Chloride Ingress of Carbonated Blast Furnace Slag Cement Mortars

In the Netherlands civil engineering structures, such as overpasses, bridges and tunnels are generally built using blast furnace slag cement (BFSC, CEM III/B) concrete, because of its high resistance against chloride penetration. Although the Dutch experience regarding durability performance of BFSC concrete has been remarkably good, its resistance to carbonation is known to be sensitive, especially when the used slag percentage is high. In a field investigation on a highway overpass damage was found in sheltered elements such as abutments and intermediate supports, which was attributed to chloride induced corrosion enhanced by carbonation that occurred prior to the chloride exposure. Many structures built using BFSC could be prone to this mechanism, i.e. carbonation enhanced chloride induced corrosion, negatively affecting their durability. Focus of the research was given on the influence of carbonation on the chloride penetration resistance of BFSC mortars with varying slag content. In light of the characteristics from the overpass case, it was assumed that first there is a period of carbonation during sheltered exposure, and subsequently joint leakage causes exposure to chlorides. In order to identify the influence of slag content on carbonation, chloride penetration resistance and their coupled effect, mortars with twelve cement blends in a range of 0-70% slag were evaluated based on chloride migration coefficient, accelerated carbonation and electrical resistivity. This study shows that carbonation of BFSC mortars increases the porosity, consequently decreasing the chloride penetration resistance. Binders with 50% or more slag were found to have a significantly lower resistance after carbonation. Consequently, the chloride penetration resistance of a given concrete cover strongly depends on the duration of carbonation and the resulting carbonation depth, hence influencing its lifespan. The service life was estimated using a simplified model for the chloride penetration time of a combined carbonated and uncarbonated layer. It was found that mortar with a slag content between 35 and 50% that was carbonated before chloride exposure show the lowest influence of carbonation on the chloride penetration resistance. © Springer International Publishing AG 2018. Bam; Cement and Beton Centrum; et al.; Rijkswaterstaat - Ministry of Infrastructure and the Environment; Van Hattum en Blankevoort; VolkerInfr

Outcome measures in post-stroke arm rehabilitation trials: do existing measures capture outcomes that are important to stroke survivors, carers, and clinicians?

Objective: We sought to (1) identify the outcome measures currently used across stroke arm rehabilitation randomized trials, (2) identify and compare outcomes important to stroke survivors, carers and clinicians and (3) describe where existing research outcome measures capture outcomes that matter the most to stroke survivors, carers and clinicians and where there may be discrepancies. Methods: First, we systematically identified and extracted data on outcome measures used in trials within a Cochrane overview of arm rehabilitation interventions. Second, we conducted 16 focus groups with stroke survivors, carers and clinicians using nominal group technique, supplemented with eight semi-structured interviews, to identify these stakeholders’ most important outcomes following post-stroke arm impairment. Finally, we described the constructs of each outcome measure and indicated where stakeholders’ important outcomes were captured by each measure. Results: We extracted 144 outcome measures from 243 post-stroke arm rehabilitation trials. The Fugl-Meyer Assessment Upper Extremity section (used in 79/243 trials; 33%), Action Research Arm Test (56/243; 23%), and modified Ashworth Scale (53/243; 22%) were most frequently used. Stroke survivors (n = 43), carers (n = 10) and clinicians (n = 58) identified 66 unique, important outcomes related to arm impairment following stroke. Between one and three outcomes considered important by the stakeholders were captured by the three most commonly used assessments in research. Conclusion: Post-stroke arm rehabilitation research would benefit from a reduction in the number of outcome measures currently used, and better alignment between what is measured and what is important to stroke survivors, carers and clinicians

On the kinematics of the Local cosmic void

We collected the existing data on the distances and radial velocities of galaxies around the Local Void in the Aquila/Hercules to examine the peculiar velocity field induced by its underdensity. A sample of 1056 galaxies with distances measured from the Tip of the Red Giant Branch, the Cepheid luminosity, the SNIa luminosity, the surface brightness fluctuation method, and the Tully-Fisher relation has been used for this purpose. The amplitude of outflow is found to be ~300 km/s. The galaxies located within the void produce the mean intra-void number density about 1/5 of the mean external number density of galaxies. The void's population has a lower luminosity and a later morphological type with the medians: M_B = -15.7^m and T = 8 (Sdm), respectively.Comment: Version 1. 14 pages, 8 figures, 2 tables. Accepted to Astrophysics, Volume 54, Issue

Kanamycin resistance during in vitro development of pollen from transgenic tomato plants

Effects of kanamycin on pollen germination and tube growth of pollen from non-transformed plants and from transgenic tomato plants containing a chimaeric kanamycin resistance gene were determined. Germination of pollen was not affected by the addition of kanamycin to the medium in both genotypes. Kanamycin, however, severely affected tube growth of pollen from non-transformed plants, while pollen from plants containing the chimaeric gene were less sensitive and produced significantly longer tubes at kanamycin concentrations between 200-400 mg l-1. Apparently, this resistance for kanamycin correlates with the expression of the chimaeric gene during male gametophytic development.

