951 resultados para Baert, Francois, 1651-1719
Resumo:
Although there is currently no evidence of emerging strains of measles virus (MV) that can resist neutralization by the anti-MV antibodies present in vaccinees, certain mutations in circulating wt MV strains appear to reduce the efficacy of these antibodies. Moreover, it has been hypothesized that resistance to neutralization by such antibodies could allow MV to persist. In this study, we use a novel in vitro system to determine the molecular basis of MV's resistance to neutralization. We find that both wild-type and laboratory strain MV variants that escape neutralization by anti-MV polyclonal sera possess multiple mutations in their H, F, and M proteins. Cytometric analysis of cells expressing viral escape mutants possessing minimal mutations and their plasmid-expressed H, F, and M proteins indicates that immune resistance is due to particular mutations that can occur in any of these three proteins that affect at distance, rather than directly, the native conformation of the MV-H globular head and hence its epitopes. A high percentage of the escape mutants contain mutations found in cases of Subacute Sclerosing Panencephalitis (SSPE) and our results could potentially shed light on the pathogenesis of this rare fatal disease.
Resumo:
Defects in primary cilium biogenesis underlie the ciliopathies, a growing group of genetic disorders. We describe a whole-genome siRNA-based reverse genetics screen for defects in biogenesis and/or maintenance of the primary cilium, obtaining a global resource. We identify 112 candidate ciliogenesis and ciliopathy genes, including 44 components of the ubiquitin-proteasome system, 12 G-protein-coupled receptors, and 3 pre-mRNA processing factors (PRPF6, PRPF8 and PRPF31) mutated in autosomal dominant retinitis pigmentosa. The PRPFs localize to the connecting cilium, and PRPF8- and PRPF31-mutated cells have ciliary defects. Combining the screen with exome sequencing data identified recessive mutations in PIBF1, also known as CEP90, and C21orf2, also known as LRRC76, as causes of the ciliopathies Joubert and Jeune syndromes. Biochemical approaches place C21orf2 within key ciliopathy-associated protein modules, offering an explanation for the skeletal and retinal involvement observed in individuals with C21orf2 variants. Our global, unbiased approaches provide insights into ciliogenesis complexity and identify roles for unanticipated pathways in human genetic disease.
Resumo:
OBJECTIVES: To demonstrate how individual participant data (IPD) meta-analyses have impacted directly on the design and conduct of trials and highlight other advantages IPD might offer.
STUDY DESIGN AND SETTING: Potential examples of the impact of IPD meta-analyses on trials were identified at an international workshop, attended by individuals with experience in the conduct of IPD meta-analyses and knowledge of trials in their respective clinical areas. Experts in the field who did not attend were asked to provide any further examples. We then examined relevant trial protocols, publications, and Web sites to verify the impacts of the IPD meta-analyses. A subgroup of workshop attendees sought further examples and identified other aspects of trial design and conduct that may inform IPD meta-analyses.
RESULTS: We identified 52 examples of IPD meta-analyses thought to have had a direct impact on the design or conduct of trials. After screening relevant trial protocols and publications, we identified 28 instances where IPD meta-analyses had clearly impacted on trials. They have influenced the selection of comparators and participants, sample size calculations, analysis and interpretation of subsequent trials, and the conduct and analysis of ongoing trials, sometimes in ways that would not possible with systematic reviews of aggregate data. We identified additional potential ways that IPD meta-analyses could be used to influence trials.
CONCLUSIONS: IPD meta-analysis could be better used to inform the design, conduct, analysis, and interpretation of trials.
Resumo:
As modern power grids move towards becoming a smart grid, there is an increasing reliance on the data that is transmitted and processed by ICT systems. This reliance introduces new digital attack vectors. Many of the proposed approaches that aim to address this problem largely focus on applying well-known ICT security solutions. However, what is needed are approaches that meet the complex concerns of the smart grid as a cyber-physical system. Furthermore, to support the automatic control loops that exist in a power grid, similarly automatic security and resilience mechanisms are needed that rely on minimal operator intervention. The research proposed in this paper aims to develop a framework that ensures resilient smart grid operation in light of successful cyber-attacks.
