Symmetry breaking in the self-consistent Kohn-Sham equations

The Kohn-Sham (KS) equations determine, in a self-consistent way, the particle density of an interacting fermion system at thermal equilibrium. We consider a situation when the KS equations are known to have a unique solution at high temperatures and this solution is a uniform particle density. We show that, at zero temperature, there are stable solutions that are not uniform. We provide the general principles behind this phenomenon, namely the conditions when it can be observed and how to construct these non-uniform solutions. Two concrete examples are provided, including fermions on the sphere which are shown to crystallize in a structure that resembles the C$_{60}$ molecule.Comment: a few typos eliminate

Case Study of a Comprehensive Team-Based Approach to Increase Colorectal Cancer Screening

Introduction: Colorectal cancer is the second leading cause of cancer deaths among men and women in West Virginia. In addition, 51% of all colorectal cancers diagnosed in West Virginia from 2012 to 2016 were detected at either regional (31%) or distant (20%) stages indicating a need for improved early detection. Methods: West Virginia University Cheat Lake Physicians participated in the West Virginia Program to Increase Colorectal Cancer Screening, a program of Cancer Prevention and Control at the WVU Cancer Institute. As a result, Cheat Lake Physicians assembled a team of health care professionals to implement evidence-based interventions and system changes including provider assessment and feedback, patient reminders, accurate data capture, and tracking of CRC screening tests. Results: These efforts resulted in a 15.8% increase in colorectal cancer screening rates within one year of implementation. Additionally, the clinic achieved a 66% return rate for Fecal Immunochemical Test kits, an inexpensive, stool-based colorectal cancer screening test. Implications: The utilization of a team-based approach to patient care yields positive results that can be carried over to other cancer and disease prevention efforts in primary care clinics

Dimensional crossover of the fundamental-measure functional for parallel hard cubes

We present a regularization of the recently proposed fundamental-measure functional for a mixture of parallel hard cubes. The regularized functional is shown to have right dimensional crossovers to any smaller dimension, thus allowing to use it to study highly inhomogeneous phases (such as the solid phase). Furthermore, it is shown how the functional of the slightly more general model of parallel hard parallelepipeds can be obtained using the zero-dimensional functional as a generating functional. The multicomponent version of the latter system is also given, and it is suggested how to reformulate it as a restricted-orientation model for liquid crystals. Finally, the method is further extended to build a functional for a mixture of parallel hard cylinders.Comment: 4 pages, no figures, uses revtex style files and multicol.sty, for a PostScript version see http://dulcinea.uc3m.es/users/cuesta/cross.p

Leveraging Electronic Health Records Data for Enhanced Colorectal Cancer Screening Efforts

Introduction: Colorectal cancer is the third most common type of cancer in the United States for men and women combined. While the current threat of disease nationally is significant, the majority of colorectal cancer cases and deaths could be prevented through established screening tests and guidelines. Within the Appalachian region and West Virginia in particular, colorectal cancer is a significant public health problem. A more systematic, comprehensive approach to preventing and controlling cancer is essential. Methods: Through the West Virginia Program to Increase Colorectal Cancer Screening, primary care systems across the state received data-informed practice facilitation designed to increase screening rates. Results: Year-1 cohort health systems had an overall baseline screening rate of 28.4% during calendar year 2014. This rate increased and remained steady during the three follow-up measurement time periods, with a rate of 49.5% during calendar year 2018. This increase is notably greater than comparable health systems not part of the initiative. Implications: Lessons learned in increasing colorectal cancer screening rates are applicable to other priority health needs as well

PONV Prophylaxis Failure Disproportionately Affects Female Patients, Despite Intraoperative Computerized Decision Support Guidance

