bluuebunny/crossref_metadata_2025 huggingface dataset:
A study of verbal and nonverbal communication in Second Life – the ARCHI21 experience
Authors: Wigham Ciara R. , Chanier Thierry
Published: February 2013

Three-dimensional synthetic worlds introduce possibilities for nonverbal communication in computer-mediated language learning. This paper presents an original methodological framework for the study of multimodal communication in such worlds. It offers a classification of verbal and nonverbal communication acts in the synthetic worldSecond Lifeand outlines relationships between the different types of acts that are built into the environment. The paper highlights some of the differences between the synthetic world's communication modes and those of face-to-face communication and exemplifies the interest of these for communication within a pedagogical context.

We report on the application of the methodological framework to a course inSecond Lifewhich formed part of the European project ARCHI21. This course, for Architecture students, adopted a Content and Learning Integrated Learning approach (CLIL). The languages studied were French and English. A collaborative building activity in the students’ L2 is considered, using a method designed to organise the data collected in screen recordings and to code and transcribe the multimodal acts. We explore whether nonverbal communication acts are autonomous inSecond Lifeor whether interaction between synchronous verbal and nonverbal communication exists. Our study describes how the distribution of the verbal and nonverbal modes varied depending on the pre-defined role the student undertook during the activity. We also describe the use of nonverbal communication to overcome verbal miscommunication where direction and orientation were concerned. In addition, we illustrate how nonverbal acts were used to secure the context for deictic references to objects made in the verbal mode. Finally, we discuss the importance of nonverbal and verbal communication modes in the proxemic organisation of students and the impact of proxemic organisation on the quantity of students’ verbal production and the topics discussed in this mode.

This paper seeks to contribute to some of the methodological reflections needed to better understand the affordances of synthetic worlds, including the verbal and nonverbal communication opportunitiesSecond Lifeoffers, how students use these and their impact on the interaction concerning the task given to students.
The Endogenous Regenerative Capacity of the Damaged Newborn Brain: Boosting Neurogenesis with Mesenchymal Stem Cell Treatment
Authors: Donega Vanessa , van Velthoven Cindy TJ , Nijboer Cora H , Kavelaars Annemieke , Heijnen Cobi J
Published: February 2013

Neurogenesis continues throughout adulthood. The neurogenic capacity of the brain increases after injury by, e.g., hypoxia–ischemia. However, it is well known that in many cases brain damage does not resolve spontaneously, indicating that the endogenous regenerative capacity of the brain is insufficient. Neonatal encephalopathy leads to high mortality rates and long-term neurologic deficits in babies worldwide. Therefore, there is an urgent need to develop more efficient therapeutic strategies. The latest findings indicate that stem cells represent a novel therapeutic possibility to improve outcome in models of neonatal encephalopathy. Transplanted stem cells secrete factors that stimulate and maintain neurogenesis, thereby increasing cell proliferation, neuronal differentiation, and functional integration. Understanding the molecular and cellular mechanisms underlying neurogenesis after an insult is crucial for developing tools to enhance the neurogenic capacity of the brain. The aim of this review is to discuss the endogenous capacity of the neonatal brain to regenerate after a cerebral ischemic insult. We present an overview of the molecular and cellular mechanisms underlying endogenous regenerative processes during development as well as after a cerebral ischemic insult. Furthermore, we will consider the potential to use stem cell transplantation as a means to boost endogenous neurogenesis and restore brain function.
A macroscopic model of proton transport through the membrane-ionomer interface of a polymer electrolyte membrane fuel cell
Authors: Kumar Milan , Edwards Brian J. , Paddison Stephen J.
Published: February 2013

The membrane-ionomer interface is the critical interlink of the electrodes and catalyst to the polymer electrolyte membrane (PEM); together forming the membrane electrode assembly in current state-of-the-art PEM fuel cells. In this paper, proton conduction through the interface is investigated to understand its effect on the performance of a PEM fuel cell. The water containing domains at this interface were modeled as cylindrical pores/channels with the anionic groups (i.e., –SO3−) assumed to be fixed on the pore wall. The interactions of each species with all other species and an applied external field were examined. Molecular-based interaction potential energies were computed in a small test element of the pore and were scaled up in terms of macroscopic variables. Evolution equations of the density and momentum of the species (water molecules and hydronium ions) were derived within a framework of nonequilibrium thermodynamics. The resulting evolution equations for the species were solved analytically using an order-of-magnitude analysis to obtain an expression for the proton conductivity. Results show that the conductivity increases with increasing water content and pore radius, and strongly depends on the separation distance between the sulfonate groups and their distribution on the pore wall. It was also determined that the conductivity of two similar pores of different radii in series is limited by the pore with the smaller radius.
An efficient method for calculating dynamical hyperpolarizabilities using real-time time-dependent density functional theory
Authors: Ding Feizhi , Van Kuiken Benjamin E. , Eichinger Bruce E. , Li Xiaosong
Published: February 2013

