640 research outputs found

    Relativistic Modification of Newtonian Gravity Law

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    We show how Newtonian gravity with effective (actually observed) masses, obeying the mass-energy relation of special relativity, can explain all observations used to test General relativity. Dynamics of a gravitationally coupled binary system is considered in detail and the effective masses of constituents are determined. Interpreting our results in terms of motion in a curved space-time background, we are led, using the Lagrangian formalism, to consider the exponential metric as a natural space-time metric of Newtonian gravity

    On the Eigenvalue Problem of the Dirac Hamiltonian in a Singular Spacetime Background

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    We studied the motion of a spin onehalf particle in a singular spacetime metric of exponential type. This singular spacetime metric is obtained from a particular interpretation of the Newtonian gravitational force. For a given energy, the motion of a particle is described by the eigenvalue modes of the Dirac operator in a singular space time metric of exponential type. In this paper only the first order solution is considered leading to a cubic algebraic equation for energy eigenvalue. A novel interpretation for a gravitational atom is obtained

    MUSIC THERAPY AND MENTAL HEALTH IN PREGNANCY

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    Introduction: cant physiological, biochemical, and psychological changes that can affect mental health status. Participation in preventive activities during pregnancy has an impact on better emotional state after childbirth. Discussion: The therapeutic effects of listening to music on the health of mother and child have been proven in numerous studies. Listening to music during pregnancy contributes to a better sense of well - being and less pronounced symptoms of postpartum depression. Scientific evidence confirms the effects of music therapy on the level of stress and anxiety in pregnant women, but also calmer children and better emotional bonding. The application of GIM therapy music - induced imagination - also provides significant results in strengthening psychological resilience. Conclusion: Music therapy is a simple, non - pharmacological and safe method that significantly contributes to mental health in pregnancy and after childbirth. The application of music therapy has a scientific potential that offers many ideas for the development of medical - music research

    Crackling Noise, Power Spectra and Disorder Induced Critical Scaling

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    Crackling noise is observed in many disordered non-equilibrium systems in response to slowly changing external conditions. Examples range from Barkhausen noise in magnets to acoustic emission in martensites to earthquakes. Using the non-equilibrium random field Ising model, we derive universal scaling predictions for the dependence of the associated power spectra on the disorder and field sweep rate, near an underlying disorder-induced non-equilibrium critical point. Our theory applies to certain systems in which the crackling noise results from avalanche-like response to a (slowly) increasing external driving force, and is characterized by a broad power law scaling regime of the power spectra. We compute the critical exponents and discuss the relevance of the results to experiments.Comment: 27 Latex Pages, 14 eps figure

    Self-organized criticality in the hysteresis of the Sherrington - Kirkpatrick model

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    We study hysteretic phenomena in random ferromagnets. We argue that the angle dependent magnetostatic (dipolar) terms introduce frustration and long range interactions in these systems. This makes it plausible that the Sherrington - Kirkpatrick model may be able to capture some of the relevant physics of these systems. We use scaling arguments, replica calculations and large scale numerical simulations to characterize the hysteresis of the zero temperature SK model. By constructing the distribution functions of the avalanche sizes, magnetization jumps and local fields, we conclude that the system exhibits self-organized criticality everywhere on the hysteresis loop.Comment: 4 pages, 4 eps figure

    Effects of ischaemic conditioning on major clinical outcomes in people undergoing invasive procedures: systematic review and meta-analysis.

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    OBJECTIVE:  To summarise the benefits and harms of ischaemic conditioning on major clinical outcomes in various settings. DESIGN:  Systematic review and meta-analysis. DATA SOURCES:  Medline, Embase, Cochrane databases, and International Clinical Trials Registry platform from inception through October 2015. STUDY SELECTION:  All randomised controlled comparisons of the effect of ischaemic conditioning on clinical outcomes were included. DATA EXTRACTION:  Two authors independently extracted data from individual reports. Reports of multiple intervention arms were treated as separate trials. Random effects models were used to calculate summary estimates for all cause mortality and other pre-specified clinical outcomes. All cause mortality and secondary outcomes with P<0.1 were examined for study quality by using the GRADE assessment tool, the effect of pre-specified characteristics by using meta-regression and Cochran C test, and trial sequential analysis by using the Copenhagen Trial Unit method. RESULTS:  85 reports of 89 randomised comparisons were identified, with a median 80 (interquartile range 60-149) participants and median 1 (range 1 day-72 months) month intended duration. Ischaemic conditioning had no effect on all cause mortality (68 comparisons; 424 events; 11 619 participants; risk ratio 0.96, 95% confidence interval 0.80 to 1.16; P=0.68; moderate quality evidence) regardless of the clinical setting in which it was used or the particular intervention related characteristics. Ischaemic conditioning may reduce the rates of some secondary outcomes including stroke (18 trials; 5995 participants; 149 events; risk ratio 0.72, 0.52 to 1.00; P=0.048; very low quality evidence) and acute kidney injury (36 trials; 8493 participants; 1443 events; risk ratio 0.83, 0.71 to 0.97; P=0.02; low quality evidence), although the benefits seem to be confined to non-surgical settings and to mild episodes of acute kidney injury only. CONCLUSIONS:  Ischaemic conditioning has no overall effect on the risk of death. Possible effects on stroke and acute kidney injury are uncertain given methodological concerns and low event rates. Adoption of ischaemic conditioning cannot be recommended for routine use unless further high quality and well powered evidence shows benefit

    The winds and currents mission concept

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    © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Rodriguez, E., Bourassa, M., Chelton, D., Farrar, J. T., Long, D., Perkovic-Martin, D., & Samelson, R. The winds and currents mission concept. Frontiers in Marine Science, 6, (2019): 438, doi:10.3389/fmars.2019.00438.The Winds and Currents Mission (WaCM) is a proposed approach to meet the need identified by the NRC Decadal Survey for the simultaneous measurements of ocean vector winds and currents. WaCM features a Ka-band pencil-beam Doppler scatterometer able to map ocean winds and currents globally. We review the principles behind the WaCM measurement and the requirements driving the mission. We then present an overview of the WaCM observatory and tie its capabilities to other OceanObs reviews and measurement approaches.ER was funded under NASA grant NNN13D462T. DC was funded under NASA grant NNX10AO98G. JF was funded under NASA grants NNX14AM71G and NNX16AH76G. DL was funded under NASA grant NNX14AM67G. DP-M was funded under NASA grant NNH13ZDA001N. RS was funded under NASA grant NNX14AM66G
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