1,713 research outputs found
Fredkin Gates for Finite-valued Reversible and Conservative Logics
The basic principles and results of Conservative Logic introduced by Fredkin
and Toffoli on the basis of a seminal paper of Landauer are extended to
d-valued logics, with a special attention to three-valued logics. Different
approaches to d-valued logics are examined in order to determine some possible
universal sets of logic primitives. In particular, we consider the typical
connectives of Lukasiewicz and Godel logics, as well as Chang's MV-algebras. As
a result, some possible three-valued and d-valued universal gates are described
which realize a functionally complete set of fundamental connectives.Comment: 57 pages, 10 figures, 16 tables, 2 diagram
The Lorentz transformations of the vectors E, B, P, M and the external electric fields from a stationary superconducting wire with a steady current and from a stationary permanent magnet
In the first part of this paper we review the fundamental difference between
the usual transformations of the three-dimensional (3D) vectors of the electric
field , the magnetic field , the polarization
, the magnetization and the Lorentz transformations of
the 4D geometric quantities, vectors E, B, P, M, with many additional
explanations and several new results. In the second part, we have discussed the
existence of the electric field vector E outside a stationary superconducting
wire with a steady current and also different experiments for the detection of
such electric fields. Furthermore, a fundamental prediction of the existence of
the external electric field vector E from a stationary permanent magnet is
considered. These electric fields are used for the resolution of the
"charge-magnet paradox" with 4D geometric quantities for a qualitative
explanation of the Aharonov-Bohm effect in terms of fields and not, as usual,
in terms of the vector potential and for a qualitative explanation that the
particle interference is not a test of a Lorentz-violating model of
electrodynamics according to which a magnetic solenoid generates not only a
static magnetic field but also a static electric field.Comment: 57 pages, minor changes, this version will be published in the
Proceedings of the IARD 201
Boolean Dynamics with Random Couplings
This paper reviews a class of generic dissipative dynamical systems called
N-K models. In these models, the dynamics of N elements, defined as Boolean
variables, develop step by step, clocked by a discrete time variable. Each of
the N Boolean elements at a given time is given a value which depends upon K
elements in the previous time step.
We review the work of many authors on the behavior of the models, looking
particularly at the structure and lengths of their cycles, the sizes of their
basins of attraction, and the flow of information through the systems. In the
limit of infinite N, there is a phase transition between a chaotic and an
ordered phase, with a critical phase in between.
We argue that the behavior of this system depends significantly on the
topology of the network connections. If the elements are placed upon a lattice
with dimension d, the system shows correlations related to the standard
percolation or directed percolation phase transition on such a lattice. On the
other hand, a very different behavior is seen in the Kauffman net in which all
spins are equally likely to be coupled to a given spin. In this situation,
coupling loops are mostly suppressed, and the behavior of the system is much
more like that of a mean field theory.
