1,721,751 research outputs found
El conocimiento global : un reto para las bibliotecas
Full text linkThe benefits of the knowledge society can be realized for the disadvantaged. Information and communication technologies have the potential to support sustainable development. Huge infrastructure investments and access initiatives mean that the majority of the world’s population will have telecommunications access in the next 1015 years. But developing skills and content will be the biggest challenge, and there is real risk of perpetuating the ‘digital divide’. The G8 Okinawa Charter on the Global Information Society (2000) and the Global Knowledge Partnership promote initiatives to bridge the digital divide. The library and information profession can make a critical contribution, by providing access, structuring knowledge, imparting information skills, preserving heritage and inspiring trust. But a public relations campaign is needed to raise awareness of what the profession can offer, and to win it a voice in the digital divide debate.
Translation of “Global Knowledge: a Challenge for Librarians”, Edwards, Christopher, in IFLA Journal, Vol. 27, No. 2 (2001), pp. 65-69. Translated by LOZANO PALACIOS, A, with the collaboration of the students of the Faculty of Library and Information Science, University of Granada
Statement of facts, Monroe Edwards, Christopher Dart 1841
No full textStatement of facts, Monroe Edwards, Christopher Dart 184
Radiation hard CMOS circuits in isolated substrate technology for analogue to digital conversion
No full textThe application of high performance integrated circuits in military and space environments imposes a requirement to withstand the effects of exposure to ionising radiation. In such applications, dielectrically isolated CMOS technologies present significant performance advantages over other technologies by virtue of the insulated gate MOS structure, immunity to single event latch-up phenomena, and a reduced volume of active silicon for photocurrent generation. For many digital signal processing systems operating in these environments, there is the need for some radiation-tolerant analogue front-end signal interface in the form of analogue-to-digital conversion. This thesis demonstrates the application of analogue circuit design techniques for achieving high total dose radiation-hardness in analogue-to-digital converter (ADC) systems, fabricated in isolated substrate CMOS technology intended for radiation hard digital applications.In undertaking such experimental circuit design, a stable fabrication process is important. With this in mind the GEC Plessey (now Mitel) Semiconductors (Lincoln) silicon-on-sapphire (SOS) process was used due to the availability of process data concerning both transistor parameters and radiation performance. The behavioural parallels between SOS and emerging silicon-on-insulator (SOI) processes will mean that the analysis of circuit behaviour in SOS will be mostly applicable to SOI.This study is in several parts. Isolated substrate CMOS is examined both in terms of its particular analogue performance and in relation to radiation effects. Basic circuit cells in SOS are evaluated for floating body behaviour and radiation performance. Particular emphasis is given to the stability of the operating point with respect to bias drift at critical nodes, where small relative variations can ruin circuit functionality. Having established behavioural models from circuit level simulations, the performance of certain well-known ADC architectures are examined at system level in terms of radiation effects, to show how degradation in performance varies between architectures. As a result of these studies, two radiation hard ADCs are designed and fabricated in the 1.5μm SOS process, namely a first order switched capacitor ΣΔ modulator with 4-bit internal quantiser, and a 7-bit FLASH ADC.</p
Can the events of early life influence the development of rheumatoid arthritis?
No full textI am often asked the same question by newly diagnosed patients, “Why me? Why did I get rheumatoid arthritis?” The easy response is to trot out an answer that both genes and environmental factors are important. However, it is difficult to provide detail to the sequence of events, and the relative importance of each, needed to induce the chronic inflammation of rheumatoid arthritis (RA).Genetic factors are clearly important. HLA-DRB1 alleles have repeatedly been shown to be associated with the development of RA. Genome-wide studies have also identified other genes both within and outside the major histocompatibility complex (MHC)1. In contrast, advances in our understanding of the role of the environment have often been slower and received less attention. Nevertheless, progress has been made. This is particularly true for exposure to tobacco smoke that has been shown in many studies to be a strong risk factor for the development of RA2. Smoking exposure is also a key example of the importance of interactions between genes and environment.Despite some success there are major challenges to studying the role of environmental factors in the etiology of RA. One of these is the fact that disease commonly starts in middle age. This allows the opportunity for many different exposures throughout life to have had an effect on disease development over many decades. It has become clear that immunological and inflammatory changes begin many years before the onset of joint pain and swelling. The autoantibodies rheumatoid factor (RF) and anti-cyclic citrullinated peptides (anti-CCP) and a raised C-reactive protein (CRP) are all detectable in serum years before symptoms begin3. This has led to the idea that a major block to unraveling the role of environmental factors in RA may be that we are “looking too late”4. Perhaps crucial environmental exposures are missed when we don’t look early enough. If this is true then is it biologically plausible that events during neonatal life and childhood could have lifelong effects?There is now a large body of evidence suggesting that early life events can lead to disease in later life. Work in this area, initially in relation to cardiovascular disease, led to the hypothesis of the “fetal origins of adult disease” proposed by David Barker5. The hypothesis proposes that early life development in adverse circumstances produces a “thrifty phenotype” that prepares the offspring for a more challenging environment. This in turn produces unintended adverse consequences later in life. An example of this is seen in the increased likelihood of hypertension in adults who had low birth weight6. Some of these effects may be mediated through a re-setting of hypothalamic-pituitary-adrenal (HPA) and growth hormone/insulin-like growth factor-1 (GH/IGF-1) axes. For example, low birth weight appears to result in the programming of the HPA axis to produce more cortisol7,8.Early life events may effect the development of autoimmune disease in 2 main ways. The first is through the effects of poor fetal and infant growth as described for low birth weight and hypertension and the second