Chitosan and chitosan nanoparticles differentially alleviate salinity stress in Phaseolus vulgaris L. plants

Salinity stress can significantly cause negative impacts on the physiological and biochemical traits of plants and, consequently, a reduction in the yield productivity of crops. Therefore, the current study aimed to investigate the effects of chitosan (Cs) and chitosan nanoparticles (CsNPs) to mitigate salinity stress (i.e., 25, 50, 100, and 200 mM NaCl) and improve pigment fractions, carbohydrates content, ions content, proline, hydrogen peroxide, lipid peroxidation, electrolyte leakage content, and the antioxidant system of Phaseolus vulgaris L. grown in clay–sandy soil. Methacrylic acid was used to synthesize CsNPs, with an average size of 40 ± 2 nm. Salinity stress negatively affected yield traits, pigment fractions, and carbohydrate content. However, in plants grown under salt stress, the application of either Cs or CsNPs significantly improved yield, pigment fractions, carbohydrate content, proline, and the antioxidant system, while these treatments reduced hydrogen peroxide, lipid peroxidation, and electrolyte leakage. The positive effects of CsNPs were shown to be more beneficial than Cs when applied exogenously to plants grown under salt stress. In this context, it could be concluded that CsNPs could be used to mitigate salt stress effects on Phaseolus vulgaris L. plants grown in saline soils

Mobile ad hoc network testbed using mobile robot technology

MANET (Mobile Ad Hoc Network) researchers have shown increased interest in using mobile robot technology for their testbed platforms. Thus, the main motivation of this paper is to review various robot-based MANET testbeds that have been developed in previously reported research. Additionally, suggestions to heighten mobility mechanisms by using mobile robots to be more practical, easy and inexpensive are also included in this paper, as we unveils ToMRobot, a low-cost MANET robot created from an ordinary remote control car that is capable of performing a real system MANET testbed with the addition of only a few low-cost electronic components. Despite greatly reduced costs, the ToMRobot does not sacrifice any of the necessary MANET basic structures and will still be easily customizable and upgradeable through the use of open hardware technology like Cubieboard2 and Arduino, as its robot controller. This paper will also include guidelines to enable technically limited MANET researchers to design and develop the ToMRobot. It is hoped that this paper achieves its two pronged objectives namely (i) to facilitate other MANET researchers by providing them with a source of reference that eases their decision making for selecting the best and most suitable MANET mobile robots for real mobility in their MANET testbeds (ii) to provide MANET researchers with a prospect of building their own MANET robots that can be applied in their own MANET testbed in the future

Dark Matter in 3D

We discuss the relevance of directional detection experiments in the post-discovery era and propose a method to extract the local dark matter phase space distribution from directional data. The first feature of this method is a parameterization of the dark matter distribution function in terms of integrals of motion, which can be analytically extended to infer properties of the global distribution if certain equilibrium conditions hold. The second feature of our method is a decomposition of the distribution function in moments of a model independent basis, with minimal reliance on the ansatz for its functional form. We illustrate our method using the Via Lactea II N-body simulation as well as an analytical model for the dark matter halo. We conclude that O(1000) events are necessary to measure deviations from the Standard Halo Model and constrain or measure the presence of anisotropies.Comment: 36 pages, 13 figure

Global epidemiology and clinical outcomes of carbapenem-resistant Pseudomonas aeruginosa and associated carbapenemases (POP): a prospective cohort study

