324 research outputs found
Ways of going on:An analysis of skill applied to medical practice
Humans do two types of actions, polimorphic actions and mimeomorphic actions. The ability to carry out polimorphic actions cannot be mastered outside of socialization. Mimeomorphic actions, however, can be learned in other ways; sometimes, they can be learned away from the context of practice. Polimorphic actions cannot be mimicked by machines, but some mimeomorphic actions can. Other mimeomorphic actions are too complex to mechanize. Actions that cannot be mechanized because they are physically complicated should not be confused with actions that cannot be mechanized because socialization is needed to master them. The analysis has implications for recent debates concerning the differences and similarities between humans and machines. The implica tion of the analysis is that much more can be understood about the relationship between humans and machines if the difference is treated as being a consequence of the unique properties of human societies. In this article, the analysis is applied to cardiac catheteriza tion, pacemaker implantation, simulation of bodies, and work in a medical "SkillsLab.
Design and Operation of Gravity or Surface Systems (Chapter 13)
Surface irrigation uses open channel flow to spread water over a field.
The driving force in such systems is gravity and hence the alternate term,
gravity flooding. Once distributed over the surface of the field and after it has
entered the soil, water is often redistributed by forces other than gravity.
Surface irrigation systems generally require a smaller initial investment
than do other types of irrigation systems. However, this is not always the
case, especially if extensive land forming is needed for an efficient system. In
fact, the need for extensive land forming is one of the main reasons why other
types of irrigation systems have been developed
Exponential renormalization
Moving beyond the classical additive and multiplicative approaches, we
present an "exponential" method for perturbative renormalization. Using Dyson's
identity for Green's functions as well as the link between the Faa di Bruno
Hopf algebra and the Hopf algebras of Feynman graphs, its relation to the
composition of formal power series is analyzed. Eventually, we argue that the
new method has several attractive features and encompasses the BPHZ method. The
latter can be seen as a special case of the new procedure for renormalization
scheme maps with the Rota-Baxter property. To our best knowledge, although very
natural from group-theoretical and physical points of view, several ideas
introduced in the present paper seem to be new (besides the exponential method,
let us mention the notions of counterfactors and of order n bare coupling
constants).Comment: revised version; accepted for publication in Annales Henri Poincar
Anisotropic optical properties of single-crystal GdBa2Cu3O7-delta
The optical spectrum of reduced-T(c) GdBa2Cu3O7-delta has been measured for polarizations parallel and perpendicular to the ab plane. The sample was an oxygen-deficient single crystal with a large face containing the c axis. The polarized reflectance from this face was measured from 20-300 K in the spectral region from 30-3000 cm-1, with 300 K data to 30 000 cm-1. Kramers-Kronig analysis was used to determine the spectral dependence of the ab and the c components of the dielectric tensor. The optical properties are strongly anisotropic. The ab-plane response resembles that of other reduced-T(c) materials whereas the c axis, in contrast, shows only the presence of several phonons. There is a complete absence of charge carrier response along c above and below T(c). This observation allows us to set an upper limit to the free-carrier spectral weight for transport perpendicular to the CuO2 planes
Race and sex differences in dropout from the STRRIDE trials
Purpose: To determine if race and sex differences exist in determinants and timing of dropout among individuals enrolled in an exercise and/or caloric restriction intervention. Methods: A total of 947 adults with dyslipidemia (STRRIDE I, STRRIDE AT/RT) or prediabetes (STRRIDE-PD) were randomized to either inactive control or to 1 of 10 exercise interventions, ranging from doses of 8â23 kcal/kg/week, intensities of 50%â75% (Formula presented.) peak, and durations of 6â8 months. Two groups included resistance training, and one included a dietary intervention (7% weight loss goal). Dropout was defined as an individual withdrawn from the study, with the reasons for dropout aggregated into determinant categories. Timing of dropout was defined as the last session attended and aggregated into phases (i.e., ârampâ period to allow gradual adaptation to exercise prescription). Utilizing descriptive statistics, percentages were generated according to categories of determinants and timing of dropout to describe the proportion of individuals who fell within each category. Results: Black men and women were more likely to be lost to follow-up (Black men: 31.3% and Black women: 19.6%), or dropout due to work responsibilities (15.6% and 12.5%), âchange of mindâ (12.5% and 8.9%), transportation issues (6.3% and 3.6%), or reported lack of motivation (6.3% and 3.6%). Women in general noted lack of time more often than men as a reason for dropout (White women: 22.4% and Black women: 22.1%). Regardless of race and sex, most participants dropped out during the ramp period of the exercise intervention; with Black women (50%) and White men (37.1%) having the highest dropout rate during this period. Conclusion: These findings emphasize the importance of targeted retention strategies when aiming to address race and sex differences that exist in determinants and timing of dropout among individuals enrolled in an exercise and/or caloric restriction intervention
Spin Susceptibility and Superexchange Interaction in the Antiferromagnet CuO
Evidence for the quasi one-dimensional (1D) antiferromagnetism of CuO is
presented in a framework of Heisenberg model. We have obtained an experimental
absolute value of the paramagnetic spin susceptibility of CuO by subtracting
the orbital susceptibility separately from the total susceptibility through the
Cu NMR shift measurement, and compared directly with the theoretical
predictions. The result is best described by a 1D antiferromagnetic
Heisenberg (AFH) model, supporting the speculation invoked by earlier authors.
