1,205 research outputs found
Measuring the speed of the conscious components of recognition memory: Remembering is faster than knowing.
Three experiments investigated response times (RTs) for remember and know responses in recognition memory. RTs to remember responses were faster than RTs to know responses, regardless of whether the remember–know decision was preceded by an old/new decision (two-step procedure) or was made without a preceding old/new decision (one-step procedure). The finding of faster RTs for R responses was also found when remember–know decisions were made retrospectively. These findings are inconsistent with dual-process models of recognition memory, which predict that recollection is slower and more effortful than familiarity. Word frequency did not influence RTs, but remember responses were faster for words than for nonwords. We argue that the difference in RTs to remember and know responses reflects the time taken to make old/new decisions on the basis of the type of information activated at test
Neuropharmacological mechanisms underlying the effect of medial preoptic area dopamine in the sexual behaviour of female rats
Dopamine (DA) in the medial preoptic area (mPOA) mediates the display of solicitational behaviours in the female rat. Previous work from my Masters’ thesis demonstrated that a DA D1 receptor (D1R)-mediated excitatory state appears to occur in females hormonally-primed with both estradiol benzoate (EB) and progesterone (P). Conversely, a DA D2 receptor (D2R)-mediated inhibitory state appears to occur in females primed only with EB. The goals of the current thesis were to understand the mechanisms by which this control occurs, and to incorporate this understanding into the bigger framework of neural control underlying female sexual behaviour. To accomplish this, a variety of techniques were utilized. First, the same behavioural results observed previously were replicated through an endogenous alteration of DA release. It was found that administration of ascorbic acid produced an increase in solicitational, but not consummatory behaviours, in females in both hormonal conditions. Three techniques were then employed to study changes in DA receptors (DAR) in the mPOA under three hormonal profiles. Immunohistochemistry determined the number of neurons in the mPOA containing D1R or D2R, DAR protein levels were analyzed using Western blotting, and DAR functional binding levels were examined using autoradiography. The results from all three techniques supported the previous behavioural findings that EB+P females have a higher D1R/D2R ratio, and thus a D1R-mediated system, and EB-alone females have a lower D1R/D2R ratio, and thus a D2R-mediated system. Finally, fluorescence immunohistochemistry was used to map connections from the mPOA to areas known to regulate female sexual behaviour. These pathways were investigated for neuronal type and presence of DAR under different hormonal conditions. Modifications were found, demonstrating that ovarian steroids alter the mechanisms underlying solicitational behaviour via projections to other areas implicated in female sexual behaviour. A conceptual model is presented here that integrates the data in this thesis along with other known networks that control female sexual behaviour. This model has important implications for the treatment of female sexual desire disorders, and places a central role of DA terminals in the mPOA in the regulation of motivated behaviours in general
The role of dopamine receptors in the medial preoptic area on the sexual behaviour of female rats
The medial preoptic area (mPOA) is critical in the control of male sexual behaviour, and dopamine (DA) plays an important role within it However, both the roles of DA and the mPOA in female sexual behaviour are not fully understood, with few studies producing consistent data. In the present set of experiments the role of DA within the mPOA on the full cascade of female sexual behaviour is investigated. Ovariectomized female rats were bilaterally cannulated into the mPOA and hormonally primed either fully, with estradiol benzoate (EB) and progesterone (P), or partially with EB-alone. Since it was hypothesized that DA plays a facilitative role in female sexual behaviour, a nonselective DA receptor, and selective DA Dl and D2 receptor agonists (apomorphine, SKF 38393 and quinpirole, respectively) were infused to EB-alone females and nonselective DA receptor, and selective DA Dl and D2 receptor antagonists (flupenthixol, SCH 23390, and raclopride, respectively) were infused to EB+P rats. Copulatory behaviour