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The phenomenon of buying-shopping disorder (BSD) was described over 100 years ago. Definitions of BSD refer to extreme preoccupation with shopping and buying, to impulses to purchase that are experienced as irresistible, and to recurrent maladaptive buying excesses that lead to distress and impairments. Efforts to stop BSD episodes are unsuccessful, despite the awareness of repeated break-downs in self-regulation, experiences of post-purchase guilt and regret, comorbid psychiatric disorders, reduced quality of life, familial discord, work impairment, financial problems, and other negative consequences. A recent meta-analysis indicated an estimated point prevalence of BSD of 5%. In this narrative review, the authors offer a perspective to consider BSD as a mental health condition and to classify this disorder as a behavioral addiction, based on both research data and on long-standing clinical experience.
Periodicity seen in both the mass extinctions and large impact cratering on earth can be explained if one postulates that the sun has a companion star, orbiting in a moderately eccentric orbit with a major axis of 2.8 light-years. No other explanations that have been suggested are compatible with known facts of physics and astronomy. If the companion is a red dwarf star, the most common kind in the galaxy, then no previous astronomical observations would have found it. A search for red objects with large parallax is now underway at Berkeley, and has a good chance of identifying the star in the near future.
Elastic strain is an effective and thus widely used parameter to control and modify the electrical, optical, and magnetic properties of crystalline solid-state materials. It has a large impact on device performance and enables adjusting the materials functionality. Here, we promote a micromechanical strain enhancement technology to achieve ultra-high strain in semiconductors. The here presented suspended membranes enable the accurate control of the strain on a wafer-scale by standard top-down fabrication methods making it attractive for both device applications and also, thanks to the simplicity of the method, for fundamental research. This review aims at discussing the process of strain enhancement and its usage as an investigation platform for strain-related physical properties. Furthermore, we present design rules and a detailed analysis of fracture effects limiting the strain enhancement.
My path to the invention of accelerator mass spectrometry—now just called AMS—was quirky and extraordinary, and it is a saga worth telling, particularly for young people who may have an oversimplified image of how progress in science is actually made. It was an adventurous journey, and like many adventures, it was often uncomfortable, haphazard, and frequently characterized by a feeling of being lost. In retrospect, the only reason I set out on this journey was my belief that I didn't know much about finding my path in physics, and that the best I could do was to follow the lead of the great physicist Luis Alvarez. He had an incredible ability to create new and ingenious projects that led in new directions, and I wanted to understand how he did that. So I had decided that I would work with him on any new idea he came up with, even if it inconvenienced the rest of my life. And true to my expectations, while working with Luie (that's what he wanted everyone to call him), I often felt like Odysseus, tossed between distant shores by capricious gods.
The present report covers the period from 1 January 1979 to 31 December 1981. This period includes the first eight months (to 26 August) of the year 1979, which was part of the period in office of the previous Executive Committee; it does not include the first eight months of 1982, still the period of responsibility of the present Executive Committee (to 27 August 1982).
The address of the General Secretary at the XVIIIth General Assembly will include a report for the period 1 January – 16 August 1982.
This report includes a summarized financial report for the calendar years 1979, 1980 and 1981 and a budget proposal for the calendar year 1982, closing the 3-year budgetary period 1979-1982.
In stable populations with constant demographic rates, size distributions reflect size-dependent patterns of growth and mortality. However, population growth can also affect size distributions, which may not be aligned with current growth and mortality. Using 25 y of demographic data from the 50-ha Barro Colorado Island plot, we examined how interspecific variation in diameter distributions of over 150 tropical trees relates to growth–diameter and mortality–diameter curves and to population growth rates. Diameter distributions were more skewed in species with faster increases/slower decreases in absolute growth and mortality with diameter and higher population growth rates. The strongest predictor of the diameter distribution shape was the exponent governing the scaling of growth with diameter (partial R2 = 0.20–0.34), which differed among growth forms, indicating a role of life history variation. However, interspecific variation in diameter distributions was also significantly related to population growth rates (partial R2 = 0.03–0.23), reinforcing that many populations are not at equilibrium. Consequently, although fitted size distribution parameters were positively related to theoretical predictions based on current size-dependent growth and mortality, there was considerable deviation. These analyses show that temporally variable demographic rates, probably related to cyclic climate variation, are important influences on forest structure.
