Acquisition Hardware for Imaging

In electron microscopy images can either be recorded in parallel (Transmission Electron Microscopy) or acquired as the variation in a signal as a probe is scanned over the specimen (Scanning Electron Microscopy). To extract the most information from an image requires that the best possible systems are used for acquiring image data. Ultimately, the limit to information capture is achieved when every electron from the scattering event of interest is recorded. The ideal system can be realised both for parallel recording with scientific grade CCD cameras, and for scanning microscopy with single electron counting electronics. The data rates from these different systems impose different constraints on the computer systems needed to acquire and display the incoming images

Mach's Principle and Model for a Broken Symmetric Theory of Gravity

We investigate spontaneous symmetry breaking in a conformally invariant gravitational model. In particular, we use a conformally invariant scalar tensor theory as the vacuum sector of a gravitational model to examine the idea that gravitational coupling may be the result of a spontaneous symmetry breaking. In this model matter is taken to be coupled with a metric which is different but conformally related to the metric appearing explicitly in the vacuum sector. We show that after the spontaneous symmetry breaking the resulting theory is consistent with Mach's principle in the sense that inertial masses of particles have variable configurations in a cosmological context. Moreover, our analysis allows to construct a mechanism in which the resulting large vacuum energy density relaxes during evolution of the universe.Comment: 9 pages, no figure

Homocysteine levels and treatment effect in the prospective study of pravastatin in the elderly at risk

Objectives: To assess the effect of preventive pravastatin treatment on coronary heart disease (CHD) morbidity and mortality in older persons at risk for cardiovascular disease (CVD), stratified according to plasma levels of homocysteine.<p></p> Design: A post hoc subanalysis in the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER), started in 1997, which is a double-blind, randomized, placebo-controlled trial with a mean follow-up of 3.2 years.<p></p> Setting: Primary care setting in two of the three PROSPER study sites (Netherlands and Scotland).<p></p> Participants: Individuals (n = 3,522, aged 70–82, 1,765 male) with a history of or risk factors for CVD were ranked in three groups depending on baseline homocysteine level, sex, and study site.<p></p> Intervention: Pravastatin (40 mg) versus placebo.<p></p> Measurements: Fatal and nonfatal CHD and mortality.<p></p> Results: In the placebo group, participants with a high homocysteine level (n = 588) had a 1.8 higher risk (95% confidence interval (CI) = 1.2–2.5, P = .001) of fatal and nonfatal CHD than those with a low homocysteine level (n = 597). The absolute risk reduction in fatal and nonfatal CHD with pravastatin treatment was 1.6% (95% CI = −1.6 to 4.7%) in the low homocysteine group and 6.7% (95% CI = 2.7–10.7%) in the high homocysteine group (difference 5.2%, 95% CI = 0.11–10.3, P = .046). Therefore, the number needed to treat (NNT) with pravastatin for 3.2 years for benefit related to fatal and nonfatal CHD events was 14.8 (95% CI = 9.3–36.6) for high homocysteine and 64.5 (95% CI = 21.4–∞) for low homocysteine.<p></p> Conclusion: In older persons at risk of CVD, those with high homocysteine are at highest risk for fatal and nonfatal CHD. With pravastatin treatment, this group has the highest absolute risk reduction and the lowest NNT to prevent fatal and nonfatal CHD.<p></p&gt

Quantification of High-Resolution Lattice Images and Electron Holograms

Progress towards the quantification of high-resolution electron microscopy and electron holograms has been achieved using digital acquisition with a slow-scan charge-coupled device (CCD) camera. Two applications are described: the precise measurement of lattice-fringe spacings and the determination of the mean inner potential. Lattice images can be characterized by a finite sum of two-dimensional sinusoids. A new method for measurement of the frequency, amplitude and phase of each sinusoid, based on an interpolation technique in reciprocal space, is presented. The method offers considerably higher precision for measurement of lattice fringes than the optical bench and is applicable to images recorded with an electron dose of less than 1 el / Å2 and specimen areas as small as 8 Å across. The attainable precision is dependent on specimen characteristics, electron dose and the size of the measured area, and ranges from 0.001 Å to 0.05 Å. An improved method has also been developed for measurement of mean inner potential using digital off-axis electron holograms from 90° crystal wedges. The value of (-14.21 ± 0.16) V obtained for GaAs represents the most accurate measurement yet reported for the mean inner potential

An observed 20-year time series of Agulhas leakage

We provide a time series of Agulhas leakage anomalies over the last 20-years from satellite altimetry. Until now, measuring the interannual variability of Indo-Atlantic exchange has been the major barrier in the investigation of the dynamics and large scale impact of Agulhas leakage. We compute the difference of transport between the Agulhas Current and Agulhas Return Current, which allows us to deduce Agulhas leakage. The main difficulty is to separate the Agulhas Return Current from the southern limb of the subtropical "supergyre" south of Africa. For this purpose, an algorithm that uses absolute dynamic topography data is developed. The algorithm is applied to a state-of-the-art ocean model. The comparison with a Lagrangian method to measure the leakage allows us to validate the new method. An important result is that it is possible to measure Agulhas leakage in this model using the velocity field along a section that crosses both the Agulhas Current and the Agulhas Return Current. In the model a good correlation is found between measuring leakage using the full depth velocities and using only the surface geostrophic velocities. This allows us to extend the method to along-track absolute dynamic topography from satellites. It is shown that the accuracy of the mean dynamic topography does not allow us to determine the mean leakage but that leakage anomalies can be accurately computed

Plasma NT-proBNP as predictor of change in functional status, cardiovascular morbidity and mortality in the oldest old: the Leiden 85-plus study

Pathophysiology, epidemiology and therapy of agein

Time trends in preventive drug treatment after myocardial infarction in older patients

Secondary preventive drug treatment in patients aged >= 60 years with a history of myocardial infarction was investigated for age-dependent differences in time trends. Sixteen general practices in the Netherlands participated. Preventive treatment with at least three of four drugs (antithrombotics, statins, beta-blockers, and/or angiotensin-converting enzyme inhibitors) increased significantly over time in all three age strata of older patients. Although the greatest relative increase (2.2 times greater) took place in patients aged >= 80 years, these patients consistently had most room for improvement.Public Health and primary careGeriatrics in primary car

One is not the other:Predicting offending after discharge from secure residential care of male adolescents with four risk profiles

Purpose: Adolescents who are admitted to secure residential care have a high risk of delinquency after discharge. However, this risk may differ between subgroups in this heterogeneous population of adolescents with severe psychiatric problems and disruptive problem behaviour. In this study, the predictive validity of four risk profiles was examined for the number of minor, moderate, and severe offences after discharge from secure residential care.Methods: The sample comprised 238 male former patients of a hospital for youth forensic psychiatry and orthopsychiatry in the Netherlands. In three Poisson regression analyses, the relationship between four previously identified risk profiles and the number of minor, moderate, and severe offences after discharge was examined.Results: The results showed that the four risk profiles differed significantly in the number of minor, moderate, and severe offences after discharge. Post hoc analysis revealed no mediating effect of termination of treatment on the relationship between the risk profiles and the number of minor, moderate, and severe offending after discharge.Conclusion: Adolescents with many risk factors in multiple domains and adolescents with mainly family risks have an increased risk of persistent delinquency after discharge. Treatment should be tailored more effectively to the specific risks and needs of these adolescents