Nonlocal Second-Order Geometric Equations Arising in Tomographic Reconstruction

In this paper, we study a new model of nonlocal geometric equations which appears in tomographic reconstruction when using the level-set method. We treat two additional difficulties which make the work original. On one hand, the level lines do not evolve along normal directions, and the nonlocal term is not of "convolution type". On the other hand, the speed is not necessarily bounded compared to the nonlocal term. We prove a existence and uniqueness results of our model.Comment: 22 page

The Multigeneic _Rhg1_ Locus: A Model For The Effects on Root Development, Nematode Resistance and Recombination Suppression.

Soybean (Glycine max L. Merr.) resistance to populations (HgType) of _Heterodera glycines I._, the soybean cyst nematode (SCN), requires a functional allele at rhg1. An apoptosis-like response in the giant cells formed around the nematode results 24-48 h after feeding commences. This study aimed to identify the role of the three genes within the rhg1 locus, a receptor like kinase (RLK), a laccase and an ion anti-porter. Used were near isogeneic lines (NILs) that contrasted at their rhg1 alleles. Features of the rhg1 locus, the candidate genes and their nascent transcripts and proteins in roots were elucidated. First, evidence for a syntenic gene cluster was found and the effectiveness of SNP probes for distinguishing the homeolog sequence variant on linkage group (Lg) B1 from alleles at the rhg1 locus on Lg G was shown. Analysis of plant s heterozygous at rhg1 showed that the allele for resistance was dominant. The absence of recombination events among the NILs between the RLK and other 2 genes eliminated the possibility of a monogeneic rhg1 locus. Finally, an effect on root development was discovered. A model for multigeneic resistance based on developmental control of root growth including a mechanism for segregation distortion is presented

Critical Impact of Social Networks Infodemic on Defeating Coronavirus COVID-19 Pandemic: Twitter-Based Study and Research Directions

News creation and consumption has been changing since the advent of social media. An estimated 2.95 billion people in 2019 used social media worldwide. The widespread of the Coronavirus COVID-19 resulted with a tsunami of social media. Most platforms were used to transmit relevant news, guidelines and precautions to people. According to WHO, uncontrolled conspiracy theories and propaganda are spreading faster than the COVID-19 pandemic itself, creating an infodemic and thus causing psychological panic, misleading medical advises, and economic disruption. Accordingly, discussions have been initiated with the objective of moderating all COVID-19 communications, except those initiated from trusted sources such as the WHO and authorized governmental entities. This paper presents a large-scale study based on data mined from Twitter. Extensive analysis has been performed on approximately one million COVID-19 related tweets collected over a period of two months. Furthermore, the profiles of 288,000 users were analyzed including unique users profiles, meta-data and tweets context. The study noted various interesting conclusions including the critical impact of the (1) exploitation of the COVID-19 crisis to redirect readers to irrelevant topics and (2) widespread of unauthentic medical precautions and information. Further data analysis revealed the importance of using social networks in a global pandemic crisis by relying on credible users with variety of occupations, content developers and influencers in specific fields. In this context, several insights and findings have been provided while elaborating computing and non-computing implications and research directions for potential solutions and social networks management strategies during crisis periods.Comment: 11 pages, 10 figures, Journal Articl

Water Flow-Like Algorithm with Simulated Annealing for Travelling Salesman Problems

Water Flow-like Algorithm (WFA) has been proved its ability obtaining a fast and quality solution for solving Travelling Salesman Problem (TSP). The WFA uses the insertion move with 2-neighbourhood search to get better flow splitting and moving decision. However, the algorithms can be improved by making a good balance between its solution search exploitation and exploration. Such improvement can be achieved by hybridizing good search algorithm with WFA.  This paper presents a hybrid of WFA with various three neighbourhood search in Simulated Annealing (SA) for TSP problem. The performance of the proposed method is evaluated using 18 large TSP benchmark datasets. The experimental result shows that the hybrid method has improved the solution quality compare with the basic WFA and state of art algorithm for TSP