We also describe possible applications of the models to, for example, genetic
networks, cell differentiation, evolution, democracy in social systems and
neural networks.Comment: 69 pages, 16 figures, Submitted to Springer Applied Mathematical
Sciences Serie
Patient understanding of genetic information influences reproductive decision making in retinoblastoma
Retinoblastoma is the most common malignant tumour of the eye in childhood, with nearly all bilateral tumours and around 17-18% of unilateral tumours due to an oncogenic mutation in the RB1 gene in the germline. Genetic testing in all cases enables accurate risk assessment and optimal clinical management for the affected individual, siblings, and future offspring. We carried out the first UK-wide audit of understanding of genetic testing in individuals with retinoblastoma. A total of 292 individuals aged 16-45 years were included. Patients with bilateral disease were significantly more likely to understand the implications of retinoblastoma for siblings and children. There was a significant association between not knowing the results of genetic testing or not understanding the implications and not having children, particularly in women. Surprisingly, this was also true for individuals treated for unilateral disease with a low risk of retinoblastoma for their offspring. We are concerned that individuals may be making life choices based on insufficient information regarding risks of retinoblastoma and reproductive options. We suggest that improvement in transition care is needed to enable individuals to make informed reproductive decisions and to ensure optimal care for children born at risk of retinoblastoma
Designing stem-cell-based dopamine cell replacement trials for Parkinson's disease
Clinical studies of Parkinson’s disease (PD) using a dopamine cell replacment strategy have been tried for more than 30 years. The outcomes following transplantation of human fetal ventral mesencephalic tissue (hfVM) have been variable, with some patients coming off their anti-PD treatment for many years and others not responding and/or developing significant side effects, including graft-induced dyskinesia. This led to a re-appraisal of the best way to do such trials, which resulted in a new European-Union-funded allograft trial with fetal dopamine cells across several centers in Europe. This new trial, TRANSEURO (NCT01898390), is an open-label study in which some individuals in a large observational cohort of patients with mild PD who were undergoing identical assessments were randomly selected to receive transplants of hfVM. The TRANSEURO trial is currently ongoing as researchers have completed both recruitment into a large multicenter observational study of younger onset early-stage PD and transplantation of hfVM in 11 patients. While completion of TRANSEURO is not expected until 2021, we feel that sharing the rationale for the design of TRANSEURO, along with the lessons we have learned along the way, can help inform researchers and facilitate planning of transplants of dopamine-producing cells derived from human pluripotent stem cells for future clinical trials
Is short-term-variation of fetal-heart-rate a better predictor of fetal acidaemia in labour? A feasibility study
Background
Continuous intrapartum fetal monitoring is challenging and its clinical benefits are debated. The project evaluated whether short-term-variation (STV) and other computerised fetal heart rate (FHR) parameters (baseline FHR, long-term-variation, accelerations and decelerations) predicted acidaemia at birth. The aims of the study were to assess the changes in FHR pattern during labour and determine the feasibility of undertaking a definitive trial by reporting the practicalities of using the monitoring device, participant recruitment, data collection and staff training.
Methods
200 high-risk women carrying a term singleton, non-anomalous fetus, requiring continuous FHR monitoring in labour were consented to participate from the Jessop Wing maternity unit, Sheffield, UK. The trans-abdominal fetal ECG monitor was placed as per clinical protocol. During the monitoring session, clinicians were blinded to the computerised FHR parameters. We analysed the last hour of the FHR and its ability to predict umbilical arterial blood pH <7.20 using receiver operator characteristics (ROC) curves.
Results
Of 200 women, 137 cases were excluded as either the monitor did not work from the onset of labour (n = 30), clinical staff did not return or used the monitor on another patient (n = 37), umbilical cord blood not obtained (n = 25), FHR data not recorded within an hour of birth (n = 34) and other reasons (n = 11). In 63 cases included in the final analysis, the computer-derived FHR parameters did not show significant correlation with umbilical artery cord pH <7.20. Labour was associated with a significant increase in short and long term variation of FHR and number of deceleration (P<0.001). However, baseline FHR decreased significantly before delivery (P<0.001).
Conclusions
The project encountered a number of challenges, with learning points crucial to informing the design of a large study to evaluate the potential place of intrapartum computerised FHR parameters, using abdominal fetal ECG monitor before its clinical utility and more widespread adoption can be ascertained
Measurement of the cross-section and charge asymmetry of bosons produced in proton-proton collisions at TeV with the ATLAS detector
This paper presents measurements of the and cross-sections and the associated charge asymmetry as a
function of the absolute pseudorapidity of the decay muon. The data were
collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with
the ATLAS experiment at the LHC and correspond to a total integrated luminosity
of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements
varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the
1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured
with an uncertainty between 0.002 and 0.003. The results are compared with
predictions based on next-to-next-to-leading-order calculations with various
parton distribution functions and have the sensitivity to discriminate between
them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables,
submitted to EPJC. All figures including auxiliary figures are available at
https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13
Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector
A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13 TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV
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