Global stability of discrete-time competitive population models

We develop practical tests for the global stability of interior fixed points for discrete-time competitive population models. Our method constitutes the extension to maps of the Split Lyapunov method developed for differential equations. We give ecologically-motivated sufficient conditions for global stability of an interior fixed point of a competitive map of Kolmogorov form, and show how these conditions can simplify when a carrying simplex is known to exist. We introduce the concept of a principal reproductive mode, which is linked to a left eigenvector for the dominant eigenvalue of a positive matrix, which in turn is linked to a normal vector, at an interior fixed point, to a hypersurface of vanishing weighted-average growth, and also to a normal to the carrying simplex when present. A connection with permanence is also discussed. As examples of applications, we first take two well-understood planar models, namely the Leslie-Gower and the May-Oster models, where our method confirms global stability results that have previously been established, through, for example, properties of monotone maps. We also apply our methods to establish new global stability results for 3-species competitive systems of May-Leonard type, giving detailed descriptions of the parameter ranges for which the models have globally stable interior fixed points

First detection of small hive beetle Aethina tumida Murray (Coleoptera: Nitidulidae) infesting eastern honeybee, Apis cerana Fabricius (Hymenoptera: Apidae), in China

We report the infestation of small hive beetle, Aethina tumida, in a honeybee, Apis cerana, in South China. This is the first record for domestic Chinese honey bee infested with small hive beetle

(E)-N′-(5-Chloro-2-hydroxy­benzyl­idene)-3,5-dihydroxy­benzohydrazide mono­hydrate

In the title compound, C14H11ClN2O4·H2O, the dihedral angle between the two benzene rings is 8.5 (2)° and an intra­molecular O—H⋯N hydrogen bond is observed in the Schiff base mol­ecule. In the crystal structure, the water mol­ecule accepts an N—H⋯O hydrogen bond and makes O—H⋯O hydrogen bonds to two further Schiff base mol­ecules. Further inter­molecular O—H⋯O hydrogen bonds lead to the formation of layers parallel to the bc plane

Frailty, delirium and hospital mortality of older adults admitted to intensive care : the Delirium (Deli) in ICU study

Background: Clinical frailty among older adults admitted to intensive care has been proposed as an important determinant of patient outcomes. Among this group of patients, an acute episode of delirium is also common, but its relationship to frailty and increased risk of mortality has not been extensively explored. Therefore, the aim of this study was to explore the relationship between clinical frailty, delirium and hospital mortality of older adults admitted to intensive care. Methods: This study is part of a Delirium in Intensive Care (Deli) Study. During the initial 6-month baseline period, clinical frailty status on admission to intensive care, among adults aged 50 years or more; acute episodes of delirium; and the outcomes of intensive care and hospital stay were explored. Results: During the 6-month baseline period, 997 patients, aged 50 years or more, were included in this study. The average age was 71 years (IQR, 63–79); 55% were male (n = 537). Among these patients, 39.2% (95% CI 36.1–42.3%, n = 396) had a Clinical Frailty Score (CFS) of 5 or more, and 13.0% (n = 127) had at least one acute episode of delirium. Frail patients were at greater risk of an episode of delirium (17% versus 10%, adjusted rate ratio (adjRR) = 1.71, 95% confidence interval (CI) 1.20–2.43, p = 0.003), had a longer hospital stay (2.6 days, 95% CI 1–7 days, p = 0.009) and had a higher risk of hospital mortality (19% versus 7%, adjRR = 2.54, 95% CI 1.72–3.75, p < 0.001), when compared to non-frail patients. Patients who were frail and experienced an acute episode of delirium in the intensive care had a 35% rate of hospital mortality versus 10% among non-frail patients who also experienced delirium in the ICU. Conclusion: Frailty and delirium significantly increase the risk of hospital mortality. Therefore, it is important to identify patients who are frail and institute measures to reduce the risk of adverse events in the ICU such as delirium and, importantly, to discuss these issues in an open and empathetic way with the patient and their families

Multiplex quantitative PCR for single-reaction genetically modified (GM) plant detection and identification of false-positive GM plants linked to Cauliflower mosaic virus (CaMV) infection.

BACKGROUND:Most genetically modified (GM) plants contain a promoter, P35S, from the plant virus, Cauliflower mosaic virus (CaMV), and many have a terminator, TNOS, derived from the bacterium, Agrobacterium tumefaciens. Assays designed to detect GM plants often target the P35S and/or TNOS DNA sequences. However, because the P35S promoter is derived from CaMV, these detection assays can yield false-positives from non-GM plants infected by this naturally-occurring virus. RESULTS:Here we report the development of an assay designed to distinguish CaMV-infected plants from GM plants in a single multiplexed quantitative PCR (qPCR) reaction. Following initial testing and optimization via PCR and singleplex-to-multiplex qPCR on both plasmid and plant DNA, TaqMan qPCR probes with different fluorescence wavelengths were designed to target actin (a positive-control plant gene), P35S, P3 (a CaMV-specific gene), and TNOS. We tested the specificity of our quadruplex qPCR assay using different DNA extracts from organic watercress and both organic and GM canola, all with and without CaMV infection, and by using commercial and industrial samples. The limit of detection (LOD) of each target was determined to be 1% for actin, 0.001% for P35S, and 0.01% for both P3 and TNOS. CONCLUSIONS:This assay was able to distinguish CaMV-infected plants from GM plants in a single multiplexed qPCR reaction for all samples tested in this study, suggesting that this protocol is broadly applicable and readily transferrable to any interested parties with a qPCR platform

The pestivirus N terminal protease N(pro) redistributes to mitochondria and peroxisomes suggesting new sites for regulation of IRF3 by N(pro.)

