Clouds, photolysis and regional tropospheric ozone budgets.

We use a three-dimensional chemical transport model to examine the shortwave radiative effects of clouds on the tropospheric ozone budget. In addition to looking at changes in global concentrations as previous studies have done, we examine changes in ozone chemical production and loss caused by clouds and how these vary in different parts of the troposphere. On a global scale, we find that clouds have a modest effect on ozone chemistry, but on a regional scale their role is much more significant, with the size of the response dependent on the region. The largest averaged changes in chemical budgets (±10–14%) are found in the marine troposphere, where cloud optical depths are high. We demonstrate that cloud effects are small on average in the middle troposphere because this is a transition region between reduction and enhancement in photolysis rates. We show that increases in boundary layer ozone due to clouds are driven by large-scale changes in downward ozone transport from higher in the troposphere rather than by decreases in in-situ ozone chemical loss rates. Increases in upper tropospheric ozone are caused by higher production rates due to backscattering of radiation and consequent increases in photolysis rates, mainly J(NO2). The global radiative effect of clouds on isoprene, through decreases of OH in the lower troposphere, is stronger than on ozone. Tropospheric isoprene lifetime increases by 7% when taking clouds into account. We compare the importance of clouds in contributing to uncertainties in the global ozone budget with the role of other radiatively-important factors. The budget is most sensitive to the overhead ozone column, while surface albedo and clouds have smaller effects. However, uncertainty in representing the spatial distribution of clouds may lead to a large sensitivity of the ozone budget components on regional scales

Technical Note: Adjoint formulation of the TOMCAT atmospheric transport scheme in the Eulerian backtracking framework (RETRO-TOM)

A new methodology for the formulation of an adjoint to the transport component of the chemistry transport model TOMCAT is described and implemented in a new model, RETRO-TOM. The Eulerian backtracking method is used, allowing the forward advection scheme (Prather's second-order moments) to be efficiently exploited in the backward adjoint calculations. Prather's scheme is shown to be time symmetric, suggesting the possibility of high accuracy. To attain this accuracy, however, it is necessary to make a careful treatment of the "density inconsistency" problem inherent to offline transport models. The results are verified using a series of test experiments. These demonstrate the high accuracy of RETRO-TOM when compared with direct forward sensitivity calculations, at least for problems in which flux limiters in the advection scheme are not required. RETRO-TOM therefore combines the flexibility and stability of a "finite difference of adjoint" formulation with the accuracy of an "adjoint of finite difference" formulation

Improving Agricultural Irrigation on the Balkhab River, Afghanistan

In Afghanistan, where 80% of the population is rural, irrigated agriculture is important for satisfying subsistence needs. While most of the irrigated agriculture is fed by diversion canal systems which tap surface flows, legal and physical water infrastructure in the region is generally poor. A math programming model is used to optimize irrigation strategies under different water-availability and policy scenarios. It is found that the construction of a reservoir could increase net revenues to a representative farming community by up to 30%. However, even greater benefits may result from increasing distribution efficiencies, depending on the initial level of conveyance losses. Further, property rights schemes may be implemented to distribute wealth more evenly through various zones at minimal cost to the agricultural community as a whole. These results may prove useful to policymakers or water authorities in reestablishing water rights.linear programming, irrigation, Afghanistan, Agricultural and Food Policy, Community/Rural/Urban Development, International Development,

Interannual variability of tropospheric composition:the influence of changes in emissions, meteorology and clouds

We have run a chemistry transport model (CTM) to systematically examine the drivers of interannual variability of tropospheric composition during 1996-2000. This period was characterised by anomalous meteorological conditions associated with the strong El Nino of 1997-1998 and intense wildfires, which produced a large amount of pollution. On a global scale, changing meteorology (winds, temperatures, humidity and clouds) is found to be the most important factor driving interannual variability of NO2 and ozone on the timescales considered. Changes in stratosphere-troposphere exchange, which are largely driven by meteorological variability, are found to play a particularly important role in driving ozone changes. The strong influence of emissions on NO2 and ozone interannual variability is largely confined to areas where intense biomass burning events occur. For CO, interannual variability is almost solely driven by emission changes, while for OH meteorology dominates, with the radiative influence of clouds being a very strong contributor. Through a simple attribution analysis for 1996-2000 we conclude that changing cloudiness drives 25% of the interannual variability of OH over Europe by affecting shortwave radiation. Over Indonesia this figure is as high as 71%. Changes in cloudiness contribute a small but non-negligible amount (up to 6%) to the interannual variability of ozone over Europe and Indonesia. This suggests that future assessments of trends in tropospheric oxidizing capacity should account for interannual variability in cloudiness, a factor neglected in many previous studies