In this paper we present a time-domain time-dependent density functional theory (TDDFT) approach to calculate frequency-dependent polarizability and hyperpolarizabilities. In this approach, the electronic degrees of freedom are propagated within the density matrix based TDDFT framework using the efficient modified midpoint and unitary transformation algorithm. We use monochromatic waves as external perturbations and apply the finite field method to extract various orders of the time-dependent dipole moment. By fitting each order of time-dependent dipole to sinusoidal waves with harmonic frequencies, one can obtain the corresponding (hyper)polarizability tensors. This approach avoids explicit Fourier transform and therefore does not require long simulation time. The method is illustrated with application to the optically active organic molecule para-nitroaniline, of which the frequency-dependent polarizability α(−ω; ω), second-harmonic generation β(−2ω; ω, ω), optical rectification β(0; −ω, ω), third-harmonic generation γ(−3ω; ω, ω, ω), and degenerate four-wave mixing γ(−ω; ω, ω, −ω) are calculated.
A multireference perturbation study of the NN stretching frequency of trans-azobenzene in nπ* excitation and an implication for the photoisomerization mechanism
Authors: Harabuchi Yu , Ishii Moe , Nakayama Akira , Noro Takeshi , Taketsugu Tetsuya
Published: February 2013

A multireference second-order perturbation theory is applied to calculate equilibrium structures and vibrational frequencies of trans-azobenzene in the ground and nπ* excited states, as well as the reaction pathways for rotation and inversion mechanism in the nπ* excited state. It is found that the NN stretching frequency exhibits a slight increase at the minimum energy structure in the nπ* state, which is explained by the mixing of the NN stretching mode with the CN symmetric stretching mode. We also calculate the NN stretching frequency at several selected structures along the rotation and inversion pathways in the nπ* state, and show that the frequency decreases gradually along the rotation pathway while it increases by ca. 300 cm−1 along the inversion pathway. The frequencies and energy variations along the respective pathways indicate that the rotation pathway is more consistent with the experimental observation of the NN stretching frequency in nπ* excitation.
Atomic rearrangements in amorphous Al2O3 under electron-beam irradiation
Authors: Nakamura R. , Ishimaru M. , Yasuda H. , Nakajima H.
Published: February 2013

The electron-irradiation-induced crystallization of amorphous Al2O3 (a-Al2O3) was investigated by in-situ transmission electron microscopy under the wide electron-energy region of 25–300 keV. The formation of γ-Al2O3 nanocrystallites was induced by irradiating the a-Al2O3 thin film along with the formation of nanovoids in the crystalline grains regardless of the acceleration voltage. The crystallization became more pronounced with decreasing the electron energy, indicating that electronic excitation processes play a dominant role in the formation of γ-Al2O3. Radial distribution analyses suggested that a-Al2O3 transforms to γ-phase via the “excited” (“stimulated”) amorphous state, in which the breaking and rearrangement of unstable short-range Al-O bonds, i.e., fivefold-coordinated Al-O (AlO5) basic units, occur.
Structural characterization of superlattice of microcrystalline silicon carbide layers for photovoltaic application
Authors: Chaudhuri Partha , Kole Arindam , Haider Golam
Published: February 2013

We have systematically studied a series of silicon carbide multilayer (#SiC) samples, each consisting of 30 periods of two alternating layers of microcrystalline silicon carbide (μc-SiC:H) having identical band gap of 2.2 eV but different amount of crystalline silicon volume fraction. The thickness of the μc-SiC:H layer deposited at higher power (termed as HPL) with higher degree of crystallinity was kept fixed at a value of 5 nm, while the thickness of the other μc-SiC:H layer deposited at a lower power (termed as LPL) was changed from 13 nm to 2 nm for the different samples of the series. With lowering of the LPL thickness, a decrease in the void fraction together with an improvement in the short range order within the multilayered samples was observed. By decreasing the thickness of the LPL layer up to 2 nm, the photoluminescence study indicates the formation of an intermediate band within the superlattice of μc-SiC:H. Photovoltaic properties of this superlattice layer were investigated in a p-i-n diode structure.
A dual-polarized broadband planar antenna and channelizing filter bank for millimeter wavelengths
Authors: O'Brient Roger , Ade Peter , Arnold Kam , Edwards Jennifer , Engargiola Greg , Holzapfel William L. , Lee Adrian T. , Myers Michael J. , Quealy Erin , Rebeiz Gabriel , Richards Paul , Suzuki Aritoki
Published: February 2013

We describe the design, fabrication, and testing of a broadband log-periodic antenna coupled to multiple cryogenic bolometers. This detector architecture, optimized here for astrophysical observations, simultaneously receives two linear polarizations with two octaves of bandwidth at millimeter wavelengths. The broad bandwidth signal received by the antenna is divided into sub-bands with integrated in-line frequency-selective filters. We demonstrate two such filter banks: a diplexer with two sub-bands and a log-periodic channelizer with seven contiguous sub-bands. These detectors have receiver efficiencies of 20%–40% and percent level polarization isolation. Superconducting transition-edge sensor bolometers detect the power in each sub-band and polarization. We demonstrate circularly symmetric beam patterns, high polarization isolation, accurately positioned bands, and high optical efficiency. The pixel design is applicable to astronomical observations of intensity and polarization at millimeter through sub-millimeter wavelengths. As compared with an imaging array of pixels measuring only one band, simultaneous measurements of multiple bands in each pixel has the potential to result in a higher signal-to-noise measurement while also providing spectral information. This development facilitates compact systems with high mapping speeds for observations that require information in multiple frequency bands.
Thermodynamic stabilization of nanocrystalline binary alloys
Authors: Saber Mostafa , Kotan Hasan , Koch Carl C. , Scattergood Ronald O.
Published: February 2013

