482 research outputs found
PFAS River Export Analysis Highlights the Urgent Need for Catchment-Scale Mass Loading Data
Source apportionment of per-and polyfluoroalkyl substances (PFAS) requires an understanding of the mass loading of these compounds in river basins. However, there is a lack of temporally variable and catchment-scale mass loading data, meaning identification and prioritization of sources of PFAS to rivers for management interventions can be difficult. Here, we analyze PFAS concentrations and loads in the River Mersey to provide the first temporally robust estimates of PFAS export for a European river system and the first estimates of the contribution of wastewater treatment works (WwTWs) to total river PFAS export. We estimate an annual PFAS export of 68.1 kg for the River Mersey and report that the yield of perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in the catchment is among the highest recorded globally. Analysis of river and WwTW loads indicates approximately one-third of PFOA emitted from WwTWs is potentially stored in the catchment and approximately half of PFOS transported by the River Mersey may not originate from WwTWs. As governments move toward regulation of PFAS in WwTW effluents, our findings highlight the complexity of PFAS source apportionment and the need for catchment-scale mass loading data. This study indicates that strategies for reducing PFAS loading that focus solely on WwTW effluents may not achieve river water quality targets
Twisted boundary states in c=1 coset conformal field theories
We study the mutual consistency of twisted boundary conditions in the coset
conformal field theory G/H. We calculate the overlap of the twisted boundary
states of G/H with the untwisted ones, and show that the twisted boundary
states are consistently defined in the diagonal modular invariant. The overlap
of the twisted boundary states is expressed by the branching functions of a
twisted affine Lie algebra. As a check of our argument, we study the diagonal
coset theory so(2n)_1 \oplus so(2n)_1/so(2n)_2, which is equivalent with the
orbifold S^1/\Z_2. We construct the boundary states twisted by the
automorphisms of the unextended Dynkin diagram of so(2n), and show their mutual
consistency by identifying their counterpart in the orbifold. For the triality
of so(8), the twisted states of the coset theory correspond to neither the
Neumann nor the Dirichlet boundary states of the orbifold and yield the
conformal boundary states that preserve only the Virasoro algebra.Comment: 44 pages, 1 figure; (v2) minor change in section 2.3, references
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Influence of damping on the excitation of the double giant resonance
We study the effect of the spreading widths on the excitation probabilities
of the double giant dipole resonance. We solve the coupled-channels equations
for the excitation of the giant dipole resonance and the double giant dipole
resonance. Taking Pb+Pb collisions as example, we study the resulting effect on
the excitation amplitudes, and cross sections as a function of the width of the
states and of the bombarding energy.Comment: 8 pages, 3 figures, corrected typo
From boundary to bulk in logarithmic CFT
The analogue of the charge-conjugation modular invariant for rational
logarithmic conformal field theories is constructed. This is done by
reconstructing the bulk spectrum from a simple boundary condition (the analogue
of the Cardy `identity brane'). We apply the general method to the c_1,p
triplet models and reproduce the previously known bulk theory for p=2 at c=-2.
For general p we verify that the resulting partition functions are modular
invariant. We also construct the complete set of 2p boundary states, and
confirm that the identity brane from which we started indeed exists. As a
by-product we obtain a logarithmic version of the Verlinde formula for the
c_1,p triplet models.Comment: 35 pages, 2 figures; v2: minor corrections, version to appear in
J.Phys.
