394 research outputs found
The fate of bezafibrate, carbamazepine, ciprofloxacin and clarithromycin in the wastewater treatment process
The progress of four pharmaceuticals (bezafibrate, carbamazepine, clarithromycin and ciprofloxacin) is followed through the treatment stages (screened sewage, settled sewage and final effluent) of a large urban wastewater treatment plant (WWTP) employing activated sludge treatment. Concentrations at the inlet to the WWTP are generally higher than those predicted from consideration of local pharmaceutical consumption and typical excretion data. Percentage removal efficiencies are variable (22.5 – 94.3%) with carbamazepine being the most resistant to elimination
Measuring National Mood with Music: Using Machine Learning to Construct a Measure of National Valence from Audio Data
We propose a new measure of national valence based on the emotional content of a country’s most popular songs. We first trained a machine learning model using 191 different audio features embedded within music and use this model to construct a long-run valence index for the UK. This index correlates strongly and significantly with survey-based life satisfaction and outperforms an equivalent text-based measure. Our methods have the potential to be applied widely and to provide a solution to the severe lack of historical time-series data on psychological well-being
Sources and pathways for pharmaceuticals in the urban water environment
The progress of five pharmaceutical compounds (bezafibrate, carbamazepine, diclofenac, ibuprofen and sulfasalazine) and one antibacterial agent (triclosan) were monitored through the treatment stages of a large sewage treatment works (STW) using activated sludge as well as in the receiving water both upstream and downstream of the effluent discharge. All except sulfasalazine were detected in the influent at concentrations ranging from 1.44-3.75 µg/L. The analysis of prescription data has been used as a tool to predict the amount of pharmaceuticals potentially released into the catchment of the investigated sewage treatment works and the results compared with the measured influent concentrations. A reduction in concentration between influent and final effluent samples (51-97%) indicates the variable removal of these compounds and therefore their potential to be discharged into receiving surface waters. The analysis of primary and final effluents highlight the important processes involved in the removal of pharmaceuticals and indicate that sorption processes are important for bezafibrate, carbamazepine and diclofenac. These three PPCPs were observed at higher concentrations (0.07-0.35 µg/L) downstream of the discharged effluent compared to upstream (0.02-0.04 µg/L) although the risks that these compounds pose in the environment are not yet fully understood
The quality of fibre grown by Australian alpacas : part 2 : survey of the quality of fibre grown by Australian alpacas
Noise Induced Complexity: From Subthreshold Oscillations to Spiking in Coupled Excitable Systems
We study stochastic dynamics of an ensemble of N globally coupled excitable
elements. Each element is modeled by a FitzHugh-Nagumo oscillator and is
disturbed by independent Gaussian noise. In simulations of the Langevin
dynamics we characterize the collective behavior of the ensemble in terms of
its mean field and show that with the increase of noise the mean field displays
a transition from a steady equilibrium to global oscillations and then, for
sufficiently large noise, back to another equilibrium. Diverse regimes of
collective dynamics ranging from periodic subthreshold oscillations to
large-amplitude oscillations and chaos are observed in the course of this
transition. In order to understand details and mechanisms of noise-induced
dynamics we consider a thermodynamic limit of the ensemble, and
derive the cumulant expansion describing temporal evolution of the mean field
fluctuations. In the Gaussian approximation this allows us to perform the
bifurcation analysis; its results are in good agreement with dynamical
scenarios observed in the stochastic simulations of large ensembles
Singularity Structure, Symmetries and Integrability of Generalized Fisher Type Nonlinear Diffusion Equation
In this letter, the integrability aspects of a generalized Fisher type
equation with modified diffusion in (1+1) and (2+1) dimensions are studied by
carrying out a singularity structure and symmetry analysis. It is shown that
the Painlev\'e property exists only for a special choice of the parameter
(). A B\"acklund transformation is shown to give rise to the linearizing
transformation to the linear heat equation for this case (). A Lie
symmetry analysis also picks out the same case () as the only system among
this class as having nontrivial infinite dimensional Lie algebra of symmetries
and that the similarity variables and similarity reductions lead in a natural
way to the linearizing transformation and physically important classes of
solutions (including known ones in the literature), thereby giving a group
theoretical understanding of the system. For nonintegrable cases in (2+1)
dimensions, associated Lie symmetries and similarity reductions are indicated.Comment: 8 page
An Australian Alpaca research project : productivity and marketing improvement of the Alpaca fibre industry in Australia : some preliminary data
Generalized Rate-Code Model for Neuron Ensembles with Finite Populations
We have proposed a generalized Langevin-type rate-code model subjected to
multiplicative noise, in order to study stationary and dynamical properties of
an ensemble containing {\it finite} neurons. Calculations using the
Fokker-Planck equation (FPE) have shown that owing to the multiplicative noise,
our rate model yields various kinds of stationary non-Gaussian distributions
such as gamma, inverse-Gaussian-like and log-normal-like distributions, which
have been experimentally observed. Dynamical properties of the rate model have
been studied with the use of the augmented moment method (AMM), which was
previously proposed by the author with a macroscopic point of view for
finite-unit stochastic systems. In the AMM, original -dimensional stochastic
differential equations (DEs) are transformed into three-dimensional
deterministic DEs for means and fluctuations of local and global variables.
Dynamical responses of the neuron ensemble to pulse and sinusoidal inputs
calculated by the AMM are in good agreement with those obtained by direct
simulation. The synchronization in the neuronal ensemble is discussed.
Variabilities of the firing rate and of the interspike interval (ISI) are shown
to increase with increasing the magnitude of multiplicative noise, which may be
a conceivable origin of the observed large variability in cortical neurons.Comment: 19 pages, 9 figures, accepted in Phys. Rev. E after minor
modification
- …