The N-terminal protease of pestiviruses, N(pro) is a unique viral protein, both because it is a distinct autoprotease that cleaves itself from the following polyprotein chain, and also because it binds and inactivates IRF3, a central regulator of interferon production. An important question remains the role of N(pro) in the inhibition of apoptosis. In this study, apoptotic signals induced by staurosporine, interferon, double stranded RNA, sodium arsenate and hydrogen peroxide were inhibited by expression of wild type N(pro), but not by mutant protein N(pro) C112R, which we show is less efficient at promoting degradation of IRF3, and led to the conclusion that N(pro) inhibits the stress-induced intrinsic mitochondrial pathway through inhibition of IRF3-dependent Bax activation. Both expression of N(pro) and infection with Bovine Viral Diarrhea Virus (BVDV) prevented Bax redistribution and mitochondrial fragmentation. Given the role played by signaling platforms during IRF3 activation, we have studied the subcellular distribution of N(pro) and we show that, in common with many other viral proteins, N(pro) targets mitochondria to inhibit apoptosis in response to cell stress. N(pro) itself not only relocated to mitochondria but in addition, both N(pro) and IRF3 associated with peroxisomes, with over 85% of N(pro) puncta co-distributing with PMP70, a marker for peroxisomes. In addition, peroxisomes containing N(pro) and IRF3 associated with ubiquitin. IRF3 was degraded, whereas N(pro) accumulated in response to cell stress. These results implicate mitochondria and peroxisomes as new sites for IRF3 regulation by N(pro), and highlight the role of these organelles in the anti-viral pathway

Locked Nucleic Acid Pentamers as Universal PCR Primers for Genomic DNA Amplification

Background: Multiplexing technologies, which allow for simultaneous detection of multiple nucleic acid sequences in a single reaction, can save a lot of time, cost and labor compared to traditional single reaction detection methods. However, the multiplexing method currently used requires precise handiwork and many complicated steps, making a new, simpler technique desirable. Oligonucleotides containing locked nucleic acid residues are an attractive tool because they have strong affinities for their complementary targets, they have been used to avoid dimer formation and mismatch hybridization and to enhance efficient priming. In this study, we aimed to investigate the use of locked nucleic acid pentamers for genomic DNA amplification and multiplex genotyping. Results: We designed locked nucleic acid pentamers as universal PCR primers for genomic DNA amplification. The locked nucleic acid pentamers were able to prime amplification of the selected sequences within the investigated genomes, and the resulting products were similar in length to those obtained by restriction digest. In Real Time PCR of genomic DNA from three bacterial species, locked nucleic acid pentamers showed high priming efficiencies. Data from bias tests demonstrated that locked nucleic acid pentamers have equal affinities for each of the six genes tested from the Klebsiella pneumoniae genome. Combined with suspension array genotyping, locked nucleic acid pentamer-based PCR amplification was able to identify a total of 15 strains, including 3 species of bacteria, by gene- and species-specific probes. Among the 32 specie

Development of Photonic Crystal Fiber Based Gas/ Chemical Sensors

The development of highly-sensitive and miniaturized sensors that capable of real-time analytes detection is highly desirable. Nowadays, toxic or colorless gas detection, air pollution monitoring, harmful chemical, pressure, strain, humidity, and temperature sensors based on photonic crystal fiber (PCF) are increasing rapidly due to its compact structure, fast response and efficient light controlling capabilities. The propagating light through the PCF can be controlled by varying the structural parameters and core-cladding materials, as a result, evanescent field can be enhanced significantly which is the main component of the PCF based gas/chemical sensors. The aim of this chapter is to (1) describe the principle operation of PCF based gas/ chemical sensors, (2) discuss the important PCF properties for optical sensors, (3) extensively discuss the different types of microstructured optical fiber based gas/ chemical sensors, (4) study the effects of different core-cladding shapes, and fiber background materials on sensing performance, and (5) highlight the main challenges of PCF based gas/ chemical sensors and possible solutions

A statistical model for the identification of genes governing the incidence of cancer with age

The cancer incidence increases with age. This epidemiological pattern of cancer incidence can be attributed to molecular and cellular processes of individual subjects. Also, the incidence of cancer with ages can be controlled by genes. Here we present a dynamic statistical model for explaining the epidemiological pattern of cancer incidence based on individual genes that regulate cancer formation and progression. We incorporate the mathematical equations of age-specific cancer incidence into a framework for functional mapping aimed at identifying quantitative trait loci (QTLs) for dynamic changes of a complex trait. The mathematical parameters that specify differences in the curve of cancer incidence among QTL genotypes are estimated within the context of maximum likelihood. The model provides testable quantitative hypotheses about the initiation and duration of genetic expression for QTLs involved in cancer progression. Computer simulation was used to examine the statistical behavior of the model. The model can be used as a tool for explaining the epidemiological pattern of cancer incidence