The Holocene influence on the future evolution of the Venice Lagoon tidal marshes

The resilience of marsh ecosystems to expected sea-level rise is determined by a complex interplay of organic and inorganic sedimentation dynamics. Marshes have formed over past centuries to millennia and consist of extremely reactive bodies with sediments that can experience high compaction. Here we provide a quantification of the degree to which the past history of a salt marsh can affect its long-term evolution. A dataset of elevation dynamics was established in the Venice Lagoon (Italy) and interpreted using a physics-based model of deposition and large consolidation of newly deposited material. We found that the fate of low-lying tidal landscapes over the next century of accelerating sea-level rise will be highly dependent on compaction of soft, recently deposited soils. Our results imply that a sedimentation rate twice the present rate will be needed to counterbalance the expected sea-level rise.

Regulation of Membrane Phospholipid Homeostasis in Neurodegenerative Diseases

Neurodegenerative diseases (NDs) are a diverse group of neuropathological diseases that are currently incurable due to the irreversible neuronal loss. At the present rate of the world population growth, it is projected that the number of ND cases will double by the year of 2050. With treatments only available for symptom management and relief, disease prevention may yield significant benefits. Recently, there had been association drawn between the disruption of phospholipid (PL) homeostasis and the progression of NDs. Pathological developments were observed in cellular processes including autophagy, maintenance of mitochondrial integrity, and management of tissue oxidative stress. As PLs actively participate in the regulation of these cellular pathways and in neuronal signal transduction for the maintenance of an optimally functioning nervous system, their homeostasis is tightly controlled via an intricate system of interconversion and metabolism. Therefore, in this review, the contribution of a homeostatic PL pool and the detrimental effects by the lack thereof, are discussed in detail as it relates to ND development.

Preliminary results of land subsidence monitoring in the Ca Mau Province

A previous study of the Ca Mau province in Vietnam (Karlsrud et al., 2017a) suggested that ongoing groundwater pumping, which by 2012 had caused a drawdown of the water level in aquifers of up to 20 m, caused subsidence of the order 2–4 cm yr−1, and could have reached over 40 cm already. Earlier InSAR studies also suggested ongoing subsidence rates of that order. If the groundwater pumping continues, the total subsidence could reach well over 1 m within the next few decades. The predicted climate driven sea level rise, to be of the order of 60 cm by 2100, will further add to the severe effect of the subsidence. As most of the Ca Mau province lies only 0.5 to 1.5 m a.s.l. (above sea level), the consequences would rapidly become very serious for the livelihood of people in the region. Increased saltwater intrusion into canals and tributaries in the province, and beginning salination of some of the aquifers from which groundwater is pumped, is already observed. In 2017, for the first time, a physical system for subsidence monitoring was installed at three selected locations in the Ca Mau province. At each location a deep benchmark to a depth of 100 m was installed, each with 3 piezometers at depths ranging from 15 to 60 m. An InSAR corner reflector was also installed at each site. The paper presents data collected from these new monitoring stations up until the middle 2019. When including estimated subsidence stemming from the soil levels deeper than 100 m, the total present rate of subsidence at the three new monitoring stations range from 17 to 44 mm yr−1. New and previous data show an almost linear decrease in water level within the aquifers from which groundwater is pumped. The data show some seasonal variations in subsidence rates, which is also reflected in variations in pore pressures in the sediments. Such variations are probably related to seasonal variations in levels of groundwater pumping. It is feared that many of the other provinces south of Ho Chi Minh city, face similar subsidence problems. The monitoring program should be extended to verify that. Measures to reduce groundwater and subsidence are urgently needed.

Modeling the OH-Initiated Oxidation of Mercury in the Global Atmosphere Without Violating Physical Laws

We present a way for modelers to include the OH + Hg reaction while accounting quantitatively for the dissociation of HOHg•. We use high levels of quantum chemistry to establish the HO-Hg bond energy as 11.0 kcal/mole, and calculate the equilibrium constant for OH + Hg = HOHg•. Using the measured rate constant for association of OH with Hg, we determine the rate constant for HOHg• dissociation. Theory is also used to demonstrate that HOHg• forms stable compounds, HOHgY, with atmospheric radicals (Y = NO2, HOO•, CH3OO•, and BrO). We then present rate constants for use in in modeling OH-initiated oxidation of Hg(0). We use this mechanism to model the global oxidation of Hg(0) in the period 2013-2015 using the GEOS-Chem 3D model of atmospheric chemistry. Because of the rapid dissociation of HOHg•, OH accounts for <1% of the global oxidation of Hg(0) to Hg(II), while Br atoms account for 97%.

Modeling the OH-Initiated Oxidation of Mercury in the Global Atmosphere Without Violating Physical Laws

We present a way for modelers to include the OH + Hg reaction while accounting quantitatively for the dissociation of HOHg•. We use high levels of quantum chemistry to establish the HO-Hg bond energy as 11.0 kcal/mole, and calculate the equilibrium constant for OH + Hg = HOHg•. Using the measured rate constant for association of OH with Hg, we determine the rate constant for HOHg• dissociation. Theory is also used to demonstrate that HOHg• forms stable compounds, HOHgY, with atmospheric radicals (Y = NO2, HOO•, CH3OO•, and BrO). We then present rate constants for use in in modeling OH-initiated oxidation of Hg(0). We use this mechanism to model the global oxidation of Hg(0) in the period 2013-2015 using the GEOS-Chem 3D model of atmospheric chemistry. Because of the rapid dissociation of HOHg•, OH accounts for <1% of the global oxidation of Hg(0) to Hg(II), while Br atoms account for 97%.

