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"Stevens, Michael"
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Statistical Analysis of the Radial Evolution of the Solar Winds between 0.1 and 1 au and Their Semiempirical Isopoly Fluid Modeling
Statistical classification of the Helios solar wind observations into several populations sorted by bulk speed has revealed an outward acceleration of the wind. The faster the wind, the smaller this acceleration in the 0.3–1 au radial range. In this paper, we show that recent measurements from the Parker Solar Probe (PSP) are compatible with an extension closer to the Sun of the latter Helios classification. For instance, the well-established bulk speed/proton temperature (u, T p) correlation and bulk speed/electron temperature (u, T e) anticorrelation, together with the acceleration of the slowest winds, are verified in PSP data. We also model the combined PSP and Helios data using empirical Parker-like models for which the solar wind undergoes an “isopoly” expansion: isothermal in the corona, then polytropic at distances larger than the sonic point radius. The polytropic indices are derived from the observed temperature and density gradients. Our modeling reveals that the electron thermal pressure has a major contribution in the acceleration process of slow and intermediate winds (in the range of 300–500 km s−1 at 1 au) over a broad range of distances and that the global (electron and proton) thermal energy alone is able to explain the acceleration profiles. Moreover, we show that the very slow solar wind requires, in addition to the observed pressure gradients, another source of acceleration.
Journal Article
Driver acceptance of new technology : theory, measurement and optimisation
\"Acceptance of new technology and systems by drivers is an important area of concern to governments, automotive manufacturers and equipment suppliers, especially technology that has significant potential to enhance safety. To be acceptable, new technology must be useful and satisfying to use. If not, drivers will not want to have it, in which case it will never achieve the intended safety benefit. Even if they have the technology, drivers may not use it if it is deemed unacceptable, or may not use it in the manner intended by the designer. At worst, they may seek to disable it\"-Provided by publisher.
Book
The Effects of Nonequilibrium Velocity Distributions on Alfvén Ion-cyclotron Waves in the Solar Wind
In this work, we investigate how the complex structure found in solar wind proton velocity distribution functions (VDFs), rather than the commonly assumed two-component bi-Maxwellian structure, affects the onset and evolution of parallel-propagating microinstabilities. We use the Arbitrary Linear Plasma Solver, a numerical dispersion solver, to find the real frequencies and growth/damping rates of the Alfvén modes calculated for proton VDFs extracted from Wind spacecraft observations of the solar wind. We compare this wave behavior to that obtained by applying the same procedure to core-and-beam bi-Maxwellian fits of the Wind proton VDFs. We find several significant differences in the plasma waves obtained for the extracted data and bi-Maxwellian fits, including a strong dependence of the growth/damping rate on the shape of the VDF. By applying the quasilinear diffusion operator to these VDFs, we pinpoint resonantly interacting regions in velocity space where differences in VDF structure significantly affect the wave growth and damping rates. This demonstration of the sensitive dependence of Alfvén mode behavior on VDF structure may explain why the Alfvén ion-cyclotron instability thresholds predicted by linear theory for bi-Maxwellian models of solar wind proton background VDFs do not entirely constrain spacecraft observations of solar wind proton VDFs, such as those made by the Wind spacecraft.
Journal Article
عقول الفتيان : حماية أبنائنا من التخلف عن غيرهم في المدرسة وفي الحياة
يفيد هذا الكتاب بتوضيح الصورة المتعلقة بحاجات الفتيان على الصعد الاجتماعية والعاطفية والجسدية والذهنية. من الضروري أن يطالع هذا الكتاب جميع المربين والمعلمين في جميع المراحل المدرسية ابتداءا من المراحل التمهيدية وصولا إلى التكميلية والثانوية كما يجب على جميع الآباء والأمهات والأجداد والجدات أن يقرؤوا هذا الكتاب وذلك لتربية أبنائهم وأحفادهم بالطرق المثلى.
Book
Clinical Decision Support Systems and Their Role in Antibiotic Stewardship: a Systematic Review
Purpose of ReviewThe purpose of this article is to perform a systematic review over the past 5 years on the role and effectiveness of clinical decision support systems (CDSSs) on antibiotic stewardship.Recent FindingsCDDS interventions found a significant impact on multiple outcomes relevant to antibiotic stewardship. There are various types of CDSS implementations, both active and passive (provider initiated). Passive interventions were associated with more significant outcomes; however, both interventions appeared effective. In the reviewed literature, CDSSs were consistently associated with decreasing antibiotic consumption and narrowing the spectrum of antibiotic usage. Generally, guideline adherence was improved with CDSS, although this was not universal. The effect on other outcomes, such as mortality, Clostridiodes difficile infections, length of stay, and cost, inconsistently showed a significant difference.SummaryOverall, CDDS implementation has effectively decreased antibiotic consumption and improved guideline adherence across the various types of CDSS. Other positive outcomes were noted in certain settings, but were not universal. When creating a new intervention, it is important to identify the optimal structure and deployment of a CDSS for a specific setting.
Journal Article