Stability Analysis of Implicit-Explicit Class for Solving ODEs and DDEs

Implicit-Explicit schemes have been widely used, it reduces the computational work for solving differential equations which have both stiff and non-stiff parts . In this paper an implicit-explicit linear multistep method for solving ordinary and delay differential equations is introduced. In both cases we are going to study the stability of the method using two approaches and the stability regions will be ploted. Numerical tests are introduced

Effect of organic fertilizers combined with benzo (1,2,3) thiadiazole-7-carbothioic acid S-methyl ester (BTH) on the cucumber powdery mildew and the yield production

Organic fertilizers such as compost, compost tea and seaweed extracts (Algean) combined with benzo (1,2,3) thiadiazole-7-carbothioic acid S-methyl ester (BTH)) showed significant effect on the powdery mildew-infected cucumber leaves with Sphaerotheca fuliginea. We have shown that spraying the infected cucumber leaves with the BTH (0.05 mM) combined with the organic fertilizers strongly decreased the disease severity of the cucumber powdery mildew fungus from 85.1% to 3.4% as compared to the control leaves which infected only with the pathogen. Furthermore, organic fertilizers combined with BTH increased significantly vegetative growth characters of cucumber (stem length, number of leaves /plant, leaf area /plant and chlorophyll content) especially at the earlier stage of growth as compared to the control plants (chemical fertilizer only). Also, most of the organic materials produced the highest cucumber early yield and fruit quality, but total yield was equal or less than the chemical fertilizers. Interestingly enough, that organic fertilizers combined with BTH elevated the ascorbic acid content (chemical quality of cucumber fruits) and decreased the nitrate content which very harmful as well as increased the fruit yields as compared to the control plants

A Multi-Path Approach to Histology Volume Reconstruction

This paper presents a method for correcting erratic pairwise registrations when reconstructing a volume from 2D histology slices. Due to complex and unpredictable alterations of the content of histology images, a pairwise rigid registration between two adjacent slices may fail systematically. Conversely, a neighbouring registration, which potentially involves one of these two slices, will work. This grounds our approach: using correct spatial correspondences established through neighbouring registrations to account for direct failures. We propose to search the best alignment of every couple of adjacent slices from a finite set of transformations that involve neighbouring slices in a transitive fashion. Using the proposed method, we obtained reconstructed volumes with increased coherence compared to the classical pairwise approach, both in synthetic and real data

Improvement of hydration products for self-compacting concrete by using magnetized water

Magnetized water (MW) is one of the most effective and economical ways to improve the properties of self-compacting concrete (SCC). Therefore, the aim of this study is to improve the fresh, mechanical, and microstructural properties of SCC using MW. For this purpose, a total of 12 mixes were produced with silica fume (SF) content (5% and 10% by weight of cement), and the mixing water passed through a permanent magnetic field (with a strength of 1.4 T) for 50, 100, and 150 cycles. Tests were performed for fresh properties (Slump flow, T50cm, V-funnel, and L-box), for mechanical properties (compressive, flexural, and tensile strength), and for microstructure properties (SEM, EDX, and TGA/DTG). The optimum result in compressive strength was achieved in the mix M8 using 5% silica fume and 150 cycles of MW. For fresh properties, the mix M4 using 150 cycles without SF had the workability enhanced by 11% compared to the control mix, and SEM and EDX tests indicated that SCC mixes prepared with MW had more C-S-H, less CH, and were denser. In addition, TGA/DTG analysis showed that the rate of hydration of mix M8 was reached by 61% at 28 days.

Effect of aggregates with high gypsum content on the performance of concrete

Sulfates in fine aggregate are a major problem when it exists in excessive amount especially in the Middle East and Iraq. Most of sulfate salts in fine aggregate are composed of calcium, magnesium, potassium and sodium sulfates. Calcium sulfates is the most common salt present in fine aggregate. It is usually finding as gypsum. It is difficult to obtain the specific sulfates content in fine aggregate within standard specifications. This research was conducted to investigate the effect of adding different contents of gypsum to fine aggregate as a replacement by weight on some properties of two types of concrete {self-compacted concrete (SCC) and high strength concrete (HSC)}. In these work three bases mixes of each type of concrete are used: mixes with different contents of metakaolin, mixes with different contents of gypsum and mixes incorporating different contents of metakaolin and gypsum. This study is devoted to determine the allowable content of sulfates in fine aggregate. Three levels of gypsum were tested (0.5, 1, 1.5) % by weight of fine aggregate and three levels of metakaolin were tested (5, 10, 15) % by the weight of cement. The experimental program is devoted to produce concrete with different levels of metakaolin and gypsum and determine its mechanical properties such as compressive strength and splitting tensile strength. The results arrived from this work show that the optimum gypsum content was 1.5% by weight of fine aggregates for mixes of SCC which gives increases in compressive strength and tensile strength, and 1% gypsum for mixes of HSC, results showed also that the metakaolin improved the properties of the two types of concrete and increased the loss which caused by sulfates. The best mix ever in SCC is 1% gypsum with 5% metakaolin, and 1% gypsum with 10% metakaolin for HSC