BACKGROUND: Carbapenem-resistant Pseudomonas aeruginosa (CRPA) is a global threat, but the distribution and clinical significance of carbapenemases are unclear. The aim of this study was to define characteristics and outcomes of CRPA infections and the global frequency and clinical impact of carbapenemases harboured by CRPA. METHODS: We conducted an observational, prospective cohort study of CRPA isolated from bloodstream, respiratory, urine, or wound cultures of patients at 44 hospitals (10 countries) between Dec 1, 2018, and Nov 30, 2019. Clinical data were abstracted from health records and CRPA isolates were whole-genome sequenced. The primary outcome was 30-day mortality from the day the index culture was collected. We compared outcomes of patients with CRPA infections by infection type and across geographic regions and performed an inverse probability weighted analysis to assess the association between carbapenemase production and 30-day mortality. FINDINGS: We enrolled 972 patients (USA n=527, China n=171, south and central America n=127, Middle East n=91, Australia and Singapore n=56), of whom 581 (60%) had CRPA infections. 30-day mortality differed by infection type (bloodstream 21 [30%] of 69, respiratory 69 [19%] of 358, wound nine [14%] of 66, urine six [7%] of 88; p=0·0012) and geographical region (Middle East 15 [29%] of 52, south and central America 20 [27%] of 73, USA 60 [19%] of 308, Australia and Singapore three [11%] of 28, China seven [6%] of 120; p=0·0002). Prevalence of carbapenemase genes among CRPA isolates also varied by region (south and central America 88 [69%] of 127, Australia and Singapore 32 [57%] of 56, China 54 [32%] of 171, Middle East 27 [30%] of 91, USA ten [2%] of 527; p\u3c0·0001). KPC-2 (n=103 [49%]) and VIM-2 (n=75 [36%]) were the most common carbapenemases in 211 carbapenemase-producing isolates. After excluding USA patients, because few US isolates had carbapenemases, patients with carbapenemase-producing CRPA infections had higher 30-day mortality than those with non-carbapenemase-producing CRPA infections in both unadjusted (26 [22%] of 120 vs 19 [12%] of 153; difference 9%, 95% CI 3-16) and adjusted (difference 7%, 95% CI 1-14) analyses. INTERPRETATION: The emergence of different carbapenemases among CRPA isolates in different geographical regions and the increased mortality associated with carbapenemase-producing CRPA infections highlight the therapeutic challenges posed by these organisms. FUNDING: National Institutes of Health

Epidemiología mundial y resultados clínicos de Pseudomonas aeruginosa resistente a carbapenemes y carbapenemasas asociadas (POP): un estudio prospectivo de cohortes

Antecedentes: La Pseudomonas aeruginosa resistente a los carbapenemes (CRPA) es una amenaza mundial, pero la distribución y la importancia clínica de las carbapenemasas no están claras. El objetivo de este estudio fue definir las características y los resultados de las infecciones por CRPA, así como la frecuencia global y el impacto clínico de las carbapenemasas albergadas por CRPA. Métodos: Llevamos a cabo un estudio de cohortes observacional y prospectivo de CRPA aislados de cultivos de torrente sanguíneo, respiratorio, orina o heridas de pacientes en 44 hospitales (10 países) entre el 1 de diciembre de 2018 y el 30 de noviembre de 2019. Los datos clínicos se extrajeron de los registros de salud y los aislados de CRPA se secuenciaron en todo el genoma. El resultado primario fue la mortalidad a 30 días a partir del día en que se recolectó el cultivo índice. Se compararon los resultados de los pacientes con infecciones por CRPA por tipo de infección y entre regiones geográficas y se realizó un análisis ponderado de probabilidad inversa para evaluar la asociación entre la producción de carbapenemasas y la mortalidad a 30 días. Resultados: Se incluyeron 972 pacientes (EE.UU. n=527, China n=171, América del Sur y Central n=127, Oriente Medio n=91, Australia y Singapur n=56), de los cuales 581 (60%) tenían infecciones por CRPA. La mortalidad a los 30 días difería según el tipo de infección (torrente sanguíneo 21 [30%] de 69, respiratoria 69 [19%] de 358, herida nueve [14%] de 66, orina seis [7%] de 88; p=0-0012) y la región geográfica (Oriente Medio 15 [29%] de 52, América del Sur y Central 20 [27%] de 73, EE.UU. 60 [19%] de 308, Australia y Singapur tres [11%] de 28, China siete [6%] de 120; p=0-0002). La prevalencia de genes carbapenemasa entre los aislados CRPA también varió según la región (América del Sur y Central 88 [69%] de 127, Australia y Singapur 32 [57%] de 56, China 54 [32%] de 171, Oriente Medio 27 [30%] de 91, EE.UU. diez [2%] de 527; p<0-0001). KPC-2 (n=103 [49%]) y VIM-2 (n=75 [36%]) fueron las carbapenemasas más comunes en 211 aislados productores de carbapenemasas. Después de excluir a los pacientes de EE.UU., porque pocos aislados de EE.UU. tenían carbapenemasas, los pacientes con infecciones por CRPA productoras de carbapenemasas tuvieron una mayor mortalidad a los 30 días que aquellos con infecciones por CRPA no productoras de carbapenemasas, tanto en los análisis no ajustados (26 [22%] de 120 frente a 19 [12%] de 153; diferencia 9%, IC 95% 3-16) como ajustados (diferencia 7%, IC 95% 1-14). Interpretación: La aparición de diferentes carbapenemasas entre los aislados de CRPA en diferentes regiones geográficas y el aumento de la mortalidad asociada a las infecciones por CRPA productores de carbapenemasas ponen de manifiesto los retos terapéuticos que plantean estos organismos. Financiación: Institutos Nacionales de Salud.Background: Carbapenem-resistant Pseudomonas aeruginosa (CRPA) is a global threat, but the distribution and clinical significance of carbapenemases are unclear. The aim of this study was to define characteristics and outcomes of CRPA infections and the global frequency and clinical impact of carbapenemases harboured by CRPA. Methods: We conducted an observational, prospective cohort study of CRPA isolated from bloodstream, respiratory, urine, or wound cultures of patients at 44 hospitals (10 countries) between Dec 1, 2018, and Nov 30, 2019. Clinical data were abstracted from health records and CRPA isolates were whole-genome sequenced. The primary outcome was 30-day mortality from the day the index culture was collected. We compared outcomes of patients with CRPA infections by infection type and across geographic regions and performed an inverse probability weighted analysis to assess the association between carbapenemase production and 30-day mortality. Findings: We enrolled 972 patients (USA n=527, China n=171, south and central America n=127, Middle East n=91, Australia and Singapore n=56), of whom 581 (60%) had CRPA infections. 30-day mortality differed by infection type (bloodstream 21 [30%] of 69, respiratory 69 [19%] of 358, wound nine [14%] of 66, urine six [7%] of 88; p=0·0012) and geographical region (Middle East 15 [29%] of 52, south and central America 20 [27%] of 73, USA 60 [19%] of 308, Australia and Singapore three [11%] of 28, China seven [6%] of 120; p=0·0002). Prevalence of carbapenemase genes among CRPA isolates also varied by region (south and central America 88 [69%] of 127, Australia and Singapore 32 [57%] of 56, China 54 [32%] of 171, Middle East 27 [30%] of 91, USA ten [2%] of 527; p<0·0001). KPC-2 (n=103 [49%]) and VIM-2 (n=75 [36%]) were the most common carbapenemases in 211 carbapenemase-producing isolates. After excluding USA patients, because few US isolates had carbapenemases, patients with carbapenemase-producing CRPA infections had higher 30-day mortality than those with non-carbapenemase-producing CRPA infections in both unadjusted (26 [22%] of 120 vs 19 [12%] of 153; difference 9%, 95% CI 3–16) and adjusted (difference 7%, 95% CI 1–14) analyses. Interpretation: The emergence of different carbapenemases among CRPA isolates in different geographical regions and the increased mortality associated with carbapenemase-producing CRPA infections highlight the therapeutic challenges posed by these organisms. Funding: National Institutes of Health