Simple Cardiac Screening of NCAA and USAC Collegiate Athletes Using Smartphone Electrocardiogram

Please refer to the pdf version of the abstract located adjacent to the title

Magnetic relaxation studies on a single-molecule magnet by time-resolved inelastic neutron scattering

Time-resolved inelastic neutron scattering measurements on an array of single-crystals of the single-molecule magnet Mn12ac are presented. The data facilitate a spectroscopic investigation of the slow relaxation of the magnetization in this compound in the time domain.Comment: 3 pages, 4 figures, REVTEX4, to appear in Appl. Phys. Lett., for an animation see also http://www.dcb.unibe.ch/groups/guedel/members/ow2/trins.ht

Voltage control of nuclear spin in ferromagnetic Schottky diodes

We employ optical pump-probe spectroscopy to investigate the voltage dependence of spontaneous electron and nuclear spin polarizations in hybrid MnAs/n-GaAs and Fe/n-GaAs Schottky diodes. Through the hyperfine interaction, nuclear spin polarization that is imprinted by the ferromagnet acts on conduction electron spins as an effective magnetic field. We demonstrate tuning of this nuclear field from <0.05 to 2.4 kG by varying a small bias voltage across the MnAs device. In addition, a connection is observed between the diode turn-on and the onset of imprinted nuclear polarization, while traditional dynamic nuclear polarization exhibits relatively little voltage dependence.Comment: Submitted to Physical Review B Rapid Communications. 15 pages, 3 figure

Trait self-control and beliefs about the utility of emotions for initiatory and inhibitory self-control

How do people with high trait self-control achieve their success? This research aimed to provide evidence for beliefs about emotion utility as a potential mechanism. Specifically, because beliefs about the utility of emotions predict emotion regulation and successful performance, we investigate the hypothesis that trait self-control influences beliefs about the utility of emotions for self-control. Two preregistered studies examined whether beliefs about the utility of emotions in everyday self-control situations varied depending on the person (trait self-control) and the situation (initiatory or inhibitory self-control). Our key finding was that people considered positive emotions more useful for self-control than negative emotions. This effect was also moderated by situational and individual factors, such that positive emotions were considered especially useful by participants with high trait self-control and in situations requiring initiatory self-control (with the opposite effect for negative emotions). This research suggests a potential role for instrumental emotion regulation in self-control success

Exploring associations between parental and peer variables, personal variables and physical activity among adolescents: a mediation analysis

This study aimed to investigate how parental and peer variables are associated with moderate- to-vigorous intensity physical activity (MVPA) on week- and weekend days among Australian adolescents (13-15 y), and whether perceived internal barriers (e.g. lack of time), external barriers (e.g. lack of others to be physically active with) and self-efficacy mediated these associations

Agency, qualia and life: connecting mind and body biologically

Many believe that a suitably programmed computer could act for its own goals and experience feelings. I challenge this view and argue that agency, mental causation and qualia are all founded in the unique, homeostatic nature of living matter. The theory was formulated for coherence with the concept of an agent, neuroscientific data and laws of physics. By this method, I infer that a successful action is homeostatic for its agent and can be caused by a feeling - which does not motivate as a force, but as a control signal. From brain research and the locality principle of physics, I surmise that qualia are a fundamental, biological form of energy generated in specialized neurons. Subjectivity is explained as thermodynamically necessary on the supposition that, by converting action potentials to feelings, the neural cells avert damage from the electrochemical pulses. In exchange for this entropic benefit, phenomenal energy is spent as and where it is produced - which precludes the objective observation of qualia