The Diamine Cation Is Not a Chemical Example Where Density Functional Theory Fails

In a recent communication, Weber and co-workers presented a surprising study on charge-localization effects in the N,N'-dimethylpiperazine (DMP+) diamine cation to provide a stringent test of density functional theory (DFT) methods. Within their study, the authors examined various DFT methods and concluded that "all DFT functionals commonly used today, including hybrid functionals with exact exchange, fail to predict a stable charge-localized state." This surprising conclusion is based on the authors' use of a self-interaction correction (namely, complex-valued Perdew-Zunger Self-Interaction Correction (PZ-SIC)) to DFT, which appears to give excellent agreement with experiment and other wavefunction-based benchmarks. Since the publication of this recent communication, the same DMP+ molecule has been cited in numerous subsequent studies as a prototypical example of the importance of self-interaction corrections for accurately calculating other chemical systems. In this correspondence, we have carried out new high-level CCSD(T) analyses on the DMP+ cation to show that DFT actually performs quite well for this system (in contrast to their conclusion that all DFT functionals fail), whereas the PZ-SIC approach used by Weber et al. is the outlier that is inconsistent with the high-level CCSD(T) (coupled-cluster with single and double excitations and perturbative triples) calculations. Our new findings and analysis for this system are briefly discussed in this correspondence.Comment: Accepted by Nature Communication

Absorption and Emission in the non-Poisson case

This letter adresses the challenging problems posed to the Kubo-Anderson (KA) theory by the discovery of intermittent resonant fluorescence with a non-exponential distribution of waiting times. We show how to extend the KA theory from aged to aging systems, aging for a very extended time period or even forever, being a crucial consequence of non-Poisson statistics.Comment: 4 pages 3 figures. accepted for publication on Physical Review Letter

Predictors of Missed Hepatitis C Intake Appointments and Failure to Establish Hepatitis C Care Among Patients Living With HIV.

BackgroundWe estimated and characterized the proportion of patients living with HIV (PLWH) who missed hepatitis C (HCV) intake appointments and subsequently failed to establish HCV care.MethodsLogistic regression analyses were used to identify factors associated with missed HCV intake appointments and failure to establish HCV care among PLWH referred for HCV treatment between January 2014 and December 2017. In addition to demographics, variables included HIV treatment characteristics, type of insurance, liver health status, active alcohol or illicit drug use, unstable housing, and history of a mental health disorder (MHD).ResultsDuring the study period, 349 new HCV clinic appointments were scheduled for 202 unduplicated patients. Approximately half were nonwhite, and 80% had an undetectable HIV viral load. Drug use (31.7%), heavy alcohol use (32.8%), and MHD (37.8%) were prevalent. Over the 4-year period, 21.9% of PLWH referred for HCV treatment missed their HCV intake appointment. The proportion increased each year, from 17.2% in 2014 to 25.4% in 2017 (P = .021). Sixty-six of the 202 newly referred HCV patients (32.7%) missed their first HCV appointment, and 28 of these (42.4%) failed to establish HCV care. Having a history of MHD, CD4 <200, ongoing drug use, and being nonwhite were independent predictors of missing an intake HCV appointment. The strongest predictor of failure to establish HCV care was having a detectable HIV viral load.ConclusionsThe proportion of PLWH with missed HCV appointments increased over time. HCV elimination among PLWH may require integrated treatment of MHD and substance use

The useful potential of using existing data to uniquely identify predictable wind events and regimes, part 1

Correlations between standard meteorological data and wind power generation potential were developed. Combined with appropriate wind forecasts, these correlations can be useful to load dispatchers to supplement conventional energy sources. Hourly wind data were analyzed for four sites, each exhibiting a unique physiography. These sites are Amarillo, Texas; Ludington, Michigan; Montauk Point, New York; and San Gorgonio, California. Synoptic weather maps and tables are presented to illustrate various wind 'regimes' at these sites