The work presented here was motivated by the need to develop a predictive model for thermodynamic stabilization of binary alloys that is applicable to strongly segregating size-misfit solutes, and that can use available input data for a wide range of solvent-solute combinations. This will serve as a benchmark for selecting solutes and assessing the possible contribution of thermodynamic stabilization for development of high-temperature nanocrystalline alloys. Following a regular solution model that distinguishes the grain boundary and grain interior volume fractions by a transitional interface in a closed system, we include both the chemical and elastic strain energy contributions to the mixing enthalpy ΔHmix using an appropriately scaled linear superposition. The total Gibbs mixing free energy ΔGmix is minimized with respect to simultaneous variations in the grain-boundary volume fraction and the solute contents in the grain boundary and grain interior. The Lagrange multiplier method was used to obtain numerical solutions with the constraint of fixed total solute content. The model predictions are presented using a parametric variation of the required input parameters. Applications are then given for the dependence of the nanocrystalline grain size on temperature and total solute content for selected binary systems where experimental results suggest that thermodynamic stabilization could be effective.
Uniaxial anisotropy of two-magnon scattering in an ultrathin epitaxial Fe layer on GaAs
Authors: Kurebayashi H. , Skinner T. D. , Khazen K. , Olejník K. , Fang D. , Ciccarelli C. , Campion R. P. , Gallagher B. L. , Fleet L. , Hirohata A. , Ferguson A. J.
Published: February 2013

We report an on-chip, electrically detected ferromagnetic resonance study on microbars made from GaAs/Fe(1 nm)/GaAs layers. Our experiments, performed at several different microwave frequencies and static magnetic field directions, enable us to observe a strong in-plane uniaxial anisotropy of the linewidth. We attribute the linewidth anisotropy to the two magnon scattering process, supporting this by calculations of possible linewidth broadening mechanisms. Our findings are useful for designing future high-performance spintronic devices based on nanoscale magnetic structures.
Improvement of volume holographic performance by plasmon-induced holographic absorption grating
Authors: Li Chengmingyue , Cao Liangcai , Li Jingming , He Qingsheng , Jin Guofan , Zhang Shiman , Zhang Fushi
Published: February 2013

We report on the enhanced holographic performance by employing a strong volume holographic absorption grating induced by localized surface plasmon resonance effect in a bulk gold nanoparticles doped photopolymer. The contributions of plasmon-induced volume holographic absorption grating is characterized through the Kogelnik's coupled wave model and demonstrated experimentally by using two-beam interference technology. At the 0.05 vol. % concentration of the gold nanoparticles in the bulk photopolymer, 101.8% increase in the diffraction efficiency and more than four times suppression of the first side lobe in angular selectivity have been achieved.
Probing nanowire edge roughness using an extended magnetic domain wall
Authors: O'Shea K. J. , Tracey J. , Bramsiepe S. , Stamps R. L.
Published: February 2013

Using Lorentz transmission electron microscopy, a unique experiment is realised in which an extended magnetic domain wall in a ferromagnetic nanowire, strongly pinned at one end, is utilised as a local probe of the distribution of pinning sites along the nanowire edges. Fresnel imaging is used to examine the detailed de-pinning process and extract a distribution of pinning energies along the wire. The pinning sites were found to be randomly distributed with surprisingly little correlation between pinning site location and visible structural features along the wire edge.
Multilevel resistive switching memory with amorphous InGaZnO-based thin film
Authors: Hsu Ching-Hui , Fan Yang-Shun , Liu Po-Tsun
Published: February 2013

Multi-level storage capability of resistive random access memory (RRAM) using amorphous indium-gallium-zinc-oxide (InGaZnO) thin film is demonstrated by the TiN/Ti/InGaZnO/Pt device structure under different operation modes. The distinct four-level resistance states can be obtained by varying either the trigger voltage pulse or the compliance current. In addition, the RRAM devices exhibit superior characteristics of programming/erasing endurance and data retention for the application of multi-level nonvolatile memory technology. Physical transport mechanisms for the multi-level resistive switching characteristics are also deduced in this study.
Integrated sensor for ultra-thin layer sensing based on hybrid coupler with short-range surface plasmon polariton and dielectric waveguide
Authors: Fan Boyu , Liu Fang , Wang Xiaoyan , Li Yunxiang , Cui Kaiyu , Feng Xue , Huang Yidong
Published: February 2013

