1,099 research outputs found
Enhancing Tc in field-doped Fullerenes by applying uniaxial stress
Capitalizing on the two-dimensional nature of superconductivity in
field-effect doped C60, we show that it should be possible to increase the
transition temperature Tc by applying uniaxial stress perpendicular to the gate
electrode. This method not only holds the promise of substantially enhancing Tc
(by about 30 K per GPa), but also provides a sensitive check of the current
understanding of superconductivity in the doped Fullerenes.Comment: 3 pages RevTe
Evaluation of the quality and impact of online learning through the SAFE EUROPE webinars
IntroductionThe SAFE EUROPE project, a European-funded project, addressed educational gaps of Therapeutic Radiographers/Radiation Therapists (TR/RTTs) by offering a series of free webinars. This study aimed to assess the quality of these webinars and their impact on professional practice.MethodsData collection involved two methods: an automated feedback form administered after each webinar, supplemented by a survey disseminated through social media. The collected data encompassed attendance statistics, participants’ professions and geographic locations, webinar quality assessment, the acquisition of new knowledge and skills, the application of this newfound knowledge in practice, and the likelihood of recommending these webinars. Descriptive statistics and thematic analysis were used to analyse the quantitative and qualitative data, respectively. Ethical approval for the study was obtained.Results11,286 individuals from 107 countries participated in 18 webinars. Despite 72.7% being radiographers, a diverse array of professionals attended the webinars, including medical physicists, oncologists, radiologists, and academics. Remarkably, 98.7% of respondents rated the webinar quality as either good or excellent. The average rating for the likelihood of recommending these webinars to colleagues was 8.96/10. A substantial proportion of respondents expressed agreement or strong agreement that the webinars enhanced their knowledge (85%) and skills (73%). Furthermore, 79% of participants indicated that the webinars motivated them to change practice, with 65% having already implemented these changes. The insights from open-ended questions corroborated these findings.ConclusionThe webinars effectively achieved the aim of the SAFE EUROPE project to enhance practice by increasing knowledge and skills. Participants overwhelmingly endorsed the quality of these webinars.Implications for practiceWebinars represent a cost-efficient training tool that reaches a global audience and various radiography/radiotherapy professions. The development of additional webinars is strongly recommended.<br/
First detections of 610 MHz radio emission from hot magnetic stars
We have carried out a study of radio emission from a small sample of magnetic
O- and B-type stars using the Giant Metrewave Radio Telescope, with the goal of
investigating their magnetospheres at low frequencies. These are the lowest
frequency radio measurements ever obtained of hot magnetic stars. The
observations were taken at random rotational phases in the 1390 and the 610 MHz
bands. Out of the 8 stars, we detect five B-type stars in both the 1390 and the
610 MHz bands. The O-type stars were observed only in the 1390 MHz band, and no
detections were obtained. We explain this result as a consequence of free-free
absorption by the free-flowing stellar wind exterior to the closed
magnetosphere. We also study the variability of individual stars. One star - HD
133880 - exhibits remarkably strong and rapid variability of its low frequency
flux density. We discuss the possibility of this emission being coherent
emission as reported for CU Vir by Trigilio et al. (2000).Comment: 9 pages, 4 figures, 4 tables, submitted to MNRA
Investigating the origin of cyclical wind variability in hot, massive stars - I. On the dipolar magnetic field hypothesis
OB stars exhibit various types of spectral variability associated with wind
structures, including the apparently ubiquitous discrete absorption components
(DACs). These are proposed to be caused by either magnetic fields or non-radial
pulsations (NRPs). In this paper, we evaluate the possible relation between
large-scale, dipolar magnetic fields and the DAC phenomenon by investigating
the magnetic properties of a sample of 13 OB stars exhibiting well-documented
DAC behaviour.
Using high-precision spectropolarimetric data acquired in part in the context
of the Magnetism in Massive Stars (MiMeS) project, we find no evidence for
surface dipolar magnetic fields in any of these stars. Using Bayesian
inference, we compute upper limits on the strengths of the fields and use these
limits to assess two potential mechanisms by which the field may influence wind
outflow: magnetic wind confinement and local photospheric brightness
enhancements. Within the limits we derive, both mechanisms fail to provide a
systematic process capable of producing DACs in all of the stars of our sample.
