Short-term impacts of enhanced Greenland freshwater fluxes in an eddy-permitting ocean model

In a sensitivity experiment, an eddy-permitting ocean general circulation model is forced with realistic freshwater fluxes from the Greenland Ice Sheet, averaged for the period 1991–2000. The fluxes are obtained with a mass balance model for the ice sheet, forced with the ERA-40 reanalysis dataset. The freshwater flux is distributed around Greenland as an additional term in prescribed runoff, representing seasonal melting of the ice sheet and a fixed year-round iceberg calving flux, for 8.5 model years. By adding Greenland freshwater fluxes with realistic geographical distribution and seasonality, the experiment is designed to investigate the oceanic response to a sudden and spatially/temporally uniform amplification of ice sheet melting and discharge, rather than localized or gradual changes in freshwater flux. The impacts on regional hydrography and circulation are investigated by comparing the sensitivity experiment to a control experiment, without additional fluxes. By the end of the sensitivity experiment, the majority of additional fresh water has accumulated in Baffin Bay, and only a small fraction has reached the interior of the Labrador Sea, where winter mixed layer depth is sensitive to small changes in salinity. As a consequence, the impact on large-scale circulation is very slight. An indirect impact of strong freshening off the west coast of Greenland is a small anti-cyclonic component to the circulation around Greenland, which opposes the wind-driven cyclonic circulation and reduces net southward flow through the Canadian Archipelago by ~10%. Implications for the post-2000 acceleration of Greenland mass loss are discussed

Entangling quantum measurement and its properties

We study the mathematical structure of superoperators describing quantum measurements, including the \emph{entangling measurement}--the generalization of the standard quantum measurement that results in entanglement between the measurable system and apparatus. It is shown that the coherent information can be effectively used for the analysis of such entangling measurements whose possible applications are discussed as well.Comment: 8 pages, 1 figure; accepted for publication in Phys. Rev.

Shapes of the 192,190^{192,190}Pb ground states from beta decay studies using the total absorption technique

The beta decay of $^{192,190}$Pb has been studied using the total absorption technique at the ISOLDE(CERN) facility. The beta-decay strength deduced from the measurements, combined with QRPA theoretical calculations, allow us to infer that the ground states of the $^{192,190}$Pb isotopes are spherical. These results represent the first application of the shape determination method using the total absorption technique for heavy nuclei and in a region where there is considerable interest in nuclear shapes and shape effects

Non-Invasive Mouse Models of Post-Traumatic Osteoarthritis

SummaryAnimal models of osteoarthritis (OA) are essential tools for investigating the development of the disease on a more rapid timeline than human OA. Mice are particularly useful due to the plethora of genetically modified or inbred mouse strains available. The majority of available mouse models of OA use a joint injury or other acute insult to initiate joint degeneration, representing post-traumatic osteoarthritis (PTOA). However, no consensus exists on which injury methods are most translatable to human OA. Currently, surgical injury methods are most commonly used for studies of OA in mice; however, these methods may have confounding effects due to the surgical/invasive injury procedure itself, rather than the targeted joint injury. Non-invasive injury methods avoid this complication by mechanically inducing a joint injury externally, without breaking the skin or disrupting the joint. In this regard, non-invasive injury models may be crucial for investigating early adaptive processes initiated at the time of injury, and may be more representative of human OA in which injury is induced mechanically. A small number of non-invasive mouse models of PTOA have been described within the last few years, including intra-articular fracture of tibial subchondral bone, cyclic tibial compression loading of articular cartilage, and anterior cruciate ligament (ACL) rupture via tibial compression overload. This review describes the methods used to induce joint injury in each of these non-invasive models, and presents the findings of studies utilizing these models. Altogether, these non-invasive mouse models represent a unique and important spectrum of animal models for studying different aspects of PTOA

Исследовательская деятельность эколого-биологической направленности в НОУ "Эврика" - эффективное средство профессиональной ориентации учащихся

В статье научно-исследовательская деятельность эколого-биологической направленности старшеклассников НОУ "Эврика" г. Нижнего Новгорода рассматривается как одна из значимых инновационных форм профессионального самоопределения. Материалом исследования послужил анализ программ конференции городского научного общества учащихся "Эврика" и судьбы выпускников данного общества. Отмечена тенденция роста популярности эколого-биологических исследований среди старшеклассников г. Нижнего Новгорода и успешное вхождение в профессию выпускников научного общества учащихся.In the article, the research activity of the ecology and biology of senior pupils of the scientific society of the pupils "Eureka" in Nizhny Novgorod is considered as one of the significant innovative forms of professional self-determination. The material of the study was the analysis of the programs of the conference of the city scientific society of the students "Eureka" and the fate of the graduates of this society. The tendency of growth of popularity of ecological and biological researches among senior pupils of Nizhny Novgorod and successful entry into the profession of graduates of the scientific society of students is noted