through early life exposure to exogenous factors including microorganisms. Early life growth has been shown to have effects on the development of autoimmune thyroid disease, with low birth weight being associated with increased thyroid autoimmunity9,10. In contrast, development of type I diabetes has been associated with higher weight at 6 months of age11.In this issue of The Journal Simard and colleagues have shown a lack of association between preterm birth or being breastfed and incident RA in women12. The study was carried out using a large number of individuals from the Nurses’ Health Study (NHS) and the Nurses’ Health Study II (NHSII). The same group has shown an association between high birth weight and a greater risk of developing adult RA in the NHS. Interestingly, they have also shown that higher birth weight was associated with an increased incidence of developing systemic lupus erythematosus in the same cohort13. Other groups have shown associations between high birth weight and development of RA14, and low birth weight being protective for the development of RA and juvenile idiopathic arthritis (JIA) (a nonsignificant trend)15. However, birth weight and infant growth have been shown to have no effect on the development of RF in adults16. In general, high birth weight seems to increase the likelihood of RA in later life. The new finding that preterm birth does not affect the likelihood of developing RA does not detract from this.The new results on breastfeeding are in contrast to previous findings that initiation of early breast feeding is associated with the development of RA14 and that HLA-DR4-negative individuals who are RF-positive are more likely to have been breastfed17. There are differences in the populations studied, and diverse results from different groups may also show the difficulty in studying these effects in RA. However, the most recent study contains the largest number of individuals and has the most detailed information on the degree of exposure to breastfeeding.One major difficulty with defining associations between environmental factors and a complex disease like RA is its heterogeneity. This may ultimately be addressed by exact phenotyping of patients into different disease subgroups. This subtyping is likely to increase the reliability of future studies including those looking at environmental factors. The importance of this approach has already been highlighted by studies showing that the effect of breastfeeding in the development of RF is dependent on the presence or absence of HLA-DR417.So does all this work help to answer the patient’s question as to why they developed RA? Well, maybe. It suggests that large babies are more likely to develop RA, that being preterm has no effect, and that if breastfeeding is important it is probably less so. Perhaps high birth weight results in the programming of the HPA axis to produce less cortisol and shifts the balance towards chronic inflammation
Intravenous pulses of methylprednisolone for systemic lupus erythematosus
No full textBackground: Intravenous (IV) pulses of methylprednisolone (MEP) commonly are used to treat severe manifestations of systemic lupus erythematosus (SLE). However, despite wide use of this treatment the best dose, timing, and the situations in which this treatment should be used remain largely anecdotal. Aim: To review the mechanisms of action and evidence for clinical use of IV MEP in the treatment of SLE.Method: The literature on MEP use in SLE from 1966 to 2002, using PubMed from the National Library of Medicine, was reviewed. Results: As with other modes of corticosteroid administration, IV MEP has significant anti-inflammatory and immunosuppressive actions. These actions have been shown to be effective in treating SLE in clinical trials, for lupus nephritis. The studies are mainly uncontrolled and retrospective. Long-term observations from a few double-blind prospective trials suggest that monthly pulses of MEP, in addition to IV cyclophosphamide, may be useful. Pulse MEP is beneficial for several serious manifestations of SLE, such as neuro-psychiatric lupus, pulmonary hemorrhage, severe blood dyscrasias, cardiomyopathy, and vasculitis. However, significant side effects may occur, mostly infections, which are worse in patients with hypoalbuminemia. Conclusion: IV pulses of MEP rapidly immunosuppress patients with organ and/or life-threatening manifestations of SLE. However, the gold standard 1 g/day for 3 consecutive days is associated with significant infectious complications and lower doses may be just as useful
Inflammation and dementia: Using rheumatoid arthritis as a model to develop treatments?
No full textDementia is a major international public health problem which looks set to grow as the ageing population increases. Despite large amounts of investment there has been relatively little progress in developing new therapies to combat this. There is a growing body of evidence that both local and systemic inflammation are important in dementia; with cerebral inflammation occurring secondarily to beta-amyloid plaques, raised levels of serum inflammatory molecules and cytokines being present in Alzheimer's disease patients and systemic inflammation being associated with cerebral microvasculature disease in vascular dementia. Observational studies had suggested that non-steroidal anti-inflammatory drugs may reduce the risk of dementia, but subsequent interventional studies have been disappointing. More recently some observational studies have suggested a protective effect from conventional synthetic disease modifying anti-rheumatic drugs (csDMARDS) and tumour necrosis factor inhibiting (TNFi) biological therapies. Treatments for inflammatory rheumatic diseases have previously been repurposed and used successfully in other diseases, such as TNFi for inflammatory bowel disease. There are also studies looking at the use of csDMARDs such as methotrexate to improve outcomes after cardiovascular events. Ongoing interventional trials are currently looking at whether therapies designed to treat inflammatory and autoimmune diseases have the potential to be used to treat dementia.</p
Sliding Mode Based Dynamic State Estimation for Synchronous Generators in Power Systems
Full text linkThis is the author accepted manuscript. The final version is available from IEEE via the DOI in this record This letter deals with the design of a robust sliding mode observer for dynamic state estimation applied to synchronous generators in power systems. Assuming only the frequency deviation of the generator is measured via phasor measurement units, we use a robust sliding mode estimation technique to dynamically reconstruct the rotor angle and the transient voltage. The adopted estimation technique is insensitive to matched bounded uncertainties affecting the dynamics of the synchronous generator. A stability analysis and tuning rules for the observer are also provided. Numerical simulations confirm the validity of the approach
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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