Improved formulation for compressive fatigue strength of concrete

This is the author accepted manuscript. The final version is available from CRC Press via https://doi.org/10.1201/b18972-139Cracks are inherent in reinforced concrete structures. The origin of cracks can be manifold. At early stages they can be caused by plastic settlement, shrinkage, drying shrinkage, etc. Typically, the most severe forms of cracking in reinforced concrete structures are those caused by the corrosion of the reinforcing bars. Corrosion products are expansive in nature and tend to generate tensile stresses in the concrete surrounding the corroding bars. As soon as these stresses exceed the tensile capacity of the concrete, cracks around and along the reinforcing bars are formed. In assessing existing structures engineers often notice severe cracking due to corrosion or longitudinal cracks due to plastic shrinkage e.g. in the anchorage zones. The section loss of these bars can easily be taken into consideration when performing load bearing capacity checks, but questions arise with respect to the remaining bond capacity of the rebars in the cracked concrete. This study aims to quantify the influence of different parameters on the bond strength of reinforcing bars in cracked concrete. Rather than performing accelerated corrosion tests, it focuses on the effect of cracking itself (in absence of corrosion products) so the results can be used for non-corrosion related cases as well. Parameters under investigation include the confinement, concrete cover, crack direction and crack extension. Results show that single cracks as narrow as 0.03 mm can have a significant influence on the obtained bond strengths.The authors would like to gratefully acknowledge the financial support of the UK Engineering and Physical Sciences Research Council (EPSRC) through the EPSRC Project ‘Reinforced concrete half-joint structures: Structural integrity implications of reinforcement detailing and deterioration’ [Grant no. EP/K016148/1]

第912回千葉医学会整形外科例会

<p>(A) Emission spectrum of CaAl₂O₄:Eu²⁺, Nd³⁺ crystals curves depending on H₃BO₃ concentration. (B) Decay curves depending on H₃BO₃ concentration. (C) Magnified views of the graph in (B). (D) Decay curves in log scale depending on H₃BO₃ concentration. (E) Relative initial intensity measured at 5s (relative values where the value of control sample #1 is 1.0) depending on H₃BO₃ concentration.</p

Limaprost and the Risk of Bleeding: A Self-Controlled Case Series Study

Objective To investigate the association between the use of limaprost and the risk of bleeding. Methods A self-controlled case series analysis was conducted using the National Health Insurance Service-National Sample Cohort database in South Korea. We identified patients aged 18 years or older who had at least one prescription of limaprost and were diagnosed with at least one case of bleeding between 2003 and 2019. The incidence rate ratio (IRR) of bleeding was calculated by dividing the incidence rate in the exposed period to limaprost by that in the unexposed period and adjusted for age using conditional Poisson regression model. Results Among 72,860 patients with limaprost prescriptions and bleeding diagnoses, there were 184,732 events of bleeding. After adjusting for age, the IRR was 1.47 (95% confidence interval [CI], 1.43–1.50), wherein the IRR was the highest during the 0–7 days after limaprost initiation (IRR, 2.11; 95% CI, 2.03–2.18). Risk of bleeding was higher when limaprost was concomitantly used with antithrombotics or other drugs for spinal stenosis treatment, and when higher daily doses of limaprost were administered. Conclusion Our findings suggest that the risk of bleeding increased by 1.5-fold in periods of limaprost exposure compared to unexposed periods, with particularly higher risks observed during the first week after limaprost initiation, with concomitant drugs related to bleeding, and with a higher daily dose. A careful risk-benefit assessment is warranted when initiating limaprost, especially when administered with other medications or in higher daily doses

Influence of life-history traits on the occurrence of carnivores within exotic Eucalyptus plantations

