1,665 research outputs found
N-qubit states as points on the Bloch sphere
We show how the Majorana representation can be used to express the pure
states of an N-qubit system as points on the Bloch sphere. We compare this
geometrical representation of N-qubit states with an alternative one, proposed
recently by the present authors.Comment: 9 pages, 2 figures, contribution to CEWQO 2009 proceedings. v2: Minor
changes, published versio
Testing the Empirical Shock Arrival Model using Quadrature Observations
The empirical shock arrival (ESA) model was developed based on quadrature
data from Helios (in-situ) and P-78 (remote-sensing) to predict the Sun-Earth
travel time of coronal mass ejections (CMEs) [Gopalswamy et al. 2005a]. The ESA
model requires earthward CME speed as input, which is not directly measurable
from coronagraphs along the Sun-Earth line. The Solar Terrestrial Relations
Observatory (STEREO) and the Solar and Heliospheric Observatory (SOHO) were in
quadrature during 2010 - 2012, so the speeds of Earth-directed CMEs were
observed with minimal projection effects. We identified a set of 20 full halo
CMEs in the field of view of SOHO that were also observed in quadrature by
STEREO. We used the earthward speed from STEREO measurements as input to the
ESA model and compared the resulting travel times with the observed ones from
L1 monitors. We find that the model predicts the CME travel time within about
7.3 hours, which is similar to the predictions by the ENLIL model. We also find
that CME-CME and CME-coronal hole interaction can lead to large deviations from
model predictions.Comment: 17 pages, 4 figures, 3 table
Dengue in Finnish international travelers, 2016–2019:a retrospective analysis of places of exposure and the factors associated with the infection
Abstract. As an emerging infectious disease dengue is putting a constantly growing number of international tourists at risk of the infection. To have a more complete picture of the phenomena among the Finnish travelers, the backgrounds of infections were retrospectively examined to find out the place of exposure, type of traveler and the trip, risk perceptions and protective measures taken. The study period was from January 2016 to May 2019 and reported dengue infections from this period were obtained from the National Infectious Disease Register, which is maintained by the Finnish Institute for Health and Welfare (THL). The questionnaire both in Finnish and Swedish was sent to the participants. The response rate in this study was 61.3 %.
Data was analyzed spatially with QGIS 3.4.8 Madeira and statistically by using R 3.6.0. Descriptive statistics were used to analyze the demographic variables as well as answers given to the questionnaire. In addition, two binary logistic models were fitted to find out statistically significant factors for risk perception and the use of protective measures. Crude attack rates were calculated for different destinations using UNWTO travel data. Further on, the results were compared to existing literature related to this research.
Thailand and Indonesia were identified as destinations with the most abundant number of infections imported to Finland. However, Maldives had the highest crude attack rate per 100,000 travelers. The type of travel during which the infections were acquired was mainly pre-booked holiday of 14 days with time spent mostly on the beach. Most of the travelers were not aware of the dengue risk before the travel and did not seek pre-travel advice. Those who sought pre-travel advice were 34.9 times more likely to use protective measures than those who did not. Moreover, the majority applied some protective measures but not during the right time of the day, and thus the measures were chosen incorrectly.
Based on these results the knowledge about dengue, day-active/urban mosquito and the correct use of protective measures needs increasing. Further on, the risk within touristic destinations requires highlighting and the distinction between malaria and other mosquito-borne diseases could be made clearer. In addition, there is a need to increase the knowledge of dengue among healthcare workers
Decay of an isolated monopole into a Dirac monopole configuration
We study numerically the detailed structure and decay dynamics of isolated
monopoles in conditions similar to those of their recent experimental
discovery. We find that the core of a monopole in the polar phase of a spin-1
Bose-Einstein condensate contains a small half-quantum vortex ring. Well after
the creation of the monopole, we observe a dynamical quantum phase transition
that destroys the polar phase. Strikingly, the resulting ferromagnetic order
parameter exhibits a Dirac monopole in its synthetic magnetic field.Comment: 6 pages, 5 figure
Inert states of spin-S systems
We present a simple but efficient geometrical method for determining the
inert states of spin-S systems. It can be used if the system is described by a
spin vector of a spin-S particle and its energy is invariant in spin rotations
and phase changes. Our method is applicable to an arbitrary S and it is based
on the representation of a pure spin state of a spin-S particle in terms of 2S
points on the surface of a sphere. We use this method to find candidates for
some of the ground states of spinor Bose-Einstein condensates.Comment: 4 pages, 2 figures, minor changes, references added, typos correcte
SEPARATION OF NORMAL AND IMMUNE LYMPHOID CELLS BY ANTIGEN-COATED COLUMNS : ANTIGEN-BINDING CHARACTERISTICS OF MEMBRANE ANTIBODIES AS ANALYZED BY HAPTEN-PROTEIN ANTIGENS
Specific fractionation of immunologically competent cells derived from normal or immune animals was achieved by filtration through antigen-coated bead columns. This selective retention of the relevant reactive cells could be shown to produce a cell population, which after passage through the column would behave like a suspension rendered immunologically tolerant by "classical" means. The immunologically specific elimination of potential antibody-forming capacity of the filtered cells could be shown to affect the IgM and the IgG system to a similar extent. Analysis of the binding characteristics of the membrane antibodies responsible for this selective retention indicate striking similarities to those of the humoral antibodies produced against the antigen. Thus, the surface receptor could distinguish isolated haptenic groups on a "foreign" carrier background and the receptor of the hapten-reactive cells in the present system (high-rate antibody-forming cells against NIP) failed to combine with carrier specific determinants in analogy with the binding behavior of the serum anti-hapten antibodies. The binding of anti-hapten reactive cells to bead-attached haptens could be specifically inhibited by the presence of free hapten in the columnar fluid during cellular filtration. The results strongly suggest that the potential humoral antibody-forming cell has preformed receptors on its outer surface with binding characteristics, indicating similarity, if not identity, to those of the eventual product of the cell, the humoral antibody
A Hierarchical Relationship between the Fluence Spectra and CME Kinematics in Large Solar Energetic Particle Events: A Radio Perspective
We report on further evidence that solar energetic particles are organized by
the kinematic properties of coronal mass ejections (CMEs)[1]. In particular, we
focus on the starting frequency of type II bursts, which is related to the
distance from the Sun where the radio emission starts. We find that the three
groups of solar energetic particle (SEP) events known to have distinct values
of CME initial acceleration, also have distinct average starting frequencies of
the associated type II bursts. SEP events with ground level enhancement (GLE)
have the highest starting frequency (107 MHz), while those associated with
filament eruption (FE) in quiescent regions have the lowest starting frequency
(22 MHz); regular SEP events have intermediate starting frequency (81 MHz).
Taking the onset time of type II bursts as the time of shock formation, we
determine the shock formation heights measured from the Sun center. We find
that the shocks form on average closest to the Sun (1.51 Rs) in GLE events,
farthest from the Sun in FE SEP events (5.38 Rs), and at intermediate distances
in regular SEP events (1.72 Rs). Finally, we present the results of a case
study of a CME with high initial acceleration (~3 km s^-2) and a type II radio
burst with high starting frequency (~200 MHz) but associated with a minor SEP
event. We find that the relation between the fluence spectral index and CME
initial acceleration continues to hold even for this minor SEP event.Comment: 11 pages, 7 figures, 1 table, to appear in Journal of Physics:
Conference Series (JPCS), Proceedings of the 16th Annual International
Astrophysics Conference held in Santa Fe, NM, 201
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