was then immediately tested over a period of thirty minutes in a bilevel chamber with a sexually experienced male. Precopulatory behaviours were increased in EB-alone females following infusions of a low dose (0.25 æg) of apomorphine and both a low (0.05 æg) and a high dose (0.2 æg) of quinpirole. Hops and/or darts were decreased following infusion of a low dose (0.05 æg) of SKF 38393. In EB+P females, precopulatory behaviours were decreased following infusions of a high dose (4.0 æg) of SCH 23390, but were increased following infusions of a high dose (4.0 æg) of raclopride. Flupenthixol had no effect on sexual behaviour. These results suggest that the ratio of DA Dl/D2 activity within the mPOA of female rats is critical for the expression of precopulatory behaviours, and may work within brain areas responsible for stimulating lordosis to control the timing of female sexual behaviour
Isolating the effects of visual imagery on prospective memory
Two experiments investigated the role of visual imagery in prospective memory (PM). In experiment 1, 140 participants completed a general knowledge quiz which included a PM task of writing a letter ‘X’ next to any questions that referred to space. Participants either visualised themselves performing this task, verbalised an implementation intention about the task, did both, or did neither. Performance on the PM task was enhanced in both conditions involving visual imagery but not by implementation intentions alone. In experiment 2, 120 participants imagined themselves writing a letter ‘X’ next to questions about space, or in a bizarre imagery condition imagined themselves drawing an alien next to those questions. Relative to the control condition, PM was significantly enhanced when participants imagined writing a letter ‘X’ next to the target questions, but not by the bizarre imagery task. The findings indicate that the robust effects of imagery observed in retrospective memory also extend to PM
Influence of oxidative stress, diaphragm fatigue, and inspiratory muscle training on the plasma cytokine response to maximum sustainable voluntary ventilation
The influence of oxidative stress, diaphragm fatigue, and inspiratory muscle training (IMT) on the cytokine response to maximum sustainable voluntary ventilation (MSVV) is unknown. Twelve healthy males were divided equally into an IMT or placebo (PLA) group, and before and after a 6-wk intervention they undertook, on separate days, 1h of (1) passive rest and (2) MSVV, whereby participants undertook volitional hyperpnea at rest that mimicked the breathing and respiratory muscle recruitment patterns commensurate with heavy cycling exercise. Plasma cytokines remained unchanged during passive rest. There was a main effect of time (P < 0.01) for plasma interleukin-1 (IL-1) and interleukin-6 (IL-6) concentrations and a strong trend (P = 0.067) for plasma interleukin-1 receptor antagonist concentration during MSVV. Plasma IL-6 concentration was reduced after IMT by 27 + 18% (main effect of intervention, P = 0.029), whereas there was no change after PLA (P = 0.753). There was no increase in a systemic marker of oxidative stress [DNA damage in peripheral blood mononuclear cells (PBMC)], and diaphragm fatigue was not related to the increases in plasma IL-1 and IL-6 concentrations. A dose-response relationship was observed between respiratory muscle work and minute ventilation and increases in plasma IL-6 concentration. In conclusion, increases in plasma IL-1 and IL-6 concentrations during MSVV were not due to diaphragm fatigue or DNA damage in PBMC. Increases in plasma IL-6 concentration during MSVV are attenuated following IMT, and the plasma IL-6 response is dependent upon the level of respiratory muscle work and minute ventilation
Binding Energy and the Fundamental Plane of Globular Clusters
A physical description of the fundamental plane of Galactic globular clusters
is developed which explains all empirical trends and correlations in a large
number of cluster observables and provides a small but complete set of truly
independent constraints on theories of cluster formation and evolution in the
Milky Way. Within the theoretical framework of single-mass, isotropic King
models, it is shown that (1) 39 regular (non--core-collapsed) globulars with
measured core velocity dispersions share a common V-band mass-to-light ratio of
1.45 +/- 0.10, and (2) a complete sample of 109 regular globulars reveals a
very strong correlation between cluster binding energy and total luminosity,
regulated by Galactocentric position: E_b \propto (L^{2.05} r_{\rm gc}^{-0.4}).