Aim The world's forested area has been declining, especially in developing countries. In contrast, forest plantations are increasing, particularly exotic Eucalyptus plantations, which cover nowadays over 20 million ha worldwide. This global landscape change affects native communities, especially those at higher trophic levels that are affected by bottom–up cascading effects, such as carnivores. We seek to identify the general life‐history traits of mammalian carnivore species that use exotic Eucalyptus plantations. Location We reviewed 55 studies reporting carnivore presence in Eucalyptus plantations worldwide. Methods We consider seven species life‐history traits (generation length, social behaviour, body mass, energetic trophic level, diet diversity, habitat generalist/specialist and locomotion mode) as candidate drivers. We used generalized linear mixed models, with life‐history traits as fixed factors, and study as well as carnivore species as random factors. We obtained the carnivore occurrence data from the literature (detection of 42 different species, from seven families). We considered non‐detected species those with an IUCN Red List of Threatened Species estimated distribution range overlapping with the study areas, but not recorded by the studies. Results While we found no evidence of an effect of any of the other life‐history traits tested, our modelling procedure indicated that habitat generalist species are more likely to use Eucalyptus forests than specialist species. Main conclusions Our results, therefore, confirm an impoverishment of predator communities in disturbed environments, with the exclusion of the most specialist predators, leading to fragmentation of their populations and, ultimately contributing to their local extinction. The local extinction of specialist carnivores may lead to “functional homogenization” of communities within plantations, modifying ecosystem functioning with a negative impact on plantations’ productivity, profitability and services.info:eu-repo/semantics/publishedVersio

Machine learning prediction of incidence of Alzheimer’s disease using large-scale administrative health data

Nationwide population-based cohort provides a new opportunity to build an automated risk prediction model based on individuals’ history of health and healthcare beyond existing risk prediction models. We tested the possibility of machine learning models to predict future incidence of Alzheimer’s disease (AD) using large-scale administrative health data. From the Korean National Health Insurance Service database between 2002 and 2010, we obtained de-identified health data in elders above 65 years (N = 40,736) containing 4,894 unique clinical features including ICD-10 codes, medication codes, laboratory values, history of personal and family illness and socio-demographics. To define incident AD we considered two operational definitions: “definite AD” with diagnostic codes and dementia medication (n = 614) and “probable AD” with only diagnosis (n = 2026). We trained and validated random forest, support vector machine and logistic regression to predict incident AD in 1, 2, 3, and 4 subsequent years. For predicting future incidence of AD in balanced samples (bootstrapping), the machine learning models showed reasonable performance in 1-year prediction with AUC of 0.775 and 0.759, based on “definite AD” and “probable AD” outcomes, respectively; in 2-year, 0.730 and 0.693; in 3-year, 0.677 and 0.644; in 4-year, 0.725 and 0.683. The results were similar when the entire (unbalanced) samples were used. Important clinical features selected in logistic regression included hemoglobin level, age and urine protein level. This study may shed a light on the utility of the data-driven machine learning model based on large-scale administrative health data in AD risk prediction, which may enable better selection of individuals at risk for AD in clinical trials or early detection in clinical settings

Forest Restoration in a Fog Oasis: Evidence Indicates Need for Cultural Awareness in Constructing the Reference

Background: In the Peruvian Coastal Desert, an archipelago of fog oases, locally called lomas, are centers of biodiversity and of past human activity. Fog interception by a tree canopy, dominated by the legume tree tara (Caesalpinia spinosa), enables the occurrence in the Atiquipa lomas (southern Peru) of an environmental island with a diverse flora and high productivity. Although this forest provides essential services to the local population, it has suffered 90% anthropogenic reduction in area. Restoration efforts are now getting under way, including discussion as to the most appropriate reference ecosystem to use. Methodology/Principal Findings: Genetic diversity of tara was studied in the Atiquipa population and over a wide geographical and ecological range. Neither exclusive plastid haplotypes to loma formations nor clear geographical structuring of the genetic diversity was found. Photosynthetic performance and growth of seedlings naturally recruited in remnant patches of loma forest were compared with those of seedlings recruited or planted in the adjacent deforested area. Despite the greater water and nitrogen availability under tree canopy, growth of forest seedlings did not differ from that of those recruited into the deforested area, and was lower than that of planted seedlings. Tara seedlings exhibited tight stomatal control of photosynthesis, and a structural photoprotection by leaflet closure. These drought-avoiding mechanisms did not optimize seedling performance under the conditions produced by forest interception of fog moisture. Conclusions/Significance: Both weak geographic partitioning of genetic variation and lack of physiological specialization of seedlings to the forest water regime strongly suggest that tara was introduced to lomas by humans. Therefore, the most diverse fragment of lomas is the result of landscape management and resource use by pre-Columbian cultures. We argue that an appropriate reference ecosystem for ecological restoration of lomas should include sustainable agroforestry practices that emulate the outcomes of ancient uses