Effect of dialysis membrane and patient's age on signs of dialysis-related amyloidosis

Effect of dialysis membrane and patient's age on signs of dialysis-related amyloidosis. This 12 center study was designed to assess factors affecting the development and progression of β2-microglobulin amyloidosis in long-term dialysis. A total of 221 patients who were on hemodialysis for more than five years, and who were treated the entire time only with AN69, a biocompatible, highly permeable membrane, or cuprophane, a less permeable, poorly biocompatible membrane (Cell) were evaluated for time on dialysis, development of carpal tunnel syndrome, and cystic bone lesions X-ray documentation was taken in a minimum of four of the six following joints: both hips, wrists and shoulders. The data demonstrate that patients treated solely by AN69 membranes display signs of bone amyloidosis less frequently than do those treated by Cell membranes. Age at onset of dialysis was found to have a striking correlation with the development of carpal tunnel syndrome and bone amyloidosis, while no significant influence was found for hyperparathyroidism, sex or year of first dialysis

Sea-ice simulations in the Weddell Sea

A model of sea-ice formation and movement has been developed and applied to a sector of the Southern Ocean including the Weddell Sea and the Drake Passage. This sea-ice model with leads is described in two parts : - the thermodynamical component, which represents the freezing and melting processes due to energy fluxes , between the atmosphere, ice, and ocean; - the dynamical component, presently limited to the computation of ice movement due to wind. Results from this model, including ice thickness, temperature. and spatial extent, will be presented and discussed for a particular point and for the whole area

Simulations of the annual sea-ice cover in the Weddell Sea

A modelof sea-ice formation has been developed and applied to a sector of the Southern Ocean, including the Weddell Sea and the Drake Passage; it describes the annual cycle of sea-ice thickness and its spatial extent. This sea-ice model with leads consists of two parts: - the thermodynamical component which manages the freezing and melting processes due to energy fluxes between the atmosphere, ice and ocean. This component computes also the heat and salt transfers between mixed layer and deep ocean; - the dynamical component limited in the present version of the model to the computation of ice movement due to wind and surface current. The surface energy budget, heat and salt exchanges and momentum transfers are modelled and/or parameterised frorn monthly-averaged climatological data (wind, air temperature, dew point, cloudiness and snowfall) and annually- averaged values of temperature and salinity in the ocean. These data and the results of the sea-ice model, including ice thickness, temperature, mixed-layer depth and ice extent, are presented and discussed at specific points (offshore and coastal) and for the whole area. The sea-ice model has been applied to the Weddell Sea according to two methods: the "layer method" where the ocean depth is limited to a chosen value and the "robust-diagnostic method" where the obervations constrain the model with a short damping time. The results of both methods show good agreement with the observed amplitude for ice extent and the mean oceanic heat fluxes exchanged between ice and ocean. The sea-ice model using the robust-diagnostic method gives a smaller ice thickness than the layer method and better conserves salt and energy

Effects of relative humidity and temperature on sulphate aerosol optical properties

During their interaction with water vapor, hygroscopic aerosols modify their size, shape and refractive index, which alters their radiative properties. Furthermore, when the temperature changes, the equilibrium between the water vapor pressure above the surface of the liquid aerosols and the ambient water vapor pressure is affected, leading to a modification on the aerosol size and refractive index. This paper presents a study of the influence of temperature on sulphate aerosol optical properties. Our results indicate that both sulphate specific extinction and asymmetry factor are affected by temperature changes via the temperature dependence of the growth factor and of the refractive index of the humidified particles. However these changes appears to be of minor importance compared to the modifications introduced in response to relative humidity changes. This finding seems to give credence to the often adopted assumption of using optical constants and thermodynamic properties of the aerosol chemical species at fixed temperature of 25°C at which the major measurement have been made

Transient climate simulation forced by natural and anthropogenic climate forcings

Numerical experiments have been carried Out with a two-dimensional sector-averaged global climate model coupled to a diffusive ocean in order to assess the potential impact of four hypothesized mechanisms of decadal to century-scale climate variability, both natural and anthropogenically induced: (1) solar variability: (2) variability in volcanic aerosol loading of the atmosphere (3) anthropogenic increase Of sulphate aerosols' concentration: (4) anthropogenic increase of greenhouse gas concentrations. Our results suggest that neither the individual responses nor the combined natural or anthropogenic forcings allow one to reproduce all of the recorded major temperature fluctuations since the latter half of the 19th century. They show that these temperature variations are the result of both naturally driven climate fluctuations and the effects of industrialization. By contrast, the dominant cause of decade-to-century-scale variability of the 21st Century is likely to be changes in atmospheric trace-as concentrations. Indeed, when the solar, volcanic, and tropospheric aerosols forcings used in our experiments are extended into the future, they are unable to counter the expected greenhouse warming. Copyright (C) 2002 Royal Meteorological Society

Potential role of solar variability as an agent for climate change

Numerical experiments have been carried out with a two-dimensional sector averaged global climate model in order to assess the potential impact of solar variability on the Earth's surface temperature from 1700 to 1992. This was done by investigating the model response to the variations in solar radiation caused by the changes in the Earth's orbital elements, as well as by the changes intrinsic to the Sun. In the absence of a full physical theory able to explain the origin of the observed total solar irradiance variations, three different total solar irradiance reconstructions have been used. A total solar irradiance change due to the photospheric effects incorporated in the Willson and Hudson (1988) parameterization, and the newly reconstructed solar total irradiance variations from the solar models of Hoyt and Schatten (1993) and Lean et al. (1995). Our results indicate that while the influence of the orbital forcing on the annual and global mean surface temperature is negligible at the century time scale, the monthly mean response to this forcing can be quite different from one month to another. The modelled global warming due to the three investigated total solar irradiance reconstructions is insufficient to reproduce the observed 20th century warming. Nevertheless, our simulated surface temperature response to the changes in the Sun's radiant energy output suggests that the Gleissberg cycle (approximate to 88 years) solar forcing should not be neglected in explaining the century-scale climate variations. Finally, spectral analysis seems to point out that the 10- to 12-year oscillations found in the recorded Northern Hemisphere temperature variations from 1700 to 1992 could be unrelated to the solar forcing. Such a result could indicate that the eleven-year period which is frequently found in climate data might be related to oscillations in the atmosphere or oceans, internal to the climate system

A European exchange scheme for junior doctors in internal medicine 1977-91: experiences of participants and organisers.

A retrospective survey was undertaken of the participants in and the organisers of an exchange scheme for junior physicians which has operated since 1977 between leading hospitals in countries of the European Community and Switzerland. The exchange has clinical, research, educational and cultural objectives and the survey sought to record the experiences of participants and their chiefs of service and note the strengths and weaknesses of the scheme as well as problems encountered with it. Overall, the participants' reports of their experiences of the scheme were favourable. Chiefs of host departments were enthusiastic about the interaction between participants and the host institutions. The impact of the programme on the junior doctors' educational and career development was variable though generally positive; major career changes were rare, the common pattern being one of helpful focusing of career intentions. Problems were relatively infrequent, mostly related to poor briefing, finances and bureaucracy. Few general international differences of experience of the scheme emerged