Resumo:
We present photometric and spectroscopic observations of the interacting transient SN 2009ip taken during the 2013 and 2014 observing seasons. We characterize the photometric evolution as a steady and smooth decline in all bands, with a decline rate that is slower than expected for a solely Co-56-powered supernova at late phases. No further outbursts or eruptions were seen over a two year period from 2012 December until 2014 December. SN 2009ip remains brighter than its historic minimum from pre-discovery images. Spectroscopically, SN 2009ip continues to be dominated by strong, narrow (less than or similar to 2000 km s(-1)) emission lines of H, He, Ca, and Fe. While we make tenuous detections of [Fe II] lambda 7155 and [O I] lambda lambda 6300, 6364 lines at the end of 2013 June and the start of 2013 October, respectively, we see no strong broad nebular emission lines that could point to a core-collapse origin. In general, the lines appear relatively symmetric, with the exception of our final spectrum in 2014 May, when we observe the appearance of a redshifted shoulder of emission at +550 km s(-1). The lines are not blueshifted, and we see no significant near-or mid-infrared excess. From the spectroscopic and photometric evolution of SN 2009ip until 820 d after the start of the 2012a event, we still see no conclusive evidence for core-collapse, although whether any such signs could be masked by ongoing interaction is unclear.
Resumo:
Where either the seller or buyer of landed property fails to complete a contract to sell land the non-breaching party has a right to seek specific performance of the contract. This remedy would compel the party in default to perform the contract on pain of being held in contempt of court if the court's order is not obeyed. The defaulting party would not be able to satisfy its obligations under the law by paying a sum of money as damages for breach of contract. This paper considers the impecuniosity defence to specific performance as recognised by courts in Northern Ireland, the Republic of Ireland, Australia and New Zealand. Where the buyer demonstrates that he or she simply cannot raise the funds to buy the property specific performance will not be decreed and the court will make an award of damages for breach of contract measured by the difference between the contract price and the market price of the property at the time of default. The paper considers the nature and parameters of this defence and how it differs (if at all) from the alternative defence of extreme hardship. The paper addresses the question of whether it might be better to move to a position where sellers of land in all cases no longer enjoy a presumption of specific performance but have to demonstrate that the alternative remedy of damages is clearly inadequate. If this should be so the paper goes on to consider whether abolition of the presumption in favour of specific performance for sellers should lead to abolition of the presumption of specific performance for buyers, as is the position in Canada following the Supreme Court's decision in Semelhago v Paramadevan [1996] 2 SCR 415.
Resumo:
This study is about the troubles encountered by one researcher in getting qualitative research on partnerships between families, in disadvantaged situations and educators in toddler day care settings and how they affect the quality of care as perceived by parents and educators. The study focuses on the conflicts and tensions as perceived by families and educators. A secondary goal of the study is to develop a greater understanding of how day care training programs might incorporate the findings to prepare day care educators to work with families in disadvantaged circumstances. The study is done through a qualitative lens using an ecological framework. The study spans a three month period and is set up in a non-profit, parent-controlled day care center. Detailed 'narratives of experience' are constructed from the participants' reflections on the events. Three main barriers or conflicts have emerged from the study. They are time, fear and a difference in perceptions between the families and the educators. The thesis concludes with advice to researchers who may be contemplating setting up a similar study and some suggestions are proposed for day care training programs. These suggestions include reflections of the researcher and how she implemented changes in her own teaching.
Resumo:
Corpo errático e volátil por excelência, a anedota constitui porventura o género do discurso através do qual uma comunidade (conceito, como se sabe, cada vez mais alargado) mais dinâmica e prontamente comenta os sentidos dos múltiplos fenómenos –éticos, culturais, filosóficos, pragmáticos, etc.– com que a cada passo se confronta e (re)constrói. Operando, antes de mais, em termos de uma concepção lúdica da vida, a anedota distende-se por múltiplas e versáteis conformações de natureza tipológica, tropológica e topológica.
