Activity-dependent adenosine release may be linked to activation of Na+-K+ ATPase : an in vitro rat study

In the brain, extracellular adenosine increases as a result of neuronal activity. The mechanisms by which this occurs are only incompletely understood. Here we investigate the hypothesis that the Na+ influxes associated with neuronal signalling activate the Na+-K+ ATPase which, by consuming ATP, generates intracellular adenosine that is then released via transporters. By measuring adenosine release directly with microelectrode biosensors, we have demonstrated that AMPA-receptor evoked adenosine release in basal forebrain and cortex depends on extracellular Na+. We have simultaneously imaged intracellular Na+ and measured adenosine release. The accumulation of intracellular Na+ during AMPA receptor activation preceded adenosine release by some 90 s. By removing extracellular Ca2+, and thus preventing indiscriminate neuronal activation, we used ouabain to test the role of the Na+-K+ ATPase in the release of adenosine. Under conditions which caused a Na+ influx, brief applications of ouabain increased the accumulation of intracellular Na+ but conversely rapidly reduced extracellular adenosine levels. In addition, ouabain greatly reduced the amount of adenosine released during application of AMPA. Our data therefore suggest that activity of the Na+-K+ ATPase is directly linked to the efflux of adenosine and could provide a universal mechanism that couples adenosine release to neuronal activity. The Na+-K+ ATPase-dependent adenosine efflux is likely to provide adenosine-mediated activity-dependent negative feedback that will be important in many diverse functional contexts including the regulation of sleep

Early Archean tonalite gneiss in the upper peninsula of Michigan

Geochronological results on tonalite gneiss of northern Michigan that is 3.56 Ga or slightly older is presented. Tonalitic augen gneiss and structurally overlying biotite gneiss and schist are exposed in a dome near Watersmeet. They are part of an extensive gneiss terrane of southern Minnesota, Wisconsin and Michigan that includes rocks of early to late Archean ages and lies south of the Wawa volcanic subprovince. Two samples of the augen gneiss and one of the biotite gneiss show zircon grains of similar shape, zoning, color, and development of crystal faces. These zircons give Pb/U isotopic ratios that plot on a chord of 3,560 + or - 40 m.y. upper intersect and of 1,250 + or m.y. lower intersect. The 3,560 m.y. number is believed to be a minimum age because analysis of one of the least discordant zircon fractions by ion microprobe that gave a nearly concordant age of 3,650 m.y. The 1,250 m.y. lower intersect is without geological significance: it is interpreted to be a result of multiple lead loss at 2.7, 1.8, and 0.5 Ga by U/Pb in zircon. Archean rocks 10 to 25 km northwest of the Watersmeet dome give a 2.75 Ga age on zircons. Quartz monzonite here is dated at 2.65 Ga

Organochloride Pesticides Present in Animal Fur, Soil, and Streambed in an Agricultural Region of Southeastern Arkansas

Animals in agricultural settings may be subject to bioaccumulation of toxins. For the last several years, we collected hair samples from bats and rodents in an agricultural area near Bayou Bartholomew in Drew County, Arkansas. Samples were submitted to the Center of Environmental Sciences and Engineering at the University of Connecticut for wide-screen toxin analysis. Several of these samples contained measurable amounts of organochloride pesticides or their metabolites, including some that have been banned for decades, such as dichlorodiphenyltrichloroethane (DDT) and chlordane. In addition, we collected several samples of soil from within an agricultural field, from adjacent edge habitat, from alongside the bank of the Bayou, and from the bed of the Bayou itself. Although none of these samples tested positive for DDT or chlordane, all of the samples except one contained measurable amounts of metabolites from these pesticides. This study raises questions about environmental persistence of DDT/DDE and other organochlorides. There may be risk to wildlife populations, warranting further investigation into effects of long-term exposure to these toxins

Effect of Local Electron-Electron Correlation in Hydrogen-like Impurities in Ge

We have studied the electronic and local magnetic structure of the hydrogen interstitial impurity at the tetrahedral site in diamond-structure Ge, using an empirical tight binding + dynamical mean field theory approach because within the local density approximation (LDA) Ge has no gap. We first establish that within LDA the 1s spectral density bifurcates due to entanglement with the four neighboring sp3 antibonding orbitals, providing an unanticipated richness of behavior in determining under what conditions a local moment hyperdeep donor or Anderson impurity will result, or on the other hand a gap state might appear. Using a supercell approach, we show that the spectrum, the occupation, and the local moment of the impurity state displays a strong dependence on the strength of the local on-site Coulomb interaction U, the H-Ge hopping amplitude, the depth of the bare 1s energy level epsilon_H, and we address to some extent the impurity concentration dependence. In the isolated impurity, strong interaction regime a local moment emerges over most of the parameter ranges indicating magnetic activity, and spectral density structure very near (or in) the gap suggests possible electrical activity in this regime.Comment: 9 pages, 5 figure

