3,261 research outputs found
Dynamical Scaling Behavior of Percolation Clusters in Scale-free Networks
In this work we investigate the spectra of Laplacian matrices that determine
many dynamic properties of scale-free networks below and at the percolation
threshold. We use a replica formalism to develop analytically, based on an
integral equation, a systematic way to determine the ensemble averaged
eigenvalue spectrum for a general type of tree-like networks. Close to the
percolation threshold we find characteristic scaling functions for the density
of states rho(lambda) of scale-free networks. rho(lambda) shows characteristic
power laws rho(lambda) ~ lambda^alpha_1 or rho(lambda) ~ lambda^alpha_2 for
small lambda, where alpha_1 holds below and alpha_2 at the percolation
threshold. In the range where the spectra are accessible from a numerical
diagonalization procedure the two methods lead to very similar results.Comment: 9 pages, 6 figure
One-body dissipation and chaotic dynamics in a classical simulation of a nuclear gas
In order to understand the origin of one-body dissipation in nuclei, we
analyze the behavior of a gas of classical particles moving in a
two-dimensional cavity with nuclear dimensions. This "nuclear" billiard has
multipole-deformed walls which undergo periodic shape oscillations. We
demonstrate that a single particle Hamiltonian containing coupling terms
between the particles' motion and the collective coordinate induces a chaotic
dynamics for any multipolarity, independently on the geometry of the billiard.
If the coupling terms are switched off the "wall formula" predictions are
recovered. We discuss the dissipative behavior of the wall motion and its
relation with the order-to-chaos transition in the dynamics of the microscopic
degrees of freedom.Comment: 16 pages, 12 postscript figures included, revtex, new version
completely revised accepted by Physical Review C and scheduled to appear in
the issue of november 199
Child-Abuse-Related-Deaths, Child Mortality (0-4) & Income Inequality in America and Other Developed Nations 1989-91 v 2012-14: Speaking Truth to Power.
The major concern for social work, namely child abuse‐related deaths (CARD), involves parental neglect. Societal neglect, when measured by child mortality rates (CMR), is considered by bodies such as UNICEF to be indicative of how a nation meets the needs of its children. This population‐based study analyses CARD and CMR for children aged from newborn to four years old between 1989–91 and 2013–15 to identify any relative child neglect in the USA and 20 other developed nations (ODN).
World Health Organization data were used for CARD, CMR and undetermined deaths (UnD), a possible source of unreported CARD, juxtaposed against World Bank income inequality data.
The USA had the highest number of CARD, the highest CMR and the worst income inequality. Five countries reduced their CARD significantly more than the USA, and 14 countries reduced their CMR more than the USA. Income inequality and CMR were correlated.
Had the USA matched the CMR of Japan, where income inequality was narrowest, there would have been on average 16 745 fewer child deaths annually.
CARD and UnD correlated, suggesting that UnD may contain unreported CARD. US CMR data indicate that services in the USA are less effective than those in ODN, possibly due to income inequality. These results will be unwelcome but child protection services must dare to speak truth to power.
‘This population‐based study analyses CARD and CMR for children aged from newborn to four years old between 1989–91 and 2013–15 to identify any relative child neglect in the USA and 20 other developed nations’
Key Practitioner Messages
The richest country in the world, the USA, has the highest rates of child abuse and total child mortality in the Western world.
The USA has the highest income inequality in the West, highlighting the statistical link between child mortality and poverty.
Children's services should lead the call for the necessary changes and ‘speak truth to power’
Large Orbital Magnetic Moment and Coulomb Correlation effects in FeBr2
We have performed an all-electron fully relativistic density functional
calculation to study the magnetic properties of FeBr2. We show for the first
time that the correlation effect enhances the contribution from orbital degrees
of freedom of electrons to the total magnetic moment on Fe as
opposed to common notion of nearly total quenching of the orbital moment on
Fe site. The insulating nature of the system is correctly predicted when
the Hubbard parameter U is included. Energy bands around the gap are very
narrow in width and originate from the localized Fe-3 orbitals, which
indicates that FeBr2 is a typical example of the Mott insulator.Comment: 4 pages, 3 figures, revtex4, PRB accepte
Bethe ansatz for the Harper equation: Solution for a small commensurability parameter
The Harper equation describes an electron on a 2D lattice in magnetic field
and a particle on a 1D lattice in a periodic potential, in general,
incommensurate with the lattice potential. We find the distribution of the
roots of Bethe ansatz equations associated with the Harper equation in the
limit as alpha=1/Q tends to 0, where alpha is the commensurability parameter (Q
is integer). Using the knowledge of this distribution we calculate the higher
and lower boundaries of the spectrum of the Harper equation for small alpha.