Increasing atmospheric carbon dioxide, changing climates, nitrogen deposition and other aspects of anthropogenic global change are hypothesised to be changing forest productivity and biomass stocks in tropical forests and elsewhere (Clark 2004; Lewis, Malhi & Phillips 2004; Lewis et al. 2009a; Luo, 2007; Myeni et al. 1997). These hypotheses continue to be much debated, with contrary views on the plausibility of particular mechanisms and on the status of current evidence for or against them (Clark 2007; Friedlingstein et al. 2006; Holtum & Winter 2010; Körner 2009; Wright 2005, 2010). The influence of atmospheric and climate change on forest biomass is of particular interest because of the potential for positive or negative feedbacks. Increases in forest biomass and associated carbon pools would slow the rise in atmospheric carbon dioxide, producing a negative feedback, whereas decreases in forest biomass would have the opposite effect. Uncertainty surrounding these feedbacks is considerable at the global scale, with important implications for global carbon budgets (Luo 2007).
In view of this, it is essential to know whether forests are experiencing changes in productivity and biomass in excess of those typical for their age. Successional forests, those regrowing after disturbances, increase in biomass over time, with the trajectory and duration of this increase varying with forest type (Bormann & Likens 1979; Odum 1969). In the absence of global change, such forests are expected to eventually reach a dynamic equilibrium in which biomass gains from growth and recruitment are balanced by biomass losses from tree death and branchfall, and these old-growth forests thus experience no directional changes in biomass (Odum 1969; Yang, Luo & Finzi 2011). Accordingly, detection of directional changes in biomass in old-growth forests is generally considered evidence of global change influences. When and where such changes are detected, the next critical question concerns prediction of future net carbon fluxes and ultimate carbon stocks of such altered forests.
Nitrification inhibitors are used in agriculture for the purpose of decreasing nitrogen (N) losses, by limiting the microbially mediated oxidation of ammonium (NH4+) to nitrate (NO3−). Successful inhibition of nitrification has been shown in numerous studies, but the extent to which inhibitors affect other N transformations in soil is largely unknown. In the present study, cattle slurry was applied to microcosms of three different grassland soils, with or without the nitrification inhibitor dicyandiamide (DCD). A solution containing NH4+ and NO3−, labelled with 15N either on the NH4+ or the NO3− part, was mixed with the slurry before application. Gross N transformation rates were estimated using a 15N tracing model. In all three soils, DCD significantly inhibited gross autotrophic nitrification, by 79–90%. Gross mineralization of recalcitrant organic N increased significantly with DCD addition in two soils, whereas gross heterotrophic nitrification from the same pool decreased with DCD addition in two soils. Fungal to bacterial ratios were not significantly affected by DCD addition. Total gross mineralization and immobilization increased significantly across the three soils when DCD was used, which suggests that DCD can cause non-target effects on soil N mineralization–immobilization turnover.
Many studies have shown the efficacy of the nitrification inhibitor dicyandiamide (DCD) in reducing nitrous oxide (N2O) emissions and nitrate (NO3−) leaching. However, there is no information on the effect of DCD on gross soil N transformations under field conditions, which is key information if it is to be used as a mitigation strategy to reduce N losses. The current field study was conducted to determine the effect of DCD on ten gross nitrogen (N) transformations in soil following cattle slurry (CS) application to grassland in Northern Ireland on three occasions (June 2010, October 2010 and March 2011).
Ammonium (NH4+) oxidation (ONH4) was the dominant process in total NO3− production (ONH4+ONrec (oxidation of recalcitrant organic N to NO3−)) following CS application, accounting for 0·894–0·949. Dicyandiamide inhibited total NO3− production from CS by 0·781, 0·696 and 0·807 in June 2010, October 2010 and March 2011, respectively. The lower inhibition level in October 2010 was thought to be due to the higher rainfall and soil moisture content in that month compared to the other application times. As DCD strongly inhibited NH4+ oxidation following CS application, it also decreased the rate of total NO3− consumption, since less NO3− was formed. The rates of mineralization from recalcitrant organic-N (MNrec) were higher than from labile organic-N (MNlab) on all occasions. The DCD significantly increased total mineralization (MNrec+MNlab) following CS application in June 2010 and March 2011, but had no significant effect in October 2010. In contrast, the rate of immobilization of labile organic-N (INH4_Nlab) was higher than from recalcitrant organic-N (INH4_Nrec) on all occasions, accounting for 0·878–0·976 of total NH4+ immobilization from CS. The DCD significantly increased total immobilization (INH4_Nrec+INH4_Nlab) when CS was applied in June 2010, but had no significant effect at other times of the year.