Energetic particle influence on the Earth's atmosphere

This manuscript gives an up-to-date and comprehensive overview of the effects of energetic particle precipitation (EPP) onto the whole atmosphere, from the lower thermosphere/mesosphere through the stratosphere and troposphere, to the surface. The paper summarizes the different sources and energies of particles, principally galactic cosmic rays (GCRs), solar energetic particles (SEPs) and energetic electron precipitation (EEP). All the proposed mechanisms by which EPP can affect the atmosphere are discussed, including chemical changes in the upper atmosphere and lower thermosphere, chemistry-dynamics feedbacks, the global electric circuit and cloud formation. The role of energetic particles in Earth’s atmosphere is a multi-disciplinary problem that requires expertise from a range of scientific backgrounds. To assist with this synergy, summary tables are provided, which are intended to evaluate the level of current knowledge of the effects of energetic particles on processes in the entire atmosphere

The global atmospheric electrical circuit and climate

Evidence is emerging for physical links among clouds, global temperatures, the global atmospheric electrical circuit and cosmic ray ionisation. The global circuit extends throughout the atmosphere from the planetary surface to the lower layers of the ionosphere. Cosmic rays are the principal source of atmospheric ions away from the continental boundary layer: the ions formed permit a vertical conduction current to flow in the fair weather part of the global circuit. Through the (inverse) solar modulation of cosmic rays, the resulting columnar ionisation changes may allow the global circuit to convey a solar influence to meteorological phenomena of the lower atmosphere. Electrical effects on non-thunderstorm clouds have been proposed to occur via the ion-assisted formation of ultra-fine aerosol, which can grow to sizes able to act as cloud condensation nuclei, or through the increased ice nucleation capability of charged aerosols. Even small atmospheric electrical modulations on the aerosol size distribution can affect cloud properties and modify the radiative balance of the atmosphere, through changes communicated globally by the atmospheric electrical circuit. Despite a long history of work in related areas of geophysics, the direct and inverse relationships between the global circuit and global climate remain largely quantitatively unexplored. From reviewing atmospheric electrical measurements made over two centuries and possible paleoclimate proxies, global atmospheric electrical circuit variability should be expected on many timescale

Interactions of amphipathic α-helical MEG proteins from Schistosoma mansoni with membranes

Micro Exon Gene (MEG) proteins are thought to play major roles in the infection and survival of parasitic Schistosoma mansoni worms in host organisms. Here, the physical chemical properties of two small MEG proteins found in the genome of S. mansoni, named MEG-24 and MEG-27, were examined by a combination of biophysical techniques such as differential scanning calorimetry, tensiometry, circular dichroism, fluorescence, and electron spin resonance spectroscopies. The proteins are surface active and structurally arranged as cationic amphipathic α-helices that can associate with lipid membranes and cause their disruption. Upon adsorption to lipid membranes, MEG-27 strongly affects the fluidity of erythrocyte ghost membranes, whereas MEG-24 forms pores in erythrocytes without modifying the ghost membrane fluidity. Whole–mount in situ hybridization experiments indicates that MEG-27 and MEG-24 transcripts are located in the parasite esophagus and subtegumental cells, respectively, suggesting a relevant role of these proteins in the host-parasite interface. Taken together, these characteristics lead us to propose that these MEG proteins may interact with host cell membranes and potentially modulate the immune process using a similar mechanism as that described for α-helical membrane–active peptides

Study of the deformation-driving vd5/2 orbital in 6728Ni39 using one-neutron transfer reactions

Abstract The ν g 9 / 2 , d 5 / 2 , s 1 / 2 orbitals are assumed to be responsible for the swift onset of collectivity observed in the region below 68Ni. Especially the single-particle energies and strengths of these orbitals are of importance. We studied such properties in the nearby 67Ni nucleus, by performing a ( d , p ) -experiment in inverse kinematics employing a post-accelerated radioactive ion beam (RIB) at the REX-ISOLDE facility. The experiment was performed at an energy of 2.95 MeV/u using a combination of the T-REX particle detectors, the Miniball γ-detection array and a newly-developed delayed-correlation technique as to investigate μs-isomers. Angular distributions of the ground state and multiple excited states in 67Ni were obtained and compared with DWBA cross-section calculations, leading to the identification of positive-parity states with substantial ν g 9 / 2 (1007 keV) and ν d 5 / 2 (2207 keV and 3277 keV) single-particle strengths up to an excitation energy of 5.8 MeV. 50% of the ν d 5 / 2 single-particle strength relative to the ν g 9 / 2 -orbital is concentrated in and shared between the first two observed 5 / 2 + levels. A comparison with extended Shell Model calculations and equivalent (3He, d) studies in the region around 9040Zr50 highlights similarities for the strength of the negative-parity pf and positive-parity g 9 / 2 state, but differences are observed for the d 5 / 2 single-particle strength