2,669 research outputs found
Properties of planetary fluids at high pressure and temperature
In order to derive models of the interiors of Uranus, Neptune, Jupiter and Saturn, researchers studied equations of state and electrical conductivities of molecules at high dynamic pressures and temperatures. Results are given for shock temperature measurements of N2 and CH4. Temperature data allowed demonstration of shock induced cooling in the the transition region and the existence of crossing isotherms in P-V space
Dynamics of the magnetic and structural a -> e phase transition in Iron
We have studied the high-pressure iron bcc to hcp phase transition by
simultaneous X-ray Magnetic Circular Dichroism (XMCD) and X-ray Absorption
Spectroscopy (XAS) with an X-ray dispersive spectrometer. The combination of
the two techniques allows us to obtain simultaneously information on both the
structure and the magnetic state of Iron under pressure. The magnetic and
structural transitions simultaneously observed are sharp. Both are of first
order in agreement with theoretical prediction. The pressure domain of the
transition observed (2.4 0.2 GPa) is narrower than that usually cited in
the literature (8 GPa). Our data indicate that the magnetic transition slightly
precedes the structural one, suggesting that the origin of the instability of
the bcc phase in iron with increasing pressure is to be attributed to the
effect of pressure on magnetism as predicted by spin-polarized full potential
total energy calculations
Antibodies to Seasonal Coronaviruses Rarely Cross-React with SARS-CoV-2: Findings from an African Birth Cohort
Antibodies to seasonal human-coronaviruses (sHCoV) may cross-protect against SARS-CoV-2. We investigated antibody responses in biobanked serum obtained before the pandemic from infants with polymerase chain reaction-confirmed sHCoV. Among 141 samples with antibodies to sHCoV, 4 (2.8%) were positive for SARS-CoV-2-S1 and 8 (5.7%) for SARS-CoV-2-S2. Antibodies to sHCoV rarely cross-react with SARS-CoV-2 antigens and are unlikely to account for mild pediatric illness
Optical absorption in the strong coupling limit of Eliashberg theory
We calculate the optical conductivity of superconductors in the
strong-coupling limit. In this anomalous limit the typical energy scale is set
by the coupling energy, and other energy scales such as the energy of the
bosons mediating the attraction are negligibly small. We find a universal
frequency dependence of the optical absorption which is dominated by bound
states and differs significantly from the weak coupling results. A comparison
with absorption spectra of superconductors with enhanced electron-phonon
coupling shows that typical features of the strong-coupling limit are already
present at intermediate coupling.Comment: 10 pages, revtex, 4 uuencoded figure
Self-organization in systems of self-propelled particles
We investigate a discrete model consisting of self-propelled particles that
obey simple interaction rules. We show that this model can self-organize and
exhibit coherent localized solutions in one- and in two-dimensions.In
one-dimension, the self-organized solution is a localized flock of finite
extent in which the density abruptly drops to zero at the edges.In
two-dimensions, we focus on the vortex solution in which the particles rotate
around a common center and show that this solution can be obtained from random
initial conditions, even in the absence of a confining boundary. Furthermore,
we develop a continuum version of our discrete model and demonstrate that the
agreement between the discrete and the continuum model is excellent.Comment: 4 pages, 5 figure
Towards dialogue: audio feedback on politics essays
This paper evaluates the use of audio feedback on assignments through the case study of a politics course, highlighting a number of pedagogical benefits. In particular, and using student testimonies, it argues that audio feedback provides a more personal feel to feedback; criticism, it appears, is easier to accept in the spoken word – as one student suggests, you know the marker is ‘not being harsh’ and is ‘just trying to help you really’. In addition, the paper notes the chief practical benefit of audio feedback: it reduces the overall time spent by lecturers in providing comments. While this paper is positive in favour of audio feedback throughout, it also discusses some potential challenges including anonymous marking – which affects the relationship between marker and student – and the fact that one size does not fit all, with different students preferring different types of feedback. The paper also attempts to provide practical tips to professionals wishing to use this method of feedback
Avalanche photodiodes for the CMS electromagnetic calorimeter
Avalanche photodiodes(APD's) will be used as photodetectors in the CMS barrel electromagnetic crystal calorimeter for high precision energy measurements in a hostile radiation environment. Significant progress has been made in the characteristics of these devices being expressly developed for CMS. Parameters of the final structure APD's together with demonstrations of radiation hardness and plans for quality assurance/control during the production phase are presented
Small-molecule Bcl-2 inhibitors sensitise tumour cells to immune-mediated destruction
The cytotoxic effects of anticancer immune cells are mediated by perforin/granzyme-B, Fas ligand and tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), and therefore depend on intact apoptotic responses in target tumour cells. As killing by all three of these mechanisms is blocked by the frequently overexpressed antiapoptotic oncoprotein Bcl-2, we hypothesised that coexposure to a Bcl-2 inhibitor might enhance anticancer immune responses. We evaluated this in U937 lymphoma cells, and A02 melanoma cells, which both show strong Bcl-2 expression. Vα24+ Vβ11+ natural killer T (NKT) cells expanded from peripheral blood of normal donors (n=3) were coincubated with PKH26-labelled U937 cells, and cytotoxicity was determined by flow cytometry after annexin-V-FITC and 7-AAD staining. In all cases, addition of the HA14-1 small-molecule Bcl-2 inhibitor to the cocultures significantly increased apoptosis in the target U937 cells. Using a similar assay, killing of A02 cells by the cytotoxic T-lymphocyte clone 1H3 was shown to be amplified by coexposure to the potent small-molecule Bcl-2 inhibitor ABT-737. Experiments with immune effectors preincubated with concanamycin-A suggested that sensitisation to perforin/granzyme-B may underlie enhanced target-cell killing observed in the presence of Bcl-2 inhibitors. We conclude that immune destruction of malignant cells can be amplified by molecular interventions that overcome Bcl-2-mediated resistance to apoptosis
Using Innovation-Corps (I-Corpsâ„¢) methods to adapt a mobile health (mHealth) obesity treatment for community mental health settings
BACKGROUND: We employed Innovation Corps (I-Corpsâ„¢) methods to adaptation of a mobile health (mHealth) short-message-system (SMS) -based interactive obesity treatment approach (iOTA) for adults with severe mentall illness receiving care in community settings.
METHODS: We hypothesized jobs to be done in three broad stakeholder groups: decision makers (DM = state and community clinic administrators), clinician consumers (CC = case managers, peer supports, nurses, prescribers) and service consumers (SC = patients, peers and family members). Semistructured interviews (
RESULTS: Four themes emerged across groups: education, inertia, resources and ownership. Sub-themes in education and ownership differed between DM and CC groups on implementation ownership, intersecting with professional development, suggesting the importance of training and supervision in scalability. Sub-themes in resources and intertia differed between CC and SC groups, suggesting illness severity and access to healthy food as major barriers to engagement, whereas the SC group identified the need for enhanced emotional support, in addition to pragmatic skills like menu planning and cooking, to promote health behavior change. Although SMS was percieved as a viable education and support tool, CC and DM groups had limited familiarity with use in clinical care delivery.
CONCLUSIONS: Based on customer discovery, the characteristics of a minimum viable iOTA for implementation, scalability and sustainability include population- and context-specific adaptations to treatment content, interventionist training and delivery mechanism. Successful implementation of an SMS-based intervention will likely require micro-adaptations to fit specific clinical settings
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