Objectives: To compare postoperative nausea and vomiting (PONV) prophylaxis treatment and outcomes based on patients’ sex, using a retrospective cohort. The setting was the operating room and post-anesthesia care unit of a tertiary care university medical center. Patients: A total of 678 adult male and female patients with American Society of Anesthesiologist (ASA) scores of 1-4 underwent surgery with general anesthesia. All patients received preoperative PONV risk assessment. PONV prophylaxis was administered at the discretion of the anesthesia care team members with guidance from a computerized decision support system. Measurements: Adequacy of prophylaxis was retrospectively determined based on individual patient risk factors and the observed treatment received, compared with guideline-based prophylaxis recommendations. Patient outcome was measured by diagnosis of PONV in recovery. Results: Comparing patients who received fewer than the guideline-recommended number of prophylactic antiemetics by sex, 94.6% were female and 5.4% were males (p \u3c 0.001). Patients who received fewer than guideline-recommended number of antiemetics had significantly higher rates of nausea or vomiting in the post-anesthesia care unit (30.4% vs 17.5%, p \u3c 0.001). Conclusion: This retrospective cohort study shows that female patients receiving general anesthesia are disproportionately affected by failure to adhere to PONV prevention guidelines

The 2-D electron gas at arbitrary spin polarizations and arbitrary coupling strengths: Exchange-correlation energies, distribution functions and spin-polarized phases

We use a recent approach [Phys. Rev. Letters, {\bf 84}, 959 (2000)] for including Coulomb interactions in quantum systems via a classical mapping of the pair-distribution functions (PDFs) for a study of the 2-D electron gas. As in the 3-D case, the ``quantum temperature'' T_q of a classical 2-D Coulomb fluid which has the same correlation energy as the quantum fluid is determined as a function of the density parameter r_s. Spin-dependent exchange-correlation energies are reported. Comparisons of the spin-dependent pair-distributions and other calculated properties with any available 2-D quantum Monte Carlo (QMC) results show excellent agreement, strongly favouring more recent QMC data. The interesting novel physics brought to light by this study are: (a) the independently determined quantum-temperatures for 3-D and 2-D are found to be approximately the same, (i.e, universal) function of the classical coupling constant Gamma. (b) the coupling constant Gamma increases rapidly with r_s in 2-D, making it comparatively more coupled than in 3-D; the stronger coupling in 2-D requires bridge corrections to the hyper- netted-chain method which is adequate in 3-D; (c) the Helmholtz free energy of spin-polarized and unpolarized phases have been calculated. The existence of a spin-polarized 2-D liquid near r_s = 30, is found to be a marginal possibility. These results pertain to clean uniform 2-D electron systems.Comment: This paper replaces the cond-mat/0109228 submision; the new version include s more accurate numerical evaluation of the Helmholtz energies of the para- and ferromagentic 2D fluides at finite temperatures. (Paper accepted for publication in Phys. Rev. Lett.

Teaching breast ultrasound skills including core-needle biopsies on a phantom enhances undergraduate student's knowledge and learning satisfaction

Purpose To investigate whether a training program on breast ultrasound skills including core-needle biopsies to undergraduate students can improve medical knowledge and learning satisfaction. Methods Medical students attending mandatory classes at the Medical School of the University of Saarland received a supplemental theoretical and hands-on training program on ultrasound (US) breast screening and on US-guided core-needle biopsy using an agar–agar phantom. Experienced breast specialists and ultrasound examiners served as trainers applying Peyton’s 4-step training approach. The students’ theoretical knowledge and hands-on skills were tested before and after the training program, using a multiple-choice questionnaire (MCQ), the Objective Structured Clinical Examination (OSCE) and a student curriculum evaluation. Results The MCQ results showed a significant increase of the student’s theoretical knowledge (50.2–75.2%, p < 0.001). After the course, the OSCE showed a mean total of 17.3/20 points (86.5%), confirming the practical implementation of the new skills. The student curriculum evaluation in general was very positive. A total of 16/20 questions were rated between 1.2 and 1.7 (very good) and 3 questions were rated as 2.1 (good). Conclusion Undergraduate student’s medical education can be enhanced by teaching breast US skills