New Approaches to Selecting Resistance or Tolerance to SDS and Fusarium Root Rot

Fusarial rots are a significant problem worldwide affecting roots (and sometimes fruits) of most major crops including soybean, maize and wheat. Cultivar variation in partial resistance or tolerance is widespread and significant. Different cultivars of the soybean [Glycine max (L.) Merr.] have both resistance/tolerance to the leaf scorch known as Sudden Death Syndrome (SDS) and to the infection and root rot by the causal organism, Fusarium virguliforme (ex. F. solani f. sp glycines) hence the syndrome is composed of two diseases (1-3). Thirteen loci have been identified from analysis of 7 different crosses (2). Using new strains and new methods resistance loci in ‘Hartwig’ and ‘Forrest’, resistant cultivars clearly showed two loci underlie root resistance (lower LG G and D2) and four to eleven loci underlie leaf scorch resistance, depending on the cross made(eg, C2, F, I and upper G in ExF). Transcript abundance analysis of roots in response to F. virguliforme shows an orthologous set of transcripts accumulate during infection of resistant soybean cultivars and Arabidopsis thaliana that include the pathways leading to phenylpropanoid metabolism and its control, guanyl cylase a common second messenger and several transcription factors. Guanyl cyclase is also implicated in resistance in maize. In root disease resistance the genes implicated were known to be stress related. Therefore, A. thaliana is partially resistant and can be used to test both transgenes and mutants in candidate genes. Trangenics show fine maps to BACs have isolated some genes. For example, by fine mapping in NILs candidate genes underlying the controlling loci programming root resistance was a multi-stress resistance protein (lower G; Rfs1). For leaf scorch (Rfs4) an ascorbate peroxidase (C2) has been targeted. Also, Rfs2, a receptor like kinase (G) has been used to generate stable transgenic soybeans. Identification of the genes and loci conferring SDS resistance has provided options to breed improved cultivars with resistance to SDS

Resistance to Soybean Cyst Nematode: Rhg1

The genes underlying rhg1 lie at a sometimes dominant sometimes co-dominant locus, necessary for resistance to all Hg types of the soybean (Glycine max (L.) Merr.) cyst nematode (Heterodera glycines). Genomic research identified; nucleotide changes within a candidate gene encoding a receptor like kinase (RLK) that were capable of altering root development and thereby part of the resistance to Hg types 0 (race 3); changes in a laccase that are capable of altering cyst development; and genes underlying changes in membrane biology. This set of three genes are subject to co-selection with a modifier locus on another linkage block. Root development is slowed in the resistant seedling and results in end of season yield loss when SCN is not present. However, in the presence of SCN resistant seedling roots grow just as vigorously as the now slower growing parasitized susceptible roots and therefore show little loss to SCN parasitism. In some genotypes but not others the RLK can act alone to confer resistance. Functional paralogs of the three gene cluster have been found on other linkage groups including A1, B1, G, and O and these can be functional in different sources of resistance like G. soja, PI 437654 and PI438489B. At rhg1 the allele differences change the structure, interacting partners and activity of the LRR protein and the laccase. The changes between the alleles result in about 30 other proteins (judged by 2 D gels), 112 metabolites (by FTICRMS) and 8 metabolites (by GCMS) to increase in abundance in roots during SCN infection in the resistant NILs. Understanding the basis of root stunting by resistance alleles will be used to improve methods for developing new nematode resistant soybean cultivars that do not suffer from the yield suppression and low seed germination rates of existing cultivars

Homo-dimerization and ligand binding by the leucine-rich repeat domain at RHG1/RFS2 underlying resistance to two soybean pathogens

