21,908 research outputs found
Stronger sexual desires only predict bold romantic intentions and reported infidelity when self-control is low
© 2014 The Australian Psychological Society. Objective: The present research examined whether people with lower self-control were more likely to act in accordance with their sexual desires in romantic situations. Specifically, we tested the hypothesis that sexual desires would be positively related to infidelity and courting intentions, but only when self-control was dispositionally low or temporarily impaired. Method: In Study 1, 331 participants who were recruited online completed survey measures of dispositional self-control, general sexual desire, and past infidelity. In Study 2, 120 undergraduate students were randomly allocated to either a depletion (low self-control) or control (high self-control) condition. Following the self-control manipulation, all participants completed implicit and explicit measures of courting intentions, and indicated the likelihood they would cheat on a long-term partner in an imagined scenario. Results: Study 1 found that sexual desire positively predicted reported infidelity frequency for people with low, but not high, dispositional self-control. Study 2 found that stronger sexual desires predicted increased infidelity intentions, sitting closer to an attractive stranger in an imagined scenario, and asking this person out in a hypothetical encounter, but only among people who had been depleted of their self-control resources. Sexual desires were unrelated to all constructs when participants' self-control was dispositionally high (Study 1) or not depleted (Study 2). Conclusions: Our findings suggest that when self-control is high, sexual behaviour may be largely divorced from desire, relying instead on analysis of situational or other cognitive factors. Sexual behaviour may reflect genuine sexual predispositions, however, when self-control is dispositionally low or temporarily depleted
New mechanism for primordial black hole formation during reheating
In the scalar field dark matter model virialized halos present condensed central cores called boson stars. Considering the equivalent process during reheating, we look at the formation of primordial black holes (PBHs) through the gravitational collapse of structures virialized in this era. We present the criteria necessary for collapse of either the whole structure, or that of the central core, in terms of the threshold amplitude for the primordial density contrast. This is computed for both the free and the self-interacting scalar fields. We discuss the relevance of our results for the abundance of PBHs
Arginase from kiwifruit: properties and seasonal variation
The in vitro activity of arginase (EC 3.5.3.1) was investigated in youngest-mature leaves and roots (1-3 mm diameter) of kiwifruit vines (Actinidia deliciosa var. deliciosa) during an annual growth cycle, and enzyme from root material partially purified. No seasonal trend in the specific activity of arginase was observed in roots. Measurements in leaves, however, rose gradually during early growth and plateaued c. 17 weeks after budbreak. Changes in arginase activity were not correlated with changes in the concentration of arginine (substrate) or glutamine (likely end-product of arginine catabolism) in either tissue during the growth cycle. Purification was by (NH4)2SO4 precipitation and DEAE-cellulose chromatography. The kinetic properties of the enzyme, purified 60-fold over that in crude extracts, indicated a pH optimum of 8.8, and a Km (L-arginine) of 7.85 mM. Partially-purified enzyme was deactivated by dialysis against EDTA, and reactivated in the presence of Mn²⁺, Co²⁺, and Ni²⁺
Biochemical properties of Paracoccus denitrificans FnrP:Reactions with molecular oxygen and nitric oxide
In Paracoccus denitrificans, three CRP/FNR family regulatory proteins, NarR, NnrR and FnrP, control the switch between aerobic and anaerobic (denitrification) respiration. FnrP is a [4Fe-4S] cluster containing homologue of the archetypal O2 sensor FNR from E. coli and accordingly regulates genes encoding aerobic and anaerobic respiratory enzymes in response to O2, and also NO, availability. Here we show that FnrP undergoes O2-driven [4Fe-4S] to [2Fe-2S] cluster conversion that involves up to 2 O2 per cluster, with significant oxidation of released cluster sulfide to sulfane observed at higher O2 concentrations. The rate of the cluster reaction was found to be ~6-fold lower than that of E. coli FNR, suggesting that FnrP can remain transcriptionally active under microaerobic conditions. This is consistent with a role for FnrP in activating expression of the high O2 affinity cytochrome c oxidase under microaerobic conditions. Cluster conversion resulted in dissociation of the transcriptionally active FnrP dimer into monomers. Therefore, along with E. coli FNR, FnrP belongs to the subset of FNR proteins in which cluster type is correlated with association state. Interestingly, two key charged residues, Arg140 and Asp154, that have been shown to play key roles in the monomer-dimer equilibrium in E. coli FNR are not conserved in FnrP, indicating that different protomer interactions are important for this equilibrium. Finally, the FnrP [4Fe-4S] cluster is shown to undergo reaction with multiple NO molecules, resulting in iron nitrosyl species and dissociation into monomers
Recommended from our members
PacBio assembly of a Plasmodium knowlesi genome sequence with Hi-C correction and manual annotation of the SICAvar gene family.