Rectangular amplitudes, conformal blocks, and applications to loop models
In this paper we continue the investigation of partition functions of
critical systems on a rectangle initiated in [R. Bondesan et al,
Nucl.Phys.B862:553-575,2012]. Here we develop a general formalism of rectangle
boundary states using conformal field theory, adapted to describe geometries
supporting different boundary conditions. We discuss the computation of
rectangular amplitudes and their modular properties, presenting explicit
results for the case of free theories. In a second part of the paper we focus
on applications to loop models, discussing in details lattice discretizations
using both numerical and analytical calculations. These results allow to
interpret geometrically conformal blocks, and as an application we derive new
probability formulas for self-avoiding walks.Comment: 46 page
Status of the Frankfurt 14 GHz-ECRIS-(ve)RFQ Facility
The accelerator facility installed at the Institut fuer Kernphysik (IKF) combines a 14 GHz electron cyclotron resonance ion source (ECRIS) and a variable energy radio frequency quadrupole accelerator (ve-RFQ)[1,2]. The provided highly charged ions have an energy range between a few keV - using the beam delivered from the source - up to 200 keV/u by using the post acceleration of the ve-RFQ. The setup is designed to deliver a wide spectrum of ions in sufficiently high charged states for atomic physics and materials research. Besides this the ion source is used for studies of the production of highly charged ions with the intention to improve quality and intensity of ion beams. In addition to these activities there are some special topics which deal with the investigation of phenomena on the ECRIS plasma and the production of metal ions by laser ablation technique (see also contributions to this workshop S. Runkel et al. And V. Mironov et. al). The present status and further activities of the facility and a view of the different projects will be reported
Synoptic sampling and principal components analysis to identify sources of water and metals to an acid mine drainage stream
Combining the synoptic mass balance approach with principal components analysis (PCA) can be an effective method for discretising the chemistry of inflows and source areas in watersheds where contamination is diffuse in nature and/or complicated by groundwater interactions. This paper presents a field-scale study in which synoptic sampling and PCA are employed in a mineralized watershed (Lion Creek, Colorado, USA) under low flow conditions to (i) quantify the impacts of mining activity on stream water quality; (ii) quantify the spatial pattern of constituent loading; and (iii) identify inflow sources most responsible for observed changes in stream chemistry and constituent loading. Several of the constituents investigated (Al, Cd, Cu, Fe, Mn, Zn) fail to meet chronic aquatic life standards along most of the study reach. The spatial pattern of constituent loading suggests four primary sources of contamination under low flow conditions. Three of these sources are associated with acidic (pH <3.1) seeps that enter along the left bank of Lion Creek. Investigation of inflow water (tracemetal and major ion) chemistry using PCA suggests a hydraulic connection between many of the left bank inflows and mine water in the Minnesota Mine shaft located to the north-east of the river channel. In addition, water chemistry data during a rainfall-runoff event suggests the spatial pattern of constituent loading may be modified during rainfall due to dissolution of efflorescent salts or erosion of streamside tailings. These data point to the complexity of contaminant mobilisation processes and constituent loading in mining-affected watersheds but the combined synoptic sampling and PCA approach enables a conceptual model of contaminant dynamics to be developed to inform remediation
Unilateral Ovarian Abscess Caused by Salmonella
Background: Patients with unilateral ovarian abscesses due to Salmonella are rare. Case report: A 48-year-old woman with a left ovarian abscess caused by Salmonella group O7 is reported. Conclusion: In our patient, the ovary may have been seeded hematogenously by salmonellae and may have evolved into a local infection
AQFT from n-functorial QFT
There are essentially two different approaches to the axiomatization of
quantum field theory (QFT): algebraic QFT, going back to Haag and Kastler, and
functorial QFT, going back to Atiyah and Segal. More recently, based on ideas
by Baez and Dolan, the latter is being refined to "extended" functorial QFT by
Freed, Hopkins, Lurie and others. The first approach uses local nets of
operator algebras which assign to each patch an algebra "of observables", the
latter uses n-functors which assign to each patch a "propagator of states".
In this note we present an observation about how these two axiom systems are
naturally related: we demonstrate under mild assumptions that every
2-dimensional extended Minkowskian QFT 2-functor ("parallel surface transport")
naturally yields a local net. This is obtained by postcomposing the propagation
2-functor with an operation that mimics the passage from the Schroedinger
picture to the Heisenberg picture in quantum mechanics.
The argument has a straightforward generalization to general
pseudo-Riemannian structure and higher dimensions.Comment: 39 pages; further examples added: Hopf spin chains and asymptotic
inclusion of subfactors; references adde
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