BACKGROUND: The protein encoded by GmRLK18-1 (Glyma_18_02680 on chromosome 18) was a receptor like kinase (RLK) encoded within the soybean (Glycine max L. Merr.) Rhg1/Rfs2 locus. The locus underlies resistance to the soybean cyst nematode (SCN) Heterodera glycines (I.) and causal agent of sudden death syndrome (SDS) Fusarium virguliforme (Aoki). Previously the leucine rich repeat (LRR) domain was expressed in Escherichia coli. RESULTS: The aims here were to evaluate the LRRs ability to; homo-dimerize; bind larger proteins; and bind to small peptides. Western analysis suggested homo-dimers could form after protein extraction from roots. The purified LRR domain, from residue 131–485, was seen to form a mixture of monomers and homo-dimers in vitro. Cross-linking experiments in vitro showed the H274N region was close (<11.1 A) to the highly conserved cysteine residue C196 on the second homo-dimer subunit. Binding constants of 20–142 nM for peptides found in plant and nematode secretions were found. Effects on plant phenotypes including wilting, stem bending and resistance to infection by SCN were observed when roots were treated with 50 pM of the peptides. Far-Western analyses followed by MS showed methionine synthase and cyclophilin bound strongly to the LRR domain. A second LRR from GmRLK08-1 (Glyma_08_g11350) did not show these strong interactions. CONCLUSIONS: The LRR domain of the GmRLK18-1 protein formed both a monomer and a homo-dimer. The LRR domain bound avidly to 4 different CLE peptides, a cyclophilin and a methionine synthase. The CLE peptides GmTGIF, GmCLE34, GmCLE3 and HgCLE were previously reported to be involved in root growth inhibition but here GmTGIF and HgCLE were shown to alter stem morphology and resistance to SCN. One of several models from homology and ab-initio modeling was partially validated by cross-linking. The effect of the 3 amino acid replacements present among RLK allotypes, A87V, Q115K and H274N were predicted to alter domain stability and function. Therefore, the LRR domain of GmRLK18-1 might underlie both root development and disease resistance in soybean and provide an avenue to develop new variants and ligands that might promote reduced losses to SCN

Measurable residual disease, FLT3-ITD mutation, and disease status have independent prognostic influence on outcome of allogeneic stem cell transplantation in NPM1-mutated acute myeloid leukemia

Nucleophosmin-1 (NPM1) mutations in acute myeloid leukemia (AML) confer a survival advantage in the absence of FLT3-internal tandem duplication (FLT3-ITD). Here, we investigated the main predictors of outcome after allogeneic hematopoietic stem cell transplantation (allo-HCT). We identified 1572 adult (age &gt;= 18 year) patients with NPM1-mutated AML in first complete remission (CR1:78%) or second complete remission (CR2:22%) who were transplanted from matched sibling donors (30.8%) or unrelated donors (57.4%) between 2007 and 2019 at EBMT participating centers. Median follow-up for survivors was 23.7 months. FLT3-ITD was present in 69.3% of patients and 39.2% had detectable minimal/measurable residual disease (MRD) at transplant. In multivariate analysis, relapse incidence (RI) and leukemia-free survival (LFS) were negatively affected by concomitant FLT3-ITD mutation (HR 1.66 p = 0.0001, and HR 1.53, p &lt; 0.0001, respectively), MRD positivity at transplant (HR 2.18, p &lt; 10(-5) and HR 1.71, p &lt; 10(-5), respectively), and transplant in CR2 (HR 1.36, p = 0.026, and HR 1.26, p = 0.033, respectively), but positively affected by Karnofsky score &gt;= 90 (HR 0.74, p = 0.012, and HR 0.7, p = 0.0002, respectively). Overall survival (OS) was also negatively influenced by concomitant FLT3-ITD (HR 1.6, p = 0.0001), MRD positivity at transplant (HR 1.61, p &lt; 10(-5)), and older age (HR 1.22 per 10 years, p &lt; 0.0001), but positively affected by matched sibling donor (unrelated donor: HR 1.35, p = 0.012; haploidentical donor: HR 1.45, p = 0.037) and Karnofsky score &gt;= 90 (HR 0.73, p = 0.004). These results highlight the independent and significant role of FLT3-ITD, MRD status, and disease status on posttransplant outcomes in patients with NPM1-mutated AML allowing physicians to identify patients at risk of relapse who may benefit from posttransplant prophylactic interventions.</p

The state of HRM in the Middle East:Challenges and future research agenda

Based on a robust structured literature analysis, this paper highlights the key developments in the field of human resource management (HRM) in the Middle East. Utilizing the institutional perspective, the analysis contributes to the literature on HRM in the Middle East by focusing on four key themes. First, it highlights the topical need to analyze the context-specific nature of HRM in the region. Second, via the adoption of a systematic review, it highlights state of development in HRM in the research analysis set-up. Third, the analysis also helps to reveal the challenges facing the HRM function in the Middle East. Fourth, it presents an agenda for future research in the form of research directions. While doing the above, it revisits the notions of “universalistic” and “best practice” HRM (convergence) versus “best-fit” or context distinctive (divergence) and also alternate models/diffusion of HRM (crossvergence) in the Middle Eastern context. The analysis, based on the framework of cross-national HRM comparisons, helps to make both theoretical and practical implications

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p&lt;0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p&lt;0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised