Variational solution of the one-dimensional t–J model

A new variational scheme based on a modified Bethe–Peierls method is used to study the ground state properties of the one-dimensional t–J model. Expectation values are evaluated by cutting out a four-site cluster from a correlated Fermi sea, the ground state of which is described by a variational trial wave function. We study a generalized Gutzwiller state where nearest-neighbour hole–hole correlations are controlled variationally. From the electron concentration dependence of the ground state energy, we determine the true thermodynamic boundary where segregation into an electron-rich, and purely hole phase sets in. We also determine the spinodal line and pair susceptibilities. The variational method is applied also to an extended t–J–V model, where V is the coupling constant of the charge interaction term.     

Recuperación dependiente de estados afectivos en una tarea de reconocimiento

Resumen

Estudiamos los efectos de los estados afectivos de adquisición y recuperación en una tarea de reconocimiento. Los estados afectivos se indujeron por sugestiones posthipnóticas y los estímulos fueron fotografías de caras en blanco y negro. Empleamos un diseño factorial 2 (estado de adquisición) x 2 (estado de recuperación) con medidas repetidas. El intervalo entre las fases de adquisición y recuperación fue de 24 horas. El análisis de datos, basado en el modelo no-paramétrico de la teoría de detección de señales, confirma el efecto de dependencia de estados afectivos en una prueba de reconocimiento. Los resultados se discuten en relación a trabajos anteriores que no habían encontrado este efecto en pruebas similares.     

Does role stress predict burnout over time among health care professionals?

Abstract

The main objective of this study is to test the effects over time of three role stress variables (role conflict, role ambiguity and role overload) on the three burnout dimensions (emotional exhaustion, depersonalization and personal accomplishment). Based on theoretical models on burnout and on meta-analytical research, it is hypothesized that the three role stress variables will predict changes over time in emotional exhaustion and depersonalization, but not in personal accomplishment. The results obtained by means of hierarchical regression analysis partially support the hypothesis. The three role stress variables predict emotional exhaustion over time. Role conflict and role overload predict depersonalization over time. Finally, contrary to expectations, role ambiguity predicts personal accomplishment over time.     

An Athenaeum Curiosity: De Morgan's Reviews of Boole and Jevons

In this note we reproduce the book reviews that De Morgan wrote on Boole's and Jevons's first logical works. The most notable property of these documents is the mere fact of their existence and the absence of any reference to them in the specialized literature.     

Event-related brain potentials reflect traces of echoic memory in humans

In sequences of identical auditory stimuli, infrequent deviant stimuli elicit an event-related brain potential component called mismatch negativity (MMN). MMN is presumed to reflect the existence of a memory trace of the frequent stimulus at the moment of presentation of the infrequent stimulus. This hypothesis was tested by applying the recognition-masking paradigm of cognitive psychology. In this paradigm, a masking sound presented shortly before or after a test stimulus diminishes the recognition memory of this stimulus, the more so the shorter the interval between the test and masking stimuli. This interval was varied in the present study. It was found that the MMN amplitude strongly correlated with the subject’s ability to discriminate between frequent and infrequent stimuli. This result strongly suggests that MMN providesa measure for a trace of sensory memory, and further, that with MMN, this memory can be studied without performance-related distortions.     

Being human,more or less

Robert G. Woodhouse Memorial Philosophy Lecture, Rockland Community College of the State University of New York, Tuesday, 1 December 1992.     

The society for community research and action on a path toward conocimiento: From silences and statements to solidarities in action in U.S. community psychology

A first-person narrative essay is presented through a critically reflexive auto-ethnography of a community psychologist's experiences as a member of the Society for Community Research and Action (SCRA) and (as of this writing) co-chair of the Cultural, Ethnic and Racial Affairs council. Through this methodological orientation, an analysis of some of the discourses that circulated within the SCRA listserv in relation to the murder of Mr. George Floyd, and amidst an ensuing pandemic are analyzed and discussed in relation to Anzaldúa's seven stages of conocimiento. The intentions that guide and ground this first-person account are to animate deeper reflection, accountability, and solidarity-in-action, as well as an organizational shift in the culture of the SCRA. Guided by a set of questions—What accounts for the organizational silences within the SCRA? How did the SCRA respond or engage with the murder of Mr. Floyd, anti-Blackness, Black Lives Matter, and related racial justice efforts?—the purpose is to turn a critical social analysis gaze to the SCRA in order to align its purpose, values, and mission with liberation and a decolonial feminist praxis. Anzaldúa's seven-stage framework of conocimiento is utilized to describe the possibilities for an organizational cultural shift in the SCRA that aligns with racial justice and liberatory decolonial feminist praxes.     

Response selection on the Rorschach Test

After discussion of some theoretical speculations concerning the nature of the Rorschach process, two experimental manipulations of the Rorschach task are presented. Three groups of normal (n = 6) and schizophrenic subjects (7 paranoid and 7 nonparanoid) participated. Their mean age was 30.7 yr. In the first experimental version of the Rorschach, simplified inkblots (sections of the standard cards) were used to verify the influence of stimulus complexity on response for the three groups. In the second, an experimental version of the Rorschach task was created to highlight the influence of the selection process among different associations to blots. To this end, a list including responses both of positive and negative form quality to each card, was provided each subject. Data are discussed, highlighting the minimal differences obtained by the experimental manipulations and relating these to theoretical speculations.     

Moral duty or moral defence? The effects of perceiving shared humanity with the victims of ingroup perpetrated harm

Previous theory and research suggests that perceiving shared humanity with others should be a positive force for intergroup relations. The present research considers the alternative possibility, that notions of shared humanity might protect people from feelings of guilt over ingroup perpetrated harm by obscuring the ingroup's unique role in these events. Consistent with this idea, Study 1 (N = 58) found that perceiving shared humanity with a harmed outgroup was associated with less guilt and stronger expectations of forgiveness among members of the perpetrator group. Study 2 (N = 52) demonstrated that these effects only occurred when the moral integrity of the ingroup was open to question. When ingroup morality was instead secure, defensive use of humanity was not apparent. Together, these studies suggest that perceiving harmful ingroup actions as ‘only human’ can sometimes be a moral defence that absolves group members of feelings of responsibility for wrongdoing. Copyright © 2010 John Wiley & Sons, Ltd.     

The Protestant Ethic in Hungary

While in the 16–17th centuries about two thirds of Hungarians belonged to the Reformed Church, the presence of the ‘spirit of capitalism’ and the ‘Protestant ethic’ is rather questionable. The Calvinists did not play a different or decisive role in the capitalization process of Hungary at the end of the 19th century. This study is a summary of a much longer analysis of the ‘Hungarian Protestant ethic’ of the 17th century. The historical analysis focuses on the Puritan doctrines which can be found in conduct-books as well as the practical religiosity of Hungarian Puritans and Reformed people in that age. The ‘Hungarian Protestant ethic’ differs from Weber's ideal-type in two respects: the Hungarian version is more pietistic, less activist; and it seems to have less practical influence in everyday life because of weak religiosity. The Hungarian case does not refute Weber's thesis, but it does call attention to two important parts of historical analysis: the reinterpreting, selecting procedure in social context, and the intensity of religiosity.