Survival implications vs. complications: unraveling the impact of vitamin D adjunctive use in critically ill patients with COVID-19—A multicenter cohort study

BackgroundDespite insufficient evidence, vitamin D has been used as adjunctive therapy in critically ill patients with COVID-19. This study evaluates the effectiveness and safety of vitamin D as an adjunctive therapy in critically ill COVID-19 patients.MethodsA multicenter retrospective cohort study that included all adult COVID-19 patients admitted to the intensive care units (ICUs) between March 2020 and July 2021. Patients were categorized into two groups based on their vitamin D use throughout their ICU stay (control vs. vitamin D). The primary endpoint was in-hospital mortality. Secondary outcomes were the length of stay (LOS), mechanical ventilation (MV) duration, and ICU-acquired complications. Propensity score (PS) matching (1:1) was used based on the predefined criteria. Multivariable logistic, Cox proportional hazards, and negative binomial regression analyses were employed as appropriate.ResultsA total of 1,435 patients were included in the study. Vitamin D was initiated in 177 patients (12.3%), whereas 1,258 patients did not receive it. A total of 288 patients were matched (1:1) using PS. The in-hospital mortality showed no difference between patients who received vitamin D and the control group (HR 1.22, 95% CI 0.87–1.71; p = 0.26). However, MV duration and ICU LOS were longer in the vitamin D group (beta coefficient 0.24 (95% CI 0.00–0.47), p = 0.05 and beta coefficient 0.16 (95% CI −0.01 to 0.33), p = 0.07, respectively). As an exploratory outcome, patients who received vitamin D were more likely to develop major bleeding than those who did not [OR 3.48 (95% CI 1.10, 10.94), p = 0.03].ConclusionThe use of vitamin D as adjunctive therapy in COVID-19 critically ill patients was not associated with survival benefits but was linked with longer MV duration, ICU LOS, and higher odds of major bleeding

