50 research outputs found
Subliminally Perceived Odours Modulate Female Intrasexual Competition: An Eye Movement Study
Background: Evidence suggests that subliminal odorants influence human perception and behavior. It has been hypothesized that the human sex-steroid derived compound 4,16-androstadien-3-one (androstadienone) functions as a human chemosignal. The most intensively studied steroid compound, androstadienone is known to be biologically relevant since it seems to convey information about male mate quality to women. It is unclear if the effects of androstadienone are menstrual cycle related. Methodology/Principal Findings: In the first experiment, heterosexual women were exposed to androstadienone or a control compound and asked to view stimuli such as female faces, male faces and familiar objects while their eye movements were recorded. In the second experiment the same women were asked to rate the level of stimuli attractiveness following exposure to the study or control compound. The results indicated that women at high conception risk spent more time viewing the female than the male faces regardless of the compound administered. Women at a low conception risk exhibited a preference for female faces only following exposure to androstadienone. Conclusions/Significance: We contend that a woman’s level of fertility influences her evaluation of potential competitors (e.g., faces of other women) during times critical for reproduction. Subliminally perceived odorants, such as androstadienone, might similarly enhance intrasexual competition strategies in women during fertility phases not critica
A genetic cause of Alzheimer disease: mechanistic insights from Down syndrome
Down syndrome, caused by an extra copy of chromosome 21, is associated with a greatly increased risk of early onset Alzheimer disease. It is thought that this risk is conferred by the presence of three copies of the gene encoding amyloid precursor protein (APP), an Alzheimer risk factor, although the possession of extra copies of other chromosome 21 genes may also play a role. Further study of the mechanisms underlying the development of Alzheimer disease in Down syndrome could provide insights into the mechanisms that cause dementia in the general population
Phylogenetic evidence for the invasion of a commercialized European Phasmarhabditis hermaphrodita lineage into North America and New Zealand
Biological control (biocontrol) as a component of pest management strategies reduces reliance on synthetic chemicals, and seemingly offers a natural approach that minimizes environmental impact. However, introducing a new organism to new environments as a classical biocontrol agent can have broad and unanticipated biodiversity effects and conservation consequences. Nematodes are currently used in a variety of commercial biocontrol applications, including the use of Phasmarhabditis hermaphrodita as an agent targeting pest slug and snail species. This species was originally discovered in Germany, and is generally thought to have European origins. P. hermaphrodita is sold under the trade name Nemaslug®, and is available only in European markets. However, this nematode species was discovered in New Zealand and the western United States, though its specific origins remained unclear. In this study, we analyzed 45 nematode strains representing eight different Phasmarhabditis species, collected from nine countries around the world. A segment of nematode mitochondrial DNA (mtDNA) was sequenced and subjected to phylogenetic analyses. Our mtDNA phylogenies were overall consistent with previous analyses based on nuclear ribosomal RNA (rRNA) loci. The recently discovered P. hermaphrodita strains in New Zealand and the United States had mtDNA haplotypes nearly identical to that of Nemaslug®, and these were placed together in an intraspecific monophyletic clade with high support in maximum likelihood and Bayesian analyses. We also examined bacteria that co-cultured with the nematode strains isolated in Oregon, USA, by analyzing 16S rRNA sequences. Eight different bacterial genera were found to associate with these nematodes, though Moraxella osloensis, the bacteria species used in the Nemaslug® formulation, was not detected. This study provided evidence that nematodes deriving from the Nemaslug® biocontrol product have invaded countries where its use is prohibited by regulatory agencies and not commercially available
Wybrane problemy projektowania mechatronicznego, red. T. Uhl, , KRiDM AGH, 1999 7.5 Sterowanie elastycznym ramieniem robota
Zasadniczymi problemami badawczymi analizowanymi w tym rozdziale s ¡: a) okre ¢ lenie metodyki oraz budowa i identyfikacja modelu matematycznego elastycznego ramienia robota wraz z nap £ dem, ujmuj ¡ cego wszystkie istotne zjawiska (w tym oscylacje i tarcie), b) wybór i realizacja odpowiedniej koncepcji układu sterowania w czasie rzeczywistym, zapewniaj ¡ cej:- wymagan ¡ dokładno¢¥ ¤ ¢ ledzenia sygnałów steruj ¡ cych,- zadowalaj ¡ c ¡ szybko¢¥ ¤ działania,- skuteczne tłumienie oscylacji,- odporno¢¥ ¤ na zmiany parametrów (zmiana obci¡§ ¦ e ¨ , nieliniowo ¢ ci i niestacjonarno¢¥ ¤ obiektu oraz otoczenia), c) weryfikacja uzyskanych rezultatów na stanowisku badawczym z modelem fizycznym. Opisany dalej proces prototypowania (projektowania, modelowania, symulacji i weryfikacji) sterowników jest oparty o podej ¢ cie mechatroniczne i zostanie przeprowadzony w ¢ rodowisku MATLAB/SIMULINK/RTW, z wykorzystaniem wirtualnych sterowników rezyduj ¡ cych w pami £ ci komputera. Do bada ¨ w czasie rzeczywistym wykorzystywane były wariantowo karta i oprogramowanie dSPACE lub komputer przemysłowy z systemem operacyjnym VxWorks. Celem opisanych bada ¨ jest opracowanie metodyki efektywnej syntezy algorytmó
Cytokine and Anti-Inflammatory Drug Effects on Brain Trauma and Alzheimer’s Disease Pathology in Transgenic Mice
There is a continuous interaction between neurons, glia and inflammatory cells in the normal brain that is exacerbated following trauma or neurodegenerative disease. Cytokines mediate many of these interactions in injury and disease, and they may also play key roles in the developing and normal adult brain. Experiments using mice with targeted mutations in the gene for one of these cytokines, leukemia inhibitory factor (LIF), demonstrate that this protein is required for appropriate cell and behavioral responses to trauma in the nervous system. We find that LIF is induced by physical injury or chemically-induced inflammation, and in the absence of this cytokine, neuronal, astrocytic, microglial, neutrophil, macrophage and pain responses to these insults are strikingly altered. The specific effects of LIF deficiency depend critically on the site and type of injury, however. The inflammatory response can also be important in the establishment and/or progression of neurodegenerative disease. To study this we are using a transgenic mouse model of Alzheimer’s disease (AD). Preliminary results indicate that stressing the animals can strongly up-regulate the microglial reaction around senile plaques