4,940 research outputs found
Cross-orientation masking is speed invariant between ocular pathways but speed dependent within them
No full textIn human (D. H. Baker, T. S. Meese, & R. J. Summers, 2007b) and in cat (B. Li, M. R. Peterson, J. K. Thompson, T. Duong, & R. D. Freeman, 2005; F. Sengpiel & V. Vorobyov, 2005) there are at least two routes to cross-orientation suppression (XOS): a broadband, non-adaptable, monocular (within-eye) pathway and a more narrowband, adaptable interocular (between the eyes) pathway. We further characterized these two routes psychophysically by measuring the weight of suppression across spatio-temporal frequency for cross-oriented pairs of superimposed flickering Gabor patches. Masking functions were normalized to unmasked detection thresholds and fitted by a two-stage model of contrast gain control (T. S. Meese, M. A. Georgeson, & D. H. Baker, 2006) that was developed to accommodate XOS. The weight of monocular suppression was a power function of the scalar quantity ‘speed’ (temporal-frequency/spatial-frequency). This weight can be expressed as the ratio of non-oriented magno- and parvo-like mechanisms, permitting a fast-acting, early locus, as befits the urgency for action associated with high retinal speeds. In contrast, dichoptic-masking functions superimposed. Overall, this (i) provides further evidence for dissociation between the two forms of XOS in humans, and (ii) indicates that the monocular and interocular varieties of XOS are space/time scale-dependent and scale-invariant, respectively. This suggests an image-processing role for interocular XOS that is tailored to natural image statistics—very different from that of the scale-dependent (speed-dependent) monocular variety
A socio-rhetorical exegesis of 1 Timothy 2:8-15
No full textIn this thesis two interralted tasks are undertaken. First, this thesis is an attempt to gain mastery of an interpretive methodology, namely, socio-rhetorical analysis. Second, by looking at a crucial text that has major implications for the contemporary church, I have applied this method of analysis to a particularly Scriptural text, namely, 1 Timothy 2:8-15. In this thesis I demonstrate using socio-rhetorical analysis that the discourse contained in 1 Timothy 2:8-15 constitutes baptised patriarchal cultural practices and traditions from the dominant Greco-Roman culture of the first century. I demonstrate, therefore, that the portrayal of women in the text reflects a cultural imperative, and not a theological imperative, that was co-opted from the ""secular"" Greco-Roman culture of the day and transposed, using Scriptural texts as authentication, into the Christian community at Ephesus. Thus the text is simply re-enforcing normative Greco-Roman cultural values upon Christian women and camouflaging it as a Christian norm in order to persuade women to conform to patriarchal cultural standards. Such persuasion, however, is hardly required unless one has already accepted cultural assumptions about the subordination and silencing (objectification) of women in an androcentric hegemonic culture
Binocular contrast interactions: dichoptic masking is not a single process
No full textTo decouple interocular suppression and binocular summation we varied the relative phase of mask and target in a 2IFC contrast-masking paradigm. In Experiment I, dichoptic mask gratings had the same orientation and spatial frequency as the target. For in-phase masking, suppression was strong (a log-log slope of ~1) and there was weak facilitation at low mask contrasts. Anti-phase masking was weaker (a log-log slope of ~0.7) and there was no facilitation. A two-stage model of contrast gain control (Meese, Georgeson and Baker, 2006, J. Vis, 6: 1224-1243) provided a good fit to the in-phase results and fixed its free parameters. It made successful predictions (with no free parameters) for the anti-phase results when (A) interocular suppression was phase-indifferent but (B) binocular summation was phase sensitive. Experiments II and III showed that interocular suppression comprised two components: (i) a tuned effect with an orientation bandwidth of ~±33° and a spatial frequency bandwidth of >3 octaves, and (ii) an untuned effect that elevated threshold by a factor of between 2 and 4. Operationally, binocular summation was more tightly tuned, having an orientation bandwidth of ~±8°, and a spatial frequency bandwidth of ~0.5 octaves. Our results replicate the unusual shapes of the in-phase dichoptic tuning functions reported by Legge (1979, Vis Res, 69: 838-847). These can now be seen as the envelope of the direct effects from interocular suppression and the indirect effect from binocular summation, which contaminates the signal channel with a mask that has been suppressed by the target
Binocular contrast vision at and above threshold
No full textA fundamental problem for any visual system with binocular overlap is the combination of information from the two eyes. Electrophysiology shows that binocular integration of luminance contrast occurs early in visual cortex, but a specific systems architecture has not been established for human vision. Here, we address this by performing binocular summation and monocular, binocular, and dichoptic masking experiments for horizontal 1 cycle per degree test and masking gratings. These data reject three previously published proposals, each of which predict too little binocular summation and insufficient dichoptic facilitation. However, a simple development of one of the rejected models (the twin summation model) and a completely new model (the two-stage model) provide very good fits to the data. Two features common to both models are gently accelerating (almost linear) contrast transduction prior to binocular summation and suppressive ocular interactions that contribute to contrast gain control. With all model parameters fixed, both models correctly predict (1) systematic variation in psychometric slopes, (2) dichoptic contrast matching, and (3) high levels of binocular summation for various levels of binocular pedestal contrast. A review of evidence from elsewhere leads us to favor the two-stage model
Evaluating Research Impact through Open Access to Scholarly Communication