Divorcing Speech Ability and Intelligence: Why the Two Can No Longer Be Strongly Linked Together

Human language is a complex cognitive ability that is still not fully understood by scientists. Except in rare occasions of extreme seclusion or disability, children are able to acquire language without explicitly being taught how. Though animals have the ability to communicate, their “languages” are not comparable to human language. Commonly, people believe that one’s language ability correlates directly to one’s intelligence. It is the purpose of this paper to explore that belief and test its veracity. My hypothesis is that this correlation does not exist or is at best weak. This will be done by looking at several language-related disorders and the effect they have on human speech

Femtosecond probing of bimolecular reactions: The collision complex

Progress has been made in probing the femtosecond dynamics of transition states of chemical reactions.(1) The "half-collision" case of unimolecular reactions has been experimentally investigated for a number of systems and much theoretical work has already been developed.(2) For bimolecular reactions, the case of full collision, the zero of time is a problem which makes the femtosecond temporal resolution of the dynamics a difficult task

Jainism and Nonviolence: From Mahavira to Modern Times

The research contained in this paper focuses on the religion of Jainism, its main principle of ahimsa, or nonviolence, and how that philosophy has evolved over the years, eventually inspiring today’s nonviolent movements. First, a look will be taken at the origin of Jainism, with a brief explanation of its most important principles and beliefs. Then, ahimsa is explained as it has been traditionally perceived by Jains. The recent evolution of the meaning of ahimsa and its impact on modern nonviolence movements is discussed, with a focus on the influence of second-generation Jains in the United States on the spread of the environmental movement in particular, as well as other prominent Jain figures who support this change in ideals. Finally, implications are made about the future of Jainism and how this renewed definition of ahimsa will affect the spread of the religion and its teachings of love and nonviolence around the world

Femtosecond real-time probing of reactions. VIII. The bimolecular reaction Br+I2

In this paper, we discuss the experimental technique for real-time measurement of the lifetimes of the collision complex of bimolecular reactions. An application to the atom–molecule Br+I_2 reaction at two collision energies is made. Building on our earlier Communication [J. Chem. Phys. 95, 7763 (1991)], we report on the observed transients and lifetimes for the collision complex, the nature of the transition state, and the dynamics near threshold. Classical trajectory calculations provide a framework for deriving the global nature of the reactive potential energy surface, and for discussing the real-time, scattering, and asymptotic (product-state distribution) aspects of the dynamics. These experimental and theoretical results are compared with the extensive array of kinetic, crossed beam, and theoretical studies found in the literature for halogen radical–halogen molecule exchange reactions

VALIDATION AND DESCRIPTIVE ANALYSIS OF THE SYSTEM FOR OBSERVING DANCE ACTIVITIES IN THE CLASSROOM ENVIRONMENT (SODANCE)

The first part of this study sought to validate the System for Observing Dance Activities in the Classroom Environment (SODANCE) based off the System for Observing Fitness Instructional Time (SOFIT). Female students age 11-17 years (N=42) participated in an activity protocol of SOFIT activities and common dance activities to validate appropriate coding categories. Each student wore a heart rate monitor and accelerometer while participating in the activities lying, sitting, standing, walking, running, single leg balances, leg swings, pirouettes, and leaps. Heart rate, maximum heart rate percentage, heart rate reserve percentage, vertical axis accelerometer counts, and vector magnitude accelerometer counts for each activity were classified as light, moderate, or vigorous. Ultimately heart rate reserve data was determined to be the best indicator of physical activity. The chi squared test was used to determine if there were significant differences in the proportion of subjects whose heart rate reserve data classified the activity as light vs. moderate vs. vigorous. Based upon the heart rate reserve data, each activity was assigned a SODANCE activity code of 1-5. The dance activities were coded as single leg balances 4, leg swings 4, pirouettes 5, and leaps 5. The second part of this study aimed to use the SODANCE instrument to collect data about the physical activity levels, time spent in MVPA, time spent in different lesson contexts, and frequency of teacher promotion of activity. Four different secondary (grades 6-12) dance technique classes (ballet or contemporary) at a public performing arts school were each observed four times using the SODANCE instrument. Students engaged in MVPA 40.62% of the time. Percentages of time spent in SODANCE lesson contents are as follows: management 9.53% (n=280), knowledge 22.29% (n=655), fitness 6.94% (n=204), technique 44.04% (n=1294), choreography 17.19% (n=505), and other 0.0% (n=0). Percentages of teacher interaction are as follows: promotes in-class activity 27.67% (n=813), promotes out-of-class activity 0.27% (n=8), and no promotion 72.06% (n=2117). These data suggests that dance technique classes offer equitable or more MVPA than physical education classes, but still short of the national recommendations