Resumo:
The literatures on both authentic leadership and behavioral integrity have argued that leader integrity drives follower performance. Yet, despite overlap in conceptualization and mechanisms, no research has investigated how authentic leadership and behavioral integrity relate to one another in driving follower performance. In this study, we propose and test the notion that authentic leadership behavior is an antecedent to perceptions of leader behavioral integrity, which in turn affects follower affective organizational commitment and follower work role performance. Analysis of a survey of 49 teams in the service industry supports the proposition that authentic leadership is related to follower affective organizational commitment, fully mediated through leader behavioral integrity. Next, we found that authentic leadership and leader behavioral integrity are related to follower work role performance, fully mediated through follower affective organizational commitment. These relationships hold when controlling for ethical organizational culture.
Resumo:
Total pollen production per inflorescence was studied in the most important species of the Poaceae family in the city of Córdoba in order to further our knowledge of the partial contribution of each species of this family to the total amount of pollen released into the atmosphere. The contribution of grasses in a given area was estimated by counting the number of inflorescences in an area of one square meter. Four different representative areas of the city were selected. The number of pollen grains per anther and flowers per inflorescence was also estimated in order to obtain total pollen production per inflorescence. Pollen production per inflorescence ranged from 14,500 to more than 22,000,000 pollen grains, the amount being clearly higher in the perennial species. Pollen production per square meter was higher in the mountains near the city and lower in areas of abandoned crops. Only a few species are responsible for the majority of pollen produced. A phenological study is necessary in order to determine the temporal distribution of this pollen production and subsequent shedding.
Resumo:
In the present study, a novel enzyme-based methodology for grafting Polyhydroxyalkanoates (PHAs) onto the ethyl cellulose (EC) as a backbone polymer was developed. Laccase assisted copolymerization was carried out under mild and eco-friendly reaction conditions. The resulting homogeneous composite membranes were characterized by Fourier-transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Atomic Force Microscopy (AFM). The FTIR spectra of pure PHAs and PHAs containing graft composites (PHAs-g-EC) showed their strong characteristic bands at 1721 cm1, 1651 cm-1 and 1603 cm-1 respectively. Other accompanying bands in the range of 900-1300 cm-1 correspond to C=O vibration and C-O-C bond stretching, which could be contributed from PHAs and EC, respectively. The high intensity of the 3358 cm-1 band in the graft composite may have corresponded to the degradation of the carboxylic group from PHAs and also showed an increase of hydrogen-bonded groups at that distinct band region. The morphology was examined by SEM, which showed the well dispersed PHAs crystals in the backbone polymer of EC. XRD pattern for PHAs showed distinct peaks at 2-Theta values of 28o, 32o, 34o, 39o, 46o, 57o, 64o, 78o and 84o that represent the crystalline nature of PHAs. In comparison with those of neat PHAs, the degree of crystallinity for PHAs-g-EC decreased and this reduction is mainly because of the new cross-linking of PHAs within the EC backbone that changes the morphology and destroys the crystallites. Improved mechanical properties were observed for the PHAs-g-EC as compared to the individual components due to the impregnation of EC as reinforcement into the PHAs matrix. Improved mechanical strength enhanced thermal properties, along with low crystallinity of the present PHAs-g-EC suggesting its potential for various industrial and bio-medical applications.
Resumo:
It is difficult to get the decision about an opinion after many users get the meeting in same place. It used to spend too much time in order to find solve some problem because of the various opinions of each other. TAmI (Group Decision Making Toolkit) is the System to Group Decision in Ambient Intelligence [1]. This program was composed with IGATA [2], WebMeeting and the related Database system. But, because it is sent without any encryption in IP / Password, it can be opened to attacker. They can use the IP / Password to the bad purpose. As the result, although they make the wrong result, the joined member can’t know them. Therefore, in this paper, we studied the applying method of user’s authentication into TAmI.