The result is in agreement with the semiclassical argument, which can be used
for small alpha.Comment: 17 pages including 5 postscript figures, Latex, minor changes, to
appear in Phys.Rev.
Wavepacket reconstruction via local dynamics in a parabolic lattice
We study the dynamics of a wavepacket in a potential formed by the sum of a
periodic lattice and of a parabolic potential. The dynamics of the wavepacket
is essentially a superposition of ``local Bloch oscillations'', whose frequency
is proportional to the local slope of the parabolic potential. We show that the
amplitude and the phase of the Fourier transform of a signal characterizing
this dynamics contains information about the amplitude and the phase of the
wavepacket at a given lattice site. Hence, {\em complete} reconstruction of the
the wavepacket in the real space can be performed from the study of the
dynamics of the system.Comment: 4 pages, 3 figures, RevTex
Comprehensive plasma proteomic profiling reveals biomarkers for active tuberculosis
BACKGROUND. Tuberculosis (TB) kills more people than any other infection, and new diagnostic tests to identify active cases are required. We aimed to discover and verify novel markers for TB in nondepleted plasma. /
METHODS. We applied an optimized quantitative proteomics discovery methodology based on multidimensional and orthogonal liquid chromatographic separation combined with high-resolution mass spectrometry to study nondepleted plasma of 11 patients with active TB compared with 10 healthy controls. Prioritized candidates were verified in independent UK (n = 118) and South African cohorts (n = 203). /
RESULTS. We generated the most comprehensive TB plasma proteome to date, profiling 5022 proteins spanning 11 orders-of-magnitude concentration range with diverse biochemical and molecular properties. We analyzed the predominantly low–molecular weight subproteome, identifying 46 proteins with significantly increased and 90 with decreased abundance (peptide FDR ≤ 1%, q ≤ 0.05). Verification was performed for novel candidate biomarkers (CFHR5, ILF2) in 2 independent cohorts. Receiver operating characteristics analyses using a 5-protein panel (CFHR5, LRG1, CRP, LBP, and SAA1) exhibited discriminatory power in distinguishing TB from other respiratory diseases (AUC = 0.81). /
CONCLUSION. We report the most comprehensive TB plasma proteome to date, identifying novel markers with verification in 2 independent cohorts, leading to a 5-protein biosignature with potential to improve TB diagnosis. With further development, these biomarkers have potential as a diagnostic triage test. /
FUNDING. Colciencias, Medical Research Council, Innovate UK, NIHR, Academy of Medical Sciences, Program for Advanced Research Capacities for AIDS, Wellcome Centre for Infectious Diseases Research
Implementing health research through academic and clinical partnerships : a realistic evaluation of the Collaborations for Leadership in Applied Health Research and Care (CLAHRC)
Background: The English National Health Service has made a major investment in nine partnerships between
higher education institutions and local health services called Collaborations for Leadership in Applied Health
Research and Care (CLAHRC). They have been funded to increase capacity and capability to produce and
implement research through sustained interactions between academics and health services. CLAHRCs provide a
natural ‘test bed’ for exploring questions about research implementation within a partnership model of delivery.
This protocol describes an externally funded evaluation that focuses on implementation mechanisms and
processes within three CLAHRCs. It seeks to uncover what works, for whom, how, and in what circumstances.
Design and methods: This study is a longitudinal three-phase, multi-method realistic evaluation, which
deliberately aims to explore the boundaries around knowledge use in context. The evaluation funder wishes to see
it conducted for the process of learning, not for judging performance. The study is underpinned by a conceptual
framework that combines the Promoting Action on Research Implementation in Health Services and Knowledge to
Action frameworks to reflect the complexities of implementation. Three participating CLARHCS will provide indepth
comparative case studies of research implementation using multiple data collection methods including
interviews, observation, documents, and publicly available data to test and refine hypotheses over four rounds of
data collection. We will test the wider applicability of emerging findings with a wider community using an
interpretative forum.
