2,238 research outputs found
First-principles analysis of spin-disorder resistivity of Fe and Ni
Spin-disorder resistivity of Fe and Ni and its temperature dependence are
analyzed using noncollinear density functional calculations within the
supercell method. Different models of thermal spin disorder are considered,
including the mean-field approximation and the nearest-neighbor Heisenberg
model. Spin-disorder resistivity is found to depend weakly on magnetic
short-range order. If the local moments are kept frozen at their
zero-temperature values, very good agreement with experiment is obtained for
Fe, but for Ni the resistivity at elevated temperatures is significantly
overestimated. Agreement with experiment for Fe is improved if the local
moments are iterated to self-consistency. The overestimation of the resistivity
for paramagnetic Ni is attributed to the reduction of the local moments down to
0.35 Bohr magnetons. Overall, the results suggest that low-energy spin
fluctuations in Fe and Ni are better viewed as classical rotations of local
moments rather than quantized spin fluctuations that would require an (S+1)/S
correction.Comment: 10 pages (RevTeX), 6 eps figure
Explaining LIGO's observations via isolated binary evolution with natal kicks
We compare binary evolution models with different assumptions about
black-hole natal kicks to the first gravitational-wave observations performed
by the LIGO detectors. Our comparisons attempt to reconcile merger rate,
masses, spins, and spin-orbit misalignments of all current observations with
state-of-the-art formation scenarios of binary black holes formed in isolation.
We estimate that black holes (BHs) should receive natal kicks at birth of the
order of (50) km/s if tidal processes do (not) realign
stellar spins. Our estimate is driven by two simple factors. The natal kick
dispersion is bounded from above because large kicks disrupt too many
binaries (reducing the merger rate below the observed value). Conversely, the
natal kick distribution is bounded from below because modest kicks are needed
to produce a range of spin-orbit misalignments. A distribution of misalignments
increases our models' compatibility with LIGO's observations, if all BHs are
likely to have natal spins. Unlike related work which adopts a concrete BH
natal spin prescription, we explore a range of possible BH natal spin
distributions. Within the context of our models, for all of the choices of
used here and within the context of one simple fiducial parameterized
spin distribution, observations favor low BH natal spin.Comment: 19 pages, 14 figures, as published in PR
Calculations of spin-disorder resistivity from first principles
Spin-disorder resistivity of Fe and Ni is studied using the noncollinear
density functional theory. The Landauer conductance is averaged over random
disorder configurations and fitted to Ohm's law. The distribution function is
approximated by the mean-field theory. The dependence of spin-disorder
resistivity on magnetization in Fe is found to be in excellent agreement with
the results for the isotropic s-d model. In the fully disordered state,
spin-disorder resistivity for Fe is close to experiment, while for fcc Ni it
exceeds the experimental value by a factor of 2.3. This result indicates strong
magnetic short-range order in Ni at the Curie temperature.Comment: 3 pages, 3 figure
PHENIX first measurement of the J/psi elliptic flow parameter v2 in Au+Au collisions at sqrt(sNN) = 200 GeV
Recent results indicate that the J/psi suppression pattern differs with
rapidity showing a larger suppression at forward rapidity. J/psi suppression
mechanisms based on energy density (such as color screening, interaction with
co-movers, etc.) predict the opposite trend. On the other hand, it is expected
that more c\bar{c} pairs should be available to form quarkonia at mid-rapidity
via recombination. Some models provide a way to differentiate J/psi production
from initially produced c\bar{c} pairs and final state recombination of
uncorrelated pairs, via the rapidity and transverse momentum dependence of the
elliptic flow (v2).
During 2007 data taking at RHIC, a large sample of Au+Au collisions at
sqrt(sNN)=200 GeV was collected. The statistics has been increased compared to
previous 2004 data set, thus allowing a more precise measurement of the J/psi
production at both mid and forward rapidity. Furthermore, the PHENIX experiment
benefited from the addition of a new detector, which improves the reaction
plane resolution and allows us to measure the J/psi v2. Comparing this
measurement to the positive D-mesons v2 (through non-photonic electron decays)
will help constraining the J/psi production mechanisms and getting a more
precise picture of the proportion of J/psi coming from direct production or
charm quark coalescence.
