7,107 research outputs found
MOLECULAR CHARACTERISATION OF Burkholderia pseudomallei
A programme of research was carried out to attempt the molecular characterisation of the human and
animal pathogen, Burkholderia pseudomallei, the causative agent of melioidosis and the newly
described avirulent species, B.thailandensis for comparative purposes. Melioidosis is still little
understood, and so the clinical approach to the prevention and control of melioidosis must ultimately
rest upon the basic understanding of the causative organism, particularly the pathogenic properties of
B.pseudomallei.
A range of B.pseudomallei and B.thailandensis isolates were cultured and the extracellular products
were isolated and concentrated and an initial study conducted to identify potential target molecules for
cloning. Those isolates tested were shown to have somewhat differing ECP profiles when analysed
with SDS-PAGE and antigenic profiles when subject to irnmunoblotting using convalescent human
serum although isolates within and between species shared a number of common bands. The ECPs
were also tested for a range of activities and it was established that both species had proteolytic and
phospholipase activities neither had a haemolytic activity and only isolates of B.pseudomallei had a
hexosaminidase activity a putative pathogenicity determinant.
Genomic DNA of B.pseudomallei was used to construct genomic libraries in a range of E. coli host
vector systems. A λGTII genomic library was screened with antisera for the presence of
B.pseudomallei antigens and a number of natural and synthetic substrates for the presence of
haemolytic and proteolytic components. Screening yielded one stable immunopositive clone with a
novel positive reaction in the form of a "halo" of reaction around the plaque. The 5 kbp cloned
fragment was subcloned into a plasmid vector, and the resulting recombinant molecule, pBPGT2 was
DNA sequenced and found to contain a putative pilin gene. Attempts were made to determine the size
of the recombinant antigen and to further express the pilin gene product all of which were
unsuccessful. A southern blot procedure confirmed the fidelity of the cloning procedure proving that
the fragment was from the host organism, B.pseudomallei. A further southern blot procedure tested for
the presence of the pilin sequence in a range of B.pseudomallei and B.thailandensis isolates proving
the presence of the gene in only isolates of B.pseudomallei.
PCR primers were designed to amplify the DNA encoding the active site of the ADP-ribosylating
toxin (ET A) of Pseudomonas aeruginosa and a PCR reaction was carried out on a number of
B.pseudomallei and B.thailandensis isolates. The reaction yielded a 500 bp product in only
B.pseudomallei isolates and DNA sequencing of the product revealed no obvious homology to ETA of
P.aeruginosa but was used as a probe to isolate a larger fragment of DNA which was found to encode
a number of interesting putative genes. These included one with homology to a porin similar to that of
the pathogen Neisseria gonorrhoea, with a role in virulence.
During attempts to digest the genomic DNA of B.pseudomallei isolate 4845 with the restriction
enzyme Sau3A two 12 kbp bands of DNA were resistant to the endonuclease activity. Attempts were
made to clone these bands into a range of plasmid vectors with two clones containing deleted products.
DNA sequencing proved inadequate with only a small amount of sequence information obtained.
However, towards the final stages of the research project sequence information from the
B.pseudomallei genome sequencing project facilitated the recognition of a 38 kbp fragment containing
the sequence information from one of the clones, which encodes an alkaline protease and a putative
haemagglutinin and is postulated to be a Pathogenicity Island encoding secreted virulence factors.
The sequencing project also facilitated the isolation of two putative hexosaminidase genes postulated
to be responsible for the activities observed when testing the B.pseudomallei isolates concentrated
ECPs. Future studies for the putative genes identified and other components of B.pseudomallei are
discussed.D.E.R.A. PORTON DOW
All That's Fit: Nationalist Struggle and Early Photojournalism in Egypt
Conference paper presented March 25-26, 2011.This paper explores the ambiguous function of state-controlled public
photojournalistic archives in Egypt just prior to the popular uprisings
that began on January 25, 2011. In this context, the archive persisted
as an uneasy site of memory under the auspices of a thirty-year regime
that insisted on its own ahistoricity, instead deploying images of
historic events and personages towards self-mythologizing ends. My
research focused originally on the development of early photojournalism
in conjunction with the emergence of anti-colonial and nationalist
struggle in Egypt, and photojournalism's role in producing and
disseminating images of the nation prior to 1952. Despite limiting the
scope of this research to photographs already approved by censors for
public consumption through publication, gaining access to longstanding
photojournalistic archives at the periodical publishing houses of Al
Ahram and Dar al Hilal in Cairo presented many obstacles. I address the
generative role of erasure and obfuscation in the production of the
photojournalistic image and its archive both in relation to this
problematic of access encountered over the course of a research process
undertaken in the summer of 2010, and the images of a nation encountered
in those photographs dating to between c. 1919-1952, which I was
ultimately able to examine.Research sponsored by the Samuel H. Kress Foundation, summer 2010.
Conference supported by the Samuel H. Kress Foundation, the NYU
Humanities Initiative, the IFA Visual Resources Collections, and
Princeton University, Department of Art and Archaeology, Visual
Resources Collection
Cognitive aspects of work with digital maps
Digital maps of geographic areas are increasingly common in many types of
workplace, in education and in the public domain. Their interactivity and visual
features, and the complexity of geographic(al) information systems (GIS) which
create, edit and manipulate them, create special cognitive demands on the end-user
which are not present in traditional cartographic maps or in most human-computer
interaction (HCI). This thesis reviews cross-disciplinary literature regarding cognitive
aspects of viewing and interacting with digital maps.
