Whole of degree curriculum design: Transitioning students in, through and out of higher education

Panel Discussio

Effects of total solar eclipse of 29 March 2006 on surface radiation

International audienceSolar irradiance spectral measurements were performed during a total solar eclipse. The spectral effect of the limb darkening to the global, direct irradiance and actinic flux measurements was investigated. This effect leads to wavelength dependent changes in the measured solar spectra showing a much more pronounced decrease in the radiation at the lower wavelengths. Radiative transfer model results were used for the computation of a correction for the total ozone measurements due to the limb darkening. This correction was found too small to explain the large decrease in total ozone column derived from the standard Brewer measurements, which is an artifact in the measured irradiance due to the increasing contribution of diffuse radiation against the decreasing direct irradiance caused by the eclipse. Calculations of the Extraterrestrial spectrum and the effective sun's temperatures, as measured from ground based direct irradiance measurements, showed an artificial change in the calculations of both quantities due to the fact that radiation coming from the visible part of the sun during the eclipse phases differs from the back body radiation described by the Planck's law

Spectral actinic flux in the lower troposphere: measurement and 1-D simulations for cloudless, broken cloud and overcast situations

In September 2002, the first INSPECTRO campaign to study the influence of clouds on the spectral actinic flux in the lower troposphere was carried out in East Anglia, England. Measurements of the actinic flux, the irradiance and aerosol and cloud properties were made from four ground stations and by aircraft. The radiation measurements were modelled using the uvspec model and ancillary data. For cloudless conditions, the measurements of the actinic flux were reproduced by 1-D radiative transfer modelling within the measurement and model uncertainties of about ±10%. For overcast days, the ground-based and aircraft radiation measurements and the cloud microphysical property measurements are consistent within the framework of 1-D radiative transfer and within experimental uncertainties. Furthermore, the actinic flux is increased by between 60-100% above the cloud when compared to a cloudless sky, with the largest increase for the optically thickest cloud. Correspondingly, the below cloud actinic flux is decreased by about 55-65%. Just below the cloud top, the downwelling actinic flux has a maximum that is seen in both the measurements and the model results. For broken clouds the traditional cloud fraction approximation is not able to simultaneously reproduce the measured above-cloud enhancement and below-cloud reduction in the actinic flux

Spectral actinic flux in the lower troposphere: measurement and 1-D simulations for cloudless, broken cloud and overcast situations

In September 2002, the first INSPECTRO campaign to study the influence of clouds on the spectral actinic flux in the lower troposphere was carried out in East Anglia, England. Measurements of the actinic flux, the irradiance and aerosol and cloud properties were made from four ground stations and by aircraft. The radiation measurements were modelled using the uvspec model and ancillary data. For cloudless conditions, the measurements of the actinic flux were reproduced by 1-D radiative transfer modelling within the measurement and model uncertainties of about ±10%. For overcast days, the ground-based and aircraft radiation measurements and the cloud microphysical property measurements are consistent within the framework of 1-D radiative transfer and within experimental uncertainties. Furthermore, the actinic flux is increased by between 60-100% above the cloud when compared to a cloudless sky, with the largest increase for the optically thickest cloud. Correspondingly, the below cloud actinic flux is decreased by about 55-65%. Just below the cloud top, the downwelling actinic flux has a maximum that is seen in both the measurements and the model results. For broken clouds the traditional cloud fraction approximation is not able to simultaneously reproduce the measured above-cloud enhancement and below-cloud reduction in the actinic flux

A two-parameter wind speed algorithm for Ku-band altimeters

Globally distributed crossovers of altimeter and scatterometer observations clearly demonstrate that ocean altimeter backscatter correlates with both the near-surface wind speed and the sea state. Satellite data from TOPEX/Poseidon and NSCAT are used to develop an empirical altimeter wind speed model that attenuates the sea-state signature and improves upon the present operational altimeter wind model. The inversion is defined using a multilayer perceptron neural network with altimeter-derived backscatter and significant wave height as inputs. Comparisons between this new model and past single input routines indicates that the rms wind error is reduced by 10%–15% in tandem with the lowering of wind error residuals dependent on the sea state. Both model intercomparison and validation of the new routine are detailed, including the use of large independent data compilations that include the SeaWinds and ERS scatterometers, ECMWF wind fields, and buoy measurements. The model provides consistent improvement against these varied sources with a wind-independent bias below 0.3 m s?1. The continuous form of the defined function, along with the global data used in its derivation, suggest an algorithm suitable for operational application to Ku-band altimeters. Further model improvement through wave height inclusion is limited due to an inherent multivaluedness between any single realization of the altimeter measurement pair [?o, HS] and observed near-surface winds. This ambiguity indicates that HS is a limited proxy for variable gravity wave properties that impact upon altimeter backscatter