Based on a hybrid coupler composed of short-range surface plasmon polariton (SRSPP) and dielectric waveguides, an integrated sensor for ultra-thin layer sensing has been realized. The simulation and experiment results demonstrate that the thickness variation of detection layer (polymer layer) about several nanometers could be detected. The measured thickness-detection sensitivity is as high as 0.67 dB/nm. And the sensitive region for thickness variation of polymer layer can be adjusted widely by varying the thickness of the SRSPP waveguide.
Effect of antimony nano-scale surface-structures on a GaSb/AlAsSb distributed Bragg reflector
Authors: Husaini S. , Shima D. , Ahirwar P. , Rotter T. J. , Hains C. P. , Dang T. , Bedford R. G. , Balakrishnan G.
Published: February 2013

Effects of antimony crystallization on the surface of GaSb during low temperature molecular beam epitaxy growth are investigated. The geometry of these structures is studied via transmission electron and atomic force microscopies, which show the surface metal forms triangular-shaped, elongated nano-wires with a structured orientation composed entirely of crystalline antimony. By depositing antimony on a GaSb/AlAsSb distributed Bragg reflector, the field is localized within the antimony layer. Polarization dependent transmission measurements are carried out on these nano-structures deposited on a GaSb/AlAsSb distributed Bragg reflector. It is shown that the antimony-based structures at the surface favor transmission of light polarized perpendicular to the wires.
Improvement of heat transfer efficiency at solid-gas interfaces by self-assembled monolayers
Authors: Liang Zhi , Evans William , Desai Tapan , Keblinski Pawel
Published: February 2013

Using molecular dynamics simulations, we demonstrate that the efficiency of heat exchange between a solid and a gas can be maximized by functionalizing solid surface with organic self-assembled monolayers (SAMs). We observe that for bare metal surfaces, the thermal accommodation coefficient (TAC) strongly depends on the solid-gas interaction strength. For metal surfaces modified with organic SAMs, the TAC is close to its theoretical maximum and is essentially independent from the SAM-gas interaction strength. The analysis of the simulation results indicates that softer and lighter SAMs, compared to the bare metal surfaces, are responsible for the greatly enhanced TAC.
Rules that govern UPF1 binding to mRNA 3′ UTRs
Authors: Kurosaki Tatsuaki , Maquat Lynne E.
Published: February 2013

Nonsense-mediated mRNA decay (NMD), which degrades transcripts harboring a premature termination codon (PTC), depends on the helicase up-frameshift 1 (UPF1). However, mRNAs that are not NMD targets also bind UPF1. What governs the timing, position, and function of UPF1 binding to mRNAs remains unclear. We provide evidence that (
i
) multiple UPF1 molecules accumulate on the 3′-untranslated region (3′ UTR) of PTC-containing mRNAs and to an extent that is greater per unit 3′ UTR length if the mRNA is an NMD target; (
ii
) UPF1 binding begins ≥35 nt downstream of the PTC; (
iii
) enhanced UPF1 binding to the 3′ UTR of PTC-containing mRNA relative to its PTC-free counterpart depends on translation; and (
iv
) the presence of a 3′ UTR exon–junction complex (EJC) further enhances UPF1 binding and/or affinity. Our data suggest that NMD involves UPF1 binding along a 3′ UTR whether the 3′ UTR contains an EJC. This binding explains how mRNAs without a 3′ UTR EJC but with an abnormally long 3′ UTR can be NMD targets, albeit not as efficiently as their counterparts that contain a 3′ UTR EJC.
Contrasting effects on path integration after hippocampal damage in humans and rats
Authors: Kim Soyun , Sapiurka Maya , Clark Robert E. , Squire Larry R.
Published: February 2013

The hippocampus and other medial temporal lobe structures have been linked to both memory and spatial cognition, but it has been unclear how these ideas are connected. We carried out parallel studies of path integration in patients with medial temporal lobe lesions and rats with hippocampal lesions. Subjects entered a circular arena without vision, searched for a target, and then attempted to return to the start location. Patients performed accurately, and as well as controls, so long as the outward path was relatively direct and the target was found within 20 s. In sharp contrast, rats with hippocampal lesions were impaired, even when the outward path was shorter than 1 m, involved no turns, and the target was found within 3 s. We suggest that patients succeeded because performance could be supported by working memory and that patients and rats differ after hippocampal lesions in their ability to construct a coherent working memory of spatial environments.
Electronic Health Record–Based Detection of Risk Factors for Clostridium difficile Infection Relapse
Authors: Hebert Courtney , Du Hongyan , Peterson Lance R. , Robicsek Ari
Published: February 2013

Objective.

A major challenge in treating Clostridium difficile infection (CDI) is relapse. Many new therapies are being developed to help prevent this outcome. We sought to establish risk factors for relapse and determine whether fields available in an electronic health record (EHR) could be used to identify high-risk patients for targeted relapse prevention strategies.

Design.

Retrospective cohort study.

Setting.

Large clinical data warehouse at a 4-hospital healthcare organization.

Participants.

