509 research outputs found
In the City
I curated In the City: Portraits from the City of London especially for the National Portrait Gallery. The intention was to place the unknown and unsung workers of London’s Square Mile alongside the familiar and famous corporate faces - striking a balance between the Gallery’s narrow institutional view of fame and celebrity and my own vision.
The portraits in the installation were extracted from a unique project - the largest photographic project of its kind carried out in the UK during the past 20 years.
In the City takes inspiration from People of the Twentieth Century by the German photographer August Sander and Irving Penn’s Small Trades series. The approach, using a 5x4 view camera, was uncompromising and formal, yet ‘subject sympathetic’ to reveal people in immaculate detail, regardless of their status.
There was insufficient space to display all 138 images from the project, so my role as curator was to ensure the “invisible” workforce were not lost in the selection process. Hence my insistence that the portrait of Von, the despatch rider, serve as an iconic image for all the publicity materials
Finding critical points using improved scaling Ansaetze
Analyzing in detail the first corrections to the scaling hypothesis, we
develop accelerated methods for the determination of critical points from
finite size data. The output of these procedures are sequences of
pseudo-critical points which rapidly converge towards the true critical points.
In fact more rapidly than previously existing methods like the Phenomenological
Renormalization Group approach. Our methods are valid in any spatial
dimensionality and both for quantum or classical statistical systems. Having at
disposal fast converging sequences, allows to draw conclusions on the basis of
shorter system sizes, and can be extremely important in particularly hard cases
like two-dimensional quantum systems with frustrations or when the sign problem
occurs. We test the effectiveness of our methods both analytically on the basis
of the one-dimensional XY model, and numerically at phase transitions occurring
in non integrable spin models. In particular, we show how a new Homogeneity
Condition Method is able to locate the onset of the
Berezinskii-Kosterlitz-Thouless transition making only use of ground-state
quantities on relatively small systems.Comment: 16 pages, 4 figures. New version including more general Ansaetze
basically applicable to all case
Monte Carlo investigations of phase transitions: status and perspectives
Using the concept of finite-size scaling, Monte Carlo calculations of various
models have become a very useful tool for the study of critical phenomena, with
the system linear dimension as a variable. As an example, several recent
studies of Ising models are discussed, as well as the extension to models of
polymer mixtures and solutions. It is shown that using appropriate cluster
algorithms, even the scaling functions describing the crossover from the Ising
universality class to the mean-field behavior with increasing interaction range
can be described. Additionally, the issue of finite-size scaling in Ising
models above the marginal dimension (d*=4) is discussed.Comment: 23 pages, including 14 PostScript figures. Presented at
StatPhys-Taiwan, August 9-16, 1999. Also available as PDF file at
http://www.cond-mat.physik.uni-mainz.de/~luijten/erikpubs.htm
A feasibility study of a rotary planar electrode array for electrical impedance mammography using a digital breast phantom
A feasibility study of an electrical impedance mammography (EIM) system
with a rotary planar electrode array, named RPEIM, is presented. The RPEIM
system is an evolution of the Sussex MK4 system, which is a prototype
instrument for breast cancer detection. Comparing it with the other planar
electrode EIM systems, the rotation feature enables a dramatic increase in
the number of independent measurements. To assist impedance evaluation
exploiting electrode array rotation, a synchronous mesh method is proposed.
Using the synchronous mesh method, the RPEIM system is shown to
have superior performance in image accuracy, spatial resolution and noise
tolerance over the MK4 system. To validate the study, we report simulations
based on a close-to-realistic 3D digital breast phantom, which comprises of:
skin, nipple, ducts, acinus, fat and tumor. A digital breast phantom of a real
patient is constructed, whose tumor was detected using the MK4 system. The
reconstructed conductivity image of the breast phantom indicates that the
breast phantom is a close replica of the patient’s real breast as assessed by the
MK4 system in a clinical trial. A comparison between the RPEIM system and
the MK4 system is made based on this phantom to assess the advantages of
the RPEIM system
Decadal changes of the Western Arabian sea ecosystem
Historical data from oceanographic expeditions and remotely sensed data on outgoing longwave radiation, temperature, wind speed and ocean color in the western Arabian Sea (1950–2010) were used to investigate decadal trends in the physical and biochemical properties of the upper 300 m. 72 % of the 29,043 vertical profiles retrieved originated from USA and UK expeditions. Increasing outgoing longwave radiation, surface air temperatures and sea surface temperature were identified on decadal timescales. These were well correlated with decreasing wind speeds associated with a reduced Siberian High atmospheric anomaly. Shoaling of the oxycline and nitracline was observed as well as acidification of the upper 300 m. These physical and chemical changes were accompanied by declining chlorophyll-a concentrations, vertical macrofaunal habitat compression, declining sardine landings and an increase of fish kill incidents along the Omani coast
On directed interacting animals and directed percolation
We study the phase diagram of fully directed lattice animals with
nearest-neighbour interactions on the square lattice. This model comprises
several interesting ensembles (directed site and bond trees, bond animals,
strongly embeddable animals) as special cases and its collapse transition is
equivalent to a directed bond percolation threshold. Precise estimates for the
animal size exponents in the different phases and for the critical fugacities
of these special ensembles are obtained from a phenomenological renormalization
group analysis of the correlation lengths for strips of width up to n=17. The
crossover region in the vicinity of the collapse transition is analyzed in
detail and the crossover exponent is determined directly from the