Data from an observational study of GIS use, including real-time recordings of
normal workplace activities, was analysed using various approaches to examine the
interactive and visual aspects of people's work. The implications for cartographic,
psychological and HeI aspects of GIS are discussed, in the context of the actual tasks
people perform with them (rather than the computationally advanced analyses
assumed by most literature).
The second phase of the research examined the spatial knowledge attained and used
during this interaction. The relevance of specific concepts in cognitive psychology,
and of factors that create individual differences in cognition, are discussed in depth,
alongside work in environmental and educational psychology, cartography and
geography.
A controlled experiment examined the degree to which task characteristics induce a
different spatial model or reference frame when viewing a digital map. It was shown
that even novice users can switch between considering the map as an abstract
geometric display or as a geographical representation, without affecting performance.
However, tasks forcing subjects to focus entirely on the geometry rather than the
geography did affect performance in a surprise post-test photograph identification
task. Map users' mental model or reference frame is apparently affected by these task
constraints; this has implications for GIS design and practice as well as for
understanding spatial cognition The study also considered the role of expertise and
other individual difference factors, although conclusions were limited by sample size.
Further research issues are highlighted, particularly regarding the knowledge
structures and spatial language used in interpreting digital maps
Evaluating complex digital resources
Squires (1999) discussed the gap between HCI (Human Computer Interaction) and the educational computing communities in their very different approaches to evaluating educational software. This paper revisits that issue in the context of evaluating digital resources, focusing on two approaches to evaluation: an HCI and an educational perspective. Squires and Preece's HCI evaluation model is a predictive model ‐ it helps teachers decide whether or not to use educational software ‐ whilst our own concern is in evaluating the use of learning technologies. It is suggested that in part the different approaches of the two communities relate to the different focus that each takes: in HCI the focus is typically on development and hence usability, whilst in education the concern is with the learner and teacher use
Overlooked examples of cloud self-organization at the mesoscale
Stratocumulus clouds are common in the tropical and subtropical marine boundary layer, and understanding these clouds is important due to their significant impact on the earth's radiation budget. Observations show that the marine boundary layer contains complex, but poorly understood processes, which, from time to time, result in the observable self-organization of cloud structures at scales ranging from a few to a few thousand kilometers. Such shallow convective cloud features, typically observed as hexagonal cells, are known generally as mesoscale cellular convection (MCC). Actinoform clouds are rarer, but visually more striking forms of MCC, which possess a radial structure.
Because mesoscale cloud features are typically too large to be observed from the ground, observations of hexagonal cells historically date only to the beginning of satellite meteorology. Examples of actinoform clouds were shown in the venerable “Picture of the Month” series in Monthly Weather Review in the early 1960s, but these clouds were generally forgotten as research focused on hexagonal cells.
Recent high-resolution satellite images have, in a sense, “rediscovered” actinoform clouds, and they appear to be much more prevalent than had been previously suspected. We show a number of examples of actinoform clouds from a variety of locations worldwide. In addition, we have conducted a detailed case study of an actinoform cloud system using data from the Multiangle Imaging SpectroRadiometer (MISR) and the Geostationary Operational Environmental Satellite (GOES), including analysis of cloud heights, radiative properties, and the time-evolution of the cloud system. We also examine earlier theories regarding actinoform clouds in light of the new satellite data
An audit of the compliance of Harrogate district hospital's current post vasectomy clearance service
Feeding infants: choice-specific considerations, parental obligation, and pragmatic satisficing
Health institutions recommend that young infants be exclusively breastfed on demand, and it is widely held that parents who can breastfeed have an obligation to do so. This has been challenged in recent philosophical work, especially by Fiona Woollard. Woollard’s work critically engages with two distinct views of parental obligation that might ground such an obligation—based on maximal benefit and avoidance of significant harm—to reject an obligation to breastfeed. While agreeing with Woollard’s substantive conclusion, this paper (drawing on philosophical discussion of the ‘right to rear’) argues that there are several more moderate views of parental obligation which might also be thought to ground parental obligation. We first show that an obligation to breastfeed might result not from a general obligation to maximally benefit one’s child, but from what we call ‘choice-specific’ obligations to maximise benefit within particular activities. We then develop this idea through two views of parental obligation—the Dual Interest view, and the Best Custodian view—to ground an obligation to exclusively breastfeed on demand, before showing how both these more moderate views fail. Finally, we argue that not only is there no general obligation to breastfeed children, but that it is often morally right not to do so. Since much advice from health institutions on this issue implies that exclusive breastfeeding on demand is the best option for all families, our argument drives the feeding debate forward by showing that this advice often misrepresents parents’ moral obligations in potentially harmful ways
WHO runs the world – (not) girls: gender neglect during global health emergencies
During health emergencies, neglect of gender experiences and needs can compromise the outbreak response. Ebola in West Africa and Zika in Latin America had gendered effects that were evident during the crises, yet governments and international organisations failed to prioritise a gender inclusive response. There is the same risk of neglecting gender inclusive response and knowledge during COVID-19. In this article we examine the consequence of gender exclusion in health emergency response. We ask where can we locate institutional responsibility to take gender seriously to inform and improve sustainable disease control? This article seeks to address this question by turning to feminist institutional theory to explain why gender inclusion in decision making processes is vital for effective response and post-crisis recovery. We argue that the institutional responsibility to recognise gender within the global health emergency regime lies with World Health Organization (WHO). WHO has neglected to mainstream gender into the policies and practice which they promote for the prevention, detection and response of infectious disease outbreaks. WHO is in a position to support gender inclusion practices but it requires the technical agency to recognise the value of gender inclusion framework to inform outbreak response, financial models, and recovery
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