Data were gathered from January 2006 through October 2010. Subjects were all inpatient episodes of a positive C. difficile test where patients were available for 56 days of follow-up.

Methods.

Relapse was defined as another positive test between 15 and 56 days after the initial test. Multivariable regression was performed to identify factors independently associated with CDI relapse.

Results.

Eight hundred twenty-nine episodes met eligibility criteria, and 198 resulted in relapse (23.9%). In the final multivariable analysis, risk of relapse was associated with age (odds ratio [OR], 1.02 per year [95% confidence interval (CI), 1.01–1.03]), fluoroquinolone exposure in the 90 days before diagnosis (OR, 1.58 [95% CI, 1.11–2.26]), intensive care unit stay in the 30 days before diagnosis (OR, 0.47 [95% CI, 0.30–0.75]), cephalosporin (OR, 1.80 [95% CI, 1.19–2.71]), proton pump inhibitor (PPI; OR, 1.55 [95% CI, 1.05–2.29]), and metronidazole exposure after diagnosis (OR, 2.74 [95% CI, 1.64–4.60]). A prediction model tuned to ensure a 50% probability of relapse would flag 14.6% of CDI episodes.

Conclusions.

Data from a comprehensive EHR can be used to identify patients at high risk for CDI relapse. Major risk factors include antibiotic and PPI exposure.
Escherichia coliSequence Type 131 Is a Dominant, Antimicrobial-Resistant Clonal Group Associated with Healthcare and Elderly Hosts
Authors: Banerjee Ritu , Johnston Brian , Lohse Christine , Porter Stephen B. , Clabots Connie , Johnson James R.
Published: February 2013

Objective.

To determine prevalence, predictors, and outcomes of infection due toEscherichia colisequence type ST131.

Design.

Retrospective cohort.

Setting.

All healthcare settings in Olmsted County, Minnesota (eg, community hospital, tertiary care center, long-term care facilities, and ambulatory clinics).

Patients.

Ambulatory and hospitalized children and adults with extraintestinalE. coliisolates.

Methods.

We analyzed 299 consecutive, nonduplicate extraintestinalE. coliisolates submitted to Olmsted County laboratories in February and March 2011. ST131 was identified using single-nucleotide polymorphism polymerase chain reaction and further evaluated through pulsed-field gel electrophoresis. Associated clinical data were abstracted through medical record review.

Results.

Most isolates were from urine specimens (90%), outpatients (68%), and community-associated infections (61%). ST131 accounted for 27% of isolates overall and for a larger proportion of those isolates resistant to fluoroquinolones (81%), trimethoprim-sulfamethoxazole (42%), gentamicin (79%), and ceftriaxone (50%). The prevalence of ST131 increased with age (accounting for 5% of isolates from those 11–20 years of age, 26% of isolates from those 51–60 years of age, and 50% of isolates from those 91–100 years of age). ST131 accounted for a greater proportion of healthcare-associated isolates (49%) than community-associated isolates (15%) and for fully 76% ofE. coliisolates from long-term care facility (LTCF) residents. Multivariable predictors of ST131 carriage included older age, LTCF residence, previous urinary tract infection, high-complexity infection, and previous use of fluoroquinolones, macrolides, and extended-spectrum cephalosporins. With multivariable adjustment, ST131-associated infection outcomes included receipt of more than 1 antibiotic (odds ratio [OR], 2.54 [95% confidence interval (CI), 1.25–5.17]) and persistent or recurrent symptoms (OR, 2.53 [95% CI, 1.08–5.96]). Two globally predominant ST131 pulsotypes accounted for 45% of STB 1 isolates.

Conclusions.

ST131isa dominant, antimicrobial-resistant clonal group associated with healthcare settings, elderly hosts, and persistent or recurrent symptoms.
Compare and contrast the reaction coordinate diagrams for chemical reactions and cytoskeletal force generators
Authors: Scholey Jonathan M.
Published: February 2013

Reaction coordinate diagrams are used to relate the free energy changes that occur during the progress of chemical processes to the rate and equilibrium constants of the process. Here I briefly review the application of these diagrams to the thermodynamics and kinetics of the generation of force and motion by cytoskeletal motors and polymer ratchets as they mediate intracellular transport, organelle dynamics, cell locomotion, and cell division. To provide a familiar biochemical context for discussing these subcellular force generators, I first review the application of reaction coordinate diagrams to the mechanisms of simple chemical and enzyme-catalyzed reactions. My description of reaction coordinate diagrams of motors and polymer ratchets is simplified relative to the rigorous biophysical treatment found in many of the references that I use and cite, but I hope that the essay provides a valuable qualitative representation of the physical chemical parameters that underlie the generation of force and motility at molecular scales. In any case, I have found that this approach represents a useful interdisciplinary framework for understanding, researching, and teaching the basic molecular mechanisms by which motors contribute to fundamental cell biological processes.
He II optical depth and ultraviolet escape fraction of galaxies
Authors: Khaire Vikram , Srianand Raghunathan
Published: February 2013