singular part of the free energy. We show using scaling arguments and an exact
relation due to Dhar that is equal to the Fisher exponent
governing the size distribution of large directed percolation clusters.Comment: 23 pages, 3 figures; J. Phys. A 35 (2002) 272
Knowledge of actions of inhaled corticosteroids in patients who did not persist drug treatment early
Objective To evaluate, among new users of inhaled corticosteroids that did not persist treatment, knowledge of inhaled corticosteroids' actions and whether they were instructed on the use of their inhaler. Setting Fifteen community pharmacies in The Netherlands. Methods Patients were interviewed by telephone. Their general practitioners provided diagnostic information and automated dispensing records were retrieved. Main outcome measures Knowledge of patients about the actions of inhaled corticosteroids. Results 230 (80.1%) of 287 patients were willing to participate. The majority (79.1%) of 230 patients was not aware of the anti-inflammatory actions of inhaled corticosteroids. Most patients were instructed on the use of their inhaler, predominantly by their physician (53%) or pharmacy (35.2%). Conclusions Although most patients reported inhaler instruction by at least one health care provider, the majority was unaware of inhaled corticosteroids' actions. Physicians and pharmacists should reconsider the instructions they provide especially to patients who should continuously use inhaled corticosteroids
Polycation-π Interactions Are a Driving Force for Molecular Recognition by an Intrinsically Disordered Oncoprotein Family
Molecular recognition by intrinsically disordered proteins (IDPs) commonly involves specific localized contacts and target-induced disorder to order transitions. However, some IDPs remain disordered in the bound state, a phenomenon coined "fuzziness", often characterized by IDP polyvalency, sequence-insensitivity and a dynamic ensemble of disordered bound-state conformations. Besides the above general features, specific biophysical models for fuzzy interactions are mostly lacking. The transcriptional activation domain of the Ewing's Sarcoma oncoprotein family (EAD) is an IDP that exhibits many features of fuzziness, with multiple EAD aromatic side chains driving molecular recognition. Considering the prevalent role of cation-π interactions at various protein-protein interfaces, we hypothesized that EAD-target binding involves polycation- π contacts between a disordered EAD and basic residues on the target. Herein we evaluated the polycation-π hypothesis via functional and theoretical interrogation of EAD variants. The experimental effects of a range of EAD sequence variations, including aromatic number, aromatic density and charge perturbations, all support the cation-π model. Moreover, the activity trends observed are well captured by a coarse-grained EAD chain model and a corresponding analytical model based on interaction between EAD aromatics and surface cations of a generic globular target. EAD-target binding, in the context of pathological Ewing's Sarcoma oncoproteins, is thus seen to be driven by a balance between EAD conformational entropy and favorable EAD-target cation-π contacts. Such a highly versatile mode of molecular recognition offers a general conceptual framework for promiscuous target recognition by polyvalent IDPs. © 2013 Song et al
The body unbound: ritual scarification and autobiographical forms in Wole Soyinka’s Aké: the years of childhood
The scarification in Aké is invested with major significance apropos Soyinka’s ideas on African
subjectivity. Scarification among the Yoruba is one of the rites of passage associated with personal
development. Scarification literally and metaphorically “opens” the person up socially and cosmically.
Personal formation and self-realization are enabled by the Yoruba social code brought into being
by its mythology. The meaning of the scarification incident in Aké is profoundly different. Determined
by the form of autobiography which creates a self-constituting subject, the enabling Yoruba sociocultural
context is elided. The story of Soyinka’s personal development is allegorical of the story
of the development of the modern African subject. For Soyinka, the African subject is a rational
subject whose constitution precludes the splitting of the scientific and spiritual which is a consequence
of the Cartesian rupture. The African subject should be open to other subjects and the object
world. Subjectivity constituted by the autobiographical mode closes off the opening up symbolically
signalled by scarification.Web of Scienc
CNS Expression of B7-H1 Regulates Pro-Inflammatory Cytokine Production and Alters Severity of Theiler's Virus-Induced Demyelinating Disease
The CNS is a unique organ due to its limited capacity for immune surveillance. As macrophages of the CNS, microglia represent a population originally known for the ability to assist neuronal stability, are now appreciated for their role in initiating and regulating immune responses in the brain. Theiler's murine encephalomyelitis virus (TMEV)-induced demyelinating disease is a mouse model of multiple sclerosis (MS). In response to TMEV infection in vitro, microglia produce high levels of inflammatory cytokines and chemokines, and are efficient antigen-presenting cells (APCs) for activating CD4+ T cells. However, the regulatory function of microglia and other CNS-infiltrating APCs in response to TMEV in vivo remains unclear. Here we demonstrate that microglia increase expression of proliferating cell nuclear antigen (PCNA), and phenotypically express high levels of major histocompatibility complex (MHC)-Class I and II in response to acute infection with TMEV in SJL/J mice. Microglia increase expression of the inhibitory co-stimulatory molecule, B7-H1 as early as day 5 post-infection, while CNS-infiltrating CD11b+CD11c−CD45HIGH monocytes/macrophages and CD11b+CD11c+CD45HIGH dendritic cells upregulate expression of B7-H1 by day 3 post-infection. Utilizing a neutralizing antibody, we demonstrate that B7-H1 negatively regulates TMEV-specific ex vivo production of interferon (IFN)-γ, interleukin (IL)-17, IL-10, and IL-2 from CD4+ and CD8+ T cells. In vivo blockade of B7-H1 in SJL/J mice significantly exacerbates clinical disease symptoms during the chronic autoimmune stage of TMEV-IDD, but only has minimal effects on viral clearance. Collectively, these results suggest that CNS expression of B7-H1 regulates activation of TMEV-specific T cells, which affects protection against TMEV-IDD
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