AMERICANS AND GM FOOD: KNOWLEDGE, OPINION AND INTEREST IN 2004

This report presents the results from the third in a series of studies examining public perception of genetically modified (GM) food in the United States. All three studies were based on survey results of separate, nationally representative samples of approximately 1,200 Americans taken in 2001, 2003, and 2004. While the survey instrument on which the current report is based maintained many of the same measures of awareness and attitude as its two predecessors, it also included several new queries that assess the ability of respondents to recall specific news stories related to GM food, their interest in the topic, and where they would go to look for new information. Many questions that were repeated from previous years have changed considerably in the current survey. Some of the classic measures of awareness and opinion now incorporate an "unsure" response as choice supplied by the interviewer. While respondents were allowed to volunteer this response in the past, explicitly providing this option to respondents reduced guessing on knowledge-based questions and encouraged a more accurate representation of opinion than in the past. The report begins with an investigation of Americans' awareness and knowledge about the topic in general, their ability to recall related news stories, familiarity with laws and regulations as well as other questions designed to get at highly specific knowledge about agricultural biotechnology. Next, it details the effect of the new survey methodology on reported opinions about plant-based and animal-based GM food. Finally, it delves into a number of novel findings about interest in hypothetical television shows about GM food, desire for information on food labels, and reported behavior with regards to information seeking. Consistent with results from our previous studies and others, these findings suggest that the American public is generally unaware of GM food. Most Americans have heard or read little about it, are not aware of its prevalence in their lives, and are confused as to which type of GM products are available. Respondents struggled with factual questions related to GM food and the science behind it, could not recall news stories related to the topic, and were not very knowledgeable about laws regarding the labeling and testing of GM food. Americans are also unsure of their opinions about GM food and split in their assessments of the technology when forced to take a position. Americans say they are interested in the topic of GM food, specifically those topics related to human health. Respondents say they desire more information on food labels and report that they would like to see GM foods labeled as such. The majority of Americans admit they have never looked for information about GM food and most say they will search the Internet should the need arise.Research and Development/Tech Change/Emerging Technologies,

Aging and Rejuvenation with Fractional Derivatives

We discuss a dynamic procedure that makes the fractional derivatives emerge in the time asymptotic limit of non-Poisson processes. We find that two-state fluctuations, with an inverse power-law distribution of waiting times, finite first moment and divergent second moment, namely with the power index mu in the interval 2<mu <3, yields a generalized master equation equivalent to the sum of an ordinary Markov contribution and of a fractional derivative term. We show that the order of the fractional derivative depends on the age of the process under study. If the system is infinitely old, the order of the fractional derivative, ord, is given by ord=3-mu . A brand new system is characterized by the degree ord=mu -2. If the system is prepared at time -ta<0$ and the observation begins at time t=0, we derive the following scenario. For times 0<t<<ta the system is satisfactorily described by the fractional derivative with ord=3-mu . Upon time increase the system undergoes a rejuvenation process that in the time limit t>>ta yields ord=mu -2. The intermediate time regime is probably incompatible with a picture based on fractional derivatives, or, at least, with a mono-order fractional derivative.Comment: 11 pages, 4 figure

Brownian motion of a charged particle driven internally by correlated noise

We give an exact solution to the generalized Langevin equation of motion of a charged Brownian particle in a uniform magnetic field that is driven internally by an exponentially-correlated stochastic force. A strong dissipation regime is described in which the ensemble-averaged fluctuations of the velocity exhibit transient oscillations that arise from memory effects. Also, we calculate generalized diffusion coefficients describing the transport of these particles and briefly discuss how they are affected by the magnetic field strength and correlation time. Our asymptotic results are extended to the general case of internal driving by correlated Gaussian stochastic forces with finite autocorrelation times.Comment: 10 pages, 4 figures with subfigures, RevTeX, v2: revise

Correlation function and generalized master equation of arbitrary age

We study a two-state statistical process with a non-Poisson distribution of sojourn times. In accordance with earlier work, we find that this process is characterized by aging and we study three different ways to define the correlation function of arbitrary age of the corresponding dichotomous fluctuation based respectively on the Generalized Master Equation formalism, on a Liouville-like approach and on a trajectory perspective.Comment: 11 pages, 1figur