Discussion: The idea that collaboration between academics and services might lead to more applicable health
research that is actually used in practice is theoretically and intuitively appealing; however the evidence for it is
limited. Our evaluation is designed to capture the processes and impacts of collaborative approaches for
implementing research, and therefore should contribute to the evidence base about an increasingly popular (e.g.,
Mode two, integrated knowledge transfer, interactive research), but poorly understood approach to knowledge
translation. Additionally we hope to develop approaches for evaluating implementation processes and impacts
particularly with respect to integrated stakeholder involvement
Losartan to slow the progression of mild-to-moderate Alzheimer's disease through angiotensin targeting: the RADAR RCT
BACKGROUND: Medications that modify the renin–angiotensin system may reduce Alzheimer’s disease pathology and reduce the rate of disease progression. OBJECTIVE: This study investigated whether taking the antihypertensive drug losartan, in addition to normal care, would slow the progression of Alzheimer’s disease when compared with a placebo. DESIGN: A double-blind multicentre randomised controlled trial, after a 4-week open-label phase, with follow-up at 14 days and at 3, 6, 9 and 12 months. The primary outcome was based on measured imaging differences in brain volume between baseline and 12 months. SETTING: Twenty-three NHS hospital trusts across England, Scotland and Northern Ireland. PARTICIPANTS: Patients diagnosed with mild-to-moderate Alzheimer’s disease were eligible to participate if they met the following criteria: (1) aged ≥ 55 years; (2) a Mini Mental State Examination score of 15–28; (3) a modified Hachinski Ischaemic Score of ≤ 5; (4) a previous computerised tomography, single-photon emission computed tomography or magnetic resonance imaging scan consistent with a diagnosis of Alzheimer’s disease; (5) a study companion who was willing to participate in the study; and (6) capacity to consent for themselves. Patients were ineligible if they were (1) taking or intolerant to renin–angiotensin system-related medications, (2) unlikely to undergo magnetic resonance imaging or (3) unlikely to complete the trial protocol. People who had blood pressure outside the normal ranges, defined cardiovascular issues, impaired liver or renal function, or a primary neurodegenerative disease that was not Alzheimer’s disease were also excluded, as were women who had not reached menopause and were unwilling to take relevant protocol-specific safety precautions. INTERVENTION: The intervention was either 100 mg of overencapsulated losartan (Teva Pharmaceuticals Industries Ltd, Petah Tikva, Israel) daily or a matched placebo for 12 months. MAIN OUTCOMES AND MEASURES: Difference in brain atrophy, represented by measurement of whole-brain volume before and following 12 months of treatment post randomisation, was measured using volumetric MRI and determined by boundary shift interval analysis. Secondary outcomes included changes in rates of Alzheimer’s disease progression (as assessed using the ADAS-Cog, Mini Mental State Examination and Neuropsychiatric Inventory), the volume of white matter hyperintensities, cerebral blood flow (assessed by magnetic resonance imaging), blood pressure, magnetic resonance imaging measures of atrophy and association with measures of cognitive decline, and drug compliance and tolerability. RESULTS: A total of 261 participants entered the open-label phase, of whom 211 were randomised to the intervention (n = 105) or placebo (n = 106) arms. Of the 197 people (93%) who completed the study, 81% (n = 171) had a valid primary outcome. The difference in brain volume between arms was consistent with chance (–2.79 ml, 95% confidence interval –6.46 to 0.89 ml; p = 0.19), and there was no evidence of benefit for any of the secondary outcome measures. LIMITATIONS: Our study had 82% power to detect treatment-based changes and, as a result, may have been underpowered or, more likely, the intervention, which may not have crossed the blood–brain barrier as much as expected, may have been given too late or for an insufficient amount of time in the disease process to influence the outcomes. CONCLUSIONS: Losartan administered over 12 months did not alter brain atrophy in Alzheimer’s disease. FUTURE WORK: Other related ‘sartans’ could be tested in patient groups with mild cognitive impairment and for longer to fully test this hypothesis. TRIAL REGISTRATION: Current Controlled Trials ISRCTN93682878 and EudraCT 2012-003641-15. FUNDING: This project was funded by the Efficacy and Mechanism Evaluation (EME) programme, a Medical Research Council and National Institute for Health Research (NIHR) partnership. This will be published in full in Efficacy and Mechanism Evaluation; Vol. 8, No. 19. See the NIHR Journals Library website for further project information
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