Functional outcome 5 years after non-operative treatment of type A spinal fractures

This study was conducted to study the functional outcome after non-operative treatment of type A thoracolumbar spinal fractures without neurological deficit. Functional outcome was determined following the International Classification of Functioning, Disability and Health, measuring restrictions in body function and structure, restrictions in activities, and restrictions in participation/quality of life. All patients were treated non-operatively for a type A thoracolumbar (Th11-L4) spinal fracture at the University Hospital Groningen, The Netherlands. Thirty-three of the eighty-one selected patients agreed to participate in the study (response-rate 41%). Respondents were older than non-respondents (mean 50.5 years vs. 39.2 years), but did not differ from each other concerning injury-related variables. Patients with a neurological deficit were excluded. Treatment consisted either of mobilisation without brace, or of bedrest followed by wearing a brace. Restrictions in body function and structure were measured by physical tests (dynamic lifting test and bicycle ergometry test); restrictions in activities were measured by means of questionnaires, the Roland Morris Disability Questionnaire (RMDQ) and Visual Analogue Scale Spine Score (VAS). Restrictions in participation/quality of life were assessed with the Short Form 36 (SF-36) and by means of return to work status. Thirty-seven per cent of the patients were not able to perform the dynamic lifting test within normal range. In the ergometry test, 40.9% of the patients performed below the lowest normal value, 36.4% of the patients achieved a high VO2-max. Mean RMDQ-score was 5.2, the mean VAS-score was 79. No significant differences between patients and healthy subjects were found in SF-36 scores, neither were differences found between braced and unbraced patients in any of the outcome measures. Concerning the return to work status, 10% of the subjects had stopped working and received social security benefits, 24% had arranged changes in their work and 14% had changed their job. We conclude that patients do reasonably well 5 years after non-operative treatment of a thoracolumbar fracture, although outcome is diverse in the different categories and physical functioning seems restricted in a considerable number of patients.</p

Botshabelo: Reaksie van 'n tipiese slaapdorp op veranderende sosio-ekonomiese omstandighede in 'n "Nuwe Suid-Afrika“

Research has indicated that changing socio-economic conditions in a “New South Africa” have wide-reaching consequences in a “dormitory town ” such as Botshabelo. The purpose of this article is to determine which changes in respect of demographic and related aspects, as well as in the field of economics, have occurred in Bot­shabelo over a period of three years. A comparison of data obtained during surveys undertaken in 1988/89 and again in 1991 can throw light on changes which have occurred.&nbsp;As far as the demographic profile of the population is concerned, informa­tion was obtained during both the 1988/89 and 1991 surveys on a sample basis by means of personal interviews conducted within the community on the basis of interview schedules. During both surveys economic data was also obtained by means of interviews con­ducted with various enterprises on the basis of interview schedules. The tech­nique of input-output analysis was employed on both occasions to analyse the local economy.&nbsp;Aspects discussed in the article are estimated population size, factors influencing population growth, such as&nbsp;the composition and size of house­holds, age distribution o f the commu­nity, births and mortality, as well as expected future population growth. This is followed by a discussion of the performance of formal enterprises with regard to local sales, value added, import and exogenous demand, as well as of changes with regard to job op­portunities and work-place, distribu­tion of the labour force according to sector, the economically active popula­tion according to industry, sales and income of households.*This article is written in Afrikaans

Familial paragangliomas

Paragangliomas are rare tumours of the autonomic nervous system and occur in sporadic and hereditary forms. They are usually benign and have a low mortality. However, they cause significant morbidity related to their mass effect. Genetic predisposition can occur within the familial tumour syndromes multiple endocrine neoplasia type 2 (MEN 2), von Hippel-Lindau (VHL) and neurofibromatosis type 1 (NF-1), or be due to mutations in genes specific to the development of paraganglioma only. Compared to sporadic forms, familial paragangliomas tend to present at a younger age and at multiple sites. Tumours should be diagnosed and resected as early as possible, as it has been shown that morbidity is related to tumour size. This article gives an overview of the current literature on the origin of the different forms of paragangliomas, DNA diagnosis, as well as biochemical and radiological screening guidelines

ROSAT HRI Observations of the Crab Pulsar: An Improved Temperature upper limit for PSR 0531+21

ROSAT HRI observations have been used to determine an upper limit of the Crab pulsar surface temperature from the off-pulse count rate. For a neutron star mass of 1.4 \Mo and a radius of 10 km as well as the standard distance and interstellar column density, the redshifted temperature upper limit is\/ $T_s^\infty \le 1.55\times 10^6$ K $(3\sigma)$. This is the lowest temperature upper limit obtained for the Crab pulsar so far. Slightly different values for $T_s^\infty$ are computed for the various neutron star models available in the literature, reflecting the difference in the equation of state.Comment: 5 pages, uuencoded postscript, to be published in the Proceedings of the NATO Advanced Study Insitute on "Lives of the Neutron Stars", ed. A. Alpar, U. Kiziloglu and J. van Paradijs ( Kluwer, Dordrecht, 1995 )

Bottom-up effects of a no-take zone on endangered penguin demographics.

This is the author accepted manuscript. The final version is available from The Royal Society via the DOI in this record.Marine no-take zones can have positive impacts for target species and are increasingly important management tools. However, whether they indirectly benefit higher order predators remains unclear. The endangered African penguin (Spheniscus demersus) depends on commercially exploited forage fish. We examined how chick survival responded to an experimental 3-year fishery closure around Robben Island, South Africa, controlling for variation in prey biomass and fishery catches. Chick survival increased by 18% when the closure was initiated, which alone led to a predicted 27% higher population compared with continued fishing. However, the modelled population continued to decline, probably because of high adult mortality linked to poor prey availability over larger spatial scales. Our results illustrate that small no-take zones can have bottom-up benefits for highly mobile marine predators, but are only one component of holistic, ecosystem-based management regimes.We thank the Earthwatch Institute, Bristol Zoological Society, Leiden Conservation Foundation and National Research Foundation