We study the effect that H i ionizing photons escaping from high-redshift (high-z) galaxies have on the He ii ionizing ultraviolet background (UVB) radiation. While these photons do not directly interact with He ii ions, we show that they play an important role, through radiative transport, in modifying the shape of the He ii ionizing part of the UVB spectrum. Within the observed range of UV escape from galaxies, we show that the rapid increase in the He ii Lyα effective optical depth at z ∼ 2.7 can naturally be explained by radiative transport effects. Therefore, the relationship between a well-measured He ii Lyα effective optical depth and the redshift in the post-He ii reionization era can be used to place additional constraints on the redshift evolution of UV escape from high-z galaxies. Our study also suggests that the escape fraction of H i ionizing photons from galaxies has an important role in the fluctuations of the He ii ionizing UVB.
Introduction
Authors: Mele Alfred R. , Rawling Piers
Published: February 2013

This article examines the nature of rationality. The domain of rationality is customarily divided into the theoretical and the practical. Whereas theoretical or epistemic rationality is concerned with what it is rational to believe, and sometimes with rational degrees of belief, practical rationality is concerned with what it is rational to do, or intend or desire to do. This article raises some of the main issues relevant to philosophical discussion of the nature of rationality. Discussions of the nature of practical rationality and reason concern norms of choice, and it seems that if such norms are not arbitrary, arguments over what those norms are must ultimately be a theoretical matter. Furthermore, this article explores rationality's role in and relation to other domains of inquiry: psychology, gender, personhood, language, science, economics, law, and evolution.
The Historiography of Early Modern Brazil
Authors: Schwartz Stuart B.
Published: February 2013

Scholarship on the early modern era in Brazil has been booming since the 1980s. This trend has been influenced theoretically by developments in the social sciences and by the cultural turn in history, by new information technologies of digitalization and the Internet, and by a series of centenaries that have generated institutional support for publications, conferences, and research. This article identifies a number of major themes and questions that have organized much of this historical production, notes the major writings that have moved the field in new directions, and discusses the shifts in emphasis in historical inquiry by concentrating on some of the works that have been seminal in the study of colonial Brazil. Five themes or trends are highlighted: the social history of the major groups within the colony (merchants, cane farmers and sugar barons, slaves, and the free population of color); a complementary cultural approach that has added attention to issues such as private life, public rituals, and subaltern agency; Afro-Brazilian life and culture; a surprisingly rich literature on the indigenous population; and studies of colonial governance.
Sexuality in Colonial Spanish America
Authors: Lavrin Asunción
Published: February 2013

This article follows some of the works that have tackled the sometimes thorny issue of how to recover and interpret the historical memory of sexual behavior. Sexuality is defined as the set of activities and forms of behavior directly related to contact between the sexes, as well as the ideas and ideology developed to understand the nature of sexual relations and the mechanisms devised to control it. That ideology was mostly formulated by religious authorities and enforced by the state through institutions such as the Inquisition and the ecclesiastical and civil courts. What seems to be lacking in the current historiography is the extension of some concepts based on human sexuality to larger arenas of human relations and governance, such as the analysis of medical views on sex and its effects on the development of health policies, the influence of religious discourse on sex and on legislation affecting the social order, the sexual content of religious discourse, the erotic content of religious writings, and the hidden sexual meanings of political discourse.
Latin American Labor History
Authors: Brennan James P.
Published: February 2013

Latin America has a long urban tradition. Since the middle of the nineteenth century, it has been more urbanized than any other region on the globe except North America, northwestern Europe, and Australia/New Zealand. This has produced large urban working classes, large labor movements, and an equally large—and by now traditional—labor historiography, particularly in Latin America itself. This article discusses trends that have shifted the focus from organized labor to workers themselves and their sociocultural world inside and outside the factory. It covers working-class formation during the second half of the nineteenth century, the influence of anarchism and socialism on labor and urban life from the 1880s to the Great Depression, the relationship of organized labor and populist regimes from the latter event to the 1960s, and the emergence since then of what has been called “new unionism,” a more politically independent and grass-roots form of labor mobilization.
Disease, Medicine, and Health
Authors: Armus Diego , Denis Adrián López
Published: February 2013

This article focuses on three overlapping trends in the historical study of human responses to illness, labeled as “new history of medicine, history of public health, and sociocultural history of disease.” The topics range from colonial epidemiology and pharmacopoeia to twentieth-century public health institutions and urban hygiene. But a consistent focus on the social, cultural, and symbolic components of diseases and cures unifies this historiography and distinguishes it from the narrower scope of the long-established field of the history of medicine.
Positive Emotions
Authors: Cohn Michael A. , Fredrickson Barbara L.
Published: February 2013

Positive emotions include pleasant or desirable situational responses, ranging from interest and contentment to love and joy, but are distinct from pleasurable sensation and undifferentiated positive affect. These emotions are markers of people's overall well-being or happiness, but they also enhance future growth and success. This has been demonstrated in work, school, relationships, mental and physical health, and longevity. The broaden-and-build theory of positive emotions suggests that all positive emotions lead to broadened repertoires of thoughts and actions and that broadening helps build resources that contribute to future success. Unlike negative emotions, which are adapted to provide a rapid response to a focal threat, positive emotions occur in safe or controllable situations and lead more diffusely to seeking new resources or consolidating gains. These resources outlast the temporary emotional state and contribute to later success and survival.

