Study of compensation process of ion beams

For investigation of space charge compensation process due to residual gas ionization and the experimentally study of the rise of compensation, a Low Energy Beam Transport (LEBT) system consisting of an ion source, two solenoids, a decompensation electrode to generate a pulsed decompensated ion beam and a diagnostic section was set up. The potentials at the beam axis and the beam edge were ascertained from time resolved measurements by a residual gas ion energy analyzer. A numerical simulation of self-consistent equilibrium states of the beam plasma has been developed to determine plasma parameters which are difficult to measure directly. The temporal development of the kinetic and potential energy of the compensation electrons has been analyzed by using the numerically gained results of the simulation. To investigate the compensation process the distribution and the losses of the compensation electrons were studied as a function of time. The acquired data show that the theoretical estimated rise time of space charge compensation neglecting electron losses is shorter than the build up time determined experimentally. To describe the process of space charge compensation an interpretation of the achieved results is given

Investigation of the rise of compensation of high perveance ion beams using a time-resolving ion energy spectrometer

The knowledge of the build up time of space charge compensation (SCC) and the investigation of the compensation process is of main interest for low energy beam transport of pulsed high perveance ion beams under space charge compensated conditions. To investigate experimentally the rise of compensation an LEBT system consisting of a pulsed ion source, two solenoids and a drift tube as diagnostic section has been set up. The beam potential has been measured time resolved by a residual gas ion energy analyser (RGA). A numerical simulation for the calculation of self-consistent equilibrium states of the beam plasma has been developed to determine plasma parameters which are difficult measure directly. The results of the simulation has been compared with the measured data to investigate the behavior of the compensation electrons as a function of time. The acquired data shows that the theoretical rise time of space charge compensation is by a factor of two shorter than the build up time determined experimentally. In view of description the process of SCC an interpretation of the gained results is given

Scenario generation and scenario quality using the cone of plausibility

The intelligence analysis domain is a critical area for futures work. Indeed, intelligence analysts’ judgments of security threats are based on considerations of how futures may unfold, and as such play a vital role in informing policy- and decision-making. In this domain, futures are typically considered using qualitative scenario generation techniques such as the cone of plausibility (CoP). We empirically examined the quality of scenarios generated using this technique on five criteria: completeness, context (otherwise known as ‘relevance/pertinence’), plausibility, coherence, and order effects (i.e., ‘transparency’). Participants were trained to use the CoP and then asked to generate scenarios that might follow within six months of the Turkish government banning Syrian refugees from entering the country. On average, participants generated three scenarios, and these could be characterized as baseline, best case, and worst case. All scenarios were significantly more likely to be of high quality on the ‘coherence’ criterion compared to the other criteria. Scenario quality was independent of scenario type. However, scenarios generated first were significantly more likely to be of high quality on the context and order effects criteria compared to those generated afterwards. We discuss the implications of these findings for the use of the CoP as well as other qualitative scenario generation techniques in futures studies

Using scenarios to forecast outcomes of a refugee crisis

The Syrian civil war has led to millions of Syrians fleeing the country, and has resulted in a humanitarian crisis. By considering how such socio-political events may unfold, scenarios can lead to informed forecasts that can be used for decision-making. We examined the relationship between scenarios and forecasts in the context of the Syrian refugee crisis. Forty Turkish students trained to use a brainstorming technique generated scenarios that might follow within six months of the Turkish government banning Syrian refugees from entering the country. Participants generated from 3-6 scenarios. Over half were rated as ‘high’ quality in terms of completeness, relevance/pertinence, plausibility, coherence, and transparency (order effects). Scenario quality was unaffected by scenario quantity. Even though no forecasts were requested, participants’ first scenarios contained from 0-17 forecasts. Mean forecast accuracy was 45% and this was unaffected by forecast quantity. Therefore, brainstorming can offer a simple and quick way of generating scenarios and forecasts that can potentially help decision-makers tackle humanitarian crises

Tree balance indices: a comprehensive survey

Tree balance plays an important role in phylogenetics and other research areas, which is why several indices to measure tree balance have been introduced over the years. Nevertheless, a formal definition of what a balance index actually is and what makes it a useful measure of balance (or, in other cases, imbalance), has so far not been introduced in the literature. While the established indices all summarize the (im)balance of a tree in a single number, they vary in their definitions and underlying principles. It is the aim of the present manuscript to introduce formal definitions of balance and imbalance indices that classify desirable properties of such indices and to analyze and categorize established indices accordingly. In this regard, we review 19 established (im)balance indices from the literature, summarize their general, statistical and combinatorial properties (where known), prove numerous additional results and indicate directions for future research by making explicit open questions and gaps in the literature. We also prove that a few tree shape statistics that have been used to measure tree balance in the literature do not fulfill our definition of an (im)balance index, which might indicate that their properties are not as useful for practical purposes. Moreover, we show that five additional tree shape statistics from other contexts actually are tree (im)balance indices according to our definition. The manuscript is accompanied by the website containing fact sheets of the discussed indices. Moreover, we introduce the software package \verb|treebalance| implemented in R that can be used to calculate all indices discussed.1 Introduction 2 Preliminaries 3 Summary of tree balance indices 4 Obtaining new balance indices from established indices 5 Normalizing balance indices 6 Related concepts 7 Software 8 Discussion and outlook 9 Fact sheet