A Comparative Study of Traffic Classification Techniques for Smart City Networks

Smart city networks involve many applications that impose specific Quality of Service (QoS) requirements, thus representing a challenging scenario for network management. Solutions aiming to guarantee QoS support have not been deployed in large-scale networks. Traffic classification is a mechanism used to manage different aspects, including QoS requirements. However, conventional traffic classification methods, such as the port-based method, are inefficient because of their inability to handle dynamic port allocation and encryption. Traffic classification using machine learning has gained research interest as an alternative method to achieve high performance. In fact, machine learning embeds intelligence into network functions, thus improving network management. In this study, we apply machine learning algorithms to predict network traffic classification. We apply four supervised learning algorithms: support vector machine, random forest, k-nearest neighbors, and decision tree. We also apply a port-based method of traffic classification based on applications’ popular assigned port numbers. Then, we compare the results of this method to those obtained from the machine learning algorithms. The evaluation results indicate that the decision tree algorithm provides the highest average accuracy among the evaluated algorithms, at 99.18%. Moreover, network traffic classification using machine learning provides more accurate results and higher performance than the port-based method

On the Fitness of Geographic Graph Generators for Modelling Physical Level Topologies

The Internet topology has been studied extensively for decades. However, the emphasis of Internet topology research has been on logical level topologies. On the other hand, physical level topologies are necessary to study the resilience of networks realistically. In this paper, we analyse the structure of synthetic geographic topologies whose node locations are given by those of actual physical level graphs. Our results indicate that the synthetic Gabriel graphs capture the grid-like structure of physical level networks. Moreover, given that the cost of physical level topologies is an important aspect from a design perspective, we also compare the cost of several synthetically generated geographic graphs and find that the synthetic Gabriel graphs achieve the smallest cost among all of the graph models that we consider

A Comparative Analysis of Geometric Graph Models For Modelling Backbone Networks

Many researchers have studied Internet topology, and the analysis of complex and multilevel Internet structure is nontrivial. The emphasis of these studies has been on logical level topologies, however physical level topologies are necessary to study resilience realistically, given the geography and multilevel nature of the Internet. In this paper, we investigate the representativeness of the synthetic Gabriel, geometric, population-weighted geographical threshold, and location-constrained Waxman graph models to the actual fibre backbone networks of six providers. We quantitatively analyse the structure of the synthetic geographic topologies whose node locations are given by those of actual physical level graphs using well-known graph metrics, graph spectra, and the visualisation tool we have developed. Our results indicate that the synthetic Gabriel graphs capture the grid-like structure of physical level networks best. Furthermore, given that the cost of physical level topologies is an important aspect from a design perspective, we also compare the cost of synthetically generated geographic graphs and find that the synthetic Gabriel graphs achieve the smallest cost among all the graph models that we consider. Finally, based on our findings we propose a graph generation method to model physical level topologies, and show that it captures both grid and star structures ideally

Multilevel Resilience Analysis of Transportation and Communication Networks

For many years the research community has attempted to model the Internet in order to better understand its behaviour and improve its performance. Since much of the structural complexity of the Internet is due to its multilevel operation, the Internet\u27s multilevel nature is an important and non-trivial feature that researchers must consider when developing appropriate models. In this paper, we compare the normalised Laplacian spectra of physical- and logical-level topologies of four commercial ISPs and two research networks against the US freeway topology, and show analytically that physical level communication networks are structurally similar to the US freeway topology. We also generate synthetic Gabriel graphs of physical topologies and show that while these synthetic topologies capture the grid-like structure of actual topologies, they are more expensive than the actual physical level topologies based on a network cost model. Moreover, we introduce a distinction between geographic graphs that include degree-2 nodes needed to capture the geographic paths along which physical links follow, and structural graphs that eliminate these degree-2 nodes and capture only the interconnection properties of the physical graph and its multilevel relationship to logical graph overlays. Furthermore, we develop a multilevel graph evaluation framework and analyse the resilience of single and multilevel graphs using the flow robustness metric. We then confirm that dynamic routing performed over the lower levels helps to improve the performance of a higher level service, and that adaptive challenges more severely impact the performance of the higher levels than non-adaptive challenges