This chapter discusses the nature of positive emotions both as evolutionary adaptations to build resources and as appraisals of a situation as desirable or rich in resources. We discuss the methodological challenges of evoking positive emotions for study both in the lab and in the field and issues in observing both short-term (“broaden”) and long-term (“build”) effects. We then review the evidence that positive emotions broaden perception, attention, motivation, reasoning, and social cognition and ways in which these may be linked to positive emotions' effects on important life outcomes. We also discuss and contextualize evidence that positive emotions may be detrimental at very high levels or in certain situations. We close by discussing ways in which positive emotions theory can be harnessed by both basic and applied positive psychology research.
The Positive Youth Development Perspective: Theoretical and Empirical Bases of a Strengths-Based Approach to Adolescent Development
Authors: Lerner Richard M.
Published: February 2013

This chapter presents the conceptual foundations of the positive youth development (PYD) perspective by reviewing the history of theories about adolescent development and by specifying the key theoretical ideas defining the PYD perspective. By drawing in the main from the findings derived from the first longitudinal study of adolescents designed to test ideas associated with the PYD perspective—the 4-H Study of Positive Youth Development—illustrations are provided of the burgeoning empirical work assessing among diverse adolescents the usefulness of this strengths-based approach to youth. Finally, there is a discussion of the implications of PYD theory and research for future scholarship and applications aimed at improving the life chances of diverse adolescents.
New Territories of Positive Life-Span Development: Wisdom and Life Longings
Authors: Scheibe Susanne , Kunzmann Ute , Baltes Paul B.
Published: February 2013

In search for concepts that help understand how individuals strive for growth and perfection within the boundaries and constraints of human lives, we describe theory and research on the concepts of wisdom, or expert knowledge about human nature and the life course, and Sehnsucht (life longings), the recurring and strong desire for ideal (utopian), alternative states and expressions of life. Both represent relatively new concepts on the agenda of lifespan research, originating from an interest in identifying major topics of public and humanist discourse about the potentials and constraints of life-span development and finding ways to measure them with the methods of normative psychological science. Despite their complexity and multiple meanings, progress has been made in the theory-driven operationalization of wisdom and life longings, allowing new insights into their ontogenesis and role for positive development. Emerging research shows that wisdom and life longings do not directly promote a hedonic life orientation or happiness: neither the insight that life is incomplete (wisdom) nor the experience of this incompleteness (life longings) is compatible with feelings of unequivocal joy and pleasure. Yet, there is emerging evidence that they contribute to other aspects of positive development, emphasizing personal growth, meaning, and the aligning of one's own and other's well-being. We suggest that future research should focus on the links of wisdom and life longings with multiple developmental outcomes and the possible interplay of both concepts in promoting positive development.
The Social Construction of Self-Esteem
Authors: Hewitt John P.
Published: February 2013

Self-esteem is examined here as an object of cultural discourse and as a socially constructed emotion grounded in mood. Scientific and popular conceptions of self-esteem share an emphasis on the person's acceptance by self and others, the evaluation of performance, social comparison, and the efficacy of individual action as the important roots of self-esteem. The present analysis deconstructs these elements, treating them not as psychological universals but rather as deeply rooted in the competing themes of American culture. The discourse of self-esteem translates these themes into personal terms, enabling the person's understanding of where he or she stands in relation to such contradictory emphases as individuality versus community, striving for success versus self-acceptance, or the quest for happiness as a future state versus contentment with one's present lot. The socially constructed, discursive nature of self-esteem does not preclude an examination of its underlying psychological reality, which is here conceived as mood. Self-esteem provides a way of experiencing and interpreting mood, which functions to encourage and inhibit conduct in various situations depending upon the individual's ongoing experiences. Mood is a universal response to positive and negative experiences; self-esteem is a particular construction of mood fitted to a culture and its dominant and competing themes. The analysis considers how self-esteem binds the person to particular cultural emphases and examines the limitations of the contemporary self-esteem movement.
Coping Through Emotional Approach: Emerging Evidence for the Utility of Processing and Expressing Emotions in Responding to Stressors
Authors: Stanton Annette L. , Sullivan Sarah J. , Austenfeld Jennifer L.
Published: February 2013

Emotional approach coping (EAC) is a construct encompassing the intentional use of emotional processing and emotional expression in efforts to manage adverse circumstances. The construct was developed in an attempt to reconcile a discrepancy between the empirical coping literature, in which an association between the use of emotion-focused coping and maladjustment often is reported, and literature in other areas describing the adaptive roles of emotional processing and expression. At least two significant limitations in the way emotion-focused coping has been operationalized help explain this discrepancy: widely disparate coping strategies, both approach-oriented and avoidance-oriented, are designated as emotion-focused coping in the literature, and some emotion-focused coping items in published measures are confounded with expressions of distress or self-deprecation.

