420 research outputs found
Improving Detection of Events at Water Treatment Works: A UK Case Study
This is the author accepted manuscriptThis study presents improvements to the event detection capabilities of the existing, thresholdbased detection system used by United Utilities in one of their Water Treatment Works. These improvements
were achieved by using new threshold and persistence values identified by performing a sensitivity type
analysis. The findings from this study show that, although an overall increase in the true detection rate and
decrease in the number of false alarms were achieved, the high number of false alarms remains an issue
Spherical-box approach for resonances in presence of Coulomb interaction
The spherical-box approach is extended to calculate the resonance parameters
and the real part of the wave function for single particle resonances in a
potential containing the long-range Coulomb interaction. A model potential is
taken to demonstrate the ability and accuracy of this approach. The calculated
resonance parameters are compared with available results from other methods. It
is shown that in the presence of the Coulomb interaction, the spherical-box
approach works well for not so broad resonances. In particular, for very narrow
resonances, the present method gives resonance parameters in a very high
precision.Comment: 10 pages, 5 EPS figures; to be published in J. Phys.
The association between real-life markers of phone use and cognitive performance, health-related quality of life and sleep
INTRODUCTION: The real-life short-term implications of electromagnetic fields (RF-EMF) on cognitive performance and health-related quality of life have not been well studied. The SPUTNIC study (Study Panel on Upcoming Technologies to study Non-Ionizing radiation and Cognition) aimed to investigate possible correlations between mobile phone radiation and human health, including cognition, health-related quality of life and sleep. METHODS: Adult participants tracked various daily markers of RF-EMF exposures (cordless calls, mobile calls, and mobile screen time 4 h prior to each assessment) as well as three health outcomes over ten study days: 1) cognitive performance, 2) health-related quality of life (HRQoL), and 3) sleep duration and quality. Cognitive performance was measured through six "game-like" tests, assessing verbal and visuo-spatial performance repeatedly. HRQoL was assessed as fatigue, mood and stress on a Likert-scale (1-10). Sleep duration and efficiency was measured using activity trackers. We fitted mixed models with random intercepts per participant on cognitive, HRQoL and sleep scores. Possible time-varying confounders were assessed at daily intervals by questionnaire and used for model adjustment. RESULTS: A total of 121 participants ultimately took part in the SPUTNIC study, including 63 from Besancon and 58 from Basel. Self-reported wireless phone use and screen time were sporadically associated with visuo-spatial and verbal cognitive performance, compatible with chance findings. We found a small but robust significant increase in stress 0.03 (0.00-0.06; on a 1-10 Likert-scale) in relation to a 10-min increase in mobile phone screen time. Sleep duration and quality were not associated with either cordless or mobile phone calls, or with screen time. DISCUSSION: The study did not find associations between short-term RF-EMF markers and cognitive performance, HRQoL, or sleep duration and quality. The most consistent finding was increased stress in relation to more screen time, but no association with cordless or mobile phone call time
From spin liquid to magnetic ordering in the anisotropic kagome Y-Kapellasite Y3Cu9(OH)19Cl8: a single crystal study
Y3Cu9(OH)19Cl8 realizes an original anisotropic kagome model hosting a rich
magnetic phase diagram [M. Hering et al, npj Computational Materials 8, 1
(2022)]. We present an improved synthesis of large phase-pure single crystals
via an external gradient method. These crystals were investigated in details by
susceptibility, specific heat, thermal expansion, neutron scattering and local
muSR and NMR techniques. At variance with polycristalline samples, the study of
single crystals gives evidence for subtle structural instabilities at 33K and
13K which preserve the global symmetry of the system and thus the magnetic
model. At 2.1K the compound shows a magnetic transition to a coplanar (1/3,1/3)
long range order as predicted theoretically. However our analysis of the spin
wave excitations yields magnetic interactions which locate the compound closer
to the phase boundary to a classical jammed spin liquid phase. Enhanced quantum
fluctuations at this boundary may be responsible for the strongly reduced
ordered moment of the Cu2+, estimated to be 0.075muB from muSR
The dynamical Green's function and an exact optical potential for electron-molecule scattering including nuclear dynamics
We derive a rigorous optical potential for electron-molecule scattering
including the effects of nuclear dynamics by extending the common many-body
Green's function approach to optical potentials beyond the fixed-nuclei limit
for molecular targets. Our formalism treats the projectile electron and the
nuclear motion of the target molecule on the same footing whereby the dynamical
optical potential rigorously accounts for the complex many-body nature of the
scattering target. One central result of the present work is that the common
fixed-nuclei optical potential is a valid adiabatic approximation to the
dynamical optical potential even when projectile and nuclear motion are
(nonadiabatically) coupled as long as the scattering energy is well below the
electronic excitation thresholds of the target. For extremely low projectile
velocities, however, when the cross sections are most sensitive to the
scattering potential, we expect the influences of the nuclear dynamics on the
optical potential to become relevant. For these cases, a systematic way to
improve the adiabatic approximation to the dynamical optical potential is
presented that yields non-local operators with respect to the nuclear
coordinates.Comment: 22 pages, no figures, accepted for publ., Phys. Rev.
