Search results for "MECHANISMS"
showing 10 items of 587 documents
Female Attraction Behaviour of Radio Tagged Polyterritorial Pied Flycatcher Males
1993
AbstractPolygynous mating is costly for pied flycatcher (Ficedula hypoleuca) females. Thus, females have a good reason to attempt to avoid mating with already mated polyterritorial males. One cue to disclose a male's mating status is his behaviour. The behaviour of polyterritorial and unmated males was studied by radio tagging that allows accurate recording of male movements. While attracting a secondary female polyterritorial males spent significantly less time on the secondary territory than did unmated males on their single territory. Polyterritorial males also tended to have lower song rates. When a female appeared on the secondary territory of polyterritorial males, they increased the …
Agonistic and sociable behaviors in the mound-building mice,Mus spicilegus: A comparative study withMus musculus domesticus
2001
Present social organization and mating systems result from selective pressures and ecological conditions but also from proximate interactions between individuals. Many studies report on a polygynous mating system with a social group territoriality in commensal populations of Mus musculus domesticus. However, little is known about the social organization of other Mus species living in outdoor conditions, such as the mound-building mouse Mus spicilegus. Comparative studies between M. m. domesticus and M. spicilegus have already shown behavioral differences in female sexual preferences and paternal care. To study agonistic and sociable interactions and gain insight into the social organization…
Cowbird versus cuckoo hosts: a comparative study of learned nest defense
2005
One of the best example of coevolutionaru adaptations is that of the interactions between avian brood parasites and their hosts. Brood parasites lay their eggs in nests of other specieis and leave the job of caring for their young with the hosts. Hosts of brood parasites tend to suffer high reproductive costs as often they raise few of no young of their own, an effect of being parasitizes. For this reason, many hosts have evolved strategies that reduces the cost of parasitism.
The image of the smoking and non-smoking young person
1985
MORE than 1,600 Finnish secondary school pupils between the ages of 12 and 16 completed a question naire about their image of the smoking and non- smoking adolescent. A smoker was described as nervous, unfriendly, untidy, stupid and a low achiever in sport and academic work, but despite this, was seen as a leader. Non-smokers were seen as calm, strong, fairly modest, friendly, tidy and smart, but not as leaders. Older pupils saw the smoker in a more positive light. Those who smoked saw the non- smoker image as positive, and rated the smoking image more highly than did non smokers.
An exploration of anger phenomenology in multiple sclerosis
2009
Background and purpose: Multiple sclerosis (MS) patients are often emotionally disturbed. We investigated anger in these patients in relation to demographic, clinical, and mood characteristics. Patients and methods: About 195 cognitively unimpaired MS patients (150 relapsing–remitting and 45 progressive) were evaluated with the State Trait Anger Expression Inventory, the Chicago Multiscale Depression Inventory, and the State Trait Anxiety Inventory. The patients’ anger score distribution was compared with that of the normal Italian population. Correlation coefficients among scale scores were calculated and mean anger scores were compared across different groups of patients by analysis of …
A DFT study of the molecular mechanisms of the nucleophilic addition of ester-derived lithium enolates and silyl ketene acetals to nitrones: Effects …
2006
9 pages, 6 schemes, 3 figures, 2 tables.
Electrosynthesis as a powerful method for the generation of catalytic intermediates: efficient isolation of a palladium aryl halide oxidative additio…
2011
International audience; Polyphosphane ligands of controlled conformation promote highly efficient palladium-catalyzed cross-coupling reactions. Electrosynthesis has been used as a new straightforward method to obtain important intermediates in the search for a better mechanistic understanding. As a proof of concept, the facile synthesis of a phenyl iodopalladium(II) complex (2) was conducted at the electrolysis scale from a readily electrogenerated unstable Pd0 precursor.
Overview on oxidation mechanisms of organic compounds by TiO2 in heterogeneous photocatalysis
2012
This review provides the reader with a general overview on heterogeneous photocatalytic oxidation mechanisms in the presence of TiO2, with a special address to conversion of aliphatic and aromatic organic species. The aim was to clarify the steps of the photo-oxidation of the various classes of compounds and to relate them with the properties of the catalysts and the experimental conditions used. Reactions carried out to perform complete degradation and photocatalytic partial oxidations have been deeply discussed. Recent isotopic studies highlighted new reaction pathways concerning partial oxidation of alcohols to aldehyde and oxidation of benzene while EPR investigations confirmed that not…
Novel Sortase A Inhibitors to Counteract Gram-Positive Bacterial Biofilms
2019
Sortase A (SrtA) is a membrane enzyme responsible for the covalent anchoring of surface proteins on the cell wall of Gram-positive bacteria. Nowadays it is considered an interesting target for the development of new anti-infective drugs which aim to interfere with important Gram-positive virulence mechanisms. Along the years, we studied the anti-staphylococcal and anti-biofilm activity of some natural and synthetic polyhalogenated pyrrolic compounds, called pyrrolomycins. Some of them were active on Gram-positive pathogens at a μg/mL range of concentration (1.5-0.045 μg/mL) and showed a biofilm inhibition in the range of 50-80%. [1-3] In light of these encouraging results, herein we present…
The hedgehog receptor patched is involved in cholesterol transport.
2011
International audience; BACKGROUND: Sonic hedgehog (Shh) signaling plays a crucial role in growth and patterning during embryonic development, and also in stem cell maintenance and tissue regeneration in adults. Aberrant Shh pathway activation is involved in the development of many tumors, and one of the most affected Shh signaling steps found in these tumors is the regulation of the signaling receptor Smoothened by the Shh receptor Patched. In the present work, we investigated Patched activity and the mechanism by which Patched inhibits Smoothened. METHODOLOGY/PRINCIPAL FINDINGS: Using the well-known Shh-responding cell line of mouse fibroblasts NIH 3T3, we first observed that enhancement …