Therefore, this implies that dipolar fields are highly unlikely to be
responsible for these structures in all massive stars, meaning that some other
mechanism must come into play.Comment: 17 pages, 6 figures, accepted for publication in MNRA
Stable isotope records for the last 10 000 years from Okshola cave (Fauske, northern Norway) and regional comparisons
The sensitivity of terrestrial environments to past changes in heat transport is expected to be manifested in Holocene climate proxy records on millennial to seasonal timescales. Stalagmite formation in the Okshola cave near Fauske (northern Norway) began at about 10.4 ka, soon after the valley was deglaciated. Past monitoring of the cave and surface has revealed stable modern conditions with uniform drip rates, relative humidity and temperature. Stable isotope records from two stalagmites provide time-series spanning from c. 10 380 yr to AD 1997; a banded, multi-coloured stalagmite (Oks82) was formed between 10 380 yr and 5050 yr, whereas a pristine, white stalagmite (FM3) covers the period from ~7500 yr to the present. The stable oxygen isotope (&delta;<sup>18</sup>O<sub>c</sub>), stable carbon isotope (&delta;<sup>13</sup>C<sub>c</sub>), and growth rate records are interpreted as showing i) a negative correlation between cave/surface temperature and &delta;<sup>18</sup>O<sub>c</sub>, ii) a positive correlation between wetness and &delta;<sup>13</sup>C<sub>c</sub>, and iii) a positive correlation between temperature and growth rate. Following this, the data from Okshola show that the Holocene was characterised by high-variability climate in the early part, low-variability climate in the middle part, and high-variability climate and shifts between two distinct modes in the late part. <br><br> A total of nine Scandinavian stalagmite &delta;<sup>18</sup>O<sub>c</sub> records of comparable dating precision are now available for parts or most of the Holocene. None of them show a clear Holocene thermal optimum, suggesting that they are influenced by annual mean temperature (cave temperature) rather than seasonal temperature. For the last 1000 years, &delta;<sup>18</sup>O<sub>c</sub> values display a depletion-enrichment-depletion pattern commonly interpreted as reflecting the conventional view on climate development for the last millennium. Although the &delta;<sup>18</sup>O<sub>c</sub> records show similar patterns and amplitudes of change, the main challenges for utilising high-latitude stalagmites as palaeoclimate archives are i) the accuracy of the age models, ii) the ambiguity of the proxy signals, and iii) calibration with monitoring data
Comparison of CDMS [100] and [111] oriented germanium detectors
The Cryogenic Dark Matter Search (CDMS) utilizes large mass, 3" diameter
1" thick target masses as particle detectors. The target is
instrumented with both phonon and ionization sensors and comparison of energy
in each channel provides event-by-event classification of electron and nuclear
recoils. Fiducial volume is determined by the ability to obtain good phonon and
ionization signal at a particular location. Due to electronic band structure in
germanium, electron mass is described by an anisotropic tensor with heavy mass
aligned along the symmetry axis defined by the [111] Miller index (L valley),
resulting in large lateral component to the transport. The spatial distribution
of electrons varies significantly for detectors which have their longitudinal
axis orientations described by either the [100] or [111] Miller indices.
Electric fields with large fringing component at high detector radius also
affect the spatial distribution of electrons and holes. Both effects are
studied in a 3 dimensional Monte Carlo and the impact on fiducial volume is
discussed.Comment: Low Temperature Detector 14 conference proceedings to be published in
the Journal of Low Temperature Physic
Precision measurements of Linear Scattering Density using Muon Tomography
We demonstrate that muon tomography can be used to precisely measure the
properties of various materials. The materials which have been considered have
been extracted from an experimental blast furnace, including carbon (coke) and
iron oxides, for which measurements of the linear scattering density relative
to the mass density have been performed with an absolute precision of 10%. We
report the procedures that are used in order to obtain such precision, and a
discussion is presented to address the expected performance of the technique
when applied to heavier materials. The results we obtain do not depend on the
specific type of material considered and therefore they can be extended to any
application.Comment: 16 pages, 4 figure
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