Details on how the J/psi v2 is measured at both rapidities are presented. The
J/psi v2 as a function of transverse momentum are compared to existing models.Comment: 4 pages, 3 figures, Quark Matter 2008 proceeding
The Impact of Olfactory Disorders in the United Kingdom
Olfactory disorders are believed to affect 5% of the general population and have been shown to bear significant psychosocial consequences to sufferers. Although more common than blindness and profound deafness in the United Kingdom, the impact of these disorders has not been assessed to date and the plight of British patients has yet to be quantified. In 2012, a patient support organization, Fifth Sense, was founded to provide information and support to sufferers of chemosensory disorders. Following a recent members conference, a survey of the membership was conducted anonymously using a series of questions based on an existing olfactory disorders questionnaire. From 496 respondents, this has demonstrated high rates of depression (43%) and anxiety (45%), impairment of eating experience (92%), isolation (57%), and relationship difficulties (54%). Women appear to have significantly more issues than men in terms of social and domestic dysfunction relating to olfactory loss (P = 0.01). Qualitative disorders also affected more than 1 in 5 members with parosmia reported in 19% and phantosmia in 24%. This paper discusses the details of the British story of anosmia and other related disorders as depicted by those most affected
Action des sulfonates d'éthyle et de méthyle méthane sur l'injection d'ADN et la recombinaison génétique dans le bactériophage T7.
peer reviewedAfter treatment with methyl or ethyl methane sulfonate, T7 amber mutants display a reduced capacity for recombination. Moreover, alkylation reduces recombination frequency involving markers on the right-hand side of the genetic map more than it reduces recombination frequency involving markers on the left-hand side. We interpret this to mean that alkylation can stop DNA injection at any point along the DNA molecule, and that T7 phage injects its DNA in a unique fashion starting from the end carrying the genes for early proteins
Increasing integrated testing in community settings through interventions for change, including the Spring European Testing Week
Background: Maximising access to testing by targeting more than one infection is effective in identifying new infections in settings or populations. Within the EU funded Joint Action INTEGRATE, this paper examined the feasibility and impact of expanding integrated testing for HIV, hepatitis C (HCV), chlamydia, gonorrhoea and/or syphilis in four community-based pilots through targeted interventions in Croatia, Italy and Poland and the Spring European Testing Week since community settings are key in detecting new infections and reaching key populations.
Methods: Pilots led by local INTEGRATE partners prioritised testing for other infections or key populations. The Croatian pilot expanded testing for men who have sex with men to syphilis, chlamydia and gonorrhoea. Italian partners implemented a HIV and HCV testing/information event at a migrant centre. A second Italian pilot tested migrants for HIV and HCV through outreach and a low-threshold service for people who use drugs. Polish partners tested for HIV, HCV and syphilis among people who inject drugs in unstable housing via a mobile van. Pilots monitored the number of individuals tested for each infection and reactive results.
The pilot Spring European Testing Week from 18 to 25 May 2018 was an INTEGRATE-driven initiative to create more testing awareness and opportunities throughout Europe.
Results: The Croatian pilot found a high prevalence for each syphilis, chlamydia and gonorrhoea respectively, 2.1%, 12.4% and 6.7%. The Italian migrant centre pilot found low proportions who were previously tested for HIV (24%) or HCV (11%) and the second Italian pilot found an HCV prevalence of 6.2%, with low proportions previously tested for HIV (33%) or HCV (31%). The Polish pilot found rates of being previously tested for HIV, HCV and syphilis at 39%, 37%, and 38%, respectively. Results from the Spring European Testing Week pilot showed it was acceptable with increased integrated testing, from 50% in 2018 to 71% in 2019 in participants.
Conclusions: Results show that integrated testing is feasible and effective in community settings, in reaching key populations and minimising missed testing opportunities, and the pilots made feasible because of the European collaboration and funding. For sustainability and expansion of integrated community testing across Europe, local government investment in legislation, financial and structural support are crucial.The INTEGRATE Joint Action was co-funded by the 3rd Health Programme of the European Union under grant agreement no 761319. The EuroTEST/European Testing Week initiative has received funding and grants from Gilead Sciences, ViiV Healthcare, Janssen, Merck/MSD and the European Commission under the 3rd and 2nd Health Programmes. HUHIV: CheckPoint Zagreb is funded by cooperation programs by the City of Zagreb and Ministry of Health incl. HIV, HCV and syphilis rapid tests, CT/NG tests are donated by Cepheid with the contribution of the Department of Immunological and Molecular Diagnostics of the Clinic for Infectious Diseases Dr Fran Mihaljević during the pilot project. CRI/FVM: For the pilot activity in the migrant centre, HIV and HCV rapid tests were donated by FVM/CRI. Moreover, FVM contributed with the staff and equipment (mobile unit). FVM: The medical centre and outreach street unit are funded by the Health Department of Lazio Regional Administration of Italy. NAC/FES: Funding for FES pilot in 2019 was provided by NAC. FES secured their staff, mobile unit and tests. Daniel Simões is the recipient of PhD Grant PD/BD/128008/2016 from Fundação para a Ciência e Tecnologia (FCT). All funders had no role in the study design, analysis, decision to publish, or preparation of the manuscript
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