Modeling the OH-Initiated Oxidation of Mercury in the Global Atmosphere Without Violating Physical Laws

We present a way for modelers to include the OH + Hg reaction while accounting quantitatively for the dissociation of HOHg•. We use high levels of quantum chemistry to establish the HO-Hg bond energy as 11.0 kcal/mole, and calculate the equilibrium constant for OH + Hg = HOHg•. Using the measured rate constant for association of OH with Hg, we determine the rate constant for HOHg• dissociation. Theory is also used to demonstrate that HOHg• forms stable compounds, HOHgY, with atmospheric radicals (Y = NO2, HOO•, CH3OO•, and BrO). We then present rate constants for use in in modeling OH-initiated oxidation of Hg(0). We use this mechanism to model the global oxidation of Hg(0) in the period 2013-2015 using the GEOS-Chem 3D model of atmospheric chemistry. Because of the rapid dissociation of HOHg•, OH accounts for <1% of the global oxidation of Hg(0) to Hg(II), while Br atoms account for 97%.

The excitation of NH2 in the interstellar medium

ABSTRACT Accurate estimation of the abundance of the NH2 radical in the interstellar medium requires accurate radiative and collisional rate coefficients. The calculation of hyperfine-resolved rate coefficients for the collisional (de-)excitation of NH2 by both ortho- and para-H2 is presented in this work. Hyperfine-resolved rate coefficients are calculated from pure rotational close-coupling rate coefficients using the Mj randomizing approximation. Rate coefficients for temperatures ranging from 5 to 150 K were computed for all hyperfine transitions among the first 15 rotational energy levels of both ortho- and para-NH2 in collisions with ortho- and para-H2. The new data were then employed in radiative transfer calculations to simulate the excitation of NH2 in typical star-forming regions such as W31C, where NH2 is seen in emission. We compared the excitation and brightness temperatures for different NH2 transitions obtained using the new and the previously available collisional data. It is found that the new rate coefficients increase the simulated line intensities by a factor ∼10–30. As a consequence, NH2 abundance derived from the observations will be significantly reduced by the use of the present rate coefficients.

A study on knowledge, attitude and practice about organ donation among college students in Telangana state

Background: The change of disease pattern from communicable to non communicable or chronic diseases leading to end stage organ damage has led to the increase in the requirement of organ transplantation. Though the quality of organ transplantation has improved, the organ transplantation rate in India is 0.26 per million. Such a low rate is due to the lack of knowledge and misconception about organ donation.Methods: A pre-tested, semi-structured questionnaire was prepared, participants were chosen at random from the study population, they were interviewed with the questionnaire and their responses were computed and analysed.Results: In this study population, all of them knew about organ donation. The study shows that 62.7% of the students have adequate knowledge about organ donation. 67% of them would like to donate organs in future and 85% were willing to motivate their family to be an organ donor.Conclusions: The present rate of organ transplantation would be improved only when the society is educated with the knowledge, uncover the myths and misconceptions. It is also important that the organizations as to where and how to approach for the donation is known to all. Media being a powerful weapon of the generation can be a great tool to reach the society.

Prospects for Sustainable Power and Moderate Climate

A summary of the ongoing conversion from fossil fuel energy economy to sustainable energy is offered. A large fraction of the energy-related work force in the US has shifted to renewables, typified by the high demand for wind turbine technicians. A plan for full conversion to sustainable energy has been offered by Jacobson and collaborators, depending upon increased energy storage using underground thermal storage (UTES), thermal salt application in solar thermal installations, and pumped hydro. Hothouse earth events, extinguishing nearly all life, in climatic history are mentioned. The chance for triggering a future global hyperthermal event appears to be small from the excess carbon emissions of the past two centuries, with the present rate of emission.

New stellar encounters discovered in the second Gaia data release

Passing stars may play an important role in the evolution of our solar system. We search for close stellar encounters to the Sun among all 7.2 million stars in Gaia DR2 that have six-dimensional phase space data. We characterize encounters by integrating their orbits through a Galactic potential and propagating the correlated uncertainties via a Monte Carlo resampling. After filtering to remove spurious data, we find 694 stars that have median (over uncertainties) closest encounter distances within 5 pc, all occurring within 15 Myr from now. 26 of these have at least a 50% chance of coming closer than 1 pc (and 7 within 0.5 pc), all but one of which are newly discovered here. We confirm some and refute several other previously-identified encounters, confirming suspicions about their data. The closest encounter in the sample is Gl 710, which has a 95% probability of coming closer than 0.08 pc (17 000 AU). Taking mass estimates obtained from Gaia astrometry and multiband photometry for essentially all encounters, we find that Gl 710 also has the largest impulse on the Oort cloud. Using a Galaxy model, we compute the completeness of the Gaia DR2 encountering sample as a function of perihelion time and distance. Only 15% of encounters within 5 pc occurring within ±5 Myr of now have been identified, mostly due to the lack of radial velocities for faint and/or cool stars. Accounting for the incompleteness, we infer the present rate of encounters within 1 pc to be 19.7 ± 2.2 per Myr, a quantity expected to scale quadratically with the encounter distance out to at least several pc. Spuriously large parallaxes in our sample from imperfect filtering would tend to inflate both the number of encounters found and this inferred rate. The magnitude of this effect is hard to quantify.