Search results for "Adaptive"
showing 10 items of 792 documents
An efficient adaptive strategy for searching in peer-to-peer networks
2005
One of the main technical challenges in Peer-to-Peer (P2P) networks is how to efficiently locate desired resources. Although structured systems, based on distributed hash tables, can achieve fair effectiveness, they are not suitable for widely deployed Internet applications. In fact, this kind of systems shows many severe limitations, such as ignoring the autonomous nature of peers, and supporting only weakly semantic functions. Unstructured P2P networks are more attractive for real applications, since they can avoid both the limitations of centralized systems, and the drawbacks of structured approaches. However, their search algorithms are usually based on inefficient flooding schemes, tha…
1653 – The developemnt of adaptive and maladaptive patterns of internet use among european adolescents at risk for internet addictive behaviors: a gr…
2013
Introduction Full findings from the European Commission funded EU-NET-ADB study (Safer Internet Programme) will be presented. Objectives Empirical findings that elucidate the development of an internet addictive behaviour are still incomplete. This is also related to risk as well as protective factors of internet use. Here a process oriented approach to identify underlying conditions of an internet addictive behaviour was chosen. Aims The aim of the study is to enhance the knowledge and understanding of underlying processes which lead to situation were internet addictive behaviour can evolve. Methods In total 124 in-depth interviews were conducted with adolescents with an age of 14-17 year.…
Birds facing climate change: a qualitative model for the adaptive potential of migratory behaviour
2015
Recent climate change is altering the migratory behaviour of many bird species. An advancement in the timing of spring events and a shift in the geographical distribution have been detected for birds around the world. In particular, intra-Palearctic migratory birds have advanced arrivals in spring and shortened migratory distances by shifting northward their wintering grounds. These changes in migratory patterns are considered adaptive responses facilitating the adjustment of the life cycle to the phenological changes found in their breeding areas. However, in some cases, populations exposed to the same selective pressures do not show any appreciable adaptive change in their behaviour. Basi…
Does predation maintain eyespot plasticity in Bicyclus anynana?
2004
The butterfly Bicyclus anynana exhibits phenotypic plasticity involving the wet-season phenotype, which possesses marginal eyespots on the ventral surface of the wings, and the dry-season form, which lacks these eyespots. We examined the adaptive value of phenotypic plasticity of B. anynana in relation to the defence mechanisms of crypsis and deflection. We assessed the visibility differences between spotless and spotted butterflies against backgrounds of brown (dry season) or green (wet season) leaves. Spotless butterflies were highly cryptic and less predated by adult bird predators than were spotted ones when presented against brown leaf litter. However, the advantage of crypsis disappea…
Maternal transfer of antibodies: raising immuno-ecology issues.
2007
The transfer of antibodies from mother to offspring has broad potential implications in evolutionary ecology, from the adaptive value of maternal effects to the role of transgenerational plasticity in host-parasite interactions. Recent contributions have addressed key issues such as environmental and genetic factors affecting the amount of antibodies transferred and whether maternal antibodies affect offspring immunity, but little is still known about the implications of the maternal transfer of antibodies in natural populations. By its position at the crossroads between population ecology, animal science, medicine and epidemiology, current studies of the role of the maternal transfer of an…
Optimization design process of a morphing winglet
2018
Aeronautic and aerospace engineering is recently moving in the direction of developing morphing wing devices, with the aim of making adaptable the aerodynamic shapes to different operational conditions. Those devices may be classified according to two different conceptual architectures: kinematic or compliant systems. Both of them embed within their body all the active components (actuators and sensors), necessary to their operations. In the first case, the geometry variation is achieved through an augmented classical mechanism, while in the second case the form modification is due to a special arrangement of the inner structure creating a distributed elastic hinges arrangement. Whatever is…
Natural and adoptive T-cell immunity against herpes family viruses after allogeneic hematopoietic stem cell transplantation.
2011
Reactivated infections with herpes family-related cytomegalovirus, Epstein–Barr virus and varicella zoster virus are serious and sometimes life-threatening complications for patients undergoing allogeneic hematopoietic stem cell transplantation. The pathogenesis of these infections critically involves the slow and inefficient recovery of antiviral T-cell immunity after transplantation. Although efficient drugs to decrease viral load during this vulnerable period have been developed, long-term control of herpes viruses and protection from associated diseases require the sufficient reconstitution of virus-specific memory T cells. To heal the deficiency by immunotherapeutic means, numerous re…
P and R Wave Detection in Complete Congenital Atrioventricular Block
2009
Complete atrioventricular block (type III AVB) is characterized by an absence of P wave transmission to ventricles. This implies that QRS complexes are generated in an autonomous way and are not coordinated with P waves. This work introduces a new algorithm for the detection of P waves for this type of pathology using non-invasive electrocardiographic surface leads. The proposed algorithm is divided into three stages. In the first stage, the R waves located by a QRS detector are used to generate the RR series and time references for the other stages of the algorithm. In the second stage, the ventricular activity (QT segment) is removed by using an adaptive filter that obtains an averaged pa…
Visual performance of the Akreos Adapt AO intraocular lens in patients with different corneal profiles measured with an adaptive optics visual simula…
2012
AIMS: To evaluate the visual performance of an aberration-free intraocular lens (IOL) in patients with different corneal profiles using adaptive optics visual simulation. METHODS: A crx1 adaptive optics visual simulator was used to simulate the aberration pattern of an aberration-free IOL combined with five corneal profiles: virgin corneas and corneas with low and high myopic ablations and low and high hyperopic ablations. Ten eyes of 10 subjects were evaluated, and monocular distance visual acuity (VA) at 100%, 50% and 10% of contrast was measured. RESULTS: At 100% of contrast, no differences were found in VA values among virgin corneas, low and high myopic ablations and low hyperopic abla…
Visual simulation through an aspheric aberration-correcting intraocular lens in subjects with different corneal profiles using adaptive optics.
2013
The aim of this study was to analyse the visual quality of the AcrySof IQ SN60WF® intraocular lens (IOL) when combined with different corneal profiles. Ten eyes of 10 participants with no prior history of refractive or cataract surgery were evaluated. An adaptive optics visual simulator was used to simulate the wavefront aberration pattern of an aspheric aberration-correcting IOL (AcrySof IQ SN60WF®). Normal corneas (group A), low and high myopic corneal ablations (groups B and C, respectively) and low and high hyperopic corneal ablations (groups D and E, respectively) were also simulated. Monocular distance visual acuities at 100, 50 and 10 per cent of contrast were measured. At 100, 50 an…