On the non-integrability of the Popowicz peakon system

We consider a coupled system of Hamiltonian partial differential equations introduced by Popowicz, which has the appearance of a two-field coupling between the Camassa-Holm and Degasperis-Procesi equations. The latter equations are both known to be integrable, and admit peaked soliton (peakon) solutions with discontinuous derivatives at the peaks. A combination of a reciprocal transformation with Painlev\'e analysis provides strong evidence that the Popowicz system is non-integrable. Nevertheless, we are able to construct exact travelling wave solutions in terms of an elliptic integral, together with a degenerate travelling wave corresponding to a single peakon. We also describe the dynamics of N-peakon solutions, which is given in terms of an Hamiltonian system on a phase space of dimension 3N.Comment: 8 pages, AIMS class file. Proceedings of AIMS conference on Dynamical Systems, Differential Equations and Applications, Arlington, Texas, 200

Thermal evolution and structure models of the transiting super-Earth GJ 1214b

The planet GJ 1214b is the second known super-Earth with a measured mass and radius. Orbiting a quiet M-star, it receives considerably less mass-loss driving X-ray and UV radiation than CoRoT-7b, so that the interior may be quite dissimilar in composition, including the possibility of a large fraction of water. We model the interior of GJ 1214b assuming a two-layer (envelope+rock core) structure where the envelope material is either H/He, pure water, or a mixture of H/He and H2O. Within this framework we perform models of the thermal evolution and contraction of the planet. We discuss possible compositions that are consistent with Mp=6.55 ME, Rp=2.678 RE, an age tau=3-10 Gyr, and the irradiation level of the atmosphere. These conditions require that if water exists in the interior, it must remain in a fluid state, with important consequences for magnetic field generation. These conditions also require the atmosphere to have a deep isothermal region extending down to 80-800 bar, depending on composition. Our results bolster the suggestion of a metal-enriched H/He atmosphere for the planet, as we find water-world models that lack an H/He atmosphere to require an implausibly large water-to-rock ratio of more than 6:1. We instead favor a H/He/H2O envelope with high water mass fraction (~0.5-0.85), similar to recent models of the deep envelope of Uranus and Neptune. Even with these high water mass fractions in the H/He envelope, generally the bulk composition of the planet can have subsolar water:rock ratios. Dry, water-enriched, and pure water envelope models differ to an observationally significant level in their tidal Love numbers k2 of respectively ~0.018, 0.15, and 0.7.Comment: 11 pages, 6 figures, 1 table, accepted to Ap

Risk Perceptions of Arsenic in Tap Water and Consumption of Bottled Water

The demand for bottled water has increased rapidly over the past decade, but bottled water is extremely costly compared to tap water. The convenience of bottled water surely matters to consumers, but are others factors at work? This manuscript examines whether purchases of bottled water are associated with the perceived risk of tap water. All of the past studies on bottled water consumption have used simple scale measures of perceived risk that do not correspond to risk measures used by risk analysts. We elicit a probability-based measure of risk and find that as perceived risks rise, expenditures for bottled water rise.Environmental Economics and Policy, Risk and Uncertainty, Q25, Q53, I12,

Evaluation of matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) for the Identification of Group B Streptococcus.

Objective Group B Streptococcus (GBS) is a leading cause of neonatal meningitis and sepsis worldwide. Intrapartum antibiotics given to women carrying GBS are an effective means of reducing disease in the first week of life. Rapid and reliable tests are needed to accurately identify GBS from these women for timely intrapartum antibiotic administration to prevent neonatal disease. Many laboratories now use matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) by direct plating or cell lysis for the identification of GBS isolates. The cell lysis step increases time to results for clinical samples and is more complex to perform. Therefore, we seek to evaluate the sensitivity and specificity of the quicker and more rapid direct plating method in identifying GBS. Results We directly compared swab isolates analysed by both direct plating and cell lysis method and demonstrated that direct plating has a sensitivity and specificity of 0.97 and 1, respectively, compared to an additional cell lysis step. We demonstrated that MALDI-TOF MS can be successfully used for batch processing by the direct plating method which saves time. These results are reassuring for laboratories worldwide who seek to identify GBS from swabs samples as quickly as possible