Take my hand: a guide to seduction in late eighteenth-century opera

Late eighteenth-century French and Italian culture reflected an obsession with love and relationships through literature, music, and other art forms. Seduction scenes are one type of commentary on relationships that dot the landscape of opera of the time. The operatic seduction scene involves not only the two characters on stage but also a third agent – the music. After situating operatic seduction in the broader context of late eighteenth-century French and Italian culture, this thesis outlines the specific musical vocabulary of seduction that was put to use by composers, enacted on stage, and understood by audiences. This vocabulary is then applied to several case studies in the music of Mozart, who is now viewed as the dominant opera composer of the time, and his contemporaries. Through creative application and manipulation of the musical language of seduction, composers create ambiguous situations and invest the music with dramatic agency, allowing it to support, subvert, or otherwise comment on the seduction occurring on stage

Sprinting Velocity Increases Through Postactivation Potentiation with a Hex-Bar Farmers Walk

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Low-ILUC-risk rapeseed biodiesel:potential and indirect GHG emission effects in Eastern Romania

Indirect land-use change (ILUC) can have a severe impact on the greenhouse gas (GHG) balance of biofuels. Mitigating ILUC risk is important to avoid additional GHG emissions compared to fossil fuels. This is possible by making surplus land available through land demand reduction and using this for low-ILUC-risk biodiesel production. For a case study in Eastern Romania, we calculated the rapeseed biodiesel potential and the GHG emissions of four measures to make surplus land available in 2020. Four scenarios varying in assumptions on productivity and sustainability in the agricultural sector show the variation in the potential of these measures. We find that using surplus land to produce low-ILUC-risk rapeseed biodiesel has a potential of 3-64 PJ, 1-28% of the projected Romanian transport diesel consumption. The main contribution to this potential comes from yield improvements in crop and livestock production. Average GHG emissions of the ILUC mitigation measures are -11 to 22 g CO2-eq MJ−1 (maximum total lifecycle emissions are 34 g CO2-eq MJ−1; 60% reduction from fossil fuel reference). This means ILUC mitigation is possible without necessarily missing the GHG emission reduction target, provided that the entire agricultural sector is sustainably intensified, going beyond a focus on biofuel production alone

Projecting socio-economic impacts of bioenergy:Current status and limitations of ex-ante quantification methods

The socio-economic effects of bio-energy are not unequivocally positive, although it is one of the main arguments for supporting its expansion. An ex-ante quantification of the impacts is necessary for transparently presenting the benefits and burdens of bioenergy before they occur, and for minimising unwanted outcomes. In this article, the status, limitations, and possibilities for improvements in ex-ante quantitative research methods for investigating socio-economic impacts of bioenergy are mapped. For this, a literature review to identify relevant indicators, analyse the latest quantitative ex-ante research methods, and to assess their ability and suitability to measure these indicators was performed. The spatial aggregation of existing analyses was specifically considered because quantitative information on different spatial scales shows the geographic distribution of the effects. From the 236 indicators of socio-economic impacts spread over twelve impact categories that were found in this review, it becomes evident that there are clear differences in the ex-ante quantification of these indicators. The review shows that some impact categories receive more attention in ex-ante quantification studies, such as project-level economic feasibility and national-level macroeconomic impacts, while other relevant indicators have not been ex-ante quantified, such as community impacts and public acceptance. Moreover, a key blind spot regarding food security impacts was identified in the aggregation level at which food security impacts are quantified, which does not match the level at which the impacts occur. The review also shows that much more can be done in terms of ex-ante quantification of these impacts. Specifically, spatial disaggregation of models and model collaboration can extend the scope of socio-economic analyses. This is demonstrated for food security impacts, which shows the potential for future household-level analysis of food security impacts on all four pillars of food security

Structural basis for c-di-AMP–dependent regulation of the bacterial stringent response by receptor protein DarB

The bacterial second messenger c-di-AMP controls essential cellular processes, including potassium and osmolyte homeostasis. This makes synthesizing enzymes and components involved in c-di-AMP signal transduction intriguing as potential targets for drug development. The c-di-AMP receptor protein DarB of Bacillus subtilis binds the Rel protein and triggers the Rel-dependent stringent response to stress conditions; however, the structural basis for this trigger is unclear. Here, we report crystal structures of DarB in the ligand-free state and of DarB complexed with c-di-AMP, 3′3′-cGAMP, and AMP. We show that DarB forms a homodimer with a parallel, head-to-head assembly of the monomers. We also confirm the DarB dimer binds two cyclic dinucleotide molecules or two AMP molecules; only one adenine of bound c-di-AMP is specifically recognized by DarB, while the second protrudes out of the donut-shaped protein. This enables DarB to bind also 3′3′-cGAMP, as only the adenine fits in the active site. In absence of c-di-AMP, DarB binds to Rel and stimulates (p)ppGpp synthesis, whereas the presence of c-di-AMP abolishes this interaction. Furthermore, the DarB crystal structures reveal no conformational changes upon c-di-AMP binding, leading us to conclude the regulatory function of DarB on Rel must be controlled directly by the bound c-di-AMP. We thus derived a structural model of the DarB–Rel complex via in silico docking, which was validated with mass spectrometric analysis of the chemically crosslinked DarB–Rel complex and mutagenesis studies. We suggest, based on the predicted complex structure, a mechanism of stringent response regulation by c-di-AMP