User-centred design of flexible hypermedia for a mobile guide: Reflections on the hyperaudio experience

A user-centred design approach involves end-users from the very beginning. Considering users at the early stages compels designers to think in terms of utility and usability and helps develop the system on what is actually needed. This paper discusses the case of HyperAudio, a context-sensitive adaptive and mobile guide to museums developed in the late 90s. User requirements were collected via a survey to understand visitors’ profiles and visit styles in Natural Science museums. The knowledge acquired supported the specification of system requirements, helping defining user model, data structure and adaptive behaviour of the system. User requirements guided the design decisions on what could be implemented by using simple adaptable triggers and what instead needed more sophisticated adaptive techniques, a fundamental choice when all the computation must be done on a PDA. Graphical and interactive environments for developing and testing complex adaptive systems are discussed as a further step towards an iterative design that considers the user interaction a central point. The paper discusses how such an environment allows designers and developers to experiment with different system’s behaviours and to widely test it under realistic conditions by simulation of the actual context evolving over time. The understanding gained in HyperAudio is then considered in the perspective of the developments that followed that first experience: our findings seem still valid despite the passed time

Renormalized kinetic theory of classical fluids in and out of equilibrium

We present a theory for the construction of renormalized kinetic equations to describe the dynamics of classical systems of particles in or out of equilibrium. A closed, self-consistent set of evolution equations is derived for the single-particle phase-space distribution function $f$, the correlation function $C=$, the retarded and advanced density response functions $\chi^{R,A}=\delta f/\delta\phi$ to an external potential $\phi$, and the associated memory functions $\Sigma^{R,A,C}$. The basis of the theory is an effective action functional $\Omega$ of external potentials $\phi$ that contains all information about the dynamical properties of the system. In particular, its functional derivatives generate successively the single-particle phase-space density $f$ and all the correlation and density response functions, which are coupled through an infinite hierarchy of evolution equations. Traditional renormalization techniques are then used to perform the closure of the hierarchy through memory functions. The latter satisfy functional equations that can be used to devise systematic approximations. The present formulation can be equally regarded as (i) a generalization to dynamical problems of the density functional theory of fluids in equilibrium and (ii) as the classical mechanical counterpart of the theory of non-equilibrium Green's functions in quantum field theory. It unifies and encompasses previous results for classical Hamiltonian systems with any initial conditions. For equilibrium states, the theory reduces to the equilibrium memory function approach. For non-equilibrium fluids, popular closures (e.g. Landau, Boltzmann, Lenard-Balescu) are simply recovered and we discuss the correspondence with the seminal approaches of Martin-Siggia-Rose and of Rose.and we discuss the correspondence with the seminal approaches of Martin-Siggia-Rose and of Rose.Comment: 63 pages, 10 figure

Equation of state of fully ionized electron-ion plasmas

Thermodynamic quantities of Coulomb plasmas consisting of point-like ions immersed in a compressible, polarizable electron background are calculated for ion charges Z=1 to 26 and for a wide domain of plasma parameters ranging from the Debye-Hueckel limit to the crystallization point and from the region of nondegenerate to fully degenerate nonrelativistic or relativistic electrons. The calculations are based on the linear-response theory for the electron-ion interaction, including the local-field corrections in the electronic dielectric function. The thermodynamic quantities are calculated in the framework of the N-body hypernetted-chain equations and fitted by analytic expressions. We present also accurate analytic approximations for the free energy of the ideal electron gas at arbitrary degeneracy and relativity and for the excess free energy of the one-component plasma of ions (OCP) derived from Monte Carlo simulations. The extension to multi-ionic mixtures is discussed within the framework of the linear mixing rule. These formulae provide a completely analytic, accurate description of the thermodynamic quantities of fully ionized electron-ion Coulomb plasmas, a useful tool for various applications from liquid state theory to dense stellar matter.Comment: 13 pages, 2 tables, 7 figures, REVTeX using epsf.sty. To be published in Phys. Rev. E, vol. 58 (1998