Serdexmethylphenidate/Dexmethylphenidate – A Promising Treatment Option for Childhood Attention Deficit Hyperactivity Disorder (ADHD)

To review the phase 2 and phase 3 clinical trials of Serdexmethylphenidate and dexmethylphenidate (SDX/d-MPH) in the treatment of Attention Deficit/Hyperactivity disorder (ADHD) in children

IDENTIFICATION OF POTENTIAL ANTIOXIDANT AND HEPATOPROTECTIVE CONSTITUENTS OF VITEX DONIANA BY UHPLC/+ESI-QQTOF-MS/MS ANALYSIS

Objective: This study evaluated the antioxidant and hepatoprotective activities of the dichloromethane (DCM-F) and n-butanol (BUT) fractions of Vitex doniana and identified the bioactive constituents using liquid chromatography-mass spectrometry (LC-MS) analysis. Methods: The methanol extract of the leaves was subjected to liquid-liquid fractionation and the BUT soluble separated by vacuum LC (VLC) using binary mixtures of DCM in methanol (1 L) sequentially in the ratios of 9:1 BF1–1:9 BF5. The antioxidant activity was investigated in vitro using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) scavenging, phosphomolybdenum total antioxidant capacity, and ferric ion reducing antioxidant power assay methods. The in vivo antioxidant potential was performed by measuring the concentrations of both enzymatic and non-enzymatic parameters in carbon tetrachloride (CCl4)-induced hepatic injury. Results: The extract, DCM-F, and the VLC sub-fractions showed good antioxidant activity which is comparable with ascorbic acid (53.6%). DCM-F showed the highest antioxidant activity (71.6%), while the least activity was shown by BF5 (15.0%). Peak dereplication of LC-MS chromatograms identified several putative compounds in the BUT soluble. DCM-F caused a significant increase (p<0.05) in superoxide dismutase, catalase, glutathione peroxidase, and Vitamins C and E in CCl4-induced rats compared to standard. The levels of serum alkaline phosphatase, alanine aminotransferase and aspartate aminotransferase, and malondialdehyde that were elevated in CCl4-induced rats were also significantly reduced (p<0.05) by the DCM-F compared to standard. Conclusion: The ability of V. doniana leaves to mop up free radicals and reverse the CCl4-induced hepatic injury in rats suggests antioxidant potentials. The bioactive compounds identified in BUT fraction could support its ethnomedicinal uses in the treatment of illnesses associated with radical scavenging activity

Current and future opportunities for satellite remote sensing to inform rewilding

Rewilding has been suggested as an effective strategy for addressing environmental challenges such as the intertwined biodiversity and climate change crises, but there is little information to guide the monitoring of rewilding projects. Since rewilding focuses on enhancing ecosystem functionality, with no defined endpoint, monitoring strategies used in restoration are often inappropriate, as they typically focus on assessing species composition, or the ecological transition of an ecosystem towards a defined desired state. We here discuss how satellite remote sensing can provide an opportunity to address existing knowledge and data gaps in rewilding science. We first discuss how satellite remote sensing is currently being used to inform rewilding initiatives and highlight current barriers to the adoption of this type of technology by practitioners and scientists involved with rewilding. We then identify opportunities for satellite remote sensing to help address current knowledge gaps in rewilding, including gaining a better understanding of the role of animals in ecosystem functioning; improving the monitoring of landscape-scale connectivity; and assessing the impacts of rewilding on the conservation status of rewilded sites. Though significant barriers remain to the widespread use of satellite remote sensing to monitor rewilding projects, we argue that decisions on monitoring approaches and priorities need to be part of implementation plans from the start, involving both remote sensing experts and ecologists. Making use of the full potential of satellite remote sensing for rewilding ultimately requires integrating species and ecosystem perspectives at the monitoring, knowledge-producing and decision-making levels. Such an integration will require a change in know-how, necessitating increased inter-disciplinary interactions and collaborations, as well as conceptual shifts in communities and organizations traditionally involved in biodiversity conservation