917 resultados para ambiguous zeroes
Resumo:
Stereotypies are abnormal repetitive behaviour patterns that are highly prevalent in laboratory mice and are thought to reflect impaired welfare. Thus, they are associated with impaired behavioural inhibition and may also reflect negative affective states. However, in mice the relationship between stereotypies and behavioural inhibition is inconclusive, and reliable measures of affective valence are lacking. Here we used an exploration based task to assess cognitive bias as a measure of affective valence and a two-choice guessing task to assess recurrent perseveration as a measure of impaired behavioural inhibition to test mice with different forms and expression levels of stereotypic behaviour. We trained 44 CD- 1 and 40 C57BL/6 female mice to discriminate between positively and negatively cued arms in a radial maze and tested their responses to previously inaccessible ambiguous arms. In CD-1 mice (i) mice with higher stereotypy levels displayed a negative cognitive bias and this was influenced by the form of stereotypy performed, (ii) negative cognitive bias was evident in back-flipping mice, and (iii) no such effect was found in mice displaying bar-mouthing or cage-top twirling. In C57BL/6 mice neither route-tracing nor bar-mouthing was associated with cognitive bias, indicating that in this strain these stereotypies may not reflect negative affective states. Conversely, while we found no relation of stereotypy to recurrent perseveration in CD-1 mice, C57BL/6 mice with higher levels of route-tracing, but not bar-mouthing made more repetitive responses in the guessing task. Our findings confirm previous research indicating that the implications of stereotypies for animal welfare may strongly depend on the species and strain of animal as well as on the form and expression level of the stereotypy. Furthermore, they indicate that variation in stereotypic behaviour may represent an important source of variation in many animal experiments.
Resumo:
Meg Cabot’s young adult (YA) novel series The Princess Diaries (2000-2009) is one of many modern-day examples of attempts to redefine what Western society considers the classic princess narrative: the story of a beautiful princess passively waiting for Prince Charming. As critics such as Kay Stone and Sarah Rothschild emphasize, the fictional princess is traditionally linked to notions of ideal femininity which, in turn, makes princess stories interesting texts from a feminist perspective. Rothschild notes a surge in YA princess novels in recent years, with YA writers such as Cabot aiming to challenge the traditional image of the princess as a passive feminine stereotype in their re-workings of the princess story. Previous feminist research on The Princess Diaries series celebrates the main character Mia as a symbol of third wave feminism and as such, a positive role model for Cabot’s predominantly young, female readers. Mia’s characteristic Dr Martens boots are frequently cited as an example of how greatly Mia differs from her princess predecessors. However, these critics ignore important changes in Mia’s personality over the course of the series. By the end of the series, the Dr Martens-wearing heroine introduced in the first book has replaced her combat boots with high heels. In my thesis, I will argue that Mia’s transformation in terms of appearance and preoccupation with mainstream fashion, from quirky outsider to stereotype girly girl, complicates the idea of The Princess Diaries series as feminist texts. Moreover, previous feminist research largely ignores diary writing’s prominent role in the series, and the ways in which the diary format influences the reader-narrator relationship in the novels. In my feminist reading of The Princess Diaries series, I therefore use Mia’s diary writing and the diary format of the series as my starting points. I argue that while Mia’s diary writing is portrayed as empowering, and thereby inspiring, the diary format as a narrative structure creates a rather ambiguous tone and effect; questioning but simultaneously conforming to traditional, restricting notions of femininity.
Resumo:
Perceptual rivalry is an oscillation of conscious experience that takes place despite univarying, if ambiguous, sensory input. Much current interest is focused on the controversy over the neural site of binocular rivalry, a variety of perceptual rivalry for which a number of different cortical regions have been implicated. Debate continues over the relative role of higher levels of processing compared with primary visual cortex and the suggestion that different forms of rivalry involve different cortical areas. Here we show that the temporal pattern of disappearance and reappearance in motion-induced blindness (MIB) (Bonneh et al, 2001 Nature 411 798-801) is highly correlated with the pattern of oscillation reported during binocular rivalry in the same individual. This correlation holds over a wide range of inter-individual variation. Temporal similarity in the two phenomena was strikingly confirmed by the effects of the hallucinogen LSD, which produced the same, extraordinary, pattern of increased rhythmicity in both kinds of perceptual oscillation. Furthermore, MIB demonstrates the two properties previously considered characteristic of binocular rivalry. Namely the distribution of dominance periods can be approximated by a gamma distribution and, in line with Levelt's second proposition of binocular rivalry, predominance of one perceptual phase can be increased through a reduction in the predominance time of the opposing phase. We conclude that (i) MIB is a form of perceptual rivalry, and (ii) there may be a common oscillator responsible for timing aspects of all forms of perceptual rivalry.