No full textScientific research is a competitive business – in order to secure funding, promotion and tenure researchers must demonstrate their work has impact in their field. To maximise impact researchers undertake high priority research, aim to get results first, and publish in the highest impact journals. The Internet now presents a new opportunity to the scholarly author seeking higher impact: s/he can now make their work instantly accessible on the Web through author self-archiving. This growing body of open access literature (coupled with new publishing models that make journals available for-free to the reader) maximises research impact by maximising the number of people who can read it, and making it available sooner. Open access also provides a new opportunity for bibliometric research. This thesis describes the relatively recent phenomenon of open access to research literature, tools that were built to collect and analyse that literature, and the results of analyses of the effect of open access and its effect on author behaviour. It shows that articles self-archived by authors receive between 50-250% more citations, that rapid pre-printing on the Web has dramatically reduced the peak citation rate from over a year to virtually instant and how citation-impact – now widely used for evaluation – can be expanded to include a new web metric of download impact
Authorship of 2 Timothy: Neglected Viewpoints on Genre and Dating
No full textThis thesis will explore the authorship, genre, and date of Paul’s Second Letter to Timothy. 2 Timothy, alongside 1 Timothy and Titus, constitute what scholars term the “Pastoral Epistles”. The Pastoral Epistles identify themselves to be from the hand Paul. However, since the early 19th century, a majority of scholars have questioned this claim and argued in favor of a pseudonymous author who wrote in Paul’s name after his death. Consequently, they are often dated sometime after the death of Paul (~62 CE) and taken to be a reflection of late 1st century/2nd century Christianity. The differences between the Pastorals and Paul’s other letters in areas such as vocabulary, style, and theology are often cited in backing up this claim. This thesis first surveys what scholarship has to say about these differences and possible solutions. Subsequently, the case will be made for 2 Timothy’s uniqueness amongst the “Pastoral Epistles” and why the Pastoral Epistles should be studied as three separate letters rather than as a group. The focus will then turn to the consequences of grouping 2 Timothy with 1 Timothy and Titus and what consequences reconsideration of 2 Timothy’s dating and genre can have for our understanding of its nature and provenance
Contrast masking in strabismic amblyopia: attenuation, noise, interocular suppression and binocular summation
No full textTo investigate amblyopic contrast vision at threshold and above we performed pedestal-masking (contrast discrimination) experiments with a group of eight strabismic amblyopes using horizontal sinusoidal gratings (mainly 3 c/deg) in monocular, binocular and dichoptic configurations balanced across eye (i.e. five conditions). With some exceptions in some observers, the four main results were as follows. (1) For the monocular and dichoptic conditions, sensitivity was less in the amblyopic eye than in the good eye at all mask contrasts. (2) Binocular and monocular dipper functions superimposed in the good eye. (3) Monocular masking functions had a normal dipper shape in the good eye, but facilitation was diminished in the amblyopic eye. (4) A less consistent result was normal facilitation in dichoptic masking when testing the good eye, but a loss of this when testing the amblyopic eye. This pattern of amblyopic results was replicated in a normal observer by placing a neutral density filter in front of one eye. The two-stage model of binocular contrast gain control [Meese, T.S., Georgeson, M.A. & Baker, D.H. (2006). Binocular contrast vision at and above threshold. Journal of Vision 6, 1224–1243.] was ‘lesioned’ in several ways to assess the form of the amblyopic deficit. The most successful model involves attenuation of signal and an increase in noise in the amblyopic eye, and intact stages of interocular suppression and binocular summation. This implies a behavioural influence from monocular noise in the amblyopic visual system as well as in normal observers with an ND filter over one eye
sj-docx-1-asm-10.1177_10731911241237055 – Supplemental material for Development and Initial Validation of a Momentary Cannabis Craving Scale Within a Homogeneous Sample of U.S. Emerging Adults
No full textSupplemental material, sj-docx-1-asm-10.1177_10731911241237055 for Development and Initial Validation of a Momentary Cannabis Craving Scale Within a Homogeneous Sample of U.S. Emerging Adults by Christal N. Davis, Kathryn S. Gex, Lindsay M. Squeglia, Timothy J. Trull, Denis M. McCarthy, Nathaniel L. Baker, Kevin M. Gray, Aimee L. McRae-Clark and Rachel L. Tomko in Assessment</p
Large range sizes link fast life histories with high species richness across wet tropical tree floras
No full textUnderstanding how the traits of lineages are related to diversification is key for elucidating the origin of variation in species richness. Here, we test whether traits are related to species richness among lineages of trees from all major biogeographical settings of the lowland wet tropics. We explore whether variation in mortality rate, breeding system and maximum diameter are related to species richness, either directly or via associations with range size, among 463 genera that contain wet tropical forest trees. For Amazonian genera, we also explore whether traits are related to species richness via variation among genera in mean species-level range size. Lineages with higher mortality rates—faster life-history strategies—have larger ranges in all biogeographic settings and have higher mean species-level range sizes in Amazonia. These lineages also have smaller maximum diameters and, in the Americas, contain dioecious species. In turn, lineages with greater overall range size have higher species richness. Our results show that fast life-history strategies influence species richness in all biogeographic settings because lineages with these ecological strategies have greater range sizes. These links suggest that dispersal has been a key process in the evolution of the tropical forest flora.</p
Book Review: Sun Tzu in Space: What International Relations, History, and Science Fiction Teach Us About Our Future
No full textAuthor: Gregory D. Miller
Reviewed by: Lieutenant Colonel Timothy S. Martin, director, Defense Strategy Course, US Army War College, and Captain Stephanie St. Louis, strategic planner, Office of the Chief of Army Reserve, Fort Belvoir
Sun Tzu in Space combines an examination of history and science fiction to assess what humanity’s future in space could look like through an international relations lens. The reviewer sees it as “a pulse check on the potential for violent future conflicts” and recommends it for policymakers and science fiction enthusiasts alike.
©2025 Timothy G. Martin and Stephanie St. Louishttps://press.armywarcollege.edu/parameters_bookshelf/1108/thumbnail.jp
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