical interest the properties are often determined by only a small sub-system. In stochastic embedding DFT two sets of orbitals are used: a deterministic one associated with the embedded subspace, and the rest which is described by a stochastic set. The method is exact in the limit of large number of stochastic samples. We apply se-DFT to study a p-nitroaniline molecule in water, where the statistical errors in the forces on the system (the p-nitroaniline molecule) are reduced by an order of magnitude compared with non-embedding stochastic DFT

Multiscale simulations in simple metals: a density-functional based methodology

We present a formalism for coupling a density functional theory-based quantum simulation to a classical simulation for the treatment of simple metallic systems. The formalism is applicable to multiscale simulations in which the part of the system requiring quantum-mechanical treatment is spatially confined to a small region. Such situations often arise in physical systems where chemical interactions in a small region can affect the macroscopic mechanical properties of a metal. We describe how this coupled treatment can be accomplished efficiently, and we present a coupled simulation for a bulk aluminum system.Comment: 15 pages, 7 figure

Elevated CO2 did not stimulate stem growth in 11 provenances of a globally important hardwood plantation species

Elevated atmospheric carbon dioxide (eCO2) often enhances rates of photosynthesis leading to increased productivity in trees. In their native habitats in Australia, eucalypts display considerable phenotypic plasticity in response to changes in environmental conditions. Little is known whether this plasticity can be harnessed effectively under future atmospheric eCO2 conditions and be used to identify provenances with superior growth. Here, we report two experiments that assessed the physiological and growth responses of Eucalyptus grandis—one of the world's most important hardwood plantation species—to eCO2. We used 11 provenances from contrasting climates. Our selection was based on site-specific information of long-term temperature and water availability. In Experiment 1, four provenances exhibited significant variation in light-saturated photosynthetic rates (Asat), stomatal conductance (gs), and concentrations of non-structural carbohydrates in leaves, stems and roots when grown under ambient CO2 (aCO2). Biomass of leaves, stems and roots varied significantly and were negatively correlated with mean annual temperature (MAT) at seed origin, indicating that provenances from cooler, wetter climates generally produced greater biomass. Yet, stem growth of these provenances was not stimulated by eCO2. Given the vast environmental gradient covered by provenances of E. grandis, we expanded the selection from four to nine provenances in Experiment 2. This allowed us to validate results from Experiment 1 with its small selection and detailed measurements of various physiological parameters by focusing on growth responses to eCO2 across a wider environmental gradient in Experiment 2. In Experiment 2, nine provenances also exhibited intraspecific differences in growth, but these were not related to climate of origin, and eCO2 had little effect on growth traits. Growth responses under eCO2 varied widely across provenances in both experiments, confirming phenotypic plasticity in E. grandis, though responses were not systematically correlated with climate of origin. These results indicate that selection of provenances for improved stem growth of E. grandis under future eCO2 cannot be based solely on climate of origin, as is common practice for other planted tree species

Detailed Analysis of Transverse Emittance of the FLUTE Electron Bunch

The com­pact and ver­sa­tile lin­ear ac­cel­er­a­tor-based test fa­cil­ity FLUTE (Fer­n­in­frarot Linac- Und Test-Ex­per­i­ment) is op­er­ated at KIT. Its pri­mary goal is to serve as a plat­form for a va­ri­ety of ac­cel­er­a­tor R\&D stud­ies like the gen­er­a­tion of strong ul­tra-short ter­a­hertz pulses. The am­pli­tude of the gen­er­ated co­her­ent THz pulses is pro­por­tional to the square num­ber of par­ti­cles in the bunch. With the trans­verse emit­tance a mea­sure for the trans­verse par­ti­cle den­sity can be de­ter­mined. It is there­fore a vital pa­ra­me­ter in the op­ti­miza­tion for op­er­a­tion. In a sys­tem­atic study, the trans­verse emit­tance of the elec­tron beam was mea­sured in the FLUTE in­jec­tor. A de­tailed analy­sis con­sid­ers dif­fer­ent in­flu­ences such as the bunch charge and com­pares this with par­ti­cle track­ing sim­u­la­tions car­ried out with ASTRA. In this con­tri­bu­tion, the key find­ings of this analy­sis are dis­cussed

CELL-LINED, NONWOVEN MICROFIBER SCAFFOLDS AS A BLOOD INTERFACE *

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73137/1/j.1749-6632.1977.tb41787.x.pd

Thermodynamic properties of spontaneous magnetization in Chern-Simons QED_3

The spontaneous magnetization in Chern-Simons QED_3 is discussed in a finite temperature system. The thermodynamical potential is analyzed within the weak field approximation and in the fermion massless limit. We find that there is a linear term with respect to the magnetic field with a negative coefficient at any finite temperature. This implies that the spontaneous magnetic field does not vanish even at high temperature. In addition, we examine the photon spectrum in the system. We find that the bare Chern-Simons coefficient is cancelled by the radiative effects. The photons then become topologically massless according to the magnetization, though they are massive by finite temperature effects. Thus the magnetic field is a long-range force without the screening even at high temperature.Comment: 32 pages, Latex, 4 eps figure

