Fresh concrete pumping arrest investigation for thixotropy by a CFD modelling apporach

Concrete pumping operations determine construction speed, finishing quality, durability and even structural integrity. When pumping operations cannot be continued, most problems occur due to complex time-dependent transformations. This causes significant industrial costs (e.g. material and delay). Since time-dependent aspects are currently not fully understood and cannot be predicted, a way to quantify time-dependent aspects is needed. Therefore, we make an attempt by numerical simulation by comparing thixotropic cases with different pumping arresting times. After an introduction to fresh concrete rheology and numerical modelling, ten representative thixotropy cases are analysed. Despite some unresolved numerical instabilities, the numerical framework allows to estimate pumping pressure peaks after resting time. The results evaluate a thixotropy model, which is generally applicable for less thixotropic SCC’s. It is clear that flow re-initiation after rest in concrete pumping is poorly understood. Numerical simulation could be one approach for further analysis and is potentially important for practice. Future work such as simulation of concrete mixers, pressure increase after pumping arrest, formwork pressure decay and leakage are therefore recommended

Evolutionary relationships between Rhynchosporium lolii sp. nov. and other Rhynchosporium species on grass.

Copyright: 2013 King et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are creditedThe fungal genus Rhynchosporium (causative agent of leaf blotch) contains several host-specialised species, including R. commune (colonising barley and brome-grass), R. agropyri (couch-grass), R. secalis (rye and triticale) and the more distantly related R. orthosporum (cocksfoot). This study used molecular fingerprinting, multilocus DNA sequence data, conidial morphology, host range tests and scanning electron microscopy to investigate the relationship between Rhynchosporium species on ryegrasses, both economically important forage grasses and common wild grasses in many cereal growing areas, and other plant species. Two different types of Rhynchosporium were found on ryegrasses in the UK. Firstly, there were isolates of R. commune that were pathogenic to both barley and Italian ryegrass. Secondly, there were isolates of a new species, here named R. lolii, that were pathogenic only to ryegrass species. R. lolii was most closely related to R. orthosporum, but exhibited clear molecular, morphological and host range differences. The species was estimated to have diverged from R. orthosporum ca. 5735 years before the present. The colonisation strategy of all of the different Rhynchosporium species involved extensive hyphal growth in the sub-cuticular regions of the leaves. Finally, new species-specific PCR diagnostic tests were developed that could distinguish between these five closely related Rhynchosporium species.Peer reviewedFinal Published versio

Is the Sun Embedded in a Typical Interstellar Cloud?

The physical properties and kinematics of the partially ionized interstellar material near the Sun are typical of warm diffuse clouds in the solar vicinity. The interstellar magnetic field at the heliosphere and the kinematics of nearby clouds are naturally explained in terms of the S1 superbubble shell. The interstellar radiation field at the Sun appears to be harder than the field ionizing ambient diffuse gas, which may be a consequence of the low opacity of the tiny cloud surrounding the heliosphere. The spatial context of the Local Bubble is consistent with our location in the Orion spur.Comment: "From the Outer Heliosphere to the Local Bubble", held at International Space Sciences Institute, October 200

Safety and feasibility of switching from phenytoin to levetiracetam monotherapy for glioma-related seizure control following craniotomy: a randomized phase II pilot study

Seizures are common in patients with gliomas, and phenytoin (PHT) is frequently used to control tumor-related seizures. PHT, however, has many undesirable side effects (SEs) and drug interactions with glioma chemotherapy. Levetiracetam (LEV) is a newer antiepileptic drug (AED) with fewer SEs and essentially no drug interactions. We performed a pilot study testing the safety and feasibility of switching patients from PHT to LEV monotherapy for postoperative control of glioma-related seizures. Over a 13-month period, 29 patients were randomized in a 2:1 ratio to initiate LEV therapy within 24 h of surgery or to continue PHT therapy. 6 month follow-up data were available for 15 patients taking LEV and for 8 patients taking PHT. In the LEV group, 13 patients (87%) were seizure-free. In the PHT group, 6 patients (75%) were seizure-free. Reported SEs at 6 months was as follows (%LEV/%PHT group): dizziness (0/14), difficulty with coordination (0/29), depression (7/14) lack of energy or strength (20/43), insomnia (40/43), mood instability (7/0). The pilot data presented here suggest that it is safe to switch patients from PHT to LEV monotherapy following craniotomy for supratentorial glioma. A large-scale, double-blinded, randomized control trial of LEV versus PHT is required to determine seizure control equivalence and better assess differences in SEs

Surveillance of the short-term impact of fine particle air pollution on cardiovascular disease hospitalizations in New York State

<p>Abstract</p> <p>Background</p> <p>Studies have shown that the effects of particulate matter on health vary based on factors including the vulnerability of the population, health care practices, exposure factors, and the pollutant mix.</p> <p>Methods</p> <p>We used time-stratified case-crossover to estimate differences in the short-term impacts of PM_2.5on cardiovascular disease hospital admissions in New York State by geographic area, year, age, gender, co-morbid conditions, and area poverty rates.</p> <p>Results</p> <p>PM_2.5had a stronger impact on heart failure than other cardiovascular diagnoses, with 3.1% of heart failure admissions attributable to short-term PM_2.5exposure over background levels of 5 ug/m³. Older adults were significantly more susceptible to heart failure after short-term ambient PM_2.5exposure than younger adults.</p> <p>Conclusion</p> <p>The short-term impact of PM_2.5on cardiovascular disease admissions, and modifications of that impact, are small and difficult to measure with precision. Multi-state collaborations will be necessary to attain more precision to describe spatiotemporal differences in health impacts.</p

Assessing the efficiency of mother-to-child HIV prevention in low- and middle-income countries using data envelopment analysis

AIDS is one of the most significant health care problems worldwide. Due to the difficulty and costs involved in treating HIV, preventing infection is of paramount importance in controlling the AIDS epidemic. The main purpose of this paper is to explore the potential of using Data Envelopment Analysis (DEA) to establish international comparisons on the efficiency of implementation of HIV prevention programmes. To do this we use data from 52 low- and middle-income countries regarding the prevention of mother-to-child transmission of HIV. Our results indicate that there is a remarkable variation in the efficiency of prevention services across nations, suggesting that a better use of resources could lead to more and improved services, and ultimately, prevent the infection of thousands of children. These results also demonstrate the potential strategic role of DEA for the efficient and effective planning of scarce resources to fight the epidemic