To address these problems in measurement, the EAC scale was developed. The measure includes two correlated but distinct subscales: Emotional Processing (i.e., attempts to acknowledge, explore, and understand emotions) and Emotional Expression (i.e., verbal and/or nonverbal efforts to communicate or symbolize emotional experience). Recent research using this psychometrically sound measure has provided evidence that EAC enhances adjustment to stressors including infertility, sexual assault, and breast cancer. The findings are not uniform, however, and further study of moderators such as the interpersonal context, the nature of the stressor, cognitive appraisals of the stressor, and individual differences is needed, along with additional study of mechanisms for the effects of EAC. Although emotional processing and expression are core components of many clinical approaches, specific measurement of EAC thus far has been limited to only a few clinical intervention trials. An understanding of who benefits from EAC in which contexts and how these benefits accrue will require continued integration of findings from stress and coping research, emotion science, and clinical studies.
The Role of Personal Control in Adaptive Functioning
Authors: Thompson Suzanne C.
Published: February 2013

A sense of personal control is an important resource that helps people maintain emotional stability and successfully negotiate their way through life. People foster their perceived control by focusing on reachable goals, creating new avenues for control, and accepting difficult-to-change circumstances. In general, perceived control need not be realistic in order to have beneficial effects, although in the area of health promotion, overestimating one's control can reduce the motivation to engage in protection. Research on ethnic differences in the benefits of a sense of personal control suggests that those from more collectivistic cultures or subcultures may be less benefited by a sense of personal control, relying instead on a socially derived sense of control. Successful interventions to enhance personal control include programs that bolster coping skills, give options and decisions to participants, and provide training that encourages attributions to controllable factors. Future research should further explore ethnic differences in the effects of personal control, the consequences of unrealistic control perceptions, and interventions to enhance the sense of control.
Self-Determination
Authors: Wehmeyer Michael L. , Little Todd D. , Sergeant Julie
Published: February 2013

Self-determination is a general psychological construct within the organizing structure of theories of human agency which refers to self- (vs. other-) caused action—to people acting volitionally, based on their own will. Human agency refers to the sense of personal empowerment involving both knowing and having what it takes to achieve goals. Human agentic theories share the meta-theoretical view that organismic aspirations drive human behaviors. An organismic perspective of self-determination that views people as active contributors to, or “authors” of their behavior, where behavior is self-regulated and goal-directed, provides a compelling foundation for examining and facilitating the degree to which people become self-determined and the impact of that on the pursuit of optimal human functioning and well-being. Further, an organismic approach to self-determination requires an explicit focus on the interface between the self and context. This chapter discusses the self-determination construct within an organismic perspective, surveys the construct's history and usage in philosophy and psychology, and summarizes four overarching theories of self-determination that are applicable to the field of positive psychology, as well as examining a number of complementary views of human agency as a process of self-determination. Finally, research implications based upon existing knowledge and research in self-determination and positive psychology are identified.
Forgiveness
Authors: McCullough Michael E. , Root Lindsey M. , Tabak Benjamin A. , van Oyen Witvliet Charlotte
Published: February 2013

We posit that humans have a propensity to forgive, under certain circumstances, that is every bit as intrinsic to human nature as the tendency to seek revenge when harmed. The human tendency to forgive is reliably elicited by social and environmental factors that lead victims to view their transgressors as worthy of care, potentially valuable to the victim in the future, and safe. The victim's personality characteristics may also influence the likelihood of viewing transgressors as careworthy, valuable, and safe. Using these categories, we review recent developments in the scientific study of the social and personality factors that promote forgiveness. We also review developments in the measurement of forgiveness, the links of forgiveness to health and well-being, and quantitative evidence regarding the effectiveness of interventions for promoting forgiveness.
Love
Authors: Hendrick Clyde , Hendrick Susan S.
Published: February 2013

The development of relationship science is integral to the development of positive psychology. The scientific study of love is of central importance to relationship science and is, therefore, very important for positive psychology. This chapter focuses primarily on the history and science of romantic love. One historical view is that romantic love, and especially “love marriage,” developed only in the past few centuries. Other scholars (e.g., Hatfield) have argued that passionate love is a human universal, existing across time and cultures. So this issue is open. The study of love divides into naturalistic/biological approaches (such as passionate vs. companionate love, attachment, and the evolution of love) and psychological/social approaches. The latter include prototypes of love, self-expansion theory, triangular theory, and love styles. Measures used to assess these various approaches are discussed briefly. There is much research on love, forcing selective coverage of topics, including communication of love, love styles, cross-cultural aspects of love, love and sexuality, love and happiness/well-being, and a new entry into the variable mix: love and respect. Clinical psychology and even psychoanalysis have recognized the centrality of a successful love relationship for the full development and emotional stability of most people. Love stands at the center of many aspects of human life. It is time that all of psychology, and the funding agencies, fully recognize the centrality and power of love. Until that happens, romantic love is the giant elephant that is unseen in psychology's living room.