Plasmodium knowlesi has risen in importance as a zoonotic parasite that has been causing regular episodes of malaria throughout South East Asia. The P. knowlesi genome sequence generated in 2008 highlighted and confirmed many similarities and differences in Plasmodium species, including a global view of several multigene families, such as the large SICAvar multigene family encoding the variant antigens known as the schizont-infected cell agglutination proteins. However, repetitive DNA sequences are the bane of any genome project, and this and other Plasmodium genome projects have not been immune to the gaps, rearrangements and other pitfalls created by these genomic features. Today, long-read PacBio and chromatin conformation technologies are overcoming such obstacles. Here, based on the use of these technologies, we present a highly refined de novo P. knowlesi genome sequence of the Pk1(A+) clone. This sequence and annotation, referred to as the 'MaHPIC Pk genome sequence', includes manual annotation of the SICAvar gene family with 136 full-length members categorized as type I or II. This sequence provides a framework that will permit a better understanding of the SICAvar repertoire, selective pressures acting on this gene family and mechanisms of antigenic variation in this species and other pathogens
Using unstructured profile information for gender classification of Portuguese and English
This paper reports experiments on automatically detecting the gender of Twitter users, based on unstructured information found on their Twitter profile. A set of features previously proposed is evaluated on two datasets of English and Portuguese users, and their performance is assessed using several supervised and unsupervised approaches, including Naive Bayes variants, Logistic Regression, Support Vector Machines, Fuzzy c-Means clustering, and k-means. Results show that features perform well in both languages separately, but even best results were achieved when combining both languages. Supervised approaches reached 97.9 % accuracy, but Fuzzy c-Means also proved suitable for this task achieving 96.4 % accuracy.info:eu-repo/semantics/acceptedVersio
Early stages of the HFCVD process on multi-vicinal silicon surfaces studied by electron microscopy probes (SEM, TEM)
In this paper, we show that silicon dimples are suitable samples to study diamond nucleation on a controlled distribution of defects by SEM FEG and HRTEM observations. Indeed, multi-vicinal surfaces generated by a UHV thermal treatment have been characterised by STM experiments. On these terraces, we observed a strong increase of the nucleation density higher than two orders of magnitude compared to pristine silicon samples. Moreover, a preferential location of diamond nuclei along the steps is reported. This result is explained by the large surface diffusion length of carbon species compared to the terrace's width. Indeed, during the early stages of growth, oriented silicon carbide nano-crystals are observed with the relationship SiC(220)//Si(220)
Neurogenic switching: a hypothesis for a mechanism for shifting the site of inflammation in allergy and chemical sensitivity.
Neurogenic switching is proposed as a hypothesis for a mechanism by which a stimulus at one site can lead to inflammation at a distant site. Neurogenic inflammation occurs when substance P and other neuropeptides released from sensory neurons produce an inflammatory response, whereas immunogenic inflammation results from the binding of antigen to antibody or leukocyte receptors. There is a crossover mechanism between these two forms of inflammation. Neurogenic switching is proposed to result when a sensory impulse from a site of activation is rerouted via the central nervous system to a distant location to produce neurogenic inflammation at the second location. Neurogenic switching is a possible explanation for systemic anaphylaxis, in which inoculation of the skin or gut with antigen produces systemic symptoms involving the respiratory and circulatory systems, and an experimental model of anaphylaxis is consistent with this hypothesis. Food-allergy-iducing asthma, urticaria, arthritis, and fibromyalgia are other possible examples of neurogenic switching. Neurogenic switching provides a mechanism to explain how allergens, infectious agents, irritants, and possibly emotional stress can exacerbate conditions such as migraine, asthma, and arthritis. Because neurogenic inflammation is known to be triggered by chemical exposures, it may play a role in the sick building syndrome and the multiple chemical sensitivity syndrome. Thus neurogenic switching would explain how the respiratory irritants lead to symptoms at other sites in these disorders
Enhancement of vaccinia virus based oncolysis with histone deacetylase inhibitors
Histone deacetylase inhibitors (HDI) dampen cellular innate immune response by decreasing interferon production and have been shown to increase the growth of vesicular stomatitis virus and HSV. As attenuated tumour-selective oncolytic vaccinia viruses (VV) are already undergoing clinical evaluation, the goal of this study is to determine whether HDI can also enhance the potency of these poxviruses in infection-resistant cancer cell lines. Multiple HDIs were tested and Trichostatin A (TSA) was found to potently enhance the spread and replication of a tumour selective vaccinia virus in several infection-resistant cancer cell lines. TSA significantly decreased the number of lung metastases in a syngeneic B16F10LacZ lung metastasis model yet did not increase the replication of vaccinia in normal tissues. The combination of TSA and VV increased survival of mice harbouring human HCT116 colon tumour xenografts as compared to mice treated with either agent alone. We conclude that TSA can selectively and effectively enhance the replication and spread of oncolytic vaccinia virus in cancer cells. © 2010 MacTavish et al
Preserved neural dynamics across animals performing similar behaviour
Animals of the same species exhibit similar behaviours that are advantageously adapted to their body and environment. These behaviours are shaped at the species level by selection pressures over evolutionary timescales. Yet, it remains unclear how these common behavioural adaptations emerge from the idiosyncratic neural circuitry of each individual. The overall organization of neural circuits is preserved across individuals1 because of their common evolutionarily specified developmental programme2-4. Such organization at the circuit level may constrain neural activity5-8, leading to low-dimensional latent dynamics across the neural population9-11. Accordingly, here we suggested that the shared circuit-level constraints within a species would lead to suitably preserved latent dynamics across individuals. We analysed recordings of neural populations from monkey and mouse motor cortex to demonstrate that neural dynamics in individuals from the same species are surprisingly preserved when they perform similar behaviour. Neural population dynamics were also preserved when animals consciously planned future movements without overt behaviour12 and enabled the decoding of planned and ongoing movement across different individuals. Furthermore, we found that preserved neural dynamics extend beyond cortical regions to the dorsal striatum, an evolutionarily older structure13,14. Finally, we used neural network models to demonstrate that behavioural similarity is necessary but not sufficient for this preservation. We posit that these emergent dynamics result from evolutionary constraints on brain development and thus reflect fundamental properties of the neural basis of behaviour
- …