The impact of the Covid-19 pandemic on adult diagnostic neuroradiology in Europe

PURPOSE: The purpose of this survey was to understand the impact the Covid-19 pandemic has or has had on the work, training, and wellbeing of professionals in the field of diagnostic neuroradiology. METHODS: A survey was emailed to all ESNR members and associates as well as distributed via professional social media channels. The survey was held in the summer of 2020 when the first wave had subsided in most of Europe, while the second wave was not yet widespread. The questionnaire featured a total of 46 questions on general demographics, the various phases of the healthcare crisis, and the numbers of Covid-19 patients. RESULTS: One hundred sixty-seven responses were received from 48 countries mostly from neuroradiologists (72%). Most commonly taken measures during the crisis phase were reduction of outpatient exams (87%), reduction of number of staff present in the department (83%), reporting from home (62%), and shift work (54%). In the exit phase, these measures were less frequently applied, but reporting from home was still frequent (33%). However, only 22% had access to a fully equipped work station at home. While 81% felt safe at work during the crisis, fewer than 50% had sufficient personal protection equipment for the duration of the entire crisis. Mental wellbeing is an area of concern, with 61% feeling (much) worse than usual. Many followed online courses/congresses and considered these a viable alternative for the future. CONCLUSION: The Covid-19 pandemic substantially affected the professional life as well as personal wellbeing of neuroradiologists

MRI and pathology correlations in the medulla in SUDEP: A post-mortem study

Aims: Sudden unexpected death in epilepsy (SUDEP) likely arises as a result of autonomic dysfunction around the time of a seizure. In vivo MRI studies report volume reduction in the medulla and other brainstem autonomic regions. Our aim, in a pathology series, is to correlate regional quantitative features on 9.4T MRI with pathology measures in medullary regions. Methods: Forty‐seven medullae from 18 SUDEP, 18 nonepilepsy controls and 11 epilepsy controls were studied. In 16 cases, representing all three groups, ex vivo 9.4T MRI of the brainstem was carried out. Five regions of interest (ROI) were delineated, including the reticular formation zone (RtZ), and actual and relative volumes (RV), as well as T1, T2, T2* and magnetization transfer ratio (MTR) measurements were evaluated on MRI. On serial sections, actual and RV estimates using Cavalieri stereological method and immunolabelling indices for myelin basic protein, synaptophysin and Microtubule associated protein 2 (MAP2) were carried out in similar ROI. Results: Lower relative RtZ volumes in the rostral medulla but higher actual volumes in the caudal medulla were observed in SUDEP (P < 0.05). No differences between groups for T1, T2, T2* and MTR values in any region was seen but a positive correlation between T1 values and MAP2 labelling index in RtZ (P < 0.05). Significantly lower MAP2 LI were noted in the rostral medulla RtZ in epilepsy cases (P < 0.05). Conclusions: Rostro‐caudal alterations of medullary volume in SUDEP localize with regions containing respiratory regulatory nuclei. They may represent seizure‐related alterations, relevant to the pathophysiology of SUDEP

Muscle "islands": an MRI signature distinguishing neurogenic from myopathic causes of early onset distal weakness

Muscle MRI has an increasing role in diagnosis of inherited neuromuscular diseases, but no features are known which reliably differentiate myopathic and neurogenic conditions. Using patients presenting with early onset distal weakness, we aimed to identify an MRI signature to distinguish myopathic and neurogenic conditions. We identified lower limb MRI scans from patients with either genetically (n=24) or clinically (n=13) confirmed diagnoses of childhood onset distal myopathy or distal spinal muscular atrophy. An initial exploratory phase reviewed 11 scans from genetically confirmed patients identifying a single potential discriminatory marker concerning the pattern of fat replacement within muscle, coined “islands”. This pattern comprised small areas of muscle tissue with normal signal intensity completely surrounded by areas with similar intensity to subcutaneous fat. In the subsequent validation phase, islands correctly classified scans from all 12 remaining genetically confirmed patients, and 12/13 clinically classified patients. In the genetically confirmed patients MRI classification of neurogenic/myopathic aetiology had 100% accuracy (24/24) compared with 65% accuracy (15/23) for EMG, and 79% accuracy (15/19) for muscle biopsy. Future studies are needed in other clinical contexts, however the presence of islands appears to highly suggestive of a neurogenic aetiology in patients presenting with early onset distal motor weakness