We also present a semi-quantitative reason why CuO, seemingly of 3D structure,
is unexpectedly a quasi 1D antiferromagnet.Comment: 7 pages including 4 tables and 9 figure
Quenched charmonium spectrum
We study charmonium using the standard relativistic formalism in the quenched
approximation, on a set of lattices with isotropic lattice spacings ranging
from 0.1 to 0.04 fm. We concentrate on the calculation of the hyperfine
splitting between eta_c and J/psi, aiming for a controlled continuum
extrapolation of this quantity. The splitting extracted from the
non-perturbatively improved clover Dirac operator shows very little dependence
on the lattice spacing for fm. The dependence is much stronger for
Wilson and tree-level improved clover operators, but they still yield
consistent extrapolations if sufficiently fine lattices, fm (), are used. Our result for the hyperfine splitting is
77(2)(6) MeV (where Sommer's parameter, r_0, is used to fix the scale). This
value remains about 30% below experiment. Dynamical fermions and OZI-forbidden
diagrams both contribute to the remainder. Results for the eta_c and J/psi wave
functions are also presented.Comment: 22 pages, 7 figure
A minimal quasiparticle approach for the QGP and its large- limits
We propose a quasiparticle approach allowing to compute the equation of state
of a generic gauge theory with gauge group SU() and quarks in an arbitrary
representation. Our formalism relies on the thermal quasiparticle masses
(quarks and gluons) computed from Hard-Thermal-Loop techniques, in which the
standard two-loop running coupling constant is used. Our model is minimal in
the sense that we do not allow any extra ansatz concerning the
temperature-dependence of the running coupling. We first show that it is able
to reproduce the most recent equations of state computed on the lattice for
temperatures higher than 2 . In this range of temperatures, an ideal gas
framework is indeed expected to be relevant. Then we study the accuracy of
various inequivalent large- limits concerning the description of the QCD
results, as well as the equivalence between the QCD limit and the SUSY Yang-Mills theory. Finally, we estimate the dissociation temperature
of the -meson and comment on the estimations' stability regarding the
different considered large- limits.Comment: 19 pages, 6 figure
ReïŹning and regaining skills in ïŹxation/diversiïŹcation stage performers: The Five-A Model
Technical change is one of many factors underpinning success in elite, fixation/diversification stage performers. Surprisingly, however, there is a dearth of research pertaining to this process or the most efficacious methods used to bring about such a change. In this paper we highlight the emergent processes, yet also the lack in mechanistic comprehension surrounding technical change, addressing issues within the motor control, sport psychology, coaching and choking literature. More importantly, we seek an understanding of how these changes can be made more secure to competitive pressure, and how this can be embedded within the process of technical change. Following this review, we propose The Five-A Model based on successful coaching techniques, psychosocial concomitants, the avoidance of choking and principles of effective behaviour change. Specific mechanisms for each stage are discussed, with a focus on the use of holistic rhythm-based cues as a possible way of internalising changes. Finally, we suggest the need for further research to examine these five stages, to aid a more comprehensive construction of the content and delivery of such a programme within the applied setting
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