Dicyandiamide was shown to be a highly effective inhibitor of ammonium oxidation at this grassland site. Although there was evidence that it increased both NH4+ mineralization and immobilization following CS application, its effect on these processes was inconsistent. Further work is required to understand the reason for these inconsistent effects: future improvements in 15N tracer models may help.
The nitrogen (N) cycle is one of the best studied elemental cycles. However, the N flows and transformations, in particular in aggregated soils, at small scales and in plant–soil systems are not yet fully understood. Analytical and molecular techniques are now available to address N dynamics at small scales. The methodological advances should go hand in hand with the development of suitable mathematical models addressing the small scale and the full complexity of the many interacting effects. The importance of denitrification within the N cycle is highlighted and used as an example of the progress achieved in recent times. Research gaps and possible research pathways are outlined.
We provide a framework for studying randomly coloured point sets in a locally compact second-countable space on which a metrizable unimodular group acts continuously and properly. We first construct and describe an appropriate dynamical system for uniformly discrete uncoloured point sets. For point sets of finite local complexity, we characterize ergodicity geometrically in terms of pattern frequencies. The general framework allows us to incorporate a random colouring of the point sets. We derive an ergodic theorem for randomly coloured point sets with finite-range dependencies. Special attention is paid to the exclusion of exceptional instances for uniquely ergodic systems. The setup allows for a straightforward application to randomly coloured graphs
A phase field model is developed to investigate the formation of a solid electrolyte interface layer on the anode surface in lithium-ion batteries. Numerical results show that the growth of solid electrolyte interface exhibits power-law scaling with respect to time, and the growth rate depends on various factors such as temperature, diffusivity of electrons, and rates of electrochemical reactions.
The structural and magnetic properties of nano-sized particles of transition
metals (Co and Ni) implanted into amorphous SiO2 are
investigated. The SiO2 substrates used were as grown on a silicon
(100) wafer under wet O2 atmosphere. The metals were implanted as
singly charged atoms energized to 30 or 160 keV. Transmission Electron
microscopy (TEM) observations and X-ray absorption spectroscopy (XAS) show
that M+ implantation results in the formation of metallic
nanoparticles at the vicinity of the surface whereas oxide particles (< 1
nm) are formed in a deeper region. After thermal treatment under hydrogen,
TEM evidences the disappearance of the oxide region and an increase in the
size of the metallic particle. XAS shows that cobalt and nickel are entirely
in the metallic form and saturation magnetization becomes close to the
Gas phase chemistry is believed to play an important role in hot-wire CVD of amorphous silicon, serving to convert the highly-reactive atomic Si produced at the wire into a less-reactive species by reaction with ambient SiH4. In this paper, we use quantum chemistry computations (B3LYP/cc-pvTZ) to examine the energetics and rates of possible gas-phase reactions between Si and SiH4. The results indicate that formation of disilyne (Si2H2) is energetically favorable. Unlike other products of this reaction, Si2H2 does not require collisional stabilization, and thus this species is the most likely candidate for a benevolent precursor that participates in the growth of high-quality Si films.
In 1982, Kurt Petersen published “Silicon as a Mechanical Material” in the Proceedings of the IEEE. This thorough review article heightened focus on the advantages of utilizing the mechanical as well as electrical properties of single-crystal silicon. Processes for shaping single-crystal silicon based upon selective etching were shown in the article to make silicon useful for a variety of miniature mechanical devices.
A promising new concept of a diamond amplified photocathode for generation of high-current, high-brightness, and low thermal emittance electron beams was recently proposed and is currently under active development. To better understand the different effects involved, we have been developing models, within the VORPAL computational framework, to simulate secondary electron generation and charge transport in diamond. The implemented models include inelastic scattering of electrons and holes for generation of electron-hole pairs, elastic, phonon, and charge impurity scattering. We will discuss these models and present results from 3D VORPAL simulations on charge gain and collection efficiency as a function of primary electron energy and applied electric field. The implemented modeling capabilities already allow us to investigate specific effects and compare simulation results with experimental data.