Toll-like receptors 2 and 4 are potential therapeutic targets in peritoneal dialysis-associated fibrosis

Peritoneal dialysis (PD) remains limited by dialysis failure due to peritoneal membrane fibrosis driven by inflammation caused by infections or sterile cellular stress. Given the fundamental role of Toll-like receptors (TLRs) and complement in inflammation, we assessed the potential of peritoneal TLR2, TLR4 and C5a receptors, C5aR and C5L2, as therapeutic targets in PD-associated fibrosis. We detected TLR2–, TLR4–, and C5aR–mediated proinflammatory and fibrotic responses to bacteria that were consistent with the expression of these receptors in peritoneal macrophages (TLR2/4, C5aR) and mesothelial cells (TLR2, C5aR). Experiments in knockout mice revealed a major role for TLR2, a lesser role for TLR4, a supplementary role for C5aR, and no apparent activity of C5L2 in infection–induced peritoneal fibrosis. Similarly, antibody blockade of TLR2, TLR4, or C5aR differentially inhibited bacteria–induced profibrotic and inflammatory mediator production by peritoneal leukocytes isolated from the peritoneal dialysis effluent (PDE) of noninfected uremic patients. Additionally, antibodies against TLR2, TLR4, or the coreceptor CD14 reduced the profibrotic responses of uremic leukocytes to endogenous components present in the PDE of noninfected patients. Enhancing TLR2-mediated inflammation increased fibrosis in vivo. Furthermore, soluble TLR2 (sTLR2), a negative modulator of TLRs that we detected in PDE, inhibited PDE–induced, TLR2– or TLR4–mediated profibrotic responses. Notably, sTLR2 treatment markedly reduced Gram–positive and –negative bacteria–induced fibrosis in vivo, inhibiting proinflammatory and fibrotic genes without affecting infection clearance. These findings reveal the influence of peritoneal TLR2 and TLR4 on PD-associated fibrosis and describe a therapeutic strategy against fibrosi

Unconventional human T cells accumulate at the site of infection in response to microbial ligands and induce local tissue remodeling

The antimicrobial responsiveness and function of unconventional human T cells are poorly understood, with only limited access to relevant specimens from sites of infection. Peritonitis is a common and serious complication in individuals with end-stage kidney disease receiving peritoneal dialysis. By analyzing local and systemic immune responses in peritoneal dialysis patients presenting with acute bacterial peritonitis and monitoring individuals before and during defined infectious episodes, our data show that Vg9/ Vd2+ gd T cells and mucosal-associated invariant T cells accumulate at the site of infection with organisms producing (E)-4- hydroxy-3-methyl-but-2-enyl pyrophosphate and vitamin B2, respectively. Such unconventional human T cells are major producers of IFN-g and TNF-a in response to these ligands that are shared by many microbial pathogens and affect the cells lining the peritoneal cavity by triggering local inflammation and inducing tissue remodeling with consequences for peritoneal membrane integrity. Our data uncover a crucial role for Vg9/Vd2 T cells and mucosal-associated invariant T cells in bacterial infection and suggest that they represent a useful predictive marker for important clinical outcomes, which may inform future stratification and patient management. These findings are likely to be applicable to other acute infections where local activation of unconventional T cells contributes to the antimicrobial inflammatory response

Intercomparison of solar UV direct irradiance spectral measurements at Izana in June 2005

Spectral measurements of direct solar ultraviolet irradiance are very important for many applications in the field of atmospheric sciences. Despite its usefulness, few UV monitoring sites include such measurements in their regular observational programs. Standardization of measurement methodologies and calibration techniques is required in order to reach the quality standard of global irradiance measurements. This study presents preliminary results from an intercomparison campaign of seven UV spectroradiometers of different types that took place at the high altitude site of Izana (28.3°N, 16.5°W, 2367 m above sea level), in Tenerife, Canary Islands in June 2005

Commemorating the First World War in Britain: A Cultural Legacy of Media Remembrance

One of the often-overlooked legacies of the First World War is how the conflict established the media’s role in remembrance. In the years that have followed, media’s circulation of iconic images of national and local commemoration have enabled individuals to engage with public remembrance. This article takes a historical approach to First World War remembrance in Britain, looking at how the practices and meaning of remembrance became established, although they were never fixed but instead constantly shifting, reinvented and contested. They are also gendered, in remembrance, as in war, women, are often seen as to be playing supportive roles; yet within media texts, women have always found spaces to exert influence over who is remembered and how, as memories jostle for prominence