Resumo:
Since the 1980s, numerous studies conducted in the United States have attempted to estimate the prevalence of supplement use among the population (e.g., the National Health and Nutrition Survey and the National Health Interview Surveys). Despite these efforts, the true extent of supplement use is unclear. The literature pertaining to the prevalence of supplement use refers to a confusing array of ambiguous terms. Forming accurate conclusions about supplement use is confounded by differences in terminology and methodology between studies. Direct comparisons between studies are therefore inherently problematic. The emphasis in future investigations should be on standardizing the study design; recording data on daily, weekly, or even monthly use in order to establish the safety and efficacy of supplement use; and adopting a consistent, uniform definition of the term supplement.
The preparation of reach-to-grasp movements in adults, children, and children with movement problems
Resumo:
This study explored the use of advance information in the control of reach-to-grasp movements. The paradigm required participants to reach and grasp illuminated blocks with their right hand. Four target blocks were positioned on a table surface, two each side of the mid-saggital plane. In the complete precue condition, advance information precisely specified target location. In the partial precue condition, advance information indicated target location relative to the midsaggital plane (left or right). In the null condition, the advance information was entirely ambiguous. Participants produced fastest responses in the complete precue condition, intermediate response times in the partial condition, and the slowest responses in the null condition. This result was observed in adults and four groups of children including a group aged 4-6 years. In contrast, children with Developmental Coordination Disorder (DCD, n = 11, aged 7-13 years) showed no advantage of partial precueing. Movement duration was determined by target location but was unaffected by precue condition. Movement duration was a clear function of age apart from children in the DCD group who showed equivalent movement times to those of the youngest children. These findings provide important insights into the control of reach-to-grasp movements and highlight that partial cues are exploited by children as young as 4 years but are not used in situations of abnormal development.
Resumo:
It is increasingly asserted that the disagreements of abstract principle between adversaries in the euthanasia debate fail to account for the complex, particular and ambiguous experiences of people at the end of their lives. A greater research effort into experiences, meaning, connection, vulnerability and motivation is advocated, during which the euthanasia 'question' should remain open. I argue that this is a normative strategy, which is felicitous to the status quo and further medicalises the end of life, but which masquerades as a value-neutral assertion about needing more knowledge.
Resumo:
In just over a decade, the use of molecular approaches for the recognition of parasites has become commonplace. For trematodes, the internal transcribed spacer region of ribosomal DNA (ITS rDNA) has become the default region of choice. Here, we review the findings of 63 studies that report ITS rDNA sequence data for about 155 digenean species from 19 families, and then review the levels of variation that have been reported and how the variation has been interpreted. Overall, complete ITS sequences (or ITS1 or ITS2 regions alone) usually distinguish trematode species clearly, including combinations for which morphology gives ambiguous results. Closely related species may have few base differences and in at least one convincing case the ITS2 sequences of two good species are identical. In some cases, the ITS1 region gives greater resolution than the ITS2 because of the presence of variable repeat units that are generally lacking in the ITS2. Intraspecific variation is usually low and frequently apparently absent. Information on geographical variation of digeneans is limited but at least some of the reported variation probably reflects the presence of multiple species. Despite the accepted dogma that concerted evolution makes the individual representative of the entire species, a significant number of studies have reported at least some intraspecific variation. The significance of such variation is difficult to assess a posteriori, but it seems likely that identification and sequencing errors account for some of it and failure to recognise separate species may also be significant. Some reported variation clearly requires further analysis. The use of a yardstick to determine when separate species should be recognised is flawed. Instead, we argue that consistent genetic differences that are associated with consistent morphological or biological traits should be considered the marker for separate species. We propose a generalised approach to the use of rDNA to distinguish trematode species.
Resumo:
Selection of machine learning techniques requires a certain sensitivity to the requirements of the problem. In particular, the problem can be made more tractable by deliberately using algorithms that are biased toward solutions of the requisite kind. In this paper, we argue that recurrent neural networks have a natural bias toward a problem domain of which biological sequence analysis tasks are a subset. We use experiments with synthetic data to illustrate this bias. We then demonstrate that this bias can be exploitable using a data set of protein sequences containing several classes of subcellular localization targeting peptides. The results show that, compared with feed forward, recurrent neural networks will generally perform better on sequence analysis tasks. Furthermore, as the patterns within the sequence become more ambiguous, the choice of specific recurrent architecture becomes more critical.
Resumo:
A granodiorite from Akilia, southwest Greenland, previously suggested to date putative life-bearing rocks to greater than or equal to3.84 Ga, is re-investigated using whole-rock major and trace-element geochemistry, and detailed cathodoluminescence image-guided secondary ion mass spectrometer analyses of zircon U-Th-Pb and rare earth elements. Complex zircon internal structure reveals three episodes of zircon growth and/or recrystallization dated to c. 3.84 Ga, 3.62 Ga and 2.71 Ga. Rare earth element abundances imply a significant role for garnet in zircon generation at 3.62 Ga and 2.71 Ga. The 3.62 Ga event is interpreted as partial melting of a c. 3.84 Ga grey gneiss precursor at granulite facies with residual garnet. Migration of this 3.62 Ga magma (or melt-crystal mush) away from the melt source places a maximum age limit on any intrusive relationship. These early Archaean relationships have been complicated further by isotopic reworking in the 2.71 Ga event, which could have included a further episode of partial melting. This study highlights a general problem associated with dating thin gneissic veins in polyphase metamorphic terranes, where field relationships may be ambiguous and zircon inheritance can be expected.