Radiation Safety at FLUTE with Special Emphasis on Activation Issues

The accelerator FLUTE (name abbreviation derived from its German name: Ferninfrarot Linac- und TestExperiment) has been set up in cooperation with DESY and PSI [1]. The electron source and diagnostics has commenced operation. General safety issues of FLUTE are covered in this paper. The activation of the accelerator and vacuum parts were predicted previously [2]. The attention is given to the activation of aluminum and impurities in the electron absorber of the beam dump. Potential air activation in the experimental hall is also discussed

Mobile Phone Data for Children on the Move: Challenges and Opportunities

Today, 95% of the global population has 2G mobile phone coverage and the number of individuals who own a mobile phone is at an all time high. Mobile phones generate rich data on billions of people across different societal contexts and have in the last decade helped redefine how we do research and build tools to understand society. As such, mobile phone data has the potential to revolutionize how we tackle humanitarian problems, such as the many suffered by refugees all over the world. While promising, mobile phone data and the new computational approaches bring both opportunities and challenges. Mobile phone traces contain detailed information regarding people's whereabouts, social life, and even financial standing. Therefore, developing and adopting strategies that open data up to the wider humanitarian and international development community for analysis and research while simultaneously protecting the privacy of individuals is of paramount importance. Here we outline the challenging situation of children on the move and actions UNICEF is pushing in helping displaced children and youth globally, and discuss opportunities where mobile phone data can be used. We identify three key challenges: data access, data and algorithmic bias, and operationalization of research, which need to be addressed if mobile phone data is to be successfully applied in humanitarian contexts.Comment: 13 pages, book chapte

Assessment of adipokines, adenine nucleotides and uric acid in the dynamics of coronary intervention

Introduction: The association of vaspin and visfatin, with a myocardial infarction is still not fully understood. Reduced levels of adenine nucleotides are hallmarks of chronic heart failure. There is little data concerning the relationship between these markers and their changes over time. Material/Methods: The concentration of adenine nucleotides, vaspin and visfatinwere assessed in 41 consecutive patients with acute myocardial infarction one before (day I) and four days after (day IV) percutaneous coronary intervention (PCI) and a control group. Results: Visfatin concentrations were higher before and after PCI vs. control (visfatin I: median 25.55, 20.12 - 30.69 ng/ml; visfatin IV: median 20.79, 16.89 - 25.61 ng/ml vs. control: median 14.94, 10.66 - 25.25 ng/ml; p < 0.0001). Vaspin concentrations were lower before and after PCI vs. control (vaspin I: median 0.18, 0.11 - 0.44 ng/ml; vaspin IV: median 0.24, 0.15 - 0.58 ng/ml vs. control: median 1.303, 1.13 - 2.26 ng/ml, p < 0.00001). Concentrations of visfatin, day I, correlated well to vaspin concentrations (r2 = 0.201, p = 0.011). ATP levels were significantly lower in patients vs. controls (day I: p = 0.00012; day IV: p = 0.0001). Conclusions: Changes in the analyzed visfatin and vaspin concentrations can be used as potential MI markers. Visfatin serum concentration may be considered a potential marker to differentiate MI over time

False-Positive Human Immunodeficiency Virus Enzyme Immunoassay Results in Pregnant Women

Objective: Examine whether false-positive HIV enzyme immunoassay (EIA) test results occur more frequently among pregnant women than among women who are not pregnant and men (others). Design: To obtain a large number of pregnant women and others tested for HIV, we identified specimens tested at a national laboratory using Genetic Systems HIV-1/HIV-2 Plus O EIA from July 2007 to June 2008. Methods: Specimens with EIA repeatedly reactive and Western blot-negative or indeterminate results were considered EIA false-positive. We compared the false-positive rate among uninfected pregnant women and others, adjusting for HIV prevalence. Among all reactive EIAs, we evaluated the proportion of false-positives, positive predictive value (PPV), and Western blot bands among indeterminates, by pregnancy status. Results: HIV prevalence was 0.06 % among 921,438 pregnant women and 1.34 % among 1,103,961 others. The false-positive rate was lower for pregnant women than others (0.14 % vs. 0.21%, odds ratio 0.65 [95 % confidence interval 0.61, 0.70]). Pregnant women with reactive EIAs were more likely than others (p,0.01) to have Western blot-negative (52.9 % vs. 9.8%) and indeterminate results (17.0 % vs. 3.7%) and lower PPV (30 % vs. 87%). The p24 band was detected more often among pregnant women (p,0.01). Conclusions: False-positive HIV EIA results were rare and occurred less frequently among pregnant women than others