The accuracy of frozen section analysis in ultrasound- guided core needle biopsy of breast lesions
<p>Abstract</p> <p>Background</p> <p>Limited data are available to evaluate the accuracy of frozen section analysis and ultrasound- guided core needle biopsy of the breast.</p> <p>Methods</p> <p>In a retrospective analysis data of 120 consecutive handheldultrasound- guided 14- gauge automated core needle biopsies (CNB) in 109 consecutive patients with breast lesions between 2006 and 2007 were evaluated.</p> <p>Results</p> <p>In our outpatient clinic120 CNB were performed. In 59/120 (49.2%) cases we compared histological diagnosis on frozen sections with those on paraffin sections of CNB and finally with the result of open biopsy. Of the cases 42/59 (71.2%) were proved to be malignant and 17/59 (28.8%) to be benign in the definitive histology. 2/59 (3.3%) biopsies had a false negative frozen section result. No false positive results of the intraoperative frozen section analysis were obtained, resulting in a sensitivity, specificity and positive predicting value (PPV) and negative predicting value (NPV) of 95%, 100%, 100% and 90%, respectively. Histological and morphobiological parameters did not show up relevance for correct frozen section analysis. In cases of malignancy time between diagnosis and definitive treatment could not be reduced due to frozen section analysis.</p> <p>Conclusion</p> <p>The frozen section analysis of suspect breast lesions performed by CNB displays good sensitivity/specificity characteristics. Immediate investigations of CNB is an accurate diagnostic tool and an important step in reducing psychological strain by minimizing the period of uncertainty in patients with breast tumor.</p
Polycyclic aromatic chains on metals and insulating layers by repetitive [3+2] cycloadditions
The vast potential of organic materials for electronic, optoelectronic and spintronic devices entails substantial interest in the fabrication of π-conjugated systems with tailored functionality directly at insulating interfaces. On-surface fabrication of such materials on non-metal surfaces remains to be demonstrated with high yield and selectivity. Here we present the synthesis of polyaromatic chains on metallic substrates, insulating layers, and in the solid state. Scanning probe microscopy shows the formation of azaullazine repeating units on Au(111), Ag(111), and h-BN/Cu(111), stemming from intermolecular homo-coupling via cycloaddition reactions of CN-substituted polycyclic aromatic azomethine ylide (PAMY) intermediates followed by subsequent dehydrogenation. Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry demonstrates that the reaction also takes place in the solid state in the absence of any catalyst. Such intermolecular cycloaddition reactions are promising methods for direct synthesis of regioregular polyaromatic polymers on arbitrary insulating surfaces.This work was financially supported by the European Research Council Consolidator Grant NanoSurfs (no. 615233), the Advanced Grant (no. 694097), the Horizon 2020 research and innovation program 2D ink (no. 664878) and the National Science Foundation of China (no. 11974403 and Sino-German Project no. 51761135130). W.A. acknowledges funding by the DFG via a Heisenberg professorship. M.R., R.B., and X.F. thank the German Research Foundation (DFG) within the Cluster of Excellence “Center for Advancing Electronics Dresden (cfaed)” and EnhanceNano (No. 391979941). A.P.P. and A.Ru. thank the Cluster of Excellence "Advanced Imaging of Matter (AIM)" and Grupos Consolidados (IT1249-19). M.G. acknowledges funding by the H2020-MSCA-IF−2014 program under GA no. 658070 (2DNano).Peer reviewe
Obstructed defaecation syndrome: European consensus guidelines on the surgical management.
Not availabl
Gating a single-molecule transistor with individual atoms
Transistors, regardless of their size, rely on electrical gates to control the
conductance between source and drain contacts. In atomic-scale transistors,
this conductance is sensitive to single electrons hopping via individual
orbitals1, 2. Single-electron transport in molecular transistors has been
previously studied using top-down approaches to gating, such as lithography
and break junctions1, 3, 4, 5, 6, 7, 8, 9, 10, 11. But atomically precise
control of the gate—which is crucial to transistor action at the smallest size
scales—is not possible with these approaches. Here, we used individual charged
atoms, manipulated by a scanning tunnelling microscope12, to create the
electrical gates for a single-molecule transistor. This degree of control
allowed us to tune the molecule into the regime of sequential single-electron
tunnelling, albeit with a conductance gap more than one order of magnitude
larger than observed previously8, 11, 13, 14. This unexpected behaviour arises
from the existence of two different orientational conformations of the
molecule, depending on its charge state. Our results show that strong coupling
between these charge and conformational degrees of freedom leads to new
behaviour beyond the established picture of single-electron transport in
atomic-scale transistors
- …