1,624 research outputs found
Temperature-dependent proximity magnetism in Pt
We experimentally demonstrate the existence of magnetic coupling between two
ferromagnets separated by a thin Pt layer. The coupling remains ferromagnetic
regardless of the Pt thickness, and exhibits a significant dependence on
temperature. Therefore, it cannot be explained by the established mechanisms of
magnetic coupling across nonmagnetic spacers. We show that the experimental
results are consistent with the presence of magnetism induced in Pt in
proximity to ferromagnets, in direct analogy to the well-known proximity
effects in superconductivity.Comment: 4 pages, 3 figure
Civil society and financial markets : what is not happening and why
Why have commercial financial flows â as a major force in contemporary society with a number of significant problematic consequences â attracted relatively little effective public-interest response from civil society? Change-oriented NGOs, labour unions, faith-based organisations and other social movements have mostly remained in the shadows vis-Ă -vis private financial markets. Impacts from these citizen associations have not gone beyond promoting modest rises in public awareness, certain limited policy shifts, and minor institutional reforms of a few public governance agencies. The reasons for these scant achievements are partly related to capacities and practices in civil society groups, relevant governance agencies, and financial firms. Also important in constraining civil society impacts to reform and transform contemporary financial markets are deeper structural circumstances such as embedded social hierarchies (among countries, classes, etc.), the pivotal role of finance capital in accumulation processes today, and the entrenchment of prevailing neoliberal policy discourses
You can't see what you can't see: Experimental evidence for how much relevant information may be missed due to Google's Web search personalisation
The influence of Web search personalisation on professional knowledge work is
an understudied area. Here we investigate how public sector officials
self-assess their dependency on the Google Web search engine, whether they are
aware of the potential impact of algorithmic biases on their ability to
retrieve all relevant information, and how much relevant information may
actually be missed due to Web search personalisation. We find that the majority
of participants in our experimental study are neither aware that there is a
potential problem nor do they have a strategy to mitigate the risk of missing
relevant information when performing online searches. Most significantly, we
provide empirical evidence that up to 20% of relevant information may be missed
due to Web search personalisation. This work has significant implications for
Web research by public sector professionals, who should be provided with
training about the potential algorithmic biases that may affect their judgments
and decision making, as well as clear guidelines how to minimise the risk of
missing relevant information.Comment: paper submitted to the 11th Intl. Conf. on Social Informatics;
revision corrects error in interpretation of parameter Psi/p in RBO resulting
from discrepancy between the documentation of the implementation in R
(https://rdrr.io/bioc/gespeR/man/rbo.html) and the original definition
(https://dl.acm.org/citation.cfm?id=1852106) as per 20/05/201
Socioeconomic position and hysterectomy: a cross-cohort comparison of women in Australia and Great Britain
Objectives: To examine the associations between indicators of socioeconomic position (SEP) and hysterectomy in two Australian and two British cohorts
High-power femtosecond mid-infrared optical parametric oscillator at 7ââÎŒm based on CdSiP2
We report a femtosecond optical parametric oscillator (OPO) for the mid-infrared (mid-IR), generating a record average power of 110 mW at 7 ÎŒm. The OPO, based on CdSiP2 (CSP) as the nonlinear crystal, provides idler wavelength tuning across 6540â7186 nm with spectral bandwidths >400âânm at â10ââdB level over the entire range, and a maximum bandwidth of 478 nm at 6.9 ÎŒm. To the best of our knowledge, this is the highest average power generated from a femtosecond OPO in the deep mid-IR. The OPO also provides near-IR signal wavelengths tunable across 1204â1212 nm with a usable power of 450 mW in 418-fs pulses at 1207 nm. The simultaneously measured signal and idler power exhibit a passive stability better than 1.6% rms and 3% rms, respectively. A mid-IR idler spectral stability with a standard deviation of the frequency fluctuations better than 40 MHz over 15 min, limited by the measurement resolution, is realized. Using the mid-IR idler from the CSP OPO, we perform Fourier-transform spectroscopy to detect liquid phase organic solvent, toluene (C7H8), in the molecular fingerprint region.Postprint (authorâs final draft
Semi-classical Probe Strings on Giant Gravitons Backgrounds
In the first part of this paper we study two symmetries of the LLM
metric, both of which exchange black and white regions. One of them which can
be interpreted as the particle-hole symmetry is the symmetry of the whole
supergravity solution while the second one is just the symmetry of the metric
and changes the sign of the fivefrom flux. In the second part of the paper we
use closed string probes and their semi-classical analysis to compare the two
1/2 BPS deformations of , the smooth LLM geometry which
contains localized giant gravitons and the superstar case which is a solution
with naked singularity corresponding to smeared giants. We discuss the
realization of the symmetry in the semi-classical closed string probes
point of view.Comment: 29 pages, 6 .eps figures; v2: References adde
Cotinine-assessed second-hand smoke exposure and risk of cardiovascular disease in older adults
Objectives: To examine whether second-hand smoke (SHS) exposure measured by serum cotinine is associated with increased coronary heart disease (CHD) and stroke risk among contemporary older British adults.
