Can one hear the shape of a saturation patch?

The theory of the acoustics of patchy-saturation in porous media is used to analyze experimental data on wave velocity and attenuation in partially water saturated limestones. It is demonstrated that the theory can be used to deduce the value of V/A, the ratio of the volume to area of the water patch, and l_f, the Poisson size of the water patch. One can ``hear'' the shape of a patch if the properties of the rock and the measurement frequencies are such as to satisfy the specific requirements for the validity of the theory

Friends at Mid-Century

The Isaac T. and Lida K. Johnson Lectureship, made possible by their gift, was created by the Executive Committee of the Five Years Meeting in its sessions of April, 1940. The creative minute of the Executive Committee is in part as follows: It is the duty of the Executive Committee to determine the use of this money and the Central Committee submits this recommendation: (1) that the gift be made a continuing memorial to these dear friends and (2) that the memorial be in the form of a lectureship for the Five Years Meeting, and, as it may direct, to be known as the Isaac T. and Lida K. Johnson Lectureship. It is further recommended that these lectures shall within the jurisdiction of the Executive Committee, be restricted to the field of Christian scholarship and the Christian message and its application to life. It is the confident expectation of the Executive Committee that not only the constituency of the Five Years Meeting, but all of Quakerism will be enriched by the successive messages made possible by this gift.https://digitalcommons.georgefox.edu/quakerbooks/1072/thumbnail.jp

Professional Learning Portfolios for Argumentation in School Science

This paper reports on the use of portfolios in a continuing professional development programme to advance teachers’ skills in their pedagogy of argumentation. The programme adopted a cyclical process of expert input- teacher practice- sharing practice, in order for professional learning to include reflective analysis of growing accomplishment. Accomplishment was initially defined according to previous research and development on the teaching of argumentation, but was redefined during the programme as teachers shared practice and discussed their achievements. Portfolios were used to help teachers apply their learning, collate evidence of their accomplishment and share reflective analysis of practice with other colleagues on the programme. The paper includes extracts of two teachers’ portfolios; these provide evidence of each teacher’s developing accomplishment in the teaching of argumentation. Portfolios are idiosyncratic and are constructed according to an individual teacher’s motivations, interpretations and situations. Teachers need structure and guidance in creating purposeful portfolios that enhance reflective practice

Chemically-Mediated quantum criticality in NbFe_2

Laves-phase Nb{1+c}Fe_{2-c} is a rare itinerant intermetallic compound exhibiting magnetic quantum criticality at c_{cr}=1.5%Nb excess; its origin, and how alloying mediates it, remains an enigma. For NbFe_2, we show that an unconventional band critical point (uBCP) above the Fermi level E_F explains most observations, and that chemical alloying mediates access to this uBCP by an increase in E_F with decreasing electrons (increasing %Nb), counter to rigid-band concepts. We calculate that E_F enters the uBCP region for c_{cr} > 1.5%Nb and by 1.74%Nb there is no Nb site-occupation preference between symmetry-distinct Fe sites, i.e., no electron-hopping disorder, making resistivity near constant as observed. At larger Nb (Fe) excess, the ferromagnetic Stoner criterion is satisfied.Comment: 4 pages, 5 figure

Quality of Life in Patients with Implantable Cardioverter Defibrillators

Background: The implantable cardioverter defibrillator (ICD) is a life saving device for individuals with life threatening ventricular arrhythmias. There is no doubt that it is a cost effective therapy in various congenital and acquired arrhythmogenic disorders. Nevertheless, shock delivery may be painful and frightening which causes psychological distress and deterioration of perceived quality of life. Methods: A systematic meta-analysis on studies reporting quality of life in patients implanted with ICDs was done using professional databases. Related articles and references of the relevant articles were also searched for suitable studies. Results: Thirty studies with a total of 3412 patients on implantable defibrillators were identified. Five of them were large randomised studies with a total of 1680 patients, while 25 were non-randomised studies. Medical Outcome Study 36-item Short Form health survey (SF - 36) was the most common instrument used for assessment of quality of life. Only one of the 5 major randomised trial reported worsening of quality of life after implantation of a defibrillator. In the subgroup of patients receiving shocks, three out of the five trials reported worsening of quality of life. Summary: Most of the randomised studies showed either neutral or better quality of life in patients on implantable defibrillators. In the subset of patients receiving shocks, worsening of quality of life was found in most randomised studies. Therefore, activation of antitachycardia pacing should be performed in every ICD-patient in order to miminze painful shocks and consequent deterioration of quality of life

Professional Learning Portfolios for Argumentation in School Science

This paper reports on the use of portfolios in a continuing professional development programme to advance teachers’ skills in their pedagogy of argumentation. The programme adopted a cyclical process of expert input- teacher practice- sharing practice, in order for professional learning to include reflective analysis of growing accomplishment. Accomplishment was initially defined according to previous research and development on the teaching of argumentation, but was redefined during the programme as teachers shared practice and discussed their achievements. Portfolios were used to help teachers apply their learning, collate evidence of their accomplishment and share reflective analysis of practice with other colleagues on the programme. The paper includes extracts of two teachers’ portfolios; these provide evidence of each teacher’s developing accomplishment in the teaching of argumentation. Portfolios are idiosyncratic and are constructed according to an individual teacher’s motivations, interpretations and situations. Teachers need structure and guidance in creating purposeful portfolios that enhance reflective practice

Ta-Nb-Mo-W refractory high-entropy alloys: anomalous ordering behavior and its intriguing electronic origin

From electronic-structure-based thermodynamic linear-response, we establish chemical ordering behavior in complex solid solutions versus how Gibbs' space is traversed -- applying it on prototype refractory A2 Ta-Nb-Mo-W high-entropy alloys. Near ideal stoichiometry, this alloy has anomalous, intricate chemical ordering tendencies, with long-ranged chemical interactions that produce competing short-range order (SRO) with a crossover to spinodal segregation. This atypical SRO arises from canonical band behavior that, with alloying, create features near the Fermi-surface (well-defined even with disorder) that change to simple commensurate SRO with (un)filling of these states. Our results reveal how complexity and competing electronic effects control ordering in these alloys.Comment: 6pages, 5 figure