The Nature of the Refutation Text Effect: An Investigation of Attention Allocation

Students often hold misconceptions that conflict with scientific explanations. Research has shown that refutation texts are effective for facilitating conceptual change in these cases (Guzzetti, Snyder, Glass, & Gamas, 1993). The process through which refutation texts have their effect is not clear. The authors replicated and extended previous research investigating cognitive processes involved in the refutation text effect. Undergraduates read either a refutation or an expository text on seasonal change. Individual reading times were recorded. Participants’ conceptions were measured at pretest, posttest, and delayed posttest. Results showed that readers spent less time reading the refutation paragraph compared to the expository paragraph. The refutation text group had fewer misconceptions at posttest. These findings suggest that refutation text processing differences mirror similar findings in the attention literature, which may account for their effectiveness

A logic for parametric polymorphism with effects

Abstract. We present a logic for reasoning about parametric polymorphism in combination with arbitrary computational effects (nondeterminism, exceptions, continuations, side-effects etc.). As examples of reasoning in the logic, we show how to verify correctness of polymorphic type encodings in the presence of effects.

Atomic X-ray Spectroscopy of Accreting Black Holes

Current astrophysical research suggests that the most persistently luminous objects in the Universe are powered by the flow of matter through accretion disks onto black holes. Accretion disk systems are observed to emit copious radiation across the electromagnetic spectrum, each energy band providing access to rather distinct regimes of physical conditions and geometric scale. X-ray emission probes the innermost regions of the accretion disk, where relativistic effects prevail. While this has been known for decades, it also has been acknowledged that inferring physical conditions in the relativistic regime from the behavior of the X-ray continuum is problematic and not satisfactorily constraining. With the discovery in the 1990s of iron X-ray lines bearing signatures of relativistic distortion came the hope that such emission would more firmly constrain models of disk accretion near black holes, as well as provide observational criteria by which to test general relativity in the strong field limit. Here we provide an introduction to this phenomenon. While the presentation is intended to be primarily tutorial in nature, we aim also to acquaint the reader with trends in current research. To achieve these ends, we present the basic applications of general relativity that pertain to X-ray spectroscopic observations of black hole accretion disk systems, focusing on the Schwarzschild and Kerr solutions to the Einstein field equations. To this we add treatments of the fundamental concepts associated with the theoretical and modeling aspects of accretion disks, as well as relevant topics from observational and theoretical X-ray spectroscopy.Comment: 63 pages, 21 figures, Einstein Centennial Review Article, Canadian Journal of Physics, in pres

The Intentional Use of Service Recovery Strategies to Influence Consumer Emotion, Cognition and Behaviour

Service recovery strategies have been identified as a critical factor in the success of. service organizations. This study develops a conceptual frame work to investigate how specific service recovery strategies influence the emotional, cognitive and negative behavioural responses of . consumers., as well as how emotion and cognition influence negative behavior. Understanding the impact of specific service recovery strategies will allow service providers' to more deliberately and intentionally engage in strategies that result in positive organizational outcomes. This study was conducted using a 2 x 2 between-subjects quasi-experimental design. The results suggest that service recovery has a significant impact on emotion, cognition and negative behavior. Similarly, satisfaction, negative emotion and positive emotion all influence negative behavior but distributive justice has no effect

Incydenty sercowo-naczyniowe u pacjentów stosujących sildenafil - wyniki badania International Men’s Health Study

Wstęp: Celem pracy było oszacowanie częstości występowania poważnych incydentów sercowo-naczyniowych (np. zawał serca, udar) oraz całkowitej śmiertelności wśród mężczyzn z zaburzeniami erekcji otrzymujących sildenafil. Metody: Prospektywnym, obserwacyjnym badaniem kohortowym International Men’s Health Study (IMHS) objęto pacjentów ze zdiagnozowanymi zaburzeniami erekcji oraz wcześniej stosujących sildenafil lub dopiero zaczynających przyjmować ten preparat. Dane wyjściowe oraz z obserwacji odległej dotyczące chorób sercowo-naczyniowych (CVD), czynników ryzyka oraz zaburzeń erekcji uzyskano za pomocą odpowiednich kwestionariuszy. Do osób, które przebyły epizod sercowo-naczyniowy, wysłano kwestionariusze w celu zebrania informacji związanych z ekspozycją na sildenafil/leczeniem zaburzeń erekcji przed incydentem. Wyniki: W analizowanej grupie (n = 3813) odnotowano 35 incydentów sercowo-naczyniowych u 30 chorych. Częstość zgonu z jakiejkolwiek przyczyny, zawału serca oraz udaru wynosiła odpowiednio 0,4; 0,6 i 0,1 na każdych 100 pacjentolat obserwacji. W grupie 6 mężczyzn, którzy zgłosili stosowanie sildenafilu na miesiąc przed incydentem sercowo-naczyniowym, 2 podało jego użycie w czasie 24 godzin poprzedzających zdarzenie. Wnioski: Wyniki badania IMHS potwierdzają wcześniejsze doniesienia o współwystępowaniu zaburzeń erekcji oraz CVD i o podobnych czynnikach ryzyka tych chorób

Stellar structure and compact objects before 1940: Towards relativistic astrophysics

Since the mid-1920s, different strands of research used stars as "physics laboratories" for investigating the nature of matter under extreme densities and pressures, impossible to realize on Earth. To trace this process this paper is following the evolution of the concept of a dense core in stars, which was important both for an understanding of stellar evolution and as a testing ground for the fast-evolving field of nuclear physics. In spite of the divide between physicists and astrophysicists, some key actors working in the cross-fertilized soil of overlapping but different scientific cultures formulated models and tentative theories that gradually evolved into more realistic and structured astrophysical objects. These investigations culminated in the first contact with general relativity in 1939, when J. Robert Oppenheimer and his students George Volkoff and Hartland Snyder systematically applied the theory to the dense core of a collapsing neutron star. This pioneering application of Einstein's theory to an astrophysical compact object can be regarded as a milestone in the path eventually leading to the emergence of relativistic astrophysics in the early 1960s.Comment: 83 pages, 4 figures, submitted to the European Physical Journal

Understanding preventive behaviors among mid-Western African-American men: a pilot qualitative study of prostate screening

http://dx.doi.org/10.1016/j.jomh.2011.03.00

Plankton ecology: The past two decades of progress

This is a selected account of recent developments in plankton ecology. The examples have been chosen for their degree of innovation during the past two decades and for their general ecological importance. They range from plankton autecology over interactions between populations to community ecology. The autecology of plankton is represented by the hydromechanics of plankton (the problem of life in a viscous environment) and by the nutritional ecology of phyto- and zooplankton. Population level studies are represented by competition, herbivory (grazing), and zooplankton responses to predation. Community ecology is represented by the debate about bottom- up vs. top-down control of community organization, by the PEG model of seasonal plankton succession, and by the recent discovery of the microbial food web