Design: Prospective population-based study with self-reported medical history and health behaviours. Fasting blood samples were analysed for serum cotinine and cardiovascular disease (CVD) risk markers.
Setting: Primary care centres in 25 British towns in 1998â2001.
Patients: 8512 60â79-year-old men and women selected from primary care registers.
Main outcome measures: Fatal and non-fatal myocardial infarction (MI; n=445) and stroke (n=386) during median 7.8-year follow-up.
Main exposure: Observational study of serum cotinine assayed from fasting blood sample using liquid chromatography tandem mass spectrometry method, and self-reported smoking history.
Results: Among 5374 non-smokers without pre-existing CVD, geometric mean cotinine was 0.15â
ng/ml (IQR 0.05â0.30). Compared with non-smokers with cotinine â€0.05â
ng/ml, higher cotinine levels (0.06â0.19, 0.2â0.7 and 0.71â15.0â
ng/ml) showed little association with MI; adjusted HRs were 0.92 (95% CI 0.63 to 1.35), 1.07 (0.73 to 1.55) and 1.09 (0.69 to 1.72), p(trend)=0.69. Equivalent HRs for stroke were 0.82 (0.55 to 1.23), 0.74 (0.48 to 1.13) and 0.69 (0.41 to 1.17), p(trend)=0.065. The adjustment for sociodemographic, behavioural and CVD risk factors had little effect on the results. The HR of MI for smokers (1â9 cigarettes/day) compared with non-smokers with cotinine â€0.05â
ng/ml was 2.14 (1.39 to 3.52) and 1.03 (0.52 to 2.04) for stroke.
Conclusions: In contemporary older men and women, SHS exposure (predominantly at low levels) was not related to CHD or stroke risks, but we cannot rule out the possibility of modest effects at higher exposure levels
Fermions from Half-BPS Supergravity
We discuss collective coordinate quantization of the half-BPS geometries of
Lin, Lunin and Maldacena (hep-th/0409174). The LLM geometries are parameterized
by a single function on a plane. We treat this function as a collective
coordinate. We arrive at the collective coordinate action as well as path
integral measure by considering D3 branes in an arbitrary LLM geometry. The
resulting functional integral is shown, using known methods (hep-th/9309028),
to be the classical limit of a functional integral for free fermions in a
harmonic oscillator. The function gets identified with the classical limit
of the Wigner phase space distribution of the fermion theory which satisfies u
* u = u. The calculation shows how configuration space of supergravity becomes
a phase space (hence noncommutative) in the half-BPS sector. Our method sheds
new light on counting supersymmetric configurations in supergravity.Comment: 28 pages, 2 figures, epsf;(v3) eq. (3.3) clarified and notationally
simplified; version to appear in JHE
Vehicular traffic flow at an intersection with the possibility of turning
We have developed a Nagel-Schreckenberg cellular automata model for
describing of vehicular traffic flow at a single intersection. A set of traffic
lights operating in fixed-time scheme controls the traffic flow. Open boundary
condition is applied to the streets each of which conduct a uni-directional
flow. Streets are single-lane and cars can turn upon reaching to the
intersection with prescribed probabilities. Extensive Monte Carlo simulations
are carried out to find the model flow characteristics. In particular, we
investigate the flows dependence on the signalisation parameters, turning
probabilities and input rates. It is shown that for each set of parameters,
there exist a plateau region inside which the total outflow from the
intersection remains almost constant. We also compute total waiting time of
vehicles per cycle behind red lights for various control parameters.Comment: 8 pages, 17 eps figures, Late
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