The observational scatter about either of these two constraints can be
attributed fully to random measurement errors, making them the defining
equations of a fundamental plane for globular clusters. A third, weaker
correlation, between total luminosity and the King-model concentration
parameter, c, is then related to the (non-random) distribution of globulars on
the plane. The equations of the FP are used to derive expressions for any
cluster observable in terms of only L, r_{\rm gc}, and c. Results are obtained
for generic King models and applied specifically to the globular cluster system
of the Milky Way.Comment: 60 pages with 19 figures, submitted to Ap
Roll-Back Eradication of Bovine Tuberculosis (TB) From Wildlife in New Zealand: Concepts, Evolving Approaches, and Progress
The New Zealand government and agricultural industries recently jointly adopted the goal of nationally eradicating bovine tuberculosis (TB) from livestock and wildlife reservoirs by 2055. Only Australia has eradicated TB from a wildlife maintenance host. Elsewhere the disease is often self-sustaining in a variety of wildlife hosts, usually making eradication an intractable problem. The New Zealand strategy for eradicating TB from wildlife is based on quantitative assessment using a Bayesian “Proof of Freedom” framework. This is used to assess the probability that TB has been locally eradicated from a given area. Here we describe the framework (the concepts, methods and tools used to assess TB freedom and how they are being applied and updated). We then summarize recent decision theory research aimed at optimizing the balance between the risk of falsely declaring areas free and the risk of overspending on disease management when the disease is already locally extinct. We explore potential new approaches for further optimizing the allocation of management resources, especially for places where existing methods are impractical or expensive, including using livestock as sentinels. We also describe how the progressive roll-back of locally eradicated areas scales up operationally and quantitatively to achieve and confirm eradication success over the entire country. Lastly, we review the progress made since the framework was first formally adopted in 2011. We conclude that eradication of TB from New Zealand is feasible, and that we are well on the way to achieving this outcome
The maintenance of urban circulation: An operational logic of infrastructural control
This paper examines the increased visibility of urban infrastructures occurring through a close coupling of information technologies and the selective integration of urban services. It asks how circulatory flow is managed in the contemporary city, by focusing on the emergence of new forms of governmentality associated with “smart” technologies. Drawing on Foucault’s governmentality, and based on a case study of Rio de Janeiro’s Operations Centre (COR), the paper argues that new understandings of the city are being developed, representing a new mode of urban infrastructure based on the partial and selective rebundling of splintered networks and fragmented urban space. The COR operates through a “un-black boxing” of urban infrastructures, where the extension of control room logics to the totality of the city points to their fragility and the continuous effort involved in their operational accomplishment. It also functions through a collapse in relations of control—of the everyday and the emergency—, which, enabled by the incorporation of the public in operational control, further raise public awareness of urban infrastructures. These characteristics point to a specific form of urban governmentality based on the operationalisation of infrastructural flows and the development of novel ways of seeing and engaging with the city
The effect of survival processing on memory for pictures depends on how memory is tested
Two experiments investigated the effects of survival processing on memory for pictures of objects.
In experiment 1, participants were presented with 32 pictures of common objects and rated them
for their relevance to a survival scenario, a moving home scenario, or for pleasantness. In a surprise
recall test, participants in the survival condition recalled more of the verbal labels of the objects
than participants in the moving and pleasantness conditions. In experiment 2, participants
rated 64 pictures of objects in survival, moving home, or pleasantness conditions. Memory for
visual detail was assessed using a forced-choice recognition test in which participants had to
decide which of two highly similar pictures was the one they rated at study. In contrast to the
results of experiment 1, correct recognition scores were highest in the pleasantness condition
and lowest in the survival condition. This pattern suggests that survival processing enhances
memory for objects but not for precise visual detail. The findings are consistent with the view
that rating objects for their survival value directs attention to the potential uses of the objects.
They also emphasise the importance of the match between encoding and retrieval processes in
the survival processing paradigm
2,5-Dimethyl-1,3-dinitrobenzene
The title compound, C8H8N2O4, was prepared via the nitration of p-xylene. The molecules are stacked along the c axis in an antiparallel manner. The two nitro groups are rotated relative to the benzene ring with dihedral angles of 44.50 (7) and 31.67 (8)°. The tilt of the nitro groups allows the formation of C—H⋯O interactions between the ring C—H and nitro groups of adjacent molecules creating puckered sheets perpendicular to the c axis. The H atoms of the methyl group in the 5-position are disordered (60° rotation) with an occupancy of 0.616 (19) for the major component. The crystal was found to be a non-merohedral twin with a twin law [−1 −0.002 0.005, 0.00031 −1 0.002, 0.118 −0.007 1] corresponding to a rotation of 180° about the reciprocal axis (001) and refined to give a minor component fraction of 0.320 (2)
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