Resumo:
In the English literature, facial approximation methods have been commonly classified into three types: Russian, American, or Combination. These categorizations are based on the protocols used, for example, whether methods use average soft-tissue depths (American methods) or require face muscle construction (Russian methods). However, literature searches outside the usual realm of English publications reveal key papers that demonstrate that the Russian category above has been founded on distorted views. In reality, Russian methods are based on limited face muscle construction, with heavy reliance on modified average soft-tissue depths. A closer inspection of the American method also reveals inconsistencies with the recognized classification scheme. This investigation thus demonstrates that all major methods of facial approximation depend on both face anatomy and average soft-tissue depths, rendering common method classification schemes redundant. The best way forward appears to be for practitioners to describe the methods they use (including the weight each one gives to average soft-tissue depths and deep face tissue construction) without placing them in any categorical classificatory group or giving them an ambiguous name. The state of this situation may need to be reviewed in the future in light of new research results and paradigms.
Resumo:
The Australian career of the young American actor Minnie Tittell Brune exemplifies the complex cultural and economic forces operating on the institution of live theatre at the beginning of the twentieth century. Brune focalizes the contemporary processes which reconstituted the international institution of mass entertainment out of the traditional cultural practices of theatre. The theatrical star is seen as both engaging with and resisting the commodification of her labour power; image and talent resulting from her ambiguous industrial role as magnetic 'star' and as managerial commodity. However, the iconic and affective power of the actor evokes strong attachment from significant sections of the newly heterosocial popular audience, in particular from the gallery girls, the young female audience who idolized Brune as a performative personality enacting social self-realization and glamorous transformation. Through reading Brume's repertoire, her social persona as 'star' and her 'emotional' performative style, it is demonstrated how artistic retro-glamour, religious evangelicalism and discourses of sexuality and femininity serve to manage theatre's move into the mass-entertainment age.
Resumo:
The red fluorescent protein Rtms5H146S displays a transition from blue (absorbance λmax 590 nm) to yellow (absorbance λmax not, vert, similar453 nm) upon titration to low pH. The pKa of the reaction depends on the concentration of halide, offering promise for new expressible halide sensors. The protonation state involved in the low pH form of the chromophore remains, however, ambiguous. We report calculated excitation energies of different protonation states of an RFP chromophore model. These suggest that the relevant titration site is the phenoxy moiety of the chromophore, and the relevant base and conjugate acid are anionic and neutral chromophore species, respectively.
Resumo:
Recently Hupe and Rubin (2003, Vision Research 43 531 - 548) re-introduced the plaid as a form of perceptual rivalry by using two sets of drifting gratings behind a circular aperture to produce quasi-regular perceptual alternations between a coherent moving plaid of diamond-shaped intersections and the two sets of component 'sliding' gratings. We call this phenomenon plaid motion rivalry (PMR), and have compared its temporal dynamics with those of binocular rivalry in a sample of subjects covering a wide range of perceptual alternation rates. In support of the proposal that all rivalries may be mediated by a common switching mechanism, we found a high correlation between alternation rates induced by PMR and binocular rivalry. In keeping with a link discovered between the phase of rivalry and mood, we also found a link between PMR and an individual's mood state that is consistent with suggestions that each opposing phase of rivalry is associated with one or the other hemisphere, with the 'diamonds' phase of PMR linked with the 'positive' left hemisphere.
Resumo:
This research project addressed limitations identified in previous studies of role differences (victim vs. perpetrator) in evaluations of hurtful events. The study employed multiple methods (open-ended and structured retrospective reports and experience-sampling diary records), and involved a community sample of both dating and married couples. Retrospective reports indicated that the extent and direction of role-related differences varied markedly across dependent measures. Further, role differences were moderated by forgiveness, but not relationship status, relationship satisfaction, or event severity. Diary records pointed to the ambiguity inherent in many communication acts as contributing to differing perceptions of hurtful events. Results are discussed in terms of theories of interdependence and self-presentation and in terms of the complex and often ambiguous nature of couples' communication processes.
Resumo:
An experiment was conducted to examine the impact of homophobic attitudes and situational norms for helping on discriminatory behavior against a gay male. In a partial replication of Frey and Gaertner (1986), participants were asked to provide help to a confederate portrayed to be either gay or heterosexual who either requested help for himself (ambiguous situational norm) or for whom a third party requested help (unambiguous situational norm). Participants' levels of homophobia were assessed either before or after the main helping task. The results indicated that when norms for helping were ambiguous those participants higher in homophobia discriminated against the gay male, but only on subtle indicators of discrimination. In the unambiguous norm condition, participants higher in homophobia discriminated against the heterosexual male. Those lower in homophobia did not discriminate under either norm condition. The results show that it may be sufficient for those with prejudiced attitudes just to believe that it is not the wrong thing to do for their attitudes to be translated into some form of discriminatory behavior.